kvm/x86: move Hyper-V MSR's/hypercall code into hyperv.c file

[deliverable/linux.git] / arch / x86 / kvm / x86.c

/*
 * Kernel-based Virtual Machine driver for Linux
 *
 * derived from drivers/kvm/kvm_main.c
 *
 * Copyright (C) 2006 Qumranet, Inc.
 * Copyright (C) 2008 Qumranet, Inc.
 * Copyright IBM Corporation, 2008
 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
 *
 * Authors:
 *   Avi Kivity   <avi@qumranet.com>
 *   Yaniv Kamay  <yaniv@qumranet.com>
 *   Amit Shah    <amit.shah@qumranet.com>
 *   Ben-Ami Yassour <benami@il.ibm.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 */

#include <linux/kvm_host.h>
#include "irq.h"
#include "mmu.h"
#include "i8254.h"
#include "tss.h"
#include "kvm_cache_regs.h"
#include "x86.h"
#include "cpuid.h"
#include "assigned-dev.h"
#include "pmu.h"
#include "hyperv.h"

#include <linux/clocksource.h>
#include <linux/interrupt.h>
#include <linux/kvm.h>
#include <linux/fs.h>
#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/mman.h>
#include <linux/highmem.h>
#include <linux/iommu.h>
#include <linux/intel-iommu.h>
#include <linux/cpufreq.h>
#include <linux/user-return-notifier.h>
#include <linux/srcu.h>
#include <linux/slab.h>
#include <linux/perf_event.h>
#include <linux/uaccess.h>
#include <linux/hash.h>
#include <linux/pci.h>
#include <linux/timekeeper_internal.h>
#include <linux/pvclock_gtod.h>
#include <trace/events/kvm.h>

#define CREATE_TRACE_POINTS
#include "trace.h"

#include <asm/debugreg.h>
#include <asm/msr.h>
#include <asm/desc.h>
#include <asm/mce.h>
#include <linux/kernel_stat.h>
#include <asm/fpu/internal.h> /* Ugh! */
#include <asm/pvclock.h>
#include <asm/div64.h>

#define MAX_IO_MSRS 256
#define KVM_MAX_MCE_BANKS 32
#define KVM_MCE_CAP_SUPPORTED (MCG_CTL_P | MCG_SER_P)

#define emul_to_vcpu(ctxt) \
        container_of(ctxt, struct kvm_vcpu, arch.emulate_ctxt)

/* EFER defaults:
 * - enable syscall per default because its emulated by KVM
 * - enable LME and LMA per default on 64 bit KVM
 */
#ifdef CONFIG_X86_64
static
u64 __read_mostly efer_reserved_bits = ~((u64)(EFER_SCE | EFER_LME | EFER_LMA));
#else
static u64 __read_mostly efer_reserved_bits = ~((u64)EFER_SCE);
#endif

#define VM_STAT(x) offsetof(struct kvm, stat.x), KVM_STAT_VM
#define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU

static void update_cr8_intercept(struct kvm_vcpu *vcpu);
static void process_nmi(struct kvm_vcpu *vcpu);
static void __kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags);

struct kvm_x86_ops *kvm_x86_ops;
EXPORT_SYMBOL_GPL(kvm_x86_ops);

static bool ignore_msrs = 0;
module_param(ignore_msrs, bool, S_IRUGO | S_IWUSR);

unsigned int min_timer_period_us = 500;
module_param(min_timer_period_us, uint, S_IRUGO | S_IWUSR);

static bool __read_mostly kvmclock_periodic_sync = true;
module_param(kvmclock_periodic_sync, bool, S_IRUGO);

bool kvm_has_tsc_control;
EXPORT_SYMBOL_GPL(kvm_has_tsc_control);
u32  kvm_max_guest_tsc_khz;
EXPORT_SYMBOL_GPL(kvm_max_guest_tsc_khz);

/* tsc tolerance in parts per million - default to 1/2 of the NTP threshold */
static u32 tsc_tolerance_ppm = 250;
module_param(tsc_tolerance_ppm, uint, S_IRUGO | S_IWUSR);

/* lapic timer advance (tscdeadline mode only) in nanoseconds */
unsigned int lapic_timer_advance_ns = 0;
module_param(lapic_timer_advance_ns, uint, S_IRUGO | S_IWUSR);

static bool backwards_tsc_observed = false;

#define KVM_NR_SHARED_MSRS 16

struct kvm_shared_msrs_global {
        int nr;
        u32 msrs[KVM_NR_SHARED_MSRS];
};

struct kvm_shared_msrs {
        struct user_return_notifier urn;
        bool registered;
        struct kvm_shared_msr_values {
                u64 host;
                u64 curr;
        } values[KVM_NR_SHARED_MSRS];
};

static struct kvm_shared_msrs_global __read_mostly shared_msrs_global;
static struct kvm_shared_msrs __percpu *shared_msrs;

struct kvm_stats_debugfs_item debugfs_entries[] = {
        { "pf_fixed", VCPU_STAT(pf_fixed) },
        { "pf_guest", VCPU_STAT(pf_guest) },
        { "tlb_flush", VCPU_STAT(tlb_flush) },
        { "invlpg", VCPU_STAT(invlpg) },
        { "exits", VCPU_STAT(exits) },
        { "io_exits", VCPU_STAT(io_exits) },
        { "mmio_exits", VCPU_STAT(mmio_exits) },
        { "signal_exits", VCPU_STAT(signal_exits) },
        { "irq_window", VCPU_STAT(irq_window_exits) },
        { "nmi_window", VCPU_STAT(nmi_window_exits) },
        { "halt_exits", VCPU_STAT(halt_exits) },
        { "halt_successful_poll", VCPU_STAT(halt_successful_poll) },
        { "halt_wakeup", VCPU_STAT(halt_wakeup) },
        { "hypercalls", VCPU_STAT(hypercalls) },
        { "request_irq", VCPU_STAT(request_irq_exits) },
        { "irq_exits", VCPU_STAT(irq_exits) },
        { "host_state_reload", VCPU_STAT(host_state_reload) },
        { "efer_reload", VCPU_STAT(efer_reload) },
        { "fpu_reload", VCPU_STAT(fpu_reload) },
        { "insn_emulation", VCPU_STAT(insn_emulation) },
        { "insn_emulation_fail", VCPU_STAT(insn_emulation_fail) },
        { "irq_injections", VCPU_STAT(irq_injections) },
        { "nmi_injections", VCPU_STAT(nmi_injections) },
        { "mmu_shadow_zapped", VM_STAT(mmu_shadow_zapped) },
        { "mmu_pte_write", VM_STAT(mmu_pte_write) },
        { "mmu_pte_updated", VM_STAT(mmu_pte_updated) },
        { "mmu_pde_zapped", VM_STAT(mmu_pde_zapped) },
        { "mmu_flooded", VM_STAT(mmu_flooded) },
        { "mmu_recycled", VM_STAT(mmu_recycled) },
        { "mmu_cache_miss", VM_STAT(mmu_cache_miss) },
        { "mmu_unsync", VM_STAT(mmu_unsync) },
        { "remote_tlb_flush", VM_STAT(remote_tlb_flush) },
        { "largepages", VM_STAT(lpages) },
        { NULL }
};

u64 __read_mostly host_xcr0;

static int emulator_fix_hypercall(struct x86_emulate_ctxt *ctxt);

static inline void kvm_async_pf_hash_reset(struct kvm_vcpu *vcpu)
{
        int i;
        for (i = 0; i < roundup_pow_of_two(ASYNC_PF_PER_VCPU); i++)
                vcpu->arch.apf.gfns[i] = ~0;
}

static void kvm_on_user_return(struct user_return_notifier *urn)
{
        unsigned slot;
        struct kvm_shared_msrs *locals
                = container_of(urn, struct kvm_shared_msrs, urn);
        struct kvm_shared_msr_values *values;

        for (slot = 0; slot < shared_msrs_global.nr; ++slot) {
                values = &locals->values[slot];
                if (values->host != values->curr) {
                        wrmsrl(shared_msrs_global.msrs[slot], values->host);
                        values->curr = values->host;
                }
        }
        locals->registered = false;
        user_return_notifier_unregister(urn);
}

static void shared_msr_update(unsigned slot, u32 msr)
{
        u64 value;
        unsigned int cpu = smp_processor_id();
        struct kvm_shared_msrs *smsr = per_cpu_ptr(shared_msrs, cpu);

        /* only read, and nobody should modify it at this time,
         * so don't need lock */
        if (slot >= shared_msrs_global.nr) {
                printk(KERN_ERR "kvm: invalid MSR slot!");
                return;
        }
        rdmsrl_safe(msr, &value);
        smsr->values[slot].host = value;
        smsr->values[slot].curr = value;
}

void kvm_define_shared_msr(unsigned slot, u32 msr)
{
        BUG_ON(slot >= KVM_NR_SHARED_MSRS);
        if (slot >= shared_msrs_global.nr)
                shared_msrs_global.nr = slot + 1;
        shared_msrs_global.msrs[slot] = msr;
        /* we need ensured the shared_msr_global have been updated */
        smp_wmb();
}
EXPORT_SYMBOL_GPL(kvm_define_shared_msr);

static void kvm_shared_msr_cpu_online(void)
{
        unsigned i;

        for (i = 0; i < shared_msrs_global.nr; ++i)
                shared_msr_update(i, shared_msrs_global.msrs[i]);
}

int kvm_set_shared_msr(unsigned slot, u64 value, u64 mask)
{
        unsigned int cpu = smp_processor_id();
        struct kvm_shared_msrs *smsr = per_cpu_ptr(shared_msrs, cpu);
        int err;

        if (((value ^ smsr->values[slot].curr) & mask) == 0)
                return 0;
        smsr->values[slot].curr = value;
        err = wrmsrl_safe(shared_msrs_global.msrs[slot], value);
        if (err)
                return 1;

        if (!smsr->registered) {
                smsr->urn.on_user_return = kvm_on_user_return;
                user_return_notifier_register(&smsr->urn);
                smsr->registered = true;
        }
        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_shared_msr);

static void drop_user_return_notifiers(void)
{
        unsigned int cpu = smp_processor_id();
        struct kvm_shared_msrs *smsr = per_cpu_ptr(shared_msrs, cpu);

        if (smsr->registered)
                kvm_on_user_return(&smsr->urn);
}

u64 kvm_get_apic_base(struct kvm_vcpu *vcpu)
{
        return vcpu->arch.apic_base;
}
EXPORT_SYMBOL_GPL(kvm_get_apic_base);

int kvm_set_apic_base(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
        u64 old_state = vcpu->arch.apic_base &
                (MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE);
        u64 new_state = msr_info->data &
                (MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE);
        u64 reserved_bits = ((~0ULL) << cpuid_maxphyaddr(vcpu)) |
                0x2ff | (guest_cpuid_has_x2apic(vcpu) ? 0 : X2APIC_ENABLE);

        if (!msr_info->host_initiated &&
            ((msr_info->data & reserved_bits) != 0 ||
             new_state == X2APIC_ENABLE ||
             (new_state == MSR_IA32_APICBASE_ENABLE &&
              old_state == (MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE)) ||
             (new_state == (MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE) &&
              old_state == 0)))
                return 1;

        kvm_lapic_set_base(vcpu, msr_info->data);
        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_apic_base);

asmlinkage __visible void kvm_spurious_fault(void)
{
        /* Fault while not rebooting.  We want the trace. */
        BUG();
}
EXPORT_SYMBOL_GPL(kvm_spurious_fault);

#define EXCPT_BENIGN            0
#define EXCPT_CONTRIBUTORY      1
#define EXCPT_PF                2

static int exception_class(int vector)
{
        switch (vector) {
        case PF_VECTOR:
                return EXCPT_PF;
        case DE_VECTOR:
        case TS_VECTOR:
        case NP_VECTOR:
        case SS_VECTOR:
        case GP_VECTOR:
                return EXCPT_CONTRIBUTORY;
        default:
                break;
        }
        return EXCPT_BENIGN;
}

#define EXCPT_FAULT             0
#define EXCPT_TRAP              1
#define EXCPT_ABORT             2
#define EXCPT_INTERRUPT         3

static int exception_type(int vector)
{
        unsigned int mask;

        if (WARN_ON(vector > 31 || vector == NMI_VECTOR))
                return EXCPT_INTERRUPT;

        mask = 1 << vector;

        /* #DB is trap, as instruction watchpoints are handled elsewhere */
        if (mask & ((1 << DB_VECTOR) | (1 << BP_VECTOR) | (1 << OF_VECTOR)))
                return EXCPT_TRAP;

        if (mask & ((1 << DF_VECTOR) | (1 << MC_VECTOR)))
                return EXCPT_ABORT;

        /* Reserved exceptions will result in fault */
        return EXCPT_FAULT;
}

static void kvm_multiple_exception(struct kvm_vcpu *vcpu,
                unsigned nr, bool has_error, u32 error_code,
                bool reinject)
{
        u32 prev_nr;
        int class1, class2;

        kvm_make_request(KVM_REQ_EVENT, vcpu);

        if (!vcpu->arch.exception.pending) {
        queue:
                if (has_error && !is_protmode(vcpu))
                        has_error = false;
                vcpu->arch.exception.pending = true;
                vcpu->arch.exception.has_error_code = has_error;
                vcpu->arch.exception.nr = nr;
                vcpu->arch.exception.error_code = error_code;
                vcpu->arch.exception.reinject = reinject;
                return;
        }

        /* to check exception */
        prev_nr = vcpu->arch.exception.nr;
        if (prev_nr == DF_VECTOR) {
                /* triple fault -> shutdown */
                kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
                return;
        }
        class1 = exception_class(prev_nr);
        class2 = exception_class(nr);
        if ((class1 == EXCPT_CONTRIBUTORY && class2 == EXCPT_CONTRIBUTORY)
                || (class1 == EXCPT_PF && class2 != EXCPT_BENIGN)) {
                /* generate double fault per SDM Table 5-5 */
                vcpu->arch.exception.pending = true;
                vcpu->arch.exception.has_error_code = true;
                vcpu->arch.exception.nr = DF_VECTOR;
                vcpu->arch.exception.error_code = 0;
        } else
                /* replace previous exception with a new one in a hope
                   that instruction re-execution will regenerate lost
                   exception */
                goto queue;
}

void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr)
{
        kvm_multiple_exception(vcpu, nr, false, 0, false);
}
EXPORT_SYMBOL_GPL(kvm_queue_exception);

void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned nr)
{
        kvm_multiple_exception(vcpu, nr, false, 0, true);
}
EXPORT_SYMBOL_GPL(kvm_requeue_exception);

void kvm_complete_insn_gp(struct kvm_vcpu *vcpu, int err)
{
        if (err)
                kvm_inject_gp(vcpu, 0);
        else
                kvm_x86_ops->skip_emulated_instruction(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_complete_insn_gp);

void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault)
{
        ++vcpu->stat.pf_guest;
        vcpu->arch.cr2 = fault->address;
        kvm_queue_exception_e(vcpu, PF_VECTOR, fault->error_code);
}
EXPORT_SYMBOL_GPL(kvm_inject_page_fault);

static bool kvm_propagate_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault)
{
        if (mmu_is_nested(vcpu) && !fault->nested_page_fault)
                vcpu->arch.nested_mmu.inject_page_fault(vcpu, fault);
        else
                vcpu->arch.mmu.inject_page_fault(vcpu, fault);

        return fault->nested_page_fault;
}

void kvm_inject_nmi(struct kvm_vcpu *vcpu)
{
        atomic_inc(&vcpu->arch.nmi_queued);
        kvm_make_request(KVM_REQ_NMI, vcpu);
}
EXPORT_SYMBOL_GPL(kvm_inject_nmi);

void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code)
{
        kvm_multiple_exception(vcpu, nr, true, error_code, false);
}
EXPORT_SYMBOL_GPL(kvm_queue_exception_e);

void kvm_requeue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code)
{
        kvm_multiple_exception(vcpu, nr, true, error_code, true);
}
EXPORT_SYMBOL_GPL(kvm_requeue_exception_e);

/*
 * Checks if cpl <= required_cpl; if true, return true.  Otherwise queue
 * a #GP and return false.
 */
bool kvm_require_cpl(struct kvm_vcpu *vcpu, int required_cpl)
{
        if (kvm_x86_ops->get_cpl(vcpu) <= required_cpl)
                return true;
        kvm_queue_exception_e(vcpu, GP_VECTOR, 0);
        return false;
}
EXPORT_SYMBOL_GPL(kvm_require_cpl);

bool kvm_require_dr(struct kvm_vcpu *vcpu, int dr)
{
        if ((dr != 4 && dr != 5) || !kvm_read_cr4_bits(vcpu, X86_CR4_DE))
                return true;

        kvm_queue_exception(vcpu, UD_VECTOR);
        return false;
}
EXPORT_SYMBOL_GPL(kvm_require_dr);

/*
 * This function will be used to read from the physical memory of the currently
 * running guest. The difference to kvm_vcpu_read_guest_page is that this function
 * can read from guest physical or from the guest's guest physical memory.
 */
int kvm_read_guest_page_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
                            gfn_t ngfn, void *data, int offset, int len,
                            u32 access)
{
        struct x86_exception exception;
        gfn_t real_gfn;
        gpa_t ngpa;

        ngpa     = gfn_to_gpa(ngfn);
        real_gfn = mmu->translate_gpa(vcpu, ngpa, access, &exception);
        if (real_gfn == UNMAPPED_GVA)
                return -EFAULT;

        real_gfn = gpa_to_gfn(real_gfn);

        return kvm_vcpu_read_guest_page(vcpu, real_gfn, data, offset, len);
}
EXPORT_SYMBOL_GPL(kvm_read_guest_page_mmu);

static int kvm_read_nested_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn,
                               void *data, int offset, int len, u32 access)
{
        return kvm_read_guest_page_mmu(vcpu, vcpu->arch.walk_mmu, gfn,
                                       data, offset, len, access);
}

/*
 * Load the pae pdptrs.  Return true is they are all valid.
 */
int load_pdptrs(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned long cr3)
{
        gfn_t pdpt_gfn = cr3 >> PAGE_SHIFT;
        unsigned offset = ((cr3 & (PAGE_SIZE-1)) >> 5) << 2;
        int i;
        int ret;
        u64 pdpte[ARRAY_SIZE(mmu->pdptrs)];

        ret = kvm_read_guest_page_mmu(vcpu, mmu, pdpt_gfn, pdpte,
                                      offset * sizeof(u64), sizeof(pdpte),
                                      PFERR_USER_MASK|PFERR_WRITE_MASK);
        if (ret < 0) {
                ret = 0;
                goto out;
        }
        for (i = 0; i < ARRAY_SIZE(pdpte); ++i) {
                if (is_present_gpte(pdpte[i]) &&
                    (pdpte[i] & vcpu->arch.mmu.rsvd_bits_mask[0][2])) {
                        ret = 0;
                        goto out;
                }
        }
        ret = 1;

        memcpy(mmu->pdptrs, pdpte, sizeof(mmu->pdptrs));
        __set_bit(VCPU_EXREG_PDPTR,
                  (unsigned long *)&vcpu->arch.regs_avail);
        __set_bit(VCPU_EXREG_PDPTR,
                  (unsigned long *)&vcpu->arch.regs_dirty);
out:

        return ret;
}
EXPORT_SYMBOL_GPL(load_pdptrs);

static bool pdptrs_changed(struct kvm_vcpu *vcpu)
{
        u64 pdpte[ARRAY_SIZE(vcpu->arch.walk_mmu->pdptrs)];
        bool changed = true;
        int offset;
        gfn_t gfn;
        int r;

        if (is_long_mode(vcpu) || !is_pae(vcpu))
                return false;

        if (!test_bit(VCPU_EXREG_PDPTR,
                      (unsigned long *)&vcpu->arch.regs_avail))
                return true;

        gfn = (kvm_read_cr3(vcpu) & ~31u) >> PAGE_SHIFT;
        offset = (kvm_read_cr3(vcpu) & ~31u) & (PAGE_SIZE - 1);
        r = kvm_read_nested_guest_page(vcpu, gfn, pdpte, offset, sizeof(pdpte),
                                       PFERR_USER_MASK | PFERR_WRITE_MASK);
        if (r < 0)
                goto out;
        changed = memcmp(pdpte, vcpu->arch.walk_mmu->pdptrs, sizeof(pdpte)) != 0;
out:

        return changed;
}

int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
{
        unsigned long old_cr0 = kvm_read_cr0(vcpu);
        unsigned long update_bits = X86_CR0_PG | X86_CR0_WP;

        cr0 |= X86_CR0_ET;

#ifdef CONFIG_X86_64
        if (cr0 & 0xffffffff00000000UL)
                return 1;
#endif

        cr0 &= ~CR0_RESERVED_BITS;

        if ((cr0 & X86_CR0_NW) && !(cr0 & X86_CR0_CD))
                return 1;

        if ((cr0 & X86_CR0_PG) && !(cr0 & X86_CR0_PE))
                return 1;

        if (!is_paging(vcpu) && (cr0 & X86_CR0_PG)) {
#ifdef CONFIG_X86_64
                if ((vcpu->arch.efer & EFER_LME)) {
                        int cs_db, cs_l;

                        if (!is_pae(vcpu))
                                return 1;
                        kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);
                        if (cs_l)
                                return 1;
                } else
#endif
                if (is_pae(vcpu) && !load_pdptrs(vcpu, vcpu->arch.walk_mmu,
                                                 kvm_read_cr3(vcpu)))
                        return 1;
        }

        if (!(cr0 & X86_CR0_PG) && kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE))
                return 1;

        kvm_x86_ops->set_cr0(vcpu, cr0);

        if ((cr0 ^ old_cr0) & X86_CR0_PG) {
                kvm_clear_async_pf_completion_queue(vcpu);
                kvm_async_pf_hash_reset(vcpu);
        }

        if ((cr0 ^ old_cr0) & update_bits)
                kvm_mmu_reset_context(vcpu);

        if ((cr0 ^ old_cr0) & X86_CR0_CD)
                kvm_zap_gfn_range(vcpu->kvm, 0, ~0ULL);

        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_cr0);

void kvm_lmsw(struct kvm_vcpu *vcpu, unsigned long msw)
{
        (void)kvm_set_cr0(vcpu, kvm_read_cr0_bits(vcpu, ~0x0eul) | (msw & 0x0f));
}
EXPORT_SYMBOL_GPL(kvm_lmsw);

static void kvm_load_guest_xcr0(struct kvm_vcpu *vcpu)
{
        if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE) &&
                        !vcpu->guest_xcr0_loaded) {
                /* kvm_set_xcr() also depends on this */
                xsetbv(XCR_XFEATURE_ENABLED_MASK, vcpu->arch.xcr0);
                vcpu->guest_xcr0_loaded = 1;
        }
}

static void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu)
{
        if (vcpu->guest_xcr0_loaded) {
                if (vcpu->arch.xcr0 != host_xcr0)
                        xsetbv(XCR_XFEATURE_ENABLED_MASK, host_xcr0);
                vcpu->guest_xcr0_loaded = 0;
        }
}

static int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
{
        u64 xcr0 = xcr;
        u64 old_xcr0 = vcpu->arch.xcr0;
        u64 valid_bits;

        /* Only support XCR_XFEATURE_ENABLED_MASK(xcr0) now  */
        if (index != XCR_XFEATURE_ENABLED_MASK)
                return 1;
        if (!(xcr0 & XSTATE_FP))
                return 1;
        if ((xcr0 & XSTATE_YMM) && !(xcr0 & XSTATE_SSE))
                return 1;

        /*
         * Do not allow the guest to set bits that we do not support
         * saving.  However, xcr0 bit 0 is always set, even if the
         * emulated CPU does not support XSAVE (see fx_init).
         */
        valid_bits = vcpu->arch.guest_supported_xcr0 | XSTATE_FP;
        if (xcr0 & ~valid_bits)
                return 1;

        if ((!(xcr0 & XSTATE_BNDREGS)) != (!(xcr0 & XSTATE_BNDCSR)))
                return 1;

        if (xcr0 & XSTATE_AVX512) {
                if (!(xcr0 & XSTATE_YMM))
                        return 1;
                if ((xcr0 & XSTATE_AVX512) != XSTATE_AVX512)
                        return 1;
        }
        kvm_put_guest_xcr0(vcpu);
        vcpu->arch.xcr0 = xcr0;

        if ((xcr0 ^ old_xcr0) & XSTATE_EXTEND_MASK)
                kvm_update_cpuid(vcpu);
        return 0;
}

int kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
{
        if (kvm_x86_ops->get_cpl(vcpu) != 0 ||
            __kvm_set_xcr(vcpu, index, xcr)) {
                kvm_inject_gp(vcpu, 0);
                return 1;
        }
        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_xcr);

int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
{
        unsigned long old_cr4 = kvm_read_cr4(vcpu);
        unsigned long pdptr_bits = X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PAE |
                                   X86_CR4_SMEP | X86_CR4_SMAP;

        if (cr4 & CR4_RESERVED_BITS)
                return 1;

        if (!guest_cpuid_has_xsave(vcpu) && (cr4 & X86_CR4_OSXSAVE))
                return 1;

        if (!guest_cpuid_has_smep(vcpu) && (cr4 & X86_CR4_SMEP))
                return 1;

        if (!guest_cpuid_has_smap(vcpu) && (cr4 & X86_CR4_SMAP))
                return 1;

        if (!guest_cpuid_has_fsgsbase(vcpu) && (cr4 & X86_CR4_FSGSBASE))
                return 1;

        if (is_long_mode(vcpu)) {
                if (!(cr4 & X86_CR4_PAE))
                        return 1;
        } else if (is_paging(vcpu) && (cr4 & X86_CR4_PAE)
                   && ((cr4 ^ old_cr4) & pdptr_bits)
                   && !load_pdptrs(vcpu, vcpu->arch.walk_mmu,
                                   kvm_read_cr3(vcpu)))
                return 1;

        if ((cr4 & X86_CR4_PCIDE) && !(old_cr4 & X86_CR4_PCIDE)) {
                if (!guest_cpuid_has_pcid(vcpu))
                        return 1;

                /* PCID can not be enabled when cr3[11:0]!=000H or EFER.LMA=0 */
                if ((kvm_read_cr3(vcpu) & X86_CR3_PCID_MASK) || !is_long_mode(vcpu))
                        return 1;
        }

        if (kvm_x86_ops->set_cr4(vcpu, cr4))
                return 1;

        if (((cr4 ^ old_cr4) & pdptr_bits) ||
            (!(cr4 & X86_CR4_PCIDE) && (old_cr4 & X86_CR4_PCIDE)))
                kvm_mmu_reset_context(vcpu);

        if ((cr4 ^ old_cr4) & X86_CR4_OSXSAVE)
                kvm_update_cpuid(vcpu);

        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_cr4);

int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
{
#ifdef CONFIG_X86_64
        cr3 &= ~CR3_PCID_INVD;
#endif

        if (cr3 == kvm_read_cr3(vcpu) && !pdptrs_changed(vcpu)) {
                kvm_mmu_sync_roots(vcpu);
                kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
                return 0;
        }

        if (is_long_mode(vcpu)) {
                if (cr3 & CR3_L_MODE_RESERVED_BITS)
                        return 1;
        } else if (is_pae(vcpu) && is_paging(vcpu) &&
                   !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))
                return 1;

        vcpu->arch.cr3 = cr3;
        __set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail);
        kvm_mmu_new_cr3(vcpu);
        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_cr3);

int kvm_set_cr8(struct kvm_vcpu *vcpu, unsigned long cr8)
{
        if (cr8 & CR8_RESERVED_BITS)
                return 1;
        if (irqchip_in_kernel(vcpu->kvm))
                kvm_lapic_set_tpr(vcpu, cr8);
        else
                vcpu->arch.cr8 = cr8;
        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_cr8);

unsigned long kvm_get_cr8(struct kvm_vcpu *vcpu)
{
        if (irqchip_in_kernel(vcpu->kvm))
                return kvm_lapic_get_cr8(vcpu);
        else
                return vcpu->arch.cr8;
}
EXPORT_SYMBOL_GPL(kvm_get_cr8);

static void kvm_update_dr0123(struct kvm_vcpu *vcpu)
{
        int i;

        if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) {
                for (i = 0; i < KVM_NR_DB_REGS; i++)
                        vcpu->arch.eff_db[i] = vcpu->arch.db[i];
                vcpu->arch.switch_db_regs |= KVM_DEBUGREG_RELOAD;
        }
}

static void kvm_update_dr6(struct kvm_vcpu *vcpu)
{
        if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
                kvm_x86_ops->set_dr6(vcpu, vcpu->arch.dr6);
}

static void kvm_update_dr7(struct kvm_vcpu *vcpu)
{
        unsigned long dr7;

        if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
                dr7 = vcpu->arch.guest_debug_dr7;
        else
                dr7 = vcpu->arch.dr7;
        kvm_x86_ops->set_dr7(vcpu, dr7);
        vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_BP_ENABLED;
        if (dr7 & DR7_BP_EN_MASK)
                vcpu->arch.switch_db_regs |= KVM_DEBUGREG_BP_ENABLED;
}

static u64 kvm_dr6_fixed(struct kvm_vcpu *vcpu)
{
        u64 fixed = DR6_FIXED_1;

        if (!guest_cpuid_has_rtm(vcpu))
                fixed |= DR6_RTM;
        return fixed;
}

static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
{
        switch (dr) {
        case 0 ... 3:
                vcpu->arch.db[dr] = val;
                if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
                        vcpu->arch.eff_db[dr] = val;
                break;
        case 4:
                /* fall through */
        case 6:
                if (val & 0xffffffff00000000ULL)
                        return -1; /* #GP */
                vcpu->arch.dr6 = (val & DR6_VOLATILE) | kvm_dr6_fixed(vcpu);
                kvm_update_dr6(vcpu);
                break;
        case 5:
                /* fall through */
        default: /* 7 */
                if (val & 0xffffffff00000000ULL)
                        return -1; /* #GP */
                vcpu->arch.dr7 = (val & DR7_VOLATILE) | DR7_FIXED_1;
                kvm_update_dr7(vcpu);
                break;
        }

        return 0;
}

int kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
{
        if (__kvm_set_dr(vcpu, dr, val)) {
                kvm_inject_gp(vcpu, 0);
                return 1;
        }
        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_dr);

int kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val)
{
        switch (dr) {
        case 0 ... 3:
                *val = vcpu->arch.db[dr];
                break;
        case 4:
                /* fall through */
        case 6:
                if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
                        *val = vcpu->arch.dr6;
                else
                        *val = kvm_x86_ops->get_dr6(vcpu);
                break;
        case 5:
                /* fall through */
        default: /* 7 */
                *val = vcpu->arch.dr7;
                break;
        }
        return 0;
}
EXPORT_SYMBOL_GPL(kvm_get_dr);

bool kvm_rdpmc(struct kvm_vcpu *vcpu)
{
        u32 ecx = kvm_register_read(vcpu, VCPU_REGS_RCX);
        u64 data;
        int err;

        err = kvm_pmu_rdpmc(vcpu, ecx, &data);
        if (err)
                return err;
        kvm_register_write(vcpu, VCPU_REGS_RAX, (u32)data);
        kvm_register_write(vcpu, VCPU_REGS_RDX, data >> 32);
        return err;
}
EXPORT_SYMBOL_GPL(kvm_rdpmc);

/*
 * List of msr numbers which we expose to userspace through KVM_GET_MSRS
 * and KVM_SET_MSRS, and KVM_GET_MSR_INDEX_LIST.
 *
 * This list is modified at module load time to reflect the
 * capabilities of the host cpu. This capabilities test skips MSRs that are
 * kvm-specific. Those are put in emulated_msrs; filtering of emulated_msrs
 * may depend on host virtualization features rather than host cpu features.
 */

static u32 msrs_to_save[] = {
        MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
        MSR_STAR,
#ifdef CONFIG_X86_64
        MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR,
#endif
        MSR_IA32_TSC, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA,
        MSR_IA32_FEATURE_CONTROL, MSR_IA32_BNDCFGS
};

static unsigned num_msrs_to_save;

static u32 emulated_msrs[] = {
        MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK,
        MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW,
        HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,
        HV_X64_MSR_TIME_REF_COUNT, HV_X64_MSR_REFERENCE_TSC,
        HV_X64_MSR_APIC_ASSIST_PAGE, MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIME,
        MSR_KVM_PV_EOI_EN,

        MSR_IA32_TSC_ADJUST,
        MSR_IA32_TSCDEADLINE,
        MSR_IA32_MISC_ENABLE,
        MSR_IA32_MCG_STATUS,
        MSR_IA32_MCG_CTL,
        MSR_IA32_SMBASE,
};

static unsigned num_emulated_msrs;

bool kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer)
{
        if (efer & efer_reserved_bits)
                return false;

        if (efer & EFER_FFXSR) {
                struct kvm_cpuid_entry2 *feat;

                feat = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
                if (!feat || !(feat->edx & bit(X86_FEATURE_FXSR_OPT)))
                        return false;
        }

        if (efer & EFER_SVME) {
                struct kvm_cpuid_entry2 *feat;

                feat = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
                if (!feat || !(feat->ecx & bit(X86_FEATURE_SVM)))
                        return false;
        }

        return true;
}
EXPORT_SYMBOL_GPL(kvm_valid_efer);

static int set_efer(struct kvm_vcpu *vcpu, u64 efer)
{
        u64 old_efer = vcpu->arch.efer;

        if (!kvm_valid_efer(vcpu, efer))
                return 1;

        if (is_paging(vcpu)
            && (vcpu->arch.efer & EFER_LME) != (efer & EFER_LME))
                return 1;

        efer &= ~EFER_LMA;
        efer |= vcpu->arch.efer & EFER_LMA;

        kvm_x86_ops->set_efer(vcpu, efer);

        /* Update reserved bits */
        if ((efer ^ old_efer) & EFER_NX)
                kvm_mmu_reset_context(vcpu);

        return 0;
}

void kvm_enable_efer_bits(u64 mask)
{
       efer_reserved_bits &= ~mask;
}
EXPORT_SYMBOL_GPL(kvm_enable_efer_bits);

