[PATCH 1/2] KVM: x86/pmu: Set MSR_IA32_MISC_ENABLE_EMON when vPMU is enabled

[Like Xu]

On Intel platforms, software may uses IA32_MISC_ENABLE[7]
bit to detect whether the performance monitoring facility
is supported in the processor.

A write to this PMU available bit will be ignored.

Cc: Yao Yuan <yuan.yao@xxxxxxxxx>
Signed-off-by: Like Xu <like.xu@xxxxxxxxxxxxxxx>
---
 arch/x86/kvm/vmx/pmu_intel.c | 2 ++
 arch/x86/kvm/x86.c           | 1 +
 2 files changed, 3 insertions(+)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index a886a47daebd..01c7d84ecf3e 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -339,6 +339,8 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 	if (!pmu->version)
 		return;
 
+	vcpu->arch.ia32_misc_enable_msr |= MSR_IA32_MISC_ENABLE_EMON;
+
 	perf_get_x86_pmu_capability(&x86_pmu);
 	if (guest_cpuid_has(vcpu, X86_FEATURE_PDCM))
 		vcpu->arch.perf_capabilities = vmx_get_perf_capabilities();
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c4015a43cc8a..d7b8f98ada93 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3042,6 +3042,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		}
 		break;
 	case MSR_IA32_MISC_ENABLE:
+		data &= ~MSR_IA32_MISC_ENABLE_EMON;
 		if (!kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT) &&
 		    ((vcpu->arch.ia32_misc_enable_msr ^ data) & MSR_IA32_MISC_ENABLE_MWAIT)) {
 			if (!guest_cpuid_has(vcpu, X86_FEATURE_XMM3))
-- 
2.21.3