Sets the VM display type. Of course, only one display type is allowed, and current valid options are: vnc, sdl, spice and nographic.
display = vnc
For VNC displays, the port number is dynamically allocated within the 5900 - 6100 range.
display = sdl
An SDL display does not use a port, but simply behaves as an X client. If you want to send the SDL display to a different X Server, see x11_display?
display = spice
For spice displays, the port number is dynamically allocated within the 8000 - 8100 range.
display = nographic
nographic for qemu/kvm means that the VM will have no graphical display and that serial I/Os will be redirected to console.
No other documentation currently references this configuration key.