KVM: vgic: declare probe function pointer as const

[deliverable/linux.git] / virt / kvm / arm / vgic.c

/*
 * Copyright (C) 2012 ARM Ltd.
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/cpu.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/uaccess.h>

#include <linux/irqchip/arm-gic.h>

#include <asm/kvm_emulate.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_mmu.h>

/*
 * How the whole thing works (courtesy of Christoffer Dall):
 *
 * - At any time, the dist->irq_pending_on_cpu is the oracle that knows if
 *   something is pending
 * - VGIC pending interrupts are stored on the vgic.irq_state vgic
 *   bitmap (this bitmap is updated by both user land ioctls and guest
 *   mmio ops, and other in-kernel peripherals such as the
 *   arch. timers) and indicate the 'wire' state.
 * - Every time the bitmap changes, the irq_pending_on_cpu oracle is
 *   recalculated
 * - To calculate the oracle, we need info for each cpu from
 *   compute_pending_for_cpu, which considers:
 *   - PPI: dist->irq_state & dist->irq_enable
 *   - SPI: dist->irq_state & dist->irq_enable & dist->irq_spi_target
 *   - irq_spi_target is a 'formatted' version of the GICD_ICFGR
 *     registers, stored on each vcpu. We only keep one bit of
 *     information per interrupt, making sure that only one vcpu can
 *     accept the interrupt.
 * - The same is true when injecting an interrupt, except that we only
 *   consider a single interrupt at a time. The irq_spi_cpu array
 *   contains the target CPU for each SPI.
 *
 * The handling of level interrupts adds some extra complexity. We
 * need to track when the interrupt has been EOIed, so we can sample
 * the 'line' again. This is achieved as such:
 *
 * - When a level interrupt is moved onto a vcpu, the corresponding
 *   bit in irq_active is set. As long as this bit is set, the line
 *   will be ignored for further interrupts. The interrupt is injected
 *   into the vcpu with the GICH_LR_EOI bit set (generate a
 *   maintenance interrupt on EOI).
 * - When the interrupt is EOIed, the maintenance interrupt fires,
 *   and clears the corresponding bit in irq_active. This allow the
 *   interrupt line to be sampled again.
 */

#define VGIC_ADDR_UNDEF         (-1)
#define IS_VGIC_ADDR_UNDEF(_x)  ((_x) == VGIC_ADDR_UNDEF)

#define PRODUCT_ID_KVM          0x4b    /* ASCII code K */
#define IMPLEMENTER_ARM         0x43b
#define GICC_ARCH_VERSION_V2    0x2

#define ACCESS_READ_VALUE       (1 << 0)
#define ACCESS_READ_RAZ         (0 << 0)
#define ACCESS_READ_MASK(x)     ((x) & (1 << 0))
#define ACCESS_WRITE_IGNORED    (0 << 1)
#define ACCESS_WRITE_SETBIT     (1 << 1)
#define ACCESS_WRITE_CLEARBIT   (2 << 1)
#define ACCESS_WRITE_VALUE      (3 << 1)
#define ACCESS_WRITE_MASK(x)    ((x) & (3 << 1))

static void vgic_retire_disabled_irqs(struct kvm_vcpu *vcpu);
static void vgic_retire_lr(int lr_nr, int irq, struct kvm_vcpu *vcpu);
static void vgic_update_state(struct kvm *kvm);
static void vgic_kick_vcpus(struct kvm *kvm);
static void vgic_dispatch_sgi(struct kvm_vcpu *vcpu, u32 reg);
static struct vgic_lr vgic_get_lr(const struct kvm_vcpu *vcpu, int lr);
static void vgic_set_lr(struct kvm_vcpu *vcpu, int lr, struct vgic_lr lr_desc);
static void vgic_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
static void vgic_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);

static const struct vgic_ops *vgic_ops;
static const struct vgic_params *vgic;

/*
 * struct vgic_bitmap contains unions that provide two views of
 * the same data. In one case it is an array of registers of
 * u32's, and in the other case it is a bitmap of unsigned
 * longs.
 *
 * This does not work on 64-bit BE systems, because the bitmap access
 * will store two consecutive 32-bit words with the higher-addressed
 * register's bits at the lower index and the lower-addressed register's
 * bits at the higher index.
 *
 * Therefore, swizzle the register index when accessing the 32-bit word
 * registers to access the right register's value.
 */
#if defined(CONFIG_CPU_BIG_ENDIAN) && BITS_PER_LONG == 64
#define REG_OFFSET_SWIZZLE      1
#else
#define REG_OFFSET_SWIZZLE      0
#endif

static u32 *vgic_bitmap_get_reg(struct vgic_bitmap *x,
                                int cpuid, u32 offset)
{
        offset >>= 2;
        if (!offset)
                return x->percpu[cpuid].reg + (offset ^ REG_OFFSET_SWIZZLE);
        else
                return x->shared.reg + ((offset - 1) ^ REG_OFFSET_SWIZZLE);
}

static int vgic_bitmap_get_irq_val(struct vgic_bitmap *x,
                                   int cpuid, int irq)
{
        if (irq < VGIC_NR_PRIVATE_IRQS)
                return test_bit(irq, x->percpu[cpuid].reg_ul);

        return test_bit(irq - VGIC_NR_PRIVATE_IRQS, x->shared.reg_ul);
}

static void vgic_bitmap_set_irq_val(struct vgic_bitmap *x, int cpuid,
                                    int irq, int val)
{
        unsigned long *reg;

        if (irq < VGIC_NR_PRIVATE_IRQS) {
                reg = x->percpu[cpuid].reg_ul;
        } else {
                reg =  x->shared.reg_ul;
                irq -= VGIC_NR_PRIVATE_IRQS;
        }

        if (val)
                set_bit(irq, reg);
        else
                clear_bit(irq, reg);
}

static unsigned long *vgic_bitmap_get_cpu_map(struct vgic_bitmap *x, int cpuid)
{
        if (unlikely(cpuid >= VGIC_MAX_CPUS))
                return NULL;
        return x->percpu[cpuid].reg_ul;
}

static unsigned long *vgic_bitmap_get_shared_map(struct vgic_bitmap *x)
{
        return x->shared.reg_ul;
}

static u32 *vgic_bytemap_get_reg(struct vgic_bytemap *x, int cpuid, u32 offset)
{
        offset >>= 2;
        BUG_ON(offset > (VGIC_NR_IRQS / 4));
        if (offset < 8)
                return x->percpu[cpuid] + offset;
        else
                return x->shared + offset - 8;
}

#define VGIC_CFG_LEVEL  0
#define VGIC_CFG_EDGE   1

static bool vgic_irq_is_edge(struct kvm_vcpu *vcpu, int irq)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
        int irq_val;

        irq_val = vgic_bitmap_get_irq_val(&dist->irq_cfg, vcpu->vcpu_id, irq);
        return irq_val == VGIC_CFG_EDGE;
}

static int vgic_irq_is_enabled(struct kvm_vcpu *vcpu, int irq)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

        return vgic_bitmap_get_irq_val(&dist->irq_enabled, vcpu->vcpu_id, irq);
}

static int vgic_irq_is_active(struct kvm_vcpu *vcpu, int irq)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

        return vgic_bitmap_get_irq_val(&dist->irq_active, vcpu->vcpu_id, irq);
}

static void vgic_irq_set_active(struct kvm_vcpu *vcpu, int irq)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

        vgic_bitmap_set_irq_val(&dist->irq_active, vcpu->vcpu_id, irq, 1);
}

static void vgic_irq_clear_active(struct kvm_vcpu *vcpu, int irq)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

        vgic_bitmap_set_irq_val(&dist->irq_active, vcpu->vcpu_id, irq, 0);
}

static int vgic_dist_irq_is_pending(struct kvm_vcpu *vcpu, int irq)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

        return vgic_bitmap_get_irq_val(&dist->irq_state, vcpu->vcpu_id, irq);
}

static void vgic_dist_irq_set(struct kvm_vcpu *vcpu, int irq)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

        vgic_bitmap_set_irq_val(&dist->irq_state, vcpu->vcpu_id, irq, 1);
}

static void vgic_dist_irq_clear(struct kvm_vcpu *vcpu, int irq)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

        vgic_bitmap_set_irq_val(&dist->irq_state, vcpu->vcpu_id, irq, 0);
}

static void vgic_cpu_irq_set(struct kvm_vcpu *vcpu, int irq)
{
        if (irq < VGIC_NR_PRIVATE_IRQS)
                set_bit(irq, vcpu->arch.vgic_cpu.pending_percpu);
        else
                set_bit(irq - VGIC_NR_PRIVATE_IRQS,
                        vcpu->arch.vgic_cpu.pending_shared);
}

static void vgic_cpu_irq_clear(struct kvm_vcpu *vcpu, int irq)
{
        if (irq < VGIC_NR_PRIVATE_IRQS)
                clear_bit(irq, vcpu->arch.vgic_cpu.pending_percpu);
        else
                clear_bit(irq - VGIC_NR_PRIVATE_IRQS,
                          vcpu->arch.vgic_cpu.pending_shared);
}

static u32 mmio_data_read(struct kvm_exit_mmio *mmio, u32 mask)
{
        return le32_to_cpu(*((u32 *)mmio->data)) & mask;
}

static void mmio_data_write(struct kvm_exit_mmio *mmio, u32 mask, u32 value)
{
        *((u32 *)mmio->data) = cpu_to_le32(value) & mask;
}

