Currently at Virtualbox has introduced UEFI support in 3.1 release. But there is one issue with X server. When trying configure X with -configure. Resulted xorg.conf.new looks right except missed Modes. Observing code I've supposed that missed information should be somehow fetched from screen info (prepared by EFIFB) via ioctl(..,FBIOGET_FSCREENINFO,...), but for some reasons it isn't called and doing strace of X -configure the /dev/fb0 is open and than immediately closed ([pastebin.org]). So the question is what should be added in VirtualBox/UEFI firmware to get full xorg.conf?