KVM: x86: Track supported PERF_CAPABILITIES in kvm_caps

Track KVM's supported PERF_CAPABILITIES in kvm_caps instead of computing
the supported capabilities on the fly every time.  Using kvm_caps will
also allow for future cleanups as the kvm_caps values can be used
directly in common x86 code.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Acked-by: Like Xu <likexu@tencent.com>
Message-Id: <20221006000314.73240-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/svm/svm.c

@@ -2714,6 +2714,7 @@ static int svm_get_msr_feature(struct kvm_msr_entry *msr)
 			msr->data |= MSR_F10H_DECFG_LFENCE_SERIALIZE;
 		break;
 	case MSR_IA32_PERF_CAPABILITIES:
+		msr->data = kvm_caps.supported_perf_cap;
 		return 0;
 	default:
 		return KVM_MSR_RET_INVALID;
@@ -4865,6 +4866,7 @@ static __init void svm_set_cpu_caps(void)
 {
 	kvm_set_cpu_caps();
 
+	kvm_caps.supported_perf_cap = 0;
 	kvm_caps.supported_xss = 0;
 
 	/* CPUID 0x80000001 and 0x8000000A (SVM features) */

arch/x86/kvm/vmx/capabilities.h

@@ -395,31 +395,6 @@ static inline bool vmx_pebs_supported(void)
 	return boot_cpu_has(X86_FEATURE_PEBS) && kvm_pmu_cap.pebs_ept;
 }
 
-static inline u64 vmx_get_perf_capabilities(void)
-{
-	u64 perf_cap = PMU_CAP_FW_WRITES;
-	struct x86_pmu_lbr lbr;
-	u64 host_perf_cap = 0;
-
-	if (!enable_pmu)
-		return 0;
-
-	if (boot_cpu_has(X86_FEATURE_PDCM))
-		rdmsrl(MSR_IA32_PERF_CAPABILITIES, host_perf_cap);
-
-	x86_perf_get_lbr(&lbr);
-	if (lbr.nr)
-		perf_cap |= host_perf_cap & PMU_CAP_LBR_FMT;
-
-	if (vmx_pebs_supported()) {
-		perf_cap |= host_perf_cap & PERF_CAP_PEBS_MASK;
-		if ((perf_cap & PERF_CAP_PEBS_FORMAT) < 4)
-			perf_cap &= ~PERF_CAP_PEBS_BASELINE;
-	}
-
-	return perf_cap;
-}
-
 static inline bool cpu_has_notify_vmexit(void)
 {
 	return vmcs_config.cpu_based_2nd_exec_ctrl &

arch/x86/kvm/vmx/pmu_intel.c

@@ -631,7 +631,7 @@ static void intel_pmu_init(struct kvm_vcpu *vcpu)
 		pmu->fixed_counters[i].current_config = 0;
 	}
 
-	vcpu->arch.perf_capabilities = vmx_get_perf_capabilities();
+	vcpu->arch.perf_capabilities = kvm_caps.supported_perf_cap;
 	lbr_desc->records.nr = 0;
 	lbr_desc->event = NULL;
 	lbr_desc->msr_passthrough = false;

arch/x86/kvm/vmx/vmx.c

@@ -1850,7 +1850,7 @@ static int vmx_get_msr_feature(struct kvm_msr_entry *msr)
 			return 1;
 		return vmx_get_vmx_msr(&vmcs_config.nested, msr->index, &msr->data);
 	case MSR_IA32_PERF_CAPABILITIES:
-		msr->data = vmx_get_perf_capabilities();
+		msr->data = kvm_caps.supported_perf_cap;
 		return 0;
 	default:
 		return KVM_MSR_RET_INVALID;
@@ -2029,7 +2029,7 @@ static u64 vmx_get_supported_debugctl(struct kvm_vcpu *vcpu, bool host_initiated
 	    (host_initiated || guest_cpuid_has(vcpu, X86_FEATURE_BUS_LOCK_DETECT)))
 		debugctl |= DEBUGCTLMSR_BUS_LOCK_DETECT;
 
-	if ((vmx_get_perf_capabilities() & PMU_CAP_LBR_FMT) &&
+	if ((kvm_caps.supported_perf_cap & PMU_CAP_LBR_FMT) &&
 	    (host_initiated || intel_pmu_lbr_is_enabled(vcpu)))
 		debugctl |= DEBUGCTLMSR_LBR | DEBUGCTLMSR_FREEZE_LBRS_ON_PMI;
 
@@ -2342,14 +2342,14 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			return 1;
 		if (data & PMU_CAP_LBR_FMT) {
 			if ((data & PMU_CAP_LBR_FMT) !=
-			    (vmx_get_perf_capabilities() & PMU_CAP_LBR_FMT))
+			    (kvm_caps.supported_perf_cap & PMU_CAP_LBR_FMT))
 				return 1;
 			if (!cpuid_model_is_consistent(vcpu))
 				return 1;
 		}
 		if (data & PERF_CAP_PEBS_FORMAT) {
 			if ((data & PERF_CAP_PEBS_MASK) !=
-			    (vmx_get_perf_capabilities() & PERF_CAP_PEBS_MASK))
+			    (kvm_caps.supported_perf_cap & PERF_CAP_PEBS_MASK))
 				return 1;
 			if (!guest_cpuid_has(vcpu, X86_FEATURE_DS))
 				return 1;
@@ -7669,6 +7669,31 @@ static void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 	vmx_update_exception_bitmap(vcpu);
 }
 
+static u64 vmx_get_perf_capabilities(void)
+{
+	u64 perf_cap = PMU_CAP_FW_WRITES;
+	struct x86_pmu_lbr lbr;
+	u64 host_perf_cap = 0;
+
+	if (!enable_pmu)
+		return 0;
+
+	if (boot_cpu_has(X86_FEATURE_PDCM))
+		rdmsrl(MSR_IA32_PERF_CAPABILITIES, host_perf_cap);
+
+	x86_perf_get_lbr(&lbr);
+	if (lbr.nr)
+		perf_cap |= host_perf_cap & PMU_CAP_LBR_FMT;
+
+	if (vmx_pebs_supported()) {
+		perf_cap |= host_perf_cap & PERF_CAP_PEBS_MASK;
+		if ((perf_cap & PERF_CAP_PEBS_FORMAT) < 4)
+			perf_cap &= ~PERF_CAP_PEBS_BASELINE;
+	}
+
+	return perf_cap;
+}
+
 static __init void vmx_set_cpu_caps(void)
 {
 	kvm_set_cpu_caps();
@@ -7691,6 +7716,7 @@ static __init void vmx_set_cpu_caps(void)
 
 	if (!enable_pmu)
 		kvm_cpu_cap_clear(X86_FEATURE_PDCM);
+	kvm_caps.supported_perf_cap = vmx_get_perf_capabilities();
 
 	if (!enable_sgx) {
 		kvm_cpu_cap_clear(X86_FEATURE_SGX);

arch/x86/kvm/x86.h

@@ -27,6 +27,7 @@ struct kvm_caps {
 	u64 supported_mce_cap;
 	u64 supported_xcr0;
 	u64 supported_xss;
+	u64 supported_perf_cap;
 };
 
 void kvm_spurious_fault(void);