diff --git a/docs/devel/qom.rst b/docs/devel/qom.rst
index 9918fac7f21..0889ca949c1 100644
--- a/docs/devel/qom.rst
+++ b/docs/devel/qom.rst
@@ -348,12 +348,14 @@ used. This does the same as OBJECT_DECLARE_SIMPLE_TYPE(), but without
 the 'struct MyDeviceClass' definition.
 
 To implement the type, the OBJECT_DEFINE macro family is available.
-In the simple case the OBJECT_DEFINE_TYPE macro is suitable:
+For the simplest case of a leaf class which doesn't need any of its
+own virtual functions (i.e. which was declared with OBJECT_DECLARE_SIMPLE_TYPE)
+the OBJECT_DEFINE_SIMPLE_TYPE macro is suitable:
 
 .. code-block:: c
    :caption: Defining a simple type
 
-   OBJECT_DEFINE_TYPE(MyDevice, my_device, MY_DEVICE, DEVICE)
+   OBJECT_DEFINE_SIMPLE_TYPE(MyDevice, my_device, MY_DEVICE, DEVICE)
 
 This is equivalent to the following:
 
@@ -370,7 +372,6 @@ This is equivalent to the following:
        .instance_size = sizeof(MyDevice),
        .instance_init = my_device_init,
        .instance_finalize = my_device_finalize,
-       .class_size = sizeof(MyDeviceClass),
        .class_init = my_device_class_init,
    };
 
@@ -385,13 +386,36 @@ This is sufficient to get the type registered with the type
 system, and the three standard methods now need to be implemented
 along with any other logic required for the type.
 
+If the class needs its own virtual methods, or has some other
+per-class state it needs to store in its own class struct,
+then you can use the OBJECT_DEFINE_TYPE macro. This does the
+same thing as OBJECT_DEFINE_SIMPLE_TYPE, but it also sets the
+class_size of the type to the size of the class struct.
+
+.. code-block:: c
+   :caption: Defining a type which needs a class struct
+
+   OBJECT_DEFINE_TYPE(MyDevice, my_device, MY_DEVICE, DEVICE)
+
 If the type needs to implement one or more interfaces, then the
-OBJECT_DEFINE_TYPE_WITH_INTERFACES() macro can be used instead.
-This accepts an array of interface type names.
+OBJECT_DEFINE_SIMPLE_TYPE_WITH_INTERFACES() and
+OBJECT_DEFINE_TYPE_WITH_INTERFACES() macros can be used instead.
+These accept an array of interface type names. The difference between
+them is that the former is for simple leaf classes that don't need
+a class struct, and the latter is for when you will be defining
+a class struct.
 
 .. code-block:: c
    :caption: Defining a simple type implementing interfaces
 
+   OBJECT_DEFINE_SIMPLE_TYPE_WITH_INTERFACES(MyDevice, my_device,
+                                             MY_DEVICE, DEVICE,
+                                             { TYPE_USER_CREATABLE },
+                                             { NULL })
+
+.. code-block:: c
+   :caption: Defining a type implementing interfaces
+
    OBJECT_DEFINE_TYPE_WITH_INTERFACES(MyDevice, my_device,
                                       MY_DEVICE, DEVICE,
                                       { TYPE_USER_CREATABLE },
diff --git a/include/qom/object.h b/include/qom/object.h
index e9ed9550f05..13d3a655ddf 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -258,6 +258,51 @@ struct Object
     DECLARE_INSTANCE_CHECKER(InstanceType, MODULE_OBJ_NAME, TYPE_##MODULE_OBJ_NAME)
 
