Have a look at device_set_realized():
static void device_set_realized(Object *obj, bool value, Error **errp)
{
DeviceState *dev = DEVICE(obj);
DeviceClass *dc = DEVICE_GET_CLASS(dev);
HotplugHandler *hotplug_ctrl;
BusState *bus;
Error *local_err = NULL;
bool unattached_parent = false;
static int unattached_count;
if (dev->hotplugged && !dc->hotpluggable) {
error_setg(errp, QERR_DEVICE_NO_HOTPLUG, object_get_typename(obj));
return;
}
if (value && !dev->realized) {
[code to realize snipped...]
} else if (!value && dev->realized) {
/* We want local_err to track only the first error */
QLIST_FOREACH(bus, &dev->child_bus, sibling) {
[1] object_property_set_bool(OBJECT(bus), false, "realized",
local_err ? NULL : &local_err);
}
if (qdev_get_vmsd(dev)) {
[2] vmstate_unregister(VMSTATE_IF(dev), qdev_get_vmsd(dev), dev);
}
if (dc->unrealize) {
[3] dc->unrealize(dev, local_err ? NULL : &local_err);
}
dev->pending_deleted_event = true;
[4] DEVICE_LISTENER_CALL(unrealize, Reverse, dev);
if (local_err != NULL) {
goto fail;
}
}
assert(local_err == NULL);
dev->realized = value;
return;
[realize-only error handling snipped...]
fail:
error_propagate(errp, local_err);
if (unattached_parent) {
object_unparent(OBJECT(dev));
unattached_count--;
}
}
Can fail in two places: [1] a device on dev->child_bus fails to
unrealize, or [3] @dev itself fails to unrealize. We hold on to the
first failure, and continue to unrealize. device_set_realized() fails
when any of these fail.
Issue #1: What if some, but not all fail? How can this possibly work?
Issue #2: Even if all fail, and therefore both the device and the ones
on ->child_bus all remain realized, there are side effects at [2] and
[4].
Any better ideas than &error_abort?
