On Apr 28, 2014, at 1:41 PM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > Il 17/04/2014 00:04, Marcelo Tosatti ha scritto: >>>>> > >> @@ -3550,9 +3550,9 @@ static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu, >>>>> > >> break; >>>>> > >> case PT64_ROOT_LEVEL: >>>>> > >> context->rsvd_bits_mask[0][3] = exb_bit_rsvd | >>>>> > >> - rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8); >>>>> > >> + rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 7); >>>>> > >> context->rsvd_bits_mask[0][2] = exb_bit_rsvd | >>>>> > >> - rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8); >>>>> > >> + rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 7); >>>> > > >>>> > > Bit 7 is not reserved either, for the PDPTE (its PageSize bit). >>>> > > >>> > >>> > In long mode (IA-32e), bit 7 is definitely reserved. > > It's always reserved for PML4E (rsvd_bits_mask[x][3]), while for PDPTEs it is not reserved if you have 1GB pages. > >> There is a separate reserved mask for PS=1, nevermind. >> > > Yeah, but the situation for IA32e rsvd_bits_mask[0][2] is exactly the same as for PAE rsvd_bits_mask[0][1], and we're not marking the bit as reserved there. > > The right thing to do is to add rsvd_bits(7, 7) to both rsvd_bits_mask[0][2] and rsvd_bits_mask[1][2], if 1GB pages are not supported. > > As written, the patch has no effect on PDPTEs because rsvd_bits_mask[0][2] is only accessed if bit 7 is zero. > > Nadav, would you mind preparing a follow-up? Also, how did you find these issues and test the fixes? I will create a follow-up as soon as possible. We encountered the issues in a custom testing environment. The fixes were validated using the failing tests, but they cover additional cases which might not have been tested. Regards, Nadav-- 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