/**
 * vgic_reg_access - access vgic register
 * @mmio:   pointer to the data describing the mmio access
 * @reg:    pointer to the virtual backing of vgic distributor data
 * @offset: least significant 2 bits used for word offset
 * @mode:   ACCESS_ mode (see defines above)
 *
 * Helper to make vgic register access easier using one of the access
 * modes defined for vgic register access
 * (read,raz,write-ignored,setbit,clearbit,write)
 */
static void vgic_reg_access(struct kvm_exit_mmio *mmio, u32 *reg,
                            phys_addr_t offset, int mode)
{
        int word_offset = (offset & 3) * 8;
        u32 mask = (1UL << (mmio->len * 8)) - 1;
        u32 regval;

        /*
         * Any alignment fault should have been delivered to the guest
         * directly (ARM ARM B3.12.7 "Prioritization of aborts").
         */

        if (reg) {
                regval = *reg;
        } else {
                BUG_ON(mode != (ACCESS_READ_RAZ | ACCESS_WRITE_IGNORED));
                regval = 0;
        }

        if (mmio->is_write) {
                u32 data = mmio_data_read(mmio, mask) << word_offset;
                switch (ACCESS_WRITE_MASK(mode)) {
                case ACCESS_WRITE_IGNORED:
                        return;

                case ACCESS_WRITE_SETBIT:
                        regval |= data;
                        break;

                case ACCESS_WRITE_CLEARBIT:
                        regval &= ~data;
                        break;

                case ACCESS_WRITE_VALUE:
                        regval = (regval & ~(mask << word_offset)) | data;
                        break;
                }
                *reg = regval;
        } else {
                switch (ACCESS_READ_MASK(mode)) {
                case ACCESS_READ_RAZ:
                        regval = 0;
                        /* fall through */

                case ACCESS_READ_VALUE:
                        mmio_data_write(mmio, mask, regval >> word_offset);
                }
        }
}

static bool handle_mmio_misc(struct kvm_vcpu *vcpu,
                             struct kvm_exit_mmio *mmio, phys_addr_t offset)
{
        u32 reg;
        u32 word_offset = offset & 3;

        switch (offset & ~3) {
        case 0:                 /* GICD_CTLR */
                reg = vcpu->kvm->arch.vgic.enabled;
                vgic_reg_access(mmio, &reg, word_offset,
                                ACCESS_READ_VALUE | ACCESS_WRITE_VALUE);
                if (mmio->is_write) {
                        vcpu->kvm->arch.vgic.enabled = reg & 1;
                        vgic_update_state(vcpu->kvm);
                        return true;
                }
                break;

        case 4:                 /* GICD_TYPER */
                reg  = (atomic_read(&vcpu->kvm->online_vcpus) - 1) << 5;
                reg |= (VGIC_NR_IRQS >> 5) - 1;
                vgic_reg_access(mmio, &reg, word_offset,
                                ACCESS_READ_VALUE | ACCESS_WRITE_IGNORED);
                break;

        case 8:                 /* GICD_IIDR */
                reg = (PRODUCT_ID_KVM << 24) | (IMPLEMENTER_ARM << 0);
                vgic_reg_access(mmio, &reg, word_offset,
                                ACCESS_READ_VALUE | ACCESS_WRITE_IGNORED);
                break;
        }

        return false;
}

static bool handle_mmio_raz_wi(struct kvm_vcpu *vcpu,
                               struct kvm_exit_mmio *mmio, phys_addr_t offset)
{
        vgic_reg_access(mmio, NULL, offset,
                        ACCESS_READ_RAZ | ACCESS_WRITE_IGNORED);
        return false;
}

static bool handle_mmio_set_enable_reg(struct kvm_vcpu *vcpu,
                                       struct kvm_exit_mmio *mmio,
                                       phys_addr_t offset)
{
        u32 *reg = vgic_bitmap_get_reg(&vcpu->kvm->arch.vgic.irq_enabled,
                                       vcpu->vcpu_id, offset);
        vgic_reg_access(mmio, reg, offset,
                        ACCESS_READ_VALUE | ACCESS_WRITE_SETBIT);
        if (mmio->is_write) {
                vgic_update_state(vcpu->kvm);
                return true;
        }

        return false;
}

static bool handle_mmio_clear_enable_reg(struct kvm_vcpu *vcpu,
                                         struct kvm_exit_mmio *mmio,
                                         phys_addr_t offset)
{
        u32 *reg = vgic_bitmap_get_reg(&vcpu->kvm->arch.vgic.irq_enabled,
                                       vcpu->vcpu_id, offset);
        vgic_reg_access(mmio, reg, offset,
                        ACCESS_READ_VALUE | ACCESS_WRITE_CLEARBIT);
        if (mmio->is_write) {
                if (offset < 4) /* Force SGI enabled */
                        *reg |= 0xffff;
                vgic_retire_disabled_irqs(vcpu);
                vgic_update_state(vcpu->kvm);
                return true;
        }

        return false;
}

static bool handle_mmio_set_pending_reg(struct kvm_vcpu *vcpu,
                                        struct kvm_exit_mmio *mmio,
                                        phys_addr_t offset)
{
        u32 *reg = vgic_bitmap_get_reg(&vcpu->kvm->arch.vgic.irq_state,
                                       vcpu->vcpu_id, offset);
        vgic_reg_access(mmio, reg, offset,
                        ACCESS_READ_VALUE | ACCESS_WRITE_SETBIT);
        if (mmio->is_write) {
                vgic_update_state(vcpu->kvm);
                return true;
        }

        return false;
}

static bool handle_mmio_clear_pending_reg(struct kvm_vcpu *vcpu,
                                          struct kvm_exit_mmio *mmio,
                                          phys_addr_t offset)
{
        u32 *reg = vgic_bitmap_get_reg(&vcpu->kvm->arch.vgic.irq_state,
                                       vcpu->vcpu_id, offset);
        vgic_reg_access(mmio, reg, offset,
                        ACCESS_READ_VALUE | ACCESS_WRITE_CLEARBIT);
        if (mmio->is_write) {
                vgic_update_state(vcpu->kvm);
                return true;
        }

        return false;
}

static bool handle_mmio_priority_reg(struct kvm_vcpu *vcpu,
                                     struct kvm_exit_mmio *mmio,
                                     phys_addr_t offset)
{
        u32 *reg = vgic_bytemap_get_reg(&vcpu->kvm->arch.vgic.irq_priority,
                                        vcpu->vcpu_id, offset);
        vgic_reg_access(mmio, reg, offset,
                        ACCESS_READ_VALUE | ACCESS_WRITE_VALUE);
        return false;
}

#define GICD_ITARGETSR_SIZE     32
#define GICD_CPUTARGETS_BITS    8
#define GICD_IRQS_PER_ITARGETSR (GICD_ITARGETSR_SIZE / GICD_CPUTARGETS_BITS)
static u32 vgic_get_target_reg(struct kvm *kvm, int irq)
{
        struct vgic_dist *dist = &kvm->arch.vgic;
        int i;
        u32 val = 0;

        irq -= VGIC_NR_PRIVATE_IRQS;

        for (i = 0; i < GICD_IRQS_PER_ITARGETSR; i++)
                val |= 1 << (dist->irq_spi_cpu[irq + i] + i * 8);

        return val;
}

static void vgic_set_target_reg(struct kvm *kvm, u32 val, int irq)
{
        struct vgic_dist *dist = &kvm->arch.vgic;
        struct kvm_vcpu *vcpu;
        int i, c;
        unsigned long *bmap;
        u32 target;

        irq -= VGIC_NR_PRIVATE_IRQS;

