On Fri 2018-02-09 17:47:43, Andy Lutomirski wrote:

On Fri, Feb 9, 2018 at 9:25 AM, Joerg Roedel [off-list ref] wrote:

quoted

Hi,

here is the second version of my PTI implementation for
x86_32, based on tip/x86-pti-for-linus. It took a lot longer
than I had hoped, but there have been a number of obstacles
on the way. It also isn't the small patch-set anymore that v1
was, but compared to it this one actually works :)

One thing worth noting is that performance of this whole series is
going to be abysmal due to the complete lack of 32-bit PCID.  Maybe
any kernel built with this option set that runs on a CPU that has
the

What kind of slowdown are we talking about here?

PCID bit set in CPUID should print a big fat warning like "WARNING:
you are using 32-bit PTI on a 64-bit PCID-capable CPU.  Your
performance will increase dramatically if you switch to a 64-bit
kernel."

Hardware supports PCID even on 32-bit kernels, no?

									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html