Re: ARM Yawn -- it's all about the spooks
> The NSA contributions to Xen would be more interesting... what are those?
The NSA has mainly been contributing to the Xen Security Modules (or FLASK) - the Xen equivalent of Linux Security Modules (aka SE Linux) for which they are maintainers. FLASK is compile time disabled, if this is a concern to you. If you are worried, you can cross reference from the MAINTAINERS file and figure out the exact contributions based on that information.
They also are very active in reviewing code from security minded organisations such as Zentific, BitDefender and others: for example vTPM support, etc. They have also done quite a bit of documentation work recently to make security functionality in Xen more accessible to others. Overall, the NSA contributions have been positive and there is no evidence of any backdoors, in the same way that there is no evidence of SE Linux related backdoors.