Merge remote-tracking branch 'bonzini/qdev-props-for-anthony' into staging

* bonzini/qdev-props-for-anthony: (25 commits)
  qdev: remove unused fields from PropertyInfo
  qdev: initialize properties via QOM
  qdev: inline qdev_prop_set into qdev_prop_set_ptr
  qdev: access properties via QOM
  qdev: fix off-by-one
  qdev: let QOM free properties
  qdev: remove parse/print methods for pointer properties
  qdev: make the non-legacy pci address property accept an integer
  qdev: remove parse/print methods for mac properties
  qdev: remove print/parse methods from LostTickPolicy properties
  qdev: remove parse method for string properties
  qdev: allow reusing get/set for legacy property
  qdev: remove direct calls to print/parse
  qom: add property get/set wrappers for links
  qom: fix canonical paths vs. interfaces
  qom: use object_resolve_path_type for links
  qom: add object_resolve_path_type
  qom: fix off-by-one
  qom: add property get/set wrappers for C types
  qom: add QObject-based property get/set wrappers
  ...

hw/qdev-addr.c

@@ -61,8 +61,6 @@ static void set_taddr(Object *obj, Visitor *v, void *opaque,
 
 PropertyInfo qdev_prop_taddr = {
     .name  = "taddr",
-    .type  = PROP_TYPE_TADDR,
-    .size  = sizeof(target_phys_addr_t),
     .parse = parse_taddr,
     .print = print_taddr,
     .get   = get_taddr,
@@ -71,5 +69,8 @@ PropertyInfo qdev_prop_taddr = {
 
 void qdev_prop_set_taddr(DeviceState *dev, const char *name, target_phys_addr_t value)
 {
-    qdev_prop_set(dev, name, &value, PROP_TYPE_TADDR);
+    Error *errp = NULL;
+    object_property_set_int(OBJECT(dev), value, name, &errp);
+    assert(!errp);
+
 }

hw/qdev-monitor.c

@@ -485,22 +485,26 @@ static void qbus_print(Monitor *mon, BusState *bus, int indent);
 static void qdev_print_props(Monitor *mon, DeviceState *dev, Property *props,
                              const char *prefix, int indent)
 {
-    char buf[64];
-
     if (!props)
         return;
-    while (props->name) {
-        /*
-         * TODO Properties without a print method are just for dirty
-         * hacks.  qdev_prop_ptr is the only such PropertyInfo.  It's
-         * marked for removal.  The test props->info->print should be
-         * removed along with it.
-         */
-        if (props->info->print) {
-            props->info->print(dev, props, buf, sizeof(buf));
-            qdev_printf("%s-prop: %s = %s\n", prefix, props->name, buf);
+    for (; props->name; props++) {
+        Error *err = NULL;
+        char *value;
+        char *legacy_name = g_strdup_printf("legacy-%s", props->name);
+        if (object_property_get_type(OBJECT(dev), legacy_name, NULL)) {
+            value = object_property_get_str(OBJECT(dev), legacy_name, &err);
+        } else {
+            value = object_property_get_str(OBJECT(dev), props->name, &err);
+        }
+        g_free(legacy_name);
+
+        if (err) {
+            error_free(err);
+            continue;
         }
-        props++;
+        qdev_printf("%s-prop: %s = %s\n", prefix, props->name,
+                    value && *value ? value : "<null>");
+        g_free(value);
     }
 }
 

hw/qdev.c

@@ -86,11 +86,11 @@ void qdev_set_parent_bus(DeviceState *dev, BusState *bus)
     dev->parent_bus = bus;
     QTAILQ_INSERT_HEAD(&bus->children, dev, sibling);
 
-    qdev_prop_set_defaults(dev, dev->parent_bus->info->props);
     for (prop = qdev_get_bus_info(dev)->props; prop && prop->name; prop++) {
         qdev_property_add_legacy(dev, prop, NULL);
         qdev_property_add_static(dev, prop, NULL);
     }
+    qdev_prop_set_defaults(dev, dev->parent_bus->info->props);
 }
 
 /* Create a new device.  This only initializes the device state structure
@@ -550,21 +550,24 @@ static void qdev_set_legacy_property(Object *obj, Visitor *v, void *opaque,
  * Do not use this is new code!  Properties added through this interface will
  * be given names and types in the "legacy" namespace.
  *
- * Legacy properties are always processed as strings.  The format of the string
- * depends on the property type.
+ * Legacy properties are string versions of other OOM properties.  The format
+ * of the string depends on the property type.
  */
 void qdev_property_add_legacy(DeviceState *dev, Property *prop,
                               Error **errp)
 {
     gchar *name, *type;
 
+    if (!prop->info->print && !prop->info->parse) {
+        return;
+    }
     name = g_strdup_printf("legacy-%s", prop->name);
     type = g_strdup_printf("legacy<%s>",
                            prop->info->legacy_name ?: prop->info->name);
 
     object_property_add(OBJECT(dev), name, type,
-                        prop->info->print ? qdev_get_legacy_property : NULL,
-                        prop->info->parse ? qdev_set_legacy_property : NULL,
+                        prop->info->print ? qdev_get_legacy_property : prop->info->get,
+                        prop->info->parse ? qdev_set_legacy_property : prop->info->set,
                         NULL,
                         prop, errp);
 
