Sets the format for a given cdrom drive. This directive exists to do some special magic for cd drive formats 'ahci' and 'usb2' (see virttest/qemu_vm.py for more information).
Currently used options in Avocado-VT are: ahci and usb2.
Example:
variants: - usb.cdrom: cd_format = usb2
No other documentation currently references this configuration key.