Re: [PATCH v10 01/15] x86/cpu: Enumerate the LASS feature bits

Sohil Mehta
2025-10-07T20:49:25Z

On 10/7/2025 11:19 AM, Edgecombe, Rick P wrote:
>> LASS provides the same mode-based protections as paging but without
>> traversing the paging structures. Because the protections are enforced
>> pre-paging, an attacker will not be able to derive paging-based timing
>
> Nit: pre-page walk maybe? Otherwise it could sound like before paging is enabled
> during boot.
>

How about: ... protections are enforced prior to page walks, an ...

>>
>> +config X86_DISABLED_FEATURE_LASS
>> + def_bool y
>> + depends on X86_32
>> +
>
> All the other ones in the file are !X86_64. Why do this one X86_32?
>

The double negation (DISABLED and !X86_64) was harder to follow when
this was initially posted.

https://lore.kernel.org/lkml/73796800-819b-4433-b0ef-db852336d7a4@zytor.com/
https://lore.kernel.org/lkml/756e93a2-7e42-4323-ae21-a5437e71148e@infradead.org/

I don't have a strong preference. I guess the inconsistency makes it
confusing as well. Will change it back to !X86_64 unless Xin objects.