Display resolution of Fedora 18 virtual machines

Fedora 18 tends to select the maximum display resolution supported by the video card / monitor. This is useful in general, but not optimal for virtual machines; the video output of guests is usually displayed in non-full-screen windows on user desktops. Maximum guest resolution can result in an oversized VM window; scaling it down is possible but not ideal.

The following hints are meant for the case when KMS (Kernel Mode Setting) is in effect in the Fedora 18 guest; eg. on emulated Cirrus hardware. The chosen resolution is 1024x768.

Console

In order to set the resolution of the character mode console, change your UID to root, and specify the video KMS option for the kernel command line, in the /etc/default/grub file:

GRUB_CMDLINE_LINUX_DEFAULT="video=1024x768"

Then run the following command (if the guest was installed on SeaBIOS):

grub2-mkconfig -o /boot/grub2/grub.cfg

If the guest was installed on UEFI/OVMF, run this instead:

grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg

Xorg

The following has been tested under the XFCE spin.

Create the /etc/X11/xorg.conf.d/01-resolution.conf file with the following contents:

Section "Screen"
  Identifier "Default Screen"
  Device     "Default Device"
  Monitor    "Default Monitor"
EndSection

Section "Device"
  Identifier "Default Device"
  Driver     "modesetting"
EndSection

Section "Monitor"
  Identifier "Default Monitor"
  Option     "PreferredMode"   "1024x768"
EndSection

Valid values for the PreferredMode option can be listed in an X session with the following command:

xrandr --query