@@ -581,9 +584,18 @@ void qdev_property_add_legacy(DeviceState *dev, Property *prop,
 void qdev_property_add_static(DeviceState *dev, Property *prop,
                               Error **errp)
 {
+    /*
+     * TODO qdev_prop_ptr does not have getters or setters.  It must
+     * go now that it can be replaced with links.  The test should be
+     * removed along with it: all static properties are read/write.
+     */
+    if (!prop->info->get && !prop->info->set) {
+        return;
+    }
+
     object_property_add(OBJECT(dev), prop->name, prop->info->name,
                         prop->info->get, prop->info->set,
-                        NULL,
+                        prop->info->release,
                         prop, errp);
 }
 
@@ -600,13 +612,13 @@ static void device_initfn(Object *obj)
     dev->instance_id_alias = -1;
     dev->state = DEV_STATE_CREATED;
 
-    qdev_prop_set_defaults(dev, qdev_get_props(dev));
     for (prop = qdev_get_props(dev); prop && prop->name; prop++) {
         qdev_property_add_legacy(dev, prop, NULL);
         qdev_property_add_static(dev, prop, NULL);
     }
 
     object_property_add_str(OBJECT(dev), "type", qdev_get_type, NULL, NULL);
+    qdev_prop_set_defaults(dev, qdev_get_props(dev));
 }
 
 /* Unlink device from bus and free the structure.  */
@@ -614,7 +626,6 @@ static void device_finalize(Object *obj)
 {
     DeviceState *dev = DEVICE(obj);
     BusState *bus;
-    Property *prop;
     DeviceClass *dc = DEVICE_GET_CLASS(dev);
 
     if (dev->state == DEV_STATE_INITIALIZED) {
@@ -633,11 +644,6 @@ static void device_finalize(Object *obj)
         }
     }
     QTAILQ_REMOVE(&dev->parent_bus->children, dev, sibling);
-    for (prop = qdev_get_props(dev); prop && prop->name; prop++) {
-        if (prop->info->free) {
-            prop->info->free(dev, prop);
-        }
-    }
 }
 
 void device_reset(DeviceState *dev)

hw/qdev.h

@@ -112,41 +112,22 @@ struct Property {
     const char   *name;
     PropertyInfo *info;
     int          offset;
-    int          bitnr;
-    void         *defval;
-};
-
-enum PropertyType {
-    PROP_TYPE_UNSPEC = 0,
-    PROP_TYPE_UINT8,
-    PROP_TYPE_UINT16,
-    PROP_TYPE_UINT32,
-    PROP_TYPE_INT32,
-    PROP_TYPE_UINT64,
-    PROP_TYPE_TADDR,
-    PROP_TYPE_MACADDR,
-    PROP_TYPE_LOSTTICKPOLICY,
-    PROP_TYPE_DRIVE,
-    PROP_TYPE_CHR,
-    PROP_TYPE_STRING,
-    PROP_TYPE_NETDEV,
-    PROP_TYPE_VLAN,
-    PROP_TYPE_PTR,
-    PROP_TYPE_BIT,
+    uint8_t      bitnr;
+    uint8_t      qtype;
+    int64_t      defval;
 };
 
 struct PropertyInfo {
     const char *name;
     const char *legacy_name;
-    size_t size;
-    enum PropertyType type;
+    const char **enum_table;
     int64_t min;
     int64_t max;
     int (*parse)(DeviceState *dev, Property *prop, const char *str);
     int (*print)(DeviceState *dev, Property *prop, char *dest, size_t len);
-    void (*free)(DeviceState *dev, Property *prop);
     ObjectPropertyAccessor *get;
     ObjectPropertyAccessor *set;
+    ObjectPropertyRelease *release;
 };
 
 typedef struct GlobalProperty {
@@ -254,7 +235,8 @@ extern PropertyInfo qdev_prop_pci_devfn;
         .info      = &(_prop),                                          \
         .offset    = offsetof(_state, _field)                           \
             + type_check(_type,typeof_field(_state, _field)),           \
-        .defval    = (_type[]) { _defval },                             \
+        .qtype     = QTYPE_QINT,                                        \
+        .defval    = (_type)_defval,                                    \
         }
 #define DEFINE_PROP_BIT(_name, _state, _field, _bit, _defval) {  \
         .name      = (_name),                                    \
@@ -262,7 +244,8 @@ extern PropertyInfo qdev_prop_pci_devfn;
         .bitnr    = (_bit),                                      \
         .offset    = offsetof(_state, _field)                    \
             + type_check(uint32_t,typeof_field(_state, _field)), \
-        .defval    = (bool[]) { (_defval) },                     \
+        .qtype     = QTYPE_QBOOL,                                \
+        .defval    = (bool)_defval,                              \
         }
 
