Merge remote-tracking branch 'remotes/afaerber/tags/qom-devices-for-peter' into staging

QOM infrastructure fixes and device conversions

* Fix for properties on objects > 4 GiB
* Performance improvements for QOM property handling
* Assertion cleanups
* MAINTAINERS additions

# gpg: Signature made Thu 19 Nov 2015 14:32:16 GMT using RSA key ID 3E7E013F
# gpg: Good signature from "Andreas Färber <afaerber@suse.de>"
# gpg:                 aka "Andreas Färber <afaerber@suse.com>"

* remotes/afaerber/tags/qom-devices-for-peter:
  MAINTAINERS: Add check-qom-{interface,proplist} to QOM
  qom: Clean up assertions to display values on failure
  qom: Replace object property list with GHashTable
  qom: Add a test case for complex property finalization
  net: Convert net filter code to use object property iterators
  ppc: Convert spapr code to use object property iterators
  vl: Convert machine help code to use object property iterators
  qmp: Convert QMP code to use object property iterators
  qom: Introduce ObjectPropertyIterator struct for iteration
  qdev: Change Property::offset field to ptrdiff_t type

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

9 files changed, 388 insertions, 53 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 9e1fa72..28f0139 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1164,6 +1164,8 @@ F: include/qom/
 X: include/qom/cpu.h
 F: qom/
 X: qom/cpu.c
+F: tests/check-qom-interface.c
+F: tests/check-qom-proplist.c
 F: tests/qom-test.c
 
 QMP
diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c
index 5d6ea7c..f34bc04 100644
--- a/hw/ppc/spapr_drc.c
+++ b/hw/ppc/spapr_drc.c
@@ -657,6 +657,7 @@ int spapr_drc_populate_dt(void *fdt, int fdt_offset, Object *owner,
 {
     Object *root_container;
     ObjectProperty *prop;
+    ObjectPropertyIterator *iter;
     uint32_t drc_count = 0;
     GArray *drc_indexes, *drc_power_domains;
     GString *drc_names, *drc_types;
@@ -680,7 +681,8 @@ int spapr_drc_populate_dt(void *fdt, int fdt_offset, Object *owner,
      */
     root_container = container_get(object_get_root(), DRC_CONTAINER_PATH);
 
-    QTAILQ_FOREACH(prop, &root_container->properties, node) {
+    iter = object_property_iter_init(root_container);
+    while ((prop = object_property_iter_next(iter))) {
         Object *obj;
         sPAPRDRConnector *drc;
         sPAPRDRConnectorClass *drck;
@@ -721,6 +723,7 @@ int spapr_drc_populate_dt(void *fdt, int fdt_offset, Object *owner,
                                     spapr_drc_get_type_str(drc->type));
         drc_types = g_string_insert_len(drc_types, -1, "\0", 1);
     }
+    object_property_iter_free(iter);
 
     /* now write the drc count into the space we reserved at the
      * beginning of the arrays previously
diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index e6dbde4..c537969 100644
--- a/include/hw/qdev-core.h
+++ b/include/hw/qdev-core.h
@@ -237,7 +237,7 @@ struct BusState {
 struct Property {
     const char   *name;
     PropertyInfo *info;
-    int          offset;
+    ptrdiff_t    offset;
     uint8_t      bitnr;
     qtype_code   qtype;
     int64_t      defval;
diff --git a/include/qom/object.h b/include/qom/object.h
index 0bb89d4..f172fea 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -344,8 +344,6 @@ typedef struct ObjectProperty
     ObjectPropertyResolve *resolve;
     ObjectPropertyRelease *release;
     void *opaque;
-
-    QTAILQ_ENTRY(ObjectProperty) node;
 } ObjectProperty;
 
 /**
@@ -405,7 +403,7 @@ struct Object
     /*< private >*/
     ObjectClass *class;
     ObjectFree *free;
-    QTAILQ_HEAD(, ObjectProperty) properties;
+    GHashTable *properties;
     uint32_t ref;
     Object *parent;
 };
@@ -960,6 +958,55 @@ void object_property_del(Object *obj, const char *name, Error **errp);
 ObjectProperty *object_property_find(Object *obj, const char *name,
                                      Error **errp);
 
