QOM & QDev patches

- Remove DeviceState::opts (Akihiko)
 - Replace container_get by machine/object_get_container (Peter)
 - Remove InterfaceInfo::concrete_class field (Paolo)
 - Reduce machine_containers[] scope (Philippe)
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 =+TLu
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Merge tag 'qom-qdev-20250109' of https://github.com/philmd/qemu into staging

QOM & QDev patches

- Remove DeviceState::opts (Akihiko)
- Replace container_get by machine/object_get_container (Peter)
- Remove InterfaceInfo::concrete_class field (Paolo)
- Reduce machine_containers[] scope (Philippe)

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# KTtapCVsong5JzYZWhITNCMf5w2YGCJGJJekxdrqBvFk+FkMR38=
# =+TLu
# -----END PGP SIGNATURE-----
# gpg: Signature made Thu 09 Jan 2025 12:18:16 EST
# gpg:                using RSA key FAABE75E12917221DCFD6BB2E3E32C2CDEADC0DE
# gpg: Good signature from "Philippe Mathieu-Daudé (F4BUG) <f4bug@amsat.org>" [full]
# Primary key fingerprint: FAAB E75E 1291 7221 DCFD  6BB2 E3E3 2C2C DEAD C0DE

* tag 'qom-qdev-20250109' of https://github.com/philmd/qemu:
  system: Inline machine_containers[] in qemu_create_machine_containers()
  qom: remove unused InterfaceInfo::concrete_class field
  qom: Remove container_get()
  qom: Use object_get_container()
  qom: Add object_get_container()
  qdev: Use machine_get_container()
  qdev: Add machine_get_container()
  qdev: Make qdev_get_machine() not use container_get()
  qdev: Implement qdev_create_fake_machine() for user emulation
  qdev: Remove opts member
  hw/pci: Use -1 as the default value for rombar

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

accel/tcg/tcg-all.c

@@ -35,7 +35,9 @@
 #include "qemu/atomic.h"
 #include "qapi/qapi-builtin-visit.h"
 #include "qemu/units.h"
-#if !defined(CONFIG_USER_ONLY)
+#if defined(CONFIG_USER_ONLY)
+#include "hw/qdev-core.h"
+#else
 #include "hw/boards.h"
 #endif
 #include "internal-common.h"
@@ -124,6 +126,10 @@ static int tcg_init_machine(MachineState *ms)
     tcg_prologue_init();
 #endif
 
+#ifdef CONFIG_USER_ONLY
+    qdev_create_fake_machine();
+#endif
+
     return 0;
 }
 

backends/cryptodev.c

@@ -97,7 +97,7 @@ static int qmp_query_cryptodev_foreach(Object *obj, void *data)
 QCryptodevInfoList *qmp_query_cryptodev(Error **errp)
 {
     QCryptodevInfoList *list = NULL;
-    Object *objs = container_get(object_get_root(), "/objects");
+    Object *objs = object_get_container("objects");
 
     object_child_foreach(objs, qmp_query_cryptodev_foreach, &list);
 
@@ -557,7 +557,7 @@ static void cryptodev_backend_stats_cb(StatsResultList **result,
     switch (target) {
     case STATS_TARGET_CRYPTODEV:
     {
-        Object *objs = container_get(object_get_root(), "/objects");
+        Object *objs = object_get_container("objects");
         StatsArgs stats_args;
         stats_args.result.stats = result;
         stats_args.names = names;

chardev/char.c

@@ -48,7 +48,7 @@
 
 Object *get_chardevs_root(void)
 {
-    return container_get(object_get_root(), "/chardevs");
+    return object_get_container("chardevs");
 }
 
 static void chr_be_event(Chardev *s, QEMUChrEvent event)

hw/core/gpio.c

@@ -121,8 +121,7 @@ void qdev_connect_gpio_out_named(DeviceState *dev, const char *name, int n,
                                      name ? name : "unnamed-gpio-out", n);
     if (input_pin && !OBJECT(input_pin)->parent) {
         /* We need a name for object_property_set_link to work */
-        object_property_add_child(container_get(qdev_get_machine(),
+        object_property_add_child(machine_get_container("unattached"),
-                                                "/unattached"),
                                   "non-qdev-gpio[*]", OBJECT(input_pin));
     }
     object_property_set_link(OBJECT(dev), propname,

