diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst
index 1134290564..e99fea4342 100644
--- a/doc/guides/nics/mlx5.rst
+++ b/doc/guides/nics/mlx5.rst
@@ -371,6 +371,13 @@ Limitations
   - The E-Switch Sample flow must have the eswitch_manager VPORT destination (PF or ECPF) and no additional actions.
   - For ConnectX-5, the ``RTE_FLOW_ACTION_TYPE_SAMPLE`` is typically used as first action in the E-Switch egress flow if with header modify or encapsulation actions.
 
+- Modify Field flow:
+
+  - Supports the 'set' operation only for ``RTE_FLOW_ACTION_TYPE_MODIFY_FIELD`` action.
+  - Modification of an arbitrary place in a packet via the special ``RTE_FLOW_FIELD_START`` Field ID is not supported.
+  - Encapsulation levels are not supported, can modify outermost header fields only.
+  - Offsets must be 32-bits aligned, cannot skip past the boundary of a field.
+
 - IPv6 header item 'proto' field, indicating the next header protocol, should
   not be set as extension header.
   In case the next header is an extension header, it should not be specified in
@@ -1588,6 +1595,11 @@ Supported hardware offloads
    |                       | | rdma-core 34  | | rdma-core 34  |
    |                       | | ConnectX-6 Dx | | ConnectX-6 Dx |
    +-----------------------+-----------------+-----------------+
+   | Modify Field          | | DPDK 21.02    | | DPDK 21.02    |
+   |                       | | OFED 5.2      | | OFED 5.2      |
+   |                       | | rdma-core 35  | | rdma-core 35  |
+   |                       | | ConnectX-5    | | ConnectX-5    |
+   +-----------------------+-----------------+-----------------+
 
 Notes for metadata
 ------------------
diff --git a/doc/guides/rel_notes/release_21_02.rst b/doc/guides/rel_notes/release_21_02.rst
index f3a4a0dc4e..f651e94223 100644
--- a/doc/guides/rel_notes/release_21_02.rst
+++ b/doc/guides/rel_notes/release_21_02.rst
@@ -109,6 +109,7 @@ New Features
   * Enlarge the number of flow priorities to 21844(0 - 21843) for ingress or egress
     flow groups greater than 0 and for any transfer flow group.
   * Add support for the Tx mbuf fast free offload.
+  * Added support for RTE Flow modify field action.
 
 * **Updated Wangxun txgbe driver.**
 
diff --git a/drivers/net/mlx5/mlx5_flow.h b/drivers/net/mlx5/mlx5_flow.h
index 0b949f4a3a..a3a3c7f54f 100644
--- a/drivers/net/mlx5/mlx5_flow.h
+++ b/drivers/net/mlx5/mlx5_flow.h
@@ -219,6 +219,7 @@ enum mlx5_feature_name {
 #define MLX5_FLOW_ACTION_SAMPLE (1ull << 36)
 #define MLX5_FLOW_ACTION_TUNNEL_SET (1ull << 37)
 #define MLX5_FLOW_ACTION_TUNNEL_MATCH (1ull << 38)
+#define MLX5_FLOW_ACTION_MODIFY_FIELD (1ull << 39)
 
 #define MLX5_FLOW_FATE_ACTIONS \
 	(MLX5_FLOW_ACTION_DROP | MLX5_FLOW_ACTION_QUEUE | \
@@ -249,7 +250,8 @@ enum mlx5_feature_name {
 				      MLX5_FLOW_ACTION_MARK_EXT | \
 				      MLX5_FLOW_ACTION_SET_META | \
 				      MLX5_FLOW_ACTION_SET_IPV4_DSCP | \
-				      MLX5_FLOW_ACTION_SET_IPV6_DSCP)
+				      MLX5_FLOW_ACTION_SET_IPV6_DSCP | \
+				      MLX5_FLOW_ACTION_MODIFY_FIELD)
 
 #define MLX5_FLOW_VLAN_ACTIONS (MLX5_FLOW_ACTION_OF_POP_VLAN | \
