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SubjectRe: [RFC PATCH v2 6/6] x86/entry/pti: don't switch PGD on when pti_disable is set

* Andy Lutomirski <luto@amacapital.net> wrote:

> > Oh, and yes, I think the npti flag should also break ptrace(). I do agree with
> > Andy that it's a "capability", although I do not think it should actually be
> > implemented as one.
>
> For all that Linux capabilities are crap, nopti walks like one and quacks like
> one. It needs to affect ptrace() permissions, it needs a way to disable it
> systemwide, it needs LSM integration, etc. Using CAP_DISABLE_PTI gives us all
> of this without tons of churn, auditing, and a whole new configuration thingy
> for each LSM. And I avoids permanently polluting ptrace checks, the LSM
> interface, etc for what is, essentially, a performance hack to work around a
> blatant error in the design of some CPUs.
>
> Plus, with ambient caps, we already did the nasty part of the with and finished
> all the relevant bikeshedding.
>
> So I'd rather just hold my nose and add the new capability bit.

Those all seem pretty valid arguments to me.

Thanks,

Ingo

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