diff mbox series

[V8,13/18] KVM: x86: Set PEBS_UNAVAIL in IA32_MISC_ENABLE when PEBS is enabled

Message ID 20210716085325.10300-14-lingshan.zhu@intel.com (mailing list archive)
State New, archived
Headers show
Series KVM: x86/pmu: Add *basic* support to enable guest PEBS via DS | expand

Commit Message

Zhu, Lingshan July 16, 2021, 8:53 a.m. UTC 
From: Like Xu <like.xu@linux.intel.com>

The bit 12 represents "Processor Event Based Sampling Unavailable (RO)" :
	1 = PEBS is not supported.
	0 = PEBS is supported.

A write to this PEBS_UNAVL available bit will bring #GP(0) when guest PEBS
is enabled. Some PEBS drivers in guest may care about this bit.

Signed-off-by: Like Xu <like.xu@linux.intel.com>
Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
---
 arch/x86/kvm/vmx/pmu_intel.c | 2 ++
 arch/x86/kvm/x86.c           | 4 ++++
 2 files changed, 6 insertions(+)
diff mbox series

Patch

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 58f32a55cc2e..296246bf253d 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -588,6 +588,7 @@  static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 		bitmap_set(pmu->all_valid_pmc_idx, INTEL_PMC_IDX_FIXED_VLBR, 1);
 
 	if (vcpu->arch.perf_capabilities & PERF_CAP_PEBS_FORMAT) {
+		vcpu->arch.ia32_misc_enable_msr &= ~MSR_IA32_MISC_ENABLE_PEBS_UNAVAIL;
 		if (vcpu->arch.perf_capabilities & PERF_CAP_PEBS_BASELINE) {
 			pmu->pebs_enable_mask = ~pmu->global_ctrl;
 			pmu->reserved_bits &= ~ICL_EVENTSEL_ADAPTIVE;
@@ -601,6 +602,7 @@  static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 				~((1ull << pmu->nr_arch_gp_counters) - 1);
 		}
 	} else {
+		vcpu->arch.ia32_misc_enable_msr |= MSR_IA32_MISC_ENABLE_PEBS_UNAVAIL;
 		vcpu->arch.perf_capabilities &= ~PERF_CAP_PEBS_MASK;
 	}
 }
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2f5d1ed00e4a..d3987a217ebe 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3322,6 +3322,10 @@  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 (!msr_info->host_initiated &&
+		    (vcpu->arch.perf_capabilities & PERF_CAP_PEBS_FORMAT) &&
+		    (data & MSR_IA32_MISC_ENABLE_PEBS_UNAVAIL))
+			return 1;
 		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))