[RFC PATCH v3] ethdev: advertise flow restore in mbuf

[David Marchand <david.marchand@redhat.com>]

As reported by Ilya [1], unconditionally calling
rte_flow_get_restore_info() impacts an application performance for drivers
that do not provide this ops.
It could also impact processing of packets that require no call to
rte_flow_get_restore_info() at all.

Register a dynamic mbuf flag when an application negotiates tunnel
metadata delivery (calling rte_eth_rx_metadata_negotiate() with
RTE_ETH_RX_METADATA_TUNNEL_ID).

Drivers then advertise that metadata can be extracted by setting this
dynamic flag in each mbuf.

The application then calls rte_flow_get_restore_info() only when required.

Link: http://inbox.dpdk.org/dev/5248c2ca-f2a6-3fb0-38b8-7f659bfa40de@ovn.org/
Signed-off-by: David Marchand <david.marchand@redhat.com>
---
Changes since RFC v2:
- fixed crash introduced in v2 and removed unneeded argument to 
  rte_flow_restore_info_dynflag_register(),

Changes since RFC v1:
- rebased,
- updated vectorized datapath functions for net/mlx5,
- moved dynamic flag register to rte_eth_rx_metadata_negotiate() and
  hid rte_flow_restore_info_dynflag_register() into ethdev internals,

---
 app/test-pmd/util.c                      |  9 +++--
 drivers/net/mlx5/mlx5.c                  |  2 +
 drivers/net/mlx5/mlx5.h                  |  5 ++-
 drivers/net/mlx5/mlx5_flow.c             | 47 +++++++++++++++++++++---
 drivers/net/mlx5/mlx5_rx.c               |  2 +-
 drivers/net/mlx5/mlx5_rx.h               |  1 +
 drivers/net/mlx5/mlx5_rxtx_vec_altivec.h | 16 ++++----
 drivers/net/mlx5/mlx5_rxtx_vec_neon.h    |  6 +--
 drivers/net/mlx5/mlx5_rxtx_vec_sse.h     |  6 +--
 drivers/net/mlx5/mlx5_trigger.c          |  4 +-
 drivers/net/sfc/sfc_dp.c                 | 14 +------
 lib/ethdev/rte_ethdev.c                  |  5 +++
 lib/ethdev/rte_flow.c                    | 27 ++++++++++++++
 lib/ethdev/rte_flow.h                    | 18 ++++++++-
 lib/ethdev/rte_flow_driver.h             |  6 +++
 lib/ethdev/version.map                   |  1 +
 16 files changed, 128 insertions(+), 41 deletions(-)

diff --git a/app/test-pmd/util.c b/app/test-pmd/util.c
index f9df5f69ef..5aa69ed545 100644
--- a/app/test-pmd/util.c
+++ b/app/test-pmd/util.c
@@ -88,18 +88,20 @@ dump_pkt_burst(uint16_t port_id, uint16_t queue, struct rte_mbuf *pkts[],
 	char print_buf[MAX_STRING_LEN];
 	size_t buf_size = MAX_STRING_LEN;
 	size_t cur_len = 0;
+	uint64_t restore_info_dynflag;
 
 	if (!nb_pkts)
 		return;
+	restore_info_dynflag = rte_flow_restore_info_dynflag();
 	MKDUMPSTR(print_buf, buf_size, cur_len,
 		  "port %u/queue %u: %s %u packets\n", port_id, queue,
 		  is_rx ? "received" : "sent", (unsigned int) nb_pkts);
 	for (i = 0; i < nb_pkts; i++) {
-		int ret;
 		struct rte_flow_error error;
 		struct rte_flow_restore_info info = { 0, };
 
