.. _`UUID`: https://en.wikipedia.org/wiki/Universally_unique_identifier
-There are several possible ways to assign the uio device driver for a device.
+There are several possible ways to assign the UIO device driver for a device.
The easiest way (but only on 4.18 or later)
is to use the `driverctl Device Driver control utility`_ to override
the normal kernel device.
set larger than the MTU, then all packets smaller than the chunk size
of the VMBus send buffer will be copied; larger packets always have to
go as a single direct request. The default value is 512 (bytes).
+
+#. ``rx_extmbuf_enable``:
+ The rx_extmbuf_enable is used to control if netvsc should use external
+ mbuf for receiving packets. The default value is 0. (netvsc doesn't use
+ external mbuf, it always allocates mbuf and copy received data to mbuf)
+ A non-zero value tells netvsc to attach external buffers to mbuf on
+ receiving packets, thus avoid copying memory. Use of external buffers
+ requires the application is able to read data from external mbuf.