[PATCH] net/mlx5: fix the sample flow failure on the trusted device

[Jiawei Wang]

The flow with sample action will be split into two sub flows,
and a tag action was added implicitly in the sample prefix sub flow,
the reserved metadata regC index was used for this tag action.

The reserved metadata regC was shared with metering action,
for Connect-5 trusted device(VF/SF), the reserved metadata regC was
invalid since PF only supported the legacy metering.

This patch adds the checking for the tag index and back to use the
application tag if a failure happened.

Fixes: a9b6ea45bed6 ("net/mlx5: fix tag ID conflict with sample action")
Cc: stable at dpdk.org

Signed-off-by: Jiawei Wang <jiaweiw at nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
---
 doc/guides/nics/mlx5.rst        |  2 ++
 drivers/net/mlx5/mlx5_flow.c    |  6 ++++++
 drivers/net/mlx5/mlx5_flow_dv.c | 10 ++++++++++
 3 files changed, 18 insertions(+)

diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst
index a734d10d3f..ca7ebbe9cd 100644
--- a/doc/guides/nics/mlx5.rst
+++ b/doc/guides/nics/mlx5.rst
@@ -400,6 +400,8 @@ Limitations
     sample actions list.
   - For E-Switch mirroring flow, supports ``RAW ENCAP``, ``Port ID``,
     ``VXLAN ENCAP``, ``NVGRE ENCAP`` in the sample actions list.
+  - For ConnectX-5 trusted device, the application metadata with SET_TAG index 0
+    is not supported before ``RTE_FLOW_ACTION_TYPE_SAMPLE`` action.
 
 - Modify Field flow:
 
diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
index ffcaef0baa..e2bc6ce8ad 100644
--- a/drivers/net/mlx5/mlx5_flow.c
+++ b/drivers/net/mlx5/mlx5_flow.c
@@ -5881,6 +5881,12 @@ flow_sample_split_prep(struct rte_eth_dev *dev,
 		append_index++;
 		set_tag = (void *)(actions_pre + actions_n + append_index);
 		ret = mlx5_flow_get_reg_id(dev, MLX5_SAMPLE_ID, 0, error);
+		/* Trust VF/SF on CX5 not supported meter so that the reserved
+		 * metadata regC is REG_NON, back to use application tag
+		 * index 0.
+		 */
+		if (unlikely(ret == REG_NON))
+			ret = mlx5_flow_get_reg_id(dev, MLX5_APP_TAG, 0, error);
 		if (ret < 0)
 			return ret;
 		mlx5_ipool_malloc(priv->sh->ipool
diff --git a/drivers/net/mlx5/mlx5_flow_dv.c b/drivers/net/mlx5/mlx5_flow_dv.c
index 29751e7eda..ac21676416 100644
--- a/drivers/net/mlx5/mlx5_flow_dv.c
+++ b/drivers/net/mlx5/mlx5_flow_dv.c
@@ -6931,6 +6931,7 @@ flow_dv_validate(struct rte_eth_dev *dev, const struct rte_flow_attr *attr,
 	bool def_policy = false;
 	bool shared_count = false;
 	uint16_t udp_dport = 0;
+	uint32_t tag_id = 0;
 
 	if (items == NULL)
 		return -1;
@@ -7407,6 +7408,8 @@ flow_dv_validate(struct rte_eth_dev *dev, const struct rte_flow_attr *attr,
 				++actions_n;
 			if (action_flags & MLX5_FLOW_ACTION_SAMPLE)
 				modify_after_mirror = 1;
+			tag_id = ((const struct rte_flow_action_set_tag *)
+				  actions->conf)->index;
 			action_flags |= MLX5_FLOW_ACTION_SET_TAG;
 			rw_act_num += MLX5_ACT_NUM_SET_TAG;
 			break;
@@ -7841,6 +7844,13 @@ flow_dv_validate(struct rte_eth_dev *dev, const struct rte_flow_attr *attr,
 							     error);
 			if (ret < 0)
 				return ret;
+			if ((action_flags & MLX5_FLOW_ACTION_SET_TAG) &&
+			    tag_id == 0 && priv->mtr_color_reg == REG_NON)
+				return rte_flow_error_set
+					(error, EINVAL,
+					RTE_FLOW_ERROR_TYPE_ACTION,
+					NULL,
+					"Sample after Tag action cause metadata tag index 0 corruption");
 			action_flags |= MLX5_FLOW_ACTION_SAMPLE;
 			++actions_n;
 			break;
-- 
2.18.1