On Tue, Sep 29, 2015 at 1:35 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> 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 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html