Re: PCID review?

[Kees Cook <keescook@chromium.org>]

On Tue, Feb 7, 2017 at 10:56 AM, Andy Lutomirski <luto@kernel.org> wrote:
> Quite a few people have expressed interest in enabling PCID on (x86)
> Linux.  Here's the code:
>
> https://git.kernel.org/cgit/linux/kernel/git/luto/linux.git/log/?h=x86/pcid
>
> The main hold-up is that the code needs to be reviewed very carefully.
> It's quite subtle.  In particular, "x86/mm: Try to preserve old TLB
> entries using PCID" ought to be looked at carefully to make sure the
> locking is right, but there are plenty of other ways this this could
> all break.
>
> Anyone want to take a look or maybe scare up some other reviewers?
> (Kees, you seemed *really* excited about getting this in.)

Yeah, I'd really like to build on it to gain SMAP emulation, though
both implementing that and reviewing the existing series is outside my
current skills (well, okay, you could add "Reviewed-by:"-me to the
first 3 patches ;)). I don't know Intel guts well enough to
meaningfully do anything on the others. :)

I've added Thomas Garnier to CC, in case this is something he might be
able to assist with.

Does this need benchmarking or other testing? Perhaps bring it to the
kernel-hardening list for that?

Also, what's needed to gain SMAP emulation?

-Kees

-- 
Kees Cook
Pixel Security

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