diff options
Diffstat (limited to 'docs/interop')
| -rw-r--r-- | docs/interop/vhost-user.rst | 44 |
1 files changed, 31 insertions, 13 deletions
diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst index ae8c7ed995..c1e02ff7e9 100644 --- a/docs/interop/vhost-user.rst +++ b/docs/interop/vhost-user.rst @@ -457,6 +457,7 @@ replies, except for the following requests: * ``VHOST_USER_GET_FEATURES`` * ``VHOST_USER_GET_PROTOCOL_FEATURES`` * ``VHOST_USER_GET_VRING_BASE`` +* ``VHOST_USER_GET_VRING_BASE_SKIP_DRAIN`` * ``VHOST_USER_SET_LOG_BASE`` (if ``VHOST_USER_PROTOCOL_F_LOG_SHMFD``) * ``VHOST_USER_GET_INFLIGHT_FD`` (if ``VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD``) @@ -533,7 +534,7 @@ Rings have two independent states: started/stopped, and enabled/disabled. Each ring is initialized in a stopped and disabled state. Rings are started with ``VHOST_USER_SET_VRING_KICK`` (or ``VHOST_USER_VRING_KICK`` if ``VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS`` is negotiated) and stopped with -``VHOST_USER_GET_VRING_BASE``. A stopped ring enters the started state again +``VHOST_USER_GET_VRING_BASE`` or ``VHOST_USER_GET_VRING_BASE_SKIP_DRAIN``. A stopped ring enters the started state again with ``VHOST_USER_SET_VRING_KICK`` (or ``VHOST_USER_VRING_KICK`` if ``VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS`` is negotiated) and the back-end resumes processing requests. @@ -1158,7 +1159,8 @@ Protocol features #define VHOST_USER_PROTOCOL_F_DEVICE_STATE 19 #define VHOST_USER_PROTOCOL_F_GET_VRING_BASE_INFLIGHT 20 #define VHOST_USER_PROTOCOL_F_GPA_ADDRESSES 21 - #define VHOST_USER_PROTOCOL_F_SHMEM_MAP 22 + #define VHOST_USER_PROTOCOL_F_SHMEM 22 + #define VHOST_USER_PROTOCOL_F_GET_VRING_BASE_SKIP_DRAIN 23 Front-end message types ----------------------- @@ -1355,17 +1357,11 @@ Front-end message types set to 0. By default, the back-end must complete all inflight I/O requests for the - specified vring before stopping it. - - If the ``VHOST_USER_PROTOCOL_F_GET_VRING_BASE_INFLIGHT`` protocol - feature has been negotiated, the back-end may suspend in-flight I/O - requests and record them as described in :ref:`Inflight I/O tracking - <inflight_io_tracking>` instead of completing them before stopping the vring. - How to suspend an in-flight request depends on the implementation of the back-end - but it typically can be done by aborting or cancelling the underlying I/O - request. The ``VHOST_USER_PROTOCOL_F_GET_VRING_BASE_INFLIGHT`` - protocol feature must only be negotiated if - ``VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD`` is also negotiated. + specified vring before stopping it. If the + ``VHOST_USER_PROTOCOL_F_GET_VRING_BASE_SKIP_DRAIN`` protocol feature has + been negotiated, the front-end may instead use + ``VHOST_USER_GET_VRING_BASE_SKIP_DRAIN`` to request the back-end to + suspend in-flight I/O immediately. ``VHOST_USER_SET_VRING_KICK`` :id: 12 @@ -1868,6 +1864,28 @@ Front-end message types * The size may be 0 if the region is unused. +``VHOST_USER_GET_VRING_BASE_SKIP_DRAIN`` + :id: 45 + :equivalent ioctl: N/A + :request payload: vring state description + :reply payload: vring descriptor index/indices + + This message requires the ``VHOST_USER_PROTOCOL_F_GET_VRING_BASE_SKIP_DRAIN`` + protocol feature to be negotiated. + + Identical to ``VHOST_USER_GET_VRING_BASE`` except that the back-end + must not wait for inflight I/O requests to complete before stopping + the vring. Instead, the back-end must immediately suspend all + in-flight I/O requests and record them as described in + :ref:`Inflight I/O tracking <inflight_io_tracking>`. How to suspend + an in-flight request depends on the implementation of the back-end, + but it typically can be done by aborting or cancelling the underlying + I/O request. + + The ``VHOST_USER_PROTOCOL_F_GET_VRING_BASE_SKIP_DRAIN`` protocol feature + must only be negotiated if both ``VHOST_USER_PROTOCOL_F_GET_VRING_BASE_INFLIGHT`` + and ``VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD`` are also negotiated. + Back-end message types ---------------------- |