Install Xen hypervison

You'll need to install a bunch of packages required to compile Xen from source:

gcc
make
binutils
zlib-devel
python-devel
openssl-devel
xorg-x11-server-devel
iproute
udev OR hotplug
dev86
mercurial
iasl
gettext-kde (for Ubuntu machines)
bridge-utils 

download http://bits.xensource.com/oss-xen/release/4.2.1/xen-4.2.1.tar.gz 

$ tar xzf xen-4.1.0.tar.gz
$ cd xen-4.1.0
$ make xen && make tools
# make install-xen && make install-tools