Re: [PATCH v2] selftests/x86: Add a test for LASS enforcement

[H. Peter Anvin]

On 2026-10-13 12:51, Sohil Mehta wrote:
> 
> I had it in v1 of this patch. It seemed excessive to do specifically for
> LASS:
> https://lore.kernel.org/lkml/20260806011536.4172258-8-sohil.mehta@xxxxxxxxx/
> 

"Specificially for LASS" is the problem here.

This goes under the "do it generally, do it right, do it once." Librarize it.

> I agree, adding them as generic selftest helpers may be useful. But,
> /proc/cpuinfo has been unreliable in general. It is currently buggy for
> some features with Kconfig options. See:
> 
> https://lore.kernel.org/lkml/f6f113b46199d996c4f81fc89858c2f484256418.1774623092.git.m.wieczorretman@xxxxx/

> Also, (I think) we have been generally discouraging folks to add more
> bits there. So, I don't know if creating these library routines is
> useful right now. IIUC, Boris said that the CPUID rework would make some
> of cpuinfo stuff moot.
> 
> https://lore.kernel.org/lkml/20260331140216.GDacvT6IPW1gf003z-@fat_crate.local/

> Thoughts?

This is a great example of why these interfaces *are* useful and why they
*should* be fixed.

	-hpa