 				MLX5_FLOW_ACTION_OF_PUSH_VLAN)
@@ -393,6 +395,9 @@ enum mlx5_feature_name {
 #define MLX5_ACT_NUM_SET_META		MLX5_ACT_NUM_SET_TAG
 #define MLX5_ACT_NUM_SET_DSCP		1
 
+/* Maximum number of fields to modify in MODIFY_FIELD */
+#define MLX5_ACT_MAX_MOD_FIELDS 5
+
 enum mlx5_flow_drv_type {
 	MLX5_FLOW_TYPE_MIN,
 	MLX5_FLOW_TYPE_DV,
diff --git a/drivers/net/mlx5/mlx5_flow_dv.c b/drivers/net/mlx5/mlx5_flow_dv.c
index be3c46d669..d5907a8f86 100644
--- a/drivers/net/mlx5/mlx5_flow_dv.c
+++ b/drivers/net/mlx5/mlx5_flow_dv.c
@@ -431,6 +431,7 @@ flow_dv_convert_modify_action(struct rte_flow_item *item,
 				(int)dcopy->offset < 0 ? off_b : dcopy->offset;
 			/* Convert entire record to big-endian format. */
 			actions[i].data1 = rte_cpu_to_be_32(actions[i].data1);
+			++dcopy;
 		} else {
 			MLX5_ASSERT(item->spec);
 			data = flow_dv_fetch_field((const uint8_t *)item->spec +
@@ -1324,6 +1325,511 @@ flow_dv_convert_action_modify_ipv6_dscp
 					     MLX5_MODIFICATION_TYPE_SET, error);
 }
 
+static void
+mlx5_flow_field_id_to_modify_info
+		(const struct rte_flow_action_modify_data *data,
+		 struct field_modify_info *info,
+		 uint32_t *mask, uint32_t *value, uint32_t width,
+		 struct rte_eth_dev *dev,
+		 const struct rte_flow_attr *attr,
+		 struct rte_flow_error *error)
+{
+	uint32_t idx = 0;
+	switch (data->field) {
+	case RTE_FLOW_FIELD_START:
+		/* not supported yet */
+		MLX5_ASSERT(false);
+		break;
+	case RTE_FLOW_FIELD_MAC_DST:
+		if (mask) {
+			if (data->offset < 32) {
+				info[idx] = (struct field_modify_info){4, 0,
+						MLX5_MODI_OUT_DMAC_47_16};
+				mask[idx] = 0xffffffff;
+				if (width < 32) {
+					mask[idx] = mask[idx] << (32 - width);
+					width = 0;
+				} else {
+					width -= 32;
+				}
+				if (!width)
+					break;
+				++idx;
+			}
+			info[idx] = (struct field_modify_info){2, 4 * idx,
+						MLX5_MODI_OUT_DMAC_15_0};
+			mask[idx] = (width) ? 0x0000ffff : 0x0;
+			if (width < 16)
+				mask[idx] = (mask[idx] << (16 - width)) &
+						0x0000ffff;
+		} else {
+			if (data->offset < 32)
+				info[idx++] = (struct field_modify_info){4, 0,
+						MLX5_MODI_OUT_DMAC_47_16};
+			info[idx] = (struct field_modify_info){2, 0,
+						MLX5_MODI_OUT_DMAC_15_0};
+		}
+		break;
+	case RTE_FLOW_FIELD_MAC_SRC:
+		if (mask) {
+			if (data->offset < 32) {
+				info[idx] = (struct field_modify_info){4, 0,
+						MLX5_MODI_OUT_SMAC_47_16};
+				mask[idx] = 0xffffffff;
+				if (width < 32) {
+					mask[idx] = mask[idx] << (32 - width);
+					width = 0;
+				} else {
+					width -= 32;
+				}
+				if (!width)
+					break;
+				++idx;
+			}
+			info[idx] = (struct field_modify_info){2, 4 * idx,
+						MLX5_MODI_OUT_SMAC_15_0};
+			mask[idx] = (width) ? 0x0000ffff : 0x0;
+			if (width < 16)
+				mask[idx] = (mask[idx] << (16 - width)) &
+						0x0000ffff;
+		} else {
+			if (data->offset < 32)
+				info[idx++] = (struct field_modify_info){4, 0,
+						MLX5_MODI_OUT_SMAC_47_16};
+			info[idx] = (struct field_modify_info){2, 0,
+						MLX5_MODI_OUT_SMAC_15_0};
+		}
+		break;
+	case RTE_FLOW_FIELD_VLAN_TYPE:
+		/* not supported yet */
+		break;