+typedef struct ObjectPropertyIterator ObjectPropertyIterator;
+
+/**
+ * object_property_iter_init:
+ * @obj: the object
+ *
+ * Initializes an iterator for traversing all properties
+ * registered against an object instance.
+ *
+ * It is forbidden to modify the property list while iterating,
+ * whether removing or adding properties.
+ *
+ * Typical usage pattern would be
+ *
+ * <example>
+ *   <title>Using object property iterators</title>
+ *   <programlisting>
+ *   ObjectProperty *prop;
+ *   ObjectPropertyIterator *iter;
+ *
+ *   iter = object_property_iter_init(obj);
+ *   while ((prop = object_property_iter_next(iter))) {
+ *     ... do something with prop ...
+ *   }
+ *   object_property_iter_free(iter);
+ *   </programlisting>
+ * </example>
+ *
+ * Returns: the new iterator
+ */
+ObjectPropertyIterator *object_property_iter_init(Object *obj);
+
+/**
+ * object_property_iter_free:
+ * @iter: the iterator instance
+ *
+ * Releases any resources associated with the iterator.
+ */
+void object_property_iter_free(ObjectPropertyIterator *iter);
+
+/**
+ * object_property_iter_next:
+ * @iter: the iterator instance
+ *
+ * Returns: the next property, or %NULL when all properties
+ * have been traversed.
+ */
+ObjectProperty *object_property_iter_next(ObjectPropertyIterator *iter);
+
 void object_unparent(Object *obj);
 
 /**
@@ -1488,6 +1535,9 @@ void object_property_set_description(Object *obj, const char *name,
  * Call @fn passing each child of @obj and @opaque to it, until @fn returns
  * non-zero.
  *
+ * It is forbidden to add or remove children from @obj from the @fn
+ * callback.
+ *
  * Returns: The last value returned by @fn, or 0 if there is no child.
  */
 int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
@@ -1503,6 +1553,9 @@ int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
  * non-zero. Calls recursively, all child nodes of @obj will also be passed
  * all the way down to the leaf nodes of the tree. Depth first ordering.
  *
+ * It is forbidden to add or remove children from @obj (or its
+ * child nodes) from the @fn callback.
+ *
  * Returns: The last value returned by @fn, or 0 if there is no child.
  */
 int object_child_foreach_recursive(Object *obj,
diff --git a/net/filter.c b/net/filter.c
index 326f2b5..1365bad 100644
--- a/net/filter.c
+++ b/net/filter.c
@@ -137,6 +137,7 @@ static void netfilter_complete(UserCreatable *uc, Error **errp)
     Error *local_err = NULL;
     char *str, *info;
     ObjectProperty *prop;
+    ObjectPropertyIterator *iter;
     StringOutputVisitor *ov;
 
     if (!nf->netdev_id) {
@@ -173,7 +174,8 @@ static void netfilter_complete(UserCreatable *uc, Error **errp)
     QTAILQ_INSERT_TAIL(&nf->netdev->filters, nf, next);
 
     /* generate info str */
-    QTAILQ_FOREACH(prop, &OBJECT(nf)->properties, node) {
+    iter = object_property_iter_init(OBJECT(nf));
+    while ((prop = object_property_iter_next(iter))) {
         if (!strcmp(prop->name, "type")) {
             continue;
         }
@@ -187,6 +189,7 @@ static void netfilter_complete(UserCreatable *uc, Error **errp)
         g_free(str);
         g_free(info);
     }
+    object_property_iter_free(iter);
 }
 
 static void netfilter_finalize(Object *obj)
diff --git a/qmp.c b/qmp.c
index ddc63ea..0a1fa19 100644
--- a/qmp.c
+++ b/qmp.c
@@ -210,6 +210,7 @@ ObjectPropertyInfoList *qmp_qom_list(const char *path, Error **errp)
     bool ambiguous = false;
     ObjectPropertyInfoList *props = NULL;
     ObjectProperty *prop;
+    ObjectPropertyIterator *iter;
 
