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KVM: arm64: Allow SMCCC_ARCH_WORKAROUND_3 to be discovered and migrated

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KVM allows the guest to discover whether the ARCH_WORKAROUND SMCCC are
implemented, and to preserve that state during migration through its
firmware register interface.

Add the necessary boiler plate for SMCCC_ARCH_WORKAROUND_3.

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
This commit is contained in:
James Morse 2021-12-10 11:16:18 +00:00
parent 558c303c97
commit a5905d6af4
3 changed files with 34 additions and 1 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

5
arch/arm64/include/uapi/asm/kvm.h
View file

@ -281,6 +281,11 @@ struct kvm_arm_copy_mte_tags {
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED 3 #define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED 3
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED (1U << 4) #define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED (1U << 4)
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 KVM_REG_ARM_FW_REG(3)
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL 0
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_AVAIL 1
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_REQUIRED 2
/* SVE registers */ /* SVE registers */
#define KVM_REG_ARM64_SVE (0x15 << KVM_REG_ARM_COPROC_SHIFT) #define KVM_REG_ARM64_SVE (0x15 << KVM_REG_ARM_COPROC_SHIFT)

12
arch/arm64/kvm/hypercalls.c
View file

@ -107,6 +107,18 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
break; break;
} }
break; break;
case ARM_SMCCC_ARCH_WORKAROUND_3:
switch (arm64_get_spectre_bhb_state()) {
case SPECTRE_VULNERABLE:
break;
case SPECTRE_MITIGATED:
val[0] = SMCCC_RET_SUCCESS;
break;
case SPECTRE_UNAFFECTED:
val[0] = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
break;
}
break;
case ARM_SMCCC_HV_PV_TIME_FEATURES: case ARM_SMCCC_HV_PV_TIME_FEATURES:
val[0] = SMCCC_RET_SUCCESS; val[0] = SMCCC_RET_SUCCESS;
break; break;

18
arch/arm64/kvm/psci.c
View file

@ -406,7 +406,7 @@ int kvm_psci_call(struct kvm_vcpu *vcpu)
int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu) int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
{ {
return 3; /* PSCI version and two workaround registers */ return 4; /* PSCI version and three workaround registers */
} }
int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices) int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
@ -420,6 +420,9 @@ int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2, uindices++)) if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2, uindices++))
return -EFAULT; return -EFAULT;
if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3, uindices++))
return -EFAULT;
return 0; return 0;
} }
@ -459,6 +462,17 @@ static int get_kernel_wa_level(u64 regid)
case SPECTRE_VULNERABLE: case SPECTRE_VULNERABLE:
return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL; return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
} }
break;
case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
switch (arm64_get_spectre_bhb_state()) {
case SPECTRE_VULNERABLE:
return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL;
case SPECTRE_MITIGATED:
return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_AVAIL;
case SPECTRE_UNAFFECTED:
return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_REQUIRED;
}
return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL;
} }
return -EINVAL; return -EINVAL;
@ -475,6 +489,7 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
break; break;
case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1: case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2: case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK; val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK;
break; break;
default: default:
@ -520,6 +535,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
} }
case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1: case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
if (val & ~KVM_REG_FEATURE_LEVEL_MASK) if (val & ~KVM_REG_FEATURE_LEVEL_MASK)
return -EINVAL; return -EINVAL;