Found this somewhere.
Works for me.
Section "ServerLayout" Identifier "BodhiZazen's KVM xorg.conf" Screen 0 "Screen0" 0 0 InputDevice "Mouse0" "CorePointer" InputDevice "Keyboard0" "CoreKeyboard" EndSection Section "Module" Load "record" Load "dri" Load "extmod" Load "glx" Load "dbe" Load "dri2" EndSection Section "InputDevice" Identifier "Keyboard0" Driver "kbd" EndSection Section "InputDevice" Identifier "Mouse0" Driver "vmmouse" Option "Protocol" "SysMouse" Option "Device" "/dev/sysmouse" Option "ZAxisMapping" "4 5 6 7" EndSection Section "Monitor" Identifier "Monitor0" VendorName "Monitor Vendor" ModelName "Monitor Model" HorizSync 20.0 - 50.0 VertRefresh 40.0 - 80.0 Option "DPMS" EndSection Section "Device" Identifier "Card0" Driver "vesa" VendorName "KVM - std" BoardName "GD 5446" BusID "PCI:0:2:0" EndSection Section "Screen" Identifier "Screen0" Device "Card0" Monitor "Monitor0" SubSection "Display" Viewport 0 0 Modes "800x600" EndSubSection EndSection