KVM: x86: Directly query supported PERF_CAPABILITIES for WRMSR checks

Use kvm_caps.supported_perf_cap directly instead of bouncing through
kvm_get_msr_feature() when checking the incoming value for writes to
PERF_CAPABILITIES.

Note, kvm_get_msr_feature() is guaranteed to succeed when getting
PERF_CAPABILITIES, i.e. dropping that check is a nop.

No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221006000314.73240-9-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/x86.c

@@ -3563,20 +3563,15 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			return 1;
 		vcpu->arch.arch_capabilities = data;
 		break;
-	case MSR_IA32_PERF_CAPABILITIES: {
-		struct kvm_msr_entry msr_ent = {.index = msr, .data = 0};
-
+	case MSR_IA32_PERF_CAPABILITIES:
 		if (!msr_info->host_initiated)
 			return 1;
-		if (kvm_get_msr_feature(&msr_ent))
-			return 1;
-		if (data & ~msr_ent.data)
+		if (data & ~kvm_caps.supported_perf_cap)
 			return 1;
 
 		vcpu->arch.perf_capabilities = data;
 		kvm_pmu_refresh(vcpu);
 		return 0;
-	}
 	case MSR_EFER:
 		return set_efer(vcpu, msr_info);
 	case MSR_K7_HWCR: