KVM: SVM: Emulate PERF_CNTR_GLOBAL_STATUS_SET for PerfMonV2

Emulate PERF_CNTR_GLOBAL_STATUS_SET when PerfMonV2 is enumerated to the
guest, as the MSR is supposed to exist in all AMD v2 PMUs.

Fixes: 4a27718 ("KVM: x86/svm/pmu: Add AMD PerfMonV2 support")
Cc: stable@vger.kernel.org
Cc: Sandipan Das <sandipan.das@amd.com>
Link: https://lore.kernel.org/r/20250711172746.1579423-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: sean-jc

arch/x86/include/asm/msr-index.h

@@ -733,6 +733,7 @@
 #define MSR_AMD64_PERF_CNTR_GLOBAL_STATUS	0xc0000300
 #define MSR_AMD64_PERF_CNTR_GLOBAL_CTL		0xc0000301
 #define MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR	0xc0000302
+#define MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_SET	0xc0000303
 
 /* AMD Hardware Feedback Support MSRs */
 #define MSR_AMD_WORKLOAD_CLASS_CONFIG		0xc0000500

arch/x86/kvm/pmu.c

@@ -650,6 +650,7 @@ int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		msr_info->data = pmu->global_ctrl;
 		break;
 	case MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR:
+	case MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_SET:
 	case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
 		msr_info->data = 0;
 		break;
@@ -711,6 +712,10 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		if (!msr_info->host_initiated)
 			pmu->global_status &= ~data;
 		break;
+	case MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_SET:
+		if (!msr_info->host_initiated)
+			pmu->global_status |= data & ~pmu->global_status_rsvd;
+		break;
 	default:
 		kvm_pmu_mark_pmc_in_use(vcpu, msr_info->index);
 		return kvm_pmu_call(set_msr)(vcpu, msr_info);

arch/x86/kvm/svm/pmu.c

@@ -113,6 +113,7 @@ static bool amd_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
 	case MSR_AMD64_PERF_CNTR_GLOBAL_STATUS:
 	case MSR_AMD64_PERF_CNTR_GLOBAL_CTL:
 	case MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR:
+	case MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_SET:
 		return pmu->version > 1;
 	default:
 		if (msr > MSR_F15H_PERF_CTR5 &&

arch/x86/kvm/x86.c

@@ -367,6 +367,7 @@ static const u32 msrs_to_save_pmu[] = {
 	MSR_AMD64_PERF_CNTR_GLOBAL_CTL,
 	MSR_AMD64_PERF_CNTR_GLOBAL_STATUS,
 	MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR,
+	MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_SET,
 };
 
 static u32 msrs_to_save[ARRAY_SIZE(msrs_to_save_base) +
@@ -7353,6 +7354,7 @@ static void kvm_probe_msr_to_save(u32 msr_index)
 	case MSR_AMD64_PERF_CNTR_GLOBAL_CTL:
 	case MSR_AMD64_PERF_CNTR_GLOBAL_STATUS:
 	case MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR:
+	case MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_SET:
 		if (!kvm_cpu_cap_has(X86_FEATURE_PERFMON_V2))
 			return;
 		break;