/*
 * Writes msr value into into the appropriate "register".
 * Returns 0 on success, non-0 otherwise.
 * Assumes vcpu_load() was already called.
 */
int kvm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
{
        switch (msr->index) {
        case MSR_FS_BASE:
        case MSR_GS_BASE:
        case MSR_KERNEL_GS_BASE:
        case MSR_CSTAR:
        case MSR_LSTAR:
                if (is_noncanonical_address(msr->data))
                        return 1;
                break;
        case MSR_IA32_SYSENTER_EIP:
        case MSR_IA32_SYSENTER_ESP:
                /*
                 * IA32_SYSENTER_ESP and IA32_SYSENTER_EIP cause #GP if
                 * non-canonical address is written on Intel but not on
                 * AMD (which ignores the top 32-bits, because it does
                 * not implement 64-bit SYSENTER).
                 *
                 * 64-bit code should hence be able to write a non-canonical
                 * value on AMD.  Making the address canonical ensures that
                 * vmentry does not fail on Intel after writing a non-canonical
                 * value, and that something deterministic happens if the guest
                 * invokes 64-bit SYSENTER.
                 */
                msr->data = get_canonical(msr->data);
        }
        return kvm_x86_ops->set_msr(vcpu, msr);
}
EXPORT_SYMBOL_GPL(kvm_set_msr);

/*
 * Adapt set_msr() to msr_io()'s calling convention
 */
static int do_get_msr(struct kvm_vcpu *vcpu, unsigned index, u64 *data)
{
        struct msr_data msr;
        int r;

        msr.index = index;
        msr.host_initiated = true;
        r = kvm_get_msr(vcpu, &msr);
        if (r)
                return r;

        *data = msr.data;
        return 0;
}

static int do_set_msr(struct kvm_vcpu *vcpu, unsigned index, u64 *data)
{
        struct msr_data msr;

        msr.data = *data;
        msr.index = index;
        msr.host_initiated = true;
        return kvm_set_msr(vcpu, &msr);
}

#ifdef CONFIG_X86_64
struct pvclock_gtod_data {
        seqcount_t      seq;

        struct { /* extract of a clocksource struct */
                int vclock_mode;
                cycle_t cycle_last;
                cycle_t mask;
                u32     mult;
                u32     shift;
        } clock;

        u64             boot_ns;
        u64             nsec_base;
};

static struct pvclock_gtod_data pvclock_gtod_data;

static void update_pvclock_gtod(struct timekeeper *tk)
{
        struct pvclock_gtod_data *vdata = &pvclock_gtod_data;
        u64 boot_ns;

        boot_ns = ktime_to_ns(ktime_add(tk->tkr_mono.base, tk->offs_boot));

        write_seqcount_begin(&vdata->seq);

        /* copy pvclock gtod data */
        vdata->clock.vclock_mode        = tk->tkr_mono.clock->archdata.vclock_mode;
        vdata->clock.cycle_last         = tk->tkr_mono.cycle_last;
        vdata->clock.mask               = tk->tkr_mono.mask;
        vdata->clock.mult               = tk->tkr_mono.mult;
        vdata->clock.shift              = tk->tkr_mono.shift;

        vdata->boot_ns                  = boot_ns;
        vdata->nsec_base                = tk->tkr_mono.xtime_nsec;

        write_seqcount_end(&vdata->seq);
}
#endif

void kvm_set_pending_timer(struct kvm_vcpu *vcpu)
{
        /*
         * Note: KVM_REQ_PENDING_TIMER is implicitly checked in
         * vcpu_enter_guest.  This function is only called from
         * the physical CPU that is running vcpu.
         */
        kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);
}

static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock)
{
        int version;
        int r;
        struct pvclock_wall_clock wc;
        struct timespec boot;

        if (!wall_clock)
                return;

        r = kvm_read_guest(kvm, wall_clock, &version, sizeof(version));
        if (r)
                return;

        if (version & 1)
                ++version;  /* first time write, random junk */

        ++version;

        kvm_write_guest(kvm, wall_clock, &version, sizeof(version));

        /*
         * The guest calculates current wall clock time by adding
         * system time (updated by kvm_guest_time_update below) to the
         * wall clock specified here.  guest system time equals host
         * system time for us, thus we must fill in host boot time here.
         */
        getboottime(&boot);

        if (kvm->arch.kvmclock_offset) {
                struct timespec ts = ns_to_timespec(kvm->arch.kvmclock_offset);
                boot = timespec_sub(boot, ts);
        }
        wc.sec = boot.tv_sec;
        wc.nsec = boot.tv_nsec;
        wc.version = version;

        kvm_write_guest(kvm, wall_clock, &wc, sizeof(wc));

        version++;
        kvm_write_guest(kvm, wall_clock, &version, sizeof(version));
}

static uint32_t div_frac(uint32_t dividend, uint32_t divisor)
{
        uint32_t quotient, remainder;

        /* Don't try to replace with do_div(), this one calculates
         * "(dividend << 32) / divisor" */
        __asm__ ( "divl %4"
                  : "=a" (quotient), "=d" (remainder)
                  : "0" (0), "1" (dividend), "r" (divisor) );
        return quotient;
}

static void kvm_get_time_scale(uint32_t scaled_khz, uint32_t base_khz,
                               s8 *pshift, u32 *pmultiplier)
{
        uint64_t scaled64;
        int32_t  shift = 0;
        uint64_t tps64;
        uint32_t tps32;

        tps64 = base_khz * 1000LL;
        scaled64 = scaled_khz * 1000LL;
        while (tps64 > scaled64*2 || tps64 & 0xffffffff00000000ULL) {
                tps64 >>= 1;
                shift--;
        }

        tps32 = (uint32_t)tps64;
        while (tps32 <= scaled64 || scaled64 & 0xffffffff00000000ULL) {
                if (scaled64 & 0xffffffff00000000ULL || tps32 & 0x80000000)
                        scaled64 >>= 1;
                else
                        tps32 <<= 1;
                shift++;
        }

        *pshift = shift;
        *pmultiplier = div_frac(scaled64, tps32);

        pr_debug("%s: base_khz %u => %u, shift %d, mul %u\n",
                 __func__, base_khz, scaled_khz, shift, *pmultiplier);
}

#ifdef CONFIG_X86_64
static atomic_t kvm_guest_has_master_clock = ATOMIC_INIT(0);
#endif

static DEFINE_PER_CPU(unsigned long, cpu_tsc_khz);
static unsigned long max_tsc_khz;

static inline u64 nsec_to_cycles(struct kvm_vcpu *vcpu, u64 nsec)
{
        return pvclock_scale_delta(nsec, vcpu->arch.virtual_tsc_mult,
                                   vcpu->arch.virtual_tsc_shift);
}

static u32 adjust_tsc_khz(u32 khz, s32 ppm)
{
        u64 v = (u64)khz * (1000000 + ppm);
        do_div(v, 1000000);
        return v;
}

static void kvm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 this_tsc_khz)
{
        u32 thresh_lo, thresh_hi;
        int use_scaling = 0;

        /* tsc_khz can be zero if TSC calibration fails */
        if (this_tsc_khz == 0)
                return;

        /* Compute a scale to convert nanoseconds in TSC cycles */
        kvm_get_time_scale(this_tsc_khz, NSEC_PER_SEC / 1000,
                           &vcpu->arch.virtual_tsc_shift,
                           &vcpu->arch.virtual_tsc_mult);
        vcpu->arch.virtual_tsc_khz = this_tsc_khz;

        /*
         * Compute the variation in TSC rate which is acceptable
         * within the range of tolerance and decide if the
         * rate being applied is within that bounds of the hardware
         * rate.  If so, no scaling or compensation need be done.
         */
        thresh_lo = adjust_tsc_khz(tsc_khz, -tsc_tolerance_ppm);
        thresh_hi = adjust_tsc_khz(tsc_khz, tsc_tolerance_ppm);
        if (this_tsc_khz < thresh_lo || this_tsc_khz > thresh_hi) {
                pr_debug("kvm: requested TSC rate %u falls outside tolerance [%u,%u]\n", this_tsc_khz, thresh_lo, thresh_hi);
                use_scaling = 1;
        }
        kvm_x86_ops->set_tsc_khz(vcpu, this_tsc_khz, use_scaling);
}

static u64 compute_guest_tsc(struct kvm_vcpu *vcpu, s64 kernel_ns)
{
        u64 tsc = pvclock_scale_delta(kernel_ns-vcpu->arch.this_tsc_nsec,
                                      vcpu->arch.virtual_tsc_mult,
                                      vcpu->arch.virtual_tsc_shift);
        tsc += vcpu->arch.this_tsc_write;
        return tsc;
}

static void kvm_track_tsc_matching(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_X86_64
        bool vcpus_matched;
        struct kvm_arch *ka = &vcpu->kvm->arch;
        struct pvclock_gtod_data *gtod = &pvclock_gtod_data;

        vcpus_matched = (ka->nr_vcpus_matched_tsc + 1 ==
                         atomic_read(&vcpu->kvm->online_vcpus));

        /*
         * Once the masterclock is enabled, always perform request in
         * order to update it.
         *
         * In order to enable masterclock, the host clocksource must be TSC
         * and the vcpus need to have matched TSCs.  When that happens,
         * perform request to enable masterclock.
         */
        if (ka->use_master_clock ||
            (gtod->clock.vclock_mode == VCLOCK_TSC && vcpus_matched))
                kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);

        trace_kvm_track_tsc(vcpu->vcpu_id, ka->nr_vcpus_matched_tsc,
                            atomic_read(&vcpu->kvm->online_vcpus),
                            ka->use_master_clock, gtod->clock.vclock_mode);
#endif
}

static void update_ia32_tsc_adjust_msr(struct kvm_vcpu *vcpu, s64 offset)
{
        u64 curr_offset = kvm_x86_ops->read_tsc_offset(vcpu);
        vcpu->arch.ia32_tsc_adjust_msr += offset - curr_offset;
}

void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr)
{
        struct kvm *kvm = vcpu->kvm;
        u64 offset, ns, elapsed;
        unsigned long flags;
        s64 usdiff;
        bool matched;
        bool already_matched;
        u64 data = msr->data;

        raw_spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags);
        offset = kvm_x86_ops->compute_tsc_offset(vcpu, data);
        ns = get_kernel_ns();
        elapsed = ns - kvm->arch.last_tsc_nsec;

        if (vcpu->arch.virtual_tsc_khz) {
                int faulted = 0;

                /* n.b - signed multiplication and division required */
                usdiff = data - kvm->arch.last_tsc_write;
#ifdef CONFIG_X86_64
                usdiff = (usdiff * 1000) / vcpu->arch.virtual_tsc_khz;
#else
                /* do_div() only does unsigned */
                asm("1: idivl %[divisor]\n"
                    "2: xor %%edx, %%edx\n"
                    "   movl $0, %[faulted]\n"
                    "3:\n"
                    ".section .fixup,\"ax\"\n"
                    "4: movl $1, %[faulted]\n"
                    "   jmp  3b\n"
                    ".previous\n"

                _ASM_EXTABLE(1b, 4b)

                : "=A"(usdiff), [faulted] "=r" (faulted)
                : "A"(usdiff * 1000), [divisor] "rm"(vcpu->arch.virtual_tsc_khz));

#endif
                do_div(elapsed, 1000);
                usdiff -= elapsed;
                if (usdiff < 0)
                        usdiff = -usdiff;

                /* idivl overflow => difference is larger than USEC_PER_SEC */
                if (faulted)
                        usdiff = USEC_PER_SEC;
        } else
                usdiff = USEC_PER_SEC; /* disable TSC match window below */

        /*
         * Special case: TSC write with a small delta (1 second) of virtual
         * cycle time against real time is interpreted as an attempt to
         * synchronize the CPU.
         *
         * For a reliable TSC, we can match TSC offsets, and for an unstable
         * TSC, we add elapsed time in this computation.  We could let the
         * compensation code attempt to catch up if we fall behind, but
         * it's better to try to match offsets from the beginning.
         */
        if (usdiff < USEC_PER_SEC &&
            vcpu->arch.virtual_tsc_khz == kvm->arch.last_tsc_khz) {
                if (!check_tsc_unstable()) {
                        offset = kvm->arch.cur_tsc_offset;
                        pr_debug("kvm: matched tsc offset for %llu\n", data);
                } else {
                        u64 delta = nsec_to_cycles(vcpu, elapsed);
                        data += delta;
                        offset = kvm_x86_ops->compute_tsc_offset(vcpu, data);
                        pr_debug("kvm: adjusted tsc offset by %llu\n", delta);
                }
                matched = true;
                already_matched = (vcpu->arch.this_tsc_generation == kvm->arch.cur_tsc_generation);
        } else {
                /*
                 * We split periods of matched TSC writes into generations.
                 * For each generation, we track the original measured
                 * nanosecond time, offset, and write, so if TSCs are in
                 * sync, we can match exact offset, and if not, we can match
                 * exact software computation in compute_guest_tsc()
                 *
                 * These values are tracked in kvm->arch.cur_xxx variables.
                 */
                kvm->arch.cur_tsc_generation++;
                kvm->arch.cur_tsc_nsec = ns;
                kvm->arch.cur_tsc_write = data;
                kvm->arch.cur_tsc_offset = offset;
                matched = false;
                pr_debug("kvm: new tsc generation %llu, clock %llu\n",
                         kvm->arch.cur_tsc_generation, data);
        }

        /*
         * We also track th most recent recorded KHZ, write and time to
         * allow the matching interval to be extended at each write.
         */
        kvm->arch.last_tsc_nsec = ns;
        kvm->arch.last_tsc_write = data;
        kvm->arch.last_tsc_khz = vcpu->arch.virtual_tsc_khz;

        vcpu->arch.last_guest_tsc = data;

        /* Keep track of which generation this VCPU has synchronized to */
        vcpu->arch.this_tsc_generation = kvm->arch.cur_tsc_generation;
        vcpu->arch.this_tsc_nsec = kvm->arch.cur_tsc_nsec;
        vcpu->arch.this_tsc_write = kvm->arch.cur_tsc_write;

        if (guest_cpuid_has_tsc_adjust(vcpu) && !msr->host_initiated)
                update_ia32_tsc_adjust_msr(vcpu, offset);
        kvm_x86_ops->write_tsc_offset(vcpu, offset);
        raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags);

        spin_lock(&kvm->arch.pvclock_gtod_sync_lock);
        if (!matched) {
                kvm->arch.nr_vcpus_matched_tsc = 0;
        } else if (!already_matched) {
                kvm->arch.nr_vcpus_matched_tsc++;
        }

        kvm_track_tsc_matching(vcpu);
        spin_unlock(&kvm->arch.pvclock_gtod_sync_lock);
}

EXPORT_SYMBOL_GPL(kvm_write_tsc);

#ifdef CONFIG_X86_64

static cycle_t read_tsc(void)
{
        cycle_t ret;
        u64 last;

        /*
         * Empirically, a fence (of type that depends on the CPU)
         * before rdtsc is enough to ensure that rdtsc is ordered
         * with respect to loads.  The various CPU manuals are unclear
         * as to whether rdtsc can be reordered with later loads,
         * but no one has ever seen it happen.
         */
        rdtsc_barrier();
        ret = (cycle_t)vget_cycles();

        last = pvclock_gtod_data.clock.cycle_last;

        if (likely(ret >= last))
                return ret;

        /*
         * GCC likes to generate cmov here, but this branch is extremely
         * predictable (it's just a funciton of time and the likely is
         * very likely) and there's a data dependence, so force GCC
         * to generate a branch instead.  I don't barrier() because
         * we don't actually need a barrier, and if this function
         * ever gets inlined it will generate worse code.
         */
        asm volatile ("");
        return last;
}

static inline u64 vgettsc(cycle_t *cycle_now)
{
        long v;
        struct pvclock_gtod_data *gtod = &pvclock_gtod_data;

        *cycle_now = read_tsc();

        v = (*cycle_now - gtod->clock.cycle_last) & gtod->clock.mask;
        return v * gtod->clock.mult;
}

static int do_monotonic_boot(s64 *t, cycle_t *cycle_now)
{
        struct pvclock_gtod_data *gtod = &pvclock_gtod_data;
        unsigned long seq;
        int mode;
        u64 ns;

        do {
                seq = read_seqcount_begin(&gtod->seq);
                mode = gtod->clock.vclock_mode;
                ns = gtod->nsec_base;
                ns += vgettsc(cycle_now);
                ns >>= gtod->clock.shift;
                ns += gtod->boot_ns;
        } while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
        *t = ns;

        return mode;
}

/* returns true if host is using tsc clocksource */
static bool kvm_get_time_and_clockread(s64 *kernel_ns, cycle_t *cycle_now)
{
        /* checked again under seqlock below */
        if (pvclock_gtod_data.clock.vclock_mode != VCLOCK_TSC)
                return false;

        return do_monotonic_boot(kernel_ns, cycle_now) == VCLOCK_TSC;
}
#endif

/*
 *
 * Assuming a stable TSC across physical CPUS, and a stable TSC
 * across virtual CPUs, the following condition is possible.
 * Each numbered line represents an event visible to both
 * CPUs at the next numbered event.
 *
 * "timespecX" represents host monotonic time. "tscX" represents
 * RDTSC value.
 *
 *              VCPU0 on CPU0           |       VCPU1 on CPU1
 *
 * 1.  read timespec0,tsc0
 * 2.                                   | timespec1 = timespec0 + N
 *                                      | tsc1 = tsc0 + M
 * 3. transition to guest               | transition to guest
 * 4. ret0 = timespec0 + (rdtsc - tsc0) |
 * 5.                                   | ret1 = timespec1 + (rdtsc - tsc1)
 *                                      | ret1 = timespec0 + N + (rdtsc - (tsc0 + M))
 *
 * Since ret0 update is visible to VCPU1 at time 5, to obey monotonicity:
 *
 *      - ret0 < ret1
 *      - timespec0 + (rdtsc - tsc0) < timespec0 + N + (rdtsc - (tsc0 + M))
 *              ...
 *      - 0 < N - M => M < N
 *
 * That is, when timespec0 != timespec1, M < N. Unfortunately that is not
 * always the case (the difference between two distinct xtime instances
 * might be smaller then the difference between corresponding TSC reads,
 * when updating guest vcpus pvclock areas).
 *
 * To avoid that problem, do not allow visibility of distinct
 * system_timestamp/tsc_timestamp values simultaneously: use a master
 * copy of host monotonic time values. Update that master copy
 * in lockstep.
 *
 * Rely on synchronization of host TSCs and guest TSCs for monotonicity.
 *
 */

static void pvclock_update_vm_gtod_copy(struct kvm *kvm)
{
#ifdef CONFIG_X86_64
        struct kvm_arch *ka = &kvm->arch;
        int vclock_mode;
        bool host_tsc_clocksource, vcpus_matched;

        vcpus_matched = (ka->nr_vcpus_matched_tsc + 1 ==
                        atomic_read(&kvm->online_vcpus));

        /*
         * If the host uses TSC clock, then passthrough TSC as stable
         * to the guest.
         */
        host_tsc_clocksource = kvm_get_time_and_clockread(
                                        &ka->master_kernel_ns,
                                        &ka->master_cycle_now);

        ka->use_master_clock = host_tsc_clocksource && vcpus_matched
                                && !backwards_tsc_observed
                                && !ka->boot_vcpu_runs_old_kvmclock;

        if (ka->use_master_clock)
                atomic_set(&kvm_guest_has_master_clock, 1);

        vclock_mode = pvclock_gtod_data.clock.vclock_mode;
        trace_kvm_update_master_clock(ka->use_master_clock, vclock_mode,
                                        vcpus_matched);
#endif
}

static void kvm_gen_update_masterclock(struct kvm *kvm)
{
#ifdef CONFIG_X86_64
        int i;
        struct kvm_vcpu *vcpu;
        struct kvm_arch *ka = &kvm->arch;

        spin_lock(&ka->pvclock_gtod_sync_lock);
        kvm_make_mclock_inprogress_request(kvm);
        /* no guest entries from this point */
        pvclock_update_vm_gtod_copy(kvm);

        kvm_for_each_vcpu(i, vcpu, kvm)
                kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);

        /* guest entries allowed */
        kvm_for_each_vcpu(i, vcpu, kvm)
                clear_bit(KVM_REQ_MCLOCK_INPROGRESS, &vcpu->requests);

        spin_unlock(&ka->pvclock_gtod_sync_lock);
#endif
}

static int kvm_guest_time_update(struct kvm_vcpu *v)
{
        unsigned long flags, this_tsc_khz;
        struct kvm_vcpu_arch *vcpu = &v->arch;
        struct kvm_arch *ka = &v->kvm->arch;
        s64 kernel_ns;
        u64 tsc_timestamp, host_tsc;
        struct pvclock_vcpu_time_info guest_hv_clock;
        u8 pvclock_flags;
        bool use_master_clock;

        kernel_ns = 0;
        host_tsc = 0;

        /*
         * If the host uses TSC clock, then passthrough TSC as stable
         * to the guest.
         */
        spin_lock(&ka->pvclock_gtod_sync_lock);
        use_master_clock = ka->use_master_clock;
        if (use_master_clock) {
                host_tsc = ka->master_cycle_now;
                kernel_ns = ka->master_kernel_ns;
        }
        spin_unlock(&ka->pvclock_gtod_sync_lock);

        /* Keep irq disabled to prevent changes to the clock */
        local_irq_save(flags);
        this_tsc_khz = __this_cpu_read(cpu_tsc_khz);
        if (unlikely(this_tsc_khz == 0)) {
                local_irq_restore(flags);
                kvm_make_request(KVM_REQ_CLOCK_UPDATE, v);
                return 1;
        }
        if (!use_master_clock) {
                host_tsc = native_read_tsc();
                kernel_ns = get_kernel_ns();
        }

        tsc_timestamp = kvm_x86_ops->read_l1_tsc(v, host_tsc);

        /*
         * We may have to catch up the TSC to match elapsed wall clock
         * time for two reasons, even if kvmclock is used.
         *   1) CPU could have been running below the maximum TSC rate
         *   2) Broken TSC compensation resets the base at each VCPU
         *      entry to avoid unknown leaps of TSC even when running
         *      again on the same CPU.  This may cause apparent elapsed
         *      time to disappear, and the guest to stand still or run
         *      very slowly.
         */
        if (vcpu->tsc_catchup) {
                u64 tsc = compute_guest_tsc(v, kernel_ns);
                if (tsc > tsc_timestamp) {
                        adjust_tsc_offset_guest(v, tsc - tsc_timestamp);
                        tsc_timestamp = tsc;
                }
        }

        local_irq_restore(flags);

        if (!vcpu->pv_time_enabled)
                return 0;

        if (unlikely(vcpu->hw_tsc_khz != this_tsc_khz)) {
                kvm_get_time_scale(NSEC_PER_SEC / 1000, this_tsc_khz,
                                   &vcpu->hv_clock.tsc_shift,
                                   &vcpu->hv_clock.tsc_to_system_mul);
                vcpu->hw_tsc_khz = this_tsc_khz;
        }

        /* With all the info we got, fill in the values */
        vcpu->hv_clock.tsc_timestamp = tsc_timestamp;
        vcpu->hv_clock.system_time = kernel_ns + v->kvm->arch.kvmclock_offset;
        vcpu->last_guest_tsc = tsc_timestamp;

        if (unlikely(kvm_read_guest_cached(v->kvm, &vcpu->pv_time,
                &guest_hv_clock, sizeof(guest_hv_clock))))
                return 0;

        /* This VCPU is paused, but it's legal for a guest to read another
         * VCPU's kvmclock, so we really have to follow the specification where
         * it says that version is odd if data is being modified, and even after
         * it is consistent.
         *
         * Version field updates must be kept separate.  This is because
         * kvm_write_guest_cached might use a "rep movs" instruction, and
         * writes within a string instruction are weakly ordered.  So there
         * are three writes overall.
         *
         * As a small optimization, only write the version field in the first
         * and third write.  The vcpu->pv_time cache is still valid, because the
         * version field is the first in the struct.
         */
        BUILD_BUG_ON(offsetof(struct pvclock_vcpu_time_info, version) != 0);

        vcpu->hv_clock.version = guest_hv_clock.version + 1;
        kvm_write_guest_cached(v->kvm, &vcpu->pv_time,
                                &vcpu->hv_clock,
                                sizeof(vcpu->hv_clock.version));

        smp_wmb();

        /* retain PVCLOCK_GUEST_STOPPED if set in guest copy */
        pvclock_flags = (guest_hv_clock.flags & PVCLOCK_GUEST_STOPPED);

        if (vcpu->pvclock_set_guest_stopped_request) {
                pvclock_flags |= PVCLOCK_GUEST_STOPPED;
                vcpu->pvclock_set_guest_stopped_request = false;
        }

        pvclock_flags |= PVCLOCK_COUNTS_FROM_ZERO;

        /* If the host uses TSC clocksource, then it is stable */
        if (use_master_clock)
                pvclock_flags |= PVCLOCK_TSC_STABLE_BIT;

        vcpu->hv_clock.flags = pvclock_flags;

        trace_kvm_pvclock_update(v->vcpu_id, &vcpu->hv_clock);

        kvm_write_guest_cached(v->kvm, &vcpu->pv_time,
                                &vcpu->hv_clock,
                                sizeof(vcpu->hv_clock));

        smp_wmb();

        vcpu->hv_clock.version++;
        kvm_write_guest_cached(v->kvm, &vcpu->pv_time,
                                &vcpu->hv_clock,
                                sizeof(vcpu->hv_clock.version));
        return 0;
}

/*
 * kvmclock updates which are isolated to a given vcpu, such as
 * vcpu->cpu migration, should not allow system_timestamp from
 * the rest of the vcpus to remain static. Otherwise ntp frequency
 * correction applies to one vcpu's system_timestamp but not
 * the others.
 *
 * So in those cases, request a kvmclock update for all vcpus.
 * We need to rate-limit these requests though, as they can
 * considerably slow guests that have a large number of vcpus.
 * The time for a remote vcpu to update its kvmclock is bound
 * by the delay we use to rate-limit the updates.
 */

#define KVMCLOCK_UPDATE_DELAY msecs_to_jiffies(100)

static void kvmclock_update_fn(struct work_struct *work)
{
        int i;
        struct delayed_work *dwork = to_delayed_work(work);
        struct kvm_arch *ka = container_of(dwork, struct kvm_arch,
                                           kvmclock_update_work);
        struct kvm *kvm = container_of(ka, struct kvm, arch);
        struct kvm_vcpu *vcpu;

        kvm_for_each_vcpu(i, vcpu, kvm) {
                kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
                kvm_vcpu_kick(vcpu);
        }
}

static void kvm_gen_kvmclock_update(struct kvm_vcpu *v)
{
        struct kvm *kvm = v->kvm;

        kvm_make_request(KVM_REQ_CLOCK_UPDATE, v);
        schedule_delayed_work(&kvm->arch.kvmclock_update_work,
                                        KVMCLOCK_UPDATE_DELAY);
}

#define KVMCLOCK_SYNC_PERIOD (300 * HZ)

static void kvmclock_sync_fn(struct work_struct *work)
{
        struct delayed_work *dwork = to_delayed_work(work);
        struct kvm_arch *ka = container_of(dwork, struct kvm_arch,
                                           kvmclock_sync_work);
        struct kvm *kvm = container_of(ka, struct kvm, arch);

        if (!kvmclock_periodic_sync)
                return;

        schedule_delayed_work(&kvm->arch.kvmclock_update_work, 0);
        schedule_delayed_work(&kvm->arch.kvmclock_sync_work,
                                        KVMCLOCK_SYNC_PERIOD);
}

static int set_msr_mce(struct kvm_vcpu *vcpu, u32 msr, u64 data)
{
        u64 mcg_cap = vcpu->arch.mcg_cap;
        unsigned bank_num = mcg_cap & 0xff;

        switch (msr) {
        case MSR_IA32_MCG_STATUS:
                vcpu->arch.mcg_status = data;
                break;
        case MSR_IA32_MCG_CTL:
                if (!(mcg_cap & MCG_CTL_P))
                        return 1;
                if (data != 0 && data != ~(u64)0)
                        return -1;
                vcpu->arch.mcg_ctl = data;
                break;
        default:
                if (msr >= MSR_IA32_MC0_CTL &&
                    msr < MSR_IA32_MCx_CTL(bank_num)) {
                        u32 offset = msr - MSR_IA32_MC0_CTL;
                        /* only 0 or all 1s can be written to IA32_MCi_CTL
                         * some Linux kernels though clear bit 10 in bank 4 to
                         * workaround a BIOS/GART TBL issue on AMD K8s, ignore
                         * this to avoid an uncatched #GP in the guest
                         */
                        if ((offset & 0x3) == 0 &&
                            data != 0 && (data | (1 << 10)) != ~(u64)0)
                                return -1;
                        vcpu->arch.mce_banks[offset] = data;
                        break;
                }
                return 1;
        }
        return 0;
}

static int xen_hvm_config(struct kvm_vcpu *vcpu, u64 data)
{
        struct kvm *kvm = vcpu->kvm;
        int lm = is_long_mode(vcpu);
        u8 *blob_addr = lm ? (u8 *)(long)kvm->arch.xen_hvm_config.blob_addr_64
                : (u8 *)(long)kvm->arch.xen_hvm_config.blob_addr_32;
        u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64
                : kvm->arch.xen_hvm_config.blob_size_32;
        u32 page_num = data & ~PAGE_MASK;
        u64 page_addr = data & PAGE_MASK;
        u8 *page;
        int r;

        r = -E2BIG;
        if (page_num >= blob_size)
                goto out;
        r = -ENOMEM;
        page = memdup_user(blob_addr + (page_num * PAGE_SIZE), PAGE_SIZE);
        if (IS_ERR(page)) {
                r = PTR_ERR(page);
                goto out;
        }
        if (kvm_vcpu_write_guest(vcpu, page_addr, page, PAGE_SIZE))
                goto out_free;
        r = 0;
out_free:
        kfree(page);
out:
        return r;
}

static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data)
{
        gpa_t gpa = data & ~0x3f;

        /* Bits 2:5 are reserved, Should be zero */
        if (data & 0x3c)
                return 1;

        vcpu->arch.apf.msr_val = data;

        if (!(data & KVM_ASYNC_PF_ENABLED)) {
                kvm_clear_async_pf_completion_queue(vcpu);
                kvm_async_pf_hash_reset(vcpu);
                return 0;
        }

        if (kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.apf.data, gpa,
                                        sizeof(u32)))
                return 1;

        vcpu->arch.apf.send_user_only = !(data & KVM_ASYNC_PF_SEND_ALWAYS);
        kvm_async_pf_wakeup_all(vcpu);
        return 0;
}

static void kvmclock_reset(struct kvm_vcpu *vcpu)
{
        vcpu->arch.pv_time_enabled = false;
}

static void accumulate_steal_time(struct kvm_vcpu *vcpu)
{
        u64 delta;

        if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED))
                return;

        delta = current->sched_info.run_delay - vcpu->arch.st.last_steal;
        vcpu->arch.st.last_steal = current->sched_info.run_delay;
        vcpu->arch.st.accum_steal = delta;
}

static void record_steal_time(struct kvm_vcpu *vcpu)
{
        if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED))
                return;

        if (unlikely(kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.st.stime,
                &vcpu->arch.st.steal, sizeof(struct kvm_steal_time))))
                return;

        vcpu->arch.st.steal.steal += vcpu->arch.st.accum_steal;
        vcpu->arch.st.steal.version += 2;
        vcpu->arch.st.accum_steal = 0;

        kvm_write_guest_cached(vcpu->kvm, &vcpu->arch.st.stime,
                &vcpu->arch.st.steal, sizeof(struct kvm_steal_time));
}

int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
        bool pr = false;
        u32 msr = msr_info->index;
        u64 data = msr_info->data;

        switch (msr) {
        case MSR_AMD64_NB_CFG:
        case MSR_IA32_UCODE_REV:
        case MSR_IA32_UCODE_WRITE:
        case MSR_VM_HSAVE_PA:
        case MSR_AMD64_PATCH_LOADER:
        case MSR_AMD64_BU_CFG2:
                break;

        case MSR_EFER:
                return set_efer(vcpu, data);
        case MSR_K7_HWCR:
                data &= ~(u64)0x40;     /* ignore flush filter disable */
                data &= ~(u64)0x100;    /* ignore ignne emulation enable */
                data &= ~(u64)0x8;      /* ignore TLB cache disable */
                data &= ~(u64)0x40000;  /* ignore Mc status write enable */
                if (data != 0) {
                        vcpu_unimpl(vcpu, "unimplemented HWCR wrmsr: 0x%llx\n",
                                    data);
                        return 1;
                }
                break;
        case MSR_FAM10H_MMIO_CONF_BASE:
                if (data != 0) {
                        vcpu_unimpl(vcpu, "unimplemented MMIO_CONF_BASE wrmsr: "
                                    "0x%llx\n", data);
                        return 1;
                }
                break;
        case MSR_IA32_DEBUGCTLMSR:
                if (!data) {
                        /* We support the non-activated case already */
                        break;
                } else if (data & ~(DEBUGCTLMSR_LBR | DEBUGCTLMSR_BTF)) {
                        /* Values other than LBR and BTF are vendor-specific,
                           thus reserved and should throw a #GP */
                        return 1;
                }
                vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
                            __func__, data);
                break;
        case 0x200 ... 0x2ff:
                return kvm_mtrr_set_msr(vcpu, msr, data);
        case MSR_IA32_APICBASE:
                return kvm_set_apic_base(vcpu, msr_info);
        case APIC_BASE_MSR ... APIC_BASE_MSR + 0x3ff:
                return kvm_x2apic_msr_write(vcpu, msr, data);
        case MSR_IA32_TSCDEADLINE:
                kvm_set_lapic_tscdeadline_msr(vcpu, data);
                break;
        case MSR_IA32_TSC_ADJUST:
                if (guest_cpuid_has_tsc_adjust(vcpu)) {
                        if (!msr_info->host_initiated) {
                                s64 adj = data - vcpu->arch.ia32_tsc_adjust_msr;
                                kvm_x86_ops->adjust_tsc_offset(vcpu, adj, true);
                        }
                        vcpu->arch.ia32_tsc_adjust_msr = data;
                }
                break;
        case MSR_IA32_MISC_ENABLE:
                vcpu->arch.ia32_misc_enable_msr = data;
                break;
        case MSR_IA32_SMBASE:
                if (!msr_info->host_initiated)
                        return 1;
                vcpu->arch.smbase = data;
                break;
        case MSR_KVM_WALL_CLOCK_NEW:
        case MSR_KVM_WALL_CLOCK:
                vcpu->kvm->arch.wall_clock = data;
                kvm_write_wall_clock(vcpu->kvm, data);
                break;
        case MSR_KVM_SYSTEM_TIME_NEW:
        case MSR_KVM_SYSTEM_TIME: {
                u64 gpa_offset;
                struct kvm_arch *ka = &vcpu->kvm->arch;

                kvmclock_reset(vcpu);

                if (vcpu->vcpu_id == 0 && !msr_info->host_initiated) {
                        bool tmp = (msr == MSR_KVM_SYSTEM_TIME);

