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qemu/hw/core/vm-change-state-handler.c

63 lines
2.0 KiB
C

/*
* qdev vm change state handlers
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License,
* or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "hw/qdev-core.h"
#include "sysemu/runstate.h"
static int qdev_get_dev_tree_depth(DeviceState *dev)
{
int depth;
for (depth = 0; dev; depth++) {
BusState *bus = dev->parent_bus;
if (!bus) {
break;
}
dev = bus->parent;
}
return depth;
}
/**
* qdev_add_vm_change_state_handler:
* @dev: the device that owns this handler
* @cb: the callback function to be invoked
* @opaque: user data passed to the callback function
*
* This function works like qemu_add_vm_change_state_handler() except callbacks
* are invoked in qdev tree depth order. Ordering is desirable when callbacks
* of children depend on their parent's callback having completed first.
*
* For example, when qdev_add_vm_change_state_handler() is used, a host
* controller's callback is invoked before the children on its bus when the VM
* starts running. The order is reversed when the VM stops running.
*
* Returns: an entry to be freed with qemu_del_vm_change_state_handler()
*/
VMChangeStateEntry *qdev_add_vm_change_state_handler(DeviceState *dev,
VMChangeStateHandler *cb,
void *opaque)
{
int depth = qdev_get_dev_tree_depth(dev);
return qemu_add_vm_change_state_handler_prio(cb, opaque, depth);
}