From: Xie Yongji <xieyon...@baidu.com>
This patchset is aimed at supporting qemu to reconnect
vhost-user-blk backend after vhost-user-blk backend crash or
restart.
The patch 1 uses exisiting wait/nowait options to make QEMU not
do a connect on client sockets during initialization of the chardev.
The patch 2 introduces two new messages VHOST_USER_GET_INFLIGHT_FD
and VHOST_USER_SET_INFLIGHT_FD to support providing shared
memory to backend.
The patch 3,4 are the corresponding libvhost-user patches of
patch 2. Make libvhost-user support VHOST_USER_GET_INFLIGHT_FD
and VHOST_USER_SET_INFLIGHT_FD.
The patch 5 allows vhost-user-blk to use the two new messages
to get/set inflight buffer from/to backend.
The patch 6 supports vhost-user-blk to reconnect backend when
connection closed.
The patch 7 introduces VHOST_USER_PROTOCOL_F_SLAVE_SHMFD
to vhost-user-blk backend which is used to tell qemu that
we support reconnecting now.
To use it, we could start qemu with:
qemu-system-x86_64 \
-chardev socket,id=char0,path=/path/vhost.socket,nowait,reconnect=1, \
-device vhost-user-blk-pci,chardev=char0 \
and start vhost-user-blk backend with:
vhost-user-blk -b /path/file -s /path/vhost.socket
Then we can restart vhost-user-blk at any time during VM running.
V3 to V4:
- Drop messages VHOST_USER_GET_SHM_SIZE and VHOST_USER_SET_SHM_FD
- Introduce two new messages VHOST_USER_GET_INFLIGHT_FD
and VHOST_USER_SET_INFLIGHT_FD
- Allocate inflight buffer in backend rather than in qemu
- Document a recommended format for inflight buffer
V2 to V3:
- Using exisiting wait/nowait options to control connection on
client sockets instead of introducing "disconnected" option.
- Support the case that vhost-user backend restart during initialzation
of vhost-user-blk device.
V1 to V2:
- Introduce "disconnected" option for chardev instead of reuse "wait"
option
- Support the case that QEMU starts before vhost-user backend
- Drop message VHOST_USER_SET_VRING_INFLIGHT
- Introduce two new messages VHOST_USER_GET_SHM_SIZE
and VHOST_USER_SET_SHM_FD
Xie Yongji (7):
char-socket: Enable "nowait" option on client sockets
vhost-user: Support transferring inflight buffer between qemu and
backend
libvhost-user: Introduce vu_queue_map_desc()
libvhost-user: Support tracking inflight I/O in shared memory
vhost-user-blk: Add support to get/set inflight buffer
vhost-user-blk: Add support to reconnect backend
contrib/vhost-user-blk: enable inflight I/O tracking
Makefile | 2 +-
chardev/char-socket.c | 56 ++--
contrib/libvhost-user/libvhost-user.c | 346 ++++++++++++++++++++----
contrib/libvhost-user/libvhost-user.h | 29 ++
contrib/vhost-user-blk/vhost-user-blk.c | 3 +-
docs/interop/vhost-user.txt | 60 ++++
hw/block/vhost-user-blk.c | 223 ++++++++++++---
hw/virtio/vhost-user.c | 108 ++++++++
hw/virtio/vhost.c | 108 ++++++++
include/hw/virtio/vhost-backend.h | 9 +
include/hw/virtio/vhost-user-blk.h | 5 +
include/hw/virtio/vhost.h | 19 ++
qapi/char.json | 3 +-
qemu-options.hx | 9 +-
14 files changed, 851 insertions(+), 129 deletions(-)
--
2.17.1
