KVM: X86: Report SVM bit to userspace only when supported

This patch fixes a bug in KVM where it _always_ reports the
support of the SVM feature to userspace. But KVM only
supports SVM on AMD hardware and only when it is enabled in
the kernel module. This patch fixes the wrong reporting.

Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 36e6c88913d..e0f4da07f98 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3469,6 +3469,10 @@ static void svm_cpuid_update(struct kvm_vcpu *vcpu)
 static void svm_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry)
 {
         switch (func) {
+        case 0x80000001:
+                if (nested)
+                        entry->ecx |= (1 << 2); /* Set SVM bit */
+                break;
         case 0x8000000A:
                 entry->eax = 1; /* SVM revision 1 */
                 entry->ebx = 8; /* Lets support 8 ASIDs in case we add proper