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e0f300b36d
This patch adds the new VM state change cb type `VMChangeStateHandlerWithRet`, which has return value for `VMChangeStateEntry`. Thus, we can register a new VM state change cb with return value for device. Note that `VMChangeStateHandler` and `VMChangeStateHandlerWithRet` are mutually exclusive and cannot be provided at the same time. This patch is the pre patch for 'vhost-user: return failure if backend crashes when live migration', which makes the live migration aware of the loss of connection with the vhost-user backend and aborts the live migration. Virtio device will use VMChangeStateHandlerWithRet. Signed-off-by: Haoqian He <haoqian.he@smartx.com> Message-Id: <20250416024729.3289157-2-haoqian.he@smartx.com> Tested-by: Lei Yang <leiyang@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
80 lines
2.8 KiB
C
80 lines
2.8 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-core.h"
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#include "system/runstate.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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* @cb_ret: the callback function with return value 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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* Note that the parameter `cb` and `cb_ret` are mutually exclusive.
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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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VMChangeStateHandlerWithRet *cb_ret,
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void *opaque)
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{
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assert(!cb || !cb_ret);
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return qdev_add_vm_change_state_handler_full(dev, cb, NULL, cb_ret, opaque);
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}
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/*
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* Exactly like qdev_add_vm_change_state_handler() but passes a prepare_cb
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* and the cb_ret arguments too.
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*/
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VMChangeStateEntry *qdev_add_vm_change_state_handler_full(
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DeviceState *dev, VMChangeStateHandler *cb, VMChangeStateHandler *prepare_cb,
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VMChangeStateHandlerWithRet *cb_ret, void *opaque)
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{
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int depth = qdev_get_dev_tree_depth(dev);
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assert(!cb || !cb_ret);
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return qemu_add_vm_change_state_handler_prio_full(cb, prepare_cb, cb_ret,
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opaque, depth);
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}
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