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.d...@arm.com>
Signed-off-by: Marc Zyngier <marc.zyng...@arm.com>
---
arch/arm/include/asm/kvm_host.h | 12 ++++++++++++
arch/arm64/include/asm/kvm_host.h | 23 +++++++++++++++++++++++
arch/arm64/kvm/reset.c | 4 ++++
virt/kvm/arm/psci.c | 18 ++++++++++++++++--
4 files changed, 55 insertions(+), 2 deletions(-)
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index c7c28c885a19..d478766b56c1 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -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_EL1_ENTRY 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) {}
diff --git a/arch/arm64/include/asm/kvm_host.h
b/arch/arm64/include/asm/kvm_host.h
index 9bef3f69bdcd..082b0dbb85c6 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -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_EL1_ENTRY 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_EL1_ENTRY:
+ return KVM_SSBD_EL1_ENTRY;
+ 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);
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 3256b9228e75..20a7dfee8494 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -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_EL1_ENTRY)
+ vcpu->arch.workaround_flags |= VCPU_WORKAROUND_2_FLAG;
+
/* Reset timer */
return kvm_timer_vcpu_reset(vcpu);
}
diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c
index c4762bef13c6..4843bfa1f986 100644
--- a/virt/kvm/arm/psci.c
+++ b/virt/kvm/arm/psci.c
@@ -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_EL1_ENTRY:
+ val = SMCCC_RET_SUCCESS;
+ break;
+ case KVM_SSBD_FORCE_ENABLE:
+ case KVM_SSBD_MITIGATED:
+ val = SMCCC_RET_NOT_REQUIRED;
+ break;
+ }
break;
}
break;
--
2.14.2
