Hi On Mon, Aug 20, 2018 at 2:51 PM, Yury Kotov <yury-ko...@yandex-team.ru> wrote: > 16.08.2018, 18:36, "Marc-André Lureau" <marcandre.lur...@redhat.com>: >> 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...) >> > > This is a great idea and we were definitely going to do that during coming > couple of weeks. We thought that we could make a follow up commit with > necessary tests added a bit later though, since currently we need to figure > out the state of vhost-user tests in general, before we can try to add any > new stuff, and that will take some time. So far we have stress-tested these > fixes manually.
Yes, some vhost-user tests are disabled by default (sadly for travis CI reason - not a really bug), and it's easy to introduce regressions. I sent a related series "[PATCH 0/4] Fix socket chardev regression" to make it work again. > Do you suggest we wait with this series as well until we have all tests > ready? Or do we proceed now and make a follow up series with vhost user tests > later like we suggested? I would rather have the tests with the series. > >>> 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
