On Wed, Jun 10, 2009 at 05:46:03PM +0100, Paul Brook wrote: > > > If you can't create an identical machine from scratch then I don't > > > consider snapshot/migration to be a useful feature. i.e. as soon as you > > > shutdown and restart the guest it is liable to break anyway. > > > > Why is liable to break? > > A VM booted on an old version of qemu and migrated to a new version will > behave differently to a the same VM booted on a new version of qemu.
It will behave identically. That's what the patch does: discover how did the device behave on old qemu, and make it behave the same way on new qemu. > I hope I don't need to explain why this is bad. > > As previously discussed, any guest visible changes are liable to break a > guest > OS, particularly guests like Windows which deliberately break when run on > "different" hardware. Personally I don't particularly care, but if we support > live migration we also need to support "cold" migration - i.e. shutdown and > restart. > > >So once you load and image with MSIX capability off, > >it will stay off across guest restarts. > > I'm assuming guest restart includes restarting qemu. > > Paul If you restart qemu, and load an image, what we should do is look at the image and behave in a way consistent with how the qemu that created the image behaved. If you load an image, you switch to a VM, and should be consistent with the VM you just loaded. And we do not need a flag or a machine description file to tell us this. -- MST -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
