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No need for a common kvm_arch function etc. > > > > IDK, I think Marc and Oliver are right it makes sense to have it, I > > just don't really see how a VMM would make use of it.. > > > > Jason > > Right, it was also pointed out that the VMM could make use of it > for early termination during VM migration between incompatible > systems (i.e. across systems with and without FWB and CACHE DIC). In practice it isn't that useful. This is all linked to VFIO so the receiving VMM and system must already have VFIO load and must already have the VMM told to use the coherent VFIO mapping. It would be a serious misconfiguration to setup a VMM as a migration target when the configuration can't even boot normally - because memslot creation would fail for the VFIO coherent memory. Regardless, in such a case the memslot creation should fail and the migration will abort. Jason