net/mlx5: add MPLS modify field support

index ed3d5efbb7..04c1400a1e 100644
@@ -787,6 +787,11 @@ enum mlx5_modification_field {
 	MLX5_MODI_TUNNEL_HDR_DW_1 = 0x75,
 	MLX5_MODI_GTPU_FIRST_EXT_DW_0 = 0x76,
 	MLX5_MODI_HASH_RESULT = 0x81,
+	MLX5_MODI_IN_MPLS_LABEL_0 = 0x8a,
+	MLX5_MODI_IN_MPLS_LABEL_1,
+	MLX5_MODI_IN_MPLS_LABEL_2,
+	MLX5_MODI_IN_MPLS_LABEL_3,
+	MLX5_MODI_IN_MPLS_LABEL_4,
 	MLX5_MODI_OUT_IPV6_NEXT_HDR = 0x4A,
 	MLX5_MODI_INVALID = INT_MAX,
 };

index f136f43b0a..93cce16a1e 100644
@@ -1388,6 +1388,7 @@ mlx5_flow_item_field_width(struct rte_eth_dev *dev,
 	case RTE_FLOW_FIELD_GENEVE_VNI:
 		return 24;
 	case RTE_FLOW_FIELD_GTP_TEID:
+	case RTE_FLOW_FIELD_MPLS:
 	case RTE_FLOW_FIELD_TAG:
 		return 32;
 	case RTE_FLOW_FIELD_MARK:

@@ -1435,6 +1436,12 @@ flow_modify_info_mask_32_masked(uint32_t length, uint32_t off, uint32_t post_mas
 	return rte_cpu_to_be_32(mask & post_mask);
 }
 
+static __rte_always_inline enum mlx5_modification_field
+mlx5_mpls_modi_field_get(const struct rte_flow_action_modify_data *data)
+{
+	return MLX5_MODI_IN_MPLS_LABEL_0 + data->sub_level;
+}
+
 static void
 mlx5_modify_flex_item(const struct rte_eth_dev *dev,
 		      const struct mlx5_flex_item *flex,

@@ -1893,6 +1900,16 @@ mlx5_flow_field_id_to_modify_info
 		else
 			info[idx].offset = off_be;
 		break;
+	case RTE_FLOW_FIELD_MPLS:
+		MLX5_ASSERT(data->offset + width <= 32);
+		off_be = 32 - (data->offset + width);
+		info[idx] = (struct field_modify_info){4, 0,
+					mlx5_mpls_modi_field_get(data)};
+		if (mask)
+			mask[idx] = flow_modify_info_mask_32(width, off_be);
+		else
+			info[idx].offset = off_be;
+		break;
 	case RTE_FLOW_FIELD_TAG:
 		{
 			MLX5_ASSERT(data->offset + width <= 32);

@@ -5344,6 +5361,12 @@ flow_dv_validate_action_modify_field(struct rte_eth_dev *dev,
 				RTE_FLOW_ERROR_TYPE_ACTION, action,
 				"modifications of the GENEVE Network"
 				" Identifier is not supported");
+	if (action_modify_field->dst.field == RTE_FLOW_FIELD_MPLS ||
+	    action_modify_field->src.field == RTE_FLOW_FIELD_MPLS)
+		return rte_flow_error_set(error, ENOTSUP,
+				RTE_FLOW_ERROR_TYPE_ACTION, action,
+				"modifications of the MPLS header "
+				"is not supported");
 	if (action_modify_field->dst.field == RTE_FLOW_FIELD_MARK ||
 	    action_modify_field->src.field == RTE_FLOW_FIELD_MARK)
 		if (config->dv_xmeta_en == MLX5_XMETA_MODE_LEGACY ||

index 7e0ee8d883..fd2ad3bb58 100644
@@ -3546,10 +3546,8 @@ flow_hw_validate_action_modify_field(const struct rte_flow_action *action,
 				     const struct rte_flow_action *mask,
 				     struct rte_flow_error *error)
 {
-	const struct rte_flow_action_modify_field *action_conf =
-		action->conf;
-	const struct rte_flow_action_modify_field *mask_conf =
-		mask->conf;
+	const struct rte_flow_action_modify_field *action_conf = action->conf;
+	const struct rte_flow_action_modify_field *mask_conf = mask->conf;
 
 	if (action_conf->operation != mask_conf->operation)
 		return rte_flow_error_set(error, EINVAL,

@@ -3604,6 +3602,11 @@ flow_hw_validate_action_modify_field(const struct rte_flow_action *action,
 		return rte_flow_error_set(error, EINVAL,
 				RTE_FLOW_ERROR_TYPE_ACTION, action,
 				"modifying Geneve VNI is not supported");
+	/* Due to HW bug, tunnel MPLS header is read only. */
+	if (action_conf->dst.field == RTE_FLOW_FIELD_MPLS)
+		return rte_flow_error_set(error, EINVAL,
+				RTE_FLOW_ERROR_TYPE_ACTION, action,
+				"MPLS cannot be used as destination");
 	return 0;
 }
 

@@ -4134,9 +4137,8 @@ mlx5_flow_hw_actions_validate(struct rte_eth_dev *dev,
 			action_flags |= MLX5_FLOW_ACTION_METER;
 			break;
 		case RTE_FLOW_ACTION_TYPE_MODIFY_FIELD:
-			ret = flow_hw_validate_action_modify_field(action,
-									mask,
-									error);
+			ret = flow_hw_validate_action_modify_field(action, mask,
+								   error);
 			if (ret < 0)
 				return ret;
 			action_flags |= MLX5_FLOW_ACTION_MODIFY_FIELD;