Re: [PATCH v5 1/3] selftests/lam: Move cpu_has_la57() to use cpuinfo flag

[Dave Hansen]

On 1/24/25 12:17, Maciej Wieczor-Retman wrote:
>> Could you poke around and see if there is any existing ABI that we can
>> use to query LA57 support? Maybe one of the things KVM exports, or some
>> TASK_SIZE_MAX comparisons?
> Sure, I'll try to find some other way.
> 
> My previous tactic was to munmap() a high address and see if it works. Does that
> sound okay in case there isn't anything else would indicate la57 to userspace
> reliably?

Yeah, I think that's fine. I can't think of any obvious horrible
pitfalls. All I'd ask is that you spend 20 minutes grepping for things
that are conditional on X86_FEATURE_LA57 and see if there's anything
else that's a good candidate.