v1 -> v2:
  - add comments to connected/started fields in the header file
  - move the "s->started" logic from the vhost_user_blk_disconnect
    routine to the vhost_user_blk_stop routine

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.

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          |  19 ++-
 hw/virtio/vhost.c                  |  39 ++++-
 include/hw/virtio/vhost-user-blk.h |  10 ++
 tests/qtest/libqos/virtio-blk.c    |  14 ++
 tests/qtest/vhost-user-test.c      | 291 +++++++++++++++++++++++++++++++------
 5 files changed, 324 insertions(+), 49 deletions(-)

-- 
2.7.4

Patchew URL: https://patchew.org/QEMU/cover.1598257838.git.dimastep@yandex-team.ru/



Hi,

This series failed the docker-quick@centos7 build test. Please find the testing commands and
their output below. If you have Docker installed, you can probably reproduce it
locally.

=== TEST SCRIPT BEGIN ===
#!/bin/bash
make docker-image-centos7 V=1 NETWORK=1
time make docker-test-quick@centos7 SHOW_ENV=1 J=14 NETWORK=1
=== TEST SCRIPT END ===

C linker for the host machine: cc ld.bfd 2.27-43
Host machine cpu family: x86_64
Host machine cpu: x86_64
../src/meson.build:9: WARNING: Module unstable-keyval has no backwards or forwards compatibility and might not exist in future releases.
Program sh found: YES
Program python3 found: YES (/usr/bin/python3)
C++ compiler for the host machine: c++ (gcc 4.8.5 "c++ (GCC) 4.8.5 20150623 (Red Hat 4.8.5-39)")
---
             Linux keyring: YES

Found ninjatool-1.8 at /tmp/qemu-test/build/ninjatool
WARNING: custom_target 'shared QAPI source files' has more than one output! Using the first one.
WARNING: custom_target 'QGA QAPI files' has more than one output! Using the first one.
WARNING: custom_target 'QAPI files for qemu-storage-daemon' has more than one output! Using the first one.
WARNING: custom_target 'QAPI doc' has more than one output! Using the first one.
WARNING: custom_target 'dbus-vmstate description' has more than one output! Using the first one.
Command line for building ['libcommon.fa'] is long, using a response file
Command line for building ['libqemu-aarch64-softmmu.fa'] is long, using a response file
Command line for building ['qemu-system-aarch64'] is long, using a response file
---
Linking static target hw/core/libhwcore.fa
Linking static target chardev/libchardev.fa
../src/tests/qtest/vhost-user-test.c: In function 'test_reconnect':
../src/tests/qtest/vhost-user-test.c:935:9: error: 'nq' may be used uninitialized in this function [-Werror=maybe-uninitialized]
     int nq;
         ^
cc1: all warnings being treated as errors
make: *** [tests/qtest/qos-test.p/vhost-user-test.c.o] Error 1
make: *** Waiting for unfinished jobs....
Traceback (most recent call last):
  File "./tests/docker/docker.py", line 709, in <module>
---
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['sudo', '-n', 'docker', 'run', '--label', 'com.qemu.instance.uuid=b3addb190ca74c36acdbb7205792264a', '-u', '1001', '--security-opt', 'seccomp=unconfined', '--rm', '-e', 'TARGET_LIST=', '-e', 'EXTRA_CONFIGURE_OPTS=', '-e', 'V=', '-e', 'J=14', '-e', 'DEBUG=', '-e', 'SHOW_ENV=1', '-e', 'CCACHE_DIR=/var/tmp/ccache', '-v', '/home/patchew/.cache/qemu-docker-ccache:/var/tmp/ccache:z', '-v', '/var/tmp/patchew-tester-tmp-b6ixlpeu/src/docker-src.2020-08-24-09.41.48.11658:/var/tmp/qemu:z,ro', 'qemu/centos7', '/var/tmp/qemu/run', 'test-quick']' returned non-zero exit status 2.
filter=--filter=label=com.qemu.instance.uuid=b3addb190ca74c36acdbb7205792264a
make[1]: *** [docker-run] Error 1
make[1]: Leaving directory `/var/tmp/patchew-tester-tmp-b6ixlpeu/src'
make: *** [docker-run-test-quick@centos7] Error 2

real    4m29.821s
user    0m21.159s


The full log is available at
http://patchew.org/logs/cover.1598257838.git.dimastep@yandex-team.ru/testing.docker-quick@centos7/?type=message.
---
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