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arm64: KVM: Add ARCH_WORKAROUND_2 discovery through ARCH_FEATURES_FUNC_ID 

Now that all our infrastructure is in place, let's expose the
availability of ARCH_WORKAROUND_2 to guests. We take this opportunity
to tidy up a couple of SMCCC constants.

Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Marc Zyngier 2018-05-29 13:11:18 +01:00 committed by Catalin Marinas
parent b4f18c063a
commit 5d81f7dc9b
4 changed files with 55 additions and 2 deletions
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12
arch/arm/include/asm/kvm_host.h
View File

@ -315,6 +315,18 @@ static inline bool kvm_arm_harden_branch_predictor(void)
return false;
}
#define KVM_SSBD_UNKNOWN -1
#define KVM_SSBD_FORCE_DISABLE 0
#define KVM_SSBD_KERNEL 1
#define KVM_SSBD_FORCE_ENABLE 2
#define KVM_SSBD_MITIGATED 3
static inline int kvm_arm_have_ssbd(void)
{
/* No way to detect it yet, pretend it is not there. */
return KVM_SSBD_UNKNOWN;
}
static inline void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu) {}
static inline void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu) {}

23
arch/arm64/include/asm/kvm_host.h
View File

@ -455,6 +455,29 @@ static inline bool kvm_arm_harden_branch_predictor(void)
return cpus_have_const_cap(ARM64_HARDEN_BRANCH_PREDICTOR);
}
#define KVM_SSBD_UNKNOWN -1
#define KVM_SSBD_FORCE_DISABLE 0
#define KVM_SSBD_KERNEL 1
#define KVM_SSBD_FORCE_ENABLE 2
#define KVM_SSBD_MITIGATED 3
static inline int kvm_arm_have_ssbd(void)
{
switch (arm64_get_ssbd_state()) {
case ARM64_SSBD_FORCE_DISABLE:
return KVM_SSBD_FORCE_DISABLE;
case ARM64_SSBD_KERNEL:
return KVM_SSBD_KERNEL;
case ARM64_SSBD_FORCE_ENABLE:
return KVM_SSBD_FORCE_ENABLE;
case ARM64_SSBD_MITIGATED:
return KVM_SSBD_MITIGATED;
case ARM64_SSBD_UNKNOWN:
default:
return KVM_SSBD_UNKNOWN;
}
}
void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu);
void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu);

4
arch/arm64/kvm/reset.c
View File

@ -122,6 +122,10 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
/* Reset PMU */
kvm_pmu_vcpu_reset(vcpu);
/* Default workaround setup is enabled (if supported) */
if (kvm_arm_have_ssbd() == KVM_SSBD_KERNEL)
vcpu->arch.workaround_flags |= VCPU_WORKAROUND_2_FLAG;
/* Reset timer */
return kvm_timer_vcpu_reset(vcpu);
}

18
virt/kvm/arm/psci.c
View File

@ -405,7 +405,7 @@ static int kvm_psci_call(struct kvm_vcpu *vcpu)
int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
{
u32 func_id = smccc_get_function(vcpu);
u32 val = PSCI_RET_NOT_SUPPORTED;
u32 val = SMCCC_RET_NOT_SUPPORTED;
u32 feature;
switch (func_id) {
@ -417,7 +417,21 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
switch(feature) {
case ARM_SMCCC_ARCH_WORKAROUND_1:
if (kvm_arm_harden_branch_predictor())
val = 0;
val = SMCCC_RET_SUCCESS;
break;
case ARM_SMCCC_ARCH_WORKAROUND_2:
switch (kvm_arm_have_ssbd()) {
case KVM_SSBD_FORCE_DISABLE:
case KVM_SSBD_UNKNOWN:
break;
case KVM_SSBD_KERNEL:
val = SMCCC_RET_SUCCESS;
break;
case KVM_SSBD_FORCE_ENABLE:
case KVM_SSBD_MITIGATED:
val = SMCCC_RET_NOT_REQUIRED;
break;
}
break;
}
break;