[PATCH 17/30] KVM: x86: hyper-v: Honor HV_FEATURE_DEBUG_MSRS_AVAILABLE privilege bit

[Vitaly Kuznetsov]

Synthetic debugging MSRs (HV_X64_MSR_SYNDBG_CONTROL,
HV_X64_MSR_SYNDBG_STATUS, HV_X64_MSR_SYNDBG_SEND_BUFFER,
HV_X64_MSR_SYNDBG_RECV_BUFFER, HV_X64_MSR_SYNDBG_PENDING_BUFFER,
HV_X64_MSR_SYNDBG_OPTIONS) are only available to guest when
HV_FEATURE_DEBUG_MSRS_AVAILABLE bit is exposed.

Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
---
 arch/x86/kvm/hyperv.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 43ebb53b6b38..f54385ffcdc0 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1257,6 +1257,10 @@ static bool hv_check_msr_access(struct kvm_vcpu_hv 
*hv_vcpu, u32 msr)
        case HV_X64_MSR_CRASH_CTL:
                return hv_vcpu->cpuid_cache.features_edx &
                        HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE;
+       case HV_X64_MSR_SYNDBG_OPTIONS:
+       case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
+               return hv_vcpu->cpuid_cache.features_edx &
+                       HV_FEATURE_DEBUG_MSRS_AVAILABLE;
        default:
                break;
        }
-- 
2.30.2