                        if (ka->boot_vcpu_runs_old_kvmclock != tmp)
                                set_bit(KVM_REQ_MASTERCLOCK_UPDATE,
                                        &vcpu->requests);

                        ka->boot_vcpu_runs_old_kvmclock = tmp;

                        ka->kvmclock_offset = -get_kernel_ns();
                }

                vcpu->arch.time = data;
                kvm_make_request(KVM_REQ_GLOBAL_CLOCK_UPDATE, vcpu);

                /* we verify if the enable bit is set... */
                if (!(data & 1))
                        break;

                gpa_offset = data & ~(PAGE_MASK | 1);

                if (kvm_gfn_to_hva_cache_init(vcpu->kvm,
                     &vcpu->arch.pv_time, data & ~1ULL,
                     sizeof(struct pvclock_vcpu_time_info)))
                        vcpu->arch.pv_time_enabled = false;
                else
                        vcpu->arch.pv_time_enabled = true;

                break;
        }
        case MSR_KVM_ASYNC_PF_EN:
                if (kvm_pv_enable_async_pf(vcpu, data))
                        return 1;
                break;
        case MSR_KVM_STEAL_TIME:

                if (unlikely(!sched_info_on()))
                        return 1;

                if (data & KVM_STEAL_RESERVED_MASK)
                        return 1;

                if (kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.st.stime,
                                                data & KVM_STEAL_VALID_BITS,
                                                sizeof(struct kvm_steal_time)))
                        return 1;

                vcpu->arch.st.msr_val = data;

                if (!(data & KVM_MSR_ENABLED))
                        break;

                vcpu->arch.st.last_steal = current->sched_info.run_delay;

                preempt_disable();
                accumulate_steal_time(vcpu);
                preempt_enable();

                kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu);

                break;
        case MSR_KVM_PV_EOI_EN:
                if (kvm_lapic_enable_pv_eoi(vcpu, data))
                        return 1;
                break;

        case MSR_IA32_MCG_CTL:
        case MSR_IA32_MCG_STATUS:
        case MSR_IA32_MC0_CTL ... MSR_IA32_MCx_CTL(KVM_MAX_MCE_BANKS) - 1:
                return set_msr_mce(vcpu, msr, data);

        case MSR_K7_PERFCTR0 ... MSR_K7_PERFCTR3:
        case MSR_P6_PERFCTR0 ... MSR_P6_PERFCTR1:
                pr = true; /* fall through */
        case MSR_K7_EVNTSEL0 ... MSR_K7_EVNTSEL3:
        case MSR_P6_EVNTSEL0 ... MSR_P6_EVNTSEL1:
                if (kvm_pmu_is_valid_msr(vcpu, msr))
                        return kvm_pmu_set_msr(vcpu, msr_info);

                if (pr || data != 0)
                        vcpu_unimpl(vcpu, "disabled perfctr wrmsr: "
                                    "0x%x data 0x%llx\n", msr, data);
                break;
        case MSR_K7_CLK_CTL:
                /*
                 * Ignore all writes to this no longer documented MSR.
                 * Writes are only relevant for old K7 processors,
                 * all pre-dating SVM, but a recommended workaround from
                 * AMD for these chips. It is possible to specify the
                 * affected processor models on the command line, hence
                 * the need to ignore the workaround.
                 */
                break;
        case HV_X64_MSR_GUEST_OS_ID ... HV_X64_MSR_SINT15:
                return kvm_hv_set_msr_common(vcpu, msr, data);
        case MSR_IA32_BBL_CR_CTL3:
                /* Drop writes to this legacy MSR -- see rdmsr
                 * counterpart for further detail.
                 */
                vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data %llx\n", msr, data);
                break;
        case MSR_AMD64_OSVW_ID_LENGTH:
                if (!guest_cpuid_has_osvw(vcpu))
                        return 1;
                vcpu->arch.osvw.length = data;
                break;
        case MSR_AMD64_OSVW_STATUS:
                if (!guest_cpuid_has_osvw(vcpu))
                        return 1;
                vcpu->arch.osvw.status = data;
                break;
        default:
                if (msr && (msr == vcpu->kvm->arch.xen_hvm_config.msr))
                        return xen_hvm_config(vcpu, data);
                if (kvm_pmu_is_valid_msr(vcpu, msr))
                        return kvm_pmu_set_msr(vcpu, msr_info);
                if (!ignore_msrs) {
                        vcpu_unimpl(vcpu, "unhandled wrmsr: 0x%x data %llx\n",
                                    msr, data);
                        return 1;
                } else {
                        vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data %llx\n",
                                    msr, data);
                        break;
                }
        }
        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_msr_common);


/*
 * Reads an msr value (of 'msr_index') into 'pdata'.
 * Returns 0 on success, non-0 otherwise.
 * Assumes vcpu_load() was already called.
 */
int kvm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
{
        return kvm_x86_ops->get_msr(vcpu, msr);
}
EXPORT_SYMBOL_GPL(kvm_get_msr);

static int get_msr_mce(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
{
        u64 data;
        u64 mcg_cap = vcpu->arch.mcg_cap;
        unsigned bank_num = mcg_cap & 0xff;

        switch (msr) {
        case MSR_IA32_P5_MC_ADDR:
        case MSR_IA32_P5_MC_TYPE:
                data = 0;
                break;
        case MSR_IA32_MCG_CAP:
                data = vcpu->arch.mcg_cap;
                break;
        case MSR_IA32_MCG_CTL:
                if (!(mcg_cap & MCG_CTL_P))
                        return 1;
                data = vcpu->arch.mcg_ctl;
                break;
        case MSR_IA32_MCG_STATUS:
                data = vcpu->arch.mcg_status;
                break;
        default:
                if (msr >= MSR_IA32_MC0_CTL &&
                    msr < MSR_IA32_MCx_CTL(bank_num)) {
                        u32 offset = msr - MSR_IA32_MC0_CTL;
                        data = vcpu->arch.mce_banks[offset];
                        break;
                }
                return 1;
        }
        *pdata = data;
        return 0;
}

int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
        switch (msr_info->index) {
        case MSR_IA32_PLATFORM_ID:
        case MSR_IA32_EBL_CR_POWERON:
        case MSR_IA32_DEBUGCTLMSR:
        case MSR_IA32_LASTBRANCHFROMIP:
        case MSR_IA32_LASTBRANCHTOIP:
        case MSR_IA32_LASTINTFROMIP:
        case MSR_IA32_LASTINTTOIP:
        case MSR_K8_SYSCFG:
        case MSR_K7_HWCR:
        case MSR_VM_HSAVE_PA:
        case MSR_K8_INT_PENDING_MSG:
        case MSR_AMD64_NB_CFG:
        case MSR_FAM10H_MMIO_CONF_BASE:
        case MSR_AMD64_BU_CFG2:
                msr_info->data = 0;
                break;
        case MSR_K7_EVNTSEL0 ... MSR_K7_EVNTSEL3:
        case MSR_K7_PERFCTR0 ... MSR_K7_PERFCTR3:
        case MSR_P6_PERFCTR0 ... MSR_P6_PERFCTR1:
        case MSR_P6_EVNTSEL0 ... MSR_P6_EVNTSEL1:
                if (kvm_pmu_is_valid_msr(vcpu, msr_info->index))
                        return kvm_pmu_get_msr(vcpu, msr_info->index, &msr_info->data);
                msr_info->data = 0;
                break;
        case MSR_IA32_UCODE_REV:
                msr_info->data = 0x100000000ULL;
                break;
        case MSR_MTRRcap:
        case 0x200 ... 0x2ff:
                return kvm_mtrr_get_msr(vcpu, msr_info->index, &msr_info->data);
        case 0xcd: /* fsb frequency */
                msr_info->data = 3;
                break;
                /*
                 * MSR_EBC_FREQUENCY_ID
                 * Conservative value valid for even the basic CPU models.
                 * Models 0,1: 000 in bits 23:21 indicating a bus speed of
                 * 100MHz, model 2 000 in bits 18:16 indicating 100MHz,
                 * and 266MHz for model 3, or 4. Set Core Clock
                 * Frequency to System Bus Frequency Ratio to 1 (bits
                 * 31:24) even though these are only valid for CPU
                 * models > 2, however guests may end up dividing or
                 * multiplying by zero otherwise.
                 */
        case MSR_EBC_FREQUENCY_ID:
                msr_info->data = 1 << 24;
                break;
        case MSR_IA32_APICBASE:
                msr_info->data = kvm_get_apic_base(vcpu);
                break;
        case APIC_BASE_MSR ... APIC_BASE_MSR + 0x3ff:
                return kvm_x2apic_msr_read(vcpu, msr_info->index, &msr_info->data);
                break;
        case MSR_IA32_TSCDEADLINE:
                msr_info->data = kvm_get_lapic_tscdeadline_msr(vcpu);
                break;
        case MSR_IA32_TSC_ADJUST:
                msr_info->data = (u64)vcpu->arch.ia32_tsc_adjust_msr;
                break;
        case MSR_IA32_MISC_ENABLE:
                msr_info->data = vcpu->arch.ia32_misc_enable_msr;
                break;
        case MSR_IA32_SMBASE:
                if (!msr_info->host_initiated)
                        return 1;
                msr_info->data = vcpu->arch.smbase;
                break;
        case MSR_IA32_PERF_STATUS:
                /* TSC increment by tick */
                msr_info->data = 1000ULL;
                /* CPU multiplier */
                msr_info->data |= (((uint64_t)4ULL) << 40);
                break;
        case MSR_EFER:
                msr_info->data = vcpu->arch.efer;
                break;
        case MSR_KVM_WALL_CLOCK:
        case MSR_KVM_WALL_CLOCK_NEW:
                msr_info->data = vcpu->kvm->arch.wall_clock;
                break;
        case MSR_KVM_SYSTEM_TIME:
        case MSR_KVM_SYSTEM_TIME_NEW:
                msr_info->data = vcpu->arch.time;
                break;
        case MSR_KVM_ASYNC_PF_EN:
                msr_info->data = vcpu->arch.apf.msr_val;
                break;
        case MSR_KVM_STEAL_TIME:
                msr_info->data = vcpu->arch.st.msr_val;
                break;
        case MSR_KVM_PV_EOI_EN:
                msr_info->data = vcpu->arch.pv_eoi.msr_val;
                break;
        case MSR_IA32_P5_MC_ADDR:
        case MSR_IA32_P5_MC_TYPE:
        case MSR_IA32_MCG_CAP:
        case MSR_IA32_MCG_CTL:
        case MSR_IA32_MCG_STATUS:
        case MSR_IA32_MC0_CTL ... MSR_IA32_MCx_CTL(KVM_MAX_MCE_BANKS) - 1:
                return get_msr_mce(vcpu, msr_info->index, &msr_info->data);
        case MSR_K7_CLK_CTL:
                /*
                 * Provide expected ramp-up count for K7. All other
                 * are set to zero, indicating minimum divisors for
                 * every field.
                 *
                 * This prevents guest kernels on AMD host with CPU
                 * type 6, model 8 and higher from exploding due to
                 * the rdmsr failing.
                 */
                msr_info->data = 0x20000000;
                break;
        case HV_X64_MSR_GUEST_OS_ID ... HV_X64_MSR_SINT15:
                return kvm_hv_get_msr_common(vcpu,
                                             msr_info->index, &msr_info->data);
                break;
        case MSR_IA32_BBL_CR_CTL3:
                /* This legacy MSR exists but isn't fully documented in current
                 * silicon.  It is however accessed by winxp in very narrow
                 * scenarios where it sets bit #19, itself documented as
                 * a "reserved" bit.  Best effort attempt to source coherent
                 * read data here should the balance of the register be
                 * interpreted by the guest:
                 *
                 * L2 cache control register 3: 64GB range, 256KB size,
                 * enabled, latency 0x1, configured
                 */
                msr_info->data = 0xbe702111;
                break;
        case MSR_AMD64_OSVW_ID_LENGTH:
                if (!guest_cpuid_has_osvw(vcpu))
                        return 1;
                msr_info->data = vcpu->arch.osvw.length;
                break;
        case MSR_AMD64_OSVW_STATUS:
                if (!guest_cpuid_has_osvw(vcpu))
                        return 1;
                msr_info->data = vcpu->arch.osvw.status;
                break;
        default:
                if (kvm_pmu_is_valid_msr(vcpu, msr_info->index))
                        return kvm_pmu_get_msr(vcpu, msr_info->index, &msr_info->data);
                if (!ignore_msrs) {
                        vcpu_unimpl(vcpu, "unhandled rdmsr: 0x%x\n", msr_info->index);
                        return 1;
                } else {
                        vcpu_unimpl(vcpu, "ignored rdmsr: 0x%x\n", msr_info->index);
                        msr_info->data = 0;
                }
                break;
        }
        return 0;
}
EXPORT_SYMBOL_GPL(kvm_get_msr_common);

/*
 * Read or write a bunch of msrs. All parameters are kernel addresses.
 *
 * @return number of msrs set successfully.
 */
static int __msr_io(struct kvm_vcpu *vcpu, struct kvm_msrs *msrs,
                    struct kvm_msr_entry *entries,
                    int (*do_msr)(struct kvm_vcpu *vcpu,
                                  unsigned index, u64 *data))
{
        int i, idx;

        idx = srcu_read_lock(&vcpu->kvm->srcu);
        for (i = 0; i < msrs->nmsrs; ++i)
                if (do_msr(vcpu, entries[i].index, &entries[i].data))
                        break;
        srcu_read_unlock(&vcpu->kvm->srcu, idx);

        return i;
}

/*
 * Read or write a bunch of msrs. Parameters are user addresses.
 *
 * @return number of msrs set successfully.
 */
static int msr_io(struct kvm_vcpu *vcpu, struct kvm_msrs __user *user_msrs,
                  int (*do_msr)(struct kvm_vcpu *vcpu,
                                unsigned index, u64 *data),
                  int writeback)
{
        struct kvm_msrs msrs;
        struct kvm_msr_entry *entries;
        int r, n;
        unsigned size;

        r = -EFAULT;
        if (copy_from_user(&msrs, user_msrs, sizeof msrs))
                goto out;

        r = -E2BIG;
        if (msrs.nmsrs >= MAX_IO_MSRS)
                goto out;

        size = sizeof(struct kvm_msr_entry) * msrs.nmsrs;
        entries = memdup_user(user_msrs->entries, size);
        if (IS_ERR(entries)) {
                r = PTR_ERR(entries);
                goto out;
        }

        r = n = __msr_io(vcpu, &msrs, entries, do_msr);
        if (r < 0)
                goto out_free;

        r = -EFAULT;
        if (writeback && copy_to_user(user_msrs->entries, entries, size))
                goto out_free;

        r = n;

out_free:
        kfree(entries);
out:
        return r;
}

int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
{
        int r;

        switch (ext) {
        case KVM_CAP_IRQCHIP:
        case KVM_CAP_HLT:
        case KVM_CAP_MMU_SHADOW_CACHE_CONTROL:
        case KVM_CAP_SET_TSS_ADDR:
        case KVM_CAP_EXT_CPUID:
        case KVM_CAP_EXT_EMUL_CPUID:
        case KVM_CAP_CLOCKSOURCE:
        case KVM_CAP_PIT:
        case KVM_CAP_NOP_IO_DELAY:
        case KVM_CAP_MP_STATE:
        case KVM_CAP_SYNC_MMU:
        case KVM_CAP_USER_NMI:
        case KVM_CAP_REINJECT_CONTROL:
        case KVM_CAP_IRQ_INJECT_STATUS:
        case KVM_CAP_IOEVENTFD:
        case KVM_CAP_IOEVENTFD_NO_LENGTH:
        case KVM_CAP_PIT2:
        case KVM_CAP_PIT_STATE2:
        case KVM_CAP_SET_IDENTITY_MAP_ADDR:
        case KVM_CAP_XEN_HVM:
        case KVM_CAP_ADJUST_CLOCK:
        case KVM_CAP_VCPU_EVENTS:
        case KVM_CAP_HYPERV:
        case KVM_CAP_HYPERV_VAPIC:
        case KVM_CAP_HYPERV_SPIN:
        case KVM_CAP_PCI_SEGMENT:
        case KVM_CAP_DEBUGREGS:
        case KVM_CAP_X86_ROBUST_SINGLESTEP:
        case KVM_CAP_XSAVE:
        case KVM_CAP_ASYNC_PF:
        case KVM_CAP_GET_TSC_KHZ:
        case KVM_CAP_KVMCLOCK_CTRL:
        case KVM_CAP_READONLY_MEM:
        case KVM_CAP_HYPERV_TIME:
        case KVM_CAP_IOAPIC_POLARITY_IGNORED:
        case KVM_CAP_TSC_DEADLINE_TIMER:
        case KVM_CAP_ENABLE_CAP_VM:
        case KVM_CAP_DISABLE_QUIRKS:
#ifdef CONFIG_KVM_DEVICE_ASSIGNMENT
        case KVM_CAP_ASSIGN_DEV_IRQ:
        case KVM_CAP_PCI_2_3:
#endif
                r = 1;
                break;
        case KVM_CAP_X86_SMM:
                /* SMBASE is usually relocated above 1M on modern chipsets,
                 * and SMM handlers might indeed rely on 4G segment limits,
                 * so do not report SMM to be available if real mode is
                 * emulated via vm86 mode.  Still, do not go to great lengths
                 * to avoid userspace's usage of the feature, because it is a
                 * fringe case that is not enabled except via specific settings
                 * of the module parameters.
                 */
                r = kvm_x86_ops->cpu_has_high_real_mode_segbase();
                break;
        case KVM_CAP_COALESCED_MMIO:
                r = KVM_COALESCED_MMIO_PAGE_OFFSET;
                break;
        case KVM_CAP_VAPIC:
                r = !kvm_x86_ops->cpu_has_accelerated_tpr();
                break;
        case KVM_CAP_NR_VCPUS:
                r = KVM_SOFT_MAX_VCPUS;
                break;
        case KVM_CAP_MAX_VCPUS:
                r = KVM_MAX_VCPUS;
                break;
        case KVM_CAP_NR_MEMSLOTS:
                r = KVM_USER_MEM_SLOTS;
                break;
        case KVM_CAP_PV_MMU:    /* obsolete */
                r = 0;
                break;
#ifdef CONFIG_KVM_DEVICE_ASSIGNMENT
        case KVM_CAP_IOMMU:
                r = iommu_present(&pci_bus_type);
                break;
#endif
        case KVM_CAP_MCE:
                r = KVM_MAX_MCE_BANKS;
                break;
        case KVM_CAP_XCRS:
                r = cpu_has_xsave;
                break;
        case KVM_CAP_TSC_CONTROL:
                r = kvm_has_tsc_control;
                break;
        default:
                r = 0;
                break;
        }
        return r;

}

long kvm_arch_dev_ioctl(struct file *filp,
                        unsigned int ioctl, unsigned long arg)
{
        void __user *argp = (void __user *)arg;
        long r;

        switch (ioctl) {
        case KVM_GET_MSR_INDEX_LIST: {
                struct kvm_msr_list __user *user_msr_list = argp;
                struct kvm_msr_list msr_list;
                unsigned n;

                r = -EFAULT;
                if (copy_from_user(&msr_list, user_msr_list, sizeof msr_list))
                        goto out;
                n = msr_list.nmsrs;
                msr_list.nmsrs = num_msrs_to_save + num_emulated_msrs;
                if (copy_to_user(user_msr_list, &msr_list, sizeof msr_list))
                        goto out;
                r = -E2BIG;
                if (n < msr_list.nmsrs)
                        goto out;
                r = -EFAULT;
                if (copy_to_user(user_msr_list->indices, &msrs_to_save,
                                 num_msrs_to_save * sizeof(u32)))
                        goto out;
                if (copy_to_user(user_msr_list->indices + num_msrs_to_save,
                                 &emulated_msrs,
                                 num_emulated_msrs * sizeof(u32)))
                        goto out;
                r = 0;
                break;
        }
        case KVM_GET_SUPPORTED_CPUID:
        case KVM_GET_EMULATED_CPUID: {
                struct kvm_cpuid2 __user *cpuid_arg = argp;
                struct kvm_cpuid2 cpuid;

                r = -EFAULT;
                if (copy_from_user(&cpuid, cpuid_arg, sizeof cpuid))
                        goto out;

                r = kvm_dev_ioctl_get_cpuid(&cpuid, cpuid_arg->entries,
                                            ioctl);
                if (r)
                        goto out;

                r = -EFAULT;
                if (copy_to_user(cpuid_arg, &cpuid, sizeof cpuid))
                        goto out;
                r = 0;
                break;
        }
        case KVM_X86_GET_MCE_CAP_SUPPORTED: {
                u64 mce_cap;

                mce_cap = KVM_MCE_CAP_SUPPORTED;
                r = -EFAULT;
                if (copy_to_user(argp, &mce_cap, sizeof mce_cap))
                        goto out;
                r = 0;
                break;
        }
        default:
                r = -EINVAL;
        }
out:
        return r;
}

static void wbinvd_ipi(void *garbage)
{
        wbinvd();
}

static bool need_emulate_wbinvd(struct kvm_vcpu *vcpu)
{
        return kvm_arch_has_noncoherent_dma(vcpu->kvm);
}

void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
        /* Address WBINVD may be executed by guest */
        if (need_emulate_wbinvd(vcpu)) {
                if (kvm_x86_ops->has_wbinvd_exit())
                        cpumask_set_cpu(cpu, vcpu->arch.wbinvd_dirty_mask);
                else if (vcpu->cpu != -1 && vcpu->cpu != cpu)
                        smp_call_function_single(vcpu->cpu,
                                        wbinvd_ipi, NULL, 1);
        }

        kvm_x86_ops->vcpu_load(vcpu, cpu);

        /* Apply any externally detected TSC adjustments (due to suspend) */
        if (unlikely(vcpu->arch.tsc_offset_adjustment)) {
                adjust_tsc_offset_host(vcpu, vcpu->arch.tsc_offset_adjustment);
                vcpu->arch.tsc_offset_adjustment = 0;
                kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
        }

        if (unlikely(vcpu->cpu != cpu) || check_tsc_unstable()) {
                s64 tsc_delta = !vcpu->arch.last_host_tsc ? 0 :
                                native_read_tsc() - vcpu->arch.last_host_tsc;
                if (tsc_delta < 0)
                        mark_tsc_unstable("KVM discovered backwards TSC");
                if (check_tsc_unstable()) {
                        u64 offset = kvm_x86_ops->compute_tsc_offset(vcpu,
                                                vcpu->arch.last_guest_tsc);
                        kvm_x86_ops->write_tsc_offset(vcpu, offset);
                        vcpu->arch.tsc_catchup = 1;
                }
                /*
                 * On a host with synchronized TSC, there is no need to update
                 * kvmclock on vcpu->cpu migration
                 */
                if (!vcpu->kvm->arch.use_master_clock || vcpu->cpu == -1)
                        kvm_make_request(KVM_REQ_GLOBAL_CLOCK_UPDATE, vcpu);
                if (vcpu->cpu != cpu)
                        kvm_migrate_timers(vcpu);
                vcpu->cpu = cpu;
        }

        accumulate_steal_time(vcpu);
        kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu);
}

void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
{
        kvm_x86_ops->vcpu_put(vcpu);
        kvm_put_guest_fpu(vcpu);
        vcpu->arch.last_host_tsc = native_read_tsc();
}

static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,
                                    struct kvm_lapic_state *s)
{
        kvm_x86_ops->sync_pir_to_irr(vcpu);
        memcpy(s->regs, vcpu->arch.apic->regs, sizeof *s);

        return 0;
}

static int kvm_vcpu_ioctl_set_lapic(struct kvm_vcpu *vcpu,
                                    struct kvm_lapic_state *s)
{
        kvm_apic_post_state_restore(vcpu, s);
        update_cr8_intercept(vcpu);

        return 0;
}

static int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu,
                                    struct kvm_interrupt *irq)
{
        if (irq->irq >= KVM_NR_INTERRUPTS)
                return -EINVAL;
        if (irqchip_in_kernel(vcpu->kvm))
                return -ENXIO;

        kvm_queue_interrupt(vcpu, irq->irq, false);
        kvm_make_request(KVM_REQ_EVENT, vcpu);

        return 0;
}

static int kvm_vcpu_ioctl_nmi(struct kvm_vcpu *vcpu)
{
        kvm_inject_nmi(vcpu);

        return 0;
}

static int kvm_vcpu_ioctl_smi(struct kvm_vcpu *vcpu)
{
        kvm_make_request(KVM_REQ_SMI, vcpu);

        return 0;
}

static int vcpu_ioctl_tpr_access_reporting(struct kvm_vcpu *vcpu,
                                           struct kvm_tpr_access_ctl *tac)
{
        if (tac->flags)
                return -EINVAL;
        vcpu->arch.tpr_access_reporting = !!tac->enabled;
        return 0;
}

static int kvm_vcpu_ioctl_x86_setup_mce(struct kvm_vcpu *vcpu,
                                        u64 mcg_cap)
{
        int r;
        unsigned bank_num = mcg_cap & 0xff, bank;

        r = -EINVAL;
        if (!bank_num || bank_num >= KVM_MAX_MCE_BANKS)
                goto out;
        if (mcg_cap & ~(KVM_MCE_CAP_SUPPORTED | 0xff | 0xff0000))
                goto out;
        r = 0;
        vcpu->arch.mcg_cap = mcg_cap;
        /* Init IA32_MCG_CTL to all 1s */
        if (mcg_cap & MCG_CTL_P)
                vcpu->arch.mcg_ctl = ~(u64)0;
        /* Init IA32_MCi_CTL to all 1s */
        for (bank = 0; bank < bank_num; bank++)
                vcpu->arch.mce_banks[bank*4] = ~(u64)0;
out:
        return r;
}

static int kvm_vcpu_ioctl_x86_set_mce(struct kvm_vcpu *vcpu,
                                      struct kvm_x86_mce *mce)
{
        u64 mcg_cap = vcpu->arch.mcg_cap;
        unsigned bank_num = mcg_cap & 0xff;
        u64 *banks = vcpu->arch.mce_banks;

        if (mce->bank >= bank_num || !(mce->status & MCI_STATUS_VAL))
                return -EINVAL;
        /*
         * if IA32_MCG_CTL is not all 1s, the uncorrected error
         * reporting is disabled
         */
        if ((mce->status & MCI_STATUS_UC) && (mcg_cap & MCG_CTL_P) &&
            vcpu->arch.mcg_ctl != ~(u64)0)
                return 0;
        banks += 4 * mce->bank;
        /*
         * if IA32_MCi_CTL is not all 1s, the uncorrected error
         * reporting is disabled for the bank
         */
        if ((mce->status & MCI_STATUS_UC) && banks[0] != ~(u64)0)
                return 0;
        if (mce->status & MCI_STATUS_UC) {
                if ((vcpu->arch.mcg_status & MCG_STATUS_MCIP) ||
                    !kvm_read_cr4_bits(vcpu, X86_CR4_MCE)) {
                        kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
                        return 0;
                }
                if (banks[1] & MCI_STATUS_VAL)
                        mce->status |= MCI_STATUS_OVER;
                banks[2] = mce->addr;
                banks[3] = mce->misc;
                vcpu->arch.mcg_status = mce->mcg_status;
                banks[1] = mce->status;
                kvm_queue_exception(vcpu, MC_VECTOR);
        } else if (!(banks[1] & MCI_STATUS_VAL)
                   || !(banks[1] & MCI_STATUS_UC)) {
                if (banks[1] & MCI_STATUS_VAL)
                        mce->status |= MCI_STATUS_OVER;
                banks[2] = mce->addr;
                banks[3] = mce->misc;
                banks[1] = mce->status;
        } else
                banks[1] |= MCI_STATUS_OVER;
        return 0;
}

static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu,
                                               struct kvm_vcpu_events *events)
{
        process_nmi(vcpu);
        events->exception.injected =
                vcpu->arch.exception.pending &&
                !kvm_exception_is_soft(vcpu->arch.exception.nr);
        events->exception.nr = vcpu->arch.exception.nr;
        events->exception.has_error_code = vcpu->arch.exception.has_error_code;
        events->exception.pad = 0;
        events->exception.error_code = vcpu->arch.exception.error_code;

        events->interrupt.injected =
                vcpu->arch.interrupt.pending && !vcpu->arch.interrupt.soft;
        events->interrupt.nr = vcpu->arch.interrupt.nr;
        events->interrupt.soft = 0;
        events->interrupt.shadow = kvm_x86_ops->get_interrupt_shadow(vcpu);

        events->nmi.injected = vcpu->arch.nmi_injected;
        events->nmi.pending = vcpu->arch.nmi_pending != 0;
        events->nmi.masked = kvm_x86_ops->get_nmi_mask(vcpu);
        events->nmi.pad = 0;

        events->sipi_vector = 0; /* never valid when reporting to user space */

        events->smi.smm = is_smm(vcpu);
        events->smi.pending = vcpu->arch.smi_pending;
        events->smi.smm_inside_nmi =
                !!(vcpu->arch.hflags & HF_SMM_INSIDE_NMI_MASK);
        events->smi.latched_init = kvm_lapic_latched_init(vcpu);

        events->flags = (KVM_VCPUEVENT_VALID_NMI_PENDING
                         | KVM_VCPUEVENT_VALID_SHADOW
                         | KVM_VCPUEVENT_VALID_SMM);
        memset(&events->reserved, 0, sizeof(events->reserved));
}

static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
                                              struct kvm_vcpu_events *events)
{
        if (events->flags & ~(KVM_VCPUEVENT_VALID_NMI_PENDING
                              | KVM_VCPUEVENT_VALID_SIPI_VECTOR
                              | KVM_VCPUEVENT_VALID_SHADOW
                              | KVM_VCPUEVENT_VALID_SMM))
                return -EINVAL;

        process_nmi(vcpu);
        vcpu->arch.exception.pending = events->exception.injected;
        vcpu->arch.exception.nr = events->exception.nr;
        vcpu->arch.exception.has_error_code = events->exception.has_error_code;
        vcpu->arch.exception.error_code = events->exception.error_code;

        vcpu->arch.interrupt.pending = events->interrupt.injected;
        vcpu->arch.interrupt.nr = events->interrupt.nr;
        vcpu->arch.interrupt.soft = events->interrupt.soft;
        if (events->flags & KVM_VCPUEVENT_VALID_SHADOW)
                kvm_x86_ops->set_interrupt_shadow(vcpu,
                                                  events->interrupt.shadow);

        vcpu->arch.nmi_injected = events->nmi.injected;
        if (events->flags & KVM_VCPUEVENT_VALID_NMI_PENDING)
                vcpu->arch.nmi_pending = events->nmi.pending;
        kvm_x86_ops->set_nmi_mask(vcpu, events->nmi.masked);

        if (events->flags & KVM_VCPUEVENT_VALID_SIPI_VECTOR &&
            kvm_vcpu_has_lapic(vcpu))
                vcpu->arch.apic->sipi_vector = events->sipi_vector;

        if (events->flags & KVM_VCPUEVENT_VALID_SMM) {
                if (events->smi.smm)
                        vcpu->arch.hflags |= HF_SMM_MASK;
                else
                        vcpu->arch.hflags &= ~HF_SMM_MASK;
                vcpu->arch.smi_pending = events->smi.pending;
                if (events->smi.smm_inside_nmi)
                        vcpu->arch.hflags |= HF_SMM_INSIDE_NMI_MASK;
                else
                        vcpu->arch.hflags &= ~HF_SMM_INSIDE_NMI_MASK;
                if (kvm_vcpu_has_lapic(vcpu)) {
                        if (events->smi.latched_init)
                                set_bit(KVM_APIC_INIT, &vcpu->arch.apic->pending_events);
                        else
                                clear_bit(KVM_APIC_INIT, &vcpu->arch.apic->pending_events);
                }
        }

        kvm_make_request(KVM_REQ_EVENT, vcpu);

        return 0;
}

static void kvm_vcpu_ioctl_x86_get_debugregs(struct kvm_vcpu *vcpu,
                                             struct kvm_debugregs *dbgregs)
{
        unsigned long val;

        memcpy(dbgregs->db, vcpu->arch.db, sizeof(vcpu->arch.db));
        kvm_get_dr(vcpu, 6, &val);
        dbgregs->dr6 = val;
        dbgregs->dr7 = vcpu->arch.dr7;
        dbgregs->flags = 0;
        memset(&dbgregs->reserved, 0, sizeof(dbgregs->reserved));
}

static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu,
                                            struct kvm_debugregs *dbgregs)
{
        if (dbgregs->flags)
                return -EINVAL;

        memcpy(vcpu->arch.db, dbgregs->db, sizeof(vcpu->arch.db));
        kvm_update_dr0123(vcpu);
        vcpu->arch.dr6 = dbgregs->dr6;
        kvm_update_dr6(vcpu);
        vcpu->arch.dr7 = dbgregs->dr7;
        kvm_update_dr7(vcpu);

        return 0;
}

#define XSTATE_COMPACTION_ENABLED (1ULL << 63)

static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu)
{
        struct xregs_state *xsave = &vcpu->arch.guest_fpu.state.xsave;
        u64 xstate_bv = xsave->header.xfeatures;
        u64 valid;

        /*
         * Copy legacy XSAVE area, to avoid complications with CPUID
         * leaves 0 and 1 in the loop below.
         */
        memcpy(dest, xsave, XSAVE_HDR_OFFSET);

        /* Set XSTATE_BV */
        *(u64 *)(dest + XSAVE_HDR_OFFSET) = xstate_bv;

