[dpdk-dev] [PATCH v2] net/mlx5: fix zero value validation for metadata

[Wisam Jaddo <wisamm@mellanox.com>]

MARK and META items are interrelated with datapath -
they might move from/to the applications in mbuf.

zero value for these items has the special meaning -
it means "no metadata are provided", not zero values
are treated by applications and PMD as valid ones.

Moreover in the flow engine domain the value zero is
acceptable to match and set, and we should allow to
specify zero values as rte_flow parameters for the
META and MARK items and actions. In the same time
zero mask has no meaning and and should be rejected
on validation stage.

Fixes: fcc8d2f716fd ("net/mlx5: extend flow metadata support")
Fixes: e554b672aa05 ("net/mlx5: support flow tag")
Fixes: 55deee1715f0 ("net/mlx5: extend flow mark support")
Cc: viacheslavo@mellanox.com
Cc: stable@dpdk.org

Signed-off-by: Wisam Jaddo <wisamm@mellanox.com>
---
Changes in v2
- Fix commit message
- Fix documentation
- Remove extra line
- Always check for zero mask
---
---
 doc/guides/nics/mlx5.rst        | 12 ++++++++++++
 drivers/net/mlx5/mlx5_flow_dv.c | 19 +++++++++++++++----
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst
index e8f9984df0..e13c07d9ab 100644
--- a/doc/guides/nics/mlx5.rst
+++ b/doc/guides/nics/mlx5.rst
@@ -1275,6 +1275,18 @@ Supported hardware offloads
    |                       | |  ConnectX-5   | | ConnectX-5    |
    +-----------------------+-----------------+-----------------+
 
+Notes for metadata
+------------------
+MARK and META items are interrelated with datapath - they might move from/to
+the applications in mbuf fields. Hence, zero value for these items has the
+special meaning - it means "no metadata are provided", not zero values are
+treated by applications and PMD as valid ones.
+
+Moreover in the flow engine domain the value zero is acceptable to match and
+set, and we should allow to specify zero values as rte_flow parameters for the
+META and MARK items and actions. In the same time zero mask has no meaning and
+should be rejected on validation stage.
+
 Notes for testpmd
 -----------------
 
diff --git a/drivers/net/mlx5/mlx5_flow_dv.c b/drivers/net/mlx5/mlx5_flow_dv.c
index 809833b7ee..da4a925404 100644
--- a/drivers/net/mlx5/mlx5_flow_dv.c
+++ b/drivers/net/mlx5/mlx5_flow_dv.c
@@ -1406,6 +1406,11 @@ flow_dv_validate_item_mark(struct rte_eth_dev *dev,
 					  "mark id exceeds the limit");
 	if (!mask)
 		mask = &nic_mask;
+	if (!mask->id)
+		return rte_flow_error_set(error, EINVAL,
+					RTE_FLOW_ERROR_TYPE_ITEM_SPEC, NULL,
+					"mask cannot be zero");
+
 	ret = mlx5_flow_item_acceptable(item, (const uint8_t *)mask,
 					(const uint8_t *)&nic_mask,
 					sizeof(struct rte_flow_item_mark),
@@ -1451,10 +1456,6 @@ flow_dv_validate_item_meta(struct rte_eth_dev *dev __rte_unused,
 					  RTE_FLOW_ERROR_TYPE_ITEM_SPEC,
 					  item->spec,
 					  "data cannot be empty");
-	if (!spec->data)
-		return rte_flow_error_set(error, EINVAL,
-					  RTE_FLOW_ERROR_TYPE_ITEM_SPEC, NULL,
-					  "data cannot be zero");
 	if (config->dv_xmeta_en != MLX5_XMETA_MODE_LEGACY) {
 		if (!mlx5_flow_ext_mreg_supported(dev))
 			return rte_flow_error_set(error, ENOTSUP,
@@ -1474,6 +1475,11 @@ flow_dv_validate_item_meta(struct rte_eth_dev *dev __rte_unused,
 	}
 	if (!mask)
 		mask = &rte_flow_item_meta_mask;
+	if (!mask->data)
+		return rte_flow_error_set(error, EINVAL,
+					RTE_FLOW_ERROR_TYPE_ITEM_SPEC, NULL,
+					"mask cannot be zero");
+
 	ret = mlx5_flow_item_acceptable(item, (const uint8_t *)mask,
 					(const uint8_t *)&nic_mask,
 					sizeof(struct rte_flow_item_meta),
@@ -1522,6 +1528,11 @@ flow_dv_validate_item_tag(struct rte_eth_dev *dev,
 					  "data cannot be empty");
 	if (!mask)
 		mask = &rte_flow_item_tag_mask;
+	if (!mask->data)
+		return rte_flow_error_set(error, EINVAL,
+					RTE_FLOW_ERROR_TYPE_ITEM_SPEC, NULL,
+					"mask cannot be zero");
+
 	ret = mlx5_flow_item_acceptable(item, (const uint8_t *)mask,
 					(const uint8_t *)&nic_mask,
 					sizeof(struct rte_flow_item_tag),
-- 
2.17.1