Re: [PATCH RFC 3/4] x86/pti: don't mark the user PGD with _PAGE_NX.

From: Ingo Molnar
Date: Mon Jan 08 2018 - 13:35:30 EST



* Alan Cox <gnomes@xxxxxxxxxxxxxxxxxxx> wrote:

> > The simplest model is indeed child inheritance tree propagation - plus perhaps the
> > ability for a thread to change its *own* PTI status, which obviously doesn't
> > create any deep "process lookup" or cross-CPU complications.
> >
> > ( Note that here I only mean "simple to implement" - we might decide to not offer
> > the ABI. )
>
> I still think cgroups are the best model for this. In particular it
> naturally fits things like containers, or network facing apps that fork
> helpers.

I think the suggested exec() time inheritance model would naturally also cover
cgroups (without tying the ABI to cgroups) - as containers typically get inherited
from a single binary. A bit like how various personality bits get propagated.

Thanks,

Ingo