        /*
         * Copy each region from the possibly compacted offset to the
         * non-compacted offset.
         */
        valid = xstate_bv & ~XSTATE_FPSSE;
        while (valid) {
                u64 feature = valid & -valid;
                int index = fls64(feature) - 1;
                void *src = get_xsave_addr(xsave, feature);

                if (src) {
                        u32 size, offset, ecx, edx;
                        cpuid_count(XSTATE_CPUID, index,
                                    &size, &offset, &ecx, &edx);
                        memcpy(dest + offset, src, size);
                }

                valid -= feature;
        }
}

static void load_xsave(struct kvm_vcpu *vcpu, u8 *src)
{
        struct xregs_state *xsave = &vcpu->arch.guest_fpu.state.xsave;
        u64 xstate_bv = *(u64 *)(src + XSAVE_HDR_OFFSET);
        u64 valid;

        /*
         * Copy legacy XSAVE area, to avoid complications with CPUID
         * leaves 0 and 1 in the loop below.
         */
        memcpy(xsave, src, XSAVE_HDR_OFFSET);

        /* Set XSTATE_BV and possibly XCOMP_BV.  */
        xsave->header.xfeatures = xstate_bv;
        if (cpu_has_xsaves)
                xsave->header.xcomp_bv = host_xcr0 | XSTATE_COMPACTION_ENABLED;

        /*
         * Copy each region from the non-compacted offset to the
         * possibly compacted offset.
         */
        valid = xstate_bv & ~XSTATE_FPSSE;
        while (valid) {
                u64 feature = valid & -valid;
                int index = fls64(feature) - 1;
                void *dest = get_xsave_addr(xsave, feature);

                if (dest) {
                        u32 size, offset, ecx, edx;
                        cpuid_count(XSTATE_CPUID, index,
                                    &size, &offset, &ecx, &edx);
                        memcpy(dest, src + offset, size);
                }

                valid -= feature;
        }
}

static void kvm_vcpu_ioctl_x86_get_xsave(struct kvm_vcpu *vcpu,
                                         struct kvm_xsave *guest_xsave)
{
        if (cpu_has_xsave) {
                memset(guest_xsave, 0, sizeof(struct kvm_xsave));
                fill_xsave((u8 *) guest_xsave->region, vcpu);
        } else {
                memcpy(guest_xsave->region,
                        &vcpu->arch.guest_fpu.state.fxsave,
                        sizeof(struct fxregs_state));
                *(u64 *)&guest_xsave->region[XSAVE_HDR_OFFSET / sizeof(u32)] =
                        XSTATE_FPSSE;
        }
}

static int kvm_vcpu_ioctl_x86_set_xsave(struct kvm_vcpu *vcpu,
                                        struct kvm_xsave *guest_xsave)
{
        u64 xstate_bv =
                *(u64 *)&guest_xsave->region[XSAVE_HDR_OFFSET / sizeof(u32)];

        if (cpu_has_xsave) {
                /*
                 * Here we allow setting states that are not present in
                 * CPUID leaf 0xD, index 0, EDX:EAX.  This is for compatibility
                 * with old userspace.
                 */
                if (xstate_bv & ~kvm_supported_xcr0())
                        return -EINVAL;
                load_xsave(vcpu, (u8 *)guest_xsave->region);
        } else {
                if (xstate_bv & ~XSTATE_FPSSE)
                        return -EINVAL;
                memcpy(&vcpu->arch.guest_fpu.state.fxsave,
                        guest_xsave->region, sizeof(struct fxregs_state));
        }
        return 0;
}

static void kvm_vcpu_ioctl_x86_get_xcrs(struct kvm_vcpu *vcpu,
                                        struct kvm_xcrs *guest_xcrs)
{
        if (!cpu_has_xsave) {
                guest_xcrs->nr_xcrs = 0;
                return;
        }

        guest_xcrs->nr_xcrs = 1;
        guest_xcrs->flags = 0;
        guest_xcrs->xcrs[0].xcr = XCR_XFEATURE_ENABLED_MASK;
        guest_xcrs->xcrs[0].value = vcpu->arch.xcr0;
}

static int kvm_vcpu_ioctl_x86_set_xcrs(struct kvm_vcpu *vcpu,
                                       struct kvm_xcrs *guest_xcrs)
{
        int i, r = 0;

        if (!cpu_has_xsave)
                return -EINVAL;

        if (guest_xcrs->nr_xcrs > KVM_MAX_XCRS || guest_xcrs->flags)
                return -EINVAL;

        for (i = 0; i < guest_xcrs->nr_xcrs; i++)
                /* Only support XCR0 currently */
                if (guest_xcrs->xcrs[i].xcr == XCR_XFEATURE_ENABLED_MASK) {
                        r = __kvm_set_xcr(vcpu, XCR_XFEATURE_ENABLED_MASK,
                                guest_xcrs->xcrs[i].value);
                        break;
                }
        if (r)
                r = -EINVAL;
        return r;
}

/*
 * kvm_set_guest_paused() indicates to the guest kernel that it has been
 * stopped by the hypervisor.  This function will be called from the host only.
 * EINVAL is returned when the host attempts to set the flag for a guest that
 * does not support pv clocks.
 */
static int kvm_set_guest_paused(struct kvm_vcpu *vcpu)
{
        if (!vcpu->arch.pv_time_enabled)
                return -EINVAL;
        vcpu->arch.pvclock_set_guest_stopped_request = true;
        kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
        return 0;
}

long kvm_arch_vcpu_ioctl(struct file *filp,
                         unsigned int ioctl, unsigned long arg)
{
        struct kvm_vcpu *vcpu = filp->private_data;
        void __user *argp = (void __user *)arg;
        int r;
        union {
                struct kvm_lapic_state *lapic;
                struct kvm_xsave *xsave;
                struct kvm_xcrs *xcrs;
                void *buffer;
        } u;

        u.buffer = NULL;
        switch (ioctl) {
        case KVM_GET_LAPIC: {
                r = -EINVAL;
                if (!vcpu->arch.apic)
                        goto out;
                u.lapic = kzalloc(sizeof(struct kvm_lapic_state), GFP_KERNEL);

                r = -ENOMEM;
                if (!u.lapic)
                        goto out;
                r = kvm_vcpu_ioctl_get_lapic(vcpu, u.lapic);
                if (r)
                        goto out;
                r = -EFAULT;
                if (copy_to_user(argp, u.lapic, sizeof(struct kvm_lapic_state)))
                        goto out;
                r = 0;
                break;
        }
        case KVM_SET_LAPIC: {
                r = -EINVAL;
                if (!vcpu->arch.apic)
                        goto out;
                u.lapic = memdup_user(argp, sizeof(*u.lapic));
                if (IS_ERR(u.lapic))
                        return PTR_ERR(u.lapic);

                r = kvm_vcpu_ioctl_set_lapic(vcpu, u.lapic);
                break;
        }
        case KVM_INTERRUPT: {
                struct kvm_interrupt irq;

                r = -EFAULT;
                if (copy_from_user(&irq, argp, sizeof irq))
                        goto out;
                r = kvm_vcpu_ioctl_interrupt(vcpu, &irq);
                break;
        }
        case KVM_NMI: {
                r = kvm_vcpu_ioctl_nmi(vcpu);
                break;
        }
        case KVM_SMI: {
                r = kvm_vcpu_ioctl_smi(vcpu);
                break;
        }
        case KVM_SET_CPUID: {
                struct kvm_cpuid __user *cpuid_arg = argp;
                struct kvm_cpuid cpuid;

                r = -EFAULT;
                if (copy_from_user(&cpuid, cpuid_arg, sizeof cpuid))
                        goto out;
                r = kvm_vcpu_ioctl_set_cpuid(vcpu, &cpuid, cpuid_arg->entries);
                break;
        }
        case KVM_SET_CPUID2: {
                struct kvm_cpuid2 __user *cpuid_arg = argp;
                struct kvm_cpuid2 cpuid;

                r = -EFAULT;
                if (copy_from_user(&cpuid, cpuid_arg, sizeof cpuid))
                        goto out;
                r = kvm_vcpu_ioctl_set_cpuid2(vcpu, &cpuid,
                                              cpuid_arg->entries);
                break;
        }
        case KVM_GET_CPUID2: {
                struct kvm_cpuid2 __user *cpuid_arg = argp;
                struct kvm_cpuid2 cpuid;

                r = -EFAULT;
                if (copy_from_user(&cpuid, cpuid_arg, sizeof cpuid))
                        goto out;
                r = kvm_vcpu_ioctl_get_cpuid2(vcpu, &cpuid,
                                              cpuid_arg->entries);
                if (r)
                        goto out;
                r = -EFAULT;
                if (copy_to_user(cpuid_arg, &cpuid, sizeof cpuid))
                        goto out;
                r = 0;
                break;
        }
        case KVM_GET_MSRS:
                r = msr_io(vcpu, argp, do_get_msr, 1);
                break;
        case KVM_SET_MSRS:
                r = msr_io(vcpu, argp, do_set_msr, 0);
                break;
        case KVM_TPR_ACCESS_REPORTING: {
                struct kvm_tpr_access_ctl tac;

                r = -EFAULT;
                if (copy_from_user(&tac, argp, sizeof tac))
                        goto out;
                r = vcpu_ioctl_tpr_access_reporting(vcpu, &tac);
                if (r)
                        goto out;
                r = -EFAULT;
                if (copy_to_user(argp, &tac, sizeof tac))
                        goto out;
                r = 0;
                break;
        };
        case KVM_SET_VAPIC_ADDR: {
                struct kvm_vapic_addr va;

                r = -EINVAL;
                if (!irqchip_in_kernel(vcpu->kvm))
                        goto out;
                r = -EFAULT;
                if (copy_from_user(&va, argp, sizeof va))
                        goto out;
                r = kvm_lapic_set_vapic_addr(vcpu, va.vapic_addr);
                break;
        }
        case KVM_X86_SETUP_MCE: {
                u64 mcg_cap;

                r = -EFAULT;
                if (copy_from_user(&mcg_cap, argp, sizeof mcg_cap))
                        goto out;
                r = kvm_vcpu_ioctl_x86_setup_mce(vcpu, mcg_cap);
                break;
        }
        case KVM_X86_SET_MCE: {
                struct kvm_x86_mce mce;

                r = -EFAULT;
                if (copy_from_user(&mce, argp, sizeof mce))
                        goto out;
                r = kvm_vcpu_ioctl_x86_set_mce(vcpu, &mce);
                break;
        }
        case KVM_GET_VCPU_EVENTS: {
                struct kvm_vcpu_events events;

                kvm_vcpu_ioctl_x86_get_vcpu_events(vcpu, &events);

                r = -EFAULT;
                if (copy_to_user(argp, &events, sizeof(struct kvm_vcpu_events)))
                        break;
                r = 0;
                break;
        }
        case KVM_SET_VCPU_EVENTS: {
                struct kvm_vcpu_events events;

                r = -EFAULT;
                if (copy_from_user(&events, argp, sizeof(struct kvm_vcpu_events)))
                        break;

                r = kvm_vcpu_ioctl_x86_set_vcpu_events(vcpu, &events);
                break;
        }
        case KVM_GET_DEBUGREGS: {
                struct kvm_debugregs dbgregs;

                kvm_vcpu_ioctl_x86_get_debugregs(vcpu, &dbgregs);

                r = -EFAULT;
                if (copy_to_user(argp, &dbgregs,
                                 sizeof(struct kvm_debugregs)))
                        break;
                r = 0;
                break;
        }
        case KVM_SET_DEBUGREGS: {
                struct kvm_debugregs dbgregs;

                r = -EFAULT;
                if (copy_from_user(&dbgregs, argp,
                                   sizeof(struct kvm_debugregs)))
                        break;

                r = kvm_vcpu_ioctl_x86_set_debugregs(vcpu, &dbgregs);
                break;
        }
        case KVM_GET_XSAVE: {
                u.xsave = kzalloc(sizeof(struct kvm_xsave), GFP_KERNEL);
                r = -ENOMEM;
                if (!u.xsave)
                        break;

                kvm_vcpu_ioctl_x86_get_xsave(vcpu, u.xsave);

                r = -EFAULT;
                if (copy_to_user(argp, u.xsave, sizeof(struct kvm_xsave)))
                        break;
                r = 0;
                break;
        }
        case KVM_SET_XSAVE: {
                u.xsave = memdup_user(argp, sizeof(*u.xsave));
                if (IS_ERR(u.xsave))
                        return PTR_ERR(u.xsave);

                r = kvm_vcpu_ioctl_x86_set_xsave(vcpu, u.xsave);
                break;
        }
        case KVM_GET_XCRS: {
                u.xcrs = kzalloc(sizeof(struct kvm_xcrs), GFP_KERNEL);
                r = -ENOMEM;
                if (!u.xcrs)
                        break;

                kvm_vcpu_ioctl_x86_get_xcrs(vcpu, u.xcrs);

                r = -EFAULT;
                if (copy_to_user(argp, u.xcrs,
                                 sizeof(struct kvm_xcrs)))
                        break;
                r = 0;
                break;
        }
        case KVM_SET_XCRS: {
                u.xcrs = memdup_user(argp, sizeof(*u.xcrs));
                if (IS_ERR(u.xcrs))
                        return PTR_ERR(u.xcrs);

                r = kvm_vcpu_ioctl_x86_set_xcrs(vcpu, u.xcrs);
                break;
        }
        case KVM_SET_TSC_KHZ: {
                u32 user_tsc_khz;

                r = -EINVAL;
                user_tsc_khz = (u32)arg;

                if (user_tsc_khz >= kvm_max_guest_tsc_khz)
                        goto out;

                if (user_tsc_khz == 0)
                        user_tsc_khz = tsc_khz;

                kvm_set_tsc_khz(vcpu, user_tsc_khz);

                r = 0;
                goto out;
        }
        case KVM_GET_TSC_KHZ: {
                r = vcpu->arch.virtual_tsc_khz;
                goto out;
        }
        case KVM_KVMCLOCK_CTRL: {
                r = kvm_set_guest_paused(vcpu);
                goto out;
        }
        default:
                r = -EINVAL;
        }
out:
        kfree(u.buffer);
        return r;
}

int kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
{
        return VM_FAULT_SIGBUS;
}

static int kvm_vm_ioctl_set_tss_addr(struct kvm *kvm, unsigned long addr)
{
        int ret;

        if (addr > (unsigned int)(-3 * PAGE_SIZE))
                return -EINVAL;
        ret = kvm_x86_ops->set_tss_addr(kvm, addr);
        return ret;
}

static int kvm_vm_ioctl_set_identity_map_addr(struct kvm *kvm,
                                              u64 ident_addr)
{
        kvm->arch.ept_identity_map_addr = ident_addr;
        return 0;
}

static int kvm_vm_ioctl_set_nr_mmu_pages(struct kvm *kvm,
                                          u32 kvm_nr_mmu_pages)
{
        if (kvm_nr_mmu_pages < KVM_MIN_ALLOC_MMU_PAGES)
                return -EINVAL;

        mutex_lock(&kvm->slots_lock);

        kvm_mmu_change_mmu_pages(kvm, kvm_nr_mmu_pages);
        kvm->arch.n_requested_mmu_pages = kvm_nr_mmu_pages;

        mutex_unlock(&kvm->slots_lock);
        return 0;
}

static int kvm_vm_ioctl_get_nr_mmu_pages(struct kvm *kvm)
{
        return kvm->arch.n_max_mmu_pages;
}

static int kvm_vm_ioctl_get_irqchip(struct kvm *kvm, struct kvm_irqchip *chip)
{
        int r;

        r = 0;
        switch (chip->chip_id) {
        case KVM_IRQCHIP_PIC_MASTER:
                memcpy(&chip->chip.pic,
                        &pic_irqchip(kvm)->pics[0],
                        sizeof(struct kvm_pic_state));
                break;
        case KVM_IRQCHIP_PIC_SLAVE:
                memcpy(&chip->chip.pic,
                        &pic_irqchip(kvm)->pics[1],
                        sizeof(struct kvm_pic_state));
                break;
        case KVM_IRQCHIP_IOAPIC:
                r = kvm_get_ioapic(kvm, &chip->chip.ioapic);
                break;
        default:
                r = -EINVAL;
                break;
        }
        return r;
}

static int kvm_vm_ioctl_set_irqchip(struct kvm *kvm, struct kvm_irqchip *chip)
{
        int r;

        r = 0;
        switch (chip->chip_id) {
        case KVM_IRQCHIP_PIC_MASTER:
                spin_lock(&pic_irqchip(kvm)->lock);
                memcpy(&pic_irqchip(kvm)->pics[0],
                        &chip->chip.pic,
                        sizeof(struct kvm_pic_state));
                spin_unlock(&pic_irqchip(kvm)->lock);
                break;
        case KVM_IRQCHIP_PIC_SLAVE:
                spin_lock(&pic_irqchip(kvm)->lock);
                memcpy(&pic_irqchip(kvm)->pics[1],
                        &chip->chip.pic,
                        sizeof(struct kvm_pic_state));
                spin_unlock(&pic_irqchip(kvm)->lock);
                break;
        case KVM_IRQCHIP_IOAPIC:
                r = kvm_set_ioapic(kvm, &chip->chip.ioapic);
                break;
        default:
                r = -EINVAL;
                break;
        }
        kvm_pic_update_irq(pic_irqchip(kvm));
        return r;
}

static int kvm_vm_ioctl_get_pit(struct kvm *kvm, struct kvm_pit_state *ps)
{
        int r = 0;

        mutex_lock(&kvm->arch.vpit->pit_state.lock);
        memcpy(ps, &kvm->arch.vpit->pit_state, sizeof(struct kvm_pit_state));
        mutex_unlock(&kvm->arch.vpit->pit_state.lock);
        return r;
}

static int kvm_vm_ioctl_set_pit(struct kvm *kvm, struct kvm_pit_state *ps)
{
        int r = 0;

        mutex_lock(&kvm->arch.vpit->pit_state.lock);
        memcpy(&kvm->arch.vpit->pit_state, ps, sizeof(struct kvm_pit_state));
        kvm_pit_load_count(kvm, 0, ps->channels[0].count, 0);
        mutex_unlock(&kvm->arch.vpit->pit_state.lock);
        return r;
}

static int kvm_vm_ioctl_get_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps)
{
        int r = 0;

        mutex_lock(&kvm->arch.vpit->pit_state.lock);
        memcpy(ps->channels, &kvm->arch.vpit->pit_state.channels,
                sizeof(ps->channels));
        ps->flags = kvm->arch.vpit->pit_state.flags;
        mutex_unlock(&kvm->arch.vpit->pit_state.lock);
        memset(&ps->reserved, 0, sizeof(ps->reserved));
        return r;
}

static int kvm_vm_ioctl_set_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps)
{
        int r = 0, start = 0;
        u32 prev_legacy, cur_legacy;
        mutex_lock(&kvm->arch.vpit->pit_state.lock);
        prev_legacy = kvm->arch.vpit->pit_state.flags & KVM_PIT_FLAGS_HPET_LEGACY;
        cur_legacy = ps->flags & KVM_PIT_FLAGS_HPET_LEGACY;
        if (!prev_legacy && cur_legacy)
                start = 1;
        memcpy(&kvm->arch.vpit->pit_state.channels, &ps->channels,
               sizeof(kvm->arch.vpit->pit_state.channels));
        kvm->arch.vpit->pit_state.flags = ps->flags;
        kvm_pit_load_count(kvm, 0, kvm->arch.vpit->pit_state.channels[0].count, start);
        mutex_unlock(&kvm->arch.vpit->pit_state.lock);
        return r;
}

static int kvm_vm_ioctl_reinject(struct kvm *kvm,
                                 struct kvm_reinject_control *control)
{
        if (!kvm->arch.vpit)
                return -ENXIO;
        mutex_lock(&kvm->arch.vpit->pit_state.lock);
        kvm->arch.vpit->pit_state.reinject = control->pit_reinject;
        mutex_unlock(&kvm->arch.vpit->pit_state.lock);
        return 0;
}

/**
 * kvm_vm_ioctl_get_dirty_log - get and clear the log of dirty pages in a slot
 * @kvm: kvm instance
 * @log: slot id and address to which we copy the log
 *
 * Steps 1-4 below provide general overview of dirty page logging. See
 * kvm_get_dirty_log_protect() function description for additional details.
 *
 * We call kvm_get_dirty_log_protect() to handle steps 1-3, upon return we
 * always flush the TLB (step 4) even if previous step failed  and the dirty
 * bitmap may be corrupt. Regardless of previous outcome the KVM logging API
 * does not preclude user space subsequent dirty log read. Flushing TLB ensures
 * writes will be marked dirty for next log read.
 *
 *   1. Take a snapshot of the bit and clear it if needed.
 *   2. Write protect the corresponding page.
 *   3. Copy the snapshot to the userspace.
 *   4. Flush TLB's if needed.
 */
int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
{
        bool is_dirty = false;
        int r;

        mutex_lock(&kvm->slots_lock);

        /*
         * Flush potentially hardware-cached dirty pages to dirty_bitmap.
         */
        if (kvm_x86_ops->flush_log_dirty)
                kvm_x86_ops->flush_log_dirty(kvm);

        r = kvm_get_dirty_log_protect(kvm, log, &is_dirty);

        /*
         * All the TLBs can be flushed out of mmu lock, see the comments in
         * kvm_mmu_slot_remove_write_access().
         */
        lockdep_assert_held(&kvm->slots_lock);
        if (is_dirty)
                kvm_flush_remote_tlbs(kvm);

        mutex_unlock(&kvm->slots_lock);
        return r;
}

int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_event,
                        bool line_status)
{
        if (!irqchip_in_kernel(kvm))
                return -ENXIO;

        irq_event->status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
                                        irq_event->irq, irq_event->level,
                                        line_status);
        return 0;
}

static int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
                                   struct kvm_enable_cap *cap)
{
        int r;

        if (cap->flags)
                return -EINVAL;

        switch (cap->cap) {
        case KVM_CAP_DISABLE_QUIRKS:
                kvm->arch.disabled_quirks = cap->args[0];
                r = 0;
                break;
        default:
                r = -EINVAL;
                break;
        }
        return r;
}

long kvm_arch_vm_ioctl(struct file *filp,
                       unsigned int ioctl, unsigned long arg)
{
        struct kvm *kvm = filp->private_data;
        void __user *argp = (void __user *)arg;
        int r = -ENOTTY;
        /*
         * This union makes it completely explicit to gcc-3.x
         * that these two variables' stack usage should be
         * combined, not added together.
         */
        union {
                struct kvm_pit_state ps;
                struct kvm_pit_state2 ps2;
                struct kvm_pit_config pit_config;
        } u;

        switch (ioctl) {
        case KVM_SET_TSS_ADDR:
                r = kvm_vm_ioctl_set_tss_addr(kvm, arg);
                break;
        case KVM_SET_IDENTITY_MAP_ADDR: {
                u64 ident_addr;

                r = -EFAULT;
                if (copy_from_user(&ident_addr, argp, sizeof ident_addr))
                        goto out;
                r = kvm_vm_ioctl_set_identity_map_addr(kvm, ident_addr);
                break;
        }
        case KVM_SET_NR_MMU_PAGES:
                r = kvm_vm_ioctl_set_nr_mmu_pages(kvm, arg);
                break;
        case KVM_GET_NR_MMU_PAGES:
                r = kvm_vm_ioctl_get_nr_mmu_pages(kvm);
                break;
        case KVM_CREATE_IRQCHIP: {
                struct kvm_pic *vpic;

                mutex_lock(&kvm->lock);
                r = -EEXIST;
                if (kvm->arch.vpic)
                        goto create_irqchip_unlock;
                r = -EINVAL;
                if (atomic_read(&kvm->online_vcpus))
                        goto create_irqchip_unlock;
                r = -ENOMEM;
                vpic = kvm_create_pic(kvm);
                if (vpic) {
                        r = kvm_ioapic_init(kvm);
                        if (r) {
                                mutex_lock(&kvm->slots_lock);
                                kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS,
                                                          &vpic->dev_master);
                                kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS,
                                                          &vpic->dev_slave);
                                kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS,
                                                          &vpic->dev_eclr);
                                mutex_unlock(&kvm->slots_lock);
                                kfree(vpic);
                                goto create_irqchip_unlock;
                        }
                } else
                        goto create_irqchip_unlock;
                smp_wmb();
                kvm->arch.vpic = vpic;
                smp_wmb();
                r = kvm_setup_default_irq_routing(kvm);
                if (r) {
                        mutex_lock(&kvm->slots_lock);
                        mutex_lock(&kvm->irq_lock);
                        kvm_ioapic_destroy(kvm);
                        kvm_destroy_pic(kvm);
                        mutex_unlock(&kvm->irq_lock);
                        mutex_unlock(&kvm->slots_lock);
                }
        create_irqchip_unlock:
                mutex_unlock(&kvm->lock);
                break;
        }
        case KVM_CREATE_PIT:
                u.pit_config.flags = KVM_PIT_SPEAKER_DUMMY;
                goto create_pit;
        case KVM_CREATE_PIT2:
                r = -EFAULT;
                if (copy_from_user(&u.pit_config, argp,
                                   sizeof(struct kvm_pit_config)))
                        goto out;
        create_pit:
                mutex_lock(&kvm->slots_lock);
                r = -EEXIST;
                if (kvm->arch.vpit)
                        goto create_pit_unlock;
                r = -ENOMEM;
                kvm->arch.vpit = kvm_create_pit(kvm, u.pit_config.flags);
                if (kvm->arch.vpit)
                        r = 0;
        create_pit_unlock:
                mutex_unlock(&kvm->slots_lock);
                break;
        case KVM_GET_IRQCHIP: {
                /* 0: PIC master, 1: PIC slave, 2: IOAPIC */
                struct kvm_irqchip *chip;

                chip = memdup_user(argp, sizeof(*chip));
                if (IS_ERR(chip)) {
                        r = PTR_ERR(chip);
                        goto out;
                }

                r = -ENXIO;
                if (!irqchip_in_kernel(kvm))
                        goto get_irqchip_out;
                r = kvm_vm_ioctl_get_irqchip(kvm, chip);
                if (r)
                        goto get_irqchip_out;
                r = -EFAULT;
                if (copy_to_user(argp, chip, sizeof *chip))
                        goto get_irqchip_out;
                r = 0;
        get_irqchip_out:
                kfree(chip);
                break;
        }
        case KVM_SET_IRQCHIP: {
                /* 0: PIC master, 1: PIC slave, 2: IOAPIC */
                struct kvm_irqchip *chip;

                chip = memdup_user(argp, sizeof(*chip));
                if (IS_ERR(chip)) {
                        r = PTR_ERR(chip);
                        goto out;
                }

                r = -ENXIO;
                if (!irqchip_in_kernel(kvm))
                        goto set_irqchip_out;
                r = kvm_vm_ioctl_set_irqchip(kvm, chip);
                if (r)
                        goto set_irqchip_out;
                r = 0;
        set_irqchip_out:
                kfree(chip);
                break;
        }
        case KVM_GET_PIT: {
                r = -EFAULT;
                if (copy_from_user(&u.ps, argp, sizeof(struct kvm_pit_state)))
                        goto out;
                r = -ENXIO;
                if (!kvm->arch.vpit)
                        goto out;
                r = kvm_vm_ioctl_get_pit(kvm, &u.ps);
                if (r)
                        goto out;
                r = -EFAULT;
                if (copy_to_user(argp, &u.ps, sizeof(struct kvm_pit_state)))
                        goto out;
                r = 0;
                break;
        }
        case KVM_SET_PIT: {
                r = -EFAULT;
                if (copy_from_user(&u.ps, argp, sizeof u.ps))
                        goto out;
                r = -ENXIO;
                if (!kvm->arch.vpit)
                        goto out;
                r = kvm_vm_ioctl_set_pit(kvm, &u.ps);
                break;
        }
        case KVM_GET_PIT2: {
                r = -ENXIO;
                if (!kvm->arch.vpit)
                        goto out;
                r = kvm_vm_ioctl_get_pit2(kvm, &u.ps2);
                if (r)
                        goto out;
                r = -EFAULT;
                if (copy_to_user(argp, &u.ps2, sizeof(u.ps2)))
                        goto out;
                r = 0;
                break;
        }
        case KVM_SET_PIT2: {
                r = -EFAULT;
                if (copy_from_user(&u.ps2, argp, sizeof(u.ps2)))
                        goto out;
                r = -ENXIO;
                if (!kvm->arch.vpit)
                        goto out;
                r = kvm_vm_ioctl_set_pit2(kvm, &u.ps2);
                break;
        }
        case KVM_REINJECT_CONTROL: {
                struct kvm_reinject_control control;
                r =  -EFAULT;
                if (copy_from_user(&control, argp, sizeof(control)))
                        goto out;
                r = kvm_vm_ioctl_reinject(kvm, &control);
                break;
        }
        case KVM_XEN_HVM_CONFIG: {
                r = -EFAULT;
                if (copy_from_user(&kvm->arch.xen_hvm_config, argp,
                                   sizeof(struct kvm_xen_hvm_config)))
                        goto out;
                r = -EINVAL;
                if (kvm->arch.xen_hvm_config.flags)
                        goto out;
                r = 0;
                break;
        }
        case KVM_SET_CLOCK: {
                struct kvm_clock_data user_ns;
                u64 now_ns;
                s64 delta;

                r = -EFAULT;
                if (copy_from_user(&user_ns, argp, sizeof(user_ns)))
                        goto out;

                r = -EINVAL;
                if (user_ns.flags)
                        goto out;

                r = 0;
                local_irq_disable();
                now_ns = get_kernel_ns();
                delta = user_ns.clock - now_ns;
                local_irq_enable();
                kvm->arch.kvmclock_offset = delta;
                kvm_gen_update_masterclock(kvm);
                break;
        }
        case KVM_GET_CLOCK: {
                struct kvm_clock_data user_ns;
                u64 now_ns;

                local_irq_disable();
                now_ns = get_kernel_ns();
                user_ns.clock = kvm->arch.kvmclock_offset + now_ns;
                local_irq_enable();
                user_ns.flags = 0;
                memset(&user_ns.pad, 0, sizeof(user_ns.pad));

                r = -EFAULT;
                if (copy_to_user(argp, &user_ns, sizeof(user_ns)))
                        goto out;
                r = 0;
                break;
        }
        case KVM_ENABLE_CAP: {
                struct kvm_enable_cap cap;

                r = -EFAULT;
                if (copy_from_user(&cap, argp, sizeof(cap)))
                        goto out;
                r = kvm_vm_ioctl_enable_cap(kvm, &cap);
                break;
        }
        default:
                r = kvm_vm_ioctl_assigned_device(kvm, ioctl, arg);
        }
out:
        return r;
}

static void kvm_init_msr_list(void)
{
        u32 dummy[2];
        unsigned i, j;

        for (i = j = 0; i < ARRAY_SIZE(msrs_to_save); i++) {
                if (rdmsr_safe(msrs_to_save[i], &dummy[0], &dummy[1]) < 0)
                        continue;

                /*
                 * Even MSRs that are valid in the host may not be exposed
                 * to the guests in some cases.  We could work around this
                 * in VMX with the generic MSR save/load machinery, but it
                 * is not really worthwhile since it will really only
                 * happen with nested virtualization.
                 */
                switch (msrs_to_save[i]) {
                case MSR_IA32_BNDCFGS:
                        if (!kvm_x86_ops->mpx_supported())
                                continue;
                        break;
                default:
                        break;
                }

                if (j < i)
                        msrs_to_save[j] = msrs_to_save[i];
                j++;
        }
        num_msrs_to_save = j;

        for (i = j = 0; i < ARRAY_SIZE(emulated_msrs); i++) {
                switch (emulated_msrs[i]) {
                case MSR_IA32_SMBASE:
                        if (!kvm_x86_ops->cpu_has_high_real_mode_segbase())
                                continue;
                        break;
                default:
                        break;
                }

                if (j < i)
                        emulated_msrs[j] = emulated_msrs[i];
                j++;
        }
        num_emulated_msrs = j;
}

static int vcpu_mmio_write(struct kvm_vcpu *vcpu, gpa_t addr, int len,
                           const void *v)
{
        int handled = 0;
        int n;

        do {
                n = min(len, 8);
                if (!(vcpu->arch.apic &&
                      !kvm_iodevice_write(vcpu, &vcpu->arch.apic->dev, addr, n, v))
                    && kvm_io_bus_write(vcpu, KVM_MMIO_BUS, addr, n, v))
                        break;
                handled += n;
                addr += n;
                len -= n;
                v += n;
        } while (len);

        return handled;
}

static int vcpu_mmio_read(struct kvm_vcpu *vcpu, gpa_t addr, int len, void *v)
{
        int handled = 0;
        int n;

        do {
                n = min(len, 8);
                if (!(vcpu->arch.apic &&
                      !kvm_iodevice_read(vcpu, &vcpu->arch.apic->dev,
                                         addr, n, v))
                    && kvm_io_bus_read(vcpu, KVM_MMIO_BUS, addr, n, v))
                        break;
                trace_kvm_mmio(KVM_TRACE_MMIO_READ, n, addr, *(u64 *)v);
                handled += n;
                addr += n;
                len -= n;
                v += n;
        } while (len);

        return handled;
}

static void kvm_set_segment(struct kvm_vcpu *vcpu,
                        struct kvm_segment *var, int seg)
{
        kvm_x86_ops->set_segment(vcpu, var, seg);
}

void kvm_get_segment(struct kvm_vcpu *vcpu,
                     struct kvm_segment *var, int seg)
{
        kvm_x86_ops->get_segment(vcpu, var, seg);
}

gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access,
                           struct x86_exception *exception)
{
        gpa_t t_gpa;

        BUG_ON(!mmu_is_nested(vcpu));

        /* NPT walks are always user-walks */
        access |= PFERR_USER_MASK;
        t_gpa  = vcpu->arch.mmu.gva_to_gpa(vcpu, gpa, access, exception);

        return t_gpa;
}

gpa_t kvm_mmu_gva_to_gpa_read(struct kvm_vcpu *vcpu, gva_t gva,
                              struct x86_exception *exception)
{
        u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
        return vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, access, exception);
}

 gpa_t kvm_mmu_gva_to_gpa_fetch(struct kvm_vcpu *vcpu, gva_t gva,
                                struct x86_exception *exception)
{
        u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
        access |= PFERR_FETCH_MASK;
        return vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, access, exception);
}

gpa_t kvm_mmu_gva_to_gpa_write(struct kvm_vcpu *vcpu, gva_t gva,
                               struct x86_exception *exception)
{
        u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
        access |= PFERR_WRITE_MASK;
        return vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, access, exception);
}

