On Fri, Feb 06, 2026 at 10:27:39AM +0100, Peter Krempa wrote: > On Mon, Jan 12, 2026 at 15:49:16 +0100, Andrea Bolognani via Devel wrote: > > The current behavior is to error out, but that's not very helpful. > > Automatically add the necessary USB controller instead. > > IMO this creates the same situation we're in currently with the addition > of SCSI controllers. We add 'lsilogic' as controller if you don't have > any which is sub-optimal, but it's the default and the behaviour we've > standardized on thus we can't really change it. > > The auto-added USB controller will be likely sub-optimal either now or > in the future. While it seems helpful to add it it can create headaches. > > To me it seems that the users simply should add the controller manually > if the platform doesn't have one.
In many cases users will want to add the controller manually even for architectures that do provide it by default, specifically because the chosen model might be suboptimal. This is exactly what virt-manager already does, both for SCSI and USB controllers. The fact that the behavior of automatically adding a controller when a device that needs it is present in the domain XML is already well established for SCSI and others is IMO good motivation for doing the same with USB controllers, even if there are some known potential pitfalls with the approach. -- Andrea Bolognani / Red Hat / Virtualization
