Imported Upstream version 17.05

[deb_dpdk.git] / doc / guides / prog_guide / vhost_lib.rst

diff --git a/doc/guides/prog_guide/vhost_lib.rst b/doc/guides/prog_guide/vhost_lib.rst
index 4f997d4..5979290 100644 (file)
--- a/doc/guides/prog_guide/vhost_lib.rst
+++ b/doc/guides/prog_guide/vhost_lib.rst
@@ -53,7 +53,7 @@ vhost library should be able to:
 Vhost API Overview
 ------------------
 
 Vhost API Overview
 ------------------
 

-The following is an overview of the Vhost API functions:
+The following is an overview of some key Vhost API functions:

 
 * ``rte_vhost_driver_register(path, flags)``
 
 
 * ``rte_vhost_driver_register(path, flags)``
 


@@ -95,7 +95,7 @@ The following is an overview of the Vhost API functions:
     * for VM2NIC case, the ``nb_tx_desc`` has to be small enough: <= 64 if virtio
       indirect feature is not enabled and <= 128 if it is enabled.
 
     * for VM2NIC case, the ``nb_tx_desc`` has to be small enough: <= 64 if virtio
       indirect feature is not enabled and <= 128 if it is enabled.
 

-      The is because when dequeue zero copy is enabled, guest Tx used vring will
+      This is because when dequeue zero copy is enabled, guest Tx used vring will

       be updated only when corresponding mbuf is freed. Thus, the nb_tx_desc
       has to be small enough so that the PMD driver will run out of available
       Tx descriptors and free mbufs timely. Otherwise, guest Tx vring would be
       be updated only when corresponding mbuf is freed. Thus, the nb_tx_desc
       has to be small enough so that the PMD driver will run out of available
       Tx descriptors and free mbufs timely. Otherwise, guest Tx vring would be


@@ -110,13 +110,13 @@ The following is an overview of the Vhost API functions:
       of those segments, thus the fewer the segments, the quicker we will get
       the mapping. NOTE: we may speed it by using tree searching in future.
 
       of those segments, thus the fewer the segments, the quicker we will get
       the mapping. NOTE: we may speed it by using tree searching in future.
 

-* ``rte_vhost_driver_session_start()``
+* ``rte_vhost_driver_set_features(path, features)``

 
 

-  This function starts the vhost session loop to handle vhost messages. It
-  starts an infinite loop, therefore it should be called in a dedicated
-  thread.
+  This function sets the feature bits the vhost-user driver supports. The
+  vhost-user driver could be vhost-user net, yet it could be something else,
+  say, vhost-user SCSI.

 
 

-* ``rte_vhost_driver_callback_register(virtio_net_device_ops)``
+* ``rte_vhost_driver_callback_register(path, vhost_device_ops)``

 
   This function registers a set of callbacks, to let DPDK applications take
   the appropriate action when some events happen. The following events are
 
   This function registers a set of callbacks, to let DPDK applications take
   the appropriate action when some events happen. The following events are


@@ -124,12 +124,12 @@ The following is an overview of the Vhost API functions:
 
   * ``new_device(int vid)``
 
 
   * ``new_device(int vid)``
 

-    This callback is invoked when a virtio net device becomes ready. ``vid``
-    is the virtio net device ID.
+    This callback is invoked when a virtio device becomes ready. ``vid``
+    is the vhost device ID.

 
   * ``destroy_device(int vid)``
 
 
   * ``destroy_device(int vid)``
 

-    This callback is invoked when a virtio net device shuts down (or when the
+    This callback is invoked when a virtio device shuts down (or when the

     vhost connection is broken).
 
   * ``vring_state_changed(int vid, uint16_t queue_id, int enable)``
     vhost connection is broken).
 
   * ``vring_state_changed(int vid, uint16_t queue_id, int enable)``


@@ -137,20 +137,30 @@ The following is an overview of the Vhost API functions:
     This callback is invoked when a specific queue's state is changed, for
     example to enabled or disabled.
 
     This callback is invoked when a specific queue's state is changed, for
     example to enabled or disabled.
 

-* ``rte_vhost_enqueue_burst(vid, queue_id, pkts, count)``
-
-  Transmits (enqueues) ``count`` packets from host to guest.
-
-* ``rte_vhost_dequeue_burst(vid, queue_id, mbuf_pool, pkts, count)``
+  * ``features_changed(int vid, uint64_t features)``

 
 

-  Receives (dequeues) ``count`` packets from guest, and stored them at ``pkts``.
+    This callback is invoked when the features is changed. For example,
+    ``VHOST_F_LOG_ALL`` will be set/cleared at the start/end of live
+    migration, respectively.

 
 

-* ``rte_vhost_feature_disable/rte_vhost_feature_enable(feature_mask)``
+* ``rte_vhost_driver_disable/enable_features(path, features))``

 
   This function disables/enables some features. For example, it can be used to
   disable mergeable buffers and TSO features, which both are enabled by
   default.
 
 
   This function disables/enables some features. For example, it can be used to
   disable mergeable buffers and TSO features, which both are enabled by
   default.
 

+* ``rte_vhost_driver_start(path)``
+
+  This function triggers the vhost-user negotiation. It should be invoked at
+  the end of initializing a vhost-user driver.
+
+* ``rte_vhost_enqueue_burst(vid, queue_id, pkts, count)``
+
+  Transmits (enqueues) ``count`` packets from host to guest.
+
+* ``rte_vhost_dequeue_burst(vid, queue_id, mbuf_pool, pkts, count)``
+
+  Receives (dequeues) ``count`` packets from guest, and stored them at ``pkts``.

 
 Vhost-user Implementations
 --------------------------
 
 Vhost-user Implementations
 --------------------------