[PATCH 5.11 104/601] KVM: SVM: Inject #GP on guest MSR_TSC_AUX accesses if RDTSCP unsupported

Greg Kroah-Hartman
2021-05-12T17:02:22Z

From: Sean Christopherson <seanjc@google.com>

commit 6f2b296aa6432d8274e258cc3220047ca04f5de0 upstream.

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>
Message-Id: <20210423223404.3860547-2-seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kvm/svm/svm.c | 7 +++++++
1 file changed, 7 insertions(+)

--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2651,6 +2651,9 @@ static int svm_get_msr(struct kvm_vcpu *
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;
/*
@@ -2859,6 +2862,10 @@ static int svm_set_msr(struct kvm_vcpu *
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