linux-kernel - [PATCH v2 12/30] KVM: x86: hyper-v: Honor HV_MSR_SYNTIMER

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Date:   Fri, 21 May 2021 11:51:46 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     kvm@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Siddharth Chandrasekaran <sidcha@...zon.de>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 12/30] KVM: x86: hyper-v: Honor HV_MSR_SYNTIMER_AVAILABLE privilege bit

Synthetic timers MSRs (HV_X64_MSR_STIMER[0-3]_CONFIG,
HV_X64_MSR_STIMER[0-3]_COUNT) are only available to guest when
HV_MSR_SYNTIMER_AVAILABLE bit is exposed.

Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
---
 arch/x86/kvm/hyperv.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 17bdf8e8196e..2582c23126fa 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1227,6 +1227,16 @@ static bool hv_check_msr_access(struct kvm_vcpu_hv *hv_vcpu, u32 msr)
 	case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
 		return hv_vcpu->cpuid_cache.features_eax &
 			HV_MSR_SYNIC_AVAILABLE;
+	case HV_X64_MSR_STIMER0_CONFIG:
+	case HV_X64_MSR_STIMER1_CONFIG:
+	case HV_X64_MSR_STIMER2_CONFIG:
+	case HV_X64_MSR_STIMER3_CONFIG:
+	case HV_X64_MSR_STIMER0_COUNT:
+	case HV_X64_MSR_STIMER1_COUNT:
+	case HV_X64_MSR_STIMER2_COUNT:
+	case HV_X64_MSR_STIMER3_COUNT:
+		return hv_vcpu->cpuid_cache.features_eax &
+			HV_MSR_SYNTIMER_AVAILABLE;
 	default:
 		break;
 	}
-- 
2.31.1