+	case RTE_FLOW_FIELD_VLAN_ID:
+		info[idx] = (struct field_modify_info){2, 0,
+					MLX5_MODI_OUT_FIRST_VID};
+		if (mask) {
+			mask[idx] = 0x0000ffff;
+			if (width < 16)
+				mask[idx] = (mask[idx] << (16 - width)) &
+						0x0000ffff;
+		}
+		break;
+	case RTE_FLOW_FIELD_MAC_TYPE:
+		info[idx] = (struct field_modify_info){2, 0,
+					MLX5_MODI_OUT_ETHERTYPE};
+		if (mask) {
+			mask[idx] = 0x0000ffff;
+			if (width < 16)
+				mask[idx] = (mask[idx] << (16 - width)) &
+						0x0000ffff;
+		}
+		break;
+	case RTE_FLOW_FIELD_IPV4_DSCP:
+		info[idx] = (struct field_modify_info){1, 0,
+					MLX5_MODI_OUT_IP_DSCP};
+		if (mask) {
+			mask[idx] = 0x0000003f;
+			if (width < 6)
+				mask[idx] = (mask[idx] << (6 - width)) &
+						0x0000003f;
+		}
+		break;
+	case RTE_FLOW_FIELD_IPV4_TTL:
+		info[idx] = (struct field_modify_info){1, 0,
+					MLX5_MODI_OUT_IPV4_TTL};
+		if (mask) {
+			mask[idx] = 0x000000ff;
+			if (width < 8)
+				mask[idx] = (mask[idx] << (8 - width)) &
+						0x000000ff;
+		}
+		break;
+	case RTE_FLOW_FIELD_IPV4_SRC:
+		info[idx] = (struct field_modify_info){4, 0,
+					MLX5_MODI_OUT_SIPV4};
+		if (mask) {
+			mask[idx] = 0xffffffff;
+			if (width < 32)
+				mask[idx] = mask[idx] << (32 - width);
+		}
+		break;
+	case RTE_FLOW_FIELD_IPV4_DST:
+		info[idx] = (struct field_modify_info){4, 0,
+					MLX5_MODI_OUT_DIPV4};
+		if (mask) {
+			mask[idx] = 0xffffffff;
+			if (width < 32)
+				mask[idx] = mask[idx] << (32 - width);
+		}
+		break;
+	case RTE_FLOW_FIELD_IPV6_DSCP:
+		info[idx] = (struct field_modify_info){1, 0,
+					MLX5_MODI_OUT_IP_DSCP};
+		if (mask) {
+			mask[idx] = 0x0000003f;
+			if (width < 6)
+				mask[idx] = (mask[idx] << (6 - width)) &
+						0x0000003f;
+		}
+		break;
+	case RTE_FLOW_FIELD_IPV6_HOPLIMIT:
+		info[idx] = (struct field_modify_info){1, 0,
+					MLX5_MODI_OUT_IPV6_HOPLIMIT};
+		if (mask) {
+			mask[idx] = 0x000000ff;
+			if (width < 8)
+				mask[idx] = (mask[idx] << (8 - width)) &
+						0x000000ff;
+		}
+		break;
+	case RTE_FLOW_FIELD_IPV6_SRC:
+		if (mask) {
+			if (data->offset < 32) {
+				info[idx] = (struct field_modify_info){4, 0,
+						MLX5_MODI_OUT_SIPV6_127_96};
+				mask[idx] = 0xffffffff;
+				if (width < 32) {
+					mask[idx] = mask[idx] << (32 - width);
+					width = 0;
+				} else {
+					width -= 32;
+				}
+				if (!width)
+					break;
+				++idx;
+			}
+			if (data->offset < 64) {
+				info[idx] = (struct field_modify_info){4,
+						4 * idx,
+						MLX5_MODI_OUT_SIPV6_95_64};
+				mask[idx] = 0xffffffff;
+				if (width < 32) {
+					mask[idx] = mask[idx] << (32 - width);
+					width = 0;
+				} else {
+					width -= 32;
+				}
+				if (!width)
+					break;
+				++idx;
+			}
+			if (data->offset < 96) {
+				info[idx] = (struct field_modify_info){4,
+						8 * idx,
+						MLX5_MODI_OUT_SIPV6_63_32};
+				mask[idx] = 0xffffffff;
+				if (width < 32) {
+					mask[idx] = mask[idx] << (32 - width);
+					width = 0;
+				} else {
+					width -= 32;
+				}
+				if (!width)
+					break;
+				++idx;
+			}
+			info[idx] = (struct field_modify_info){4, 12 * idx,
+						MLX5_MODI_OUT_SIPV6_31_0};
+			mask[idx] = 0xffffffff;
+			if (width < 32)
+				mask[idx] = mask[idx] << (32 - width);
+		} else {
+			if (data->offset < 32)
+				info[idx++] = (struct field_modify_info){4, 0,
+						MLX5_MODI_OUT_SIPV6_127_96};
+			if (data->offset < 64)
+				info[idx++] = (struct field_modify_info){4, 0,
+						MLX5_MODI_OUT_SIPV6_95_64};
+			if (data->offset < 96)
+				info[idx++] = (struct field_modify_info){4, 0,
+						MLX5_MODI_OUT_SIPV6_63_32};
+			if (data->offset < 128)
+				info[idx++] = (struct field_modify_info){4, 0,
+						MLX5_MODI_OUT_SIPV6_31_0};
+		}
+		break;
+	case RTE_FLOW_FIELD_IPV6_DST:
+		if (mask) {
+			if (data->offset < 32) {
+				info[idx] = (struct field_modify_info){4, 0,
+						MLX5_MODI_OUT_DIPV6_127_96};
+				mask[idx] = 0xffffffff;
+				if (width < 32) {
+					mask[idx] = mask[idx] << (32 - width);
+					width = 0;
+				} else {
+					width -= 32;
+				}
+				if (!width)
+					break;
+				++idx;
+			}
+			if (data->offset < 64) {
+				info[idx] = (struct field_modify_info){4,
+						4 * idx,
+						MLX5_MODI_OUT_DIPV6_95_64};
+				mask[idx] = 0xffffffff;
+				if (width < 32) {
+					mask[idx] = mask[idx] << (32 - width);
+					width = 0;
+				} else {
+					width -= 32;
+				}
+				if (!width)
+					break;
+				++idx;
+			}
+			if (data->offset < 96) {
+				info[idx] = (struct field_modify_info){4,
+						8 * idx,
+						MLX5_MODI_OUT_DIPV6_63_32};
+				mask[idx] = 0xffffffff;
+				if (width < 32) {
+					mask[idx] = mask[idx] << (32 - width);
+					width = 0;
+				} else {
+					width -= 32;
+				}
+				if (!width)
+					break;
+				++idx;
+			}
+			info[idx] = (struct field_modify_info){4, 12 * idx,
+						MLX5_MODI_OUT_DIPV6_31_0};
+			mask[idx] = 0xffffffff;
+			if (width < 32)
+				mask[idx] = mask[idx] << (32 - width);
+		} else {
+			if (data->offset < 32)
+				info[idx++] = (struct field_modify_info){4, 0,
+						MLX5_MODI_OUT_DIPV6_127_96};
+			if (data->offset < 64)
+				info[idx++] = (struct field_modify_info){4, 0,
+						MLX5_MODI_OUT_DIPV6_95_64};
+			if (data->offset < 96)
+				info[idx++] = (struct field_modify_info){4, 0,
+						MLX5_MODI_OUT_DIPV6_63_32};
+			if (data->offset < 128)
+				info[idx++] = (struct field_modify_info){4, 0,
+						MLX5_MODI_OUT_DIPV6_31_0};
+		}
+		break;
+	case RTE_FLOW_FIELD_TCP_PORT_SRC:
+		info[idx] = (struct field_modify_info){2, 0,
+					MLX5_MODI_OUT_TCP_SPORT};
+		if (mask) {
+			mask[idx] = 0x0000ffff;
+			if (width < 16)
+				mask[idx] = (mask[idx] << (16 - width)) &
+						0x0000ffff;
+		}
+		break;
+	case RTE_FLOW_FIELD_TCP_PORT_DST:
+		info[idx] = (struct field_modify_info){2, 0,
+					MLX5_MODI_OUT_TCP_DPORT};
+		if (mask) {
+			mask[idx] = 0x0000ffff;
+			if (width < 16)
+				mask[idx] = (mask[idx] << (16 - width)) &
+						0x0000ffff;
+		}
+		break;
+	case RTE_FLOW_FIELD_TCP_SEQ_NUM:
+		info[idx] = (struct field_modify_info){4, 0,
+					MLX5_MODI_OUT_TCP_SEQ_NUM};
+		if (mask) {
+			mask[idx] = 0x0000ffff;
+			if (width < 16)
+				mask[idx] = (mask[idx] << (16 - width)) &
+						0x0000ffff;
+		}
+		break;
+	case RTE_FLOW_FIELD_TCP_ACK_NUM:
+		info[idx] = (struct field_modify_info){4, 0,
+					MLX5_MODI_OUT_TCP_ACK_NUM};
+		if (mask) {
+			mask[idx] = 0x0000ffff;
+			if (width < 16)
+				mask[idx] = (mask[idx] << (16 - width)) &
+						0x0000ffff;
+		}
+		break;
+	case RTE_FLOW_FIELD_TCP_FLAGS:
+		info[idx] = (struct field_modify_info){1, 0,
+					MLX5_MODI_IN_TCP_FLAGS};
+		if (mask) {
+			mask[idx] = 0x0000003f;
+			if (width < 6)
+				mask[idx] = (mask[idx] << (6 - width)) &
+						0x0000003f;
+		}
+		break;
+	case RTE_FLOW_FIELD_UDP_PORT_SRC:
+		info[idx] = (struct field_modify_info){2, 0,
+					MLX5_MODI_OUT_UDP_SPORT};
+		if (mask) {
+			mask[idx] = 0x0000ffff;
+			if (width < 16)
+				mask[idx] = (mask[idx] << (16 - width)) &
+						0x0000ffff;
+		}
+		break;
+	case RTE_FLOW_FIELD_UDP_PORT_DST:
+		info[idx] = (struct field_modify_info){2, 0,
+					MLX5_MODI_OUT_UDP_DPORT};
+		if (mask) {
+			mask[idx] = 0x0000ffff;
+			if (width < 16)
+				mask[idx] = (mask[idx] << (16 - width)) &
+						0x0000ffff;
+		}
+		break;
+	case RTE_FLOW_FIELD_VXLAN_VNI:
+		/* not supported yet */
+		break;
+	case RTE_FLOW_FIELD_GENEVE_VNI:
+		/* not supported yet*/
+		break;
+	case RTE_FLOW_FIELD_GTP_TEID:
+		info[idx] = (struct field_modify_info){4, 0,
+					MLX5_MODI_GTP_TEID};
+		if (mask) {
+			mask[idx] = 0xffffffff;
+			if (width < 32)
+				mask[idx] = mask[idx] << (32 - width);
+		}
+		break;
+	case RTE_FLOW_FIELD_TAG:
+		{
+			int reg = mlx5_flow_get_reg_id(dev, MLX5_APP_TAG,
+						   data->level, error);
+			if (reg < 0)
+				return;
+			MLX5_ASSERT(reg != REG_NON);
+			MLX5_ASSERT((unsigned int)reg < RTE_DIM(reg_to_field));
+			info[idx] = (struct field_modify_info){4, 0,
+						reg_to_field[reg]};
+			if (mask) {
+				mask[idx] = 0xffffffff;
+				if (width < 32)
+					mask[idx] = mask[idx] << (32 - width);
+			}
+		}
+		break;
+	case RTE_FLOW_FIELD_MARK:
+		{
+			int reg = mlx5_flow_get_reg_id(dev, MLX5_FLOW_MARK,
+						       0, error);
+			if (reg < 0)
+				return;
+			MLX5_ASSERT(reg != REG_NON);
+			MLX5_ASSERT((unsigned int)reg < RTE_DIM(reg_to_field));
+			info[idx] = (struct field_modify_info){4, 0,
+						reg_to_field[reg]};
+			if (mask) {
+				mask[idx] = 0xffffffff;
+				if (width < 32)
+					mask[idx] = mask[idx] << (32 - width);
+			}
+		}
+		break;
+	case RTE_FLOW_FIELD_META:
+		{
+			int reg = flow_dv_get_metadata_reg(dev, attr, error);
+			if (reg < 0)
+				return;
+			MLX5_ASSERT(reg != REG_NON);
+			MLX5_ASSERT((unsigned int)reg < RTE_DIM(reg_to_field));
+			info[idx] = (struct field_modify_info){4, 0,
+						reg_to_field[reg]};
+			if (mask) {
+				mask[idx] = 0xffffffff;
+				if (width < 32)
+					mask[idx] = mask[idx] << (32 - width);
+			}
+		}
+		break;
+	case RTE_FLOW_FIELD_POINTER:
+		for (idx = 0; idx < MLX5_ACT_MAX_MOD_FIELDS; idx++) {
+			if (mask[idx]) {
+				value[idx] = RTE_BE32(*(uint64_t *)data->value);
+				break;
+			}
+		}
+		break;
+	case RTE_FLOW_FIELD_VALUE:
+		for (idx = 0; idx < MLX5_ACT_MAX_MOD_FIELDS; idx++) {
+			if (mask[idx]) {
+				value[idx] = RTE_BE32(data->value);
+				break;
+			}
+		}
+		break;
+	default:
+		MLX5_ASSERT(false);
+		break;
+	}
+}
+
+/**
+ * Convert modify_field action to DV specification.
