On Fri 2018-02-09 17:47:43, Andy Lutomirski wrote: > On Fri, Feb 9, 2018 at 9:25 AM, Joerg Roedel <joro@xxxxxxxxxx> wrote: > > 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
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