lkml.org 
[lkml]   [2015]   [Sep]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled
From
On Tue, Sep 29, 2015 at 1:35 PM, Andy Lutomirski <luto@amacapital.net> wrote:
>
> Does anyone know what happens if you stick a non-accessed segment in
> the GDT, map the GDT RO, and access it?

You should get a #PF, as you guess, but go ahead and test it if you
want to make sure.

We do something very similar for the old Pentium F0 0F bug - we mark
the IDT read-only, which causes the (bogus) locked read of the IDT
entry that the F00F bug resulted in to be caught as a page fault
instead.

Linus


\
 
 \ /
  Last update: 2015-09-29 20:21    [W:0.096 / U:0.260 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site