From: Zhang Chen <chen.zhang@xxxxxxxxx>
Allow guest to report if the short BHB-clearing sequence is in use.
KVM will deploy BHI_DIS_S for the guest if the short BHB-clearing
sequence is in use and the processor doesn't enumerate BHI_NO.
Signed-off-by: Zhang Chen <chen.zhang@xxxxxxxxx>
Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
---
arch/x86/kvm/vmx/vmx.c | 31 ++++++++++++++++++++++++++++---
1 file changed, 28 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index cc260b14f8df..c5ceaebd954b 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1956,8 +1956,8 @@ static inline bool is_vmx_feature_control_msr_valid(struct vcpu_vmx *vmx,
}
#define VIRTUAL_ENUMERATION_VALID_BITS VIRT_ENUM_MITIGATION_CTRL_SUPPORT
-#define MITI_ENUM_VALID_BITS 0ULL
-#define MITI_CTRL_VALID_BITS 0ULL
+#define MITI_ENUM_VALID_BITS MITI_ENUM_BHB_CLEAR_SEQ_S_SUPPORT
+#define MITI_CTRL_VALID_BITS MITI_CTRL_BHB_CLEAR_SEQ_S_USED
static int vmx_get_msr_feature(struct kvm_msr_entry *msr)
{
@@ -2204,7 +2204,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
struct vmx_uret_msr *msr;
int ret = 0;
u32 msr_index = msr_info->index;
- u64 data = msr_info->data;
+ u64 data = msr_info->data, spec_ctrl_mask = 0;
u32 index;
switch (msr_index) {
@@ -2508,6 +2508,31 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
if (data & ~MITI_CTRL_VALID_BITS)
return 1;
+ if (data & MITI_CTRL_BHB_CLEAR_SEQ_S_USED &&
+ kvm_cpu_cap_has(X86_FEATURE_BHI_CTRL) &&
+ !(host_arch_capabilities & ARCH_CAP_BHI_NO))
+ spec_ctrl_mask |= SPEC_CTRL_BHI_DIS_S;
+
+ /*
+ * Intercept IA32_SPEC_CTRL to disallow guest from changing
+ * certain bits if "virtualize IA32_SPEC_CTRL" isn't supported
+ * e.g., in nested case.
+ */
+ if (spec_ctrl_mask && !cpu_has_spec_ctrl_shadow())
+ vmx_enable_intercept_for_msr(vcpu, MSR_IA32_SPEC_CTRL, MSR_TYPE_RW);
+
+ /*
+ * KVM_CAP_FORCE_SPEC_CTRL takes precedence over
+ * MSR_VIRTUAL_MITIGATION_CTRL.
+ */
+ spec_ctrl_mask &= ~vmx->vcpu.kvm->arch.force_spec_ctrl_mask;
+
+ vmx->force_spec_ctrl_mask = vmx->vcpu.kvm->arch.force_spec_ctrl_mask |
+ spec_ctrl_mask;
+ vmx->force_spec_ctrl_value = vmx->vcpu.kvm->arch.force_spec_ctrl_value |
+ spec_ctrl_mask;
+ vmx_set_spec_ctrl(&vmx->vcpu, vmx->spec_ctrl_shadow);
+
vmx->msr_virtual_mitigation_ctrl = data;
break;
default:
--
2.39.3
