On Thu, Aug 16, 2018 at 5:32 PM, Yury Kotov <yury-ko...@yandex-team.ru> wrote: > We are using QEMU (2.12.0) with SPDK (18.04.1) over vhost-user to emulate > block > devices. One of our cases it to restart SPDK without restarting VM (in case > of some updates or smth like it). We tried to use the 'reconnect' option for > the '-chardev' device: > -object > memory-backend-file,id=mem0,size=1G,mem-path=/dev/hugepages,share=on \ > -numa node,memdev=mem0 \ > -chardev socket,id=spdk_vhost_blk1,path=/var/tmp/vhost.1,reconnect=10 \ > -device vhost-user-blk-pci,chardev=spdk_vhost_blk1,num-queues=4 > > After this, vhost-user-blk initialization fails with an error below: > qemu-system-x86_64: -device ...: Failed to set msg fds. > qemu-system-x86_64: -device ...: vhost-user-blk: vhost initialization > failed: > Operation not permitted > > We got the same error with the latest QEMU (c542a9f9794ec8e0bc3f). > > We made some investigations and found out that there are several issues: > > 1. Reconnect option postpones the first connection till machine init done > event. > But we need this connection during vhost blk device initialization which > happens before the machine init done handling. > > 2. If the connection is forced, then the reconnection will be successful > after SPDK restart. The problem is that virtual queue will not start. > The reason for it is that virtual queue initialization commands > should be resent: > * VHOST_USER_SET_FEATURES > * VHOST_USER_SET_MEM_TABLE > * VHOST_USER_SET_VRING_NUM > * VHOST_USER_SET_VRING_BASE > * VHOST_USER_SET_VRING_ADDR > * VHOST_USER_SET_VRING_KICK > * VHOST_USER_SET_VRING_CALL > > The patch set resolves both of these issues. > > Test case: > > 1. Start fio process (inside VM): > fio --name test --ioengine=libaio --iodepth=64 --bs=4096 \ > --rw=randrw --direct=1 --sync=1 --verify=md5 \ > --size=64M --filename=/dev/vda --loops=100 > > 2. Restart SPDK many times. > We are expecting that during SPDK restart fio will pause and fio should > continue to work after restart completion. > > 3. fio process completed successfully without any error.
Can you write a test case in vhost-user-test.c ? (perhaps under QTEST_VHOST_USER_FIXME scope...) > > Yury Kotov (3): > chardev: prevent extra connection attempt in tcp_chr_machine_done_hook > vhost: refactor vhost_dev_start and vhost_virtqueue_start > vhost-user: add reconnect support for vhost-user > > chardev/char-socket.c | 5 +- > hw/virtio/vhost-user.c | 65 ++++++++++++-- > hw/virtio/vhost.c | 223 > +++++++++++++++++++++++++++++++--------------- > include/hw/virtio/vhost.h | 2 + > 4 files changed, 215 insertions(+), 80 deletions(-) > > -- > 2.7.4 >