 #define DEFINE_PROP_UINT8(_n, _s, _f, _d)                       \
@@ -309,7 +292,6 @@ extern PropertyInfo qdev_prop_pci_devfn;
 void *qdev_get_prop_ptr(DeviceState *dev, Property *prop);
 int qdev_prop_exists(DeviceState *dev, const char *name);
 int qdev_prop_parse(DeviceState *dev, const char *name, const char *value);
-void qdev_prop_set(DeviceState *dev, const char *name, void *src, enum PropertyType type);
 void qdev_prop_set_bit(DeviceState *dev, const char *name, bool value);
 void qdev_prop_set_uint8(DeviceState *dev, const char *name, uint8_t value);
 void qdev_prop_set_uint16(DeviceState *dev, const char *name, uint16_t value);
@@ -323,8 +305,7 @@ void qdev_prop_set_vlan(DeviceState *dev, const char *name, VLANState *value);
 int qdev_prop_set_drive(DeviceState *dev, const char *name, BlockDriverState *value) QEMU_WARN_UNUSED_RESULT;
 void qdev_prop_set_drive_nofail(DeviceState *dev, const char *name, BlockDriverState *value);
 void qdev_prop_set_macaddr(DeviceState *dev, const char *name, uint8_t *value);
-void qdev_prop_set_losttickpolicy(DeviceState *dev, const char *name,
-                                  LostTickPolicy *value);
+void qdev_prop_set_enum(DeviceState *dev, const char *name, int value);
 /* FIXME: Remove opaque pointer properties.  */
 void qdev_prop_set_ptr(DeviceState *dev, const char *name, void *value);
 void qdev_prop_set_defaults(DeviceState *dev, Property *props);

include/qemu/object.h

@@ -55,6 +55,9 @@ typedef struct InterfaceInfo InterfaceInfo;
  *
  * #define TYPE_MY_DEVICE "my-device"
  *
+ * // No new virtual functions: we can reuse the typedef for the
+ * // superclass.
+ * typedef DeviceClass MyDeviceClass;
  * typedef struct MyDevice
  * {
  *     DeviceState parent;
@@ -88,8 +91,21 @@ typedef struct InterfaceInfo InterfaceInfo;
  *
  * Using object_new(), a new #Object derivative will be instantiated.  You can
  * cast an #Object to a subclass (or base-class) type using
- * object_dynamic_cast().  You typically want to define a macro wrapper around
- * object_dynamic_cast_assert() to make it easier to convert to a specific type.
+ * object_dynamic_cast().  You typically want to define macro wrappers around
+ * OBJECT_CHECK() and OBJECT_CLASS_CHECK() to make it easier to convert to a
+ * specific type:
+ *
+ * <example>
+ *   <title>Typecasting macros</title>
+ *   <programlisting>
+ *    #define MY_DEVICE_GET_CLASS(obj) \
+ *       OBJECT_GET_CLASS(MyDeviceClass, obj, TYPE_MY_DEVICE)
+ *    #define MY_DEVICE_CLASS(klass) \
+ *       OBJECT_CLASS_CHECK(MyDeviceClass, klass, TYPE_MY_DEVICE)
+ *    #define MY_DEVICE(obj) \
+ *       OBJECT_CHECK(MyDevice, obj, TYPE_MY_DEVICE)
+ *   </programlisting>
+ * </example>
  *
  * # Class Initialization #
  *
@@ -108,7 +124,61 @@ typedef struct InterfaceInfo InterfaceInfo;
  *
  * Once all of the parent classes have been initialized, #TypeInfo::class_init
  * is called to let the class being instantiated provide default initialize for
- * it's virtual functions.
+ * it's virtual functions.  Here is how the above example might be modified
+ * to introduce an overridden virtual function:
+ *
+ * <example>
+ *   <title>Overriding a virtual function</title>
+ *   <programlisting>
+ * #include "qdev.h"
+ *
+ * void my_device_class_init(ObjectClass *klass, void *class_data)
+ * {
+ *     DeviceClass *dc = DEVICE_CLASS(klass);
+ *     dc->reset = my_device_reset;
+ * }
+ *
+ * static TypeInfo my_device_info = {
+ *     .name = TYPE_MY_DEVICE,
+ *     .parent = TYPE_DEVICE,
+ *     .instance_size = sizeof(MyDevice),
+ *     .class_init = my_device_class_init,
+ * };
+ *   </programlisting>
+ * </example>
+ *
+ * Introducing new virtual functions requires a class to define its own
+ * struct and to add a .class_size member to the TypeInfo.  Each function
+ * will also have a wrapper to call it easily:
+ *
+ * <example>
+ *   <title>Defining an abstract class</title>
+ *   <programlisting>
+ * #include "qdev.h"
+ *
+ * typedef struct MyDeviceClass
+ * {
+ *     DeviceClass parent;
+ *
+ *     void (*frobnicate) (MyDevice *obj);
+ * } MyDeviceClass;
+ *
+ * static TypeInfo my_device_info = {
+ *     .name = TYPE_MY_DEVICE,
+ *     .parent = TYPE_DEVICE,
+ *     .instance_size = sizeof(MyDevice),
+ *     .abstract = true, // or set a default in my_device_class_init
+ *     .class_size = sizeof(MyDeviceClass),
+ * };
+ *
+ * void my_device_frobnicate(MyDevice *obj)
+ * {
+ *     MyDeviceClass *klass = MY_DEVICE_GET_CLASS(obj);
+ *
+ *     klass->frobnicate(obj);
+ * }
+ *   </programlisting>
+ * </example>
  *
  * # Interfaces #
  *
@@ -258,6 +328,16 @@ struct TypeInfo
 #define OBJECT(obj) \
     ((Object *)(obj))
 
