On 11/21/2016 07:08 AM, Andrea Bolognani wrote:
If libvirt is using a specific version of pseries, then it already knows that <=2.7 has pci.0 as a root, pcie.0 otherwise. libvirt has a knowledge what QEMU version has what, right?
It doesn't yet, that's the point :)
We *could* add such knowledge to libvirt[1], but *existing* libvirt versions would still not know about it, which means that upgrading QEMU withough upgrading libvirt will result in failure to create new guests.
But that's okay. In general, we try to promise that: old qemu + old libvirt works new qemu + new libvirt works old qemu + new libvirt works new qemu + old libvirt is untested, and may require a libvirt upgrade In other words, as long as you update your stack from top down (libvirt before qemu), you should be fine. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org