+ *
+ * @param[in] dev
+ *   Pointer to the rte_eth_dev structure.
+ * @param[in,out] resource
+ *   Pointer to the modify-header resource.
+ * @param[in] action
+ *   Pointer to action specification.
+ * @param[in] attr
+ *   Attributes of flow that includes this item.
+ * @param[out] error
+ *   Pointer to the error structure.
+ *
+ * @return
+ *   0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+static int
+flow_dv_convert_action_modify_field
+			(struct rte_eth_dev *dev,
+			 struct mlx5_flow_dv_modify_hdr_resource *resource,
+			 const struct rte_flow_action *action,
+			 const struct rte_flow_attr *attr,
+			 struct rte_flow_error *error)
+{
+	const struct rte_flow_action_modify_field *conf =
+		(const struct rte_flow_action_modify_field *)(action->conf);
+	struct rte_flow_item item;
+	struct field_modify_info field[MLX5_ACT_MAX_MOD_FIELDS] = {
+								{0, 0, 0} };
+	struct field_modify_info dcopy[MLX5_ACT_MAX_MOD_FIELDS] = {
+								{0, 0, 0} };
+	uint32_t mask[MLX5_ACT_MAX_MOD_FIELDS] = {0, 0, 0, 0, 0};
+	uint32_t value[MLX5_ACT_MAX_MOD_FIELDS] = {0, 0, 0, 0, 0};
+	uint32_t type;
+
+	if (conf->src.field == RTE_FLOW_FIELD_POINTER ||
+		conf->src.field == RTE_FLOW_FIELD_VALUE) {
+		type = MLX5_MODIFICATION_TYPE_SET;
+		/** For SET fill the destination field (field) first. */
+		mlx5_flow_field_id_to_modify_info(&conf->dst, field, mask,
+					  value, conf->width, dev, attr, error);
+		/** Then copy immediate value from source as per mask. */
+		mlx5_flow_field_id_to_modify_info(&conf->src, dcopy, mask,
+					  value, conf->width, dev, attr, error);
+		item.spec = &value;
+	} else {
+		type = MLX5_MODIFICATION_TYPE_COPY;
+		/** For COPY fill the destination field (dcopy) without mask. */
+		mlx5_flow_field_id_to_modify_info(&conf->dst, dcopy, NULL,
+					  value, conf->width, dev, attr, error);
+		/** Then construct the source field (field) with mask. */
+		mlx5_flow_field_id_to_modify_info(&conf->src, field, mask,
+					  value, conf->width, dev, attr, error);
+	}
+	item.mask = &mask;
+	return flow_dv_convert_modify_action(&item,
+			field, dcopy, resource, type, error);
+}
+
 /**
  * Validate MARK item.
