gve: update gve.rst

Add a note about QPL and RDA mode
Signed-off-by: Rushil Gupta <rushilg@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Praveen Kaligineedi <pkaligineedi@google.com>
Signed-off-by: Bailey Forrest <bcf@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/device_drivers/ethernet/google/gve.rst

@@ -52,6 +52,15 @@ Descriptor Formats
 GVE supports two descriptor formats: GQI and DQO. These two formats have
 entirely different descriptors, which will be described below.
 
+Addressing Mode
+------------------
+GVE supports two addressing modes: QPL and RDA.
+QPL ("queue-page-list") mode communicates data through a set of
+pre-registered pages.
+
+For RDA ("raw DMA addressing") mode, the set of pages is dynamic.
+Therefore, the packet buffers can be anywhere in guest memory.
+
 Registers
 ---------
 All registers are MMIO.