hw/core/meson.build

@@ -46,3 +46,4 @@ system_ss.add(files(
   'vm-change-state-handler.c',
   'clock-vmstate.c',
 ))
+user_ss.add(files('qdev-user.c'))

hw/core/qdev-user.c

@@ -0,0 +1,19 @@
+/*
+ * QDev helpers specific to user emulation.
+ *
+ * Copyright 2025 Linaro, Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#include "qemu/osdep.h"
+#include "qom/object.h"
+#include "hw/qdev-core.h"
+
+void qdev_create_fake_machine(void)
+{
+    Object *fake_machine_obj;
+
+    fake_machine_obj = object_property_add_new_container(object_get_root(),
+                                                         "machine");
+    object_property_add_new_container(fake_machine_obj, "unattached");
+}

hw/core/qdev.c

@@ -476,8 +476,7 @@ static void device_set_realized(Object *obj, bool value, Error **errp)
         if (!obj->parent) {
             gchar *name = g_strdup_printf("device[%d]", unattached_count++);
 
-            object_property_add_child(container_get(qdev_get_machine(),
+            object_property_add_child(machine_get_container("unattached"),
-                                                    "/unattached"),
                                       name, obj);
             unattached_parent = true;
             g_free(name);
@@ -691,7 +690,6 @@ static void device_finalize(Object *obj)
         dev->canonical_path = NULL;
     }
 
-    qobject_unref(dev->opts);
     g_free(dev->id);
 }
 
@@ -818,12 +816,28 @@ Object *qdev_get_machine(void)
     static Object *dev;
 
     if (dev == NULL) {
-        dev = container_get(object_get_root(), "/machine");
+        dev = object_resolve_path_component(object_get_root(), "machine");
+        /*
+         * Any call to this function before machine is created is treated
+         * as a programming error as of now.
+         */
+        assert(dev);
     }
 
     return dev;
 }
 
+Object *machine_get_container(const char *name)
+{
+    Object *container, *machine;
+
+    machine = qdev_get_machine();
+    container = object_resolve_path_component(machine, name);
+    assert(object_dynamic_cast(container, TYPE_CONTAINER));
+
+    return container;
+}
+
 char *qdev_get_human_name(DeviceState *dev)
 {
     g_assert(dev != NULL);

hw/core/sysbus.c

@@ -65,9 +65,9 @@ void foreach_dynamic_sysbus_device(FindSysbusDeviceFunc *func, void *opaque)
     };
 
     /* Loop through all sysbus devices that were spawned outside the machine */
-    container = container_get(qdev_get_machine(), "/peripheral");
+    container = machine_get_container("peripheral");
     find_sysbus_device(container, &find);
-    container = container_get(qdev_get_machine(), "/peripheral-anon");
+    container = machine_get_container("peripheral-anon");
     find_sysbus_device(container, &find);
 }
 

hw/i386/pc.c

@@ -463,7 +463,7 @@ static int check_fdc(Object *obj, void *opaque)
 }
 
 static const char * const fdc_container_path[] = {
-    "/unattached", "/peripheral", "/peripheral-anon"
+    "unattached", "peripheral", "peripheral-anon"
 };
 
 /*
@@ -477,7 +477,7 @@ static ISADevice *pc_find_fdc0(void)
     CheckFdcState state = { 0 };
 
     for (i = 0; i < ARRAY_SIZE(fdc_container_path); i++) {
-        container = container_get(qdev_get_machine(), fdc_container_path[i]);
+        container = machine_get_container(fdc_container_path[i]);
         object_child_foreach(container, check_fdc, &state);
     }
 

hw/pci/pci.c

@@ -85,7 +85,7 @@ static const Property pci_props[] = {
     DEFINE_PROP_PCI_DEVFN("addr", PCIDevice, devfn, -1),
     DEFINE_PROP_STRING("romfile", PCIDevice, romfile),
     DEFINE_PROP_UINT32("romsize", PCIDevice, romsize, UINT32_MAX),
-    DEFINE_PROP_UINT32("rombar",  PCIDevice, rom_bar, 1),
+    DEFINE_PROP_INT32("rombar",  PCIDevice, rom_bar, -1),
     DEFINE_PROP_BIT("multifunction", PCIDevice, cap_present,
                     QEMU_PCI_CAP_MULTIFUNCTION_BITNR, false),
     DEFINE_PROP_BIT("x-pcie-lnksta-dllla", PCIDevice, cap_present,

