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FAILED: patch "[PATCH] KVM: VMX: check CPUID before allowing read/write of IA32_XSS" failed to apply to 4.9-stable tree

PATCH [email protected] 1 participant 1 message Jul 23, 2019

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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 4d763b168e9c5c366b05812c7bba7662e5ea3669 Mon Sep 17 00:00:00 2001
From: Wanpeng Li <[email protected]>
Date: Thu, 20 Jun 2019 17:00:02 +0800
Subject: [PATCH] KVM: VMX: check CPUID before allowing read/write of IA32_XSS
MIME-Version: 1.0
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Raise #GP when guest read/write IA32_XSS, but the CPUID bits say that it shouldn't exist.

Fixes 203000993de5 (kvm: vmx: add MSR logic for XSAVES)
Reported-by Xiaoyao Li <[email protected]>
Reported-by Tao Xu <[email protected]>
Cc Paolo Bonzini <[email protected]>
Cc Radim Krčmář <[email protected]>
Cc [email protected]
Signed-off-by Wanpeng Li <[email protected]>
Signed-off-by Paolo Bonzini <[email protected]>
arch/x86/kvm/vmx/vmx.c +8 -2
index b939a688ae83..a35459ce7e29 100644
@@ -1732,7 +1732,10 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		return vmx_get_vmx_msr(&vmx->nested.msrs, msr_info->index,
 				       &msr_info->data);
 	case MSR_IA32_XSS:
-		if (!vmx_xsaves_supported())
+		if (!vmx_xsaves_supported() ||
+		    (!msr_info->host_initiated &&
+		     !(guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) &&
+		       guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))))
 			return 1;
 		msr_info->data = vcpu->arch.ia32_xss;
 		break;

@@ -1962,7 +1965,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			return 1;
 		return vmx_set_vmx_msr(vcpu, msr_index, data);
 	case MSR_IA32_XSS:
-		if (!vmx_xsaves_supported())
+		if (!vmx_xsaves_supported() ||
+		    (!msr_info->host_initiated &&
+		     !(guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) &&
+		       guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))))
 			return 1;
 		/*
 		 * The only supported bit as of Skylake is bit 8, but