Re: [PATCHv6 01/16] x86/cpu: Enumerate the LASS feature bits

Borislav Petkov
2025-06-26T15:19:44Z

On Mon, Jun 23, 2025 at 04:42:41PM +0300, Kirill A. Shutemov wrote:
> Due to SLAM, we decided to postpone LAM enabling, until LASS is landed.
>
> I am not sure if we want to add static
> /sys/devices/system/cpu/vulnerabilities/slam with "Mitigation: LASS".
>
> There might be other yet-to-be-discovered speculative attacks that LASS
> mitigates. Security features have to visible to userspace independently of
> known vulnerabilities.

... and the fact that a vuln is being mitigated by stating that in
/sys/devices/system/cpu/vulnerabilities/ needs to happen too.

I'm not talking about LAM enablement - I'm talking about adding a

SPECTRE_V1_MITIGATION_LASS

and setting that when X86_FEATURE_LASS is set so that luserspace gets told
that

"Spectre V1 : Mitigation: LASS"

or so.

Makes more sense?

--
Regards/Gruss,
Boris.