        /*
         * Pick the LSB in each byte. This ensures we target exactly
         * one vcpu per IRQ. If the byte is null, assume we target
         * CPU0.
         */
        for (i = 0; i < GICD_IRQS_PER_ITARGETSR; i++) {
                int shift = i * GICD_CPUTARGETS_BITS;
                target = ffs((val >> shift) & 0xffU);
                target = target ? (target - 1) : 0;
                dist->irq_spi_cpu[irq + i] = target;
                kvm_for_each_vcpu(c, vcpu, kvm) {
                        bmap = vgic_bitmap_get_shared_map(&dist->irq_spi_target[c]);
                        if (c == target)
                                set_bit(irq + i, bmap);
                        else
                                clear_bit(irq + i, bmap);
                }
        }
}

static bool handle_mmio_target_reg(struct kvm_vcpu *vcpu,
                                   struct kvm_exit_mmio *mmio,
                                   phys_addr_t offset)
{
        u32 reg;

        /* We treat the banked interrupts targets as read-only */
        if (offset < 32) {
                u32 roreg = 1 << vcpu->vcpu_id;
                roreg |= roreg << 8;
                roreg |= roreg << 16;

                vgic_reg_access(mmio, &roreg, offset,
                                ACCESS_READ_VALUE | ACCESS_WRITE_IGNORED);
                return false;
        }

        reg = vgic_get_target_reg(vcpu->kvm, offset & ~3U);
        vgic_reg_access(mmio, &reg, offset,
                        ACCESS_READ_VALUE | ACCESS_WRITE_VALUE);
        if (mmio->is_write) {
                vgic_set_target_reg(vcpu->kvm, reg, offset & ~3U);
                vgic_update_state(vcpu->kvm);
                return true;
        }

        return false;
}

static u32 vgic_cfg_expand(u16 val)
{
        u32 res = 0;
        int i;

        /*
         * Turn a 16bit value like abcd...mnop into a 32bit word
         * a0b0c0d0...m0n0o0p0, which is what the HW cfg register is.
         */
        for (i = 0; i < 16; i++)
                res |= ((val >> i) & VGIC_CFG_EDGE) << (2 * i + 1);

        return res;
}

static u16 vgic_cfg_compress(u32 val)
{
        u16 res = 0;
        int i;

        /*
         * Turn a 32bit word a0b0c0d0...m0n0o0p0 into 16bit value like
         * abcd...mnop which is what we really care about.
         */
        for (i = 0; i < 16; i++)
                res |= ((val >> (i * 2 + 1)) & VGIC_CFG_EDGE) << i;

        return res;
}

/*
 * The distributor uses 2 bits per IRQ for the CFG register, but the
 * LSB is always 0. As such, we only keep the upper bit, and use the
 * two above functions to compress/expand the bits
 */
static bool handle_mmio_cfg_reg(struct kvm_vcpu *vcpu,
                                struct kvm_exit_mmio *mmio, phys_addr_t offset)
{
        u32 val;
        u32 *reg;

        reg = vgic_bitmap_get_reg(&vcpu->kvm->arch.vgic.irq_cfg,
                                  vcpu->vcpu_id, offset >> 1);

        if (offset & 4)
                val = *reg >> 16;
        else
                val = *reg & 0xffff;

        val = vgic_cfg_expand(val);
        vgic_reg_access(mmio, &val, offset,
                        ACCESS_READ_VALUE | ACCESS_WRITE_VALUE);
        if (mmio->is_write) {
                if (offset < 8) {
                        *reg = ~0U; /* Force PPIs/SGIs to 1 */
                        return false;
                }

                val = vgic_cfg_compress(val);
                if (offset & 4) {
                        *reg &= 0xffff;
                        *reg |= val << 16;
                } else {
                        *reg &= 0xffff << 16;
                        *reg |= val;
                }
        }

        return false;
}

static bool handle_mmio_sgi_reg(struct kvm_vcpu *vcpu,
                                struct kvm_exit_mmio *mmio, phys_addr_t offset)
{
        u32 reg;
        vgic_reg_access(mmio, &reg, offset,
                        ACCESS_READ_RAZ | ACCESS_WRITE_VALUE);
        if (mmio->is_write) {
                vgic_dispatch_sgi(vcpu, reg);
                vgic_update_state(vcpu->kvm);
                return true;
        }

        return false;
}

/**
 * vgic_unqueue_irqs - move pending IRQs from LRs to the distributor
 * @vgic_cpu: Pointer to the vgic_cpu struct holding the LRs
 *
 * Move any pending IRQs that have already been assigned to LRs back to the
 * emulated distributor state so that the complete emulated state can be read
 * from the main emulation structures without investigating the LRs.
 *
 * Note that IRQs in the active state in the LRs get their pending state moved
 * to the distributor but the active state stays in the LRs, because we don't
 * track the active state on the distributor side.
 */
static void vgic_unqueue_irqs(struct kvm_vcpu *vcpu)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
        int vcpu_id = vcpu->vcpu_id;
        int i;

        for_each_set_bit(i, vgic_cpu->lr_used, vgic_cpu->nr_lr) {
                struct vgic_lr lr = vgic_get_lr(vcpu, i);

                /*
                 * There are three options for the state bits:
                 *
                 * 01: pending
                 * 10: active
                 * 11: pending and active
                 *
                 * If the LR holds only an active interrupt (not pending) then
                 * just leave it alone.
                 */
                if ((lr.state & LR_STATE_MASK) == LR_STATE_ACTIVE)
                        continue;

                /*
                 * Reestablish the pending state on the distributor and the
                 * CPU interface.  It may have already been pending, but that
                 * is fine, then we are only setting a few bits that were
                 * already set.
                 */
                vgic_dist_irq_set(vcpu, lr.irq);
                if (lr.irq < VGIC_NR_SGIS)
                        dist->irq_sgi_sources[vcpu_id][lr.irq] |= 1 << lr.source;
                lr.state &= ~LR_STATE_PENDING;
                vgic_set_lr(vcpu, i, lr);

                /*
                 * If there's no state left on the LR (it could still be
                 * active), then the LR does not hold any useful info and can
                 * be marked as free for other use.
                 */
                if (!(lr.state & LR_STATE_MASK))
                        vgic_retire_lr(i, lr.irq, vcpu);

                /* Finally update the VGIC state. */
                vgic_update_state(vcpu->kvm);
        }
}

/* Handle reads of GICD_CPENDSGIRn and GICD_SPENDSGIRn */
static bool read_set_clear_sgi_pend_reg(struct kvm_vcpu *vcpu,
                                        struct kvm_exit_mmio *mmio,
                                        phys_addr_t offset)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
        int sgi;
        int min_sgi = (offset & ~0x3) * 4;
        int max_sgi = min_sgi + 3;
        int vcpu_id = vcpu->vcpu_id;
        u32 reg = 0;

        /* Copy source SGIs from distributor side */
        for (sgi = min_sgi; sgi <= max_sgi; sgi++) {
                int shift = 8 * (sgi - min_sgi);
                reg |= (u32)dist->irq_sgi_sources[vcpu_id][sgi] << shift;
        }

        mmio_data_write(mmio, ~0, reg);
        return false;
}

static bool write_set_clear_sgi_pend_reg(struct kvm_vcpu *vcpu,
                                         struct kvm_exit_mmio *mmio,
                                         phys_addr_t offset, bool set)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
        int sgi;
        int min_sgi = (offset & ~0x3) * 4;
        int max_sgi = min_sgi + 3;
        int vcpu_id = vcpu->vcpu_id;
        u32 reg;
        bool updated = false;

        reg = mmio_data_read(mmio, ~0);

        /* Clear pending SGIs on the distributor */
        for (sgi = min_sgi; sgi <= max_sgi; sgi++) {
                u8 mask = reg >> (8 * (sgi - min_sgi));
                if (set) {
                        if ((dist->irq_sgi_sources[vcpu_id][sgi] & mask) != mask)
                                updated = true;
                        dist->irq_sgi_sources[vcpu_id][sgi] |= mask;
                } else {
                        if (dist->irq_sgi_sources[vcpu_id][sgi] & mask)
                                updated = true;
                        dist->irq_sgi_sources[vcpu_id][sgi] &= ~mask;
                }
        }

        if (updated)
                vgic_update_state(vcpu->kvm);

        return updated;
}

static bool handle_mmio_sgi_set(struct kvm_vcpu *vcpu,
                                struct kvm_exit_mmio *mmio,
                                phys_addr_t offset)
{
        if (!mmio->is_write)
                return read_set_clear_sgi_pend_reg(vcpu, mmio, offset);
        else
                return write_set_clear_sgi_pend_reg(vcpu, mmio, offset, true);
}

static bool handle_mmio_sgi_clear(struct kvm_vcpu *vcpu,
                                  struct kvm_exit_mmio *mmio,
                                  phys_addr_t offset)
{
        if (!mmio->is_write)
                return read_set_clear_sgi_pend_reg(vcpu, mmio, offset);
        else
                return write_set_clear_sgi_pend_reg(vcpu, mmio, offset, false);
}

