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All we need is the generalized concept of a folio > with HVO, and a way to move these folios between owners (e.g., > global<->hugetlb, global<->guest_memfd). +1 HVO seems to become a sticking point in these discussions, having a way to make any big folio HVO optimized (and undo it) then put hugetlb on top of that would be a nice refactoring. Jason