Re: [PATCH v3] x86/cpufeatures: Make X86_FEATURE_SHSTK clearcpuid-able

[Mathias Krause <minipli@grsecurity.net>]

On 5/15/26 00:38, Borislav Petkov wrote:
> If you want to disable things, then you need to disable them properly. Like
> turn off CR4 bits in this case or disable dependent features in other cases.
> Or whatever else is needed.
> 
> Whatever you do, it needs to have a use case and be properly done.
> 
> clearcpuid= is simply shooting down X86_FEATURE flags. Not really well thought
> out but a wholesale quick'n'dirty method of toggling feature bits (yah,
> there's the setcpuid= counterpart too). And that's why it should not really
> exist but that ship has sailed...
> 

So a "nocet" for that very use case of disabling CR4.CET, which would
simply disable X86_FEATURE_IBT and X86_FEATURE_SHSTK?

Thanks,
Mathias