[PATCH net V2 0/2] net/mlx5e: Report zero bandwidth for non-ETS traffic

[PATCH net V2 0/2] net/mlx5e: Report zero bandwidth for non-ETS traffic

[Tariq Toukan]

Hi,

The IEEE 802.1Qaz standard restricts bandwidth allocation percentages
to Enhanced Transmission Selection (ETS) traffic classes; STRICT,
VENDOR, and CB Shaper TSA types carry no bandwidth semantics.  Two
problems exist in the mlx5e DCBNL ETS implementation: the get path
reports 100% bandwidth for all TCs regardless of TSA type due to a
hardware limitation, introduced by commit 820c2c5e773d ("net/mlx5e:
Read ETS settings directly from firmware"), and the set path does
not reject the unsupported CB Shaper TSA, introduced by commit
08fb1dacdd76 ("net/mlx5e: Support DCBNL IEEE ETS").

This series by Alexei Lazar fixes the get path to report zero
bandwidth for non-ETS traffic classes, and rejects CB Shaper TSA
configurations that the driver does not support.

Regards,
Tariq

V2:
- Dropped patch 2 "net/mlx5e: Validate bandwidth for non-ETS
  traffic classes" (Jakub). We'll submit a more generic version of it.

V1:
https://lore.kernel.org/all/20260622112925.624795-1-tariqt@nvidia.com/

Alexei Lazar (2):
  net/mlx5e: Report zero bandwidth for non-ETS traffic classes
  net/mlx5e: Reject unsupported CB Shaper TSA in ETS validation

 .../net/ethernet/mellanox/mlx5/core/en_dcbnl.c    | 15 +++++++++++++++
 1 file changed, 15 insertions(+)


base-commit: 3f1f755366687d051174739fb99f7d560202f60b
-- 
2.44.0

[PATCH net V2 1/2] net/mlx5e: Report zero bandwidth for non-ETS traffic classes

[Tariq Toukan]

From: Alexei Lazar <alazar@nvidia.com>

The IEEE 802.1Qaz standard defines that bandwidth allocation percentages
only apply to Enhanced Transmission Selection (ETS) traffic classes.
For STRICT and VENDOR transmission selection algorithms, bandwidth
percentage values are not applicable.

Currently for non-ETS 100 bandwidth is being reported for all traffic
classes in the get operation due to hardware limitation, regardless of
their TSA type.

Fix this by reporting 0 for non-ETS traffic classes.

Fixes: 820c2c5e773d ("net/mlx5e: Read ETS settings directly from firmware")
Signed-off-by: Alexei Lazar <alazar@nvidia.com>
Reviewed-by: Carolina Jubran <cjubran@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c b/drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c
index 4b86df6d5b9e..762f0a46c120 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c
@@ -173,6 +173,13 @@ static int mlx5e_dcbnl_ieee_getets(struct net_device *netdev,
 	}
 	memcpy(ets->tc_tsa, priv->dcbx.tc_tsa, sizeof(ets->tc_tsa));
 
+	/* Report 0 for non ETS TSA */
+	for (i = 0; i < ets->ets_cap; i++) {
+		if (ets->tc_tx_bw[i] == MLX5E_MAX_BW_ALLOC &&
+		    priv->dcbx.tc_tsa[i] != IEEE_8021QAZ_TSA_ETS)
+			ets->tc_tx_bw[i] = 0;
+	}
+
 	return err;
 }
 
-- 
2.44.0

[PATCH net V2 2/2] net/mlx5e: Reject unsupported CB Shaper TSA in ETS validation

[Tariq Toukan]

From: Alexei Lazar <alazar@nvidia.com>

Credit Based (CB) TSA is not supported by the mlx5 driver, so reject
any configurations that specify it.

Fixes: 08fb1dacdd76 ("net/mlx5e: Support DCBNL IEEE ETS")
Signed-off-by: Alexei Lazar <alazar@nvidia.com>
Reviewed-by: Carolina Jubran <cjubran@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c b/drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c
index 762f0a46c120..00e706e1ede1 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c
@@ -324,6 +324,14 @@ static int mlx5e_dbcnl_validate_ets(struct net_device *netdev,
 		}
 	}
 
+	for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++) {
+		if (ets->tc_tsa[i] == IEEE_8021QAZ_TSA_CB_SHAPER) {
+			netdev_err(netdev,
+				   "Failed to validate ETS: CB Shaper is not supported\n");
+			return -EOPNOTSUPP;
+		}
+	}
+
 	/* Validate Bandwidth Sum */
 	for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++) {
 		if (ets->tc_tsa[i] == IEEE_8021QAZ_TSA_ETS) {
-- 
2.44.0