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

Signed-off-by: Avi Kivity <avi@qumranet.com>

arch/x86/kvm/x86.c

@@ -814,6 +814,9 @@ int kvm_dev_ioctl_check_extension(long ext)
 	case KVM_CAP_NR_VCPUS:
 		r = KVM_MAX_VCPUS;
 		break;
+	case KVM_CAP_NR_MEMSLOTS:
+		r = KVM_MEMORY_SLOTS;
+		break;
 	default:
 		r = 0;
 		break;

include/linux/kvm.h

@@ -235,6 +235,7 @@ struct kvm_vapic_addr {
 #define KVM_CAP_EXT_CPUID 7
 #define KVM_CAP_CLOCKSOURCE 8
 #define KVM_CAP_NR_VCPUS 9       /* returns max vcpus per vm */
+#define KVM_CAP_NR_MEMSLOTS 10   /* returns max memory slots per vm */
 
 /*
  * ioctls for VM fds