     obj = object_resolve_path(path, &ambiguous);
     if (obj == NULL) {
@@ -222,7 +223,8 @@ ObjectPropertyInfoList *qmp_qom_list(const char *path, Error **errp)
         return NULL;
     }
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
+    iter = object_property_iter_init(obj);
+    while ((prop = object_property_iter_next(iter))) {
         ObjectPropertyInfoList *entry = g_malloc0(sizeof(*entry));
 
         entry->value = g_malloc0(sizeof(ObjectPropertyInfo));
@@ -232,6 +234,7 @@ ObjectPropertyInfoList *qmp_qom_list(const char *path, Error **errp)
         entry->value->name = g_strdup(prop->name);
         entry->value->type = g_strdup(prop->type);
     }
+    object_property_iter_free(iter);
 
     return props;
 }
@@ -503,6 +506,7 @@ DevicePropertyInfoList *qmp_device_list_properties(const char *typename,
     ObjectClass *klass;
     Object *obj;
     ObjectProperty *prop;
+    ObjectPropertyIterator *iter;
     DevicePropertyInfoList *prop_list = NULL;
 
     klass = object_class_by_name(typename);
@@ -531,7 +535,8 @@ DevicePropertyInfoList *qmp_device_list_properties(const char *typename,
 
     obj = object_new(typename);
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
+    iter = object_property_iter_init(obj);
+    while ((prop = object_property_iter_next(iter))) {
         DevicePropertyInfo *info;
         DevicePropertyInfoList *entry;
 
@@ -562,6 +567,7 @@ DevicePropertyInfoList *qmp_device_list_properties(const char *typename,
         entry->next = prop_list;
         prop_list = entry;
     }
+    object_property_iter_free(iter);
 
     object_unref(obj);
 
diff --git a/qom/object.c b/qom/object.c
index c0decb6..d751569 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -67,6 +67,10 @@ struct TypeImpl
     InterfaceImpl interfaces[MAX_INTERFACES];
 };
 
+struct ObjectPropertyIterator {
+    GHashTableIter iter;
+};
+
 static Type type_interface;
 
 static GHashTable *type_table_get(void)
@@ -261,7 +265,7 @@ static void type_initialize(TypeImpl *ti)
         GSList *e;
         int i;
 
-        g_assert(parent->class_size <= ti->class_size);
+        g_assert_cmpint(parent->class_size, <=, ti->class_size);
         memcpy(ti->class, parent->class, parent->class_size);
         ti->class->interfaces = NULL;
 
@@ -326,6 +330,16 @@ static void object_post_init_with_type(Object *obj, TypeImpl *ti)
     }
 }
 
+static void object_property_free(gpointer data)
+{
+    ObjectProperty *prop = data;
+
+    g_free(prop->name);
+    g_free(prop->type);
+    g_free(prop->description);
+    g_free(prop);
+}
+
 void object_initialize_with_type(void *data, size_t size, TypeImpl *type)
 {
     Object *obj = data;
@@ -333,14 +347,15 @@ void object_initialize_with_type(void *data, size_t size, TypeImpl *type)
     g_assert(type != NULL);
     type_initialize(type);
 
-    g_assert(type->instance_size >= sizeof(Object));
+    g_assert_cmpint(type->instance_size, >=, sizeof(Object));
     g_assert(type->abstract == false);
-    g_assert(size >= type->instance_size);
+    g_assert_cmpint(size, >=, type->instance_size);
 
     memset(obj, 0, type->instance_size);
     obj->class = type->class;
     object_ref(obj);
-    QTAILQ_INIT(&obj->properties);
+    obj->properties = g_hash_table_new_full(g_str_hash, g_str_equal,
+                                            NULL, object_property_free);
     object_init_with_type(obj, type);
     object_post_init_with_type(obj, type);
 }
@@ -359,29 +374,51 @@ static inline bool object_property_is_child(ObjectProperty *prop)
 
