From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Wed, 19 Dec 2018 11:06:13 +0000 (+0100)
Subject: KVM: x86: svm: report MSR_IA32_MCG_EXT_CTL as unsupported
X-Git-Tag: v4.9.156~60
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3b3db169bf10d34fb7d3852c5222c925e3952269;p=thirdparty%2Fkernel%2Fstable.git

KVM: x86: svm: report MSR_IA32_MCG_EXT_CTL as unsupported

[ Upstream commit e87555e550cef4941579cd879759a7c0dee24e68 ]

AMD doesn't seem to implement MSR_IA32_MCG_EXT_CTL and svm code in kvm
knows nothing about it, however, this MSR is among emulated_msrs and
thus returned with KVM_GET_MSR_INDEX_LIST. The consequent KVM_GET_MSRS,
of course, fails.

Report the MSR as unsupported to not confuse userspace.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index fa1b0e3c8a068..c8efacf2e65f1 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -5223,6 +5223,13 @@ static bool svm_cpu_has_accelerated_tpr(void)
 
 static bool svm_has_emulated_msr(int index)
 {
+	switch (index) {
+	case MSR_IA32_MCG_EXT_CTL:
+		return false;
+	default:
+		break;
+	}
+
 	return true;
 }