Comment 20 for bug 205450

another workaround:

//understand losetup -f and -a
$ sudo losetup -f
$ sudo losetup -a

//actually do the mount and check that it worked and which device it picked
$ sudo losetup `sudo losetup -f` <iso_file>
$ sudo losetup -a

//then use phy:/dev/loop<num> in your xen config file

I wouldn't recommend this for disk partition, use tap:aio: instead.

But for cdrom image files, it is a good workaround.

Also, remember that file: is deprecated due to the problems with loopback devices
which is what this workaround uses, which is why you should only use it for iso (read-only) files.