[PATCH 4.14 132/205] KVM: x86: svm: report MSR_IA32_MCG_EXT_CTL as unsupported

Greg Kroah-Hartman
2019-02-11T15:00:28Z

[ 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>
---
arch/x86/kvm/svm.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 4dc79d139810..656ac12f5439 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -5319,6 +5319,13 @@ 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;
}

--
2.19.1