KVM: Make EFER reads safe when EFER does not exist

Some processors don't have EFER; don't oops if userspace wants us to read EFER when we check NX. Cc: stable@kernel.org Signed-off-by: Avi Kivity <avi@redhat.com>
mariux64 · May 11, 2009 · e286e86 · e286e86
1 parent 334b8ad
commit e286e86
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
@@ -1121,9 +1121,9 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 
 static int is_efer_nx(void)
 {
-	u64 efer;
+	unsigned long long efer = 0;
 
-	rdmsrl(MSR_EFER, efer);
+	rdmsrl_safe(MSR_EFER, &efer);
 	return efer & EFER_NX;
 }