[PATCH v2] net/mlx5: fix MPLS/GRE Verbs spec ordering

[Dariusz Sosnowski]

When using Verbs flow engine to create flows, GRE Verbs spec was put at
the end of specs list. This created problems for flows matching MPLSoGRE
packets. In generated specs list MPLS spec was put before GRE spec, but
Verbs API requires that MPLS spec must be put in its exact location in
protocol stack.

This patch fixes this behavior. Space for GRE Verbs spec is reserved at
its exact location. MPLS Verbs is inserted at its exact location as
well. GRE spec is filled after all flow items are parsed.

Fixes: 985b479267aa ("net/mlx5: fix GRE protocol type translation for Verbs")
Cc: getelson at nvidia.com
Cc: stable at dpdk.org

Signed-off-by: Dariusz Sosnowski <dsosnowski at nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
---
v2:
* Rebased.

 drivers/net/mlx5/mlx5_flow_verbs.c | 49 +++++++++++++++++++++++++++---
 1 file changed, 44 insertions(+), 5 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_flow_verbs.c b/drivers/net/mlx5/mlx5_flow_verbs.c
index 85f0788222..fd902078f8 100644
--- a/drivers/net/mlx5/mlx5_flow_verbs.c
+++ b/drivers/net/mlx5/mlx5_flow_verbs.c
@@ -882,13 +882,48 @@ flow_verbs_item_gre_ip_protocol_update(struct ibv_flow_attr *attr,
 	}
 }
 
+/**
+ * Reserve space for GRE spec in spec buffer.
+ *
+ * @param[in,out] dev_flow
+ *   Pointer to dev_flow structure.
+ *
+ * @return
+ *   Pointer to reserved space in spec buffer.
+ */
+static uint8_t *
+flow_verbs_reserve_gre(struct mlx5_flow *dev_flow)
+{
+	uint8_t *buffer;
+	struct mlx5_flow_verbs_workspace *verbs = &dev_flow->verbs;
+#ifndef HAVE_IBV_DEVICE_MPLS_SUPPORT
+	unsigned int size = sizeof(struct ibv_flow_spec_tunnel);
+	struct ibv_flow_spec_tunnel tunnel = {
+		.type = IBV_FLOW_SPEC_VXLAN_TUNNEL,
+		.size = size,
+	};
+#else
+	unsigned int size = sizeof(struct ibv_flow_spec_gre);
+	struct ibv_flow_spec_gre tunnel = {
+		.type = IBV_FLOW_SPEC_GRE,
+		.size = size,
+	};
+#endif
+
+	buffer = verbs->specs + verbs->size;
+	flow_verbs_spec_add(verbs, &tunnel, size);
+	return buffer;
+}
+
 /**
  * Convert the @p item into a Verbs specification. This function assumes that
- * the input is valid and that there is space to insert the requested item
- * into the flow.
+ * the input is valid and that Verbs specification will be placed in
+ * the pre-reserved space.
  *
  * @param[in, out] dev_flow
  *   Pointer to dev_flow structure.
+ * @param[in, out] gre_spec
+ *   Pointer to space reserved for GRE spec.
  * @param[in] item
  *   Item specification.
  * @param[in] item_flags
@@ -896,6 +931,7 @@ flow_verbs_item_gre_ip_protocol_update(struct ibv_flow_attr *attr,
  */
 static void
 flow_verbs_translate_item_gre(struct mlx5_flow *dev_flow,
+			      uint8_t *gre_spec,
 			      const struct rte_flow_item *item __rte_unused,
 			      uint64_t item_flags)
 {
@@ -949,7 +985,8 @@ flow_verbs_translate_item_gre(struct mlx5_flow *dev_flow,
 		flow_verbs_item_gre_ip_protocol_update(&verbs->attr,
 						       IBV_FLOW_SPEC_IPV6,
 						       IPPROTO_GRE);
-	flow_verbs_spec_add(verbs, &tunnel, size);
+	MLX5_ASSERT(gre_spec);
+	memcpy(gre_spec, &tunnel, size);
 }
 
 /**
@@ -1680,6 +1717,7 @@ flow_verbs_translate(struct rte_eth_dev *dev,
 	struct mlx5_flow_workspace *wks = mlx5_flow_get_thread_workspace();
 	struct mlx5_flow_rss_desc *rss_desc;
 	const struct rte_flow_item *tunnel_item = NULL;
+	uint8_t *gre_spec = NULL;
 
 	MLX5_ASSERT(wks);
 	rss_desc = &wks->rss_desc;
@@ -1817,6 +1855,7 @@ flow_verbs_translate(struct rte_eth_dev *dev,
 			item_flags |= MLX5_FLOW_LAYER_VXLAN_GPE;
 			break;
 		case RTE_FLOW_ITEM_TYPE_GRE:
+			gre_spec = flow_verbs_reserve_gre(dev_flow);
 			subpriority = MLX5_TUNNEL_PRIO_GET(rss_desc);
 			item_flags |= MLX5_FLOW_LAYER_GRE;
 			tunnel_item = items;
@@ -1834,8 +1873,8 @@ flow_verbs_translate(struct rte_eth_dev *dev,
 		}
 	}
 	if (item_flags & MLX5_FLOW_LAYER_GRE)
-		flow_verbs_translate_item_gre(dev_flow, tunnel_item,
-					      item_flags);
+		flow_verbs_translate_item_gre(dev_flow, gre_spec,
+					      tunnel_item, item_flags);
 	dev_flow->handle->layers = item_flags;
 	/* Other members of attr will be ignored. */
 	dev_flow->verbs.attr.priority =
-- 
2.25.1