Subject: Re: [PATCH net-next] rtnetlink: Allow setting IFLA_PERM_ADDRESS at device creation time

From: Jakub Kicinski <[email-masked]>
Date: Mon, 17 Feb 2025 09:51:50 -0800

On Thu, 13 Feb 2025 17:13:53 +0100 Toke Høiland-Jørgensen wrote:
> Jakub Kicinski <[email-masked]> writes:
> 
> > On Thu, 13 Feb 2025 14:45:22 +0100 Toke Høiland-Jørgensen wrote:  
> >> Eric suggested[0] allowing user-settable values for dev->perm_addr at
> >> device creation time, instead of mucking about with netdevsim to get a
> >> virtual device with a permanent address set.  
> >
> > I vote no. Complicating the core so that its easier for someone 
> > to write a unit test is the wrong engineering trade off.
> > Use a VM or netdevsim, that's what they are for.  
> 
> Hmm, and you don't see any value in being able to specify a permanent
> identifier for virtual devices? That bit was not just motivated
> reasoning on my part... :)

I can't think of any :( Specifying an address is already possible.
Permanent address is a property of the hardware platform.
Virtual devices OTOH are primarily used by containers, 
which are ephemeral by design. At least that's my mental model.