[libvirt] [PATCH/RFC]: hostdev passthrough support take #2

Hi, attached is a second version. Changes are: * s/bus/subsystem/ * support hexadecimal and decimal attributes * introduce device and source elements. I decided to not drop vendor and product id into their own elements since the structure would then become very nested for no good reason. Some examples: <hostdev mode="subsys" type='usb'> <source> <device vendor="0x0204" product="0x6025"/> </source> </hostdev> <hostdev mode="subsys" type='usb'> <source> <address bus="001" device="003"/> </source> </hostdev> Support for <target> will be coming once I got around to adjust qemu/kvm. Cheers, -- Guido