Here how it worked for me.
The lessons I learned:
I wanted to use xen as hypervisor so I can play around with different OS a software without ruining my primary system.
So first I downloaded the 64 bit client version from Ubuntu and followed Martins guide http://martincarstenbach.wordpress.com/2011/11/30/getting-started-with-xen-virtualisation-on-ubuntu-11-10/. Thanks Martin, great work.
A few things I had to figure out myself.
I had one problem with my Ubuntu 64 Bit client. Even though I installed on an Intel box I had to use the xen-hypervisor-4.1-amd64 package it seems also to cover the intel 64 Bit machines. The i386 package did not work.
Then I wanted to get the virtualisation GUI to work: To get virsh up and running I hat to add “export VIRSH_DEFAULT_CONNECT_URI=xen:///” to root .bashrc file. Then it started without problems.
Now xen is up and running. Just need to create a guest VM. Before I could do that I had to enable the virtualisation options im my EFI BIOS. After a reboot and changing the BIOS settings everything worked fine, but I could not see a virtual network bridge on my system.
I wanted my vm to share the network interface with the physical machine. I had to do the following to Configuring the network:
iface xenbr0 inet dhcp
one reboot later the bridge was up.
now I had to deal with some virt-manager errors.
I had to do an “ln -s qemu-linaro qemu” in /usr/share to get rid of some “Could not read keymap file: ‘/usr/share/qemu/keymaps/en-us” errors and to get rid of the problem.
ln -s ../lib/xen-4.1/ xen
A good idea is to monitor the xen logs in /var/log/xen for errors.
After these steps I could create a VM and install the guest OS.