Re: Candidate Linux ABI for Intel AMX and hypothetical new related features

From: Peter Zijlstra
Date: Mon Mar 29 2021 - 03:28:43 EST


On Sun, Mar 28, 2021 at 01:53:15AM +0100, Thomas Gleixner wrote:
> Though the little devil in my head tells me, that making AMX support
> depend on the CPUID faulting capability might be not the worst thing.
>
> Then we actually enforce CPUID faulting (finally) on CPUs which support
> it, which would be a first step into the right direction simply because
> then random library X has to go to the kernel and ask for it explicitely
> or just shrug and use whatever the kernel is willing to hand out in
> CPUID.
>
> Now take that one step further. When the first part of some user space
> application asks for it, then you can register that with the process and
> make sane decisions for all other requesters which come after it, which
> is an important step into the direction of having a common orchestration
> for this.

I wrote something like that at least one...

https://lore.kernel.org/lkml/20190212164833.GK32494@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/

we just need to make sure AMD implements that before it ships a chip
with AVX512 on.