Comment 2 for bug 60273

I'm working with Gutsy and kvm/qemu. I got around this by modifying the permission rule in

/etc/udev/rules.d/40-permissions.rules

I added GROUP="plugdev" so that the USB devices are members of that group:

# USB devices (usbfs replacement)
SUBSYSTEM=="usb_device", MODE="0664", GROUP="plugdev"

Regular user accounts are usually members of that group, which means that qemu/kvm can be run as a regular user and access the USB devices:

$ sudo /etc/init.d/udev reload
$ sudo find /dev/bus/usb -exec ls -l {} \; | grep plugdev
crw-rw-r-- 1 root plugdev 189, 141 2007-10-31 18:58 014
crw-rw-r-- 1 root plugdev 189, 142 2007-10-31 18:58 015
crw-rw-r-- 1 root plugdev 189, 143 2007-10-31 19:29 016
crw-rw-r-- 1 root plugdev 189, 144 2007-10-31 19:34 017
crw-rw-r-- 1 root plugdev 189, 145 2007-10-31 18:58 018
crw-rw-r-- 1 root plugdev 189, 146 2007-10-31 18:58 019
crw-rw-r-- 1 root plugdev 189, 146 2007-10-31 18:58 /dev/bus/usb/002/019
crw-rw-r-- 1 root plugdev 189, 145 2007-10-31 18:58 /dev/bus/usb/002/018
crw-rw-r-- 1 root plugdev 189, 144 2007-10-31 19:34 /dev/bus/usb/002/017
crw-rw-r-- 1 root plugdev 189, 143 2007-10-31 19:29 /dev/bus/usb/002/016
crw-rw-r-- 1 root plugdev 189, 142 2007-10-31 18:58 /dev/bus/usb/002/015
crw-rw-r-- 1 root plugdev 189, 141 2007-10-31 18:58 /dev/bus/usb/002/014

A group could be created specifically for qemu/kvm but using plugdev makes more sense since it is there to provide support for hot-plugged devices.