Description of problem:

See bug 663064 for the RHEL6 equivalent.

Add:

# cat /lib/udev/rules.d/42-qemu-usb.rules
ACTION=="add", SUBSYSTEM=="usb", ATTR{product}=="QEMU USB Mouse",    ATTR{serial}=="42", TEST=="power/level", ATTR{power/level}="auto"
ACTION=="add", SUBSYSTEM=="usb", ATTR{product}=="QEMU USB Tablet",   ATTR{serial}=="42", TEST=="power/level", ATTR{power/level}="auto"
ACTION=="add", SUBSYSTEM=="usb", ATTR{product}=="QEMU USB Keyboard", ATTR{serial}=="42", TEST=="power/level", ATTR{power/level}="auto"

This reduces cpu usage noticeably on the qemu/kvm host (8%->1% in my case)

Version-Release number of selected component (if applicable):
udev-182-3.fc17.x86_64