Speculating memory reference reads across security boundaries is not a trade-off (except if you can prove that you will not further act on them in any data depe

Speculating memory reference reads across security boundaries is not a trade-off (except if you can prove that you will not further act on them in any data dependant way that is observable). That's mostly common sense. Spectre does not need that -- but OTOH is more difficult to exploit; it is in a whole different category. There is a reason they have different names.