This apparently wasn't validated against a simple use case, let
alone against things like migration with nested VMs, multliple L2s,
etc...
I did validate the *SREGS2* against all the cases I could (like
migration, EPT/NPT disabled/etc. I even started testing SMM to see
how it affects PDPTRs, and patched seabios to use PAE paging. I still
could have missed something.