On Wed, Oct 20, 2021 at 2:31 PM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>
> On 20/10/21 23:18, Jim Mattson wrote:
> >>>> - vmcs_write(GUEST_LIMIT_TR, tss_descr.limit);
> >>>> + vmcs_write(GUEST_LIMIT_TR, 0x67);
> >>> Isn't the limit still set to 0xFFFF in {cstart,cstart64}.S? And
> >>> doesn't the VMware backdoor test assume there's room for an I/O
> >>> permission bitmap?
> >>>
> >> Yes, but this is just for L2. The host TR limit is restored to 0x67 on
> >> every vmexit, and it seemed weird to run L1 and L2 with different limits.
> > Perhaps you could change the limits in the GDT entries to match?
>
> So keep it 0x67 and adjust it to the size of the IOPM in the VMware
> backdoor test?
Right. That would seem to achieve the greatest consistency.