+/**
+ * OBJECT_CLASS:
+ * @class: A derivative of #ObjectClas.
+ *
+ * Converts a class to an #ObjectClass.  Since all objects are #Objects,
+ * this function will always succeed.
+ */
+#define OBJECT_CLASS(class) \
+    ((ObjectClass *)(class))
+
 /**
  * OBJECT_CHECK:
  * @type: The C type to use for the return value.
@@ -272,7 +352,7 @@ struct TypeInfo
  * generated.
  */
 #define OBJECT_CHECK(type, obj, name) \
-    ((type *)object_dynamic_cast_assert((Object *)(obj), (name)))
+    ((type *)object_dynamic_cast_assert(OBJECT(obj), (name)))
 
 /**
  * OBJECT_CLASS_CHECK:
@@ -280,11 +360,12 @@ struct TypeInfo
  * @obj: A derivative of @type to cast.
  * @name: the QOM typename of @class.
  *
- * A type safe version of @object_check_class.  This macro is typically wrapped
- * by each type to perform type safe casts of a class to a specific class type.
+ * A type safe version of @object_class_dynamic_cast_assert.  This macro is
+ * typically wrapped by each type to perform type safe casts of a class to a
+ * specific class type.
  */
 #define OBJECT_CLASS_CHECK(class, obj, name) \
-    ((class *)object_class_dynamic_cast_assert((ObjectClass *)(obj), (name)))
+    ((class *)object_class_dynamic_cast_assert(OBJECT_CLASS(obj), (name)))
 
 /**
  * OBJECT_GET_CLASS:
@@ -299,9 +380,6 @@ struct TypeInfo
 #define OBJECT_GET_CLASS(class, obj, name) \
     OBJECT_CLASS_CHECK(class, object_get_class(OBJECT(obj)), name)
 
-#define OBJECT_CLASS(class) \
-    ((ObjectClass *)(class))
-
 /**
  * InterfaceClass:
  * @parent_class: the base class
@@ -543,6 +621,100 @@ void object_unparent(Object *obj);
 void object_property_get(Object *obj, struct Visitor *v, const char *name,
                          struct Error **errp);
 
+/**
+ * object_property_set_str:
+ * @value: the value to be written to the property
+ * @name: the name of the property
+ * @errp: returns an error if this function fails
+ *
+ * Writes a string value to a property.
+ */
+void object_property_set_str(Object *obj, const char *value,
+                             const char *name, struct Error **errp);
+
+/**
+ * object_property_get_str:
+ * @obj: the object
+ * @name: the name of the property
+ * @errp: returns an error if this function fails
+ *
+ * Returns: the value of the property, converted to a C string, or NULL if
+ * an error occurs (including when the property value is not a string).
+ * The caller should free the string.
+ */
+char *object_property_get_str(Object *obj, const char *name,
+                              struct Error **errp);
+
+/**
+ * object_property_set_link:
+ * @value: the value to be written to the property
+ * @name: the name of the property
+ * @errp: returns an error if this function fails
+ *
+ * Writes an object's canonical path to a property.
+ */
+void object_property_set_link(Object *obj, Object *value,
+                              const char *name, struct Error **errp);
+
+/**
+ * object_property_get_link:
+ * @obj: the object
+ * @name: the name of the property
+ * @errp: returns an error if this function fails
+ *
+ * Returns: the value of the property, resolved from a path to an Object,
+ * or NULL if an error occurs (including when the property value is not a
+ * string or not a valid object path).
+ */
+Object *object_property_get_link(Object *obj, const char *name,
+                                 struct Error **errp);
+
+/**
+ * object_property_set_bool:
+ * @value: the value to be written to the property
+ * @name: the name of the property
+ * @errp: returns an error if this function fails
+ *
+ * Writes a bool value to a property.
+ */
+void object_property_set_bool(Object *obj, bool value,
+                              const char *name, struct Error **errp);
+
+/**
+ * object_property_get_bool:
+ * @obj: the object
+ * @name: the name of the property
+ * @errp: returns an error if this function fails
+ *
+ * Returns: the value of the property, converted to a boolean, or NULL if
+ * an error occurs (including when the property value is not a bool).
+ */
+bool object_property_get_bool(Object *obj, const char *name,
+                              struct Error **errp);
+
+/**
+ * object_property_set_int:
+ * @value: the value to be written to the property
+ * @name: the name of the property
+ * @errp: returns an error if this function fails
+ *
+ * Writes an integer value to a property.
+ */
+void object_property_set_int(Object *obj, int64_t value,
+                             const char *name, struct Error **errp);
+
+/**
+ * object_property_get_int:
+ * @obj: the object
+ * @name: the name of the property
+ * @errp: returns an error if this function fails
+ *
+ * Returns: the value of the property, converted to an integer, or NULL if
+ * an error occurs (including when the property value is not an integer).
+ */
+int64_t object_property_get_int(Object *obj, const char *name,
+                                struct Error **errp);
+
 /**
  * object_property_set:
  * @obj: the object
@@ -601,13 +773,34 @@ gchar *object_get_canonical_path(Object *obj);
  * specifying objects easy.  At each level of the composition tree, the partial
  * path is matched as an absolute path.  The first match is not returned.  At
  * least two matches are searched for.  A successful result is only returned if
- * only one match is founded.  If more than one match is found, a flag is
- * return to indicate that the match was ambiguous.
+ * only one match is found.  If more than one match is found, a flag is
+ * returned to indicate that the match was ambiguous.
  *
  * Returns: The matched object or NULL on path lookup failure.
  */
 Object *object_resolve_path(const char *path, bool *ambiguous);
 
