I believe that is intended to setup a special char device for doing 'extra' paravirtualization stuff. It's a communication path for doing copy-n-paste buffers and other things. The target_type=virtio ...

Whilst KVM technology has been a regular fixture of mission-critical installations since the 1990s, it’s currently enjoying a ‘second wind’ in other environments via IP-based KVM and growing AV-IT con ...