  *
@@ -3992,6 +4498,163 @@ flow_dv_validate_action_modify_ttl(const uint64_t action_flags,
 	return ret;
 }
 
+static int
+mlx5_flow_item_field_width(enum rte_flow_field_id field)
+{
+	switch (field) {
+	case RTE_FLOW_FIELD_START:
+		return 32;
+	case RTE_FLOW_FIELD_MAC_DST:
+	case RTE_FLOW_FIELD_MAC_SRC:
+		return 48;
+	case RTE_FLOW_FIELD_VLAN_TYPE:
+		return 16;
+	case RTE_FLOW_FIELD_VLAN_ID:
+		return 12;
+	case RTE_FLOW_FIELD_MAC_TYPE:
+		return 16;
+	case RTE_FLOW_FIELD_IPV4_DSCP:
+	case RTE_FLOW_FIELD_IPV4_TTL:
+		return 8;
+	case RTE_FLOW_FIELD_IPV4_SRC:
+	case RTE_FLOW_FIELD_IPV4_DST:
+		return 32;
+	case RTE_FLOW_FIELD_IPV6_DSCP:
+	case RTE_FLOW_FIELD_IPV6_HOPLIMIT:
+		return 8;
+	case RTE_FLOW_FIELD_IPV6_SRC:
+	case RTE_FLOW_FIELD_IPV6_DST:
+		return 128;
+	case RTE_FLOW_FIELD_TCP_PORT_SRC:
+	case RTE_FLOW_FIELD_TCP_PORT_DST:
+		return 16;
+	case RTE_FLOW_FIELD_TCP_SEQ_NUM:
+	case RTE_FLOW_FIELD_TCP_ACK_NUM:
+		return 32;
+	case RTE_FLOW_FIELD_TCP_FLAGS:
+		return 6;
+	case RTE_FLOW_FIELD_UDP_PORT_SRC:
+	case RTE_FLOW_FIELD_UDP_PORT_DST:
+		return 16;
+	case RTE_FLOW_FIELD_VXLAN_VNI:
+	case RTE_FLOW_FIELD_GENEVE_VNI:
+		return 24;
+	case RTE_FLOW_FIELD_GTP_TEID:
+	case RTE_FLOW_FIELD_TAG:
+		return 32;
+	case RTE_FLOW_FIELD_MARK:
+		return 24;
+	case RTE_FLOW_FIELD_META:
+	case RTE_FLOW_FIELD_POINTER:
+	case RTE_FLOW_FIELD_VALUE:
+		return 32;
+	default:
+		MLX5_ASSERT(false);
+	}
+	return 0;
+}
+
+/**
+ * Validate the generic modify field actions.
+ *
+ * @param[in] action_flags
+ *   Holds the actions detected until now.
+ * @param[in] action
+ *   Pointer to the modify action.
+ * @param[in] item_flags
+ *   Holds the items detected.
+ * @param[out] error
+ *   Pointer to error structure.
+ *
+ * @return
+ *   Number of header fields to modify (0 or more) on success,
+ *   a negative errno value otherwise and rte_errno is set.
+ */
+static int
+flow_dv_validate_action_modify_field(const uint64_t action_flags,
+				   const struct rte_flow_action *action,
+				   struct rte_flow_error *error)
+{
+	int ret = 0;
+	const struct rte_flow_action_modify_field *action_modify_field =
+		action->conf;
+	uint32_t dst_width =
+		mlx5_flow_item_field_width(action_modify_field->dst.field);
+	uint32_t src_width =
+		mlx5_flow_item_field_width(action_modify_field->src.field);
+
+	ret = flow_dv_validate_action_modify_hdr(action_flags, action, error);
+	if (ret)
+		return ret;
+
+	if (action_modify_field->dst.field != RTE_FLOW_FIELD_VALUE &&
+	    action_modify_field->dst.field != RTE_FLOW_FIELD_POINTER) {
+		if (action_modify_field->dst.offset >= dst_width ||
+		    (action_modify_field->dst.offset % 32))
+			return rte_flow_error_set(error, EINVAL,
+						RTE_FLOW_ERROR_TYPE_ACTION,
+						NULL,
+						"destination offset is too big"
+						" or not aligned to 4 bytes");
+		if (action_modify_field->dst.level &&
+		    action_modify_field->dst.field != RTE_FLOW_FIELD_TAG)
+			return rte_flow_error_set(error, EINVAL,
+						RTE_FLOW_ERROR_TYPE_ACTION,
+						NULL,
+						"cannot modify inner headers");
+	}
+	if (action_modify_field->src.field != RTE_FLOW_FIELD_VALUE &&
+	    action_modify_field->src.field != RTE_FLOW_FIELD_POINTER) {
+		if (action_modify_field->src.offset >= src_width ||
+		    (action_modify_field->src.offset % 32))
+			return rte_flow_error_set(error, EINVAL,
+						RTE_FLOW_ERROR_TYPE_ACTION,
+						NULL,
+						"source offset is too big"
+						" or not aligned to 4 bytes");
+		if (action_modify_field->src.level &&
+		    action_modify_field->src.field != RTE_FLOW_FIELD_TAG)