+/**
+ * object_resolve_path_type:
+ * @path: the path to resolve
+ * @typename: the type to look for.
+ * @ambiguous: returns true if the path resolution failed because of an
+ *   ambiguous match
+ *
+ * This is similar to object_resolve_path.  However, when looking for a
+ * partial path only matches that implement the given type are considered.
+ * This restricts the search and avoids spuriously flagging matches as
+ * ambiguous.
+ *
+ * For both partial and absolute paths, the return value goes through
+ * a dynamic cast to @typename.  This is important if either the link,
+ * or the typename itself are of interface types.
+ *
+ * Returns: The matched object or NULL on path lookup failure.
+ */
+Object *object_resolve_path_type(const char *path, const char *typename,
+                                 bool *ambiguous);
+
 /**
  * object_property_add_child:
  * @obj: the object to add a property to

include/qemu/qom-qobject.h

+/*
+ * QEMU Object Model - QObject wrappers
+ *
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#ifndef QEMU_QOM_QOBJECT_H
+#define QEMU_QOM_QOBJECT_H
+
+#include "qemu/object.h"
+
+/*
+ * object_property_get_qobject:
+ * @obj: the object
+ * @name: the name of the property
+ * @errp: returns an error if this function fails
+ *
+ * Returns: the value of the property, converted to QObject, or NULL if
+ * an error occurs.
+ */
+struct QObject *object_property_get_qobject(Object *obj, const char *name,
+                                            struct Error **errp);
+
+/**
+ * object_property_set_qobject:
+ * @obj: the object
+ * @ret: The value that will be written to the property.
+ * @name: the name of the property
+ * @errp: returns an error if this function fails
+ *
+ * Writes a property to a object.
+ */
+void object_property_set_qobject(Object *obj, struct QObject *qobj,
+                                 const char *name, struct Error **errp);
+
+#endif

qemu-common.h

@@ -255,6 +255,7 @@ typedef enum LostTickPolicy {
     LOST_TICK_DELAY,
     LOST_TICK_MERGE,
     LOST_TICK_SLEW,
+    LOST_TICK_MAX
 } LostTickPolicy;
 
 void tcg_exec_init(unsigned long tb_size);

qerror.c

@@ -47,6 +47,10 @@ static const QErrorStringTable qerror_table[] = {
         .error_fmt = QERR_ADD_CLIENT_FAILED,
         .desc      = "Could not add client",
     },
+    {
+        .error_fmt = QERR_AMBIGUOUS_PATH,
+        .desc      = "Path '%(path)' does not uniquely identify a %(object)"
+    },
     {
         .error_fmt = QERR_BAD_BUS_FOR_DEVICE,
         .desc      = "Device '%(device)' can't go on a %(bad_bus_type) bus",

qerror.h

@@ -54,6 +54,9 @@ QError *qobject_to_qerror(const QObject *obj);
 #define QERR_ADD_CLIENT_FAILED \
     "{ 'class': 'AddClientFailed', 'data': {} }"
 
+#define QERR_AMBIGUOUS_PATH \
+    "{ 'class': 'AmbiguousPath', 'data': { 'path': %s } }"
+
 #define QERR_BAD_BUS_FOR_DEVICE \
     "{ 'class': 'BadBusForDevice', 'data': { 'device': %s, 'bad_bus_type': %s } }"
 

qmp.c

@@ -21,9 +21,8 @@
 #include "kvm.h"
 #include "arch_init.h"
 #include "hw/qdev.h"
-#include "qapi/qmp-input-visitor.h"
-#include "qapi/qmp-output-visitor.h"
 #include "blockdev.h"
+#include "qemu/qom-qobject.h"
 
 NameInfo *qmp_query_name(Error **errp)
 {
@@ -198,7 +197,6 @@ int qmp_qom_set(Monitor *mon, const QDict *qdict, QObject **ret)
     const char *property = qdict_get_str(qdict, "property");
     QObject *value = qdict_get(qdict, "value");
     Error *local_err = NULL;
-    QmpInputVisitor *mi;
     Object *obj;
 
     obj = object_resolve_path(path, NULL);
@@ -207,10 +205,7 @@ int qmp_qom_set(Monitor *mon, const QDict *qdict, QObject **ret)
         goto out;
     }
 
-    mi = qmp_input_visitor_new(value);
-    object_property_set(obj, qmp_input_get_visitor(mi), property, &local_err);
-
-    qmp_input_visitor_cleanup(mi);
+    object_property_set_qobject(obj, value, property, &local_err);
 
 out:
     if (local_err) {
@@ -227,7 +222,6 @@ int qmp_qom_get(Monitor *mon, const QDict *qdict, QObject **ret)
     const char *path = qdict_get_str(qdict, "path");
     const char *property = qdict_get_str(qdict, "property");
     Error *local_err = NULL;
-    QmpOutputVisitor *mo;
     Object *obj;
 
     obj = object_resolve_path(path, NULL);
@@ -236,13 +230,7 @@ int qmp_qom_get(Monitor *mon, const QDict *qdict, QObject **ret)
         goto out;
     }
 
