arch/arm64/kvm/reset.c

   1 /*
   2  * Copyright (C) 2012,2013 - ARM Ltd
   3  * Author: Marc Zyngier <marc.zyngier@arm.com>
   4  *
   5  * Derived from arch/arm/kvm/reset.c
   6  * Copyright (C) 2012 - Virtual Open Systems and Columbia University
   7  * Author: Christoffer Dall <c.dall@virtualopensystems.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License, version 2, as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include <linux/errno.h>
  23 #include <linux/kvm_host.h>
  24 #include <linux/kvm.h>
  25 #include <linux/hw_breakpoint.h>
  26
  27 #include <kvm/arm_arch_timer.h>
  28
  29 #include <asm/cputype.h>
  30 #include <asm/ptrace.h>
  31 #include <asm/kvm_arm.h>
  32 #include <asm/kvm_asm.h>
  33 #include <asm/kvm_coproc.h>
  34 #include <asm/kvm_mmu.h>
  35
  36 /*
  37  * ARMv8 Reset Values
  38  */
  39 static const struct kvm_regs default_regs_reset = {
  40         .regs.pstate = (PSR_MODE_EL1h | PSR_A_BIT | PSR_I_BIT |
  41                         PSR_F_BIT | PSR_D_BIT),
  42 };
  43
  44 static const struct kvm_regs default_regs_reset32 = {
  45         .regs.pstate = (COMPAT_PSR_MODE_SVC | COMPAT_PSR_A_BIT |
  46                         COMPAT_PSR_I_BIT | COMPAT_PSR_F_BIT),
  47 };
  48
  49 static const struct kvm_irq_level default_vtimer_irq = {
  50         .irq    = 27,
  51         .level  = 1,
  52 };
  53
  54 static bool cpu_has_32bit_el1(void)
  55 {
  56         u64 pfr0;
  57
  58         pfr0 = read_system_reg(SYS_ID_AA64PFR0_EL1);
  59         return !!(pfr0 & 0x20);
  60 }
  61
  62 /**
  63  * kvm_arch_dev_ioctl_check_extension
  64  *
  65  * We currently assume that the number of HW registers is uniform
  66  * across all CPUs (see cpuinfo_sanity_check).
  67  */
  68 int kvm_arch_dev_ioctl_check_extension(long ext)
  69 {
  70         int r;
  71
  72         switch (ext) {
  73         case KVM_CAP_ARM_EL1_32BIT:
  74                 r = cpu_has_32bit_el1();
  75                 break;
  76         case KVM_CAP_GUEST_DEBUG_HW_BPS:
  77                 r = get_num_brps();
  78                 break;
  79         case KVM_CAP_GUEST_DEBUG_HW_WPS:
  80                 r = get_num_wrps();
  81                 break;
  82         case KVM_CAP_ARM_PMU_V3:
  83                 r = kvm_arm_support_pmu_v3();
  84                 break;
  85         case KVM_CAP_SET_GUEST_DEBUG:
  86         case KVM_CAP_VCPU_ATTRIBUTES:
  87                 r = 1;
  88                 break;
  89         default:
  90                 r = 0;
  91         }
  92
  93         return r;
  94 }
  95
  96 /**
  97  * kvm_reset_vcpu - sets core registers and sys_regs to reset value
  98  * @vcpu: The VCPU pointer
  99  *
 100  * This function finds the right table above and sets the registers on
 101  * the virtual CPU struct to their architectually defined reset
 102  * values.
 103  */
 104 int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 105 {
 106         const struct kvm_irq_level *cpu_vtimer_irq;
 107         const struct kvm_regs *cpu_reset;
 108
 109         switch (vcpu->arch.target) {
 110         default:
 111                 if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) {
 112                         if (!cpu_has_32bit_el1())
 113                                 return -EINVAL;
 114                         cpu_reset = &default_regs_reset32;
 115                 } else {
 116                         cpu_reset = &default_regs_reset;
 117                 }
 118
 119                 cpu_vtimer_irq = &default_vtimer_irq;
 120                 break;
 121         }
 122
 123         /* Reset core registers */
 124         memcpy(vcpu_gp_regs(vcpu), cpu_reset, sizeof(*cpu_reset));
 125
 126         /* Reset system registers */
 127         kvm_reset_sys_regs(vcpu);
 128
 129         /* Reset PMU */
 130         kvm_pmu_vcpu_reset(vcpu);
 131
 132         /* Reset timer */
 133         return kvm_timer_vcpu_reset(vcpu, cpu_vtimer_irq);
 134 }
 135
 136 extern char __hyp_idmap_text_start[];
 137
 138 unsigned long kvm_hyp_reset_entry(void)
 139 {
 140         if (!__kvm_cpu_uses_extended_idmap()) {
 141                 unsigned long offset;
 142
 143                 /*
 144                  * Find the address of __kvm_hyp_reset() in the trampoline page.
 145                  * This is present in the running page tables, and the boot page
 146                  * tables, so we call the code here to start the trampoline
 147                  * dance in reverse.
 148                  */
 149                 offset = (unsigned long)__kvm_hyp_reset
 150                          - ((unsigned long)__hyp_idmap_text_start & PAGE_MASK);
 151
 152                 return TRAMPOLINE_VA + offset;
 153         } else {
 154                 /*
 155                  * KVM is running with merged page tables, which don't have the
 156                  * trampoline page mapped. We know the idmap is still mapped,
 157                  * but can't be called into directly. Use
 158                  * __extended_idmap_trampoline to do the call.
 159                  */
 160                 return (unsigned long)kvm_ksym_ref(__extended_idmap_trampoline);
 161         }
 162 }