Re: [libvirt] [PATCH/RFC]: file backed usb massstorage

On Wed, Jul 30, 2008 at 09:47:00AM +0100, Daniel P. Berrange wrote: > On Mon, Jul 28, 2008 at 11:02:45AM -0400, Guido G?nther wrote: > > On Fri, Jul 25, 2008 at 04:17:30PM -0400, Guido Günther wrote: > > > attached is some basic support for host device passthrough. It enables > > > you to passthrough usb devices in qemu/kvm via: > > On top of the hostdev passthrough (but it's actually totally > > independent) I added usb massstorage backed by a file. Very handy for > > installer testing where the preseed data is on the USB stick and the > > CD/DVD is the installation medium. > > At the moment I'm using a dummy target "usbdisk" so we don't have to > > check for target == NULL in that many places. Once qemu handles it we > > can fill in bus and device address for unplugging. To add a file as usb > > massstorage to the guest you can use: > > > > <disk type='file' device='disk'> > > <source file='/foo/bar/usbmass.img'/> > > <target bus='usb'/> > > </disk> > > The way we do target for other disk types doesn't work so well - others > we typically have a device name, eg hda, sdc, xvdf, etc. For VirtIO we > let people pass in a dummy device name too 'vda', 'vdb', etc. Only some > of the disk buses & guest OS honour these names though - in cases where > they're not honoured, they at most provide a unique key, and allow for > ordering of disks in our XML. USB will be much like SCSI / VirtIO where > the device name in the XML is merely used for ordering, so we should just > allow sda, sdb, etc as the target device name. This will avoid having > to special case the code in the here too much. Acutally I intended to use the target like target="bus:device" once qemu (and others) support this. The would also help on detach. Would you prefer: <target bus='usb' target='sda' bus='0001' id='1234'>