KVM: VMX: Check for automatic switch msr table overflow

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d0d4afa..6e28d58 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1280,7 +1280,11 @@
 		if (m->guest[i].index == msr)
 			break;
 
-	if (i == m->nr) {
+	if (i == NR_AUTOLOAD_MSRS) {
+		printk_once(KERN_WARNING"Not enough mst switch entries. "
+				"Can't add msr %x\n", msr);
+		return;
+	} else if (i == m->nr) {
 		++m->nr;
 		vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->nr);
 		vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->nr);