[libvirt-users] usb passtrough stuck to a given

So I have an entry for a USB device ( ID 051d:0002, UPS) I want to use with a given vm client. In that vm client's config file I added something like this: <hostdev mode='subsystem' type='usb' managed='yes'> <source> <vendor id='0x051d'/> <product id='0x0002'/> </source> </hostdev> And that worked fine for a while. Now I moved the vm host, and then put the cable to the UPS on an available USB port Bus 002 Device 006: ID 051d:0002 American Power Conversion Uninterruptible Power and tried to restart the client... and got the following message: error: internal error Did not find USB device 51d:2 bus:2 device:3 Er, why should it care about which bus and device this is? I thought my config would mean it would look for the device that matched the ID in the config no matter where it was. How did it learn and memorized what I guess is the old location?