+			return rte_flow_error_set(error, EINVAL,
+						RTE_FLOW_ERROR_TYPE_ACTION,
+						NULL,
+						"cannot copy from inner headers");
+	}
+	if (action_modify_field->width == 0)
+		return rte_flow_error_set(error, EINVAL,
+						RTE_FLOW_ERROR_TYPE_ACTION,
+						NULL,
+						"width is required for modify action");
+	if (action_modify_field->dst.field ==
+	    action_modify_field->src.field)
+		return rte_flow_error_set(error, EINVAL,
+					RTE_FLOW_ERROR_TYPE_ACTION,
+					NULL,
+					"source and destination fields"
+					" cannot be the same");
+	if (action_modify_field->dst.field == RTE_FLOW_FIELD_VALUE ||
+	    action_modify_field->dst.field == RTE_FLOW_FIELD_POINTER)
+		return rte_flow_error_set(error, EINVAL,
+					RTE_FLOW_ERROR_TYPE_ACTION,
+					NULL,
+					"immediate value or a pointer to it"
+					" cannot be used as a destination");
+	if (action_modify_field->dst.field == RTE_FLOW_FIELD_START ||
+	    action_modify_field->src.field == RTE_FLOW_FIELD_START)
+		return rte_flow_error_set(error, EINVAL,
+				RTE_FLOW_ERROR_TYPE_ACTION,
+				NULL,
+				"modifications of an arbitrary"
+				" place in a packet is not supported");
+	if (action_modify_field->operation != RTE_FLOW_MODIFY_SET)
+		return rte_flow_error_set(error, EINVAL,
+				RTE_FLOW_ERROR_TYPE_ACTION,
+				NULL,
+				"add and sub operations"
+				" are not supported");
+	return (action_modify_field->width / 32) +
+	       !!(action_modify_field->width % 32);
+}
+
 /**
  * Validate jump action.
  *
@@ -5388,7 +6051,7 @@ flow_dv_validate(struct rte_eth_dev *dev, const struct rte_flow_attr *attr,
 	struct mlx5_dev_config *dev_conf = &priv->config;
 	uint16_t queue_index = 0xFFFF;
 	const struct rte_flow_item_vlan *vlan_m = NULL;
-	int16_t rw_act_num = 0;
+	uint32_t rw_act_num = 0;
 	uint64_t is_root;
 	const struct mlx5_flow_tunnel *tunnel;
 	struct flow_grp_info grp_info = {
@@ -6185,6 +6848,23 @@ flow_dv_validate(struct rte_eth_dev *dev, const struct rte_flow_attr *attr,
 
 			action_flags |= MLX5_FLOW_ACTION_TUNNEL_SET;
 			break;
+		case RTE_FLOW_ACTION_TYPE_MODIFY_FIELD:
+			if (!attr->transfer && !attr->group)
+				return rte_flow_error_set(error, ENOTSUP,
+						RTE_FLOW_ERROR_TYPE_ACTION,
+						NULL, "modify field action "
+						"is not supported for group 0");
+			ret = flow_dv_validate_action_modify_field(action_flags,
+								 actions,
+								 error);
+			if (ret < 0)
+				return ret;
+			/* Count all modify-header actions as one action. */
+			if (!(action_flags & MLX5_FLOW_ACTION_MODIFY_FIELD))
+				++actions_n;
+			action_flags |= MLX5_FLOW_ACTION_MODIFY_FIELD;
+			rw_act_num += ret;
+			break;
 		default:
 			return rte_flow_error_set(error, ENOTSUP,
 						  RTE_FLOW_ERROR_TYPE_ACTION,
@@ -6342,7 +7022,7 @@ flow_dv_validate(struct rte_eth_dev *dev, const struct rte_flow_attr *attr,
 	    dev_conf->dv_xmeta_en != MLX5_XMETA_MODE_LEGACY &&
 	    mlx5_flow_ext_mreg_supported(dev))
 		rw_act_num += MLX5_ACT_NUM_SET_TAG;
-	if ((uint32_t)rw_act_num >
+	if (rw_act_num >
 			flow_dv_modify_hdr_action_max(dev, is_root)) {
 		return rte_flow_error_set(error, ENOTSUP,
 					  RTE_FLOW_ERROR_TYPE_ACTION,
@@ -10692,6 +11372,12 @@ flow_dv_translate(struct rte_eth_dev *dev,
 				sample_act->action_flags |=
 							MLX5_FLOW_ACTION_ENCAP;
 			break;
+		case RTE_FLOW_ACTION_TYPE_MODIFY_FIELD:
+			if (flow_dv_convert_action_modify_field
+					(dev, mhdr_res, actions, attr, error))
+				return -rte_errno;
+			action_flags |= MLX5_FLOW_ACTION_MODIFY_FIELD;
+			break;
 		case RTE_FLOW_ACTION_TYPE_END:
 			actions_end = true;
 			if (mhdr_res->actions_num) {
