Re: [PATCH net-next 0/5] netdevsim: get link via ethtool, set via sysfs

[Íñigo Huguet]

Hi Jakub,

On Sun, May 10, 2026 at 6:52 PM Jakub Kicinski <kuba@xxxxxxxxxx> wrote:
> Could you please explain your motivation? Feels quite trivial,
> so it's not immediately obvious why we need tests.
>

We use netdevsim for some userspace CI testing here at Red Hat. Specifically,
There are some tests that require reacting to carrier changes on a device
matched by permanent MAC address from userspace. As veths don't have a
permanent MAC address, we need netdevsim for this test case.

As you say, it's pretty trivial, but IMHO there's nothing against it, as it
will help to resemble better a typical Ethernet device.

Note: we know that there's no guarantee regarding netdevsim's uAPI and we're
ready to adapt for any change, but the truth is that there's no reasonable
replacement of netdevsim for these kinds of cases where veth is not enough.



-- 
Íñigo Huguet