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FAILED: patch "[PATCH] KVM: SVM: Inject #GP on guest MSR_TSC_AUX accesses if RDTSCP" failed to apply to 4.9-stable tree

PATCH [email protected] 1 participant 1 message May 12, 2021

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The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 6f2b296aa6432d8274e258cc3220047ca04f5de0 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <[email protected]>
Date: Fri, 23 Apr 2021 15:34:01 -0700
Subject: [PATCH] KVM: SVM: Inject #GP on guest MSR_TSC_AUX accesses if RDTSCP
unsupported

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 [email protected]
Signed-off-by Sean Christopherson <[email protected]>

Message-Id: <[email protected]>

Reviewed-by Vitaly Kuznetsov <[email protected]>
Signed-off-by Paolo Bonzini <[email protected]>
arch/x86/kvm/svm/svm.c +7 -0
index cd8c333ed2dc..9ed9c7bd7cfd 100644
@@ -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