On Wed, Jun 23, 2021, Paolo Bonzini wrote: > On 23/06/21 18:17, Sean Christopherson wrote: > > > What the commit message doesn't say is, did we miss this > > > opportunity all along, or has there been a change since commit > > > 47c42e6b4192 ("KVM: x86: fix handling of role.cr4_pae and rename it > > > to 'gpte_size'", 2019-03-28) that allows this? > > > > The code was wrong from the initial "unsync" commit. The 4-byte vs. > > 8-byte check papered over the real bug, which was that the roles were > > not checked for compabitility. I suspect that the bug only > > manisfested as an observable problem when the GPTE sizes mismatched, > > thus the PAE check was added. > > I meant that we really never needed is_ept_sp, and you could have used the > simpler check already at the time you introduced gpte_is_8_bytes. But anyway > I think we're in agreement. Ah, yes, I was too clever :-/