hw/vfio/pci.c

@@ -1012,7 +1012,6 @@ static void vfio_pci_size_rom(VFIOPCIDevice *vdev)
 {
     uint32_t orig, size = cpu_to_le32((uint32_t)PCI_ROM_ADDRESS_MASK);
     off_t offset = vdev->config_offset + PCI_ROM_ADDRESS;
-    DeviceState *dev = DEVICE(vdev);
     char *name;
     int fd = vdev->vbasedev.fd;
 
@@ -1046,12 +1045,12 @@ static void vfio_pci_size_rom(VFIOPCIDevice *vdev)
     }
 
     if (vfio_opt_rom_in_denylist(vdev)) {
-        if (dev->opts && qdict_haskey(dev->opts, "rombar")) {
+        if (vdev->pdev.rom_bar > 0) {
             warn_report("Device at %s is known to cause system instability"
                         " issues during option rom execution",
                         vdev->vbasedev.name);
             error_printf("Proceeding anyway since user specified"
-                         " non zero value for rombar\n");
+                         " positive value for rombar\n");
         } else {
             warn_report("Rom loading for device at %s has been disabled"
                         " due to system instability issues",

include/hw/pci/pci_device.h

@@ -148,7 +148,7 @@ struct PCIDevice {
     uint32_t romsize;
     bool has_rom;
     MemoryRegion rom;
-    uint32_t rom_bar;
+    int32_t rom_bar;
 
     /* INTx routing notifier */
     PCIINTxRoutingNotifier intx_routing_notifier;

include/hw/qdev-core.h

@@ -248,10 +248,6 @@ struct DeviceState {
      * @pending_deleted_expires_ms: optional timeout for deletion events
      */
     int64_t pending_deleted_expires_ms;
-    /**
-     * @opts: QDict of options for the device
-     */
-    QDict *opts;
     /**
      * @hotplugged: was device added after PHASE_MACHINE_READY?
      */
@@ -1027,6 +1023,26 @@ const char *qdev_fw_name(DeviceState *dev);
 void qdev_assert_realized_properly(void);
 Object *qdev_get_machine(void);
 
+/**
+ * qdev_create_fake_machine(): Create a fake machine container.
+ *
+ * .. note::
+ *    This function is a kludge for user emulation (USER_ONLY)
+ *    because when thread (TYPE_CPU) are realized, qdev_realize()
+ *    access a machine container.
+ */
+void qdev_create_fake_machine(void);
+
+/**
+ * machine_get_container:
+ * @name: The name of container to lookup
+ *
+ * Get a container of the machine (QOM path "/machine/NAME").
+ *
+ * Returns: the machine container object.
+ */
+Object *machine_get_container(const char *name);
+
 /**
  * qdev_get_human_name() - Return a human-readable name for a device
  * @dev: The device. Must be a valid and non-NULL pointer.

include/qom/object.h

@@ -573,12 +573,15 @@ struct InterfaceInfo {
  *
  * The class for all interfaces.  Subclasses of this class should only add
  * virtual methods.
+ *
+ * Note that most of the fields of ObjectClass are unused (all except
+ * "type", in fact).  They are only present in InterfaceClass to allow
+ * @object_class_dynamic_cast to work with both regular classes and interfaces.
  */
 struct InterfaceClass
 {
     ObjectClass parent_class;
     /* private: */
-    ObjectClass *concrete_class;
     Type interface_type;
 };
 
@@ -1510,6 +1513,16 @@ const char *object_property_get_type(Object *obj, const char *name,
  */
 Object *object_get_root(void);
 
+/**
+ * object_get_container:
+ * @name: the name of container to lookup
+ *
+ * Lookup a root level container.
+ *
+ * Returns: the container with @name.
+ */
+Object *object_get_container(const char *name);
+
 
