ubuntu virtualbox guest 1920x1080 resolution not available code example
Example: ubuntu virtualbox 1920x1080
xrandr --newmode "1920x1080" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync
xrandr --addmode Virtual1 1920x1080
xrandr --output Virtual1 --mode 1920x1080