[PATCH v3 1/4] KVM: SVM: Inject #GP on guest MSR_TSC_AUX accesses if RDTSCP unsupported

Sean Christopherson
2021-04-23T22:34:34Z

Inject #GP on guest accesses to MSR_TSC_AUX if RDTSCP is unsupported in
the guest's CPUID model.

Fixes: 46896c73c1a4 ("KVM: svm: add support for RDTSCP")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/svm/svm.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index cd8c333ed2dc..9ed9c7bd7cfd 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2674,6 +2674,9 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_TSC_AUX:
if (!boot_cpu_has(X86_FEATURE_RDTSCP))
return 1;
+ if (!msr_info->host_initiated &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP))
+ return 1;
msr_info->data = svm->tsc_aux;
break;
/*
@@ -2892,6 +2895,10 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
if (!boot_cpu_has(X86_FEATURE_RDTSCP))
return 1;

+ if (!msr->host_initiated &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP))
+ return 1;
+
/*
* This is rare, so we update the MSR here instead of using
* direct_access_msrs. Doing that would require a rdmsr in
--
2.31.1.498.g6c1eba8ee3d-goog