vhost-user devices can get a disconnect in the middle of the VHOST-USER handshake on the migration start. If disconnect event happened right before sending next VHOST-USER command, then the vhost_dev_set_log() call in the vhost_migration_log() function will return error. This error will lead to the assert() and close the QEMU migration source process. For the vhost-user devices the disconnect event should not break the migration process, because: - the device will be in the stopped state, so it will not be changed during migration - if reconnect will be made the migration log will be reinitialized as part of reconnect/init process: #0 vhost_log_global_start (listener=0x563989cf7be0) at hw/virtio/vhost.c:920 #1 0x000056398603d8bc in listener_add_address_space (listener=0x563989cf7be0, as=0x563986ea4340 <address_space_memory>) at softmmu/memory.c:2664 #2 0x000056398603dd30 in memory_listener_register (listener=0x563989cf7be0, as=0x563986ea4340 <address_space_memory>) at softmmu/memory.c:2740 #3 0x0000563985fd6956 in vhost_dev_init (hdev=0x563989cf7bd8, opaque=0x563989cf7e30, backend_type=VHOST_BACKEND_TYPE_USER, busyloop_timeout=0) at hw/virtio/vhost.c:1385 #4 0x0000563985f7d0b8 in vhost_user_blk_connect (dev=0x563989cf7990) at hw/block/vhost-user-blk.c:315 #5 0x0000563985f7d3f6 in vhost_user_blk_event (opaque=0x563989cf7990, event=CHR_EVENT_OPENED) at hw/block/vhost-user-blk.c:379 Update the vhost-user-blk device with the internal started_vu field which will be used for initialization (vhost_user_blk_start) and clean up (vhost_user_blk_stop). This additional flag in the VhostUserBlk structure will be used to track whether the device really needs to be stopped and cleaned up on a vhost-user level. The disconnect event will set the overall VHOST device (not vhost-user) to the stopped state, so it can be used by the general vhost_migration_log routine. Such approach could be propogated to the other vhost-user devices, but better idea is just to make the same connect/disconnect code for all the vhost-user devices. This migration issue was slightly discussed earlier: - https://lists.gnu.org/archive/html/qemu-devel/2020-05/msg01509.html - https://lists.gnu.org/archive/html/qemu-devel/2020-05/msg05241.html Signed-off-by: Dima Stepanov <dimastep@yandex-team.ru> Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com> Message-Id: <9fbfba06791a87813fcee3e2315f0b904cc6789a.1599813294.git.dimastep@yandex-team.ru> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
57 lines
1.5 KiB
C
57 lines
1.5 KiB
C
/*
|
|
* vhost-user-blk host device
|
|
* Copyright(C) 2017 Intel Corporation.
|
|
*
|
|
* Authors:
|
|
* Changpeng Liu <changpeng.liu@intel.com>
|
|
*
|
|
* Based on vhost-scsi.h, Copyright IBM, Corp. 2011
|
|
*
|
|
* This work is licensed under the terms of the GNU LGPL, version 2 or later.
|
|
* See the COPYING.LIB file in the top-level directory.
|
|
*
|
|
*/
|
|
|
|
#ifndef VHOST_USER_BLK_H
|
|
#define VHOST_USER_BLK_H
|
|
|
|
#include "standard-headers/linux/virtio_blk.h"
|
|
#include "hw/block/block.h"
|
|
#include "chardev/char-fe.h"
|
|
#include "hw/virtio/vhost.h"
|
|
#include "hw/virtio/vhost-user.h"
|
|
#include "qom/object.h"
|
|
|
|
#define TYPE_VHOST_USER_BLK "vhost-user-blk"
|
|
OBJECT_DECLARE_SIMPLE_TYPE(VHostUserBlk, VHOST_USER_BLK)
|
|
|
|
#define VHOST_USER_BLK_AUTO_NUM_QUEUES UINT16_MAX
|
|
|
|
struct VHostUserBlk {
|
|
VirtIODevice parent_obj;
|
|
CharBackend chardev;
|
|
int32_t bootindex;
|
|
struct virtio_blk_config blkcfg;
|
|
uint16_t num_queues;
|
|
uint32_t queue_size;
|
|
uint32_t config_wce;
|
|
struct vhost_dev dev;
|
|
struct vhost_inflight *inflight;
|
|
VhostUserState vhost_user;
|
|
struct vhost_virtqueue *vhost_vqs;
|
|
VirtQueue **virtqs;
|
|
|
|
/*
|
|
* There are at least two steps of initialization of the
|
|
* vhost-user device. The first is a "connect" step and
|
|
* second is a "start" step. Make a separation between
|
|
* those initialization phases by using two fields.
|
|
*/
|
|
/* vhost_user_blk_connect/vhost_user_blk_disconnect */
|
|
bool connected;
|
|
/* vhost_user_blk_start/vhost_user_blk_stop */
|
|
bool started_vu;
|
|
};
|
|
|
|
#endif
|