/* uses this to access any guest's mapped memory without checking CPL */
gpa_t kvm_mmu_gva_to_gpa_system(struct kvm_vcpu *vcpu, gva_t gva,
                                struct x86_exception *exception)
{
        return vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, 0, exception);
}

static int kvm_read_guest_virt_helper(gva_t addr, void *val, unsigned int bytes,
                                      struct kvm_vcpu *vcpu, u32 access,
                                      struct x86_exception *exception)
{
        void *data = val;
        int r = X86EMUL_CONTINUE;

        while (bytes) {
                gpa_t gpa = vcpu->arch.walk_mmu->gva_to_gpa(vcpu, addr, access,
                                                            exception);
                unsigned offset = addr & (PAGE_SIZE-1);
                unsigned toread = min(bytes, (unsigned)PAGE_SIZE - offset);
                int ret;

                if (gpa == UNMAPPED_GVA)
                        return X86EMUL_PROPAGATE_FAULT;
                ret = kvm_vcpu_read_guest_page(vcpu, gpa >> PAGE_SHIFT, data,
                                               offset, toread);
                if (ret < 0) {
                        r = X86EMUL_IO_NEEDED;
                        goto out;
                }

                bytes -= toread;
                data += toread;
                addr += toread;
        }
out:
        return r;
}

/* used for instruction fetching */
static int kvm_fetch_guest_virt(struct x86_emulate_ctxt *ctxt,
                                gva_t addr, void *val, unsigned int bytes,
                                struct x86_exception *exception)
{
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
        u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
        unsigned offset;
        int ret;

        /* Inline kvm_read_guest_virt_helper for speed.  */
        gpa_t gpa = vcpu->arch.walk_mmu->gva_to_gpa(vcpu, addr, access|PFERR_FETCH_MASK,
                                                    exception);
        if (unlikely(gpa == UNMAPPED_GVA))
                return X86EMUL_PROPAGATE_FAULT;

        offset = addr & (PAGE_SIZE-1);
        if (WARN_ON(offset + bytes > PAGE_SIZE))
                bytes = (unsigned)PAGE_SIZE - offset;
        ret = kvm_vcpu_read_guest_page(vcpu, gpa >> PAGE_SHIFT, val,
                                       offset, bytes);
        if (unlikely(ret < 0))
                return X86EMUL_IO_NEEDED;

        return X86EMUL_CONTINUE;
}

int kvm_read_guest_virt(struct x86_emulate_ctxt *ctxt,
                               gva_t addr, void *val, unsigned int bytes,
                               struct x86_exception *exception)
{
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
        u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;

        return kvm_read_guest_virt_helper(addr, val, bytes, vcpu, access,
                                          exception);
}
EXPORT_SYMBOL_GPL(kvm_read_guest_virt);

static int kvm_read_guest_virt_system(struct x86_emulate_ctxt *ctxt,
                                      gva_t addr, void *val, unsigned int bytes,
                                      struct x86_exception *exception)
{
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
        return kvm_read_guest_virt_helper(addr, val, bytes, vcpu, 0, exception);
}

int kvm_write_guest_virt_system(struct x86_emulate_ctxt *ctxt,
                                       gva_t addr, void *val,
                                       unsigned int bytes,
                                       struct x86_exception *exception)
{
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
        void *data = val;
        int r = X86EMUL_CONTINUE;

        while (bytes) {
                gpa_t gpa =  vcpu->arch.walk_mmu->gva_to_gpa(vcpu, addr,
                                                             PFERR_WRITE_MASK,
                                                             exception);
                unsigned offset = addr & (PAGE_SIZE-1);
                unsigned towrite = min(bytes, (unsigned)PAGE_SIZE - offset);
                int ret;

                if (gpa == UNMAPPED_GVA)
                        return X86EMUL_PROPAGATE_FAULT;
                ret = kvm_vcpu_write_guest(vcpu, gpa, data, towrite);
                if (ret < 0) {
                        r = X86EMUL_IO_NEEDED;
                        goto out;
                }

                bytes -= towrite;
                data += towrite;
                addr += towrite;
        }
out:
        return r;
}
EXPORT_SYMBOL_GPL(kvm_write_guest_virt_system);

static int vcpu_mmio_gva_to_gpa(struct kvm_vcpu *vcpu, unsigned long gva,
                                gpa_t *gpa, struct x86_exception *exception,
                                bool write)
{
        u32 access = ((kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0)
                | (write ? PFERR_WRITE_MASK : 0);

        if (vcpu_match_mmio_gva(vcpu, gva)
            && !permission_fault(vcpu, vcpu->arch.walk_mmu,
                                 vcpu->arch.access, access)) {
                *gpa = vcpu->arch.mmio_gfn << PAGE_SHIFT |
                                        (gva & (PAGE_SIZE - 1));
                trace_vcpu_match_mmio(gva, *gpa, write, false);
                return 1;
        }

        *gpa = vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, access, exception);

        if (*gpa == UNMAPPED_GVA)
                return -1;

        /* For APIC access vmexit */
        if ((*gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE)
                return 1;

        if (vcpu_match_mmio_gpa(vcpu, *gpa)) {
                trace_vcpu_match_mmio(gva, *gpa, write, true);
                return 1;
        }

        return 0;
}

int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
                        const void *val, int bytes)
{
        int ret;

        ret = kvm_vcpu_write_guest(vcpu, gpa, val, bytes);
        if (ret < 0)
                return 0;
        kvm_mmu_pte_write(vcpu, gpa, val, bytes);
        return 1;
}

struct read_write_emulator_ops {
        int (*read_write_prepare)(struct kvm_vcpu *vcpu, void *val,
                                  int bytes);
        int (*read_write_emulate)(struct kvm_vcpu *vcpu, gpa_t gpa,
                                  void *val, int bytes);
        int (*read_write_mmio)(struct kvm_vcpu *vcpu, gpa_t gpa,
                               int bytes, void *val);
        int (*read_write_exit_mmio)(struct kvm_vcpu *vcpu, gpa_t gpa,
                                    void *val, int bytes);
        bool write;
};

static int read_prepare(struct kvm_vcpu *vcpu, void *val, int bytes)
{
        if (vcpu->mmio_read_completed) {
                trace_kvm_mmio(KVM_TRACE_MMIO_READ, bytes,
                               vcpu->mmio_fragments[0].gpa, *(u64 *)val);
                vcpu->mmio_read_completed = 0;
                return 1;
        }

        return 0;
}

static int read_emulate(struct kvm_vcpu *vcpu, gpa_t gpa,
                        void *val, int bytes)
{
        return !kvm_vcpu_read_guest(vcpu, gpa, val, bytes);
}

static int write_emulate(struct kvm_vcpu *vcpu, gpa_t gpa,
                         void *val, int bytes)
{
        return emulator_write_phys(vcpu, gpa, val, bytes);
}

static int write_mmio(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes, void *val)
{
        trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, bytes, gpa, *(u64 *)val);
        return vcpu_mmio_write(vcpu, gpa, bytes, val);
}

static int read_exit_mmio(struct kvm_vcpu *vcpu, gpa_t gpa,
                          void *val, int bytes)
{
        trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, bytes, gpa, 0);
        return X86EMUL_IO_NEEDED;
}

static int write_exit_mmio(struct kvm_vcpu *vcpu, gpa_t gpa,
                           void *val, int bytes)
{
        struct kvm_mmio_fragment *frag = &vcpu->mmio_fragments[0];

        memcpy(vcpu->run->mmio.data, frag->data, min(8u, frag->len));
        return X86EMUL_CONTINUE;
}

static const struct read_write_emulator_ops read_emultor = {
        .read_write_prepare = read_prepare,
        .read_write_emulate = read_emulate,
        .read_write_mmio = vcpu_mmio_read,
        .read_write_exit_mmio = read_exit_mmio,
};

static const struct read_write_emulator_ops write_emultor = {
        .read_write_emulate = write_emulate,
        .read_write_mmio = write_mmio,
        .read_write_exit_mmio = write_exit_mmio,
        .write = true,
};

static int emulator_read_write_onepage(unsigned long addr, void *val,
                                       unsigned int bytes,
                                       struct x86_exception *exception,
                                       struct kvm_vcpu *vcpu,
                                       const struct read_write_emulator_ops *ops)
{
        gpa_t gpa;
        int handled, ret;
        bool write = ops->write;
        struct kvm_mmio_fragment *frag;

        ret = vcpu_mmio_gva_to_gpa(vcpu, addr, &gpa, exception, write);

        if (ret < 0)
                return X86EMUL_PROPAGATE_FAULT;

        /* For APIC access vmexit */
        if (ret)
                goto mmio;

        if (ops->read_write_emulate(vcpu, gpa, val, bytes))
                return X86EMUL_CONTINUE;

mmio:
        /*
         * Is this MMIO handled locally?
         */
        handled = ops->read_write_mmio(vcpu, gpa, bytes, val);
        if (handled == bytes)
                return X86EMUL_CONTINUE;

        gpa += handled;
        bytes -= handled;
        val += handled;

        WARN_ON(vcpu->mmio_nr_fragments >= KVM_MAX_MMIO_FRAGMENTS);
        frag = &vcpu->mmio_fragments[vcpu->mmio_nr_fragments++];
        frag->gpa = gpa;
        frag->data = val;
        frag->len = bytes;
        return X86EMUL_CONTINUE;
}

static int emulator_read_write(struct x86_emulate_ctxt *ctxt,
                        unsigned long addr,
                        void *val, unsigned int bytes,
                        struct x86_exception *exception,
                        const struct read_write_emulator_ops *ops)
{
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
        gpa_t gpa;
        int rc;

        if (ops->read_write_prepare &&
                  ops->read_write_prepare(vcpu, val, bytes))
                return X86EMUL_CONTINUE;

        vcpu->mmio_nr_fragments = 0;

        /* Crossing a page boundary? */
        if (((addr + bytes - 1) ^ addr) & PAGE_MASK) {
                int now;

                now = -addr & ~PAGE_MASK;
                rc = emulator_read_write_onepage(addr, val, now, exception,
                                                 vcpu, ops);

                if (rc != X86EMUL_CONTINUE)
                        return rc;
                addr += now;
                if (ctxt->mode != X86EMUL_MODE_PROT64)
                        addr = (u32)addr;
                val += now;
                bytes -= now;
        }

        rc = emulator_read_write_onepage(addr, val, bytes, exception,
                                         vcpu, ops);
        if (rc != X86EMUL_CONTINUE)
                return rc;

        if (!vcpu->mmio_nr_fragments)
                return rc;

        gpa = vcpu->mmio_fragments[0].gpa;

        vcpu->mmio_needed = 1;
        vcpu->mmio_cur_fragment = 0;

        vcpu->run->mmio.len = min(8u, vcpu->mmio_fragments[0].len);
        vcpu->run->mmio.is_write = vcpu->mmio_is_write = ops->write;
        vcpu->run->exit_reason = KVM_EXIT_MMIO;
        vcpu->run->mmio.phys_addr = gpa;

        return ops->read_write_exit_mmio(vcpu, gpa, val, bytes);
}

static int emulator_read_emulated(struct x86_emulate_ctxt *ctxt,
                                  unsigned long addr,
                                  void *val,
                                  unsigned int bytes,
                                  struct x86_exception *exception)
{
        return emulator_read_write(ctxt, addr, val, bytes,
                                   exception, &read_emultor);
}

static int emulator_write_emulated(struct x86_emulate_ctxt *ctxt,
                            unsigned long addr,
                            const void *val,
                            unsigned int bytes,
                            struct x86_exception *exception)
{
        return emulator_read_write(ctxt, addr, (void *)val, bytes,
                                   exception, &write_emultor);
}

#define CMPXCHG_TYPE(t, ptr, old, new) \
        (cmpxchg((t *)(ptr), *(t *)(old), *(t *)(new)) == *(t *)(old))

#ifdef CONFIG_X86_64
#  define CMPXCHG64(ptr, old, new) CMPXCHG_TYPE(u64, ptr, old, new)
#else
#  define CMPXCHG64(ptr, old, new) \
        (cmpxchg64((u64 *)(ptr), *(u64 *)(old), *(u64 *)(new)) == *(u64 *)(old))
#endif

static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
                                     unsigned long addr,
                                     const void *old,
                                     const void *new,
                                     unsigned int bytes,
                                     struct x86_exception *exception)
{
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
        gpa_t gpa;
        struct page *page;
        char *kaddr;
        bool exchanged;

        /* guests cmpxchg8b have to be emulated atomically */
        if (bytes > 8 || (bytes & (bytes - 1)))
                goto emul_write;

        gpa = kvm_mmu_gva_to_gpa_write(vcpu, addr, NULL);

        if (gpa == UNMAPPED_GVA ||
            (gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE)
                goto emul_write;

        if (((gpa + bytes - 1) & PAGE_MASK) != (gpa & PAGE_MASK))
                goto emul_write;

        page = kvm_vcpu_gfn_to_page(vcpu, gpa >> PAGE_SHIFT);
        if (is_error_page(page))
                goto emul_write;

        kaddr = kmap_atomic(page);
        kaddr += offset_in_page(gpa);
        switch (bytes) {
        case 1:
                exchanged = CMPXCHG_TYPE(u8, kaddr, old, new);
                break;
        case 2:
                exchanged = CMPXCHG_TYPE(u16, kaddr, old, new);
                break;
        case 4:
                exchanged = CMPXCHG_TYPE(u32, kaddr, old, new);
                break;
        case 8:
                exchanged = CMPXCHG64(kaddr, old, new);
                break;
        default:
                BUG();
        }
        kunmap_atomic(kaddr);
        kvm_release_page_dirty(page);

        if (!exchanged)
                return X86EMUL_CMPXCHG_FAILED;

        kvm_vcpu_mark_page_dirty(vcpu, gpa >> PAGE_SHIFT);
        kvm_mmu_pte_write(vcpu, gpa, new, bytes);

        return X86EMUL_CONTINUE;

emul_write:
        printk_once(KERN_WARNING "kvm: emulating exchange as write\n");

        return emulator_write_emulated(ctxt, addr, new, bytes, exception);
}

static int kernel_pio(struct kvm_vcpu *vcpu, void *pd)
{
        /* TODO: String I/O for in kernel device */
        int r;

        if (vcpu->arch.pio.in)
                r = kvm_io_bus_read(vcpu, KVM_PIO_BUS, vcpu->arch.pio.port,
                                    vcpu->arch.pio.size, pd);
        else
                r = kvm_io_bus_write(vcpu, KVM_PIO_BUS,
                                     vcpu->arch.pio.port, vcpu->arch.pio.size,
                                     pd);
        return r;
}

static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
                               unsigned short port, void *val,
                               unsigned int count, bool in)
{
        vcpu->arch.pio.port = port;
        vcpu->arch.pio.in = in;
        vcpu->arch.pio.count  = count;
        vcpu->arch.pio.size = size;

        if (!kernel_pio(vcpu, vcpu->arch.pio_data)) {
                vcpu->arch.pio.count = 0;
                return 1;
        }

        vcpu->run->exit_reason = KVM_EXIT_IO;
        vcpu->run->io.direction = in ? KVM_EXIT_IO_IN : KVM_EXIT_IO_OUT;
        vcpu->run->io.size = size;
        vcpu->run->io.data_offset = KVM_PIO_PAGE_OFFSET * PAGE_SIZE;
        vcpu->run->io.count = count;
        vcpu->run->io.port = port;

        return 0;
}

static int emulator_pio_in_emulated(struct x86_emulate_ctxt *ctxt,
                                    int size, unsigned short port, void *val,
                                    unsigned int count)
{
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
        int ret;

        if (vcpu->arch.pio.count)
                goto data_avail;

        ret = emulator_pio_in_out(vcpu, size, port, val, count, true);
        if (ret) {
data_avail:
                memcpy(val, vcpu->arch.pio_data, size * count);
                trace_kvm_pio(KVM_PIO_IN, port, size, count, vcpu->arch.pio_data);
                vcpu->arch.pio.count = 0;
                return 1;
        }

        return 0;
}

static int emulator_pio_out_emulated(struct x86_emulate_ctxt *ctxt,
                                     int size, unsigned short port,
                                     const void *val, unsigned int count)
{
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);

        memcpy(vcpu->arch.pio_data, val, size * count);
        trace_kvm_pio(KVM_PIO_OUT, port, size, count, vcpu->arch.pio_data);
        return emulator_pio_in_out(vcpu, size, port, (void *)val, count, false);
}

static unsigned long get_segment_base(struct kvm_vcpu *vcpu, int seg)
{
        return kvm_x86_ops->get_segment_base(vcpu, seg);
}

static void emulator_invlpg(struct x86_emulate_ctxt *ctxt, ulong address)
{
        kvm_mmu_invlpg(emul_to_vcpu(ctxt), address);
}

int kvm_emulate_wbinvd_noskip(struct kvm_vcpu *vcpu)
{
        if (!need_emulate_wbinvd(vcpu))
                return X86EMUL_CONTINUE;

        if (kvm_x86_ops->has_wbinvd_exit()) {
                int cpu = get_cpu();

                cpumask_set_cpu(cpu, vcpu->arch.wbinvd_dirty_mask);
                smp_call_function_many(vcpu->arch.wbinvd_dirty_mask,
                                wbinvd_ipi, NULL, 1);
                put_cpu();
                cpumask_clear(vcpu->arch.wbinvd_dirty_mask);
        } else
                wbinvd();
        return X86EMUL_CONTINUE;
}

int kvm_emulate_wbinvd(struct kvm_vcpu *vcpu)
{
        kvm_x86_ops->skip_emulated_instruction(vcpu);
        return kvm_emulate_wbinvd_noskip(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_emulate_wbinvd);



static void emulator_wbinvd(struct x86_emulate_ctxt *ctxt)
{
        kvm_emulate_wbinvd_noskip(emul_to_vcpu(ctxt));
}

static int emulator_get_dr(struct x86_emulate_ctxt *ctxt, int dr,
                           unsigned long *dest)
{
        return kvm_get_dr(emul_to_vcpu(ctxt), dr, dest);
}

static int emulator_set_dr(struct x86_emulate_ctxt *ctxt, int dr,
                           unsigned long value)
{

        return __kvm_set_dr(emul_to_vcpu(ctxt), dr, value);
}

static u64 mk_cr_64(u64 curr_cr, u32 new_val)
{
        return (curr_cr & ~((1ULL << 32) - 1)) | new_val;
}

static unsigned long emulator_get_cr(struct x86_emulate_ctxt *ctxt, int cr)
{
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
        unsigned long value;

        switch (cr) {
        case 0:
                value = kvm_read_cr0(vcpu);
                break;
        case 2:
                value = vcpu->arch.cr2;
                break;
        case 3:
                value = kvm_read_cr3(vcpu);
                break;
        case 4:
                value = kvm_read_cr4(vcpu);
                break;
        case 8:
                value = kvm_get_cr8(vcpu);
                break;
        default:
                kvm_err("%s: unexpected cr %u\n", __func__, cr);
                return 0;
        }

        return value;
}

static int emulator_set_cr(struct x86_emulate_ctxt *ctxt, int cr, ulong val)
{
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
        int res = 0;

        switch (cr) {
        case 0:
                res = kvm_set_cr0(vcpu, mk_cr_64(kvm_read_cr0(vcpu), val));
                break;
        case 2:
                vcpu->arch.cr2 = val;
                break;
        case 3:
                res = kvm_set_cr3(vcpu, val);
                break;
        case 4:
                res = kvm_set_cr4(vcpu, mk_cr_64(kvm_read_cr4(vcpu), val));
                break;
        case 8:
                res = kvm_set_cr8(vcpu, val);
                break;
        default:
                kvm_err("%s: unexpected cr %u\n", __func__, cr);
                res = -1;
        }

        return res;
}

static int emulator_get_cpl(struct x86_emulate_ctxt *ctxt)
{
        return kvm_x86_ops->get_cpl(emul_to_vcpu(ctxt));
}

static void emulator_get_gdt(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt)
{
        kvm_x86_ops->get_gdt(emul_to_vcpu(ctxt), dt);
}

static void emulator_get_idt(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt)
{
        kvm_x86_ops->get_idt(emul_to_vcpu(ctxt), dt);
}

static void emulator_set_gdt(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt)
{
        kvm_x86_ops->set_gdt(emul_to_vcpu(ctxt), dt);
}

static void emulator_set_idt(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt)
{
        kvm_x86_ops->set_idt(emul_to_vcpu(ctxt), dt);
}

static unsigned long emulator_get_cached_segment_base(
        struct x86_emulate_ctxt *ctxt, int seg)
{
        return get_segment_base(emul_to_vcpu(ctxt), seg);
}

static bool emulator_get_segment(struct x86_emulate_ctxt *ctxt, u16 *selector,
                                 struct desc_struct *desc, u32 *base3,
                                 int seg)
{
        struct kvm_segment var;

        kvm_get_segment(emul_to_vcpu(ctxt), &var, seg);
        *selector = var.selector;

        if (var.unusable) {
                memset(desc, 0, sizeof(*desc));
                return false;
        }

        if (var.g)
                var.limit >>= 12;
        set_desc_limit(desc, var.limit);
        set_desc_base(desc, (unsigned long)var.base);
#ifdef CONFIG_X86_64
        if (base3)
                *base3 = var.base >> 32;
#endif
        desc->type = var.type;
        desc->s = var.s;
        desc->dpl = var.dpl;
        desc->p = var.present;
        desc->avl = var.avl;
        desc->l = var.l;
        desc->d = var.db;
        desc->g = var.g;

        return true;
}

static void emulator_set_segment(struct x86_emulate_ctxt *ctxt, u16 selector,
                                 struct desc_struct *desc, u32 base3,
                                 int seg)
{
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
        struct kvm_segment var;

        var.selector = selector;
        var.base = get_desc_base(desc);
#ifdef CONFIG_X86_64
        var.base |= ((u64)base3) << 32;
#endif
        var.limit = get_desc_limit(desc);
        if (desc->g)
                var.limit = (var.limit << 12) | 0xfff;
        var.type = desc->type;
        var.dpl = desc->dpl;
        var.db = desc->d;
        var.s = desc->s;
        var.l = desc->l;
        var.g = desc->g;
        var.avl = desc->avl;
        var.present = desc->p;
        var.unusable = !var.present;
        var.padding = 0;

        kvm_set_segment(vcpu, &var, seg);
        return;
}

static int emulator_get_msr(struct x86_emulate_ctxt *ctxt,
                            u32 msr_index, u64 *pdata)
{
        struct msr_data msr;
        int r;

        msr.index = msr_index;
        msr.host_initiated = false;
        r = kvm_get_msr(emul_to_vcpu(ctxt), &msr);
        if (r)
                return r;

        *pdata = msr.data;
        return 0;
}

static int emulator_set_msr(struct x86_emulate_ctxt *ctxt,
                            u32 msr_index, u64 data)
{
        struct msr_data msr;

        msr.data = data;
        msr.index = msr_index;
        msr.host_initiated = false;
        return kvm_set_msr(emul_to_vcpu(ctxt), &msr);
}

static u64 emulator_get_smbase(struct x86_emulate_ctxt *ctxt)
{
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);

        return vcpu->arch.smbase;
}

static void emulator_set_smbase(struct x86_emulate_ctxt *ctxt, u64 smbase)
{
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);

        vcpu->arch.smbase = smbase;
}

static int emulator_check_pmc(struct x86_emulate_ctxt *ctxt,
                              u32 pmc)
{
        return kvm_pmu_is_valid_msr_idx(emul_to_vcpu(ctxt), pmc);
}

static int emulator_read_pmc(struct x86_emulate_ctxt *ctxt,
                             u32 pmc, u64 *pdata)
{
        return kvm_pmu_rdpmc(emul_to_vcpu(ctxt), pmc, pdata);
}

static void emulator_halt(struct x86_emulate_ctxt *ctxt)
{
        emul_to_vcpu(ctxt)->arch.halt_request = 1;
}

static void emulator_get_fpu(struct x86_emulate_ctxt *ctxt)
{
        preempt_disable();
        kvm_load_guest_fpu(emul_to_vcpu(ctxt));
        /*
         * CR0.TS may reference the host fpu state, not the guest fpu state,
         * so it may be clear at this point.
         */
        clts();
}

static void emulator_put_fpu(struct x86_emulate_ctxt *ctxt)
{
        preempt_enable();
}

static int emulator_intercept(struct x86_emulate_ctxt *ctxt,
                              struct x86_instruction_info *info,
                              enum x86_intercept_stage stage)
{
        return kvm_x86_ops->check_intercept(emul_to_vcpu(ctxt), info, stage);
}

static void emulator_get_cpuid(struct x86_emulate_ctxt *ctxt,
                               u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
{
        kvm_cpuid(emul_to_vcpu(ctxt), eax, ebx, ecx, edx);
}

static ulong emulator_read_gpr(struct x86_emulate_ctxt *ctxt, unsigned reg)
{
        return kvm_register_read(emul_to_vcpu(ctxt), reg);
}

static void emulator_write_gpr(struct x86_emulate_ctxt *ctxt, unsigned reg, ulong val)
{
        kvm_register_write(emul_to_vcpu(ctxt), reg, val);
}

static void emulator_set_nmi_mask(struct x86_emulate_ctxt *ctxt, bool masked)
{
        kvm_x86_ops->set_nmi_mask(emul_to_vcpu(ctxt), masked);
}

static const struct x86_emulate_ops emulate_ops = {
        .read_gpr            = emulator_read_gpr,
        .write_gpr           = emulator_write_gpr,
        .read_std            = kvm_read_guest_virt_system,
        .write_std           = kvm_write_guest_virt_system,
        .fetch               = kvm_fetch_guest_virt,
        .read_emulated       = emulator_read_emulated,
        .write_emulated      = emulator_write_emulated,
        .cmpxchg_emulated    = emulator_cmpxchg_emulated,
        .invlpg              = emulator_invlpg,
        .pio_in_emulated     = emulator_pio_in_emulated,
        .pio_out_emulated    = emulator_pio_out_emulated,
        .get_segment         = emulator_get_segment,
        .set_segment         = emulator_set_segment,
        .get_cached_segment_base = emulator_get_cached_segment_base,
        .get_gdt             = emulator_get_gdt,
        .get_idt             = emulator_get_idt,
        .set_gdt             = emulator_set_gdt,
        .set_idt             = emulator_set_idt,
        .get_cr              = emulator_get_cr,
        .set_cr              = emulator_set_cr,
        .cpl                 = emulator_get_cpl,
        .get_dr              = emulator_get_dr,
        .set_dr              = emulator_set_dr,
        .get_smbase          = emulator_get_smbase,
        .set_smbase          = emulator_set_smbase,
        .set_msr             = emulator_set_msr,
        .get_msr             = emulator_get_msr,
        .check_pmc           = emulator_check_pmc,
        .read_pmc            = emulator_read_pmc,
        .halt                = emulator_halt,
        .wbinvd              = emulator_wbinvd,
        .fix_hypercall       = emulator_fix_hypercall,
        .get_fpu             = emulator_get_fpu,
        .put_fpu             = emulator_put_fpu,
        .intercept           = emulator_intercept,
        .get_cpuid           = emulator_get_cpuid,
        .set_nmi_mask        = emulator_set_nmi_mask,
};

static void toggle_interruptibility(struct kvm_vcpu *vcpu, u32 mask)
{
        u32 int_shadow = kvm_x86_ops->get_interrupt_shadow(vcpu);
        /*
         * an sti; sti; sequence only disable interrupts for the first
         * instruction. So, if the last instruction, be it emulated or
         * not, left the system with the INT_STI flag enabled, it
         * means that the last instruction is an sti. We should not
         * leave the flag on in this case. The same goes for mov ss
         */
        if (int_shadow & mask)
                mask = 0;
        if (unlikely(int_shadow || mask)) {
                kvm_x86_ops->set_interrupt_shadow(vcpu, mask);
                if (!mask)
                        kvm_make_request(KVM_REQ_EVENT, vcpu);
        }
}

static bool inject_emulated_exception(struct kvm_vcpu *vcpu)
{
        struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
        if (ctxt->exception.vector == PF_VECTOR)
                return kvm_propagate_fault(vcpu, &ctxt->exception);

        if (ctxt->exception.error_code_valid)
                kvm_queue_exception_e(vcpu, ctxt->exception.vector,
                                      ctxt->exception.error_code);
        else
                kvm_queue_exception(vcpu, ctxt->exception.vector);
        return false;
}

static void init_emulate_ctxt(struct kvm_vcpu *vcpu)
{
        struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
        int cs_db, cs_l;

        kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);

        ctxt->eflags = kvm_get_rflags(vcpu);
        ctxt->eip = kvm_rip_read(vcpu);
        ctxt->mode = (!is_protmode(vcpu))               ? X86EMUL_MODE_REAL :
                     (ctxt->eflags & X86_EFLAGS_VM)     ? X86EMUL_MODE_VM86 :
                     (cs_l && is_long_mode(vcpu))       ? X86EMUL_MODE_PROT64 :
                     cs_db                              ? X86EMUL_MODE_PROT32 :
                                                          X86EMUL_MODE_PROT16;
        BUILD_BUG_ON(HF_GUEST_MASK != X86EMUL_GUEST_MASK);
        BUILD_BUG_ON(HF_SMM_MASK != X86EMUL_SMM_MASK);
        BUILD_BUG_ON(HF_SMM_INSIDE_NMI_MASK != X86EMUL_SMM_INSIDE_NMI_MASK);
        ctxt->emul_flags = vcpu->arch.hflags;

        init_decode_cache(ctxt);
        vcpu->arch.emulate_regs_need_sync_from_vcpu = false;
}

int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip)
{
        struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
        int ret;

        init_emulate_ctxt(vcpu);

        ctxt->op_bytes = 2;
        ctxt->ad_bytes = 2;
        ctxt->_eip = ctxt->eip + inc_eip;
        ret = emulate_int_real(ctxt, irq);

        if (ret != X86EMUL_CONTINUE)
                return EMULATE_FAIL;

        ctxt->eip = ctxt->_eip;
        kvm_rip_write(vcpu, ctxt->eip);
        kvm_set_rflags(vcpu, ctxt->eflags);

        if (irq == NMI_VECTOR)
                vcpu->arch.nmi_pending = 0;
        else
                vcpu->arch.interrupt.pending = false;

        return EMULATE_DONE;
}
EXPORT_SYMBOL_GPL(kvm_inject_realmode_interrupt);

static int handle_emulation_failure(struct kvm_vcpu *vcpu)
{
        int r = EMULATE_DONE;

        ++vcpu->stat.insn_emulation_fail;
        trace_kvm_emulate_insn_failed(vcpu);
        if (!is_guest_mode(vcpu) && kvm_x86_ops->get_cpl(vcpu) == 0) {
                vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
                vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
                vcpu->run->internal.ndata = 0;
                r = EMULATE_FAIL;
        }
        kvm_queue_exception(vcpu, UD_VECTOR);

        return r;
}

static bool reexecute_instruction(struct kvm_vcpu *vcpu, gva_t cr2,
                                  bool write_fault_to_shadow_pgtable,
                                  int emulation_type)
{
        gpa_t gpa = cr2;
        pfn_t pfn;

        if (emulation_type & EMULTYPE_NO_REEXECUTE)
                return false;

        if (!vcpu->arch.mmu.direct_map) {
                /*
                 * Write permission should be allowed since only
                 * write access need to be emulated.
                 */
                gpa = kvm_mmu_gva_to_gpa_write(vcpu, cr2, NULL);

                /*
                 * If the mapping is invalid in guest, let cpu retry
                 * it to generate fault.
                 */
                if (gpa == UNMAPPED_GVA)
                        return true;
        }

        /*
         * Do not retry the unhandleable instruction if it faults on the
         * readonly host memory, otherwise it will goto a infinite loop:
         * retry instruction -> write #PF -> emulation fail -> retry
         * instruction -> ...
         */
        pfn = gfn_to_pfn(vcpu->kvm, gpa_to_gfn(gpa));

        /*
         * If the instruction failed on the error pfn, it can not be fixed,
         * report the error to userspace.
         */
        if (is_error_noslot_pfn(pfn))
                return false;

        kvm_release_pfn_clean(pfn);

        /* The instructions are well-emulated on direct mmu. */
        if (vcpu->arch.mmu.direct_map) {
                unsigned int indirect_shadow_pages;

                spin_lock(&vcpu->kvm->mmu_lock);
                indirect_shadow_pages = vcpu->kvm->arch.indirect_shadow_pages;
                spin_unlock(&vcpu->kvm->mmu_lock);

                if (indirect_shadow_pages)
                        kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(gpa));

                return true;
        }

        /*
         * if emulation was due to access to shadowed page table
         * and it failed try to unshadow page and re-enter the
         * guest to let CPU execute the instruction.
         */
        kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(gpa));

        /*
         * If the access faults on its page table, it can not
         * be fixed by unprotecting shadow page and it should
         * be reported to userspace.
         */
        return !write_fault_to_shadow_pgtable;
}

static bool retry_instruction(struct x86_emulate_ctxt *ctxt,
                              unsigned long cr2,  int emulation_type)
{
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
        unsigned long last_retry_eip, last_retry_addr, gpa = cr2;

        last_retry_eip = vcpu->arch.last_retry_eip;
        last_retry_addr = vcpu->arch.last_retry_addr;