/*
 * I would have liked to use the kvm_bus_io_*() API instead, but it
 * cannot cope with banked registers (only the VM pointer is passed
 * around, and we need the vcpu). One of these days, someone please
 * fix it!
 */
struct mmio_range {
        phys_addr_t base;
        unsigned long len;
        bool (*handle_mmio)(struct kvm_vcpu *vcpu, struct kvm_exit_mmio *mmio,
                            phys_addr_t offset);
};

static const struct mmio_range vgic_dist_ranges[] = {
        {
                .base           = GIC_DIST_CTRL,
                .len            = 12,
                .handle_mmio    = handle_mmio_misc,
        },
        {
                .base           = GIC_DIST_IGROUP,
                .len            = VGIC_NR_IRQS / 8,
                .handle_mmio    = handle_mmio_raz_wi,
        },
        {
                .base           = GIC_DIST_ENABLE_SET,
                .len            = VGIC_NR_IRQS / 8,
                .handle_mmio    = handle_mmio_set_enable_reg,
        },
        {
                .base           = GIC_DIST_ENABLE_CLEAR,
                .len            = VGIC_NR_IRQS / 8,
                .handle_mmio    = handle_mmio_clear_enable_reg,
        },
        {
                .base           = GIC_DIST_PENDING_SET,
                .len            = VGIC_NR_IRQS / 8,
                .handle_mmio    = handle_mmio_set_pending_reg,
        },
        {
                .base           = GIC_DIST_PENDING_CLEAR,
                .len            = VGIC_NR_IRQS / 8,
                .handle_mmio    = handle_mmio_clear_pending_reg,
        },
        {
                .base           = GIC_DIST_ACTIVE_SET,
                .len            = VGIC_NR_IRQS / 8,
                .handle_mmio    = handle_mmio_raz_wi,
        },
        {
                .base           = GIC_DIST_ACTIVE_CLEAR,
                .len            = VGIC_NR_IRQS / 8,
                .handle_mmio    = handle_mmio_raz_wi,
        },
        {
                .base           = GIC_DIST_PRI,
                .len            = VGIC_NR_IRQS,
                .handle_mmio    = handle_mmio_priority_reg,
        },
        {
                .base           = GIC_DIST_TARGET,
                .len            = VGIC_NR_IRQS,
                .handle_mmio    = handle_mmio_target_reg,
        },
        {
                .base           = GIC_DIST_CONFIG,
                .len            = VGIC_NR_IRQS / 4,
                .handle_mmio    = handle_mmio_cfg_reg,
        },
        {
                .base           = GIC_DIST_SOFTINT,
                .len            = 4,
                .handle_mmio    = handle_mmio_sgi_reg,
        },
        {
                .base           = GIC_DIST_SGI_PENDING_CLEAR,
                .len            = VGIC_NR_SGIS,
                .handle_mmio    = handle_mmio_sgi_clear,
        },
        {
                .base           = GIC_DIST_SGI_PENDING_SET,
                .len            = VGIC_NR_SGIS,
                .handle_mmio    = handle_mmio_sgi_set,
        },
        {}
};

static const
struct mmio_range *find_matching_range(const struct mmio_range *ranges,
                                       struct kvm_exit_mmio *mmio,
                                       phys_addr_t offset)
{
        const struct mmio_range *r = ranges;

        while (r->len) {
                if (offset >= r->base &&
                    (offset + mmio->len) <= (r->base + r->len))
                        return r;
                r++;
        }

        return NULL;
}

/**
 * vgic_handle_mmio - handle an in-kernel MMIO access
 * @vcpu:       pointer to the vcpu performing the access
 * @run:        pointer to the kvm_run structure
 * @mmio:       pointer to the data describing the access
 *
 * returns true if the MMIO access has been performed in kernel space,
 * and false if it needs to be emulated in user space.
 */
bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
                      struct kvm_exit_mmio *mmio)
{
        const struct mmio_range *range;
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
        unsigned long base = dist->vgic_dist_base;
        bool updated_state;
        unsigned long offset;

        if (!irqchip_in_kernel(vcpu->kvm) ||
            mmio->phys_addr < base ||
            (mmio->phys_addr + mmio->len) > (base + KVM_VGIC_V2_DIST_SIZE))
                return false;

        /* We don't support ldrd / strd or ldm / stm to the emulated vgic */
        if (mmio->len > 4) {
                kvm_inject_dabt(vcpu, mmio->phys_addr);
                return true;
        }

        offset = mmio->phys_addr - base;
        range = find_matching_range(vgic_dist_ranges, mmio, offset);
        if (unlikely(!range || !range->handle_mmio)) {
                pr_warn("Unhandled access %d %08llx %d\n",
                        mmio->is_write, mmio->phys_addr, mmio->len);
                return false;
        }

        spin_lock(&vcpu->kvm->arch.vgic.lock);
        offset = mmio->phys_addr - range->base - base;
        updated_state = range->handle_mmio(vcpu, mmio, offset);
        spin_unlock(&vcpu->kvm->arch.vgic.lock);
        kvm_prepare_mmio(run, mmio);
        kvm_handle_mmio_return(vcpu, run);

        if (updated_state)
                vgic_kick_vcpus(vcpu->kvm);

        return true;
}

static void vgic_dispatch_sgi(struct kvm_vcpu *vcpu, u32 reg)
{
        struct kvm *kvm = vcpu->kvm;
        struct vgic_dist *dist = &kvm->arch.vgic;
        int nrcpus = atomic_read(&kvm->online_vcpus);
        u8 target_cpus;
        int sgi, mode, c, vcpu_id;

        vcpu_id = vcpu->vcpu_id;

        sgi = reg & 0xf;
        target_cpus = (reg >> 16) & 0xff;
        mode = (reg >> 24) & 3;

        switch (mode) {
        case 0:
                if (!target_cpus)
                        return;
                break;

        case 1:
                target_cpus = ((1 << nrcpus) - 1) & ~(1 << vcpu_id) & 0xff;
                break;

        case 2:
                target_cpus = 1 << vcpu_id;
                break;
        }

        kvm_for_each_vcpu(c, vcpu, kvm) {
                if (target_cpus & 1) {
                        /* Flag the SGI as pending */
                        vgic_dist_irq_set(vcpu, sgi);
                        dist->irq_sgi_sources[c][sgi] |= 1 << vcpu_id;
                        kvm_debug("SGI%d from CPU%d to CPU%d\n", sgi, vcpu_id, c);
                }

                target_cpus >>= 1;
        }
}

static int compute_pending_for_cpu(struct kvm_vcpu *vcpu)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
        unsigned long *pending, *enabled, *pend_percpu, *pend_shared;
        unsigned long pending_private, pending_shared;
        int vcpu_id;

        vcpu_id = vcpu->vcpu_id;
        pend_percpu = vcpu->arch.vgic_cpu.pending_percpu;
        pend_shared = vcpu->arch.vgic_cpu.pending_shared;

        pending = vgic_bitmap_get_cpu_map(&dist->irq_state, vcpu_id);
        enabled = vgic_bitmap_get_cpu_map(&dist->irq_enabled, vcpu_id);
        bitmap_and(pend_percpu, pending, enabled, VGIC_NR_PRIVATE_IRQS);

        pending = vgic_bitmap_get_shared_map(&dist->irq_state);
        enabled = vgic_bitmap_get_shared_map(&dist->irq_enabled);
        bitmap_and(pend_shared, pending, enabled, VGIC_NR_SHARED_IRQS);
        bitmap_and(pend_shared, pend_shared,
                   vgic_bitmap_get_shared_map(&dist->irq_spi_target[vcpu_id]),
                   VGIC_NR_SHARED_IRQS);

        pending_private = find_first_bit(pend_percpu, VGIC_NR_PRIVATE_IRQS);
        pending_shared = find_first_bit(pend_shared, VGIC_NR_SHARED_IRQS);
        return (pending_private < VGIC_NR_PRIVATE_IRQS ||
                pending_shared < VGIC_NR_SHARED_IRQS);
}

