docs/interop/vhost-user.rst

47 - A way for requesting shared memory represented by a file descriptor
56   resort, pipe. Each file descriptor will be used for receiving or
111 A vring descriptor index for split virtqueues
123   - Bits 0–15: Index of the next *Available Ring* descriptor that the
128 Vring descriptor indices for packed virtqueues
132 | vring index | descriptor indices |
137 :descriptor indices: 32-bit value:
139   - Bits 0–14: Index of the next *Available Ring* descriptor that the
144     will place the next descriptor.  This is a free-running index that
152 | index | flags | descriptor | used | available | log |
159 :descriptor: a 64-bit ring address of the vring descriptor table
240 :log offset: a 64-bit offset from start of supplied file descriptor where
299          supplied file descriptor
311               of the supplied file descriptor
460 descriptor is readable) on the descriptor specified by
535 All the modifications to memory pointed by vring "descriptor" should
549 at the supplied offset in the supplied file descriptor.  The log
745 descriptor table (split virtqueue) or descriptor ring (packed
748 inflight descriptors in available ring (split virtqueue) or descriptor
769       /* Indicate whether this descriptor is inflight or not.
770        * Only available for head-descriptor. */
781        * Only available for head-descriptor. */
803       /* Used to track the state of each descriptor in descriptor table */
811 #. Get the next available head-descriptor index from available ring, ``i``
821 1. Get corresponding used head-descriptor index, i
857       /* Indicate whether this descriptor is inflight or not.
858        * Only available for head-descriptor. */
867       /* Link to the last entry of descriptor list.
868        * Only available for head-descriptor. */
871       /* The length of descriptor list.
872        * Only available for head-descriptor. */
876        * Only available for head-descriptor. */
882       /* The descriptor flags */
910       /* The used index of descriptor ring */
913       /* The old used index of descriptor ring */
925       /* Used to track the state of each descriptor fetched from descriptor ring */
933 #. Get the next available descriptor entry from descriptor ring, ``d``
935 #. If ``d`` is head descriptor,
945 #. If ``d`` is last descriptor, set ``desc[old_free_head].last`` to
956 #. If ``d`` is last descriptor, set ``old_free_head`` to ``free_head``
960 1. Get corresponding used head-descriptor entry from descriptor ring,
988    a. Get the next descriptor ring entry through ``old_used_idx``, ``d``
1181   Sets the logging file descriptor, which is passed as ancillary data.
1202   :request payload: vring descriptor index/indices
1207   * For a split virtqueue, sets only the next descriptor index to
1216   (*a vring descriptor index for split virtqueues* vs. *vring descriptor
1223   :reply payload: vring descriptor index/indices
1225   Stops the vring and returns the current descriptor index or indices:
1227     * For a split virtqueue, returns only the 16-bit next descriptor
1232       descriptor index at which to put new descriptors, which is the
1241   (*a vring descriptor index for split virtqueues* vs. *vring descriptor
1257   Set the event file descriptor for adding buffers to the vring. It is
1261   invalid FD flag. This flag is set when there is no file descriptor
1267   set an event file descriptor (which will be preferred over the
1276   Set the event file descriptor to signal when buffers are used. It is
1280   invalid FD flag. This flag is set when there is no file descriptor
1286   used, it may however still be used to set an event file descriptor
1295   Set the event file descriptor to signal when error occurs. It is
1299   invalid FD flag. This flag is set when there is no file descriptor
1304   used, it may however still be used to set an event file descriptor
1370   Set the socket file descriptor for back-end initiated requests. It is passed
1531   Sets the GPU protocol socket file descriptor, which is passed as
1559   descriptor or having the back-end rely on polling.
1586   region descriptor struct, describing a region of guest memory which
1593   Exactly one file descriptor from which the memory is mapped is
1610   region descriptor struct, describing a region of guest memory which
1622   accept messages with one file descriptor. If a file descriptor is
1670   must create a file descriptor that is provided to the respectively
1675     sequentially.  Closing the file descriptor signals the end of
1703   file descriptor for a back-end-provided channel is returned: Bits 0–7
1705   flag; this flag is set when there is no file descriptor returned.
1707   descriptor as its end of the transfer channel.  The back-end must not
1708   both indicate an error and return a file descriptor.
1774   host notifier is described by the file descriptor (typically it's a
1778   description. QEMU can mmap the file descriptor based on the size and
1783   request is sent with a file descriptor.
1799   descriptor or having the front-end relying on polling.
1812   specific vring, instead of signalling the error file descriptor
1937   vhost-user socket as file descriptor FDNUM. It is incompatible with