 /**
  * object_get_objects_root:
@@ -2007,17 +2020,6 @@ int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
 int object_child_foreach_recursive(Object *obj,
                                    int (*fn)(Object *child, void *opaque),
                                    void *opaque);
-/**
- * container_get:
- * @root: root of the #path, e.g., object_get_root()
- * @path: path to the container
- *
- * Return a container object whose path is @path.  Create more containers
- * along the path if necessary.
- *
- * Returns: the container object.
- */
-Object *container_get(Object *root, const char *path);
 
 /**
  * object_property_add_new_container:

qom/container.c

@@ -34,27 +34,4 @@ Object *object_property_add_new_container(Object *obj, const char *name)
     return child;
 }
 
-Object *container_get(Object *root, const char *path)
-{
-    Object *obj, *child;
-    char **parts;
-    int i;
-
-    parts = g_strsplit(path, "/", 0);
-    assert(parts != NULL && parts[0] != NULL && !parts[0][0]);
-    obj = root;
-
-    for (i = 1; parts[i] != NULL; i++, obj = child) {
-        child = object_resolve_path_component(obj, parts[i]);
-        if (!child) {
-            child = object_property_add_new_container(obj, parts[i]);
-        }
-    }
-
-    g_strfreev(parts);
-
-    return obj;
-}
-
-
 type_init(container_register_types)

qom/object.c

@@ -314,7 +314,6 @@ static void type_initialize_interface(TypeImpl *ti, TypeImpl *interface_type,
     g_free((char *)info.name);
 
     new_iface = (InterfaceClass *)iface_impl->class;
-    new_iface->concrete_class = ti->class;
     new_iface->interface_type = interface_type;
 
     ti->class->interfaces = g_slist_append(ti->class->interfaces, new_iface);
@@ -1751,6 +1750,16 @@ static Object *object_root_initialize(void)
     return root;
 }
 
+Object *object_get_container(const char *name)
+{
+    Object *container;
+
+    container = object_resolve_path_component(object_get_root(), name);
+    assert(object_dynamic_cast(container, TYPE_CONTAINER));
+
+    return container;
+}
+
 Object *object_get_root(void)
 {
     static Object *root;
@@ -1764,7 +1773,7 @@ Object *object_get_root(void)
 
 Object *object_get_objects_root(void)
 {
-    return container_get(object_get_root(), "/objects");
+    return object_get_container("objects");
 }
 
 Object *object_get_internal_root(void)

scsi/pr-manager.c

@@ -21,7 +21,7 @@
 #include "qemu/module.h"
 #include "qapi/qapi-commands-block.h"
 
-#define PR_MANAGER_PATH     "/objects"
+#define PR_MANAGER_PATH     "objects"
 
 typedef struct PRManagerData {
     PRManager *pr_mgr;
@@ -135,7 +135,7 @@ PRManagerInfoList *qmp_query_pr_managers(Error **errp)
 {
     PRManagerInfoList *head = NULL;
     PRManagerInfoList **prev = &head;
-    Object *container = container_get(object_get_root(), PR_MANAGER_PATH);
+    Object *container = object_get_container(PR_MANAGER_PATH);
 
     object_child_foreach(container, query_one_pr_manager, &prev);
     return head;

system/ioport.c

@@ -258,7 +258,7 @@ static void portio_list_add_1(PortioList *piolist,
     object_ref(&mrpio->mr);
     object_unparent(OBJECT(&mrpio->mr));
     if (!piolist->owner) {
-        owner = container_get(qdev_get_machine(), "/unattached");
+        owner = machine_get_container("unattached");
     } else {
         owner = piolist->owner;
     }

system/memory.c

@@ -1238,7 +1238,7 @@ static void memory_region_do_init(MemoryRegion *mr,
         char *name_array = g_strdup_printf("%s[*]", escaped_name);
 
         if (!owner) {
-            owner = container_get(qdev_get_machine(), "/unattached");
+            owner = machine_get_container("unattached");
         }
 
         object_property_add_child(owner, name_array, OBJECT(mr));

system/qdev-monitor.c

@@ -348,7 +348,7 @@ static Object *qdev_get_peripheral(void)
     static Object *dev;
 
