qemu/docs/system/keys.rst.inc

During the graphical emulation, you can use special key combinations from
the following table to change modes. By default the modifier is Ctrl-Alt
(used in the table below) which can be changed with ``-display`` suboption
``mod=`` where appropriate. For example, ``-display sdl,
grab-mod=lshift-lctrl-lalt`` changes the modifier key to Ctrl-Alt-Shift,
while ``-display sdl,grab-mod=rctrl`` changes it to the right Ctrl key.

Ctrl-Alt-f
   Toggle full screen

Ctrl-Alt-+
   Enlarge the screen

Ctrl-Alt\--
   Shrink the screen

Ctrl-Alt-u
   Restore the screen's un-scaled dimensions

Ctrl-Alt-n
   Switch to virtual console 'n'. Standard console mappings are:

   *1*
      Target system display

   *2*
      Monitor

   *3*
      Serial port

Ctrl-Alt-g
   Toggle mouse and keyboard grab.

In the virtual consoles, you can use Ctrl-Up, Ctrl-Down, Ctrl-PageUp and
Ctrl-PageDown to move in the back log.