[PATCH net-next] net/mlx5e: Enable mac forwarding on uplink representor

[PATCH net-next] net/mlx5e: Enable mac forwarding on uplink representor

[Tariq Toukan]

From: Saeed Mahameed <saeedm@nvidia.com>

MAC forwarding and namely 'set_rx_mode' handler, was disabled on uplink
representor as they rely on FDB to forward all traffic to it by default,
which works perfectly on a single PF per physical port configuration.
But, in case of multi-host and DPU environments, uplink was stuck
with its own mac, since MPFs (Multi PF switch) requires PFs to request
explicit mac forwarding.

This small patch enables mac forwarding to MPFs via uplink representor,
by enabling only the mac (uc/mc) list handling logic in
mlx5e_set_rx_mode() handler for uplink representor netdevs.

Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_fs.c   | 10 ++++++++++
 drivers/net/ethernet/mellanox/mlx5/core/en_main.c |  3 ---
 drivers/net/ethernet/mellanox/mlx5/core/en_rep.c  |  2 ++
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c b/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c
index 9352e2183312..d7556d611155 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c
@@ -823,8 +823,14 @@ static void mlx5e_destroy_promisc_table(struct mlx5e_flow_steering *fs)
 void mlx5e_fs_set_rx_mode_work(struct mlx5e_flow_steering *fs,
 			       struct net_device *netdev)
 {
+	struct mlx5e_priv *priv = netdev_priv(netdev);
 	struct mlx5e_l2_table *ea = &fs->l2;
 
+	if (mlx5e_is_uplink_rep(priv)) {
+		mlx5e_handle_netdev_addr(fs, netdev);
+		goto update_vport_context;
+	}
+
 	bool rx_mode_enable  = fs->state_destroy;
 	bool promisc_enabled   = rx_mode_enable && (netdev->flags & IFF_PROMISC);
 	bool allmulti_enabled  = rx_mode_enable && (netdev->flags & IFF_ALLMULTI);
@@ -864,6 +870,7 @@ void mlx5e_fs_set_rx_mode_work(struct mlx5e_flow_steering *fs,
 	ea->allmulti_enabled  = allmulti_enabled;
 	ea->broadcast_enabled = broadcast_enabled;
 
+update_vport_context:
 	mlx5e_vport_context_update(fs, netdev);
 }
 
@@ -984,6 +991,9 @@ static int mlx5e_add_l2_flow_rule(struct mlx5e_flow_steering *fs,
 	u8 *mc_dmac;
 	u8 *mv_dmac;
 
+	if (!ft)
+		return -EINVAL;
+
 	spec = kvzalloc_obj(*spec);
 	if (!spec)
 		return -ENOMEM;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index f7009da94f0b..3eebdf402129 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -4102,9 +4102,6 @@ mlx5e_get_stats(struct net_device *dev, struct rtnl_link_stats64 *stats)
 
 static void mlx5e_nic_set_rx_mode(struct mlx5e_priv *priv)
 {
-	if (mlx5e_is_uplink_rep(priv))
-		return; /* no rx mode for uplink rep */
-
 	queue_work(priv->wq, &priv->set_rx_mode_work);
 }
 
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
index 1db4ecb2356f..8992f0f7a870 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
@@ -1369,6 +1369,8 @@ static void mlx5e_uplink_rep_disable(struct mlx5e_priv *priv)
 	netdev_unlock(priv->netdev);
 	rtnl_unlock();
 
+	/* clean-up uplink's mpfs mac table */
+	queue_work(priv->wq, &priv->set_rx_mode_work);
 	mlx5e_rep_bridge_cleanup(priv);
 	mlx5e_dcbnl_delete_app(priv);
 	mlx5_notifier_unregister(mdev, &priv->events_nb);

base-commit: 52ede1bce557c66309f41ac29dd190be23ca9129
-- 
2.44.0

Re: [PATCH net-next] net/mlx5e: Enable mac forwarding on uplink representor

[Jakub Kicinski]

On Tue, 10 Mar 2026 12:48:41 +0200 Tariq Toukan wrote:
> This small patch enables mac forwarding to MPFs via uplink representor,

"mac forwarding to MPF via uplink representor"
Can't wrap my head around this "via". Could you explain this better?
Perhaps some tool can spit out a little diagram to make the flow clear?

