linux-kernel - [PATCH 5.12 117/677] KVM: SVM: Inject #GP on guest MSR_TSC

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Date:   Wed, 12 May 2021 16:42:43 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: [PATCH 5.12 117/677] KVM: SVM: Inject #GP on guest MSR_TSC_AUX accesses if RDTSCP unsupported

From: Sean Christopherson <seanjc@...gle.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@...r.kernel.org
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
Message-Id: <20210423223404.3860547-2-seanjc@...gle.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@...hat.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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
@@ -2738,6 +2738,9 @@ 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;
 	/*
@@ -2946,6 +2949,10 @@ 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