On 2018/12/6 下午2:35, elohi...@gmail.com wrote:
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 tries to implenment the sync connection for
"reconnect socket".
The patch 2 introduces a new message VHOST_USER_SET_VRING_INFLIGHT
to support offering shared memory to backend to record
its inflight I/O.
The patch 3,4 are the corresponding libvhost-user patches of
patch 2. Make libvhost-user support VHOST_USER_SET_VRING_INFLIGHT.
The patch 5 supports vhost-user-blk to reconnect backend when
connection closed.
The patch 6 tells 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,reconnect=1,wait \
-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.
I wonder whether or not it's better to handle this at the level of
virtio protocol itself instead of vhost-user level. E.g expose
last_avail_idx to driver might be sufficient?
Another possible issue is, looks like you need to deal with different
kinds of ring layouts e.g packed virtqueues.
Thanks
Xie Yongji (6):
char-socket: Enable "wait" option for client mode
vhost-user: Add shared memory to record inflight I/O
libvhost-user: Introduce vu_queue_map_desc()
libvhost-user: Support recording inflight I/O in shared memory
vhost-user-blk: Add support for reconnecting backend
contrib/vhost-user-blk: enable inflight I/O recording
chardev/char-socket.c | 5 +-
contrib/libvhost-user/libvhost-user.c | 215 ++++++++++++++++++++----
contrib/libvhost-user/libvhost-user.h | 19 +++
contrib/vhost-user-blk/vhost-user-blk.c | 3 +-
hw/block/vhost-user-blk.c | 169 +++++++++++++++++--
hw/virtio/vhost-user.c | 69 ++++++++
hw/virtio/vhost.c | 8 +
include/hw/virtio/vhost-backend.h | 4 +
include/hw/virtio/vhost-user-blk.h | 4 +
include/hw/virtio/vhost-user.h | 8 +
10 files changed, 452 insertions(+), 52 deletions(-)