        /*
         * If the emulation is caused by #PF and it is non-page_table
         * writing instruction, it means the VM-EXIT is caused by shadow
         * page protected, we can zap the shadow page and retry this
         * instruction directly.
         *
         * Note: if the guest uses a non-page-table modifying instruction
         * on the PDE that points to the instruction, then we will unmap
         * the instruction and go to an infinite loop. So, we cache the
         * last retried eip and the last fault address, if we meet the eip
         * and the address again, we can break out of the potential infinite
         * loop.
         */
        vcpu->arch.last_retry_eip = vcpu->arch.last_retry_addr = 0;

        if (!(emulation_type & EMULTYPE_RETRY))
                return false;

        if (x86_page_table_writing_insn(ctxt))
                return false;

        if (ctxt->eip == last_retry_eip && last_retry_addr == cr2)
                return false;

        vcpu->arch.last_retry_eip = ctxt->eip;
        vcpu->arch.last_retry_addr = cr2;

        if (!vcpu->arch.mmu.direct_map)
                gpa = kvm_mmu_gva_to_gpa_write(vcpu, cr2, NULL);

        kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(gpa));

        return true;
}

static int complete_emulated_mmio(struct kvm_vcpu *vcpu);
static int complete_emulated_pio(struct kvm_vcpu *vcpu);

static void kvm_smm_changed(struct kvm_vcpu *vcpu)
{
        if (!(vcpu->arch.hflags & HF_SMM_MASK)) {
                /* This is a good place to trace that we are exiting SMM.  */
                trace_kvm_enter_smm(vcpu->vcpu_id, vcpu->arch.smbase, false);

                if (unlikely(vcpu->arch.smi_pending)) {
                        kvm_make_request(KVM_REQ_SMI, vcpu);
                        vcpu->arch.smi_pending = 0;
                } else {
                        /* Process a latched INIT, if any.  */
                        kvm_make_request(KVM_REQ_EVENT, vcpu);
                }
        }

        kvm_mmu_reset_context(vcpu);
}

static void kvm_set_hflags(struct kvm_vcpu *vcpu, unsigned emul_flags)
{
        unsigned changed = vcpu->arch.hflags ^ emul_flags;

        vcpu->arch.hflags = emul_flags;

        if (changed & HF_SMM_MASK)
                kvm_smm_changed(vcpu);
}

static int kvm_vcpu_check_hw_bp(unsigned long addr, u32 type, u32 dr7,
                                unsigned long *db)
{
        u32 dr6 = 0;
        int i;
        u32 enable, rwlen;

        enable = dr7;
        rwlen = dr7 >> 16;
        for (i = 0; i < 4; i++, enable >>= 2, rwlen >>= 4)
                if ((enable & 3) && (rwlen & 15) == type && db[i] == addr)
                        dr6 |= (1 << i);
        return dr6;
}

static void kvm_vcpu_check_singlestep(struct kvm_vcpu *vcpu, unsigned long rflags, int *r)
{
        struct kvm_run *kvm_run = vcpu->run;

        /*
         * rflags is the old, "raw" value of the flags.  The new value has
         * not been saved yet.
         *
         * This is correct even for TF set by the guest, because "the
         * processor will not generate this exception after the instruction
         * that sets the TF flag".
         */
        if (unlikely(rflags & X86_EFLAGS_TF)) {
                if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {
                        kvm_run->debug.arch.dr6 = DR6_BS | DR6_FIXED_1 |
                                                  DR6_RTM;
                        kvm_run->debug.arch.pc = vcpu->arch.singlestep_rip;
                        kvm_run->debug.arch.exception = DB_VECTOR;
                        kvm_run->exit_reason = KVM_EXIT_DEBUG;
                        *r = EMULATE_USER_EXIT;
                } else {
                        vcpu->arch.emulate_ctxt.eflags &= ~X86_EFLAGS_TF;
                        /*
                         * "Certain debug exceptions may clear bit 0-3.  The
                         * remaining contents of the DR6 register are never
                         * cleared by the processor".
                         */
                        vcpu->arch.dr6 &= ~15;
                        vcpu->arch.dr6 |= DR6_BS | DR6_RTM;
                        kvm_queue_exception(vcpu, DB_VECTOR);
                }
        }
}

static bool kvm_vcpu_check_breakpoint(struct kvm_vcpu *vcpu, int *r)
{
        if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) &&
            (vcpu->arch.guest_debug_dr7 & DR7_BP_EN_MASK)) {
                struct kvm_run *kvm_run = vcpu->run;
                unsigned long eip = kvm_get_linear_rip(vcpu);
                u32 dr6 = kvm_vcpu_check_hw_bp(eip, 0,
                                           vcpu->arch.guest_debug_dr7,
                                           vcpu->arch.eff_db);

                if (dr6 != 0) {
                        kvm_run->debug.arch.dr6 = dr6 | DR6_FIXED_1 | DR6_RTM;
                        kvm_run->debug.arch.pc = eip;
                        kvm_run->debug.arch.exception = DB_VECTOR;
                        kvm_run->exit_reason = KVM_EXIT_DEBUG;
                        *r = EMULATE_USER_EXIT;
                        return true;
                }
        }

        if (unlikely(vcpu->arch.dr7 & DR7_BP_EN_MASK) &&
            !(kvm_get_rflags(vcpu) & X86_EFLAGS_RF)) {
                unsigned long eip = kvm_get_linear_rip(vcpu);
                u32 dr6 = kvm_vcpu_check_hw_bp(eip, 0,
                                           vcpu->arch.dr7,
                                           vcpu->arch.db);

                if (dr6 != 0) {
                        vcpu->arch.dr6 &= ~15;
                        vcpu->arch.dr6 |= dr6 | DR6_RTM;
                        kvm_queue_exception(vcpu, DB_VECTOR);
                        *r = EMULATE_DONE;
                        return true;
                }
        }

        return false;
}

int x86_emulate_instruction(struct kvm_vcpu *vcpu,
                            unsigned long cr2,
                            int emulation_type,
                            void *insn,
                            int insn_len)
{
        int r;
        struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
        bool writeback = true;
        bool write_fault_to_spt = vcpu->arch.write_fault_to_shadow_pgtable;

        /*
         * Clear write_fault_to_shadow_pgtable here to ensure it is
         * never reused.
         */
        vcpu->arch.write_fault_to_shadow_pgtable = false;
        kvm_clear_exception_queue(vcpu);

        if (!(emulation_type & EMULTYPE_NO_DECODE)) {
                init_emulate_ctxt(vcpu);

                /*
                 * We will reenter on the same instruction since
                 * we do not set complete_userspace_io.  This does not
                 * handle watchpoints yet, those would be handled in
                 * the emulate_ops.
                 */
                if (kvm_vcpu_check_breakpoint(vcpu, &r))
                        return r;

                ctxt->interruptibility = 0;
                ctxt->have_exception = false;
                ctxt->exception.vector = -1;
                ctxt->perm_ok = false;

                ctxt->ud = emulation_type & EMULTYPE_TRAP_UD;

                r = x86_decode_insn(ctxt, insn, insn_len);

                trace_kvm_emulate_insn_start(vcpu);
                ++vcpu->stat.insn_emulation;
                if (r != EMULATION_OK)  {
                        if (emulation_type & EMULTYPE_TRAP_UD)
                                return EMULATE_FAIL;
                        if (reexecute_instruction(vcpu, cr2, write_fault_to_spt,
                                                emulation_type))
                                return EMULATE_DONE;
                        if (emulation_type & EMULTYPE_SKIP)
                                return EMULATE_FAIL;
                        return handle_emulation_failure(vcpu);
                }
        }

        if (emulation_type & EMULTYPE_SKIP) {
                kvm_rip_write(vcpu, ctxt->_eip);
                if (ctxt->eflags & X86_EFLAGS_RF)
                        kvm_set_rflags(vcpu, ctxt->eflags & ~X86_EFLAGS_RF);
                return EMULATE_DONE;
        }

        if (retry_instruction(ctxt, cr2, emulation_type))
                return EMULATE_DONE;

        /* this is needed for vmware backdoor interface to work since it
           changes registers values  during IO operation */
        if (vcpu->arch.emulate_regs_need_sync_from_vcpu) {
                vcpu->arch.emulate_regs_need_sync_from_vcpu = false;
                emulator_invalidate_register_cache(ctxt);
        }

restart:
        r = x86_emulate_insn(ctxt);

        if (r == EMULATION_INTERCEPTED)
                return EMULATE_DONE;

        if (r == EMULATION_FAILED) {
                if (reexecute_instruction(vcpu, cr2, write_fault_to_spt,
                                        emulation_type))
                        return EMULATE_DONE;

                return handle_emulation_failure(vcpu);
        }

        if (ctxt->have_exception) {
                r = EMULATE_DONE;
                if (inject_emulated_exception(vcpu))
                        return r;
        } else if (vcpu->arch.pio.count) {
                if (!vcpu->arch.pio.in) {
                        /* FIXME: return into emulator if single-stepping.  */
                        vcpu->arch.pio.count = 0;
                } else {
                        writeback = false;
                        vcpu->arch.complete_userspace_io = complete_emulated_pio;
                }
                r = EMULATE_USER_EXIT;
        } else if (vcpu->mmio_needed) {
                if (!vcpu->mmio_is_write)
                        writeback = false;
                r = EMULATE_USER_EXIT;
                vcpu->arch.complete_userspace_io = complete_emulated_mmio;
        } else if (r == EMULATION_RESTART)
                goto restart;
        else
                r = EMULATE_DONE;

        if (writeback) {
                unsigned long rflags = kvm_x86_ops->get_rflags(vcpu);
                toggle_interruptibility(vcpu, ctxt->interruptibility);
                vcpu->arch.emulate_regs_need_sync_to_vcpu = false;
                if (vcpu->arch.hflags != ctxt->emul_flags)
                        kvm_set_hflags(vcpu, ctxt->emul_flags);
                kvm_rip_write(vcpu, ctxt->eip);
                if (r == EMULATE_DONE)
                        kvm_vcpu_check_singlestep(vcpu, rflags, &r);
                if (!ctxt->have_exception ||
                    exception_type(ctxt->exception.vector) == EXCPT_TRAP)
                        __kvm_set_rflags(vcpu, ctxt->eflags);

                /*
                 * For STI, interrupts are shadowed; so KVM_REQ_EVENT will
                 * do nothing, and it will be requested again as soon as
                 * the shadow expires.  But we still need to check here,
                 * because POPF has no interrupt shadow.
                 */
                if (unlikely((ctxt->eflags & ~rflags) & X86_EFLAGS_IF))
                        kvm_make_request(KVM_REQ_EVENT, vcpu);
        } else
                vcpu->arch.emulate_regs_need_sync_to_vcpu = true;

        return r;
}
EXPORT_SYMBOL_GPL(x86_emulate_instruction);

int kvm_fast_pio_out(struct kvm_vcpu *vcpu, int size, unsigned short port)
{
        unsigned long val = kvm_register_read(vcpu, VCPU_REGS_RAX);
        int ret = emulator_pio_out_emulated(&vcpu->arch.emulate_ctxt,
                                            size, port, &val, 1);
        /* do not return to emulator after return from userspace */
        vcpu->arch.pio.count = 0;
        return ret;
}
EXPORT_SYMBOL_GPL(kvm_fast_pio_out);

static void tsc_bad(void *info)
{
        __this_cpu_write(cpu_tsc_khz, 0);
}

static void tsc_khz_changed(void *data)
{
        struct cpufreq_freqs *freq = data;
        unsigned long khz = 0;

        if (data)
                khz = freq->new;
        else if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
                khz = cpufreq_quick_get(raw_smp_processor_id());
        if (!khz)
                khz = tsc_khz;
        __this_cpu_write(cpu_tsc_khz, khz);
}

static int kvmclock_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
                                     void *data)
{
        struct cpufreq_freqs *freq = data;
        struct kvm *kvm;
        struct kvm_vcpu *vcpu;
        int i, send_ipi = 0;

        /*
         * We allow guests to temporarily run on slowing clocks,
         * provided we notify them after, or to run on accelerating
         * clocks, provided we notify them before.  Thus time never
         * goes backwards.
         *
         * However, we have a problem.  We can't atomically update
         * the frequency of a given CPU from this function; it is
         * merely a notifier, which can be called from any CPU.
         * Changing the TSC frequency at arbitrary points in time
         * requires a recomputation of local variables related to
         * the TSC for each VCPU.  We must flag these local variables
         * to be updated and be sure the update takes place with the
         * new frequency before any guests proceed.
         *
         * Unfortunately, the combination of hotplug CPU and frequency
         * change creates an intractable locking scenario; the order
         * of when these callouts happen is undefined with respect to
         * CPU hotplug, and they can race with each other.  As such,
         * merely setting per_cpu(cpu_tsc_khz) = X during a hotadd is
         * undefined; you can actually have a CPU frequency change take
         * place in between the computation of X and the setting of the
         * variable.  To protect against this problem, all updates of
         * the per_cpu tsc_khz variable are done in an interrupt
         * protected IPI, and all callers wishing to update the value
         * must wait for a synchronous IPI to complete (which is trivial
         * if the caller is on the CPU already).  This establishes the
         * necessary total order on variable updates.
         *
         * Note that because a guest time update may take place
         * anytime after the setting of the VCPU's request bit, the
         * correct TSC value must be set before the request.  However,
         * to ensure the update actually makes it to any guest which
         * starts running in hardware virtualization between the set
         * and the acquisition of the spinlock, we must also ping the
         * CPU after setting the request bit.
         *
         */

        if (val == CPUFREQ_PRECHANGE && freq->old > freq->new)
                return 0;
        if (val == CPUFREQ_POSTCHANGE && freq->old < freq->new)
                return 0;

        smp_call_function_single(freq->cpu, tsc_khz_changed, freq, 1);

        spin_lock(&kvm_lock);
        list_for_each_entry(kvm, &vm_list, vm_list) {
                kvm_for_each_vcpu(i, vcpu, kvm) {
                        if (vcpu->cpu != freq->cpu)
                                continue;
                        kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
                        if (vcpu->cpu != smp_processor_id())
                                send_ipi = 1;
                }
        }
        spin_unlock(&kvm_lock);

        if (freq->old < freq->new && send_ipi) {
                /*
                 * We upscale the frequency.  Must make the guest
                 * doesn't see old kvmclock values while running with
                 * the new frequency, otherwise we risk the guest sees
                 * time go backwards.
                 *
                 * In case we update the frequency for another cpu
                 * (which might be in guest context) send an interrupt
                 * to kick the cpu out of guest context.  Next time
                 * guest context is entered kvmclock will be updated,
                 * so the guest will not see stale values.
                 */
                smp_call_function_single(freq->cpu, tsc_khz_changed, freq, 1);
        }
        return 0;
}

static struct notifier_block kvmclock_cpufreq_notifier_block = {
        .notifier_call  = kvmclock_cpufreq_notifier
};

static int kvmclock_cpu_notifier(struct notifier_block *nfb,
                                        unsigned long action, void *hcpu)
{
        unsigned int cpu = (unsigned long)hcpu;

        switch (action) {
                case CPU_ONLINE:
                case CPU_DOWN_FAILED:
                        smp_call_function_single(cpu, tsc_khz_changed, NULL, 1);
                        break;
                case CPU_DOWN_PREPARE:
                        smp_call_function_single(cpu, tsc_bad, NULL, 1);
                        break;
        }
        return NOTIFY_OK;
}

static struct notifier_block kvmclock_cpu_notifier_block = {
        .notifier_call  = kvmclock_cpu_notifier,
        .priority = -INT_MAX
};

static void kvm_timer_init(void)
{
        int cpu;

        max_tsc_khz = tsc_khz;

        cpu_notifier_register_begin();
        if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) {
#ifdef CONFIG_CPU_FREQ
                struct cpufreq_policy policy;
                memset(&policy, 0, sizeof(policy));
                cpu = get_cpu();
                cpufreq_get_policy(&policy, cpu);
                if (policy.cpuinfo.max_freq)
                        max_tsc_khz = policy.cpuinfo.max_freq;
                put_cpu();
#endif
                cpufreq_register_notifier(&kvmclock_cpufreq_notifier_block,
                                          CPUFREQ_TRANSITION_NOTIFIER);
        }
        pr_debug("kvm: max_tsc_khz = %ld\n", max_tsc_khz);
        for_each_online_cpu(cpu)
                smp_call_function_single(cpu, tsc_khz_changed, NULL, 1);

        __register_hotcpu_notifier(&kvmclock_cpu_notifier_block);
        cpu_notifier_register_done();

}

static DEFINE_PER_CPU(struct kvm_vcpu *, current_vcpu);

int kvm_is_in_guest(void)
{
        return __this_cpu_read(current_vcpu) != NULL;
}

static int kvm_is_user_mode(void)
{
        int user_mode = 3;

        if (__this_cpu_read(current_vcpu))
                user_mode = kvm_x86_ops->get_cpl(__this_cpu_read(current_vcpu));

        return user_mode != 0;
}

static unsigned long kvm_get_guest_ip(void)
{
        unsigned long ip = 0;

        if (__this_cpu_read(current_vcpu))
                ip = kvm_rip_read(__this_cpu_read(current_vcpu));

        return ip;
}

static struct perf_guest_info_callbacks kvm_guest_cbs = {
        .is_in_guest            = kvm_is_in_guest,
        .is_user_mode           = kvm_is_user_mode,
        .get_guest_ip           = kvm_get_guest_ip,
};

void kvm_before_handle_nmi(struct kvm_vcpu *vcpu)
{
        __this_cpu_write(current_vcpu, vcpu);
}
EXPORT_SYMBOL_GPL(kvm_before_handle_nmi);

void kvm_after_handle_nmi(struct kvm_vcpu *vcpu)
{
        __this_cpu_write(current_vcpu, NULL);
}
EXPORT_SYMBOL_GPL(kvm_after_handle_nmi);

static void kvm_set_mmio_spte_mask(void)
{
        u64 mask;
        int maxphyaddr = boot_cpu_data.x86_phys_bits;

        /*
         * Set the reserved bits and the present bit of an paging-structure
         * entry to generate page fault with PFER.RSV = 1.
         */
         /* Mask the reserved physical address bits. */
        mask = rsvd_bits(maxphyaddr, 51);

        /* Bit 62 is always reserved for 32bit host. */
        mask |= 0x3ull << 62;

        /* Set the present bit. */
        mask |= 1ull;

#ifdef CONFIG_X86_64
        /*
         * If reserved bit is not supported, clear the present bit to disable
         * mmio page fault.
         */
        if (maxphyaddr == 52)
                mask &= ~1ull;
#endif

        kvm_mmu_set_mmio_spte_mask(mask);
}

#ifdef CONFIG_X86_64
static void pvclock_gtod_update_fn(struct work_struct *work)
{
        struct kvm *kvm;

        struct kvm_vcpu *vcpu;
        int i;

        spin_lock(&kvm_lock);
        list_for_each_entry(kvm, &vm_list, vm_list)
                kvm_for_each_vcpu(i, vcpu, kvm)
                        kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);
        atomic_set(&kvm_guest_has_master_clock, 0);
        spin_unlock(&kvm_lock);
}

static DECLARE_WORK(pvclock_gtod_work, pvclock_gtod_update_fn);

/*
 * Notification about pvclock gtod data update.
 */
static int pvclock_gtod_notify(struct notifier_block *nb, unsigned long unused,
                               void *priv)
{
        struct pvclock_gtod_data *gtod = &pvclock_gtod_data;
        struct timekeeper *tk = priv;

        update_pvclock_gtod(tk);

        /* disable master clock if host does not trust, or does not
         * use, TSC clocksource
         */
        if (gtod->clock.vclock_mode != VCLOCK_TSC &&
            atomic_read(&kvm_guest_has_master_clock) != 0)
                queue_work(system_long_wq, &pvclock_gtod_work);

        return 0;
}

static struct notifier_block pvclock_gtod_notifier = {
        .notifier_call = pvclock_gtod_notify,
};
#endif

int kvm_arch_init(void *opaque)
{
        int r;
        struct kvm_x86_ops *ops = opaque;

        if (kvm_x86_ops) {
                printk(KERN_ERR "kvm: already loaded the other module\n");
                r = -EEXIST;
                goto out;
        }

        if (!ops->cpu_has_kvm_support()) {
                printk(KERN_ERR "kvm: no hardware support\n");
                r = -EOPNOTSUPP;
                goto out;
        }
        if (ops->disabled_by_bios()) {
                printk(KERN_ERR "kvm: disabled by bios\n");
                r = -EOPNOTSUPP;
                goto out;
        }

        r = -ENOMEM;
        shared_msrs = alloc_percpu(struct kvm_shared_msrs);
        if (!shared_msrs) {
                printk(KERN_ERR "kvm: failed to allocate percpu kvm_shared_msrs\n");
                goto out;
        }

        r = kvm_mmu_module_init();
        if (r)
                goto out_free_percpu;

        kvm_set_mmio_spte_mask();

        kvm_x86_ops = ops;

        kvm_mmu_set_mask_ptes(PT_USER_MASK, PT_ACCESSED_MASK,
                        PT_DIRTY_MASK, PT64_NX_MASK, 0);

        kvm_timer_init();

        perf_register_guest_info_callbacks(&kvm_guest_cbs);

        if (cpu_has_xsave)
                host_xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);

        kvm_lapic_init();
#ifdef CONFIG_X86_64
        pvclock_gtod_register_notifier(&pvclock_gtod_notifier);
#endif

        return 0;

out_free_percpu:
        free_percpu(shared_msrs);
out:
        return r;
}

void kvm_arch_exit(void)
{
        perf_unregister_guest_info_callbacks(&kvm_guest_cbs);

        if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
                cpufreq_unregister_notifier(&kvmclock_cpufreq_notifier_block,
                                            CPUFREQ_TRANSITION_NOTIFIER);
        unregister_hotcpu_notifier(&kvmclock_cpu_notifier_block);
#ifdef CONFIG_X86_64
        pvclock_gtod_unregister_notifier(&pvclock_gtod_notifier);
#endif
        kvm_x86_ops = NULL;
        kvm_mmu_module_exit();
        free_percpu(shared_msrs);
}

int kvm_vcpu_halt(struct kvm_vcpu *vcpu)
{
        ++vcpu->stat.halt_exits;
        if (irqchip_in_kernel(vcpu->kvm)) {
                vcpu->arch.mp_state = KVM_MP_STATE_HALTED;
                return 1;
        } else {
                vcpu->run->exit_reason = KVM_EXIT_HLT;
                return 0;
        }
}
EXPORT_SYMBOL_GPL(kvm_vcpu_halt);

int kvm_emulate_halt(struct kvm_vcpu *vcpu)
{
        kvm_x86_ops->skip_emulated_instruction(vcpu);
        return kvm_vcpu_halt(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_emulate_halt);

/*
 * kvm_pv_kick_cpu_op:  Kick a vcpu.
 *
 * @apicid - apicid of vcpu to be kicked.
 */
static void kvm_pv_kick_cpu_op(struct kvm *kvm, unsigned long flags, int apicid)
{
        struct kvm_lapic_irq lapic_irq;

        lapic_irq.shorthand = 0;
        lapic_irq.dest_mode = 0;
        lapic_irq.dest_id = apicid;
        lapic_irq.msi_redir_hint = false;

        lapic_irq.delivery_mode = APIC_DM_REMRD;
        kvm_irq_delivery_to_apic(kvm, NULL, &lapic_irq, NULL);
}

int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
{
        unsigned long nr, a0, a1, a2, a3, ret;
        int op_64_bit, r = 1;

        kvm_x86_ops->skip_emulated_instruction(vcpu);

        if (kvm_hv_hypercall_enabled(vcpu->kvm))
                return kvm_hv_hypercall(vcpu);

        nr = kvm_register_read(vcpu, VCPU_REGS_RAX);
        a0 = kvm_register_read(vcpu, VCPU_REGS_RBX);
        a1 = kvm_register_read(vcpu, VCPU_REGS_RCX);
        a2 = kvm_register_read(vcpu, VCPU_REGS_RDX);
        a3 = kvm_register_read(vcpu, VCPU_REGS_RSI);

        trace_kvm_hypercall(nr, a0, a1, a2, a3);

        op_64_bit = is_64_bit_mode(vcpu);
        if (!op_64_bit) {
                nr &= 0xFFFFFFFF;
                a0 &= 0xFFFFFFFF;
                a1 &= 0xFFFFFFFF;
                a2 &= 0xFFFFFFFF;
                a3 &= 0xFFFFFFFF;
        }

        if (kvm_x86_ops->get_cpl(vcpu) != 0) {
                ret = -KVM_EPERM;
                goto out;
        }

        switch (nr) {
        case KVM_HC_VAPIC_POLL_IRQ:
                ret = 0;
                break;
        case KVM_HC_KICK_CPU:
                kvm_pv_kick_cpu_op(vcpu->kvm, a0, a1);
                ret = 0;
                break;
        default:
                ret = -KVM_ENOSYS;
                break;
        }
out:
        if (!op_64_bit)
                ret = (u32)ret;
        kvm_register_write(vcpu, VCPU_REGS_RAX, ret);
        ++vcpu->stat.hypercalls;
        return r;
}
EXPORT_SYMBOL_GPL(kvm_emulate_hypercall);

static int emulator_fix_hypercall(struct x86_emulate_ctxt *ctxt)
{
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
        char instruction[3];
        unsigned long rip = kvm_rip_read(vcpu);

        kvm_x86_ops->patch_hypercall(vcpu, instruction);

        return emulator_write_emulated(ctxt, rip, instruction, 3, NULL);
}

/*
 * Check if userspace requested an interrupt window, and that the
 * interrupt window is open.
 *
 * No need to exit to userspace if we already have an interrupt queued.
 */
static int dm_request_for_irq_injection(struct kvm_vcpu *vcpu)
{
        return (!irqchip_in_kernel(vcpu->kvm) && !kvm_cpu_has_interrupt(vcpu) &&
                vcpu->run->request_interrupt_window &&
                kvm_arch_interrupt_allowed(vcpu));
}

static void post_kvm_run_save(struct kvm_vcpu *vcpu)
{
        struct kvm_run *kvm_run = vcpu->run;

        kvm_run->if_flag = (kvm_get_rflags(vcpu) & X86_EFLAGS_IF) != 0;
        kvm_run->flags = is_smm(vcpu) ? KVM_RUN_X86_SMM : 0;
        kvm_run->cr8 = kvm_get_cr8(vcpu);
        kvm_run->apic_base = kvm_get_apic_base(vcpu);
        if (irqchip_in_kernel(vcpu->kvm))
                kvm_run->ready_for_interrupt_injection = 1;
        else
                kvm_run->ready_for_interrupt_injection =
                        kvm_arch_interrupt_allowed(vcpu) &&
                        !kvm_cpu_has_interrupt(vcpu) &&
                        !kvm_event_needs_reinjection(vcpu);
}

static void update_cr8_intercept(struct kvm_vcpu *vcpu)
{
        int max_irr, tpr;

        if (!kvm_x86_ops->update_cr8_intercept)
                return;

        if (!vcpu->arch.apic)
                return;

        if (!vcpu->arch.apic->vapic_addr)
                max_irr = kvm_lapic_find_highest_irr(vcpu);
        else
                max_irr = -1;

        if (max_irr != -1)
                max_irr >>= 4;

        tpr = kvm_lapic_get_cr8(vcpu);

        kvm_x86_ops->update_cr8_intercept(vcpu, tpr, max_irr);
}

static int inject_pending_event(struct kvm_vcpu *vcpu, bool req_int_win)
{
        int r;

        /* try to reinject previous events if any */
        if (vcpu->arch.exception.pending) {
                trace_kvm_inj_exception(vcpu->arch.exception.nr,
                                        vcpu->arch.exception.has_error_code,
                                        vcpu->arch.exception.error_code);

                if (exception_type(vcpu->arch.exception.nr) == EXCPT_FAULT)
                        __kvm_set_rflags(vcpu, kvm_get_rflags(vcpu) |
                                             X86_EFLAGS_RF);

                if (vcpu->arch.exception.nr == DB_VECTOR &&
                    (vcpu->arch.dr7 & DR7_GD)) {
                        vcpu->arch.dr7 &= ~DR7_GD;
                        kvm_update_dr7(vcpu);
                }

                kvm_x86_ops->queue_exception(vcpu, vcpu->arch.exception.nr,
                                          vcpu->arch.exception.has_error_code,
                                          vcpu->arch.exception.error_code,
                                          vcpu->arch.exception.reinject);
                return 0;
        }

        if (vcpu->arch.nmi_injected) {
                kvm_x86_ops->set_nmi(vcpu);
                return 0;
        }

        if (vcpu->arch.interrupt.pending) {
                kvm_x86_ops->set_irq(vcpu);
                return 0;
        }

        if (is_guest_mode(vcpu) && kvm_x86_ops->check_nested_events) {
                r = kvm_x86_ops->check_nested_events(vcpu, req_int_win);
                if (r != 0)
                        return r;
        }

        /* try to inject new event if pending */
        if (vcpu->arch.nmi_pending) {
                if (kvm_x86_ops->nmi_allowed(vcpu)) {
                        --vcpu->arch.nmi_pending;
                        vcpu->arch.nmi_injected = true;
                        kvm_x86_ops->set_nmi(vcpu);
                }
        } else if (kvm_cpu_has_injectable_intr(vcpu)) {
                /*
                 * Because interrupts can be injected asynchronously, we are
                 * calling check_nested_events again here to avoid a race condition.
                 * See https://lkml.org/lkml/2014/7/2/60 for discussion about this
                 * proposal and current concerns.  Perhaps we should be setting
                 * KVM_REQ_EVENT only on certain events and not unconditionally?
                 */
                if (is_guest_mode(vcpu) && kvm_x86_ops->check_nested_events) {
                        r = kvm_x86_ops->check_nested_events(vcpu, req_int_win);
                        if (r != 0)
                                return r;
                }
                if (kvm_x86_ops->interrupt_allowed(vcpu)) {
                        kvm_queue_interrupt(vcpu, kvm_cpu_get_interrupt(vcpu),
                                            false);
                        kvm_x86_ops->set_irq(vcpu);
                }
        }
        return 0;
}

static void process_nmi(struct kvm_vcpu *vcpu)
{
        unsigned limit = 2;

        /*
         * x86 is limited to one NMI running, and one NMI pending after it.
         * If an NMI is already in progress, limit further NMIs to just one.
         * Otherwise, allow two (and we'll inject the first one immediately).
         */
        if (kvm_x86_ops->get_nmi_mask(vcpu) || vcpu->arch.nmi_injected)
                limit = 1;

        vcpu->arch.nmi_pending += atomic_xchg(&vcpu->arch.nmi_queued, 0);
        vcpu->arch.nmi_pending = min(vcpu->arch.nmi_pending, limit);
        kvm_make_request(KVM_REQ_EVENT, vcpu);
}

#define put_smstate(type, buf, offset, val)                       \
        *(type *)((buf) + (offset) - 0x7e00) = val

static u32 process_smi_get_segment_flags(struct kvm_segment *seg)
{
        u32 flags = 0;
        flags |= seg->g       << 23;
        flags |= seg->db      << 22;
        flags |= seg->l       << 21;
        flags |= seg->avl     << 20;
        flags |= seg->present << 15;
        flags |= seg->dpl     << 13;
        flags |= seg->s       << 12;
        flags |= seg->type    << 8;
        return flags;
}

static void process_smi_save_seg_32(struct kvm_vcpu *vcpu, char *buf, int n)
{
        struct kvm_segment seg;
        int offset;

        kvm_get_segment(vcpu, &seg, n);
        put_smstate(u32, buf, 0x7fa8 + n * 4, seg.selector);

        if (n < 3)
                offset = 0x7f84 + n * 12;
        else
                offset = 0x7f2c + (n - 3) * 12;

        put_smstate(u32, buf, offset + 8, seg.base);
        put_smstate(u32, buf, offset + 4, seg.limit);
        put_smstate(u32, buf, offset, process_smi_get_segment_flags(&seg));
}

static void process_smi_save_seg_64(struct kvm_vcpu *vcpu, char *buf, int n)
{
        struct kvm_segment seg;
        int offset;
        u16 flags;

        kvm_get_segment(vcpu, &seg, n);
        offset = 0x7e00 + n * 16;

        flags = process_smi_get_segment_flags(&seg) >> 8;
        put_smstate(u16, buf, offset, seg.selector);
        put_smstate(u16, buf, offset + 2, flags);
        put_smstate(u32, buf, offset + 4, seg.limit);
        put_smstate(u64, buf, offset + 8, seg.base);
}

static void process_smi_save_state_32(struct kvm_vcpu *vcpu, char *buf)
{
        struct desc_ptr dt;
        struct kvm_segment seg;
        unsigned long val;
        int i;

        put_smstate(u32, buf, 0x7ffc, kvm_read_cr0(vcpu));
        put_smstate(u32, buf, 0x7ff8, kvm_read_cr3(vcpu));
        put_smstate(u32, buf, 0x7ff4, kvm_get_rflags(vcpu));
        put_smstate(u32, buf, 0x7ff0, kvm_rip_read(vcpu));

        for (i = 0; i < 8; i++)
                put_smstate(u32, buf, 0x7fd0 + i * 4, kvm_register_read(vcpu, i));

        kvm_get_dr(vcpu, 6, &val);
        put_smstate(u32, buf, 0x7fcc, (u32)val);
        kvm_get_dr(vcpu, 7, &val);
        put_smstate(u32, buf, 0x7fc8, (u32)val);

        kvm_get_segment(vcpu, &seg, VCPU_SREG_TR);
        put_smstate(u32, buf, 0x7fc4, seg.selector);
        put_smstate(u32, buf, 0x7f64, seg.base);
        put_smstate(u32, buf, 0x7f60, seg.limit);
        put_smstate(u32, buf, 0x7f5c, process_smi_get_segment_flags(&seg));

        kvm_get_segment(vcpu, &seg, VCPU_SREG_LDTR);
        put_smstate(u32, buf, 0x7fc0, seg.selector);
        put_smstate(u32, buf, 0x7f80, seg.base);
        put_smstate(u32, buf, 0x7f7c, seg.limit);
        put_smstate(u32, buf, 0x7f78, process_smi_get_segment_flags(&seg));

        kvm_x86_ops->get_gdt(vcpu, &dt);
        put_smstate(u32, buf, 0x7f74, dt.address);
        put_smstate(u32, buf, 0x7f70, dt.size);

        kvm_x86_ops->get_idt(vcpu, &dt);
        put_smstate(u32, buf, 0x7f58, dt.address);
        put_smstate(u32, buf, 0x7f54, dt.size);

        for (i = 0; i < 6; i++)
                process_smi_save_seg_32(vcpu, buf, i);

        put_smstate(u32, buf, 0x7f14, kvm_read_cr4(vcpu));