 static void object_property_del_all(Object *obj)
 {
-    while (!QTAILQ_EMPTY(&obj->properties)) {
-        ObjectProperty *prop = QTAILQ_FIRST(&obj->properties);
-
-        QTAILQ_REMOVE(&obj->properties, prop, node);
-
-        if (prop->release) {
-            prop->release(obj, prop->name, prop->opaque);
+    ObjectProperty *prop;
+    GHashTableIter iter;
+    gpointer key, value;
+    bool released;
+
+    do {
+        released = false;
+        g_hash_table_iter_init(&iter, obj->properties);
+        while (g_hash_table_iter_next(&iter, &key, &value)) {
+            prop = value;
+            if (prop->release) {
+                prop->release(obj, prop->name, prop->opaque);
+                prop->release = NULL;
+                released = true;
+                break;
+            }
+            g_hash_table_iter_remove(&iter);
         }
+    } while (released);
 
-        g_free(prop->name);
-        g_free(prop->type);
-        g_free(prop->description);
-        g_free(prop);
-    }
+    g_hash_table_unref(obj->properties);
 }
 
 static void object_property_del_child(Object *obj, Object *child, Error **errp)
 {
     ObjectProperty *prop;
+    GHashTableIter iter;
+    gpointer key, value;
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
+    g_hash_table_iter_init(&iter, obj->properties);
+    while (g_hash_table_iter_next(&iter, &key, &value)) {
+        prop = value;
+        if (object_property_is_child(prop) && prop->opaque == child) {
+            if (prop->release) {
+                prop->release(obj, prop->name, prop->opaque);
+                prop->release = NULL;
+            }
+            break;
+        }
+    }
+    g_hash_table_iter_init(&iter, obj->properties);
+    while (g_hash_table_iter_next(&iter, &key, &value)) {
+        prop = value;
         if (object_property_is_child(prop) && prop->opaque == child) {
-            object_property_del(obj, prop->name, errp);
+            g_hash_table_iter_remove(&iter);
             break;
         }
     }
@@ -413,7 +450,7 @@ static void object_finalize(void *data)
     object_property_del_all(obj);
     object_deinit(obj, ti);
 
-    g_assert(obj->ref == 0);
+    g_assert_cmpint(obj->ref, ==, 0);
     if (obj->free) {
         obj->free(obj);
     }
@@ -779,10 +816,12 @@ static int do_object_child_foreach(Object *obj,
                                    int (*fn)(Object *child, void *opaque),
                                    void *opaque, bool recurse)
 {
-    ObjectProperty *prop, *next;
+    GHashTableIter iter;
+    ObjectProperty *prop;
     int ret = 0;
 
-    QTAILQ_FOREACH_SAFE(prop, &obj->properties, node, next) {
+    g_hash_table_iter_init(&iter, obj->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         if (object_property_is_child(prop)) {
             Object *child = prop->opaque;
 
@@ -833,7 +872,7 @@ void object_ref(Object *obj)
     if (!obj) {
         return;
     }
-     atomic_inc(&obj->ref);
+    atomic_inc(&obj->ref);
 }
 
 void object_unref(Object *obj)
@@ -841,7 +880,7 @@ void object_unref(Object *obj)
     if (!obj) {
         return;
     }
-    g_assert(obj->ref > 0);
+    g_assert_cmpint(obj->ref, >, 0);
 
     /* parent always holds a reference to its children */
     if (atomic_fetch_dec(&obj->ref) == 1) {
@@ -879,13 +918,11 @@ object_property_add(Object *obj, const char *name, const char *type,
         return ret;
     }
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
-        if (strcmp(prop->name, name) == 0) {
-            error_setg(errp, "attempt to add duplicate property '%s'"
+    if (g_hash_table_lookup(obj->properties, name) != NULL) {
+        error_setg(errp, "attempt to add duplicate property '%s'"
                        " to object (type '%s')", name,
                        object_get_typename(obj));
-            return NULL;
-        }
+        return NULL;
     }
 
     prop = g_malloc0(sizeof(*prop));
@@ -898,7 +935,7 @@ object_property_add(Object *obj, const char *name, const char *type,
     prop->release = release;
     prop->opaque = opaque;
 