-    mo = qmp_output_visitor_new();
-    object_property_get(obj, qmp_output_get_visitor(mo), property, &local_err);
-    if (!local_err) {
-        *ret = qmp_output_get_qobject(mo);
-    }
-
-    qmp_output_visitor_cleanup(mo);
+    *ret = object_property_get_qobject(obj, property, &local_err);
 
 out:
     if (local_err) {

qom/Makefile

-qom-y = object.o container.o
+qom-y = object.o container.o qom-qobject.o

qom/object.c

@@ -13,8 +13,14 @@
 #include "qemu/object.h"
 #include "qemu-common.h"
 #include "qapi/qapi-visit-core.h"
-#include "hw/qdev.h"
-// FIXME remove above
+
+/* TODO: replace QObject with a simpler visitor to avoid a dependency
+ * of the QOM core on QObject?  */
+#include "qemu/qom-qobject.h"
+#include "qobject.h"
+#include "qbool.h"
+#include "qint.h"
+#include "qstring.h"
 
 #define MAX_INTERFACES 32
 
@@ -63,6 +69,8 @@ typedef struct Interface
 
 #define INTERFACE(obj) OBJECT_CHECK(Interface, obj, TYPE_INTERFACE)
 
+static Type type_interface;
+
 static GHashTable *type_table_get(void)
 {
     static GHashTable *type_table;
@@ -368,11 +376,9 @@ void object_delete(Object *obj)
     g_free(obj);
 }
 
-static bool object_is_type(Object *obj, const char *typename)
+static bool type_is_ancestor(TypeImpl *type, TypeImpl *target_type)
 {
-    TypeImpl *target_type = type_get_by_name(typename);
-    TypeImpl *type = obj->class->type;
-    GSList *i;
+    assert(target_type);
 
     /* Check if typename is a direct ancestor of type */
     while (type) {
@@ -383,24 +389,45 @@ static bool object_is_type(Object *obj, const char *typename)
         type = type_get_parent(type);
     }
 
-    /* Check if obj has an interface of typename */
-    for (i = obj->interfaces; i; i = i->next) {
-        Interface *iface = i->data;
-
-        if (object_is_type(OBJECT(iface), typename)) {
-            return true;
-        }
-    }
-
     return false;
 }
 
+static bool object_is_type(Object *obj, TypeImpl *target_type)
+{
+    return !target_type || type_is_ancestor(obj->class->type, target_type);
+}
+
 Object *object_dynamic_cast(Object *obj, const char *typename)
 {
+    TypeImpl *target_type = type_get_by_name(typename);
     GSList *i;
 
-    /* Check if typename is a direct ancestor */
-    if (object_is_type(obj, typename)) {
+    /* Check if typename is a direct ancestor.  Special-case TYPE_OBJECT,
+     * we want to go back from interfaces to the parent.
+    */
+    if (target_type && object_is_type(obj, target_type)) {
+        return obj;
+    }
+
+    /* Check if obj is an interface and its containing object is a direct
+     * ancestor of typename.  In principle we could do this test at the very
+     * beginning of object_dynamic_cast, avoiding a second call to
+     * object_is_type.  However, casting between interfaces is relatively
+     * rare, and object_is_type(obj, type_interface) would fail almost always.
+     *
+     * Perhaps we could add a magic value to the object header for increased
+     * (run-time) type safety and to speed up tests like this one.  If we ever
+     * do that we can revisit the order here.
+     */
+    if (object_is_type(obj, type_interface)) {
+        assert(!obj->interfaces);
+        obj = INTERFACE(obj)->obj;
+        if (object_is_type(obj, target_type)) {
+            return obj;
+        }
+    }
+
+    if (!target_type) {
         return obj;
     }
 
@@ -408,21 +435,11 @@ Object *object_dynamic_cast(Object *obj, const char *typename)
     for (i = obj->interfaces; i; i = i->next) {
         Interface *iface = i->data;
 
-        if (object_is_type(OBJECT(iface), typename)) {
+        if (object_is_type(OBJECT(iface), target_type)) {
             return OBJECT(iface);
         }
     }
 
-    /* Check if obj is an interface and its containing object is a direct
-     * ancestor of typename */
-    if (object_is_type(obj, TYPE_INTERFACE)) {
-        Interface *iface = INTERFACE(obj);
-
-        if (object_is_type(iface->obj, typename)) {
-            return iface->obj;
-        }
-    }
-
     return NULL;
 }
 
@@ -435,7 +452,7 @@ static void register_interface(void)
         .abstract = true,
     };
 
-    type_register_static(&interface_info);
+    type_interface = type_register_static(&interface_info);
 }
 
 device_init(register_interface);
@@ -648,6 +665,123 @@ void object_property_set(Object *obj, Visitor *v, const char *name,
     }
 }
 
