[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20210413122630.975617-5-vkuznets@redhat.com>
Date: Tue, 13 Apr 2021 14:26:12 +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, linux-hyperv@...r.kernel.org
Subject: [PATCH RFC 04/22] 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.
Note, writing to HV_X64_MSR_TIME_REF_COUNT is unsupported so
kvm_hv_set_msr_pw() doesn't need an additional check.
Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
---
arch/x86/kvm/hyperv.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index b39445aabbc2..efb3d69c98fd 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1440,6 +1440,7 @@ static int kvm_hv_get_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata,
u64 data = 0;
struct kvm *kvm = vcpu->kvm;
struct kvm_hv *hv = to_kvm_hv(kvm);
+ struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
switch (msr) {
case HV_X64_MSR_GUEST_OS_ID:
@@ -1449,6 +1450,10 @@ static int kvm_hv_get_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata,
data = hv->hv_hypercall;
break;
case HV_X64_MSR_TIME_REF_COUNT:
+ if (unlikely(!host && !(hv_vcpu->cpuid_cache.features_eax &
+ HV_MSR_TIME_REF_COUNT_AVAILABLE)))
+ return 1;
+
data = get_time_ref_counter(kvm);
break;
case HV_X64_MSR_REFERENCE_TSC:
--
2.30.2
Powered by blists - more mailing lists