e965ffa70a
Children sometimes depend on their parent's vm change state handler having completed. Add a vm change state handler API for devices that guarantees tree depth ordering. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
62 lines
2.0 KiB
C
62 lines
2.0 KiB
C
/*
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* qdev vm change state handlers
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License,
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* or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "qemu/osdep.h"
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#include "hw/qdev.h"
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static int qdev_get_dev_tree_depth(DeviceState *dev)
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{
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int depth;
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for (depth = 0; dev; depth++) {
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BusState *bus = dev->parent_bus;
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if (!bus) {
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break;
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}
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dev = bus->parent;
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}
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return depth;
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}
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/**
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* qdev_add_vm_change_state_handler:
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* @dev: the device that owns this handler
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* @cb: the callback function to be invoked
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* @opaque: user data passed to the callback function
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*
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* This function works like qemu_add_vm_change_state_handler() except callbacks
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* are invoked in qdev tree depth order. Ordering is desirable when callbacks
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* of children depend on their parent's callback having completed first.
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*
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* For example, when qdev_add_vm_change_state_handler() is used, a host
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* controller's callback is invoked before the children on its bus when the VM
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* starts running. The order is reversed when the VM stops running.
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*
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* Returns: an entry to be freed with qemu_del_vm_change_state_handler()
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*/
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VMChangeStateEntry *qdev_add_vm_change_state_handler(DeviceState *dev,
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VMChangeStateHandler *cb,
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void *opaque)
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{
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int depth = qdev_get_dev_tree_depth(dev);
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return qemu_add_vm_change_state_handler_prio(cb, opaque, depth);
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}
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