-    QTAILQ_INSERT_TAIL(&obj->properties, prop, node);
+    g_hash_table_insert(obj->properties, prop->name, prop);
     return prop;
 }
 
@@ -907,33 +944,52 @@ ObjectProperty *object_property_find(Object *obj, const char *name,
 {
     ObjectProperty *prop;
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
-        if (strcmp(prop->name, name) == 0) {
-            return prop;
-        }
+    prop = g_hash_table_lookup(obj->properties, name);
+    if (prop) {
+        return prop;
     }
 
     error_setg(errp, "Property '.%s' not found", name);
     return NULL;
 }
 
+ObjectPropertyIterator *object_property_iter_init(Object *obj)
+{
+    ObjectPropertyIterator *ret = g_new0(ObjectPropertyIterator, 1);
+    g_hash_table_iter_init(&ret->iter, obj->properties);
+    return ret;
+}
+
+void object_property_iter_free(ObjectPropertyIterator *iter)
+{
+    if (!iter) {
+        return;
+    }
+    g_free(iter);
+}
+
+ObjectProperty *object_property_iter_next(ObjectPropertyIterator *iter)
+{
+    gpointer key, val;
+    if (!g_hash_table_iter_next(&iter->iter, &key, &val)) {
+        return NULL;
+    }
+    return val;
+}
+
 void object_property_del(Object *obj, const char *name, Error **errp)
 {
-    ObjectProperty *prop = object_property_find(obj, name, errp);
-    if (prop == NULL) {
+    ObjectProperty *prop = g_hash_table_lookup(obj->properties, name);
+
+    if (!prop) {
+        error_setg(errp, "Property '.%s' not found", name);
         return;
     }
 
     if (prop->release) {
         prop->release(obj, name, prop->opaque);
     }
-
-    QTAILQ_REMOVE(&obj->properties, prop, node);
-
-    g_free(prop->name);
-    g_free(prop->type);
-    g_free(prop->description);
-    g_free(prop);
+    g_hash_table_remove(obj->properties, name);
 }
 
 void object_property_get(Object *obj, Visitor *v, const char *name,
@@ -1453,11 +1509,13 @@ void object_property_add_const_link(Object *obj, const char *name,
 gchar *object_get_canonical_path_component(Object *obj)
 {
     ObjectProperty *prop = NULL;
+    GHashTableIter iter;
 
     g_assert(obj);
     g_assert(obj->parent != NULL);
 
-    QTAILQ_FOREACH(prop, &obj->parent->properties, node) {
+    g_hash_table_iter_init(&iter, obj->parent->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         if (!object_property_is_child(prop)) {
             continue;
         }
@@ -1541,11 +1599,13 @@ static Object *object_resolve_partial_path(Object *parent,
                                               bool *ambiguous)
 {
     Object *obj;
+    GHashTableIter iter;
     ObjectProperty *prop;
 
     obj = object_resolve_abs_path(parent, parts, typename, 0);
 
-    QTAILQ_FOREACH(prop, &parent->properties, node) {
+    g_hash_table_iter_init(&iter, parent->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         Object *found;
 
         if (!object_property_is_child(prop)) {
diff --git a/tests/check-qom-proplist.c b/tests/check-qom-proplist.c
index 7400b1f..e674c0f 100644
--- a/tests/check-qom-proplist.c
+++ b/tests/check-qom-proplist.c
@@ -152,6 +152,148 @@ static const TypeInfo dummy_info = {
     .class_size = sizeof(DummyObjectClass),
 };
 
