KVM: x86: hyper-v: Honor HV_MSR_TIME_REF_COUNT_AVAILABLE privilege bit

HV_X64_MSR_TIME_REF_COUNT is only available to guest when
HV_MSR_TIME_REF_COUNT_AVAILABLE bit is exposed.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210521095204.2161214-8-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/hyperv.c

@@ -1216,6 +1216,9 @@ static bool hv_check_msr_access(struct kvm_vcpu_hv *hv_vcpu, u32 msr)
 	case HV_X64_MSR_VP_RUNTIME:
 		return hv_vcpu->cpuid_cache.features_eax &
 			HV_MSR_VP_RUNTIME_AVAILABLE;
+	case HV_X64_MSR_TIME_REF_COUNT:
+		return hv_vcpu->cpuid_cache.features_eax &
+			HV_MSR_TIME_REF_COUNT_AVAILABLE;
 	default:
 		break;
 	}