[PATCH 0/9] vhost-user: Migration support

[Laurent Vivier <lvivier@redhat.com>]

This series allows a QEMU guest to be migrated while it is connected
to Passt using vhost-user interface.

There are two parts:

- first part enables the migration of QEMU without transferring the
  internal state of Passt. All connections are lost.

  This is done by implementing VHOST_USER_SET_LOG_FD and
  VHOST_USER_SET_LOG_BASE commands (and enabling
  VHOST_USER_PROTOCOL_F_LOG_SHMFD feature)

  "vhost-user: add VHOST_USER_SET_LOG_FD command"
  "vhost-user: add VHOST_USER_SET_LOG_BASE command"
  "vhost-user: Report to front-end we support VHOST_USER_PROTOCOL_F_LOG_SHMFD"

- second part allows source Passt instance to send its internal
  state using QEMU migration channel to destination Passt instance.

  This is done implementing VHOST_USER_SET_DEVICE_STATE_FD and
  VHOST_USER_CHECK_DEVICE_STATE (and enabling
  VHOST_USER_PROTOCOL_F_DEVICE_STATE feature).

  "vhost-user: add VHOST_USER_CHECK_DEVICE_STATE command"
  "vhost-user: add VHOST_USER_SET_DEVICE_STATE_FD command"
  "vhost-user: Report to front-end we support VHOST_USER_PROTOCOL_F_DEVICE_STATE"

  For now, it only implements the function needed to transfer the
  state but no state is transferred.

  VHOST_USER_PROTOCOL_F_DEVICE_STATE is implemented in QEMU
  only for vhost-user-fs, to be able to use it with virtio-net
  I have proposed a patch upstream:

  https://patchew.org/QEMU/20241218143453.1573185-1-lvivier@redhat.com/

Laurent Vivier (9):
  virtio: Use const pointer for vu_dev
  vhost-user: update protocol features and commands list
  vhost-user: add VHOST_USER_SET_LOG_FD command
  vhost-user: Pass vu_dev to more virtio functions
  vhost-user: add VHOST_USER_SET_LOG_BASE command
  vhost-user: Report to front-end we support
    VHOST_USER_PROTOCOL_F_LOG_SHMFD
  vhost-user: add VHOST_USER_CHECK_DEVICE_STATE command
  vhost-user: add VHOST_USER_SET_DEVICE_STATE_FD command
  vhost-user: Report to front-end we support
    VHOST_USER_PROTOCOL_F_DEVICE_STATE

 epoll_type.h |   2 +
 passt.c      |   4 +
 util.h       |   3 +
 vhost_user.c | 251 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 vhost_user.h |  50 +++++++++-
 virtio.c     | 116 +++++++++++++++++++++---
 virtio.h     |  32 +++++--
 vu_common.c  |  59 +++++++++++-
 vu_common.h  |   3 +-
 9 files changed, 484 insertions(+), 36 deletions(-)

-- 
2.47.1