+
+/*
+ * The following 3 object classes are used to
+ * simulate the kind of relationships seen in
+ * qdev, which result in complex object
+ * property destruction ordering.
+ *
+ * DummyDev has a 'bus' child to a DummyBus
+ * DummyBus has a 'backend' child to a DummyBackend
+ * DummyDev has a 'backend' link to DummyBackend
+ *
+ * When DummyDev is finalized, it unparents the
+ * DummyBackend, which unparents the DummyDev
+ * which deletes the 'backend' link from DummyDev
+ * to DummyBackend. This illustrates that the
+ * object_property_del_all() method needs to
+ * cope with the list of properties being changed
+ * while it iterates over them.
+ */
+typedef struct DummyDev DummyDev;
+typedef struct DummyDevClass DummyDevClass;
+typedef struct DummyBus DummyBus;
+typedef struct DummyBusClass DummyBusClass;
+typedef struct DummyBackend DummyBackend;
+typedef struct DummyBackendClass DummyBackendClass;
+
+#define TYPE_DUMMY_DEV "qemu-dummy-dev"
+#define TYPE_DUMMY_BUS "qemu-dummy-bus"
+#define TYPE_DUMMY_BACKEND "qemu-dummy-backend"
+
+#define DUMMY_DEV(obj)                               \
+    OBJECT_CHECK(DummyDev, (obj), TYPE_DUMMY_DEV)
+#define DUMMY_BUS(obj)                               \
+    OBJECT_CHECK(DummyBus, (obj), TYPE_DUMMY_BUS)
+#define DUMMY_BACKEND(obj)                               \
+    OBJECT_CHECK(DummyBackend, (obj), TYPE_DUMMY_BACKEND)
+
+struct DummyDev {
+    Object parent_obj;
+
+    DummyBus *bus;
+};
+
+struct DummyDevClass {
+    ObjectClass parent_class;
+};
+
+struct DummyBus {
+    Object parent_obj;
+
+    DummyBackend *backend;
+};
+
+struct DummyBusClass {
+    ObjectClass parent_class;
+};
+
+struct DummyBackend {
+    Object parent_obj;
+};
+
+struct DummyBackendClass {
+    ObjectClass parent_class;
+};
+
+
+static void dummy_dev_init(Object *obj)
+{
+    DummyDev *dev = DUMMY_DEV(obj);
+    DummyBus *bus = DUMMY_BUS(object_new(TYPE_DUMMY_BUS));
+    DummyBackend *backend = DUMMY_BACKEND(object_new(TYPE_DUMMY_BACKEND));
+
+    object_property_add_child(obj, "bus", OBJECT(bus), NULL);
+    dev->bus = bus;
+    object_property_add_child(OBJECT(bus), "backend", OBJECT(backend), NULL);
+    bus->backend = backend;
+
+    object_property_add_link(obj, "backend", TYPE_DUMMY_BACKEND,
+                             (Object **)&bus->backend, NULL, 0, NULL);
+}
+
+static void dummy_dev_unparent(Object *obj)
+{
+    DummyDev *dev = DUMMY_DEV(obj);
+    object_unparent(OBJECT(dev->bus));
+}
+
+static void dummy_dev_class_init(ObjectClass *klass, void *opaque)
+{
+    klass->unparent = dummy_dev_unparent;
+}
+
+
+static void dummy_bus_init(Object *obj)
+{
+}
+
+static void dummy_bus_unparent(Object *obj)
+{
+    DummyBus *bus = DUMMY_BUS(obj);
+    object_property_del(obj->parent, "backend", NULL);
+    object_unparent(OBJECT(bus->backend));
+}
+
+static void dummy_bus_class_init(ObjectClass *klass, void *opaque)
+{
+    klass->unparent = dummy_bus_unparent;
+}
+
+static void dummy_backend_init(Object *obj)
+{
+}
+
+
+static const TypeInfo dummy_dev_info = {
+    .name          = TYPE_DUMMY_DEV,
+    .parent        = TYPE_OBJECT,
+    .instance_size = sizeof(DummyDev),
+    .instance_init = dummy_dev_init,
+    .class_size = sizeof(DummyDevClass),
+    .class_init = dummy_dev_class_init,
+};
+
+static const TypeInfo dummy_bus_info = {
+    .name          = TYPE_DUMMY_BUS,
+    .parent        = TYPE_OBJECT,
+    .instance_size = sizeof(DummyBus),
+    .instance_init = dummy_bus_init,
+    .class_size = sizeof(DummyBusClass),
+    .class_init = dummy_bus_class_init,
+};
+
+static const TypeInfo dummy_backend_info = {
+    .name          = TYPE_DUMMY_BACKEND,
+    .parent        = TYPE_OBJECT,
+    .instance_size = sizeof(DummyBackend),
+    .instance_init = dummy_backend_init,
+    .class_size = sizeof(DummyBackendClass),
+};
+
+
+
 static void test_dummy_createv(void)
 {
     Error *err = NULL;
@@ -283,20 +425,83 @@ static void test_dummy_getenum(void)
                                    &err);
     g_assert(err != NULL);
     error_free(err);
+
+    object_unparent(OBJECT(dobj));
 }
 