/*
 * Update the interrupt state and determine which CPUs have pending
 * interrupts. Must be called with distributor lock held.
 */
static void vgic_update_state(struct kvm *kvm)
{
        struct vgic_dist *dist = &kvm->arch.vgic;
        struct kvm_vcpu *vcpu;
        int c;

        if (!dist->enabled) {
                set_bit(0, &dist->irq_pending_on_cpu);
                return;
        }

        kvm_for_each_vcpu(c, vcpu, kvm) {
                if (compute_pending_for_cpu(vcpu)) {
                        pr_debug("CPU%d has pending interrupts\n", c);
                        set_bit(c, &dist->irq_pending_on_cpu);
                }
        }
}

static struct vgic_lr vgic_get_lr(const struct kvm_vcpu *vcpu, int lr)
{
        return vgic_ops->get_lr(vcpu, lr);
}

static void vgic_set_lr(struct kvm_vcpu *vcpu, int lr,
                               struct vgic_lr vlr)
{
        vgic_ops->set_lr(vcpu, lr, vlr);
}

static void vgic_sync_lr_elrsr(struct kvm_vcpu *vcpu, int lr,
                               struct vgic_lr vlr)
{
        vgic_ops->sync_lr_elrsr(vcpu, lr, vlr);
}

static inline u64 vgic_get_elrsr(struct kvm_vcpu *vcpu)
{
        return vgic_ops->get_elrsr(vcpu);
}

static inline u64 vgic_get_eisr(struct kvm_vcpu *vcpu)
{
        return vgic_ops->get_eisr(vcpu);
}

static inline u32 vgic_get_interrupt_status(struct kvm_vcpu *vcpu)
{
        return vgic_ops->get_interrupt_status(vcpu);
}

static inline void vgic_enable_underflow(struct kvm_vcpu *vcpu)
{
        vgic_ops->enable_underflow(vcpu);
}

static inline void vgic_disable_underflow(struct kvm_vcpu *vcpu)
{
        vgic_ops->disable_underflow(vcpu);
}

static inline void vgic_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr)
{
        vgic_ops->get_vmcr(vcpu, vmcr);
}

static void vgic_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr)
{
        vgic_ops->set_vmcr(vcpu, vmcr);
}

static inline void vgic_enable(struct kvm_vcpu *vcpu)
{
        vgic_ops->enable(vcpu);
}

static void vgic_retire_lr(int lr_nr, int irq, struct kvm_vcpu *vcpu)
{
        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
        struct vgic_lr vlr = vgic_get_lr(vcpu, lr_nr);

        vlr.state = 0;
        vgic_set_lr(vcpu, lr_nr, vlr);
        clear_bit(lr_nr, vgic_cpu->lr_used);
        vgic_cpu->vgic_irq_lr_map[irq] = LR_EMPTY;
}

/*
 * An interrupt may have been disabled after being made pending on the
 * CPU interface (the classic case is a timer running while we're
 * rebooting the guest - the interrupt would kick as soon as the CPU
 * interface gets enabled, with deadly consequences).
 *
 * The solution is to examine already active LRs, and check the
 * interrupt is still enabled. If not, just retire it.
 */
static void vgic_retire_disabled_irqs(struct kvm_vcpu *vcpu)
{
        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
        int lr;

        for_each_set_bit(lr, vgic_cpu->lr_used, vgic->nr_lr) {
                struct vgic_lr vlr = vgic_get_lr(vcpu, lr);

                if (!vgic_irq_is_enabled(vcpu, vlr.irq)) {
                        vgic_retire_lr(lr, vlr.irq, vcpu);
                        if (vgic_irq_is_active(vcpu, vlr.irq))
                                vgic_irq_clear_active(vcpu, vlr.irq);
                }
        }
}

/*
 * Queue an interrupt to a CPU virtual interface. Return true on success,
 * or false if it wasn't possible to queue it.
 */
static bool vgic_queue_irq(struct kvm_vcpu *vcpu, u8 sgi_source_id, int irq)
{
        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
        struct vgic_lr vlr;
        int lr;

        /* Sanitize the input... */
        BUG_ON(sgi_source_id & ~7);
        BUG_ON(sgi_source_id && irq >= VGIC_NR_SGIS);
        BUG_ON(irq >= VGIC_NR_IRQS);

        kvm_debug("Queue IRQ%d\n", irq);

        lr = vgic_cpu->vgic_irq_lr_map[irq];

        /* Do we have an active interrupt for the same CPUID? */
        if (lr != LR_EMPTY) {
                vlr = vgic_get_lr(vcpu, lr);
                if (vlr.source == sgi_source_id) {
                        kvm_debug("LR%d piggyback for IRQ%d\n", lr, vlr.irq);
                        BUG_ON(!test_bit(lr, vgic_cpu->lr_used));
                        vlr.state |= LR_STATE_PENDING;
                        vgic_set_lr(vcpu, lr, vlr);
                        return true;
                }
        }

        /* Try to use another LR for this interrupt */
        lr = find_first_zero_bit((unsigned long *)vgic_cpu->lr_used,
                               vgic->nr_lr);
        if (lr >= vgic->nr_lr)
                return false;

        kvm_debug("LR%d allocated for IRQ%d %x\n", lr, irq, sgi_source_id);
        vgic_cpu->vgic_irq_lr_map[irq] = lr;
        set_bit(lr, vgic_cpu->lr_used);

        vlr.irq = irq;
        vlr.source = sgi_source_id;
        vlr.state = LR_STATE_PENDING;
        if (!vgic_irq_is_edge(vcpu, irq))
                vlr.state |= LR_EOI_INT;

        vgic_set_lr(vcpu, lr, vlr);

        return true;
}

static bool vgic_queue_sgi(struct kvm_vcpu *vcpu, int irq)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
        unsigned long sources;
        int vcpu_id = vcpu->vcpu_id;
        int c;

        sources = dist->irq_sgi_sources[vcpu_id][irq];

        for_each_set_bit(c, &sources, VGIC_MAX_CPUS) {
                if (vgic_queue_irq(vcpu, c, irq))
                        clear_bit(c, &sources);
        }

        dist->irq_sgi_sources[vcpu_id][irq] = sources;

        /*
         * If the sources bitmap has been cleared it means that we
         * could queue all the SGIs onto link registers (see the
         * clear_bit above), and therefore we are done with them in
         * our emulated gic and can get rid of them.
         */
        if (!sources) {
                vgic_dist_irq_clear(vcpu, irq);
                vgic_cpu_irq_clear(vcpu, irq);
                return true;
        }

        return false;
}

static bool vgic_queue_hwirq(struct kvm_vcpu *vcpu, int irq)
{
        if (vgic_irq_is_active(vcpu, irq))
                return true; /* level interrupt, already queued */

        if (vgic_queue_irq(vcpu, 0, irq)) {
                if (vgic_irq_is_edge(vcpu, irq)) {
                        vgic_dist_irq_clear(vcpu, irq);
                        vgic_cpu_irq_clear(vcpu, irq);
                } else {
                        vgic_irq_set_active(vcpu, irq);
                }

                return true;
        }

        return false;
}

/*
 * Fill the list registers with pending interrupts before running the
 * guest.
 */
static void __kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
{
        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
        int i, vcpu_id;
        int overflow = 0;

        vcpu_id = vcpu->vcpu_id;

        /*
         * We may not have any pending interrupt, or the interrupts
         * may have been serviced from another vcpu. In all cases,
         * move along.
         */
        if (!kvm_vgic_vcpu_pending_irq(vcpu)) {
                pr_debug("CPU%d has no pending interrupt\n", vcpu_id);
                goto epilog;
        }

        /* SGIs */
        for_each_set_bit(i, vgic_cpu->pending_percpu, VGIC_NR_SGIS) {
                if (!vgic_queue_sgi(vcpu, i))
                        overflow = 1;
        }

        /* PPIs */
        for_each_set_bit_from(i, vgic_cpu->pending_percpu, VGIC_NR_PRIVATE_IRQS) {
                if (!vgic_queue_hwirq(vcpu, i))
                        overflow = 1;
        }

