Re: PCID review?

[Thomas Garnier <thgarnie@google.com>]

On Tue, Feb 7, 2017 at 11:11 AM, Kees Cook <keescook@chromium.org> wrote:
> 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.

It would be great to add but I have limited cycles and definitely
lacking knowledge on that front.

>
> 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



-- 
Thomas

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