diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 2ce09aa7d3b..2de335d7f63 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -101,9 +101,12 @@ struct kvm_userspace_memory_region {
 	__u64 userspace_addr; /* start of the userspace allocated memory */
 };
 
-/* for kvm_memory_region::flags */
+/*
+ * The bit 0 ~ bit 15 of kvm_memory_region::flags are visible for userspace,
+ * other bits are reserved for kvm internal use which are defined in
+ * include/linux/kvm_host.h.
+ */
 #define KVM_MEM_LOG_DIRTY_PAGES  1UL
-#define KVM_MEMSLOT_INVALID      (1UL << 1)
 
 /* for KVM_IRQ_LINE */
 struct kvm_irq_level {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index d2b897ee3ac..d4bd4d41e35 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -35,6 +35,13 @@
 #define KVM_MMIO_SIZE 8
 #endif
 
+/*
+ * The bit 16 ~ bit 31 of kvm_memory_region::flags are internally used
+ * in kvm, other bits are visible for userspace which are defined in
+ * include/linux/kvm_h.
+ */
+#define KVM_MEMSLOT_INVALID	(1UL << 16)
+
 /*
  * If we support unaligned MMIO, at most one fragment will be split into two:
  */