[PATCH v5 3/3] net/mlx5: implement VXLAN last reserved modification

[Rongwei Liu <rongweil@nvidia.com>]

Implementing the VxLAN last reserved byte modification.
Following the RFC, the field is only 1 byte and needs to
use the field_length as 8 instead of the real dst_field->size.

Signed-off-by: Rongwei Liu <rongweil@nvidia.com>
Acked-by: Dariusz Sosnowski <dsosnowski@nvidia.com>
---
 doc/guides/nics/mlx5.rst        |  5 +++++
 drivers/net/mlx5/mlx5_flow_dv.c | 12 ++++++++++++
 drivers/net/mlx5/mlx5_flow_hw.c |  5 +++++
 3 files changed, 22 insertions(+)

diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst
index b5928d40b2..8b3aaf5aac 100644
--- a/doc/guides/nics/mlx5.rst
+++ b/doc/guides/nics/mlx5.rst
@@ -637,6 +637,11 @@ Limitations
   - Modify field action using ``RTE_FLOW_FIELD_RANDOM`` is not supported.
   - Modification of the 802.1Q tag is not supported.
   - Modification of VXLAN network or GENEVE network ID is supported only for HW steering.
+  - Modification of the VXLAN header is supported with below limitations:
+
+    - Only for HW steering (``dv_flow_en=2``).
+    - Support VNI and the last reserved byte modifications for traffic with default
+      UDP destination port. 4789 for VXLAN and VXLAN-GBP, 4790 for VXLAN-GPE.
   - Modification of GENEVE network ID is not supported when configured
     ``FLEX_PARSER_PROFILE_ENABLE`` supports Geneve TLV options.
     See :ref:`mlx5_firmware_config` for more flex parser information.
diff --git a/drivers/net/mlx5/mlx5_flow_dv.c b/drivers/net/mlx5/mlx5_flow_dv.c
index 06f5427abf..99abb2f2fb 100644
--- a/drivers/net/mlx5/mlx5_flow_dv.c
+++ b/drivers/net/mlx5/mlx5_flow_dv.c
@@ -1439,6 +1439,8 @@ mlx5_flow_item_field_width(struct rte_eth_dev *dev,
 	case RTE_FLOW_FIELD_VXLAN_VNI:
 	case RTE_FLOW_FIELD_GENEVE_VNI:
 		return 24;
+	case RTE_FLOW_FIELD_VXLAN_LAST_RSVD:
+		return 8;
 	case RTE_FLOW_FIELD_GTP_TEID:
 	case RTE_FLOW_FIELD_MPLS:
 	case RTE_FLOW_FIELD_TAG:
@@ -2038,6 +2040,16 @@ mlx5_flow_field_id_to_modify_info
 		else
 			info[idx].offset = off_be;
 		break;
+	case RTE_FLOW_FIELD_VXLAN_LAST_RSVD:
+		MLX5_ASSERT(data->offset + width <= 8);
+		/* Last_rsvd is on bits 7-0 of TUNNEL_HDR_DW_1. */
+		off_be = 8 - (data->offset + width);
+		info[idx] = (struct field_modify_info){1, 0, MLX5_MODI_TUNNEL_HDR_DW_1};
+		if (mask)
+			mask[idx] = flow_modify_info_mask_8(width, off_be);
+		else
+			info[idx].offset = off_be;
+		break;
 	case RTE_FLOW_FIELD_GENEVE_OPT_TYPE:
 		MLX5_ASSERT(data->offset + width <= 8);
 		modi_id = flow_geneve_opt_modi_field_get(priv, data);
diff --git a/drivers/net/mlx5/mlx5_flow_hw.c b/drivers/net/mlx5/mlx5_flow_hw.c
index 63194935a3..01362ae121 100644
--- a/drivers/net/mlx5/mlx5_flow_hw.c
+++ b/drivers/net/mlx5/mlx5_flow_hw.c
@@ -1385,6 +1385,10 @@ flow_hw_modify_field_compile(struct rte_eth_dev *dev,
 			value = *(const uint8_t *)item.spec;
 			value = rte_cpu_to_be_32(value << 8);
 			item.spec = &value;
+		} else if (conf->dst.field == RTE_FLOW_FIELD_VXLAN_LAST_RSVD) {
+			value = *(const uint8_t *)item.spec << 24;
+			value = rte_cpu_to_be_32(value);
+			item.spec = &value;
 		}
 	} else {
 		type = conf->operation == RTE_FLOW_MODIFY_SET ?
@@ -5580,6 +5584,7 @@ flow_hw_validate_modify_field_level(const struct rte_flow_field_data *data,
 	case RTE_FLOW_FIELD_ESP_SPI:
 	case RTE_FLOW_FIELD_ESP_SEQ_NUM:
 	case RTE_FLOW_FIELD_VXLAN_VNI:
+	case RTE_FLOW_FIELD_VXLAN_LAST_RSVD:
 	case RTE_FLOW_FIELD_GENEVE_VNI:
 	case RTE_FLOW_FIELD_GENEVE_OPT_TYPE:
 	case RTE_FLOW_FIELD_GENEVE_OPT_CLASS:
-- 
2.27.0