     if (dev == NULL) {
-        dev = container_get(qdev_get_machine(), "/peripheral");
+        dev = machine_get_container("peripheral");
     }
 
     return dev;
@@ -359,7 +359,7 @@ static Object *qdev_get_peripheral_anon(void)
     static Object *dev;
 
     if (dev == NULL) {
-        dev = container_get(qdev_get_machine(), "/peripheral-anon");
+        dev = machine_get_container("peripheral-anon");
     }
 
     return dev;
@@ -631,6 +631,7 @@ DeviceState *qdev_device_add_from_qdict(const QDict *opts,
     char *id;
     DeviceState *dev = NULL;
     BusState *bus = NULL;
+    QDict *properties;
 
     driver = qdict_get_try_str(opts, "driver");
     if (!driver) {
@@ -712,13 +713,14 @@ DeviceState *qdev_device_add_from_qdict(const QDict *opts,
     }
 
     /* set properties */
-    dev->opts = qdict_clone_shallow(opts);
+    properties = qdict_clone_shallow(opts);
-    qdict_del(dev->opts, "driver");
+    qdict_del(properties, "driver");
-    qdict_del(dev->opts, "bus");
+    qdict_del(properties, "bus");
-    qdict_del(dev->opts, "id");
+    qdict_del(properties, "id");
 
-    object_set_properties_from_keyval(&dev->parent_obj, dev->opts, from_json,
+    object_set_properties_from_keyval(&dev->parent_obj, properties, from_json,
                                       errp);
+    qobject_unref(properties);
     if (*errp) {
         goto err_del_dev;
     }
@@ -1098,7 +1100,7 @@ static GSList *qdev_build_hotpluggable_device_list(Object *peripheral)
 static void peripheral_device_del_completion(ReadLineState *rs,
                                              const char *str)
 {
-    Object *peripheral = container_get(qdev_get_machine(), "/peripheral");
+    Object *peripheral = machine_get_container("peripheral");
     GSList *list, *item;
 
     list = qdev_build_hotpluggable_device_list(peripheral);

system/vl.c

@@ -2113,18 +2113,16 @@ static void parse_memory_options(void)
     loc_pop(&loc);
 }
 
-static const char *const machine_containers[] = {
-    "unattached",
-    "peripheral",
-    "peripheral-anon"
-};
-
 static void qemu_create_machine_containers(Object *machine)
 {
-    int i;
+    static const char *const containers[] = {
+        "unattached",
+        "peripheral",
+        "peripheral-anon",
+    };
 
-    for (i = 0; i < ARRAY_SIZE(machine_containers); i++) {
+    for (unsigned i = 0; i < ARRAY_SIZE(containers); i++) {
-        object_property_add_new_container(machine, machine_containers[i]);
+        object_property_add_new_container(machine, containers[i]);
     }
 }
 
@@ -2137,8 +2135,7 @@ static void qemu_create_machine(QDict *qdict)
     object_property_add_child(object_get_root(), "machine",
                               OBJECT(current_machine));
     qemu_create_machine_containers(OBJECT(current_machine));
-    object_property_add_child(container_get(OBJECT(current_machine),
+    object_property_add_child(machine_get_container("unattached"),
-                                            "/unattached"),
                               "sysbus", OBJECT(sysbus_get_default()));
 
     if (machine_class->minimum_page_bits) {

ui/console.c

@@ -1160,7 +1160,7 @@ DisplayState *init_displaystate(void)
          * all QemuConsoles are created and the order / numbering
          * doesn't change any more */
         name = g_strdup_printf("console[%d]", con->index);
-        object_property_add_child(container_get(object_get_root(), "/backend"),
+        object_property_add_child(object_get_container("backend"),
                                   name, OBJECT(con));
         g_free(name);
     }

ui/dbus-chardev.c

@@ -106,7 +106,7 @@ dbus_chardev_init(DBusDisplay *dpy)
     dpy->notifier.notify = dbus_display_on_notify;
     dbus_display_notifier_add(&dpy->notifier);
 
-    object_child_foreach(container_get(object_get_root(), "/chardevs"),
+    object_child_foreach(object_get_container("chardevs"),
                          dbus_display_chardev_foreach, dpy);
 }