On Thu, Mar 08, 2007 at 12:59:30PM +0000, Daniel P. Berrange wrote:
On Thu, Mar 08, 2007 at 04:52:43PM +0900, Masayuki Sunou wrote:
Hi
When domHVM started by virsh create, the information of USB setting is not saved by vish dumpxml. The reason is that USB setting is defined by Xen itself, not virsh.
This patch enables USB device setting information handling on virsh create/virsh dumpxml.
I've been wondering about how we'll represent USB devices in the libvirt XML. The 'usbdevice' attribute in teh XenD SEXPR is just a straight pass-through to QEMU's -usbdevice command line arg. This arg can accept values of the form:
- 'mouse' - 'tablet' - 'disk:file' eg 'disk:/var/lib/xen/images/usbdrive.img' - 'host:bus.addr' eg 'host:01.02' for BUS 01, device 02 - 'host:vendor:product' eg 'host:0324:01a4'
http://fabrice.bellard.free.fr/qemu/qemu-doc.html#SEC34
The patch you've got just puts all this into a single 'usbdevice' attribute on a <usb> element. I see there is also a single empty <usb> tag to identify whether the virtual USB bus is enabled at all. So we have
<usb/> <usb usbdevice='mouse'/> <usb usbdevice='tablet/> <usb usbdevice='disk:/var/lib/xen/images/usbdrive.img'/> <usb usbdevice='host:01.02'/> <usb usbdevice='host:0324:01a4'/>
I'm wondering if we'd be better offnormalizing the attributes somewhat.
<usb bus='1'/> <usb hid='mouse'/> (hid is USB speak for Human Input Device) <usb hid='tablet'/> <usb disk='/var/lib/xen/images/usbdrive.img'/> <usb bus='01' addr='02'/> <usb vendor='0324' product='01a4'/>
Or alternatively, multiplex off a 'type' attribute
<usb type='bus'/> <usb type='mouse'/> <usb type='tablet'/> <usb type='disk' path='/var/lib/xen/images/usbdrive.img'/> <usb type='host' bus='01' addr='02'/> <usb type='host' vendor='0324' product='01a4'>
What do people think ?
That I prefer we first discuss a bit more the format before applying such a patch. I assume the usb description need to go in the <devices> block, right ? I prefer the last version of the 3, you just check for a first attribute and if found derive the processing code according to the value. It's IMHO better than the second structurally speaking, and I really dislike the first because it keeps the structure outside of XML which requires additional parsing and makes things harder. Now thinking out loud a bit, would <usb> need to be a structure, physically it is structured around busses, do we need to reflect that, do we need to make provision for this. Also in what respect is USB specific, I mean <devices> <disk path="..." /> </devices> and <devices> <usb> <disk path="..." /> </usb> </devices> Can we just share parsing or is the fact that a disk hooked on USB bus such a real difference ? Daniel -- Red Hat Virtualization group http://redhat.com/virtualization/ Daniel Veillard | virtualization library http://libvirt.org/ veillard@redhat.com | libxml GNOME XML XSLT toolkit http://xmlsoft.org/ http://veillard.com/ | Rpmfind RPM search engine http://rpmfind.net/