Re: [PATCH] qemu: auto-assign hostdev interface devices to PCIe

Until recently, an <interface type='network'> would automatically be assigned model "rtl8139" (the default on x86 machinetypes), which in turn would lead to the device being assigned a PCI address on a conventional PCI controller (i.e. a pcie-to-pci-bridge). If the network was a typical Linux host bridge-based network that used an emulated device, this would be appropriate, since the guest actually would get an emulated rtl8139 NIC, and that device is a conventional PCI device. However, if the network being used was a pool of hostdev devices, the guest would get an actual PCIe network device assigned from the host via VFIO; while the interface model in that case is irrelevant for the QEMU commandline to assign the device, the PCI address would have already been assigned prior to runtime, so the address assignment would be done based on the model='rtl8139' - a conventional PCI device. VFIO assignment of a PCIe device to a conventional PCI slot works, but we would rather have these devices in a PCIe slot. Since commit bdb8f2e4186, if <interface type='network'> points to a etwork that is a pool of hostdev devices, the interface model will be _unset_ by default. This patch uses that information when deciding what type of slot to assign to the device: since all hostdev network interfaces are SR-IOV VFs, and *all* SR-IOV network cards are PCIe, it is safe to assume that the VFs are PCIe and we should assign then to a PCIe slot in the guest. Signed-off-by: Laine Stump <laine(a)redhat.com&gt;