[dpdk-stable] [PATCH] net/mlx5: fix mirror flow split with L3 encapsulation

[Jiawei Wang]

Due to hardware limitations, the decap action can't follow the
sample action in the same flow, to keep the original action order
of sample and decap actions the flow was internally split by PMD,
and decap action was moved into suffix subflow in the new table.

There is a specific combination of raw decap and raw encap actions
to specify "L3 encapsulation" packet transformation - raw decap action
to remove L2 header and raw encap to add the tunnel header.
This specific L3 encapsulation is encoded as a single packet reformat
hardware transaction and is supported by hardware after sample
action (no hardware limitations for packet reformat).

The patch checks whether the decap action is the part of "L3 encapsulation"
and does not move the decap action into suffix subflow for the case.

Fixes: cafd87f62a06 ("net/mlx5: fix VLAN push/pop and decap actions with mirror")
Cc: stable at dpdk.org

Signed-off-by: Jiawei Wang <jiaweiw at nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
---
 drivers/net/mlx5/mlx5_flow.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
index a3fdce685e..3200a306e9 100644
--- a/drivers/net/mlx5/mlx5_flow.c
+++ b/drivers/net/mlx5/mlx5_flow.c
@@ -5259,6 +5259,7 @@ flow_check_match_action(const struct rte_flow_action actions[],
 			int *modify_after_mirror)
 {
 	const struct rte_flow_action_sample *sample;
+	const struct rte_flow_action_raw_decap *decap;
 	int actions_n = 0;
 	uint32_t ratio = 0;
 	int sub_type = 0;
@@ -5311,12 +5312,29 @@ flow_check_match_action(const struct rte_flow_action actions[],
 		case RTE_FLOW_ACTION_TYPE_OF_SET_VLAN_PCP:
 		case RTE_FLOW_ACTION_TYPE_VXLAN_DECAP:
 		case RTE_FLOW_ACTION_TYPE_NVGRE_DECAP:
-		case RTE_FLOW_ACTION_TYPE_RAW_DECAP:
 		case RTE_FLOW_ACTION_TYPE_MODIFY_FIELD:
 		case RTE_FLOW_ACTION_TYPE_METER:
 			if (fdb_mirror)
 				*modify_after_mirror = 1;
 			break;
+		case RTE_FLOW_ACTION_TYPE_RAW_DECAP:
+			decap = actions->conf;
+			while ((++actions)->type == RTE_FLOW_ACTION_TYPE_VOID)
+				;
+			actions_n++;
+			if (actions->type == RTE_FLOW_ACTION_TYPE_RAW_ENCAP) {
+				const struct rte_flow_action_raw_encap *encap =
+								actions->conf;
+				if (decap->size <=
+					MLX5_ENCAPSULATION_DECISION_SIZE &&
+				    encap->size >
+					MLX5_ENCAPSULATION_DECISION_SIZE)
+					/* L3 encap. */
+					break;
+			}
+			if (fdb_mirror)
+				*modify_after_mirror = 1;
+			break;
 		default:
 			break;
 		}
-- 
2.18.1