        /* revision id */
        put_smstate(u32, buf, 0x7efc, 0x00020000);
        put_smstate(u32, buf, 0x7ef8, vcpu->arch.smbase);
}

static void process_smi_save_state_64(struct kvm_vcpu *vcpu, char *buf)
{
#ifdef CONFIG_X86_64
        struct desc_ptr dt;
        struct kvm_segment seg;
        unsigned long val;
        int i;

        for (i = 0; i < 16; i++)
                put_smstate(u64, buf, 0x7ff8 - i * 8, kvm_register_read(vcpu, i));

        put_smstate(u64, buf, 0x7f78, kvm_rip_read(vcpu));
        put_smstate(u32, buf, 0x7f70, kvm_get_rflags(vcpu));

        kvm_get_dr(vcpu, 6, &val);
        put_smstate(u64, buf, 0x7f68, val);
        kvm_get_dr(vcpu, 7, &val);
        put_smstate(u64, buf, 0x7f60, val);

        put_smstate(u64, buf, 0x7f58, kvm_read_cr0(vcpu));
        put_smstate(u64, buf, 0x7f50, kvm_read_cr3(vcpu));
        put_smstate(u64, buf, 0x7f48, kvm_read_cr4(vcpu));

        put_smstate(u32, buf, 0x7f00, vcpu->arch.smbase);

        /* revision id */
        put_smstate(u32, buf, 0x7efc, 0x00020064);

        put_smstate(u64, buf, 0x7ed0, vcpu->arch.efer);

        kvm_get_segment(vcpu, &seg, VCPU_SREG_TR);
        put_smstate(u16, buf, 0x7e90, seg.selector);
        put_smstate(u16, buf, 0x7e92, process_smi_get_segment_flags(&seg) >> 8);
        put_smstate(u32, buf, 0x7e94, seg.limit);
        put_smstate(u64, buf, 0x7e98, seg.base);

        kvm_x86_ops->get_idt(vcpu, &dt);
        put_smstate(u32, buf, 0x7e84, dt.size);
        put_smstate(u64, buf, 0x7e88, dt.address);

        kvm_get_segment(vcpu, &seg, VCPU_SREG_LDTR);
        put_smstate(u16, buf, 0x7e70, seg.selector);
        put_smstate(u16, buf, 0x7e72, process_smi_get_segment_flags(&seg) >> 8);
        put_smstate(u32, buf, 0x7e74, seg.limit);
        put_smstate(u64, buf, 0x7e78, seg.base);

        kvm_x86_ops->get_gdt(vcpu, &dt);
        put_smstate(u32, buf, 0x7e64, dt.size);
        put_smstate(u64, buf, 0x7e68, dt.address);

        for (i = 0; i < 6; i++)
                process_smi_save_seg_64(vcpu, buf, i);
#else
        WARN_ON_ONCE(1);
#endif
}

static void process_smi(struct kvm_vcpu *vcpu)
{
        struct kvm_segment cs, ds;
        char buf[512];
        u32 cr0;

        if (is_smm(vcpu)) {
                vcpu->arch.smi_pending = true;
                return;
        }

        trace_kvm_enter_smm(vcpu->vcpu_id, vcpu->arch.smbase, true);
        vcpu->arch.hflags |= HF_SMM_MASK;
        memset(buf, 0, 512);
        if (guest_cpuid_has_longmode(vcpu))
                process_smi_save_state_64(vcpu, buf);
        else
                process_smi_save_state_32(vcpu, buf);

        kvm_vcpu_write_guest(vcpu, vcpu->arch.smbase + 0xfe00, buf, sizeof(buf));

        if (kvm_x86_ops->get_nmi_mask(vcpu))
                vcpu->arch.hflags |= HF_SMM_INSIDE_NMI_MASK;
        else
                kvm_x86_ops->set_nmi_mask(vcpu, true);

        kvm_set_rflags(vcpu, X86_EFLAGS_FIXED);
        kvm_rip_write(vcpu, 0x8000);

        cr0 = vcpu->arch.cr0 & ~(X86_CR0_PE | X86_CR0_EM | X86_CR0_TS | X86_CR0_PG);
        kvm_x86_ops->set_cr0(vcpu, cr0);
        vcpu->arch.cr0 = cr0;

        kvm_x86_ops->set_cr4(vcpu, 0);

        __kvm_set_dr(vcpu, 7, DR7_FIXED_1);

        cs.selector = (vcpu->arch.smbase >> 4) & 0xffff;
        cs.base = vcpu->arch.smbase;

        ds.selector = 0;
        ds.base = 0;

        cs.limit    = ds.limit = 0xffffffff;
        cs.type     = ds.type = 0x3;
        cs.dpl      = ds.dpl = 0;
        cs.db       = ds.db = 0;
        cs.s        = ds.s = 1;
        cs.l        = ds.l = 0;
        cs.g        = ds.g = 1;
        cs.avl      = ds.avl = 0;
        cs.present  = ds.present = 1;
        cs.unusable = ds.unusable = 0;
        cs.padding  = ds.padding = 0;

        kvm_set_segment(vcpu, &cs, VCPU_SREG_CS);
        kvm_set_segment(vcpu, &ds, VCPU_SREG_DS);
        kvm_set_segment(vcpu, &ds, VCPU_SREG_ES);
        kvm_set_segment(vcpu, &ds, VCPU_SREG_FS);
        kvm_set_segment(vcpu, &ds, VCPU_SREG_GS);
        kvm_set_segment(vcpu, &ds, VCPU_SREG_SS);

        if (guest_cpuid_has_longmode(vcpu))
                kvm_x86_ops->set_efer(vcpu, 0);

        kvm_update_cpuid(vcpu);
        kvm_mmu_reset_context(vcpu);
}

static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu)
{
        u64 eoi_exit_bitmap[4];
        u32 tmr[8];

        if (!kvm_apic_hw_enabled(vcpu->arch.apic))
                return;

        memset(eoi_exit_bitmap, 0, 32);
        memset(tmr, 0, 32);

        kvm_ioapic_scan_entry(vcpu, eoi_exit_bitmap, tmr);
        kvm_x86_ops->load_eoi_exitmap(vcpu, eoi_exit_bitmap);
        kvm_apic_update_tmr(vcpu, tmr);
}

static void kvm_vcpu_flush_tlb(struct kvm_vcpu *vcpu)
{
        ++vcpu->stat.tlb_flush;
        kvm_x86_ops->tlb_flush(vcpu);
}

void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu)
{
        struct page *page = NULL;

        if (!irqchip_in_kernel(vcpu->kvm))
                return;

        if (!kvm_x86_ops->set_apic_access_page_addr)
                return;

        page = gfn_to_page(vcpu->kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT);
        if (is_error_page(page))
                return;
        kvm_x86_ops->set_apic_access_page_addr(vcpu, page_to_phys(page));

        /*
         * Do not pin apic access page in memory, the MMU notifier
         * will call us again if it is migrated or swapped out.
         */
        put_page(page);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_reload_apic_access_page);

void kvm_arch_mmu_notifier_invalidate_page(struct kvm *kvm,
                                           unsigned long address)
{
        /*
         * The physical address of apic access page is stored in the VMCS.
         * Update it when it becomes invalid.
         */
        if (address == gfn_to_hva(kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT))
                kvm_make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD);
}

/*
 * Returns 1 to let vcpu_run() continue the guest execution loop without
 * exiting to the userspace.  Otherwise, the value will be returned to the
 * userspace.
 */
static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
{
        int r;
        bool req_int_win = !irqchip_in_kernel(vcpu->kvm) &&
                vcpu->run->request_interrupt_window;
        bool req_immediate_exit = false;

        if (vcpu->requests) {
                if (kvm_check_request(KVM_REQ_MMU_RELOAD, vcpu))
                        kvm_mmu_unload(vcpu);
                if (kvm_check_request(KVM_REQ_MIGRATE_TIMER, vcpu))
                        __kvm_migrate_timers(vcpu);
                if (kvm_check_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu))
                        kvm_gen_update_masterclock(vcpu->kvm);
                if (kvm_check_request(KVM_REQ_GLOBAL_CLOCK_UPDATE, vcpu))
                        kvm_gen_kvmclock_update(vcpu);
                if (kvm_check_request(KVM_REQ_CLOCK_UPDATE, vcpu)) {
                        r = kvm_guest_time_update(vcpu);
                        if (unlikely(r))
                                goto out;
                }
                if (kvm_check_request(KVM_REQ_MMU_SYNC, vcpu))
                        kvm_mmu_sync_roots(vcpu);
                if (kvm_check_request(KVM_REQ_TLB_FLUSH, vcpu))
                        kvm_vcpu_flush_tlb(vcpu);
                if (kvm_check_request(KVM_REQ_REPORT_TPR_ACCESS, vcpu)) {
                        vcpu->run->exit_reason = KVM_EXIT_TPR_ACCESS;
                        r = 0;
                        goto out;
                }
                if (kvm_check_request(KVM_REQ_TRIPLE_FAULT, vcpu)) {
                        vcpu->run->exit_reason = KVM_EXIT_SHUTDOWN;
                        r = 0;
                        goto out;
                }
                if (kvm_check_request(KVM_REQ_DEACTIVATE_FPU, vcpu)) {
                        vcpu->fpu_active = 0;
                        kvm_x86_ops->fpu_deactivate(vcpu);
                }
                if (kvm_check_request(KVM_REQ_APF_HALT, vcpu)) {
                        /* Page is swapped out. Do synthetic halt */
                        vcpu->arch.apf.halted = true;
                        r = 1;
                        goto out;
                }
                if (kvm_check_request(KVM_REQ_STEAL_UPDATE, vcpu))
                        record_steal_time(vcpu);
                if (kvm_check_request(KVM_REQ_SMI, vcpu))
                        process_smi(vcpu);
                if (kvm_check_request(KVM_REQ_NMI, vcpu))
                        process_nmi(vcpu);
                if (kvm_check_request(KVM_REQ_PMU, vcpu))
                        kvm_pmu_handle_event(vcpu);
                if (kvm_check_request(KVM_REQ_PMI, vcpu))
                        kvm_pmu_deliver_pmi(vcpu);
                if (kvm_check_request(KVM_REQ_SCAN_IOAPIC, vcpu))
                        vcpu_scan_ioapic(vcpu);
                if (kvm_check_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu))
                        kvm_vcpu_reload_apic_access_page(vcpu);
        }

        if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) {
                kvm_apic_accept_events(vcpu);
                if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) {
                        r = 1;
                        goto out;
                }

                if (inject_pending_event(vcpu, req_int_win) != 0)
                        req_immediate_exit = true;
                /* enable NMI/IRQ window open exits if needed */
                else if (vcpu->arch.nmi_pending)
                        kvm_x86_ops->enable_nmi_window(vcpu);
                else if (kvm_cpu_has_injectable_intr(vcpu) || req_int_win)
                        kvm_x86_ops->enable_irq_window(vcpu);

                if (kvm_lapic_enabled(vcpu)) {
                        /*
                         * Update architecture specific hints for APIC
                         * virtual interrupt delivery.
                         */
                        if (kvm_x86_ops->hwapic_irr_update)
                                kvm_x86_ops->hwapic_irr_update(vcpu,
                                        kvm_lapic_find_highest_irr(vcpu));
                        update_cr8_intercept(vcpu);
                        kvm_lapic_sync_to_vapic(vcpu);
                }
        }

        r = kvm_mmu_reload(vcpu);
        if (unlikely(r)) {
                goto cancel_injection;
        }

        preempt_disable();

        kvm_x86_ops->prepare_guest_switch(vcpu);
        if (vcpu->fpu_active)
                kvm_load_guest_fpu(vcpu);
        kvm_load_guest_xcr0(vcpu);

        vcpu->mode = IN_GUEST_MODE;

        srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);

        /* We should set ->mode before check ->requests,
         * see the comment in make_all_cpus_request.
         */
        smp_mb__after_srcu_read_unlock();

        local_irq_disable();

        if (vcpu->mode == EXITING_GUEST_MODE || vcpu->requests
            || need_resched() || signal_pending(current)) {
                vcpu->mode = OUTSIDE_GUEST_MODE;
                smp_wmb();
                local_irq_enable();
                preempt_enable();
                vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
                r = 1;
                goto cancel_injection;
        }

        if (req_immediate_exit)
                smp_send_reschedule(vcpu->cpu);

        __kvm_guest_enter();

        if (unlikely(vcpu->arch.switch_db_regs)) {
                set_debugreg(0, 7);
                set_debugreg(vcpu->arch.eff_db[0], 0);
                set_debugreg(vcpu->arch.eff_db[1], 1);
                set_debugreg(vcpu->arch.eff_db[2], 2);
                set_debugreg(vcpu->arch.eff_db[3], 3);
                set_debugreg(vcpu->arch.dr6, 6);
                vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_RELOAD;
        }

        trace_kvm_entry(vcpu->vcpu_id);
        wait_lapic_expire(vcpu);
        kvm_x86_ops->run(vcpu);

        /*
         * Do this here before restoring debug registers on the host.  And
         * since we do this before handling the vmexit, a DR access vmexit
         * can (a) read the correct value of the debug registers, (b) set
         * KVM_DEBUGREG_WONT_EXIT again.
         */
        if (unlikely(vcpu->arch.switch_db_regs & KVM_DEBUGREG_WONT_EXIT)) {
                int i;

                WARN_ON(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP);
                kvm_x86_ops->sync_dirty_debug_regs(vcpu);
                for (i = 0; i < KVM_NR_DB_REGS; i++)
                        vcpu->arch.eff_db[i] = vcpu->arch.db[i];
        }

        /*
         * If the guest has used debug registers, at least dr7
         * will be disabled while returning to the host.
         * If we don't have active breakpoints in the host, we don't
         * care about the messed up debug address registers. But if
         * we have some of them active, restore the old state.
         */
        if (hw_breakpoint_active())
                hw_breakpoint_restore();

        vcpu->arch.last_guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu,
                                                           native_read_tsc());

        vcpu->mode = OUTSIDE_GUEST_MODE;
        smp_wmb();

        /* Interrupt is enabled by handle_external_intr() */
        kvm_x86_ops->handle_external_intr(vcpu);

        ++vcpu->stat.exits;

        /*
         * We must have an instruction between local_irq_enable() and
         * kvm_guest_exit(), so the timer interrupt isn't delayed by
         * the interrupt shadow.  The stat.exits increment will do nicely.
         * But we need to prevent reordering, hence this barrier():
         */
        barrier();

        kvm_guest_exit();

        preempt_enable();

        vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);

        /*
         * Profile KVM exit RIPs:
         */
        if (unlikely(prof_on == KVM_PROFILING)) {
                unsigned long rip = kvm_rip_read(vcpu);
                profile_hit(KVM_PROFILING, (void *)rip);
        }

        if (unlikely(vcpu->arch.tsc_always_catchup))
                kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);

        if (vcpu->arch.apic_attention)
                kvm_lapic_sync_from_vapic(vcpu);

        r = kvm_x86_ops->handle_exit(vcpu);
        return r;

cancel_injection:
        kvm_x86_ops->cancel_injection(vcpu);
        if (unlikely(vcpu->arch.apic_attention))
                kvm_lapic_sync_from_vapic(vcpu);
out:
        return r;
}

static inline int vcpu_block(struct kvm *kvm, struct kvm_vcpu *vcpu)
{
        if (!kvm_arch_vcpu_runnable(vcpu)) {
                srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
                kvm_vcpu_block(vcpu);
                vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);
                if (!kvm_check_request(KVM_REQ_UNHALT, vcpu))
                        return 1;
        }

        kvm_apic_accept_events(vcpu);
        switch(vcpu->arch.mp_state) {
        case KVM_MP_STATE_HALTED:
                vcpu->arch.pv.pv_unhalted = false;
                vcpu->arch.mp_state =
                        KVM_MP_STATE_RUNNABLE;
        case KVM_MP_STATE_RUNNABLE:
                vcpu->arch.apf.halted = false;
                break;
        case KVM_MP_STATE_INIT_RECEIVED:
                break;
        default:
                return -EINTR;
                break;
        }
        return 1;
}

static int vcpu_run(struct kvm_vcpu *vcpu)
{
        int r;
        struct kvm *kvm = vcpu->kvm;

        vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);

        for (;;) {
                if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE &&
                    !vcpu->arch.apf.halted)
                        r = vcpu_enter_guest(vcpu);
                else
                        r = vcpu_block(kvm, vcpu);
                if (r <= 0)
                        break;

                clear_bit(KVM_REQ_PENDING_TIMER, &vcpu->requests);
                if (kvm_cpu_has_pending_timer(vcpu))
                        kvm_inject_pending_timer_irqs(vcpu);

                if (dm_request_for_irq_injection(vcpu)) {
                        r = -EINTR;
                        vcpu->run->exit_reason = KVM_EXIT_INTR;
                        ++vcpu->stat.request_irq_exits;
                        break;
                }

                kvm_check_async_pf_completion(vcpu);

                if (signal_pending(current)) {
                        r = -EINTR;
                        vcpu->run->exit_reason = KVM_EXIT_INTR;
                        ++vcpu->stat.signal_exits;
                        break;
                }
                if (need_resched()) {
                        srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
                        cond_resched();
                        vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);
                }
        }

        srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);

        return r;
}

static inline int complete_emulated_io(struct kvm_vcpu *vcpu)
{
        int r;
        vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
        r = emulate_instruction(vcpu, EMULTYPE_NO_DECODE);
        srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
        if (r != EMULATE_DONE)
                return 0;
        return 1;
}

static int complete_emulated_pio(struct kvm_vcpu *vcpu)
{
        BUG_ON(!vcpu->arch.pio.count);

        return complete_emulated_io(vcpu);
}

/*
 * Implements the following, as a state machine:
 *
 * read:
 *   for each fragment
 *     for each mmio piece in the fragment
 *       write gpa, len
 *       exit
 *       copy data
 *   execute insn
 *
 * write:
 *   for each fragment
 *     for each mmio piece in the fragment
 *       write gpa, len
 *       copy data
 *       exit
 */
static int complete_emulated_mmio(struct kvm_vcpu *vcpu)
{
        struct kvm_run *run = vcpu->run;
        struct kvm_mmio_fragment *frag;
        unsigned len;

        BUG_ON(!vcpu->mmio_needed);

        /* Complete previous fragment */
        frag = &vcpu->mmio_fragments[vcpu->mmio_cur_fragment];
        len = min(8u, frag->len);
        if (!vcpu->mmio_is_write)
                memcpy(frag->data, run->mmio.data, len);

        if (frag->len <= 8) {
                /* Switch to the next fragment. */
                frag++;
                vcpu->mmio_cur_fragment++;
        } else {
                /* Go forward to the next mmio piece. */
                frag->data += len;
                frag->gpa += len;
                frag->len -= len;
        }

        if (vcpu->mmio_cur_fragment >= vcpu->mmio_nr_fragments) {
                vcpu->mmio_needed = 0;

                /* FIXME: return into emulator if single-stepping.  */
                if (vcpu->mmio_is_write)
                        return 1;
                vcpu->mmio_read_completed = 1;
                return complete_emulated_io(vcpu);
        }

        run->exit_reason = KVM_EXIT_MMIO;
        run->mmio.phys_addr = frag->gpa;
        if (vcpu->mmio_is_write)
                memcpy(run->mmio.data, frag->data, min(8u, frag->len));
        run->mmio.len = min(8u, frag->len);
        run->mmio.is_write = vcpu->mmio_is_write;
        vcpu->arch.complete_userspace_io = complete_emulated_mmio;
        return 0;
}


int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
        struct fpu *fpu = &current->thread.fpu;
        int r;
        sigset_t sigsaved;

        fpu__activate_curr(fpu);

        if (vcpu->sigset_active)
                sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);

        if (unlikely(vcpu->arch.mp_state == KVM_MP_STATE_UNINITIALIZED)) {
                kvm_vcpu_block(vcpu);
                kvm_apic_accept_events(vcpu);
                clear_bit(KVM_REQ_UNHALT, &vcpu->requests);
                r = -EAGAIN;
                goto out;
        }

        /* re-sync apic's tpr */
        if (!irqchip_in_kernel(vcpu->kvm)) {
                if (kvm_set_cr8(vcpu, kvm_run->cr8) != 0) {
                        r = -EINVAL;
                        goto out;
                }
        }

        if (unlikely(vcpu->arch.complete_userspace_io)) {
                int (*cui)(struct kvm_vcpu *) = vcpu->arch.complete_userspace_io;
                vcpu->arch.complete_userspace_io = NULL;
                r = cui(vcpu);
                if (r <= 0)
                        goto out;
        } else
                WARN_ON(vcpu->arch.pio.count || vcpu->mmio_needed);

        r = vcpu_run(vcpu);

out:
        post_kvm_run_save(vcpu);
        if (vcpu->sigset_active)
                sigprocmask(SIG_SETMASK, &sigsaved, NULL);

        return r;
}

int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
{
        if (vcpu->arch.emulate_regs_need_sync_to_vcpu) {
                /*
                 * We are here if userspace calls get_regs() in the middle of
                 * instruction emulation. Registers state needs to be copied
                 * back from emulation context to vcpu. Userspace shouldn't do
                 * that usually, but some bad designed PV devices (vmware
                 * backdoor interface) need this to work
                 */
                emulator_writeback_register_cache(&vcpu->arch.emulate_ctxt);
                vcpu->arch.emulate_regs_need_sync_to_vcpu = false;
        }
        regs->rax = kvm_register_read(vcpu, VCPU_REGS_RAX);
        regs->rbx = kvm_register_read(vcpu, VCPU_REGS_RBX);
        regs->rcx = kvm_register_read(vcpu, VCPU_REGS_RCX);
        regs->rdx = kvm_register_read(vcpu, VCPU_REGS_RDX);
        regs->rsi = kvm_register_read(vcpu, VCPU_REGS_RSI);
        regs->rdi = kvm_register_read(vcpu, VCPU_REGS_RDI);
        regs->rsp = kvm_register_read(vcpu, VCPU_REGS_RSP);
        regs->rbp = kvm_register_read(vcpu, VCPU_REGS_RBP);
#ifdef CONFIG_X86_64
        regs->r8 = kvm_register_read(vcpu, VCPU_REGS_R8);
        regs->r9 = kvm_register_read(vcpu, VCPU_REGS_R9);
        regs->r10 = kvm_register_read(vcpu, VCPU_REGS_R10);
        regs->r11 = kvm_register_read(vcpu, VCPU_REGS_R11);
        regs->r12 = kvm_register_read(vcpu, VCPU_REGS_R12);
        regs->r13 = kvm_register_read(vcpu, VCPU_REGS_R13);
        regs->r14 = kvm_register_read(vcpu, VCPU_REGS_R14);
        regs->r15 = kvm_register_read(vcpu, VCPU_REGS_R15);
#endif

        regs->rip = kvm_rip_read(vcpu);
        regs->rflags = kvm_get_rflags(vcpu);

        return 0;
}

int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
{
        vcpu->arch.emulate_regs_need_sync_from_vcpu = true;
        vcpu->arch.emulate_regs_need_sync_to_vcpu = false;

        kvm_register_write(vcpu, VCPU_REGS_RAX, regs->rax);
        kvm_register_write(vcpu, VCPU_REGS_RBX, regs->rbx);
        kvm_register_write(vcpu, VCPU_REGS_RCX, regs->rcx);
        kvm_register_write(vcpu, VCPU_REGS_RDX, regs->rdx);
        kvm_register_write(vcpu, VCPU_REGS_RSI, regs->rsi);
        kvm_register_write(vcpu, VCPU_REGS_RDI, regs->rdi);
        kvm_register_write(vcpu, VCPU_REGS_RSP, regs->rsp);
        kvm_register_write(vcpu, VCPU_REGS_RBP, regs->rbp);
#ifdef CONFIG_X86_64
        kvm_register_write(vcpu, VCPU_REGS_R8, regs->r8);
        kvm_register_write(vcpu, VCPU_REGS_R9, regs->r9);
        kvm_register_write(vcpu, VCPU_REGS_R10, regs->r10);
        kvm_register_write(vcpu, VCPU_REGS_R11, regs->r11);
        kvm_register_write(vcpu, VCPU_REGS_R12, regs->r12);
        kvm_register_write(vcpu, VCPU_REGS_R13, regs->r13);
        kvm_register_write(vcpu, VCPU_REGS_R14, regs->r14);
        kvm_register_write(vcpu, VCPU_REGS_R15, regs->r15);
#endif

        kvm_rip_write(vcpu, regs->rip);
        kvm_set_rflags(vcpu, regs->rflags);

        vcpu->arch.exception.pending = false;

        kvm_make_request(KVM_REQ_EVENT, vcpu);

        return 0;
}

void kvm_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l)
{
        struct kvm_segment cs;

        kvm_get_segment(vcpu, &cs, VCPU_SREG_CS);
        *db = cs.db;
        *l = cs.l;
}
EXPORT_SYMBOL_GPL(kvm_get_cs_db_l_bits);

int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
                                  struct kvm_sregs *sregs)
{
        struct desc_ptr dt;

        kvm_get_segment(vcpu, &sregs->cs, VCPU_SREG_CS);
        kvm_get_segment(vcpu, &sregs->ds, VCPU_SREG_DS);
        kvm_get_segment(vcpu, &sregs->es, VCPU_SREG_ES);
        kvm_get_segment(vcpu, &sregs->fs, VCPU_SREG_FS);
        kvm_get_segment(vcpu, &sregs->gs, VCPU_SREG_GS);
        kvm_get_segment(vcpu, &sregs->ss, VCPU_SREG_SS);

        kvm_get_segment(vcpu, &sregs->tr, VCPU_SREG_TR);
        kvm_get_segment(vcpu, &sregs->ldt, VCPU_SREG_LDTR);

        kvm_x86_ops->get_idt(vcpu, &dt);
        sregs->idt.limit = dt.size;
        sregs->idt.base = dt.address;
        kvm_x86_ops->get_gdt(vcpu, &dt);
        sregs->gdt.limit = dt.size;
        sregs->gdt.base = dt.address;

        sregs->cr0 = kvm_read_cr0(vcpu);
        sregs->cr2 = vcpu->arch.cr2;
        sregs->cr3 = kvm_read_cr3(vcpu);
        sregs->cr4 = kvm_read_cr4(vcpu);
        sregs->cr8 = kvm_get_cr8(vcpu);
        sregs->efer = vcpu->arch.efer;
        sregs->apic_base = kvm_get_apic_base(vcpu);

        memset(sregs->interrupt_bitmap, 0, sizeof sregs->interrupt_bitmap);

        if (vcpu->arch.interrupt.pending && !vcpu->arch.interrupt.soft)
                set_bit(vcpu->arch.interrupt.nr,
                        (unsigned long *)sregs->interrupt_bitmap);

        return 0;
}

int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
                                    struct kvm_mp_state *mp_state)
{
        kvm_apic_accept_events(vcpu);
        if (vcpu->arch.mp_state == KVM_MP_STATE_HALTED &&
                                        vcpu->arch.pv.pv_unhalted)
                mp_state->mp_state = KVM_MP_STATE_RUNNABLE;
        else
                mp_state->mp_state = vcpu->arch.mp_state;

        return 0;
}

int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
                                    struct kvm_mp_state *mp_state)
{
        if (!kvm_vcpu_has_lapic(vcpu) &&
            mp_state->mp_state != KVM_MP_STATE_RUNNABLE)
                return -EINVAL;

        if (mp_state->mp_state == KVM_MP_STATE_SIPI_RECEIVED) {
                vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED;
                set_bit(KVM_APIC_SIPI, &vcpu->arch.apic->pending_events);
        } else
                vcpu->arch.mp_state = mp_state->mp_state;
        kvm_make_request(KVM_REQ_EVENT, vcpu);
        return 0;
}

int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int idt_index,
                    int reason, bool has_error_code, u32 error_code)
{
        struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
        int ret;

        init_emulate_ctxt(vcpu);

        ret = emulator_task_switch(ctxt, tss_selector, idt_index, reason,
                                   has_error_code, error_code);

        if (ret)
                return EMULATE_FAIL;

        kvm_rip_write(vcpu, ctxt->eip);
        kvm_set_rflags(vcpu, ctxt->eflags);
        kvm_make_request(KVM_REQ_EVENT, vcpu);
        return EMULATE_DONE;
}
EXPORT_SYMBOL_GPL(kvm_task_switch);

int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
                                  struct kvm_sregs *sregs)
{
        struct msr_data apic_base_msr;
        int mmu_reset_needed = 0;
        int pending_vec, max_bits, idx;
        struct desc_ptr dt;

        if (!guest_cpuid_has_xsave(vcpu) && (sregs->cr4 & X86_CR4_OSXSAVE))
                return -EINVAL;

        dt.size = sregs->idt.limit;
        dt.address = sregs->idt.base;
        kvm_x86_ops->set_idt(vcpu, &dt);
        dt.size = sregs->gdt.limit;
        dt.address = sregs->gdt.base;
        kvm_x86_ops->set_gdt(vcpu, &dt);

        vcpu->arch.cr2 = sregs->cr2;
        mmu_reset_needed |= kvm_read_cr3(vcpu) != sregs->cr3;
        vcpu->arch.cr3 = sregs->cr3;
        __set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail);

        kvm_set_cr8(vcpu, sregs->cr8);

        mmu_reset_needed |= vcpu->arch.efer != sregs->efer;
        kvm_x86_ops->set_efer(vcpu, sregs->efer);
        apic_base_msr.data = sregs->apic_base;
        apic_base_msr.host_initiated = true;
        kvm_set_apic_base(vcpu, &apic_base_msr);

        mmu_reset_needed |= kvm_read_cr0(vcpu) != sregs->cr0;
        kvm_x86_ops->set_cr0(vcpu, sregs->cr0);
        vcpu->arch.cr0 = sregs->cr0;

        mmu_reset_needed |= kvm_read_cr4(vcpu) != sregs->cr4;
        kvm_x86_ops->set_cr4(vcpu, sregs->cr4);
        if (sregs->cr4 & X86_CR4_OSXSAVE)
                kvm_update_cpuid(vcpu);

        idx = srcu_read_lock(&vcpu->kvm->srcu);
        if (!is_long_mode(vcpu) && is_pae(vcpu)) {
                load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu));
                mmu_reset_needed = 1;
        }
        srcu_read_unlock(&vcpu->kvm->srcu, idx);

        if (mmu_reset_needed)
                kvm_mmu_reset_context(vcpu);

        max_bits = KVM_NR_INTERRUPTS;
        pending_vec = find_first_bit(
                (const unsigned long *)sregs->interrupt_bitmap, max_bits);
        if (pending_vec < max_bits) {
                kvm_queue_interrupt(vcpu, pending_vec, false);
                pr_debug("Set back pending irq %d\n", pending_vec);
        }

        kvm_set_segment(vcpu, &sregs->cs, VCPU_SREG_CS);
        kvm_set_segment(vcpu, &sregs->ds, VCPU_SREG_DS);
        kvm_set_segment(vcpu, &sregs->es, VCPU_SREG_ES);
        kvm_set_segment(vcpu, &sregs->fs, VCPU_SREG_FS);
        kvm_set_segment(vcpu, &sregs->gs, VCPU_SREG_GS);
        kvm_set_segment(vcpu, &sregs->ss, VCPU_SREG_SS);

        kvm_set_segment(vcpu, &sregs->tr, VCPU_SREG_TR);
        kvm_set_segment(vcpu, &sregs->ldt, VCPU_SREG_LDTR);

        update_cr8_intercept(vcpu);

        /* Older userspace won't unhalt the vcpu on reset. */
        if (kvm_vcpu_is_bsp(vcpu) && kvm_rip_read(vcpu) == 0xfff0 &&
            sregs->cs.selector == 0xf000 && sregs->cs.base == 0xffff0000 &&
            !is_protmode(vcpu))
                vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;

        kvm_make_request(KVM_REQ_EVENT, vcpu);

        return 0;
}

int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
                                        struct kvm_guest_debug *dbg)
{
        unsigned long rflags;
        int i, r;

        if (dbg->control & (KVM_GUESTDBG_INJECT_DB | KVM_GUESTDBG_INJECT_BP)) {
                r = -EBUSY;
                if (vcpu->arch.exception.pending)
                        goto out;
                if (dbg->control & KVM_GUESTDBG_INJECT_DB)
                        kvm_queue_exception(vcpu, DB_VECTOR);
                else
                        kvm_queue_exception(vcpu, BP_VECTOR);
        }

        /*
         * Read rflags as long as potentially injected trace flags are still
         * filtered out.
         */
        rflags = kvm_get_rflags(vcpu);

        vcpu->guest_debug = dbg->control;
        if (!(vcpu->guest_debug & KVM_GUESTDBG_ENABLE))
                vcpu->guest_debug = 0;

        if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
                for (i = 0; i < KVM_NR_DB_REGS; ++i)
                        vcpu->arch.eff_db[i] = dbg->arch.debugreg[i];
                vcpu->arch.guest_debug_dr7 = dbg->arch.debugreg[7];
        } else {
                for (i = 0; i < KVM_NR_DB_REGS; i++)
                        vcpu->arch.eff_db[i] = vcpu->arch.db[i];
        }
        kvm_update_dr7(vcpu);

        if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
                vcpu->arch.singlestep_rip = kvm_rip_read(vcpu) +
                        get_segment_base(vcpu, VCPU_SREG_CS);

        /*
         * Trigger an rflags update that will inject or remove the trace
         * flags.
         */
        kvm_set_rflags(vcpu, rflags);

        kvm_x86_ops->update_db_bp_intercept(vcpu);

        r = 0;

out:

        return r;
}

/*
 * Translate a guest virtual address to a guest physical address.
 */
int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
                                    struct kvm_translation *tr)
{
        unsigned long vaddr = tr->linear_address;
        gpa_t gpa;
        int idx;

        idx = srcu_read_lock(&vcpu->kvm->srcu);
        gpa = kvm_mmu_gva_to_gpa_system(vcpu, vaddr, NULL);
        srcu_read_unlock(&vcpu->kvm->srcu, idx);
        tr->physical_address = gpa;
        tr->valid = gpa != UNMAPPED_GVA;
        tr->writeable = 1;
        tr->usermode = 0;

        return 0;
}

int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
        struct fxregs_state *fxsave =
                        &vcpu->arch.guest_fpu.state.fxsave;

        memcpy(fpu->fpr, fxsave->st_space, 128);
        fpu->fcw = fxsave->cwd;
        fpu->fsw = fxsave->swd;
        fpu->ftwx = fxsave->twd;
        fpu->last_opcode = fxsave->fop;
        fpu->last_ip = fxsave->rip;
        fpu->last_dp = fxsave->rdp;
        memcpy(fpu->xmm, fxsave->xmm_space, sizeof fxsave->xmm_space);

        return 0;
}

int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
        struct fxregs_state *fxsave =
                        &vcpu->arch.guest_fpu.state.fxsave;

        memcpy(fxsave->st_space, fpu->fpr, 128);
        fxsave->cwd = fpu->fcw;
        fxsave->swd = fpu->fsw;
        fxsave->twd = fpu->ftwx;
        fxsave->fop = fpu->last_opcode;
        fxsave->rip = fpu->last_ip;
        fxsave->rdp = fpu->last_dp;
        memcpy(fxsave->xmm_space, fpu->xmm, sizeof fxsave->xmm_space);

        return 0;
}

static void fx_init(struct kvm_vcpu *vcpu)
{
        fpstate_init(&vcpu->arch.guest_fpu.state);
        if (cpu_has_xsaves)
                vcpu->arch.guest_fpu.state.xsave.header.xcomp_bv =
                        host_xcr0 | XSTATE_COMPACTION_ENABLED;

