[PATCH RFC 08/22] KVM: x86: hyper-v: Honor HV_MSR_REFERENCE_TSC_AVAILABLE privilege bit

[Vitaly Kuznetsov]

HV_X64_MSR_REFERENCE_TSC is only available to guest when
HV_MSR_REFERENCE_TSC_AVAILABLE bit is exposed.

Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
---
 arch/x86/kvm/hyperv.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 15d557ce32b5..48215ad72b6c 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1257,6 +1257,10 @@ static int kvm_hv_set_msr_pw(struct kvm_vcpu *vcpu, u32 
msr, u64 data,
                break;
        }
        case HV_X64_MSR_REFERENCE_TSC:
+               if (unlikely(!host && !(hv_vcpu->cpuid_cache.features_eax &
+                                       HV_MSR_REFERENCE_TSC_AVAILABLE)))
+                       return 1;
+
                hv->hv_tsc_page = data;
                if (hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE) {
                        if (!host)
@@ -1478,6 +1482,10 @@ static int kvm_hv_get_msr_pw(struct kvm_vcpu *vcpu, u32 
msr, u64 *pdata,
                data = get_time_ref_counter(kvm);
                break;
        case HV_X64_MSR_REFERENCE_TSC:
+               if (unlikely(!host && !(hv_vcpu->cpuid_cache.features_eax &
+                                       HV_MSR_REFERENCE_TSC_AVAILABLE)))
+                       return 1;
+
                data = hv->hv_tsc_page;
                break;
        case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4:
-- 
2.30.2