Re: [PATCH v14 00/13] Introduce support for guest CET feature

[Paolo Bonzini]

On 28/01/21 19:04, Sean Christopherson wrote:
> On Thu, Jan 28, 2021, Paolo Bonzini wrote:
> > On 06/11/20 02:16, Yang Weijiang wrote:
> > > Control-flow Enforcement Technology (CET) provides protection against
> > > Return/Jump-Oriented Programming (ROP/JOP) attack. There're two CET
> > > sub-features: Shadow Stack (SHSTK) and Indirect Branch Tracking (IBT).
> > > SHSTK is to prevent ROP programming and IBT is to prevent JOP programming.
>
> ...
>
> > I reviewed the patch and it is mostly okay.  However, if I understand it
> > correctly, it will not do anything until host support materializes, because
> > otherwise XSS will be 0.
>
> IIRC, it won't even compile due to the X86_FEATURE_SHSTK and X86_FEATURE_IBT
> dependencies.

Of course, but if that was the only issue I would sort it out with Boris 
as usual.  OTOH if it is dead code I won't push it to Linus.

Paolo

> > If this is the case, I plan to apply locally v15 and hold on it until the
> > host code is committed.
> >
> > Paolo