Hi, >>> 1) Is this difference intentional, or a bug? >> The vga simply goes into the first free slot. That happens to be #2 >> with i440fx and #1 with q35. > > It sounds like it's a safe bet to assume that -vga will put the device > on slot 2 for pc machinetypes and slot 1 for q35, no matter what other > devices there are, since -vga is always initialized first. Correct? Yes. > Do > you see any chance that might change in the future? (e.g. due to some > other new device that needs to be initialized even before vga) Highly unlikely. Also libvirt will switch over to use -device for vga cards, which will make this a moot point. >>> 3) Does the qxl multihead support really require that the device be at >>> slot 2 (as stated in the above bugzilla commend)? Or is that just a >>> misunderstanding/overstatement? >> It's not required at all. The problem is that on older qemu versions >> (pre-memory-api basically) it was impossible to create functional vga >> devices via -device due to an initialization order issue. Which implies >> you have to use -vga instead, which in turn implies the vga ends up in >> slot #2. On i440fx, but q35 didn't exist yet back then ;) > > Are you saying that it's still required to use -vga instead of -device > qxl-vga for pc machinetype? Or that it was needed at one time, but that > is no longer the case? If the latter, is there a reliable way to make > the decision whether or not we need to use -vga? libvirt has started using -device for vga cards, to be able to place them in any pci slot. IIRC it's used for qemu 1.1+ or 1.2+. That works fine for all vga cards except qxl. The bug which broke it for qxl will be fixed in 1.6 (and probably 1.5.3 too). cheers, Gerd -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list