The issue seems to be related to exceptions happening in close pages to the fixmap GDT remapping.
The original page fault happen in do_test_wp_bit which set a fixmap entry to test WP flag. If I grow the number of processors supported increasing the distance between the remapped GDT page and the WP test page, the error does not reproduce. I am still looking at the exact distance between repro and no-repro as well as the exact root cause. On Tue, Mar 21, 2017 at 12:23 PM, Thomas Garnier <thgar...@google.com> wrote: > On Tue, Mar 21, 2017 at 12:20 PM, Linus Torvalds > <torva...@linux-foundation.org> wrote: >> >> On Tue, Mar 21, 2017 at 11:16 AM, Thomas Garnier <thgar...@google.com> wrote: >> > This error happens even with Andy TLS fix on 32-bit (GDT is on fixmap >> > but not readonly). I am looking into it. >> > >> > KVM internal error. Suberror: 3 >> > extra data[0]: 80000b0e >> > extra data[1]: 31 >> >> If I read that right, it's extra data[1] 0x31, which >> EXIT_REASON_EPT_MISCONFIG. >> >> I'm not seeing how the A bit in a GDT entry could have anything to do >> with it. I'm assuming it happens even without Andy's patch? > > Correct. > >> >> Linus > > > > > -- > Thomas -- Thomas
