On Tue, Jul 07, 2015 at 10:51:45AM +0300, Pavel Fedin wrote:
Hello!
Is there a way where we would make this configurable? Since the "virt" machine types use the MMIO bus by default we should make the PCI bus configurable since not everybody might want to add it actually.
What exactly do you mean? In qemu this is not configurable, it's just there. If you don't want to use it, just don't use it. I see no harm done by adding description of it to domain XML. If you just add a device, and don't specify <address type='pci'>, it will default to <address type='virtio-mmio'> as before. Nothing will change regarding old behavior and backwards compatibility.
The domain XML should contain the devices that are there, not just those the user requested. Backwards compatibility could break if older libvirt refused to start the domain with a pcie root. From looking at the code, that does not seem to be the case. Jan