 		mb = pkts[i];
+		ol_flags = mb->ol_flags;
 		if (rxq_share > 0)
 			MKDUMPSTR(print_buf, buf_size, cur_len, "port %u, ",
 				  mb->port);
@@ -107,8 +109,8 @@ dump_pkt_burst(uint16_t port_id, uint16_t queue, struct rte_mbuf *pkts[],
 		eth_type = RTE_BE_TO_CPU_16(eth_hdr->ether_type);
 		packet_type = mb->packet_type;
 		is_encapsulation = RTE_ETH_IS_TUNNEL_PKT(packet_type);
-		ret = rte_flow_get_restore_info(port_id, mb, &info, &error);
-		if (!ret) {
+		if ((ol_flags & restore_info_dynflag) != 0 &&
+				rte_flow_get_restore_info(port_id, mb, &info, &error) == 0) {
 			MKDUMPSTR(print_buf, buf_size, cur_len,
 				  "restore info:");
 			if (info.flags & RTE_FLOW_RESTORE_INFO_TUNNEL) {
@@ -153,7 +155,6 @@ dump_pkt_burst(uint16_t port_id, uint16_t queue, struct rte_mbuf *pkts[],
 			  " - pool=%s - type=0x%04x - length=%u - nb_segs=%d",
 			  mb->pool->name, eth_type, (unsigned int) mb->pkt_len,
 			  (int)mb->nb_segs);
-		ol_flags = mb->ol_flags;
 		if (ol_flags & RTE_MBUF_F_RX_RSS_HASH) {
 			MKDUMPSTR(print_buf, buf_size, cur_len,
 				  " - RSS hash=0x%x",
diff --git a/drivers/net/mlx5/mlx5.c b/drivers/net/mlx5/mlx5.c
index a75fa1b7f0..58fde3af22 100644
--- a/drivers/net/mlx5/mlx5.c
+++ b/drivers/net/mlx5/mlx5.c
@@ -2347,6 +2347,7 @@ const struct eth_dev_ops mlx5_dev_ops = {
 	.get_monitor_addr = mlx5_get_monitor_addr,
 	.count_aggr_ports = mlx5_count_aggr_ports,
 	.map_aggr_tx_affinity = mlx5_map_aggr_tx_affinity,
+	.rx_metadata_negotiate = mlx5_flow_rx_metadata_negotiate,
 };
 
 /* Available operations from secondary process. */
@@ -2372,6 +2373,7 @@ const struct eth_dev_ops mlx5_dev_sec_ops = {
 	.get_module_eeprom = mlx5_get_module_eeprom,
 	.count_aggr_ports = mlx5_count_aggr_ports,
 	.map_aggr_tx_affinity = mlx5_map_aggr_tx_affinity,
+	.rx_metadata_negotiate = mlx5_flow_rx_metadata_negotiate,
 };
 
 /* Available operations in flow isolated mode. */
diff --git a/drivers/net/mlx5/mlx5.h b/drivers/net/mlx5/mlx5.h
index 021049ad2b..bf464613f0 100644
--- a/drivers/net/mlx5/mlx5.h
+++ b/drivers/net/mlx5/mlx5.h
@@ -1745,6 +1745,7 @@ struct mlx5_priv {
 	unsigned int lb_used:1; /* Loopback queue is referred to. */
 	uint32_t mark_enabled:1; /* If mark action is enabled on rxqs. */
 	uint32_t num_lag_ports:4; /* Number of ports can be bonded. */
+	uint32_t tunnel_enabled:1; /* If tunnel offloading is enabled on rxqs. */
 	uint16_t domain_id; /* Switch domain identifier. */
 	uint16_t vport_id; /* Associated VF vport index (if any). */
 	uint32_t vport_meta_tag; /* Used for vport index match ove VF LAG. */
@@ -2154,7 +2155,9 @@ int mlx5_flow_query_counter(struct rte_eth_dev *dev, struct rte_flow *flow,
 int mlx5_flow_dev_dump_ipool(struct rte_eth_dev *dev, struct rte_flow *flow,
 		FILE *file, struct rte_flow_error *error);
 #endif
-void mlx5_flow_rxq_dynf_metadata_set(struct rte_eth_dev *dev);
+int mlx5_flow_rx_metadata_negotiate(struct rte_eth_dev *dev,
+	uint64_t *features);
+void mlx5_flow_rxq_dynf_set(struct rte_eth_dev *dev);
 int mlx5_flow_get_aged_flows(struct rte_eth_dev *dev, void **contexts,
 			uint32_t nb_contexts, struct rte_flow_error *error);
 int mlx5_validate_action_ct(struct rte_eth_dev *dev,
diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
index eb1d7a6be2..19e567401b 100644
--- a/drivers/net/mlx5/mlx5_flow.c
+++ b/drivers/net/mlx5/mlx5_flow.c
@@ -1796,6 +1796,38 @@ flow_rxq_flags_clear(struct rte_eth_dev *dev)
 	priv->sh->shared_mark_enabled = 0;
 }
 
