Gregory Haskins wrote: >> While KVM will inevitably start requiring newer kernel versions, do we >> really need to do it right now? Perhaps we could add dummy eventfd_* >> functions to the module compat header? Then at least older kernels will >> continue to work with in- kernel APIC disabled. >> >> > > The plan as Avi and I agreed to (IIUC) is to support eventfd via the > extern-compat header. The same could be said for HRT. I don't thing either > one will be particularly pleasant to support in this fashion, but this is how > he wants to do it. (Recall that I had abstracted the HRT in earlier versions > which he requested to be removed, so I didnt bother with the eventfd > interface). I agree that it will keep the kvm core code cleaner instead of > having all these custom abstractions, so I see his point there. I'm just not > looking forward to the compat work ;) > > That being said: Perhaps you just came up with a good compromise. The code > is already structured to support both the old way and the new way. We could > have the in-kernel modes disabled at compile time on older kernels. Thats > probably a much better solution then trying to get HRT and eventfd emulated > on, say, 2.6.9 ;) > > The implication here is that I don't plan on supporting new features via the > old-way. For instance, SMP features would only work with in-kernel > emulation. If we go down this route, it automatically means that older > kernels will not have any other related advanced features, not just the > performance/features currently offered. Perhaps this is acceptable also? > I'm not sure. >
I don't know. I'm less concerned about long term implications than I am with short term ones. My primary concern was having new versions of KVM stop working on older kernels. If SMP requires in-kernel APIC, then provided that UP kernels still work, if someone is sufficiently motivated to get SMP working on older kernels, they can implement the eventfd emulation. Regards, Anthony Liguori > Regards, > -Greg > > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by DB2 Express > Download DB2 Express C - the FREE version of DB2 express and take > control of your XML. No limits. Just data. Click to get it now. > http://sourceforge.net/powerbar/db2/ > _______________________________________________ > kvm-devel mailing list > kvm-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/kvm-devel > > ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