+void object_property_set_str(Object *obj, const char *value,
+                             const char *name, Error **errp)
+{
+    QString *qstr = qstring_from_str(value);
+    object_property_set_qobject(obj, QOBJECT(qstr), name, errp);
+
+    QDECREF(qstr);
+}
+
+char *object_property_get_str(Object *obj, const char *name,
+                              Error **errp)
+{
+    QObject *ret = object_property_get_qobject(obj, name, errp);
+    QString *qstring;
+    char *retval;
+
+    if (!ret) {
+        return NULL;
+    }
+    qstring = qobject_to_qstring(ret);
+    if (!qstring) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "string");
+        retval = NULL;
+    } else {
+        retval = g_strdup(qstring_get_str(qstring));
+    }
+
+    QDECREF(qstring);
+    return retval;
+}
+
+void object_property_set_link(Object *obj, Object *value,
+                              const char *name, Error **errp)
+{
+    object_property_set_str(obj, object_get_canonical_path(value),
+                            name, errp);
+}
+
+Object *object_property_get_link(Object *obj, const char *name,
+                                 Error **errp)
+{
+    char *str = object_property_get_str(obj, name, errp);
+    Object *target = NULL;
+
+    if (str && *str) {
+        target = object_resolve_path(str, NULL);
+        if (!target) {
+            error_set(errp, QERR_DEVICE_NOT_FOUND, str);
+        }
+    }
+
+    g_free(str);
+    return target;
+}
+
+void object_property_set_bool(Object *obj, bool value,
+                              const char *name, Error **errp)
+{
+    QBool *qbool = qbool_from_int(value);
+    object_property_set_qobject(obj, QOBJECT(qbool), name, errp);
+
+    QDECREF(qbool);
+}
+
+bool object_property_get_bool(Object *obj, const char *name,
+                              Error **errp)
+{
+    QObject *ret = object_property_get_qobject(obj, name, errp);
+    QBool *qbool;
+    bool retval;
+
+    if (!ret) {
+        return false;
+    }
+    qbool = qobject_to_qbool(ret);
+    if (!qbool) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "boolean");
+        retval = false;
+    } else {
+        retval = qbool_get_int(qbool);
+    }
+
+    QDECREF(qbool);
+    return retval;
+}
+
+void object_property_set_int(Object *obj, int64_t value,
+                             const char *name, Error **errp)
+{
+    QInt *qint = qint_from_int(value);
+    object_property_set_qobject(obj, QOBJECT(qint), name, errp);
+
+    QDECREF(qint);
+}
+
+int64_t object_property_get_int(Object *obj, const char *name,
+                                Error **errp)
+{
+    QObject *ret = object_property_get_qobject(obj, name, errp);
+    QInt *qint;
+    int64_t retval;
+
+    if (!ret) {
+        return -1;
+    }
+    qint = qobject_to_qint(ret);
+    if (!qint) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "int");
+        retval = -1;
+    } else {
+        retval = qint_get_int(qint);
+    }
+
+    QDECREF(qint);
+    return retval;
+}
+
 const char *object_property_get_type(Object *obj, const char *name, Error **errp)
 {
     ObjectProperty *prop = object_property_find(obj, name);
@@ -695,6 +829,12 @@ void object_property_add_child(Object *obj, const char *name,
 {
     gchar *type;
 
+    /* Registering an interface object in the composition tree will mightily
+     * confuse object_get_canonical_path (which, on the other hand, knows how
+     * to get the canonical path of an interface object).
+     */
+    assert(!object_is_type(obj, type_interface));
+
     type = g_strdup_printf("child<%s>", object_get_typename(OBJECT(child)));
 
     object_property_add(obj, name, type, object_get_child_property,
@@ -730,6 +870,7 @@ static void object_set_link_property(Object *obj, Visitor *v, void *opaque,
     bool ambiguous = false;
     const char *type;
     char *path;
+    gchar *target_type;
 
     type = object_property_get_type(obj, name, NULL);
 
@@ -737,31 +878,30 @@ static void object_set_link_property(Object *obj, Visitor *v, void *opaque,
 
     if (*child) {
         object_unref(*child);
+        *child = NULL;
     }
 
     if (strcmp(path, "") != 0) {
         Object *target;
 
-        target = object_resolve_path(path, &ambiguous);
-        if (target) {
-            gchar *target_type;
-
-            target_type = g_strdup(&type[5]);
-            target_type[strlen(target_type) - 2] = 0;
+        /* Go from link<FOO> to FOO.  */
+        target_type = g_strndup(&type[5], strlen(type) - 6);
+        target = object_resolve_path_type(path, target_type, &ambiguous);
 
-            if (object_dynamic_cast(target, target_type)) {
-                object_ref(target);
-                *child = target;
+        if (ambiguous) {
+            error_set(errp, QERR_AMBIGUOUS_PATH, path);
+        } else if (target) {
+            object_ref(target);
+            *child = target;
+        } else {
+            target = object_resolve_path(path, &ambiguous);
+            if (target || ambiguous) {
+                error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, target_type);
             } else {
-                error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, type);
+                error_set(errp, QERR_DEVICE_NOT_FOUND, path);
             }
-
-            g_free(target_type);
-        } else {
-            error_set(errp, QERR_DEVICE_NOT_FOUND, path);
         }
-    } else {
-        *child = NULL;
+        g_free(target_type);
     }
 
     g_free(path);
@@ -788,6 +928,10 @@ gchar *object_get_canonical_path(Object *obj)
     Object *root = object_get_root();
     char *newpath = NULL, *path = NULL;
 
+    if (object_is_type(obj, type_interface)) {
+        obj = INTERFACE(obj)->obj;
+    }
+
     while (obj != root) {
         ObjectProperty *prop = NULL;
 
@@ -823,17 +967,18 @@ gchar *object_get_canonical_path(Object *obj)
 
 static Object *object_resolve_abs_path(Object *parent,
                                           gchar **parts,
+                                          const char *typename,
                                           int index)
 {
     ObjectProperty *prop;
     Object *child;
 
     if (parts[index] == NULL) {
-        return parent;
+        return object_dynamic_cast(parent, typename);
     }
 
     if (strcmp(parts[index], "") == 0) {
-        return object_resolve_abs_path(parent, parts, index + 1);
+        return object_resolve_abs_path(parent, parts, typename, index + 1);
     }
 
     prop = object_property_find(parent, parts[index]);
@@ -855,17 +1000,18 @@ static Object *object_resolve_abs_path(Object *parent,
         return NULL;
     }
 