+static uint64_t mlx5_restore_info_dynflag;
+
+int
+mlx5_flow_rx_metadata_negotiate(struct rte_eth_dev *dev, uint64_t *features)
+{
+	struct mlx5_priv *priv = dev->data->dev_private;
+	uint64_t supported = 0;
+
+	if (!is_tunnel_offload_active(dev)) {
+		supported |= RTE_ETH_RX_METADATA_USER_FLAG;
+		supported |= RTE_ETH_RX_METADATA_USER_MARK;
+		if ((*features & RTE_ETH_RX_METADATA_TUNNEL_ID) != 0) {
+			DRV_LOG(DEBUG,
+				"tunnel offload was not activated, consider setting dv_xmeta_en=%d",
+				MLX5_XMETA_MODE_MISS_INFO);
+		}
+	} else {
+		supported |= RTE_ETH_RX_METADATA_TUNNEL_ID;
+		if ((*features & RTE_ETH_RX_METADATA_TUNNEL_ID) != 0 &&
+				mlx5_restore_info_dynflag == 0)
+			mlx5_restore_info_dynflag = rte_flow_restore_info_dynflag();
+	}
+
+	if (((*features & supported) & RTE_ETH_RX_METADATA_TUNNEL_ID) != 0)
+		priv->tunnel_enabled = 1;
+	else
+		priv->tunnel_enabled = 0;
+
+	*features &= supported;
+	return 0;
+}
+
 /**
  * Set the Rx queue dynamic metadata (mask and offset) for a flow
  *
@@ -1803,11 +1835,15 @@ flow_rxq_flags_clear(struct rte_eth_dev *dev)
  *   Pointer to the Ethernet device structure.
  */
 void
-mlx5_flow_rxq_dynf_metadata_set(struct rte_eth_dev *dev)
+mlx5_flow_rxq_dynf_set(struct rte_eth_dev *dev)
 {
 	struct mlx5_priv *priv = dev->data->dev_private;
+	uint64_t mark_flag = RTE_MBUF_F_RX_FDIR_ID;
 	unsigned int i;
 
+	if (priv->tunnel_enabled)
+		mark_flag |= mlx5_restore_info_dynflag;
+
 	for (i = 0; i != priv->rxqs_n; ++i) {
 		struct mlx5_rxq_priv *rxq = mlx5_rxq_get(dev, i);
 		struct mlx5_rxq_data *data;
@@ -1826,6 +1862,7 @@ mlx5_flow_rxq_dynf_metadata_set(struct rte_eth_dev *dev)
 			data->flow_meta_offset = rte_flow_dynf_metadata_offs;
 			data->flow_meta_port_mask = priv->sh->dv_meta_mask;
 		}
+		data->mark_flag = mark_flag;
 	}
 }
 
@@ -11560,12 +11597,10 @@ mlx5_flow_tunnel_get_restore_info(struct rte_eth_dev *dev,
 	uint64_t ol_flags = m->ol_flags;
 	const struct mlx5_flow_tbl_data_entry *tble;
 	const uint64_t mask = RTE_MBUF_F_RX_FDIR | RTE_MBUF_F_RX_FDIR_ID;
+	struct mlx5_priv *priv = dev->data->dev_private;
 
