On Fri, 2016-10-14 at 16:54 +0200, Ján Tomko wrote:
Also, would it be possible to make this feature of leaving free hot-pluggable slots opt-in? E.g. a <controller model='pcie-root-port'> without an index would be considered a port where we should not put devices with auto-assigned addresses. (This might actually be more ugly than the proposed solution, or the 'freeHotplugSlots' attribute, but I dislike implicit device additions after having model='none' memballoon and usb controller)
If we can find a way to make it opt-in without it turning out incredibly ugly (eg. 'freeHotplugSlots' or similar paramers) or requiring too much knowledge from the users / management applications (eg. "you have x legacy PCI devices and y PCI Express devices, that means adding x + y + z + 3 pcie-root-ports before passing the XML to libvirt") I'm all for that. So far we haven't been able to come up with anything like that, though :) I think the current proposal is fairly okay because it allows for easy opt-out, and if we reduce the number of extra ports to just one as per your comments I don't think people will care at all. As far as I'm concerned, that's a very good balance; it's certainly better than the status quo of adding a completely useless dmi-to-pci-bridge + pci-bridge combination to every single q35 guest. -- Andrea Bolognani / Red Hat / Virtualization