[dpdk-dev] [PATCH] doc: update the doc for adding EAL option

[eric zhang <eric.zhang@windriver.com>]

This patch updates Programmer's Guide and EAL parameter guides
to show EAL option "--iova-mode" support.

Signed-off-by: eric zhang <eric.zhang@windriver.com>
---
 doc/guides/prog_guide/env_abstraction_layer.rst | 8 ++++++++
 doc/guides/testpmd_app_ug/run_app.rst           | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/doc/guides/prog_guide/env_abstraction_layer.rst b/doc/guides/prog_guide/env_abstraction_layer.rst
index d362c92..a47fb38 100644
--- a/doc/guides/prog_guide/env_abstraction_layer.rst
+++ b/doc/guides/prog_guide/env_abstraction_layer.rst
@@ -321,6 +321,14 @@ Misc Functions
 
 Locks and atomic operations are per-architecture (i686 and x86_64).
 
+IOVA Mode Configuration
+~~~~~~~~~~~~~~~~~~~~~~~
+
+Auto detection of the IOVA mode, based on probing the PCI bus and IOMMU configuration, may not report
+the desired addressing mode when virtual devices that are not directly attached to the PCI bus are present.
+To facilitate forcing the IOVA mode to a specific value the EAL command line option ``--iova-mode=mode`` can
+be used to select either physical addressing('pa') or virtual addressing('va').
+
 Memory Segments and Memory Zones (memzone)
 ------------------------------------------
 
diff --git a/doc/guides/testpmd_app_ug/run_app.rst b/doc/guides/testpmd_app_ug/run_app.rst
index f301c2b..be2911c 100644
--- a/doc/guides/testpmd_app_ug/run_app.rst
+++ b/doc/guides/testpmd_app_ug/run_app.rst
@@ -133,6 +133,10 @@ See the DPDK Getting Started Guides for more information on these options.
 
     Use malloc instead of hugetlbfs.
 
+*   ``--iova-mode=mode``
+
+    Force IOVA mode to a specific value. Valid values are 'pa' or 'va'.
+
 
 Testpmd Command-line Options
 ----------------------------
-- 
2.7.4