Re: [libvirt-users] What to configure for a guest with 2.2. kernel ...

This is a question for virt-manager, which is a package built on top of libvirt, and maintained on the virt-tools-list(a)redhat.com [cc'd, in case someone wants to add more details to this thread]. That said, my understanding is that the only use virt-manager makes of these designations is knowing in advance whether your guest is able to support virtio out of the box (newer Linux builds do, older ones don't), to know whether to expose the disk image to the guest as virtio (faster) or as scsi (slower, but portable to more guests). Choosing other/generic is always safe, if you later want to tweak things to see if virtio was supported after all.