-    return object_resolve_abs_path(child, parts, index + 1);
+    return object_resolve_abs_path(child, parts, typename, index + 1);
 }
 
 static Object *object_resolve_partial_path(Object *parent,
                                               gchar **parts,
+                                              const char *typename,
                                               bool *ambiguous)
 {
     Object *obj;
     ObjectProperty *prop;
 
-    obj = object_resolve_abs_path(parent, parts, 0);
+    obj = object_resolve_abs_path(parent, parts, typename, 0);
 
     QTAILQ_FOREACH(prop, &parent->properties, node) {
         Object *found;
@@ -874,7 +1020,8 @@ static Object *object_resolve_partial_path(Object *parent,
             continue;
         }
 
-        found = object_resolve_partial_path(prop->opaque, parts, ambiguous);
+        found = object_resolve_partial_path(prop->opaque, parts,
+                                            typename, ambiguous);
         if (found) {
             if (obj) {
                 if (ambiguous) {
@@ -893,7 +1040,8 @@ static Object *object_resolve_partial_path(Object *parent,
     return obj;
 }
 
-Object *object_resolve_path(const char *path, bool *ambiguous)
+Object *object_resolve_path_type(const char *path, const char *typename,
+                                 bool *ambiguous)
 {
     bool partial_path = true;
     Object *obj;
@@ -913,9 +1061,10 @@ Object *object_resolve_path(const char *path, bool *ambiguous)
         if (ambiguous) {
             *ambiguous = false;
         }
-        obj = object_resolve_partial_path(object_get_root(), parts, ambiguous);
+        obj = object_resolve_partial_path(object_get_root(), parts,
+                                          typename, ambiguous);
     } else {
-        obj = object_resolve_abs_path(object_get_root(), parts, 1);
+        obj = object_resolve_abs_path(object_get_root(), parts, typename, 1);
     }
 
     g_strfreev(parts);
@@ -923,14 +1072,19 @@ Object *object_resolve_path(const char *path, bool *ambiguous)
     return obj;
 }
 
+Object *object_resolve_path(const char *path, bool *ambiguous)
+{
+    return object_resolve_path_type(path, TYPE_OBJECT, ambiguous);
+}
+
 typedef struct StringProperty
 {
     char *(*get)(Object *, Error **);
     void (*set)(Object *, const char *, Error **);
 } StringProperty;
 
-static void object_property_get_str(Object *obj, Visitor *v, void *opaque,
-                                    const char *name, Error **errp)
+static void property_get_str(Object *obj, Visitor *v, void *opaque,
+                             const char *name, Error **errp)
 {
     StringProperty *prop = opaque;
     char *value;
@@ -942,8 +1096,8 @@ static void object_property_get_str(Object *obj, Visitor *v, void *opaque,
     }
 }
 
-static void object_property_set_str(Object *obj, Visitor *v, void *opaque,
-                                  const char *name, Error **errp)
+static void property_set_str(Object *obj, Visitor *v, void *opaque,
+                             const char *name, Error **errp)
 {
     StringProperty *prop = opaque;
     char *value;
@@ -959,8 +1113,8 @@ static void object_property_set_str(Object *obj, Visitor *v, void *opaque,
     g_free(value);
 }
 
-static void object_property_release_str(Object *obj, const char *name,
-                                      void *opaque)
+static void property_release_str(Object *obj, const char *name,
+                                 void *opaque)
 {
     StringProperty *prop = opaque;
     g_free(prop);
@@ -977,8 +1131,8 @@ void object_property_add_str(Object *obj, const char *name,
     prop->set = set;
 
     object_property_add(obj, name, "string",
-                        get ? object_property_get_str : NULL,
-                        set ? object_property_set_str : NULL,
-                        object_property_release_str,
+                        get ? property_get_str : NULL,
+                        set ? property_set_str : NULL,
+                        property_release_str,
                         prop, errp);
 }

qom/qom-qobject.c

+/*
+ * QEMU Object Model - QObject wrappers
+ *
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu-common.h"
+#include "qemu/object.h"
+#include "qemu/qom-qobject.h"
+#include "qapi/qapi-visit-core.h"
+#include "qapi/qmp-input-visitor.h"
+#include "qapi/qmp-output-visitor.h"
+
+void object_property_set_qobject(Object *obj, QObject *value,
+                                 const char *name, Error **errp)
+{
+    QmpInputVisitor *mi;
+    mi = qmp_input_visitor_new(value);
+    object_property_set(obj, qmp_input_get_visitor(mi), name, errp);
+
+    qmp_input_visitor_cleanup(mi);
+}
+
+QObject *object_property_get_qobject(Object *obj, const char *name,
+                                     Error **errp)
+{
+    QObject *ret = NULL;
+    Error *local_err = NULL;
+    QmpOutputVisitor *mo;
+
+    mo = qmp_output_visitor_new();
+    object_property_get(obj, qmp_output_get_visitor(mo), name, &local_err);
+    if (!local_err) {
+        ret = qmp_output_get_qobject(mo);
+    }
+    error_propagate(errp, local_err);
+    qmp_output_visitor_cleanup(mo);
+    return ret;
+}