http://www.brendangregg.com/blog/2014-05-09/xen-feature-detection.html
http://www.dmo.ca/blog/detecting-virtualization-on-linux/
http://unix.stackexchange.com/questions/89714/easy-way-to-determine-virtualization-technology
http://stackoverflow.com/questions/4338768/how-do-i-detect-xen-in-a-python-script