-	if (!is_tunnel_offload_active(dev)) {
-		info->flags = 0;
-		return 0;
-	}
-
+	if (priv->tunnel_enabled == 0)
+		goto err;
 	if ((ol_flags & mask) != mask)
 		goto err;
 	tble = tunnel_mark_decode(dev, m->hash.fdir.hi);
diff --git a/drivers/net/mlx5/mlx5_rx.c b/drivers/net/mlx5/mlx5_rx.c
index a2be523e9e..71c4638251 100644
--- a/drivers/net/mlx5/mlx5_rx.c
+++ b/drivers/net/mlx5/mlx5_rx.c
@@ -857,7 +857,7 @@ rxq_cq_to_mbuf(struct mlx5_rxq_data *rxq, struct rte_mbuf *pkt,
 		if (MLX5_FLOW_MARK_IS_VALID(mark)) {
 			pkt->ol_flags |= RTE_MBUF_F_RX_FDIR;
 			if (mark != RTE_BE32(MLX5_FLOW_MARK_DEFAULT)) {
-				pkt->ol_flags |= RTE_MBUF_F_RX_FDIR_ID;
+				pkt->ol_flags |= rxq->mark_flag;
 				pkt->hash.fdir.hi = mlx5_flow_mark_get(mark);
 			}
 		}
diff --git a/drivers/net/mlx5/mlx5_rx.h b/drivers/net/mlx5/mlx5_rx.h
index 52c35c83f8..3514edd84e 100644
--- a/drivers/net/mlx5/mlx5_rx.h
+++ b/drivers/net/mlx5/mlx5_rx.h
@@ -136,6 +136,7 @@ struct mlx5_rxq_data {
 	struct mlx5_uar_data uar_data; /* CQ doorbell. */
 	uint32_t cqn; /* CQ number. */
 	uint8_t cq_arm_sn; /* CQ arm seq number. */
+	uint64_t mark_flag; /* ol_flags to set with marks. */
 	uint32_t tunnel; /* Tunnel information. */
 	int timestamp_offset; /* Dynamic mbuf field for timestamp. */
 	uint64_t timestamp_rx_flag; /* Dynamic mbuf flag for timestamp. */
diff --git a/drivers/net/mlx5/mlx5_rxtx_vec_altivec.h b/drivers/net/mlx5/mlx5_rxtx_vec_altivec.h
index 14ffff26f4..4d0d05c376 100644
--- a/drivers/net/mlx5/mlx5_rxtx_vec_altivec.h
+++ b/drivers/net/mlx5/mlx5_rxtx_vec_altivec.h
@@ -296,15 +296,15 @@ rxq_cq_decompress_v(struct mlx5_rxq_data *rxq, volatile struct mlx5_cqe *cq,
 				const __vector unsigned char fdir_all_flags =
 					(__vector unsigned char)
 					(__vector unsigned int){
-					RTE_MBUF_F_RX_FDIR | RTE_MBUF_F_RX_FDIR_ID,
-					RTE_MBUF_F_RX_FDIR | RTE_MBUF_F_RX_FDIR_ID,
-					RTE_MBUF_F_RX_FDIR | RTE_MBUF_F_RX_FDIR_ID,
-					RTE_MBUF_F_RX_FDIR | RTE_MBUF_F_RX_FDIR_ID};
+					RTE_MBUF_F_RX_FDIR | rxq->mark_flag,
+					RTE_MBUF_F_RX_FDIR | rxq->mark_flag,
+					RTE_MBUF_F_RX_FDIR | rxq->mark_flag,
+					RTE_MBUF_F_RX_FDIR | rxq->mark_flag};
 				__vector unsigned char fdir_id_flags =
 					(__vector unsigned char)
 					(__vector unsigned int){
-					RTE_MBUF_F_RX_FDIR_ID, RTE_MBUF_F_RX_FDIR_ID,
-					RTE_MBUF_F_RX_FDIR_ID, RTE_MBUF_F_RX_FDIR_ID};
+					rxq->mark_flag, rxq->mark_flag,
+					rxq->mark_flag, rxq->mark_flag};
 				/* Extract flow_tag field. */
 				__vector unsigned char ftag0 = vec_perm(mcqe1,
 							zero, flow_mark_shuf);
@@ -632,8 +632,8 @@ rxq_cq_to_ptype_oflags_v(struct mlx5_rxq_data *rxq,
 			RTE_MBUF_F_RX_FDIR, RTE_MBUF_F_RX_FDIR};
 		__vector unsigned char fdir_id_flags =
 			(__vector unsigned char)(__vector unsigned int){
-			RTE_MBUF_F_RX_FDIR_ID, RTE_MBUF_F_RX_FDIR_ID,
-			RTE_MBUF_F_RX_FDIR_ID, RTE_MBUF_F_RX_FDIR_ID};
+			rxq->mark_flag, rxq->mark_flag,
+			rxq->mark_flag, rxq->mark_flag};
 		__vector unsigned char flow_tag, invalid_mask;
 
