vhost: introduce driver features related APIs

Introduce few APIs to set/get/enable/disable driver features.

Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

diff --git a/doc/guides/prog_guide/vhost_lib.rst b/doc/guides/prog_guide/vhost_lib.rst
index f0862e6..6a4d206 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
 ------------------
 
-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)``
 
@@ -110,6 +110,12 @@ 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.
 
+* ``rte_vhost_driver_set_features(path, features)``
+
+  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_session_start()``
 
   This function starts the vhost session loop to handle vhost messages. It
@@ -145,7 +151,7 @@ The following is an overview of the Vhost API functions:
 
   Receives (dequeues) ``count`` packets from guest, and stored them at ``pkts``.
 
-* ``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

diff --git a/lib/librte_vhost/rte_vhost_version.map b/lib/librte_vhost/rte_vhost_version.map
index 30b4671..ca6259c 100644 (file)
--- a/lib/librte_vhost/rte_vhost_version.map
+++ b/lib/librte_vhost/rte_vhost_version.map
@@ -34,6 +34,10 @@ DPDK_16.07 {
 DPDK_17.05 {
        global:
 
+       rte_vhost_driver_disable_features;
+       rte_vhost_driver_enable_features;
+       rte_vhost_driver_get_features;
+       rte_vhost_driver_set_features;
        rte_vhost_get_mtu;
 
 } DPDK_16.07;

diff --git a/lib/librte_vhost/rte_virtio_net.h b/lib/librte_vhost/rte_virtio_net.h
index 56829aa..7bb8af6 100644 (file)
--- a/lib/librte_vhost/rte_virtio_net.h
+++ b/lib/librte_vhost/rte_virtio_net.h
@@ -94,6 +94,61 @@ int rte_vhost_driver_register(const char *path, uint64_t flags);
 /* Unregister vhost driver. This is only meaningful to vhost user. */
 int rte_vhost_driver_unregister(const char *path);
 
+/**
+ * Set the feature bits the vhost-user driver supports.
+ *
+ * @param path
+ *  The vhost-user socket file path
+ * @param features
+ *  Supported features
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vhost_driver_set_features(const char *path, uint64_t features);
+
+/**
+ * Enable vhost-user driver features.
+ *
+ * Note that
+ * - the param features should be a subset of the feature bits provided
+ *   by rte_vhost_driver_set_features().
+ * - it must be invoked before vhost-user negotiation starts.
+ *
+ * @param path
+ *  The vhost-user socket file path
+ * @param features
+ *  Features to enable
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vhost_driver_enable_features(const char *path, uint64_t features);
+
+/**
+ * Disable vhost-user driver features.
+ *
+ * The two notes at rte_vhost_driver_enable_features() also apply here.
+ *
+ * @param path
+ *  The vhost-user socket file path
+ * @param features
+ *  Features to disable
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vhost_driver_disable_features(const char *path, uint64_t features);
+
+/**
+ * Get the feature bits before feature negotiation.
+ *
+ * @param path
+ *  The vhost-user socket file path
+ * @param features
+ *  A pointer to store the queried feature bits
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vhost_driver_get_features(const char *path, uint64_t *features);
+
 /* Register callbacks. */
 int rte_vhost_driver_callback_register(struct virtio_net_device_ops const * const);
 /* Start vhost driver session blocking loop. */

diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
index 2afde98..53663f4 100644 (file)
--- a/lib/librte_vhost/socket.c
+++ b/lib/librte_vhost/socket.c
@@ -67,6 +67,16 @@ struct vhost_user_socket {
        bool is_server;
        bool reconnect;
        bool dequeue_zero_copy;
+
+       /*
+        * The "supported_features" indicates the feature bits the
+        * vhost driver supports. The "features" indicates the feature
+        * bits after the rte_vhost_driver_features_disable/enable().
+        * It is also the final feature bits used for vhost-user
+        * features negotiation.
+        */
+       uint64_t supported_features;
+       uint64_t features;
 };
 
 struct vhost_user_connection {
@@ -490,6 +500,88 @@ vhost_user_create_client(struct vhost_user_socket *vsocket)
        return 0;
 }
 
+static struct vhost_user_socket *
+find_vhost_user_socket(const char *path)
+{
+       int i;
+
+       for (i = 0; i < vhost_user.vsocket_cnt; i++) {
+               struct vhost_user_socket *vsocket = vhost_user.vsockets[i];
+
+               if (!strcmp(vsocket->path, path))
+                       return vsocket;
+       }
+
+       return NULL;
+}
+
+int
+rte_vhost_driver_disable_features(const char *path, uint64_t features)
+{
+       struct vhost_user_socket *vsocket;
+
+       pthread_mutex_lock(&vhost_user.mutex);
+       vsocket = find_vhost_user_socket(path);
+       if (vsocket)
+               vsocket->features &= ~features;
+       pthread_mutex_unlock(&vhost_user.mutex);
+
+       return vsocket ? 0 : -1;
+}
+
+int
+rte_vhost_driver_enable_features(const char *path, uint64_t features)
+{
+       struct vhost_user_socket *vsocket;
+
+       pthread_mutex_lock(&vhost_user.mutex);
+       vsocket = find_vhost_user_socket(path);
+       if (vsocket) {
+               if ((vsocket->supported_features & features) != features) {
+                       /*
+                        * trying to enable features the driver doesn't
+                        * support.
+                        */
+                       pthread_mutex_unlock(&vhost_user.mutex);
+                       return -1;
+               }
+               vsocket->features |= features;
+       }
+       pthread_mutex_unlock(&vhost_user.mutex);
+
+       return vsocket ? 0 : -1;
+}
+
+int
+rte_vhost_driver_set_features(const char *path, uint64_t features)
+{
+       struct vhost_user_socket *vsocket;
+
+       pthread_mutex_lock(&vhost_user.mutex);
+       vsocket = find_vhost_user_socket(path);
+       if (vsocket) {
+               vsocket->supported_features = features;
+               vsocket->features = features;
+       }
+       pthread_mutex_unlock(&vhost_user.mutex);
+
+       return vsocket ? 0 : -1;
+}
+
+int
+rte_vhost_driver_get_features(const char *path, uint64_t *features)
+{
+       struct vhost_user_socket *vsocket;
+
+       pthread_mutex_lock(&vhost_user.mutex);
+       vsocket = find_vhost_user_socket(path);
+       if (vsocket)
+               *features = vsocket->features;
+       pthread_mutex_unlock(&vhost_user.mutex);
+
+       return vsocket ? 0 : -1;
+}
+
 /*
  * Register a new vhost-user socket; here we could act as server
  * (the default case), or client (when RTE_VHOST_USER_CLIENT) flag