I try for now several days to install xen on a Dell Optiplex 755 with 6Gb ram
and two ssd.

I install Leap - I tried everything between minimal install to kde - then I go
to Yast virtualization and add xen and xen tools.

YaST creates the xen menu entries.

Leap - without xen starts without problem, but the xen menu entry stops very
soon in the boot proces, leaving an active (the monitor do not complain), but
black screen.

There is no journal written, journalctrl do not show anything for this boot.

On one of my tests, I videotaped the boot. The last image was:

http://dodin.org/owncloud/index.php/s/BH9qjCX7Xya8fXq

on an other test, I could see very shortly something  like systemctl target
init.

Here an other videotape

http://dodin.info/piwigo/picture.php?/112289-00000/category/5970

this computer is for now reserved to this test, so I can do almost any thing
useful to debug this