diff --git a/include/exec/memory.h b/include/exec/memory.h
index 2d9ea3c088acec1ecaeea392d31a4a86c69f5ecc..3e4d4164cd45a159c487d930a4df04d2f4653923 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -467,12 +467,9 @@ void memory_region_init_rom(MemoryRegion *mr,
  * memory_region_init_rom_device:  Initialize a ROM memory region.  Writes are
  *                                 handled via callbacks.
  *
- * If NULL callbacks pointer is given, then I/O space is not supposed to be
- * handled by QEMU itself. Any access via the memory API will cause an abort().
- *
  * @mr: the #MemoryRegion to be initialized.
  * @owner: the object that tracks the region's reference count
- * @ops: callbacks for write access handling.
+ * @ops: callbacks for write access handling (must not be NULL).
  * @name: the name of the region.
  * @size: size of the region.
  * @errp: pointer to Error*, to store an error if it happens.
diff --git a/memory.c b/memory.c
index ecb565ea8178527f6c9271515fd3d43c9f310371..0eb6895fe6a1535dd44a71e4b65221119b7df438 100644
--- a/memory.c
+++ b/memory.c
@@ -1399,6 +1399,7 @@ void memory_region_init_rom_device(MemoryRegion *mr,
                                    uint64_t size,
                                    Error **errp)
 {
+    assert(ops);
     memory_region_init(mr, owner, name, size);
     mr->ops = ops;
     mr->opaque = opaque;