Re: [PATCH net-next] net/mlx5: Add MLX5_VXLAN config option

[Marc Harvey]

On Tue, May 5, 2026 at 1:21 AM Gal Pressman <gal@xxxxxxxxxx> wrote:
>
> Hi Marc,
>
> On 05/05/2026 4:10, Jakub Kicinski wrote:
> >
> > Sorry, I don't know mlx5 very well. Sounds like you have to talk
> > to nVidia or/and run some experiments. The current patch is a no-go.
> >
>
> The hardware offloads 4789 by default, hence the
> UDP_TUNNEL_NIC_INFO_STATIC_IANA_VXLAN, you cannot simply remove it.
>
> Have you tried disabling tx-udp_tnl-segmentation through ethtool?

Thanks for the responses.

Gal, by "the hardware offloads 4789 by default," does that mean the
hardware offloads 4789 even without an explicit command from the
driver? I ask because mlx5 does send a command to offload 4789, but
perhaps this command is redundant and only for bookkeeping purposes.

I haven't tried changing the offload related ethtool parameters, and I
will, but I suspect it won't help in this specific case since the
perceived regression involved non-tunneled traffic.

If the hardware indeed offloads 4789 autonomously, then the perceived
regression we saw might not have been real or related to enabling
vxlan.