Re: mlx4: no ib device for Ethernet ports without IBoE since v6.6

Re: mlx4: no ib device for Ethernet ports without IBoE since v6.6

[Leon Romanovsky]

On Wed, Oct 14, 2026 at 01:55:48PM +0100, Peter Morrow wrote:
> Hi,
> 
> Since v6.6, mlx4 no longer creates an RDMA device for an Ethernet port
> when the device doesn't advertise IBoE. On Azure, ConnectX-3 VFs are in
> that state, so DPDK's mlx4 PMD can no longer open them:
> 
>   net_mlx4: cannot access device, is mlx4_ib loaded?
> 
> Petr, thanks for looking at this off-list; as you suggested, I'm reporting
> it here.
> 
> What changed
> ------------
> Commit 7d22b1cb9d84 ("mlx4: Connect the infiniband part to the
> auxiliary bus") creates the "ib" auxiliary device only when
> is_ib_supported() sees an IB port or MLX4_DEV_CAP_FLAG_IBOE. Before it,
> mlx4_ib_add() was called for every device and accepted any IB or
> Ethernet port via mlx4_foreach_ib_transport_port(). An Ethernet port
> without IBoE got a raw-packet-only port. mlx4_port_immutable() still
> has that branch (RDMA_CORE_PORT_RAW_PACKET without RoCE), but nothing
> can reach it now.
> 
> DPDK's mlx4 PMD needs only that: it opens the device through ibverbs
> and creates IBV_QPT_RAW_PACKET QPs. It does not ask for RoCE.
> mlx5_ib handles the equivalent case by creating the device with
> raw_eth_profile when
> RoCE is disabled.

The best approach is probably to add a similar mechanism for mlx4. However, since
that driver is quite old and has limited test coverage, it would be better to
implement something like this:

diff --git a/drivers/net/ethernet/mellanox/mlx4/intf.c b/drivers/net/ethernet/mellanox/mlx4/intf.c
index 82e467c45d23..31860b4abe43 100644
--- a/drivers/net/ethernet/mellanox/mlx4/intf.c
+++ b/drivers/net/ethernet/mellanox/mlx4/intf.c
@@ -43,23 +43,12 @@ static DEFINE_IDA(mlx4_adev_ida);

 static bool is_eth_supported(struct mlx4_dev *dev)
 {
-       for (int port = 1; port <= dev->caps.num_ports; port++)
-               if (dev->caps.port_type[port] == MLX4_PORT_TYPE_ETH)
-                       return true;
-
-       return false;
+       return true;
 }

 static bool is_ib_supported(struct mlx4_dev *dev)
 {
-       for (int port = 1; port <= dev->caps.num_ports; port++)
-               if (dev->caps.port_type[port] == MLX4_PORT_TYPE_IB)
-                       return true;
-
-       if (dev->caps.flags & MLX4_DEV_CAP_FLAG_IBOE)
-               return true;
-
-       return false;
+       return true;
 }

 static const struct mlx4_adev_device {

Can you please send proper patch?

Thanks