You cannot add temporary access to a device for an HVM domU because you cannot dynamically add IDE CD-ROM devices. To make a CD-ROM available for use in an HVM guest, you must add the device before you boot the guest. You can then change the media by using virsh attach-disk.
Note that in an HVM domU, you must use eject in the domU to unlock a removable-media device, such as a CD device, before running the attach-disk subcommand.
The attach-disksubcommand is also used to change the media in a CD drive.
For additional explanation, see the virsh(1M) man page, including “Example 4 Changing a CD in a Solaris HVM Guest Domain.”