On 07/23/2013 11:17 AM, Daniel P. Berrange wrote: > On Tue, Jul 23, 2013 at 10:44:55AM -0400, Laine Stump wrote: >> This controller is implicit on q35 machinetypes. It provides 31 PCIe >> (*not* PCI) slots as controller 0. >> >> Currently there are no devices that can connect to pcie-root. For a >> usable q35 system, we still need to add a "dmi-to-pci-bridge" pci >> controller, which can connect to pcie-root, and provides pci slots. > Presumably you have another patch which auto-adds a 'dmi-to-pci-bridge' > device when we see a q35 machine, so that auto-PCI address assignment > still works ? If we relied on the user to add that device, then legacy > apps will not work against a QEMU which defaults to q35, since they'll > be adding PCI devices but not know that they need to add this bridge. > Yes, that is in the works, although it may not be finished today. The idea is that when you try to get a slot for a PCI device and you only have pcie slots, we would add a dmi-to-pci-bridge (which provides pci slots that *can't* be hot-plugged) on a pcie slot, then a pci-bridge (which provides hot-pluggable pci slots) on the dmi-to-pci-bridge. After that, all devices that required a hot-pluggable pci slot would automatically be directed to the pci-bridge. (Thinking more about it, I guess I do need to *always* add them even when there are no devices, to allow for hot-plugging later (since we can't hot-plug a dmi-to-pci-bridge or a pci-bridge). Fortunately that makes it simpler). -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list