+ - ``RTE_VHOST_USER_EXTBUF_SUPPORT``
+
+ Enabling this flag allows vhost dequeue function to allocate and attach
+ an external buffer to a pktmbuf if the pkmbuf doesn't provide enough
+ space to store all data.
+
+ This is useful when the vhost application wants to support large packets
+ but doesn't want to increase the default mempool object size nor to
+ support multi-segmented mbufs (non-linear). In this case, a fresh buffer
+ is allocated using rte_malloc() which gets attached to a pktmbuf using
+ rte_pktmbuf_attach_extbuf().
+
+ See RTE_VHOST_USER_LINEARBUF_SUPPORT as well to disable multi-segmented
+ mbufs for application that doesn't support chained mbufs.
+
+ It is disabled by default.
+
+ - ``RTE_VHOST_USER_ASYNC_COPY``
+
+ Asynchronous data path will be enabled when this flag is set. Async data
+ path allows applications to register async copy devices (typically
+ hardware DMA channels) to the vhost queues. Vhost leverages the copy
+ device registered to free CPU from memory copy operations. A set of
+ async data path APIs are defined for DPDK applications to make use of
+ the async capability. Only packets enqueued/dequeued by async APIs are
+ processed through the async data path.
+
+ Currently this feature is only implemented on split ring enqueue data
+ path.
+
+ It is disabled by default.
+
+ - ``RTE_VHOST_USER_NET_COMPLIANT_OL_FLAGS``
+
+ Since v16.04, the vhost library forwards checksum and gso requests for
+ packets received from a virtio driver by filling Tx offload metadata in
+ the mbuf. This behavior is inconsistent with other drivers but it is left
+ untouched for existing applications that might rely on it.
+
+ This flag disables the legacy behavior and instead ask vhost to simply
+ populate Rx offload metadata in the mbuf.
+
+ It is disabled by default.
+
+* ``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_callback_register(path, vhost_device_ops)``