        /* SPIs */
        for_each_set_bit(i, vgic_cpu->pending_shared, VGIC_NR_SHARED_IRQS) {
                if (!vgic_queue_hwirq(vcpu, i + VGIC_NR_PRIVATE_IRQS))
                        overflow = 1;
        }

epilog:
        if (overflow) {
                vgic_enable_underflow(vcpu);
        } else {
                vgic_disable_underflow(vcpu);
                /*
                 * We're about to run this VCPU, and we've consumed
                 * everything the distributor had in store for
                 * us. Claim we don't have anything pending. We'll
                 * adjust that if needed while exiting.
                 */
                clear_bit(vcpu_id, &dist->irq_pending_on_cpu);
        }
}

static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
{
        u32 status = vgic_get_interrupt_status(vcpu);
        bool level_pending = false;

        kvm_debug("STATUS = %08x\n", status);

        if (status & INT_STATUS_EOI) {
                /*
                 * Some level interrupts have been EOIed. Clear their
                 * active bit.
                 */
                u64 eisr = vgic_get_eisr(vcpu);
                unsigned long *eisr_ptr = (unsigned long *)&eisr;
                int lr;

                for_each_set_bit(lr, eisr_ptr, vgic->nr_lr) {
                        struct vgic_lr vlr = vgic_get_lr(vcpu, lr);

                        vgic_irq_clear_active(vcpu, vlr.irq);
                        WARN_ON(vlr.state & LR_STATE_MASK);
                        vlr.state = 0;
                        vgic_set_lr(vcpu, lr, vlr);

                        /* Any additional pending interrupt? */
                        if (vgic_dist_irq_is_pending(vcpu, vlr.irq)) {
                                vgic_cpu_irq_set(vcpu, vlr.irq);
                                level_pending = true;
                        } else {
                                vgic_cpu_irq_clear(vcpu, vlr.irq);
                        }

                        /*
                         * Despite being EOIed, the LR may not have
                         * been marked as empty.
                         */
                        vgic_sync_lr_elrsr(vcpu, lr, vlr);
                }
        }

        if (status & INT_STATUS_UNDERFLOW)
                vgic_disable_underflow(vcpu);

        return level_pending;
}

/*
 * Sync back the VGIC state after a guest run. The distributor lock is
 * needed so we don't get preempted in the middle of the state processing.
 */
static void __kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
{
        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
        u64 elrsr;
        unsigned long *elrsr_ptr;
        int lr, pending;
        bool level_pending;

        level_pending = vgic_process_maintenance(vcpu);
        elrsr = vgic_get_elrsr(vcpu);
        elrsr_ptr = (unsigned long *)&elrsr;

        /* Clear mappings for empty LRs */
        for_each_set_bit(lr, elrsr_ptr, vgic->nr_lr) {
                struct vgic_lr vlr;

                if (!test_and_clear_bit(lr, vgic_cpu->lr_used))
                        continue;

                vlr = vgic_get_lr(vcpu, lr);

                BUG_ON(vlr.irq >= VGIC_NR_IRQS);
                vgic_cpu->vgic_irq_lr_map[vlr.irq] = LR_EMPTY;
        }

        /* Check if we still have something up our sleeve... */
        pending = find_first_zero_bit(elrsr_ptr, vgic->nr_lr);
        if (level_pending || pending < vgic->nr_lr)
                set_bit(vcpu->vcpu_id, &dist->irq_pending_on_cpu);
}

void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

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

        spin_lock(&dist->lock);
        __kvm_vgic_flush_hwstate(vcpu);
        spin_unlock(&dist->lock);
}

void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

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

        spin_lock(&dist->lock);
        __kvm_vgic_sync_hwstate(vcpu);
        spin_unlock(&dist->lock);
}

int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
{
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

        if (!irqchip_in_kernel(vcpu->kvm))
                return 0;

        return test_bit(vcpu->vcpu_id, &dist->irq_pending_on_cpu);
}

static void vgic_kick_vcpus(struct kvm *kvm)
{
        struct kvm_vcpu *vcpu;
        int c;

        /*
         * We've injected an interrupt, time to find out who deserves
         * a good kick...
         */
        kvm_for_each_vcpu(c, vcpu, kvm) {
                if (kvm_vgic_vcpu_pending_irq(vcpu))
                        kvm_vcpu_kick(vcpu);
        }
}

static int vgic_validate_injection(struct kvm_vcpu *vcpu, int irq, int level)
{
        int is_edge = vgic_irq_is_edge(vcpu, irq);
        int state = vgic_dist_irq_is_pending(vcpu, irq);

        /*
         * Only inject an interrupt if:
         * - edge triggered and we have a rising edge
         * - level triggered and we change level
         */
        if (is_edge)
                return level > state;
        else
                return level != state;
}

static bool vgic_update_irq_state(struct kvm *kvm, int cpuid,
                                  unsigned int irq_num, bool level)
{
        struct vgic_dist *dist = &kvm->arch.vgic;
        struct kvm_vcpu *vcpu;
        int is_edge, is_level;
        int enabled;
        bool ret = true;

        spin_lock(&dist->lock);

        vcpu = kvm_get_vcpu(kvm, cpuid);
        is_edge = vgic_irq_is_edge(vcpu, irq_num);
        is_level = !is_edge;

        if (!vgic_validate_injection(vcpu, irq_num, level)) {
                ret = false;
                goto out;
        }

        if (irq_num >= VGIC_NR_PRIVATE_IRQS) {
                cpuid = dist->irq_spi_cpu[irq_num - VGIC_NR_PRIVATE_IRQS];
                vcpu = kvm_get_vcpu(kvm, cpuid);
        }

        kvm_debug("Inject IRQ%d level %d CPU%d\n", irq_num, level, cpuid);

        if (level)
                vgic_dist_irq_set(vcpu, irq_num);
        else
                vgic_dist_irq_clear(vcpu, irq_num);

        enabled = vgic_irq_is_enabled(vcpu, irq_num);

        if (!enabled) {
                ret = false;
                goto out;
        }

        if (is_level && vgic_irq_is_active(vcpu, irq_num)) {
                /*
                 * Level interrupt in progress, will be picked up
                 * when EOId.
                 */
                ret = false;
                goto out;
        }

        if (level) {
                vgic_cpu_irq_set(vcpu, irq_num);
                set_bit(cpuid, &dist->irq_pending_on_cpu);
        }

out:
        spin_unlock(&dist->lock);

        return ret;
}

/**
 * kvm_vgic_inject_irq - Inject an IRQ from a device to the vgic
 * @kvm:     The VM structure pointer
 * @cpuid:   The CPU for PPIs
 * @irq_num: The IRQ number that is assigned to the device
 * @level:   Edge-triggered:  true:  to trigger the interrupt
 *                            false: to ignore the call
 *           Level-sensitive  true:  activates an interrupt
 *                            false: deactivates an interrupt
 *
 * The GIC is not concerned with devices being active-LOW or active-HIGH for
 * level-sensitive interrupts.  You can think of the level parameter as 1
 * being HIGH and 0 being LOW and all devices being active-HIGH.
 */
int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num,
                        bool level)
{
        if (vgic_update_irq_state(kvm, cpuid, irq_num, level))
                vgic_kick_vcpus(kvm);

        return 0;
}

static irqreturn_t vgic_maintenance_handler(int irq, void *data)
{
        /*
         * We cannot rely on the vgic maintenance interrupt to be
         * delivered synchronously. This means we can only use it to
         * exit the VM, and we perform the handling of EOIed
         * interrupts on the exit path (see vgic_process_maintenance).
         */
        return IRQ_HANDLED;
}

