Re: [libvirt-users] [libvirt] Why virsh domxml-to-native qemu-argv changes PCI slot number

On Thu, 2019-04-18 at 15:29 +0100, Daniel P. Berrangé wrote: > On Thu, Apr 18, 2019 at 04:23:05PM +0200, Andrea Bolognani wrote: > > qemuDomainAssignAddresses() is supposed to make sure that any address > > configured explicitly by the user (or previously by libvirt) is > > preserved, and it's doing that correctly when it's called from inside > > qemuDomainDefAssignAddresses(); however, for some reason, by the time > > we call it again in qemuProcessPrepareDomain() the PCI address for > > the network interface is no longer set, and so a fresh one gets > > assigned instead. > > > > I'll investigate further and get back to you. > > It is a bug in qemuConnectDomainXMLToNative. You'll see we replace > the original type=bridge NIC with a type=ethernet, except we fail > to copy the address info & probably other properties too. Yeah, I figured that out after digging a bit more :) I'm not quite sure how to fix it properly, though. Adding yet more properties to the list of those we record before calling virDomainNetDefClear() and restore afterwards would be a stop-gap measure at best; limiting ourselves to merely changing net->type, on the other hand, though it seems to work from a quick test, will likely lead to hitting other corner cases. Formatting the XML, replacing the type attribute and parsing it back perhaps? Other, hopefully better, ideas?