[PATCH] [PATCH 22.11] net/mlx5: fix modify field action operation restriction

[Maayan Kashani <mkashani@nvidia.com>]

Update DV flow engine modify field validation:
- Reject 'add' and 'sub' operations when source field is not VALUE
  or POINTER in DV flow engine.

Update documentation to clarify operation support:
- 'set' operation is supported in all modes
- 'add' operation with VALUE/POINTER source fields is
  supported in DV/HWS mode.
- Specify relevant HW supporting packet header as 'src' field.
- List supported 'dst' fields.

Fixes: 641dbe4fb053 ("net/mlx5: support modify field flow action")
Cc: stable@dpdk.org

Signed-off-by: Maayan Kashani <mkashani@nvidia.com>
Acked-by: Dariusz Sosnowski <dsosnowski@nvidia.com>
---
 .mailmap                        |  1 +
 doc/guides/nics/mlx5.rst        | 21 ++++++++++++++++++++-
 drivers/net/mlx5/mlx5_flow_dv.c |  7 +++++++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/.mailmap b/.mailmap
index f53fdf0d859..7cf02ea05a1 100644
--- a/.mailmap
+++ b/.mailmap
@@ -820,6 +820,7 @@ Luke Gorrie <luke@snabb.co>
 Lunyuan Cui <lunyuanx.cui@intel.com>
 Lu Qiuwen <luqiuwen@iie.ac.cn>
 Lyn M <netinal7@gmail.com>
+Maayan Kashani <mkashani@nvidia.com>
 Maciej Bielski <mba@semihalf.com>
 Maciej Czekaj <mczekaj@marvell.com> <maciej.czekaj@caviumnetworks.com>
 Maciej Fijalkowski <maciej.fijalkowski@intel.com>
diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst
index d2f741a4726..38006f5cc8d 100644
--- a/doc/guides/nics/mlx5.rst
+++ b/doc/guides/nics/mlx5.rst
@@ -466,7 +466,26 @@ Limitations
 
 - Modify Field flow:
 
-  - Supports the 'set' and 'add' operations for ``RTE_FLOW_ACTION_TYPE_MODIFY_FIELD`` action.
+  - Supports the 'set' operation for ``RTE_FLOW_ACTION_TYPE_MODIFY_FIELD`` in all flow engines.
+  - Supports the 'add' operation with 'src' field of type
+    ``RTE_FLOW_FIELD_VALUE`` or ``RTE_FLOW_FIELD_POINTER`` with both HW steering (``dv_flow_en=2``)
+    and DV flow engine (``dv_flow_en=1``).
+  - HW steering flow engine, starting with ConnectX-7 and BlueField-3,
+    supports packet header fields in 'src' field.
+    'dst' field can be any of the following:
+
+      - ``RTE_FLOW_FIELD_IPV4_TTL``
+      - ``RTE_FLOW_FIELD_IPV6_HOPLIMIT``
+      - ``RTE_FLOW_FIELD_TCP_SEQ_NUM``
+      - ``RTE_FLOW_FIELD_TCP_ACK_NUM``
+      - ``RTE_FLOW_FIELD_TAG``
+      - ``RTE_FLOW_FIELD_META``
+      - ``RTE_FLOW_FIELD_FLEX_ITEM``
+      - ``RTE_FLOW_FIELD_TCP_DATA_OFFSET``
+      - ``RTE_FLOW_FIELD_IPV4_IHL``
+      - ``RTE_FLOW_FIELD_IPV4_TOTAL_LEN``
+      - ``RTE_FLOW_FIELD_IPV6_PAYLOAD_LEN``
+
   - Modification of an arbitrary place in a packet via the special ``RTE_FLOW_FIELD_START`` Field ID is not supported.
   - Modification of the 802.1Q Tag, VXLAN Network or GENEVE Network ID's is not supported.
   - Encapsulation levels are not supported, can modify outermost header fields only.
diff --git a/drivers/net/mlx5/mlx5_flow_dv.c b/drivers/net/mlx5/mlx5_flow_dv.c
index f3a76f9e939..67c1f0b2aff 100644
--- a/drivers/net/mlx5/mlx5_flow_dv.c
+++ b/drivers/net/mlx5/mlx5_flow_dv.c
@@ -5084,6 +5084,13 @@ flow_dv_validate_action_modify_field(struct rte_eth_dev *dev,
 	}
 	if (action_modify_field->src.field != RTE_FLOW_FIELD_VALUE &&
 	    action_modify_field->src.field != RTE_FLOW_FIELD_POINTER) {
+		if (action_modify_field->operation != RTE_FLOW_MODIFY_SET)
+			return rte_flow_error_set(error, ENOTSUP,
+						  RTE_FLOW_ERROR_TYPE_ACTION_CONF,
+						  &action_modify_field->operation,
+						  "modify field action type add is not"
+						  " supported when src field type is"
+						  " not value/pointer");
 		if (root)
 			return rte_flow_error_set(error, ENOTSUP,
 					RTE_FLOW_ERROR_TYPE_ACTION, action,
-- 
2.21.0