 		flow_tag = (__vector unsigned char)
diff --git a/drivers/net/mlx5/mlx5_rxtx_vec_neon.h b/drivers/net/mlx5/mlx5_rxtx_vec_neon.h
index 75e8ed7e5a..91c85bec6d 100644
--- a/drivers/net/mlx5/mlx5_rxtx_vec_neon.h
+++ b/drivers/net/mlx5/mlx5_rxtx_vec_neon.h
@@ -231,9 +231,9 @@ rxq_cq_decompress_v(struct mlx5_rxq_data *rxq, volatile struct mlx5_cqe *cq,
 					vdupq_n_u32(RTE_MBUF_F_RX_FDIR);
 				const uint32x4_t fdir_all_flags =
 					vdupq_n_u32(RTE_MBUF_F_RX_FDIR |
-						    RTE_MBUF_F_RX_FDIR_ID);
+						    rxq->mark_flag);
 				uint32x4_t fdir_id_flags =
-					vdupq_n_u32(RTE_MBUF_F_RX_FDIR_ID);
+					vdupq_n_u32(rxq->mark_flag);
 				uint32x4_t invalid_mask, ftag;
 
 				__asm__ volatile
@@ -446,7 +446,7 @@ rxq_cq_to_ptype_oflags_v(struct mlx5_rxq_data *rxq,
 	if (rxq->mark) {
 		const uint32x4_t ft_def = vdupq_n_u32(MLX5_FLOW_MARK_DEFAULT);
 		const uint32x4_t fdir_flags = vdupq_n_u32(RTE_MBUF_F_RX_FDIR);
-		uint32x4_t fdir_id_flags = vdupq_n_u32(RTE_MBUF_F_RX_FDIR_ID);
+		uint32x4_t fdir_id_flags = vdupq_n_u32(rxq->mark_flag);
 		uint32x4_t invalid_mask;
 
 		/* Check if flow tag is non-zero then set RTE_MBUF_F_RX_FDIR. */
diff --git a/drivers/net/mlx5/mlx5_rxtx_vec_sse.h b/drivers/net/mlx5/mlx5_rxtx_vec_sse.h
index b282f8b8e6..0766952255 100644
--- a/drivers/net/mlx5/mlx5_rxtx_vec_sse.h
+++ b/drivers/net/mlx5/mlx5_rxtx_vec_sse.h
@@ -214,9 +214,9 @@ rxq_cq_decompress_v(struct mlx5_rxq_data *rxq, volatile struct mlx5_cqe *cq,
 					_mm_set1_epi32(RTE_MBUF_F_RX_FDIR);
 				const __m128i fdir_all_flags =
 					_mm_set1_epi32(RTE_MBUF_F_RX_FDIR |
-						       RTE_MBUF_F_RX_FDIR_ID);
+						       rxq->mark_flag);
 				__m128i fdir_id_flags =
-					_mm_set1_epi32(RTE_MBUF_F_RX_FDIR_ID);
+					_mm_set1_epi32(rxq->mark_flag);
 
