xref: /qemu/hw/core/vm-change-state-handler.c (revision a27bd6c779badb8d76e4430d810ef710a1b98f4e)
1e965ffa7SStefan Hajnoczi /*
2e965ffa7SStefan Hajnoczi  *  qdev vm change state handlers
3e965ffa7SStefan Hajnoczi  *
4e965ffa7SStefan Hajnoczi  *  This program is free software; you can redistribute it and/or modify
5e965ffa7SStefan Hajnoczi  *  it under the terms of the GNU General Public License as published by
6e965ffa7SStefan Hajnoczi  *  the Free Software Foundation; either version 2 of the License,
7e965ffa7SStefan Hajnoczi  *  or (at your option) any later version.
8e965ffa7SStefan Hajnoczi  *
9e965ffa7SStefan Hajnoczi  *  This program is distributed in the hope that it will be useful,
10e965ffa7SStefan Hajnoczi  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
11e965ffa7SStefan Hajnoczi  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12e965ffa7SStefan Hajnoczi  *  GNU General Public License for more details.
13e965ffa7SStefan Hajnoczi  *
14e965ffa7SStefan Hajnoczi  *  You should have received a copy of the GNU General Public License
15e965ffa7SStefan Hajnoczi  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
16e965ffa7SStefan Hajnoczi  */
17e965ffa7SStefan Hajnoczi 
18e965ffa7SStefan Hajnoczi #include "qemu/osdep.h"
19*a27bd6c7SMarkus Armbruster #include "hw/qdev-core.h"
20e965ffa7SStefan Hajnoczi 
21e965ffa7SStefan Hajnoczi static int qdev_get_dev_tree_depth(DeviceState *dev)
22e965ffa7SStefan Hajnoczi {
23e965ffa7SStefan Hajnoczi     int depth;
24e965ffa7SStefan Hajnoczi 
25e965ffa7SStefan Hajnoczi     for (depth = 0; dev; depth++) {
26e965ffa7SStefan Hajnoczi         BusState *bus = dev->parent_bus;
27e965ffa7SStefan Hajnoczi 
28e965ffa7SStefan Hajnoczi         if (!bus) {
29e965ffa7SStefan Hajnoczi             break;
30e965ffa7SStefan Hajnoczi         }
31e965ffa7SStefan Hajnoczi 
32e965ffa7SStefan Hajnoczi         dev = bus->parent;
33e965ffa7SStefan Hajnoczi     }
34e965ffa7SStefan Hajnoczi 
35e965ffa7SStefan Hajnoczi     return depth;
36e965ffa7SStefan Hajnoczi }
37e965ffa7SStefan Hajnoczi 
38e965ffa7SStefan Hajnoczi /**
39e965ffa7SStefan Hajnoczi  * qdev_add_vm_change_state_handler:
40e965ffa7SStefan Hajnoczi  * @dev: the device that owns this handler
41e965ffa7SStefan Hajnoczi  * @cb: the callback function to be invoked
42e965ffa7SStefan Hajnoczi  * @opaque: user data passed to the callback function
43e965ffa7SStefan Hajnoczi  *
44e965ffa7SStefan Hajnoczi  * This function works like qemu_add_vm_change_state_handler() except callbacks
45e965ffa7SStefan Hajnoczi  * are invoked in qdev tree depth order.  Ordering is desirable when callbacks
46e965ffa7SStefan Hajnoczi  * of children depend on their parent's callback having completed first.
47e965ffa7SStefan Hajnoczi  *
48e965ffa7SStefan Hajnoczi  * For example, when qdev_add_vm_change_state_handler() is used, a host
49e965ffa7SStefan Hajnoczi  * controller's callback is invoked before the children on its bus when the VM
50e965ffa7SStefan Hajnoczi  * starts running.  The order is reversed when the VM stops running.
51e965ffa7SStefan Hajnoczi  *
52e965ffa7SStefan Hajnoczi  * Returns: an entry to be freed with qemu_del_vm_change_state_handler()
53e965ffa7SStefan Hajnoczi  */
54e965ffa7SStefan Hajnoczi VMChangeStateEntry *qdev_add_vm_change_state_handler(DeviceState *dev,
55e965ffa7SStefan Hajnoczi                                                      VMChangeStateHandler *cb,
56e965ffa7SStefan Hajnoczi                                                      void *opaque)
57e965ffa7SStefan Hajnoczi {
58e965ffa7SStefan Hajnoczi     int depth = qdev_get_dev_tree_depth(dev);
59e965ffa7SStefan Hajnoczi 
60e965ffa7SStefan Hajnoczi     return qemu_add_vm_change_state_handler_prio(cb, opaque, depth);
61e965ffa7SStefan Hajnoczi }
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