On Fri, Sep 10, 2021, Peter Gonda wrote: > > Do we really want to bury this under KVM_CAP? Even KVM_CAP_VM_COPY_ENC_CONTEXT_FROM > > is a bit of a stretch, but at least that's a one-way "enabling", whereas this > > migration routine should be able to handle multiple migrations, e.g. migrate A->B > > and B->A. Peeking at your selftest, it should be fairly easy to add in this edge > > case. > > > > This is probably a Paolo question, I've no idea if there's a desire to expand > > KVM_CAP versus adding a new ioctl(). > > Thanks for the review Sean. I put this under KVM_CAP as you suggested > following the idea of svm_vm_copy_asid_from. Paolo or anyone else have > thoughts here? It doesn't really matter to me. Ah, sorry :-/ I obviously don't have a strong preference either. > > > +Architectures: x86 SEV enabled > > > +Type: vm > > > +Parameters: args[0] is the fd of the source vm > > > +Returns: 0 on success > > > > It'd be helpful to provide a brief description of the error cases. Looks like > > -EINVAL is the only possible error? > > > > > +This capability enables userspace to migrate the encryption context > > > > I would prefer to scope this beyond "encryption context". Even for SEV, it > > copies more than just the "context", which was an abstraction of SEV's ASID, > > e.g. this also hands off the set of encrypted memory regions. Looking toward > > the future, if TDX wants to support this it's going to need to hand over a ton > > of stuff, e.g. S-EPT tables. > > > > Not sure on a name, maybe MIGRATE_PROTECTED_VM_FROM? > > Protected VM sounds reasonable. I was using 'context' here to mean all > metadata related to a CoCo VM as with the > KVM_CAP_VM_COPY_ENC_CONTEXT_FROM. Is it worth diverging naming here? Yes, as they are two similar but slightly different things, IMO we want to diverge so that it's obvious they operate on different data.
