KVM: Add API for determining the number of supported memory slots

Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 955d2ee..b7c32f6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -814,6 +814,9 @@
 	case KVM_CAP_NR_VCPUS:
 		r = KVM_MAX_VCPUS;
 		break;
+	case KVM_CAP_NR_MEMSLOTS:
+		r = KVM_MEMORY_SLOTS;
+		break;
 	default:
 		r = 0;
 		break;