 				/* Extract flow_tag field. */
 				__m128i ftag0 =
@@ -442,7 +442,7 @@ rxq_cq_to_ptype_oflags_v(struct mlx5_rxq_data *rxq, __m128i cqes[4],
 	if (rxq->mark) {
 		const __m128i pinfo_ft_mask = _mm_set1_epi32(0xffffff00);
 		const __m128i fdir_flags = _mm_set1_epi32(RTE_MBUF_F_RX_FDIR);
-		__m128i fdir_id_flags = _mm_set1_epi32(RTE_MBUF_F_RX_FDIR_ID);
+		__m128i fdir_id_flags = _mm_set1_epi32(rxq->mark_flag);
 		__m128i flow_tag, invalid_mask;
 
 		flow_tag = _mm_and_si128(pinfo, pinfo_ft_mask);
diff --git a/drivers/net/mlx5/mlx5_trigger.c b/drivers/net/mlx5/mlx5_trigger.c
index bbaa7d2aa0..7bdb897612 100644
--- a/drivers/net/mlx5/mlx5_trigger.c
+++ b/drivers/net/mlx5/mlx5_trigger.c
@@ -1282,8 +1282,8 @@ mlx5_dev_start(struct rte_eth_dev *dev)
 			dev->data->port_id);
 		goto error;
 	}
-	/* Set a mask and offset of dynamic metadata flows into Rx queues. */
-	mlx5_flow_rxq_dynf_metadata_set(dev);
+	/* Set dynamic fields and flags into Rx queues. */
+	mlx5_flow_rxq_dynf_set(dev);
 	/* Set flags and context to convert Rx timestamps. */
 	mlx5_rxq_timestamp_set(dev);
 	/* Set a mask and offset of scheduling on timestamp into Tx queues. */
diff --git a/drivers/net/sfc/sfc_dp.c b/drivers/net/sfc/sfc_dp.c
index 9f2093b353..2b0a1d749d 100644
--- a/drivers/net/sfc/sfc_dp.c
+++ b/drivers/net/sfc/sfc_dp.c
@@ -11,6 +11,7 @@
 #include <string.h>
 #include <errno.h>
 
+#include <rte_ethdev.h>
 #include <rte_log.h>
 #include <rte_mbuf_dyn.h>
 
@@ -135,12 +136,8 @@ sfc_dp_ft_ctx_id_register(void)
 		.size = sizeof(uint8_t),
 		.align = __alignof__(uint8_t),
 	};
-	static const struct rte_mbuf_dynflag ft_ctx_id_valid = {
-		.name = "rte_net_sfc_dynflag_ft_ctx_id_valid",
-	};
 
 	int field_offset;
-	int flag;
 
 	SFC_GENERIC_LOG(INFO, "%s() entry", __func__);
 
@@ -156,15 +153,8 @@ sfc_dp_ft_ctx_id_register(void)
 		return -1;
 	}
 
-	flag = rte_mbuf_dynflag_register(&ft_ctx_id_valid);
-	if (flag < 0) {
-		SFC_GENERIC_LOG(ERR, "%s() failed to register ft_ctx_id dynflag",
-				__func__);
-		return -1;
-	}
-
+	sfc_dp_ft_ctx_id_valid = rte_flow_restore_info_dynflag();
 	sfc_dp_ft_ctx_id_offset = field_offset;
-	sfc_dp_ft_ctx_id_valid = UINT64_C(1) << flag;
 
 	SFC_GENERIC_LOG(INFO, "%s() done", __func__);
 
diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
index 7317015895..c8202a37ef 100644
--- a/lib/ethdev/rte_ethdev.c
+++ b/lib/ethdev/rte_ethdev.c
@@ -30,6 +30,7 @@
 #include "rte_ethdev.h"
 #include "rte_ethdev_trace_fp.h"
 #include "ethdev_driver.h"
+#include "rte_flow_driver.h"
 #include "ethdev_profile.h"
 #include "ethdev_private.h"
 #include "ethdev_trace.h"
@@ -6441,6 +6442,10 @@ rte_eth_rx_metadata_negotiate(uint16_t port_id, uint64_t *features)
 		return -EINVAL;
 	}
 
