Messages in this thread | | | Date | Tue, 29 Sep 2015 13:50:56 -0400 | Subject | Re: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled | From | Linus Torvalds <> |
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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
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