Re: [PATCH net-next] net/mlx5e: Enable mac forwarding on uplink representor

[Saeed Mahameed]

On 11 Mar 20:33, Jakub Kicinski wrote:
>On Tue, 10 Mar 2026 12:48:41 +0200 Tariq Toukan wrote:
>> This small patch enables mac forwarding to MPFs via uplink representor,
>
>"mac forwarding to MPF via uplink representor"
>Can't wrap my head around this "via". Could you explain this better?
>Perhaps some tool can spit out a little diagram to make the flow clear?
>

Mac forwarding in the sense of linux bridge mac forwarding mechanism which
requires set_rx_mode ndo to be implemented. 

Linux-bridge --> mlx5-uplink-rep --> set_rx_mode --> set up mac in HW.

Thanks,
Saeed.

Re: [PATCH net-next] net/mlx5e: Enable mac forwarding on uplink representor

[Jakub Kicinski]

On Tue, 17 Mar 2026 11:12:15 -0700 Saeed Mahameed wrote:
> On 11 Mar 20:33, Jakub Kicinski wrote:
> >On Tue, 10 Mar 2026 12:48:41 +0200 Tariq Toukan wrote:  
> >> This small patch enables mac forwarding to MPFs via uplink representor,  
> >
> >"mac forwarding to MPF via uplink representor"
> >Can't wrap my head around this "via". Could you explain this better?
> >Perhaps some tool can spit out a little diagram to make the flow clear?
> >  
> 
> Mac forwarding in the sense of linux bridge mac forwarding mechanism which
> requires set_rx_mode ndo to be implemented. 
> 
> Linux-bridge --> mlx5-uplink-rep --> set_rx_mode --> set up mac in HW.

And the actual forwarding happens in SW bridge? This is just to
configure the Rx filter not to discard on Rx?

Re: [PATCH net-next] net/mlx5e: Enable mac forwarding on uplink representor

[Saeed Mahameed]

On 17 Mar 14:36, Jakub Kicinski wrote:
>On Tue, 17 Mar 2026 11:12:15 -0700 Saeed Mahameed wrote:
>> On 11 Mar 20:33, Jakub Kicinski wrote:
>> >On Tue, 10 Mar 2026 12:48:41 +0200 Tariq Toukan wrote:
>> >> This small patch enables mac forwarding to MPFs via uplink representor,
>> >
>> >"mac forwarding to MPF via uplink representor"
>> >Can't wrap my head around this "via". Could you explain this better?
>> >Perhaps some tool can spit out a little diagram to make the flow clear?
>> >
>>
>> Mac forwarding in the sense of linux bridge mac forwarding mechanism which
>> requires set_rx_mode ndo to be implemented.
>>
>> Linux-bridge --> mlx5-uplink-rep --> set_rx_mode --> set up mac in HW.
>
>And the actual forwarding happens in SW bridge? This is just to
>configure the Rx filter not to discard on Rx?

Yes Forwarding happens on the SW bridge, just to register the mac so it
won't get dropped.

Re: [PATCH net-next] net/mlx5e: Enable mac forwarding on uplink representor

[Jakub Kicinski]

On Wed, 18 Mar 2026 12:10:37 -0700 Saeed Mahameed wrote:
> >> Mac forwarding in the sense of linux bridge mac forwarding mechanism which
> >> requires set_rx_mode ndo to be implemented.
> >>
> >> Linux-bridge --> mlx5-uplink-rep --> set_rx_mode --> set up mac in HW.  
> >
> >And the actual forwarding happens in SW bridge? This is just to
> >configure the Rx filter not to discard on Rx?  
> 
> Yes Forwarding happens on the SW bridge, just to register the mac so it
> won't get dropped.

Ah! Please respin with a better explanation and calling that out? 
I think it's fair for the reader to assume offload when reading
about representors.