Guest drivers
https://www.virtualbox.org/wiki/LinuxAdditionsDebugThe vboxvideo graphics driver drives the guest video hardware emulation. It does not depend on other drivers, programs the emulated hardware directly and is not expected to be running on systems with X.Org servers older than and including 1.16, as they are not compatible with it and use special drivers, or on systems with Linux kernels older than version 3.11.
