There’s a nice blog in the Rekall forensics blog about memory forensics of XEN systems:
If you’ve ever taken a memory image of a Linux virtual machine that’s running under XEN in paravirtualization mode and you’ve tried to analyze it you’ll have noticed most of your plugins don’t work (if any). The reason is that XEN’s page tables are funky. XEN uses a technique known as direct mapping which significantly differs from how memory management is done in many other virtualization solutions.
More Information:
http://rekall-forensic.blogspot.com/2015/08/xen-paravirtualization-support-in-rekall.html
http://www.rekall-forensic.com/
https://github.com/google/rekall
Firmware Security 