/**
 * kvm_vgic_vcpu_init - Initialize per-vcpu VGIC state
 * @vcpu: pointer to the vcpu struct
 *
 * Initialize the vgic_cpu struct and vgic_dist struct fields pertaining to
 * this vcpu and enable the VGIC for this VCPU
 */
int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
{
        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
        int i;

        if (vcpu->vcpu_id >= VGIC_MAX_CPUS)
                return -EBUSY;

        for (i = 0; i < VGIC_NR_IRQS; i++) {
                if (i < VGIC_NR_PPIS)
                        vgic_bitmap_set_irq_val(&dist->irq_enabled,
                                                vcpu->vcpu_id, i, 1);
                if (i < VGIC_NR_PRIVATE_IRQS)
                        vgic_bitmap_set_irq_val(&dist->irq_cfg,
                                                vcpu->vcpu_id, i, VGIC_CFG_EDGE);

                vgic_cpu->vgic_irq_lr_map[i] = LR_EMPTY;
        }

        /*
         * Store the number of LRs per vcpu, so we don't have to go
         * all the way to the distributor structure to find out. Only
         * assembly code should use this one.
         */
        vgic_cpu->nr_lr = vgic->nr_lr;

        vgic_enable(vcpu);

        return 0;
}

static void vgic_init_maintenance_interrupt(void *info)
{
        enable_percpu_irq(vgic->maint_irq, 0);
}

static int vgic_cpu_notify(struct notifier_block *self,
                           unsigned long action, void *cpu)
{
        switch (action) {
        case CPU_STARTING:
        case CPU_STARTING_FROZEN:
                vgic_init_maintenance_interrupt(NULL);
                break;
        case CPU_DYING:
        case CPU_DYING_FROZEN:
                disable_percpu_irq(vgic->maint_irq);
                break;
        }

        return NOTIFY_OK;
}

static struct notifier_block vgic_cpu_nb = {
        .notifier_call = vgic_cpu_notify,
};

static const struct of_device_id vgic_ids[] = {
        { .compatible = "arm,cortex-a15-gic", .data = vgic_v2_probe, },
        { .compatible = "arm,gic-v3", .data = vgic_v3_probe, },
        {},
};

int kvm_vgic_hyp_init(void)
{
        const struct of_device_id *matched_id;
        const int (*vgic_probe)(struct device_node *,const struct vgic_ops **,
                                const struct vgic_params **);
        struct device_node *vgic_node;
        int ret;

        vgic_node = of_find_matching_node_and_match(NULL,
                                                    vgic_ids, &matched_id);
        if (!vgic_node) {
                kvm_err("error: no compatible GIC node found\n");
                return -ENODEV;
        }

        vgic_probe = matched_id->data;
        ret = vgic_probe(vgic_node, &vgic_ops, &vgic);
        if (ret)
                return ret;

        ret = request_percpu_irq(vgic->maint_irq, vgic_maintenance_handler,
                                 "vgic", kvm_get_running_vcpus());
        if (ret) {
                kvm_err("Cannot register interrupt %d\n", vgic->maint_irq);
                return ret;
        }

        ret = __register_cpu_notifier(&vgic_cpu_nb);
        if (ret) {
                kvm_err("Cannot register vgic CPU notifier\n");
                goto out_free_irq;
        }

        /* Callback into for arch code for setup */
        vgic_arch_setup(vgic);

        on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);

        return 0;

out_free_irq:
        free_percpu_irq(vgic->maint_irq, kvm_get_running_vcpus());
        return ret;
}

/**
 * kvm_vgic_init - Initialize global VGIC state before running any VCPUs
 * @kvm: pointer to the kvm struct
 *
 * Map the virtual CPU interface into the VM before running any VCPUs.  We
 * can't do this at creation time, because user space must first set the
 * virtual CPU interface address in the guest physical address space.  Also
 * initialize the ITARGETSRn regs to 0 on the emulated distributor.
 */
int kvm_vgic_init(struct kvm *kvm)
{
        int ret = 0, i;

        if (!irqchip_in_kernel(kvm))
                return 0;

        mutex_lock(&kvm->lock);

        if (vgic_initialized(kvm))
                goto out;

        if (IS_VGIC_ADDR_UNDEF(kvm->arch.vgic.vgic_dist_base) ||
            IS_VGIC_ADDR_UNDEF(kvm->arch.vgic.vgic_cpu_base)) {
                kvm_err("Need to set vgic cpu and dist addresses first\n");
                ret = -ENXIO;
                goto out;
        }

        ret = kvm_phys_addr_ioremap(kvm, kvm->arch.vgic.vgic_cpu_base,
                                    vgic->vcpu_base, KVM_VGIC_V2_CPU_SIZE);
        if (ret) {
                kvm_err("Unable to remap VGIC CPU to VCPU\n");
                goto out;
        }

        for (i = VGIC_NR_PRIVATE_IRQS; i < VGIC_NR_IRQS; i += 4)
                vgic_set_target_reg(kvm, 0, i);

        kvm->arch.vgic.ready = true;
out:
        mutex_unlock(&kvm->lock);
        return ret;
}

int kvm_vgic_create(struct kvm *kvm)
{
        int i, vcpu_lock_idx = -1, ret = 0;
        struct kvm_vcpu *vcpu;

        mutex_lock(&kvm->lock);

        if (kvm->arch.vgic.vctrl_base) {
                ret = -EEXIST;
                goto out;
        }

        /*
         * Any time a vcpu is run, vcpu_load is called which tries to grab the
         * vcpu->mutex.  By grabbing the vcpu->mutex of all VCPUs we ensure
         * that no other VCPUs are run while we create the vgic.
         */
        kvm_for_each_vcpu(i, vcpu, kvm) {
                if (!mutex_trylock(&vcpu->mutex))
                        goto out_unlock;
                vcpu_lock_idx = i;
        }

        kvm_for_each_vcpu(i, vcpu, kvm) {
                if (vcpu->arch.has_run_once) {
                        ret = -EBUSY;
                        goto out_unlock;
                }
        }

        spin_lock_init(&kvm->arch.vgic.lock);
        kvm->arch.vgic.in_kernel = true;
        kvm->arch.vgic.vctrl_base = vgic->vctrl_base;
        kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
        kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;

out_unlock:
        for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
                vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
                mutex_unlock(&vcpu->mutex);
        }

out:
        mutex_unlock(&kvm->lock);
        return ret;
}

static int vgic_ioaddr_overlap(struct kvm *kvm)
{
        phys_addr_t dist = kvm->arch.vgic.vgic_dist_base;
        phys_addr_t cpu = kvm->arch.vgic.vgic_cpu_base;

        if (IS_VGIC_ADDR_UNDEF(dist) || IS_VGIC_ADDR_UNDEF(cpu))
                return 0;
        if ((dist <= cpu && dist + KVM_VGIC_V2_DIST_SIZE > cpu) ||
            (cpu <= dist && cpu + KVM_VGIC_V2_CPU_SIZE > dist))
                return -EBUSY;
        return 0;
}

static int vgic_ioaddr_assign(struct kvm *kvm, phys_addr_t *ioaddr,
                              phys_addr_t addr, phys_addr_t size)
{
        int ret;

        if (addr & ~KVM_PHYS_MASK)
                return -E2BIG;

        if (addr & (SZ_4K - 1))
                return -EINVAL;

        if (!IS_VGIC_ADDR_UNDEF(*ioaddr))
                return -EEXIST;
        if (addr + size < addr)
                return -EINVAL;

        *ioaddr = addr;
        ret = vgic_ioaddr_overlap(kvm);
        if (ret)
                *ioaddr = VGIC_ADDR_UNDEF;

        return ret;
}

/**
 * kvm_vgic_addr - set or get vgic VM base addresses
 * @kvm:   pointer to the vm struct
 * @type:  the VGIC addr type, one of KVM_VGIC_V2_ADDR_TYPE_XXX
 * @addr:  pointer to address value
 * @write: if true set the address in the VM address space, if false read the
 *          address
 *
 * Set or get the vgic base addresses for the distributor and the virtual CPU
 * interface in the VM physical address space.  These addresses are properties
 * of the emulated core/SoC and therefore user space initially knows this
 * information.
 */
int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
{
        int r = 0;
        struct vgic_dist *vgic = &kvm->arch.vgic;

        mutex_lock(&kvm->lock);
        switch (type) {
        case KVM_VGIC_V2_ADDR_TYPE_DIST:
                if (write) {
                        r = vgic_ioaddr_assign(kvm, &vgic->vgic_dist_base,
                                               *addr, KVM_VGIC_V2_DIST_SIZE);
                } else {
                        *addr = vgic->vgic_dist_base;
                }
                break;
        case KVM_VGIC_V2_ADDR_TYPE_CPU:
                if (write) {
                        r = vgic_ioaddr_assign(kvm, &vgic->vgic_cpu_base,
                                               *addr, KVM_VGIC_V2_CPU_SIZE);
                } else {
                        *addr = vgic->vgic_cpu_base;
                }
                break;
        default:
                r = -ENODEV;
        }

