Displaying X clients on the host X server
First of all, make sure that you have the X clients installed in the
filesystem that you're going to boot. Then boot the virtual machine
and set up networking to the host. See the
networking tutorial for instructions on
doing that. If necessary, xhost the virtual machine on the host.
At this point, set your display to the host
UML# export DISPLAY=host-ip:0
and run whatever X clients you want.
Running a local virtual X server
Before booting the virtual machine, make sure that it contains Xnest,
which is the UML X server. On some distributions, it is packaged with
the X clients, and on others, it's not. Then boot the virtual
machine, and follow the directions above to run Xnest displaying on
the host. Xnest will create a window which will be its root window.
All clients of the Xnest will be displayed within that window.
Now, set your display to the default local X server:
UML# export DISPLAY=:0
and run whatever X clients you like. I normally run fvwm2, which
gives me enough of an X environment that I don't need to go back to
See the virtual network and X
session screenshots for examples of X in action under UML.