 
+static void test_dummy_iterator(void)
+{
+    Object *parent = object_get_objects_root();
+    DummyObject *dobj = DUMMY_OBJECT(
+        object_new_with_props(TYPE_DUMMY,
+                              parent,
+                              "dummy0",
+                              &error_abort,
+                              "bv", "yes",
+                              "sv", "Hiss hiss hiss",
+                              "av", "platypus",
+                              NULL));
+
+    ObjectProperty *prop;
+    ObjectPropertyIterator *iter;
+    bool seenbv = false, seensv = false, seenav = false, seentype;
+
+    iter = object_property_iter_init(OBJECT(dobj));
+    while ((prop = object_property_iter_next(iter))) {
+        if (g_str_equal(prop->name, "bv")) {
+            seenbv = true;
+        } else if (g_str_equal(prop->name, "sv")) {
+            seensv = true;
+        } else if (g_str_equal(prop->name, "av")) {
+            seenav = true;
+        } else if (g_str_equal(prop->name, "type")) {
+            /* This prop comes from the base Object class */
+            seentype = true;
+        } else {
+            g_printerr("Found prop '%s'\n", prop->name);
+            g_assert_not_reached();
+        }
+    }
+    object_property_iter_free(iter);
+    g_assert(seenbv);
+    g_assert(seenav);
+    g_assert(seensv);
+    g_assert(seentype);
+
+    object_unparent(OBJECT(dobj));
+}
+
+
+static void test_dummy_delchild(void)
+{
+    Object *parent = object_get_objects_root();
+    DummyDev *dev = DUMMY_DEV(
+        object_new_with_props(TYPE_DUMMY_DEV,
+                              parent,
+                              "dev0",
+                              &error_abort,
+                              NULL));
+
+    object_unparent(OBJECT(dev));
+}
+
 int main(int argc, char **argv)
 {
     g_test_init(&argc, &argv, NULL);
 
     module_call_init(MODULE_INIT_QOM);
     type_register_static(&dummy_info);
+    type_register_static(&dummy_dev_info);
+    type_register_static(&dummy_bus_info);
+    type_register_static(&dummy_backend_info);
 
     g_test_add_func("/qom/proplist/createlist", test_dummy_createlist);
     g_test_add_func("/qom/proplist/createv", test_dummy_createv);
     g_test_add_func("/qom/proplist/badenum", test_dummy_badenum);
     g_test_add_func("/qom/proplist/getenum", test_dummy_getenum);
+    g_test_add_func("/qom/proplist/iterator", test_dummy_iterator);
+    g_test_add_func("/qom/proplist/delchild", test_dummy_delchild);
 
     return g_test_run();
 }
diff --git a/vl.c b/vl.c
index f9c661a..525929b 100644
--- a/vl.c
+++ b/vl.c
@@ -1536,12 +1536,14 @@ MachineInfoList *qmp_query_machines(Error **errp)
 static int machine_help_func(QemuOpts *opts, MachineState *machine)
 {
     ObjectProperty *prop;
+    ObjectPropertyIterator *iter;
 
     if (!qemu_opt_has_help_opt(opts)) {
         return 0;
     }
 
-    QTAILQ_FOREACH(prop, &OBJECT(machine)->properties, node) {
+    iter = object_property_iter_init(OBJECT(machine));
+    while ((prop = object_property_iter_next(iter))) {
         if (!prop->set) {
             continue;
         }
@@ -1554,6 +1556,7 @@ static int machine_help_func(QemuOpts *opts, MachineState *machine)
             error_printf("\n");
         }
     }
+    object_property_iter_free(iter);
 
     return 1;
 }