On Tue, Aug 04, 2020 at 01:36:45PM +0300, Dima Stepanov wrote: > Reference e-mail threads: > - https://lists.gnu.org/archive/html/qemu-devel/2020-05/msg01509.html > - https://lists.gnu.org/archive/html/qemu-devel/2020-05/msg05241.html > > If vhost-user daemon is used as a backend for the vhost device, then we > should consider a possibility of disconnect at any moment. There was a general > question here: should we consider it as an error or okay state for the > vhost-user > devices during migration process? > I think the disconnect event for the vhost-user devices 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 > The first patch in the patchset fixes this issue by setting vhost device to > the > stopped state in the disconnect handler and check it the vhost_migration_log() > routine before returning from the function. > qtest framework was updated to test vhost-user-blk functionality. The > vhost-user-blk/vhost-user-blk-tests/migrate_reconnect test was added to > reproduce > the original issue found.
Raphael any input on this? > Dima Stepanov (7): > vhost: recheck dev state in the vhost_migration_log routine > vhost: check queue state in the vhost_dev_set_log routine > tests/qtest/vhost-user-test: prepare the tests for adding new dev > class > tests/qtest/libqos/virtio-blk: add support for vhost-user-blk > tests/qtest/vhost-user-test: add support for the vhost-user-blk device > tests/qtest/vhost-user-test: add migrate_reconnect test > tests/qtest/vhost-user-test: enable the reconnect tests > > hw/block/vhost-user-blk.c | 13 +- > hw/virtio/vhost.c | 39 ++++- > include/hw/virtio/vhost-user-blk.h | 1 + > tests/qtest/libqos/virtio-blk.c | 14 ++ > tests/qtest/vhost-user-test.c | 291 > +++++++++++++++++++++++++++++++------ > 5 files changed, 311 insertions(+), 47 deletions(-) > > -- > 2.7.4