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

static bool handle_cpu_mmio_misc(struct kvm_vcpu *vcpu,
                                 struct kvm_exit_mmio *mmio, phys_addr_t offset)
{
        bool updated = false;
        struct vgic_vmcr vmcr;
        u32 *vmcr_field;
        u32 reg;

        vgic_get_vmcr(vcpu, &vmcr);

        switch (offset & ~0x3) {
        case GIC_CPU_CTRL:
                vmcr_field = &vmcr.ctlr;
                break;
        case GIC_CPU_PRIMASK:
                vmcr_field = &vmcr.pmr;
                break;
        case GIC_CPU_BINPOINT:
                vmcr_field = &vmcr.bpr;
                break;
        case GIC_CPU_ALIAS_BINPOINT:
                vmcr_field = &vmcr.abpr;
                break;
        default:
                BUG();
        }

        if (!mmio->is_write) {
                reg = *vmcr_field;
                mmio_data_write(mmio, ~0, reg);
        } else {
                reg = mmio_data_read(mmio, ~0);
                if (reg != *vmcr_field) {
                        *vmcr_field = reg;
                        vgic_set_vmcr(vcpu, &vmcr);
                        updated = true;
                }
        }
        return updated;
}

static bool handle_mmio_abpr(struct kvm_vcpu *vcpu,
                             struct kvm_exit_mmio *mmio, phys_addr_t offset)
{
        return handle_cpu_mmio_misc(vcpu, mmio, GIC_CPU_ALIAS_BINPOINT);
}

static bool handle_cpu_mmio_ident(struct kvm_vcpu *vcpu,
                                  struct kvm_exit_mmio *mmio,
                                  phys_addr_t offset)
{
        u32 reg;

        if (mmio->is_write)
                return false;

        /* GICC_IIDR */
        reg = (PRODUCT_ID_KVM << 20) |
              (GICC_ARCH_VERSION_V2 << 16) |
              (IMPLEMENTER_ARM << 0);
        mmio_data_write(mmio, ~0, reg);
        return false;
}

/*
 * CPU Interface Register accesses - these are not accessed by the VM, but by
 * user space for saving and restoring VGIC state.
 */
static const struct mmio_range vgic_cpu_ranges[] = {
        {
                .base           = GIC_CPU_CTRL,
                .len            = 12,
                .handle_mmio    = handle_cpu_mmio_misc,
        },
        {
                .base           = GIC_CPU_ALIAS_BINPOINT,
                .len            = 4,
                .handle_mmio    = handle_mmio_abpr,
        },
        {
                .base           = GIC_CPU_ACTIVEPRIO,
                .len            = 16,
                .handle_mmio    = handle_mmio_raz_wi,
        },
        {
                .base           = GIC_CPU_IDENT,
                .len            = 4,
                .handle_mmio    = handle_cpu_mmio_ident,
        },
};

static int vgic_attr_regs_access(struct kvm_device *dev,
                                 struct kvm_device_attr *attr,
                                 u32 *reg, bool is_write)
{
        const struct mmio_range *r = NULL, *ranges;
        phys_addr_t offset;
        int ret, cpuid, c;
        struct kvm_vcpu *vcpu, *tmp_vcpu;
        struct vgic_dist *vgic;
        struct kvm_exit_mmio mmio;

        offset = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK;
        cpuid = (attr->attr & KVM_DEV_ARM_VGIC_CPUID_MASK) >>
                KVM_DEV_ARM_VGIC_CPUID_SHIFT;

        mutex_lock(&dev->kvm->lock);

        if (cpuid >= atomic_read(&dev->kvm->online_vcpus)) {
                ret = -EINVAL;
                goto out;
        }

        vcpu = kvm_get_vcpu(dev->kvm, cpuid);
        vgic = &dev->kvm->arch.vgic;

        mmio.len = 4;
        mmio.is_write = is_write;
        if (is_write)
                mmio_data_write(&mmio, ~0, *reg);
        switch (attr->group) {
        case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
                mmio.phys_addr = vgic->vgic_dist_base + offset;
                ranges = vgic_dist_ranges;
                break;
        case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
                mmio.phys_addr = vgic->vgic_cpu_base + offset;
                ranges = vgic_cpu_ranges;
                break;
        default:
                BUG();
        }
        r = find_matching_range(ranges, &mmio, offset);

        if (unlikely(!r || !r->handle_mmio)) {
                ret = -ENXIO;
                goto out;
        }


        spin_lock(&vgic->lock);

        /*
         * Ensure that no other VCPU is running by checking the vcpu->cpu
         * field.  If no other VPCUs are running we can safely access the VGIC
         * state, because even if another VPU is run after this point, that
         * VCPU will not touch the vgic state, because it will block on
         * getting the vgic->lock in kvm_vgic_sync_hwstate().
         */
        kvm_for_each_vcpu(c, tmp_vcpu, dev->kvm) {
                if (unlikely(tmp_vcpu->cpu != -1)) {
                        ret = -EBUSY;
                        goto out_vgic_unlock;
                }
        }

        /*
         * Move all pending IRQs from the LRs on all VCPUs so the pending
         * state can be properly represented in the register state accessible
         * through this API.
         */
        kvm_for_each_vcpu(c, tmp_vcpu, dev->kvm)
                vgic_unqueue_irqs(tmp_vcpu);

        offset -= r->base;
        r->handle_mmio(vcpu, &mmio, offset);

        if (!is_write)
                *reg = mmio_data_read(&mmio, ~0);

        ret = 0;
out_vgic_unlock:
        spin_unlock(&vgic->lock);
out:
        mutex_unlock(&dev->kvm->lock);
        return ret;
}

static int vgic_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
{
        int r;

        switch (attr->group) {
        case KVM_DEV_ARM_VGIC_GRP_ADDR: {
                u64 __user *uaddr = (u64 __user *)(long)attr->addr;
                u64 addr;
                unsigned long type = (unsigned long)attr->attr;

                if (copy_from_user(&addr, uaddr, sizeof(addr)))
                        return -EFAULT;

                r = kvm_vgic_addr(dev->kvm, type, &addr, true);
                return (r == -ENODEV) ? -ENXIO : r;
        }

        case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
        case KVM_DEV_ARM_VGIC_GRP_CPU_REGS: {
                u32 __user *uaddr = (u32 __user *)(long)attr->addr;
                u32 reg;

                if (get_user(reg, uaddr))
                        return -EFAULT;

                return vgic_attr_regs_access(dev, attr, &reg, true);
        }

        }

        return -ENXIO;
}

static int vgic_get_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
{
        int r = -ENXIO;

        switch (attr->group) {
        case KVM_DEV_ARM_VGIC_GRP_ADDR: {
                u64 __user *uaddr = (u64 __user *)(long)attr->addr;
                u64 addr;
                unsigned long type = (unsigned long)attr->attr;

                r = kvm_vgic_addr(dev->kvm, type, &addr, false);
                if (r)
                        return (r == -ENODEV) ? -ENXIO : r;

                if (copy_to_user(uaddr, &addr, sizeof(addr)))
                        return -EFAULT;
                break;
        }

        case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
        case KVM_DEV_ARM_VGIC_GRP_CPU_REGS: {
                u32 __user *uaddr = (u32 __user *)(long)attr->addr;
                u32 reg = 0;

                r = vgic_attr_regs_access(dev, attr, &reg, false);
                if (r)
                        return r;
                r = put_user(reg, uaddr);
                break;
        }

        }

        return r;
}

static int vgic_has_attr_regs(const struct mmio_range *ranges,
                              phys_addr_t offset)
{
        struct kvm_exit_mmio dev_attr_mmio;

        dev_attr_mmio.len = 4;
        if (find_matching_range(ranges, &dev_attr_mmio, offset))
                return 0;
        else
                return -ENXIO;
}

static int vgic_has_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
{
        phys_addr_t offset;

        switch (attr->group) {
        case KVM_DEV_ARM_VGIC_GRP_ADDR:
                switch (attr->attr) {
                case KVM_VGIC_V2_ADDR_TYPE_DIST:
                case KVM_VGIC_V2_ADDR_TYPE_CPU:
                        return 0;
                }
                break;
        case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
                offset = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK;
                return vgic_has_attr_regs(vgic_dist_ranges, offset);
        case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
                offset = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK;
                return vgic_has_attr_regs(vgic_cpu_ranges, offset);
        }
        return -ENXIO;
}

static void vgic_destroy(struct kvm_device *dev)
{
        kfree(dev);
}

static int vgic_create(struct kvm_device *dev, u32 type)
{
        return kvm_vgic_create(dev->kvm);
}

struct kvm_device_ops kvm_arm_vgic_v2_ops = {
        .name = "kvm-arm-vgic",
        .create = vgic_create,
        .destroy = vgic_destroy,
        .set_attr = vgic_set_attr,
        .get_attr = vgic_get_attr,
        .has_attr = vgic_has_attr,
};