[Qemu-devel] [PATCH v4 0/5] handle vhost reset/start/stop correctly

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

Patch 1 rename RESET_DEVICE back to RESET_OWNER

Patch 2 introduced a new function: vhost_net_reset(), which is invoked
        when reset happens, say, driver is unloaded (unbinded).

        Michael suggested to do that only when MQ is not negotiated.
        However, reset happens no matter MQ is enabled or negotiated
        or not, and we should give a sign to backend to reset some
        device to a proper state after it happens.

        Note that the message sent is still RESET_OWNER. It might not
        be a good idea, but we could not simply rename it to RESET_DEVICE,
        and maybe adding another RESET_DEVICE might be better.

Patch 3 and 4 send SET_PROTOCOL_FEATURES at start, just like we send
        SET_FEATURES.

Patch 5 send SET_VRING_ENABLE at start/stop

        Michael, I intended to send it when MQ is negotiated as you suggested,
        however, I found that VHOST_USER_PROTOCOL_F_MQ is defined in vhost-user.c,
        which is not accessible to vhost.c.

        Exporting it to vhost.h will resolve that, however, it's not a good
        idea to move vhost user specific stuff to there. We could also introduce
        another vhost callback to test whether MQ is negotiated: I just don't
        think it's worthy.

        Hence, here I just used a simple test: invoke set_vring_enable() just
        when it is defined. Judging the callback self has another MQ check,
        I guess it's okay.

And sorry that it took so long to send this version.

---
Yuanhan Liu (5):
  vhost: rename RESET_DEVICE backto RESET_OWNER
  vhost: reset vhost net when virtio_net_reset happens
  vhost: introduce vhost_set/get_protocol_features callbacks
  vhost: send SET_PROTOCOL_FEATURES at start
  vhost: send SET_VRING_ENABLE at start/stop

 docs/specs/vhost-user.txt         |  4 ++--
 hw/net/vhost_net.c                | 20 ++++++++++++++------
 hw/net/virtio-net.c               | 14 ++++++++++++++
 hw/virtio/vhost-backend.c         |  2 +-
 hw/virtio/vhost-user.c            | 13 ++++++++++---
 hw/virtio/vhost.c                 | 17 +++++++++++++++++
 include/hw/virtio/vhost-backend.h |  6 ++++++
 include/net/vhost_net.h           |  1 +
 linux-headers/linux/vhost.h       |  2 +-
 tests/vhost-user-bridge.c         |  6 +++---
 tests/vhost-user-test.c           |  4 ++--
 11 files changed, 71 insertions(+), 18 deletions(-)

-- 
1.9.0