+	if ((*features & RTE_ETH_RX_METADATA_TUNNEL_ID) != 0 &&
+			rte_flow_restore_info_dynflag_register() < 0)
+		*features &= ~RTE_ETH_RX_METADATA_TUNNEL_ID;
+
 	if (*dev->dev_ops->rx_metadata_negotiate == NULL)
 		return -ENOTSUP;
 	ret = eth_err(port_id,
diff --git a/lib/ethdev/rte_flow.c b/lib/ethdev/rte_flow.c
index d41963b42e..271d854f78 100644
--- a/lib/ethdev/rte_flow.c
+++ b/lib/ethdev/rte_flow.c
@@ -1441,6 +1441,33 @@ rte_flow_get_restore_info(uint16_t port_id,
 				  NULL, rte_strerror(ENOTSUP));
 }
 
+static struct {
+	const struct rte_mbuf_dynflag desc;
+	uint64_t value;
+} flow_restore_info_dynflag = {
+	.desc = { .name = "RTE_MBUF_F_RX_RESTORE_INFO", },
+};
+
+uint64_t
+rte_flow_restore_info_dynflag(void)
+{
+	return flow_restore_info_dynflag.value;
+}
+
+int
+rte_flow_restore_info_dynflag_register(void)
+{
+	if (flow_restore_info_dynflag.value == 0) {
+		int offset = rte_mbuf_dynflag_register(&flow_restore_info_dynflag.desc);
+
+		if (offset < 0)
+			return -1;
+		flow_restore_info_dynflag.value = RTE_BIT64(offset);
+	}
+
+	return 0;
+}
+
 int
 rte_flow_tunnel_action_decap_release(uint16_t port_id,
 				     struct rte_flow_action *actions,
diff --git a/lib/ethdev/rte_flow.h b/lib/ethdev/rte_flow.h
index dec454275f..261d95378b 100644
--- a/lib/ethdev/rte_flow.h
+++ b/lib/ethdev/rte_flow.h
@@ -5128,7 +5128,23 @@ rte_flow_tunnel_match(uint16_t port_id,
 		      struct rte_flow_error *error);
 
 /**
- * Populate the current packet processing state, if exists, for the given mbuf.
+ * On reception of a mbuf from HW, a call to rte_flow_get_restore_info() may be
+ * required to retrieve some metadata.
+ * This function returns the associated mbuf ol_flags.
+ *
+ * Note: the dynamic flag is registered during a call to
+ * rte_eth_rx_metadata_negotiate() with RTE_ETH_RX_METADATA_TUNNEL_ID.
+ *
+ * @return
+ *   The offload flag indicating rte_flow_get_restore_info() must be called.
+ */
+__rte_experimental
+uint64_t
+rte_flow_restore_info_dynflag(void);
+
+/**
+ * If a mbuf contains the rte_flow_restore_info_dynflag() flag in ol_flags,
+ * populate the current packet processing state.
  *
  * One should negotiate tunnel metadata delivery from the NIC to the HW.
  * @see rte_eth_rx_metadata_negotiate()
diff --git a/lib/ethdev/rte_flow_driver.h b/lib/ethdev/rte_flow_driver.h
index 356b60f523..f9fb01b8a2 100644
--- a/lib/ethdev/rte_flow_driver.h
+++ b/lib/ethdev/rte_flow_driver.h
@@ -376,6 +376,12 @@ struct rte_flow_ops {
 const struct rte_flow_ops *
 rte_flow_ops_get(uint16_t port_id, struct rte_flow_error *error);
 
+/**
+ * Register mbuf dynamic flag for rte_flow_get_restore_info.
+ */
+int
+rte_flow_restore_info_dynflag_register(void);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/ethdev/version.map b/lib/ethdev/version.map
index 1a33d72668..0031be32bf 100644
--- a/lib/ethdev/version.map
+++ b/lib/ethdev/version.map
@@ -311,6 +311,7 @@ EXPERIMENTAL {
 	rte_flow_async_action_list_handle_destroy;
 	rte_flow_async_action_list_handle_query_update;
 	rte_flow_async_actions_update;
+	rte_flow_restore_info_dynflag;
 };
 
 INTERNAL {
-- 
2.40.1