[PATCH 10/10] doc: update nfp document

[Chaoyong He <chaoyong.he@corigine.com>]

From: Xinying Yu <xinying.yu@corigine.com>

Add the software assisted vDPA live migration feature
into NFP document.

Signed-off-by: Xinying Yu <xinying.yu@corigine.com>
Reviewed-by: Chaoyong He <chaoyong.he@corigine.com>
Reviewed-by: Long Wu <long.wu@corigine.com>
Reviewed-by: Peng Zhang <peng.zhang@corigine.com>
---
 doc/guides/vdpadevs/nfp.rst | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/doc/guides/vdpadevs/nfp.rst b/doc/guides/vdpadevs/nfp.rst
index dc9e94dbc8..e4736d9f61 100644
--- a/doc/guides/vdpadevs/nfp.rst
+++ b/doc/guides/vdpadevs/nfp.rst
@@ -19,6 +19,15 @@ device will be probed by net/nfp driver and will used as a VF net device.
 
 This PMD uses (common/nfp) code to access the device firmware.
 
+Software Live Migration
+~~~~~~~~~~~~~~~~~~~~~~~
+
+Now the NFP vDPA driver only support software assisted live migration mode.
+In this mode, the driver will setup a software relay thread when live migration
+happens, this thread will help device to log dirty pages. Although this mode
+does not require hardware to implement a dirty page logging function block, it
+will consume percentage of CPU resource depending on the network throughput.
+
 Per-Device Parameters
 ~~~~~~~~~~~~~~~~~~~~~
 
-- 
2.39.1