 
+/**
+ * DO_OBJECT_DEFINE_TYPE_EXTENDED:
+ * @ModuleObjName: the object name with initial caps
+ * @module_obj_name: the object name in lowercase with underscore separators
+ * @MODULE_OBJ_NAME: the object name in uppercase with underscore separators
+ * @PARENT_MODULE_OBJ_NAME: the parent object name in uppercase with underscore
+ *                          separators
+ * @ABSTRACT: boolean flag to indicate whether the object can be instantiated
+ * @CLASS_SIZE: size of the type's class
+ * @...: list of initializers for "InterfaceInfo" to declare implemented interfaces
+ *
+ * This is the base macro used to implement all the OBJECT_DEFINE_*
+ * macros. It should never be used directly in a source file.
+ */
+#define DO_OBJECT_DEFINE_TYPE_EXTENDED(ModuleObjName, module_obj_name, \
+                                       MODULE_OBJ_NAME, \
+                                       PARENT_MODULE_OBJ_NAME, \
+                                       ABSTRACT, CLASS_SIZE, ...) \
+    static void \
+    module_obj_name##_finalize(Object *obj); \
+    static void \
+    module_obj_name##_class_init(ObjectClass *oc, void *data); \
+    static void \
+    module_obj_name##_init(Object *obj); \
+    \
+    static const TypeInfo module_obj_name##_info = { \
+        .parent = TYPE_##PARENT_MODULE_OBJ_NAME, \
+        .name = TYPE_##MODULE_OBJ_NAME, \
+        .instance_size = sizeof(ModuleObjName), \
+        .instance_align = __alignof__(ModuleObjName), \
+        .instance_init = module_obj_name##_init, \
+        .instance_finalize = module_obj_name##_finalize, \
+        .class_size = CLASS_SIZE, \
+        .class_init = module_obj_name##_class_init, \
+        .abstract = ABSTRACT, \
+        .interfaces = (InterfaceInfo[]) { __VA_ARGS__ } , \
+    }; \
+    \
+    static void \
+    module_obj_name##_register_types(void) \
+    { \
+        type_register_static(&module_obj_name##_info); \
+    } \
+    type_init(module_obj_name##_register_types);
+
 /**
  * OBJECT_DEFINE_TYPE_EXTENDED:
  * @ModuleObjName: the object name with initial caps
@@ -284,32 +329,10 @@ struct Object
 #define OBJECT_DEFINE_TYPE_EXTENDED(ModuleObjName, module_obj_name, \
                                     MODULE_OBJ_NAME, PARENT_MODULE_OBJ_NAME, \
                                     ABSTRACT, ...) \
-    static void \
-    module_obj_name##_finalize(Object *obj); \
-    static void \
-    module_obj_name##_class_init(ObjectClass *oc, void *data); \
-    static void \
-    module_obj_name##_init(Object *obj); \
-    \
-    static const TypeInfo module_obj_name##_info = { \
-        .parent = TYPE_##PARENT_MODULE_OBJ_NAME, \
-        .name = TYPE_##MODULE_OBJ_NAME, \
-        .instance_size = sizeof(ModuleObjName), \
-        .instance_align = __alignof__(ModuleObjName), \
-        .instance_init = module_obj_name##_init, \
-        .instance_finalize = module_obj_name##_finalize, \
-        .class_size = sizeof(ModuleObjName##Class), \
-        .class_init = module_obj_name##_class_init, \
-        .abstract = ABSTRACT, \
-        .interfaces = (InterfaceInfo[]) { __VA_ARGS__ } , \
-    }; \
-    \
-    static void \
-    module_obj_name##_register_types(void) \
-    { \
-        type_register_static(&module_obj_name##_info); \
-    } \
-    type_init(module_obj_name##_register_types);
+    DO_OBJECT_DEFINE_TYPE_EXTENDED(ModuleObjName, module_obj_name, \
+                                   MODULE_OBJ_NAME, PARENT_MODULE_OBJ_NAME, \
+                                   ABSTRACT, sizeof(ModuleObjName##Class), \
+                                   __VA_ARGS__)
 
 /**
  * OBJECT_DEFINE_TYPE:
@@ -368,6 +391,45 @@ struct Object
                                 MODULE_OBJ_NAME, PARENT_MODULE_OBJ_NAME, \
                                 true, { NULL })
 
+/**
+ * OBJECT_DEFINE_SIMPLE_TYPE_WITH_INTERFACES:
+ * @ModuleObjName: the object name with initial caps
+ * @module_obj_name: the object name in lowercase with underscore separators
+ * @MODULE_OBJ_NAME: the object name in uppercase with underscore separators
+ * @PARENT_MODULE_OBJ_NAME: the parent object name in uppercase with underscore
+ *                          separators
+ *
+ * This is a variant of OBJECT_DEFINE_TYPE_EXTENDED, which is suitable for
+ * the case of a non-abstract type, with interfaces, and with no requirement
+ * for a class struct.
+ */
+#define OBJECT_DEFINE_SIMPLE_TYPE_WITH_INTERFACES(ModuleObjName, \
+                                                  module_obj_name, \
+                                                  MODULE_OBJ_NAME, \
+                                                  PARENT_MODULE_OBJ_NAME, ...) \
+    DO_OBJECT_DEFINE_TYPE_EXTENDED(ModuleObjName, module_obj_name, \
+                                   MODULE_OBJ_NAME, PARENT_MODULE_OBJ_NAME, \
+                                   false, 0, __VA_ARGS__)
+
+/**
+ * OBJECT_DEFINE_SIMPLE_TYPE:
+ * @ModuleObjName: the object name with initial caps
+ * @module_obj_name: the object name in lowercase with underscore separators
+ * @MODULE_OBJ_NAME: the object name in uppercase with underscore separators
+ * @PARENT_MODULE_OBJ_NAME: the parent object name in uppercase with underscore
+ *                          separators
+ *
+ * This is a variant of OBJECT_DEFINE_TYPE_EXTENDED, which is suitable for
+ * the common case of a non-abstract type, without any interfaces, and with
+ * no requirement for a class struct. If you declared your type with
+ * OBJECT_DECLARE_SIMPLE_TYPE then this is probably the right choice for
+ * defining it.
+ */
+#define OBJECT_DEFINE_SIMPLE_TYPE(ModuleObjName, module_obj_name, \
+                                  MODULE_OBJ_NAME, PARENT_MODULE_OBJ_NAME) \
+    OBJECT_DEFINE_SIMPLE_TYPE_WITH_INTERFACES(ModuleObjName, module_obj_name, \
+        MODULE_OBJ_NAME, PARENT_MODULE_OBJ_NAME, { NULL })
+
 /**
  * struct TypeInfo:
  * @name: The name of the type.
