net/mlx5: add random item support

Add support for random item in HWS mode.

Signed-off-by: Michael Baum <michaelba@nvidia.com>
Acked-by: Dariusz Sosnowski <dsosnowski@nvidia.com>

doc/guides/nics/mlx5.rst

@@ -167,6 +167,7 @@ Features
 - Sub-Function.
 - Matching on represented port.
 - Matching on aggregated affinity.
+- Matching on random value.
 
 
 Limitations
@@ -571,6 +572,7 @@ Limitations
   - Modification of the MPLS header is supported only in HWS and only to copy from,
     the encapsulation level is always 0.
   - Modification of the 802.1Q Tag, VXLAN Network or GENEVE Network ID's is not supported.
+  - Modify field action using ``RTE_FLOW_FIELD_RANDOM`` is not supported.
   - Encapsulation levels are not supported, can modify outermost header fields only.
   - Offsets cannot skip past the boundary of a field.
   - If the field type is ``RTE_FLOW_FIELD_MAC_TYPE``
@@ -777,6 +779,13 @@ Limitations
   - In HW steering (``dv_flow_en`` = 2):
     - not supported on guest port.
 
+- Match on random value:
+
+  - Supported only with HW Steering enabled (``dv_flow_en`` = 2).
+  - Supported only in table with ``nb_flows=1``.
+  - NIC ingress/egress flow in group 0 is not supported.
+  - Supports matching only 16 bits (LSB).
+
 - During live migration to a new process set its flow engine as standby mode,
   the user should only program flow rules in group 0 (``fdb_def_rule_en=0``).
   Live migration is only supported under SWS (``dv_flow_en=1``).

doc/guides/rel_notes/release_24_03.rst

@@ -75,6 +75,7 @@ New Features
   * Added support for VXLAN-GPE matching in HW Steering flow engine
     (``dv_flow_en`` = 2).
 
+  * Added support for ``RTE_FLOW_ITEM_TYPE_RANDOM`` flow item.
 
 Removed Items
 -------------

drivers/net/mlx5/mlx5_flow_dv.c

@@ -5496,6 +5496,11 @@ flow_dv_validate_action_modify_field(struct rte_eth_dev *dev,
 				RTE_FLOW_ERROR_TYPE_ACTION, action,
 				"modifications of the MPLS header "
 				"is not supported");
+	if (dst_data->field == RTE_FLOW_FIELD_RANDOM ||
+	    src_data->field == RTE_FLOW_FIELD_RANDOM)
+		return rte_flow_error_set(error, ENOTSUP,
+				RTE_FLOW_ERROR_TYPE_ACTION, action,
+				"modifications of random value is not supported");
 	if (dst_data->field == RTE_FLOW_FIELD_MARK ||
 	    src_data->field == RTE_FLOW_FIELD_MARK)
 		if (config->dv_xmeta_en == MLX5_XMETA_MODE_LEGACY ||

drivers/net/mlx5/mlx5_flow_hw.c

@@ -5085,6 +5085,10 @@ flow_hw_validate_action_modify_field(struct rte_eth_dev *dev,
 		return rte_flow_error_set(error, EINVAL,
 				RTE_FLOW_ERROR_TYPE_ACTION, action,
 				"modifying vlan_type is not supported");
+	if (flow_hw_modify_field_is_used(action_conf, RTE_FLOW_FIELD_RANDOM))
+		return rte_flow_error_set(error, EINVAL,
+				RTE_FLOW_ERROR_TYPE_ACTION, action,
+				"modifying random value is not supported");
 	if (flow_hw_modify_field_is_used(action_conf, RTE_FLOW_FIELD_GENEVE_VNI))
 		return rte_flow_error_set(error, EINVAL,
 				RTE_FLOW_ERROR_TYPE_ACTION, action,
@@ -6851,6 +6855,7 @@ flow_hw_pattern_validate(struct rte_eth_dev *dev,
 		case RTE_FLOW_ITEM_TYPE_FLEX:
 		case RTE_FLOW_ITEM_TYPE_IB_BTH:
 		case RTE_FLOW_ITEM_TYPE_PTYPE:
+		case RTE_FLOW_ITEM_TYPE_RANDOM:
 			break;
 		case RTE_FLOW_ITEM_TYPE_INTEGRITY:
 			/*