Запускаю так:
qemu-kvm windows_xp -net nic -net user -usb -usbdevice host:067b:2303
husb: open /dev/bus/usb/001/003: Permission denied
husb: open /dev/bus/usb/001/003: Permission denied
husb: open /dev/bus/usb/001/003: Permission denied
ls -al /dev/bus/usb/001/*
crw-rw-r-- 1 root root 189, 0 окт. 5 19:06 /dev/bus/usb/001/001
crw-rw-r-- 1 root root 189, 1 окт. 5 19:06 /dev/bus/usb/001/002
crw-rw-r-- 1 root root 189, 3 окт. 5 19:06 /dev/bus/usb/001/004
crw-rw-r-- 1 root root 189, 9 окт. 5 20:08 /dev/bus/usb/001/010