        /*
         * Ensure guest xcr0 is valid for loading
         */
        vcpu->arch.xcr0 = XSTATE_FP;

        vcpu->arch.cr0 |= X86_CR0_ET;
}

void kvm_load_guest_fpu(struct kvm_vcpu *vcpu)
{
        if (vcpu->guest_fpu_loaded)
                return;

        /*
         * Restore all possible states in the guest,
         * and assume host would use all available bits.
         * Guest xcr0 would be loaded later.
         */
        kvm_put_guest_xcr0(vcpu);
        vcpu->guest_fpu_loaded = 1;
        __kernel_fpu_begin();
        __copy_kernel_to_fpregs(&vcpu->arch.guest_fpu.state);
        trace_kvm_fpu(1);
}

void kvm_put_guest_fpu(struct kvm_vcpu *vcpu)
{
        kvm_put_guest_xcr0(vcpu);

        if (!vcpu->guest_fpu_loaded) {
                vcpu->fpu_counter = 0;
                return;
        }

        vcpu->guest_fpu_loaded = 0;
        copy_fpregs_to_fpstate(&vcpu->arch.guest_fpu);
        __kernel_fpu_end();
        ++vcpu->stat.fpu_reload;
        /*
         * If using eager FPU mode, or if the guest is a frequent user
         * of the FPU, just leave the FPU active for next time.
         * Every 255 times fpu_counter rolls over to 0; a guest that uses
         * the FPU in bursts will revert to loading it on demand.
         */
        if (!vcpu->arch.eager_fpu) {
                if (++vcpu->fpu_counter < 5)
                        kvm_make_request(KVM_REQ_DEACTIVATE_FPU, vcpu);
        }
        trace_kvm_fpu(0);
}

void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
{
        kvmclock_reset(vcpu);

        free_cpumask_var(vcpu->arch.wbinvd_dirty_mask);
        kvm_x86_ops->vcpu_free(vcpu);
}

struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
                                                unsigned int id)
{
        struct kvm_vcpu *vcpu;

        if (check_tsc_unstable() && atomic_read(&kvm->online_vcpus) != 0)
                printk_once(KERN_WARNING
                "kvm: SMP vm created on host with unstable TSC; "
                "guest TSC will not be reliable\n");

        vcpu = kvm_x86_ops->vcpu_create(kvm, id);

        return vcpu;
}

int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
{
        int r;

        kvm_vcpu_mtrr_init(vcpu);
        r = vcpu_load(vcpu);
        if (r)
                return r;
        kvm_vcpu_reset(vcpu, false);
        kvm_mmu_setup(vcpu);
        vcpu_put(vcpu);
        return r;
}

void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
{
        struct msr_data msr;
        struct kvm *kvm = vcpu->kvm;

        if (vcpu_load(vcpu))
                return;
        msr.data = 0x0;
        msr.index = MSR_IA32_TSC;
        msr.host_initiated = true;
        kvm_write_tsc(vcpu, &msr);
        vcpu_put(vcpu);

        if (!kvmclock_periodic_sync)
                return;

        schedule_delayed_work(&kvm->arch.kvmclock_sync_work,
                                        KVMCLOCK_SYNC_PERIOD);
}

void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
{
        int r;
        vcpu->arch.apf.msr_val = 0;

        r = vcpu_load(vcpu);
        BUG_ON(r);
        kvm_mmu_unload(vcpu);
        vcpu_put(vcpu);

        kvm_x86_ops->vcpu_free(vcpu);
}

void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
{
        vcpu->arch.hflags = 0;

        atomic_set(&vcpu->arch.nmi_queued, 0);
        vcpu->arch.nmi_pending = 0;
        vcpu->arch.nmi_injected = false;
        kvm_clear_interrupt_queue(vcpu);
        kvm_clear_exception_queue(vcpu);

        memset(vcpu->arch.db, 0, sizeof(vcpu->arch.db));
        kvm_update_dr0123(vcpu);
        vcpu->arch.dr6 = DR6_INIT;
        kvm_update_dr6(vcpu);
        vcpu->arch.dr7 = DR7_FIXED_1;
        kvm_update_dr7(vcpu);

        vcpu->arch.cr2 = 0;

        kvm_make_request(KVM_REQ_EVENT, vcpu);
        vcpu->arch.apf.msr_val = 0;
        vcpu->arch.st.msr_val = 0;

        kvmclock_reset(vcpu);

        kvm_clear_async_pf_completion_queue(vcpu);
        kvm_async_pf_hash_reset(vcpu);
        vcpu->arch.apf.halted = false;

        if (!init_event) {
                kvm_pmu_reset(vcpu);
                vcpu->arch.smbase = 0x30000;
        }

        memset(vcpu->arch.regs, 0, sizeof(vcpu->arch.regs));
        vcpu->arch.regs_avail = ~0;
        vcpu->arch.regs_dirty = ~0;

        kvm_x86_ops->vcpu_reset(vcpu, init_event);
}

void kvm_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector)
{
        struct kvm_segment cs;

        kvm_get_segment(vcpu, &cs, VCPU_SREG_CS);
        cs.selector = vector << 8;
        cs.base = vector << 12;
        kvm_set_segment(vcpu, &cs, VCPU_SREG_CS);
        kvm_rip_write(vcpu, 0);
}

int kvm_arch_hardware_enable(void)
{
        struct kvm *kvm;
        struct kvm_vcpu *vcpu;
        int i;
        int ret;
        u64 local_tsc;
        u64 max_tsc = 0;
        bool stable, backwards_tsc = false;

        kvm_shared_msr_cpu_online();
        ret = kvm_x86_ops->hardware_enable();
        if (ret != 0)
                return ret;

        local_tsc = native_read_tsc();
        stable = !check_tsc_unstable();
        list_for_each_entry(kvm, &vm_list, vm_list) {
                kvm_for_each_vcpu(i, vcpu, kvm) {
                        if (!stable && vcpu->cpu == smp_processor_id())
                                kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
                        if (stable && vcpu->arch.last_host_tsc > local_tsc) {
                                backwards_tsc = true;
                                if (vcpu->arch.last_host_tsc > max_tsc)
                                        max_tsc = vcpu->arch.last_host_tsc;
                        }
                }
        }

        /*
         * Sometimes, even reliable TSCs go backwards.  This happens on
         * platforms that reset TSC during suspend or hibernate actions, but
         * maintain synchronization.  We must compensate.  Fortunately, we can
         * detect that condition here, which happens early in CPU bringup,
         * before any KVM threads can be running.  Unfortunately, we can't
         * bring the TSCs fully up to date with real time, as we aren't yet far
         * enough into CPU bringup that we know how much real time has actually
         * elapsed; our helper function, get_kernel_ns() will be using boot
         * variables that haven't been updated yet.
         *
         * So we simply find the maximum observed TSC above, then record the
         * adjustment to TSC in each VCPU.  When the VCPU later gets loaded,
         * the adjustment will be applied.  Note that we accumulate
         * adjustments, in case multiple suspend cycles happen before some VCPU
         * gets a chance to run again.  In the event that no KVM threads get a
         * chance to run, we will miss the entire elapsed period, as we'll have
         * reset last_host_tsc, so VCPUs will not have the TSC adjusted and may
         * loose cycle time.  This isn't too big a deal, since the loss will be
         * uniform across all VCPUs (not to mention the scenario is extremely
         * unlikely). It is possible that a second hibernate recovery happens
         * much faster than a first, causing the observed TSC here to be
         * smaller; this would require additional padding adjustment, which is
         * why we set last_host_tsc to the local tsc observed here.
         *
         * N.B. - this code below runs only on platforms with reliable TSC,
         * as that is the only way backwards_tsc is set above.  Also note
         * that this runs for ALL vcpus, which is not a bug; all VCPUs should
         * have the same delta_cyc adjustment applied if backwards_tsc
         * is detected.  Note further, this adjustment is only done once,
         * as we reset last_host_tsc on all VCPUs to stop this from being
         * called multiple times (one for each physical CPU bringup).
         *
         * Platforms with unreliable TSCs don't have to deal with this, they
         * will be compensated by the logic in vcpu_load, which sets the TSC to
         * catchup mode.  This will catchup all VCPUs to real time, but cannot
         * guarantee that they stay in perfect synchronization.
         */
        if (backwards_tsc) {
                u64 delta_cyc = max_tsc - local_tsc;
                backwards_tsc_observed = true;
                list_for_each_entry(kvm, &vm_list, vm_list) {
                        kvm_for_each_vcpu(i, vcpu, kvm) {
                                vcpu->arch.tsc_offset_adjustment += delta_cyc;
                                vcpu->arch.last_host_tsc = local_tsc;
                                kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);
                        }

                        /*
                         * We have to disable TSC offset matching.. if you were
                         * booting a VM while issuing an S4 host suspend....
                         * you may have some problem.  Solving this issue is
                         * left as an exercise to the reader.
                         */
                        kvm->arch.last_tsc_nsec = 0;
                        kvm->arch.last_tsc_write = 0;
                }

        }
        return 0;
}

void kvm_arch_hardware_disable(void)
{
        kvm_x86_ops->hardware_disable();
        drop_user_return_notifiers();
}

int kvm_arch_hardware_setup(void)
{
        int r;

        r = kvm_x86_ops->hardware_setup();
        if (r != 0)
                return r;

        kvm_init_msr_list();
        return 0;
}

void kvm_arch_hardware_unsetup(void)
{
        kvm_x86_ops->hardware_unsetup();
}

void kvm_arch_check_processor_compat(void *rtn)
{
        kvm_x86_ops->check_processor_compatibility(rtn);
}

bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu)
{
        return irqchip_in_kernel(vcpu->kvm) == (vcpu->arch.apic != NULL);
}

struct static_key kvm_no_apic_vcpu __read_mostly;

int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
{
        struct page *page;
        struct kvm *kvm;
        int r;

        BUG_ON(vcpu->kvm == NULL);
        kvm = vcpu->kvm;

        vcpu->arch.pv.pv_unhalted = false;
        vcpu->arch.emulate_ctxt.ops = &emulate_ops;
        if (!irqchip_in_kernel(kvm) || kvm_vcpu_is_reset_bsp(vcpu))
                vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
        else
                vcpu->arch.mp_state = KVM_MP_STATE_UNINITIALIZED;

        page = alloc_page(GFP_KERNEL | __GFP_ZERO);
        if (!page) {
                r = -ENOMEM;
                goto fail;
        }
        vcpu->arch.pio_data = page_address(page);

        kvm_set_tsc_khz(vcpu, max_tsc_khz);

        r = kvm_mmu_create(vcpu);
        if (r < 0)
                goto fail_free_pio_data;

        if (irqchip_in_kernel(kvm)) {
                r = kvm_create_lapic(vcpu);
                if (r < 0)
                        goto fail_mmu_destroy;
        } else
                static_key_slow_inc(&kvm_no_apic_vcpu);

        vcpu->arch.mce_banks = kzalloc(KVM_MAX_MCE_BANKS * sizeof(u64) * 4,
                                       GFP_KERNEL);
        if (!vcpu->arch.mce_banks) {
                r = -ENOMEM;
                goto fail_free_lapic;
        }
        vcpu->arch.mcg_cap = KVM_MAX_MCE_BANKS;

        if (!zalloc_cpumask_var(&vcpu->arch.wbinvd_dirty_mask, GFP_KERNEL)) {
                r = -ENOMEM;
                goto fail_free_mce_banks;
        }

        fx_init(vcpu);

        vcpu->arch.ia32_tsc_adjust_msr = 0x0;
        vcpu->arch.pv_time_enabled = false;

        vcpu->arch.guest_supported_xcr0 = 0;
        vcpu->arch.guest_xstate_size = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;

        vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);

        vcpu->arch.pat = MSR_IA32_CR_PAT_DEFAULT;

        kvm_async_pf_hash_reset(vcpu);
        kvm_pmu_init(vcpu);

        return 0;

fail_free_mce_banks:
        kfree(vcpu->arch.mce_banks);
fail_free_lapic:
        kvm_free_lapic(vcpu);
fail_mmu_destroy:
        kvm_mmu_destroy(vcpu);
fail_free_pio_data:
        free_page((unsigned long)vcpu->arch.pio_data);
fail:
        return r;
}

void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
{
        int idx;

        kvm_pmu_destroy(vcpu);
        kfree(vcpu->arch.mce_banks);
        kvm_free_lapic(vcpu);
        idx = srcu_read_lock(&vcpu->kvm->srcu);
        kvm_mmu_destroy(vcpu);
        srcu_read_unlock(&vcpu->kvm->srcu, idx);
        free_page((unsigned long)vcpu->arch.pio_data);
        if (!irqchip_in_kernel(vcpu->kvm))
                static_key_slow_dec(&kvm_no_apic_vcpu);
}

void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu)
{
        kvm_x86_ops->sched_in(vcpu, cpu);
}

int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
{
        if (type)
                return -EINVAL;

        INIT_HLIST_HEAD(&kvm->arch.mask_notifier_list);
        INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);
        INIT_LIST_HEAD(&kvm->arch.zapped_obsolete_pages);
        INIT_LIST_HEAD(&kvm->arch.assigned_dev_head);
        atomic_set(&kvm->arch.noncoherent_dma_count, 0);

        /* Reserve bit 0 of irq_sources_bitmap for userspace irq source */
        set_bit(KVM_USERSPACE_IRQ_SOURCE_ID, &kvm->arch.irq_sources_bitmap);
        /* Reserve bit 1 of irq_sources_bitmap for irqfd-resampler */
        set_bit(KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
                &kvm->arch.irq_sources_bitmap);

        raw_spin_lock_init(&kvm->arch.tsc_write_lock);
        mutex_init(&kvm->arch.apic_map_lock);
        spin_lock_init(&kvm->arch.pvclock_gtod_sync_lock);

        pvclock_update_vm_gtod_copy(kvm);

        INIT_DELAYED_WORK(&kvm->arch.kvmclock_update_work, kvmclock_update_fn);
        INIT_DELAYED_WORK(&kvm->arch.kvmclock_sync_work, kvmclock_sync_fn);

        return 0;
}

static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu)
{
        int r;
        r = vcpu_load(vcpu);
        BUG_ON(r);
        kvm_mmu_unload(vcpu);
        vcpu_put(vcpu);
}

static void kvm_free_vcpus(struct kvm *kvm)
{
        unsigned int i;
        struct kvm_vcpu *vcpu;

        /*
         * Unpin any mmu pages first.
         */
        kvm_for_each_vcpu(i, vcpu, kvm) {
                kvm_clear_async_pf_completion_queue(vcpu);
                kvm_unload_vcpu_mmu(vcpu);
        }
        kvm_for_each_vcpu(i, vcpu, kvm)
                kvm_arch_vcpu_free(vcpu);

        mutex_lock(&kvm->lock);
        for (i = 0; i < atomic_read(&kvm->online_vcpus); i++)
                kvm->vcpus[i] = NULL;

        atomic_set(&kvm->online_vcpus, 0);
        mutex_unlock(&kvm->lock);
}

void kvm_arch_sync_events(struct kvm *kvm)
{
        cancel_delayed_work_sync(&kvm->arch.kvmclock_sync_work);
        cancel_delayed_work_sync(&kvm->arch.kvmclock_update_work);
        kvm_free_all_assigned_devices(kvm);
        kvm_free_pit(kvm);
}

int __x86_set_memory_region(struct kvm *kvm,
                            const struct kvm_userspace_memory_region *mem)
{
        int i, r;

        /* Called with kvm->slots_lock held.  */
        BUG_ON(mem->slot >= KVM_MEM_SLOTS_NUM);

        for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
                struct kvm_userspace_memory_region m = *mem;

                m.slot |= i << 16;
                r = __kvm_set_memory_region(kvm, &m);
                if (r < 0)
                        return r;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(__x86_set_memory_region);

int x86_set_memory_region(struct kvm *kvm,
                          const struct kvm_userspace_memory_region *mem)
{
        int r;

        mutex_lock(&kvm->slots_lock);
        r = __x86_set_memory_region(kvm, mem);
        mutex_unlock(&kvm->slots_lock);

        return r;
}
EXPORT_SYMBOL_GPL(x86_set_memory_region);

void kvm_arch_destroy_vm(struct kvm *kvm)
{
        if (current->mm == kvm->mm) {
                /*
                 * Free memory regions allocated on behalf of userspace,
                 * unless the the memory map has changed due to process exit
                 * or fd copying.
                 */
                struct kvm_userspace_memory_region mem;
                memset(&mem, 0, sizeof(mem));
                mem.slot = APIC_ACCESS_PAGE_PRIVATE_MEMSLOT;
                x86_set_memory_region(kvm, &mem);

                mem.slot = IDENTITY_PAGETABLE_PRIVATE_MEMSLOT;
                x86_set_memory_region(kvm, &mem);

                mem.slot = TSS_PRIVATE_MEMSLOT;
                x86_set_memory_region(kvm, &mem);
        }
        kvm_iommu_unmap_guest(kvm);
        kfree(kvm->arch.vpic);
        kfree(kvm->arch.vioapic);
        kvm_free_vcpus(kvm);
        kfree(rcu_dereference_check(kvm->arch.apic_map, 1));
}

void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free,
                           struct kvm_memory_slot *dont)
{
        int i;

        for (i = 0; i < KVM_NR_PAGE_SIZES; ++i) {
                if (!dont || free->arch.rmap[i] != dont->arch.rmap[i]) {
                        kvfree(free->arch.rmap[i]);
                        free->arch.rmap[i] = NULL;
                }
                if (i == 0)
                        continue;

                if (!dont || free->arch.lpage_info[i - 1] !=
                             dont->arch.lpage_info[i - 1]) {
                        kvfree(free->arch.lpage_info[i - 1]);
                        free->arch.lpage_info[i - 1] = NULL;
                }
        }
}

int kvm_arch_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot,
                            unsigned long npages)
{
        int i;

        for (i = 0; i < KVM_NR_PAGE_SIZES; ++i) {
                unsigned long ugfn;
                int lpages;
                int level = i + 1;

                lpages = gfn_to_index(slot->base_gfn + npages - 1,
                                      slot->base_gfn, level) + 1;

                slot->arch.rmap[i] =
                        kvm_kvzalloc(lpages * sizeof(*slot->arch.rmap[i]));
                if (!slot->arch.rmap[i])
                        goto out_free;
                if (i == 0)
                        continue;

                slot->arch.lpage_info[i - 1] = kvm_kvzalloc(lpages *
                                        sizeof(*slot->arch.lpage_info[i - 1]));
                if (!slot->arch.lpage_info[i - 1])
                        goto out_free;

                if (slot->base_gfn & (KVM_PAGES_PER_HPAGE(level) - 1))
                        slot->arch.lpage_info[i - 1][0].write_count = 1;
                if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1))
                        slot->arch.lpage_info[i - 1][lpages - 1].write_count = 1;
                ugfn = slot->userspace_addr >> PAGE_SHIFT;
                /*
                 * If the gfn and userspace address are not aligned wrt each
                 * other, or if explicitly asked to, disable large page
                 * support for this slot
                 */
                if ((slot->base_gfn ^ ugfn) & (KVM_PAGES_PER_HPAGE(level) - 1) ||
                    !kvm_largepages_enabled()) {
                        unsigned long j;

                        for (j = 0; j < lpages; ++j)
                                slot->arch.lpage_info[i - 1][j].write_count = 1;
                }
        }

        return 0;

out_free:
        for (i = 0; i < KVM_NR_PAGE_SIZES; ++i) {
                kvfree(slot->arch.rmap[i]);
                slot->arch.rmap[i] = NULL;
                if (i == 0)
                        continue;

                kvfree(slot->arch.lpage_info[i - 1]);
                slot->arch.lpage_info[i - 1] = NULL;
        }
        return -ENOMEM;
}

void kvm_arch_memslots_updated(struct kvm *kvm, struct kvm_memslots *slots)
{
        /*
         * memslots->generation has been incremented.
         * mmio generation may have reached its maximum value.
         */
        kvm_mmu_invalidate_mmio_sptes(kvm, slots);
}

int kvm_arch_prepare_memory_region(struct kvm *kvm,
                                struct kvm_memory_slot *memslot,
                                const struct kvm_userspace_memory_region *mem,
                                enum kvm_mr_change change)
{
        /*
         * Only private memory slots need to be mapped here since
         * KVM_SET_MEMORY_REGION ioctl is no longer supported.
         */
        if ((memslot->id >= KVM_USER_MEM_SLOTS) && (change == KVM_MR_CREATE)) {
                unsigned long userspace_addr;

                /*
                 * MAP_SHARED to prevent internal slot pages from being moved
                 * by fork()/COW.
                 */
                userspace_addr = vm_mmap(NULL, 0, memslot->npages * PAGE_SIZE,
                                         PROT_READ | PROT_WRITE,
                                         MAP_SHARED | MAP_ANONYMOUS, 0);

                if (IS_ERR((void *)userspace_addr))
                        return PTR_ERR((void *)userspace_addr);

                memslot->userspace_addr = userspace_addr;
        }

        return 0;
}

static void kvm_mmu_slot_apply_flags(struct kvm *kvm,
                                     struct kvm_memory_slot *new)
{
        /* Still write protect RO slot */
        if (new->flags & KVM_MEM_READONLY) {
                kvm_mmu_slot_remove_write_access(kvm, new);
                return;
        }

        /*
         * Call kvm_x86_ops dirty logging hooks when they are valid.
         *
         * kvm_x86_ops->slot_disable_log_dirty is called when:
         *
         *  - KVM_MR_CREATE with dirty logging is disabled
         *  - KVM_MR_FLAGS_ONLY with dirty logging is disabled in new flag
         *
         * The reason is, in case of PML, we need to set D-bit for any slots
         * with dirty logging disabled in order to eliminate unnecessary GPA
         * logging in PML buffer (and potential PML buffer full VMEXT). This
         * guarantees leaving PML enabled during guest's lifetime won't have
         * any additonal overhead from PML when guest is running with dirty
         * logging disabled for memory slots.
         *
         * kvm_x86_ops->slot_enable_log_dirty is called when switching new slot
         * to dirty logging mode.
         *
         * If kvm_x86_ops dirty logging hooks are invalid, use write protect.
         *
         * In case of write protect:
         *
         * Write protect all pages for dirty logging.
         *
         * All the sptes including the large sptes which point to this
         * slot are set to readonly. We can not create any new large
         * spte on this slot until the end of the logging.
         *
         * See the comments in fast_page_fault().
         */
        if (new->flags & KVM_MEM_LOG_DIRTY_PAGES) {
                if (kvm_x86_ops->slot_enable_log_dirty)
                        kvm_x86_ops->slot_enable_log_dirty(kvm, new);
                else
                        kvm_mmu_slot_remove_write_access(kvm, new);
        } else {
                if (kvm_x86_ops->slot_disable_log_dirty)
                        kvm_x86_ops->slot_disable_log_dirty(kvm, new);
        }
}

void kvm_arch_commit_memory_region(struct kvm *kvm,
                                const struct kvm_userspace_memory_region *mem,
                                const struct kvm_memory_slot *old,
                                const struct kvm_memory_slot *new,
                                enum kvm_mr_change change)
{
        int nr_mmu_pages = 0;

        if (change == KVM_MR_DELETE && old->id >= KVM_USER_MEM_SLOTS) {
                int ret;

                ret = vm_munmap(old->userspace_addr,
                                old->npages * PAGE_SIZE);
                if (ret < 0)
                        printk(KERN_WARNING
                               "kvm_vm_ioctl_set_memory_region: "
                               "failed to munmap memory\n");
        }

        if (!kvm->arch.n_requested_mmu_pages)
                nr_mmu_pages = kvm_mmu_calculate_mmu_pages(kvm);

        if (nr_mmu_pages)
                kvm_mmu_change_mmu_pages(kvm, nr_mmu_pages);

        /*
         * Dirty logging tracks sptes in 4k granularity, meaning that large
         * sptes have to be split.  If live migration is successful, the guest
         * in the source machine will be destroyed and large sptes will be
         * created in the destination. However, if the guest continues to run
         * in the source machine (for example if live migration fails), small
         * sptes will remain around and cause bad performance.
         *
         * Scan sptes if dirty logging has been stopped, dropping those
         * which can be collapsed into a single large-page spte.  Later
         * page faults will create the large-page sptes.
         */
        if ((change != KVM_MR_DELETE) &&
                (old->flags & KVM_MEM_LOG_DIRTY_PAGES) &&
                !(new->flags & KVM_MEM_LOG_DIRTY_PAGES))
                kvm_mmu_zap_collapsible_sptes(kvm, new);

        /*
         * Set up write protection and/or dirty logging for the new slot.
         *
         * For KVM_MR_DELETE and KVM_MR_MOVE, the shadow pages of old slot have
         * been zapped so no dirty logging staff is needed for old slot. For
         * KVM_MR_FLAGS_ONLY, the old slot is essentially the same one as the
         * new and it's also covered when dealing with the new slot.
         *
         * FIXME: const-ify all uses of struct kvm_memory_slot.
         */
        if (change != KVM_MR_DELETE)
                kvm_mmu_slot_apply_flags(kvm, (struct kvm_memory_slot *) new);
}

void kvm_arch_flush_shadow_all(struct kvm *kvm)
{
        kvm_mmu_invalidate_zap_all_pages(kvm);
}

void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
                                   struct kvm_memory_slot *slot)
{
        kvm_mmu_invalidate_zap_all_pages(kvm);
}

int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
{
        if (is_guest_mode(vcpu) && kvm_x86_ops->check_nested_events)
                kvm_x86_ops->check_nested_events(vcpu, false);

        return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE &&
                !vcpu->arch.apf.halted)
                || !list_empty_careful(&vcpu->async_pf.done)
                || kvm_apic_has_events(vcpu)
                || vcpu->arch.pv.pv_unhalted
                || atomic_read(&vcpu->arch.nmi_queued) ||
                (kvm_arch_interrupt_allowed(vcpu) &&
                 kvm_cpu_has_interrupt(vcpu));
}

int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
{
        return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
}

int kvm_arch_interrupt_allowed(struct kvm_vcpu *vcpu)
{
        return kvm_x86_ops->interrupt_allowed(vcpu);
}

unsigned long kvm_get_linear_rip(struct kvm_vcpu *vcpu)
{
        if (is_64_bit_mode(vcpu))
                return kvm_rip_read(vcpu);
        return (u32)(get_segment_base(vcpu, VCPU_SREG_CS) +
                     kvm_rip_read(vcpu));
}
EXPORT_SYMBOL_GPL(kvm_get_linear_rip);

bool kvm_is_linear_rip(struct kvm_vcpu *vcpu, unsigned long linear_rip)
{
        return kvm_get_linear_rip(vcpu) == linear_rip;
}
EXPORT_SYMBOL_GPL(kvm_is_linear_rip);

unsigned long kvm_get_rflags(struct kvm_vcpu *vcpu)
{
        unsigned long rflags;

        rflags = kvm_x86_ops->get_rflags(vcpu);
        if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
                rflags &= ~X86_EFLAGS_TF;
        return rflags;
}
EXPORT_SYMBOL_GPL(kvm_get_rflags);

static void __kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
{
        if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP &&
            kvm_is_linear_rip(vcpu, vcpu->arch.singlestep_rip))
                rflags |= X86_EFLAGS_TF;
        kvm_x86_ops->set_rflags(vcpu, rflags);
}

void kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
{
        __kvm_set_rflags(vcpu, rflags);
        kvm_make_request(KVM_REQ_EVENT, vcpu);
}
EXPORT_SYMBOL_GPL(kvm_set_rflags);

void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
{
        int r;

        if ((vcpu->arch.mmu.direct_map != work->arch.direct_map) ||
              work->wakeup_all)
                return;

        r = kvm_mmu_reload(vcpu);
        if (unlikely(r))
                return;

        if (!vcpu->arch.mmu.direct_map &&
              work->arch.cr3 != vcpu->arch.mmu.get_cr3(vcpu))
                return;

        vcpu->arch.mmu.page_fault(vcpu, work->gva, 0, true);
}

static inline u32 kvm_async_pf_hash_fn(gfn_t gfn)
{
        return hash_32(gfn & 0xffffffff, order_base_2(ASYNC_PF_PER_VCPU));
}

static inline u32 kvm_async_pf_next_probe(u32 key)
{
        return (key + 1) & (roundup_pow_of_two(ASYNC_PF_PER_VCPU) - 1);
}

static void kvm_add_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
{
        u32 key = kvm_async_pf_hash_fn(gfn);

        while (vcpu->arch.apf.gfns[key] != ~0)
                key = kvm_async_pf_next_probe(key);

        vcpu->arch.apf.gfns[key] = gfn;
}

static u32 kvm_async_pf_gfn_slot(struct kvm_vcpu *vcpu, gfn_t gfn)
{
        int i;
        u32 key = kvm_async_pf_hash_fn(gfn);

        for (i = 0; i < roundup_pow_of_two(ASYNC_PF_PER_VCPU) &&
                     (vcpu->arch.apf.gfns[key] != gfn &&
                      vcpu->arch.apf.gfns[key] != ~0); i++)
                key = kvm_async_pf_next_probe(key);

        return key;
}

bool kvm_find_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
{
        return vcpu->arch.apf.gfns[kvm_async_pf_gfn_slot(vcpu, gfn)] == gfn;
}

static void kvm_del_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
{
        u32 i, j, k;

        i = j = kvm_async_pf_gfn_slot(vcpu, gfn);
        while (true) {
                vcpu->arch.apf.gfns[i] = ~0;
                do {
                        j = kvm_async_pf_next_probe(j);
                        if (vcpu->arch.apf.gfns[j] == ~0)
                                return;
                        k = kvm_async_pf_hash_fn(vcpu->arch.apf.gfns[j]);
                        /*
                         * k lies cyclically in ]i,j]
                         * |    i.k.j |
                         * |....j i.k.| or  |.k..j i...|
                         */
                } while ((i <= j) ? (i < k && k <= j) : (i < k || k <= j));
                vcpu->arch.apf.gfns[i] = vcpu->arch.apf.gfns[j];
                i = j;
        }
}

static int apf_put_user(struct kvm_vcpu *vcpu, u32 val)
{

        return kvm_write_guest_cached(vcpu->kvm, &vcpu->arch.apf.data, &val,
                                      sizeof(val));
}

void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu,
                                     struct kvm_async_pf *work)
{
        struct x86_exception fault;

        trace_kvm_async_pf_not_present(work->arch.token, work->gva);
        kvm_add_async_pf_gfn(vcpu, work->arch.gfn);

        if (!(vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED) ||
            (vcpu->arch.apf.send_user_only &&
             kvm_x86_ops->get_cpl(vcpu) == 0))
                kvm_make_request(KVM_REQ_APF_HALT, vcpu);
        else if (!apf_put_user(vcpu, KVM_PV_REASON_PAGE_NOT_PRESENT)) {
                fault.vector = PF_VECTOR;
                fault.error_code_valid = true;
                fault.error_code = 0;
                fault.nested_page_fault = false;
                fault.address = work->arch.token;
                kvm_inject_page_fault(vcpu, &fault);
        }
}

void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
                                 struct kvm_async_pf *work)
{
        struct x86_exception fault;

        trace_kvm_async_pf_ready(work->arch.token, work->gva);
        if (work->wakeup_all)
                work->arch.token = ~0; /* broadcast wakeup */
        else
                kvm_del_async_pf_gfn(vcpu, work->arch.gfn);

        if ((vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED) &&
            !apf_put_user(vcpu, KVM_PV_REASON_PAGE_READY)) {
                fault.vector = PF_VECTOR;
                fault.error_code_valid = true;
                fault.error_code = 0;
                fault.nested_page_fault = false;
                fault.address = work->arch.token;
                kvm_inject_page_fault(vcpu, &fault);
        }
        vcpu->arch.apf.halted = false;
        vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
}

bool kvm_arch_can_inject_async_page_present(struct kvm_vcpu *vcpu)
{
        if (!(vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED))
                return true;
        else
                return !kvm_event_needs_reinjection(vcpu) &&
                        kvm_x86_ops->interrupt_allowed(vcpu);
}

void kvm_arch_start_assignment(struct kvm *kvm)
{
        atomic_inc(&kvm->arch.assigned_device_count);
}
EXPORT_SYMBOL_GPL(kvm_arch_start_assignment);

void kvm_arch_end_assignment(struct kvm *kvm)
{
        atomic_dec(&kvm->arch.assigned_device_count);
}
EXPORT_SYMBOL_GPL(kvm_arch_end_assignment);

bool kvm_arch_has_assigned_device(struct kvm *kvm)
{
        return atomic_read(&kvm->arch.assigned_device_count);
}
EXPORT_SYMBOL_GPL(kvm_arch_has_assigned_device);

void kvm_arch_register_noncoherent_dma(struct kvm *kvm)
{
        atomic_inc(&kvm->arch.noncoherent_dma_count);
}
EXPORT_SYMBOL_GPL(kvm_arch_register_noncoherent_dma);

void kvm_arch_unregister_noncoherent_dma(struct kvm *kvm)
{
        atomic_dec(&kvm->arch.noncoherent_dma_count);
}
EXPORT_SYMBOL_GPL(kvm_arch_unregister_noncoherent_dma);

bool kvm_arch_has_noncoherent_dma(struct kvm *kvm)
{
        return atomic_read(&kvm->arch.noncoherent_dma_count);
}
EXPORT_SYMBOL_GPL(kvm_arch_has_noncoherent_dma);

EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_page_fault);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_msr);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_cr);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_vmrun);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_vmexit);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_vmexit_inject);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_intr_vmexit);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_invlpga);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_skinit);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_intercepts);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_write_tsc_offset);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_ple_window);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_pml_full);