PORTING OPERATING SYSTEMS TO RUN IN XEN VIRTUAL MACHINES

Semiconductor manufacturers are creating new System on Chips that allow embedded system developers to design consolidated architectures to reduce size, weight, power, and cost. However, combining software functions onto a single computing resource creates safety and security concerns due to reduced fault containment and increased coupling between software components. Safety and security-conscious industries use various software separation solutions to isolate software functions logically in order to achieve a comparable level of decoupling and fault containment that distributed/federated systems enjoy as a by-product of their system architecture. This paper will assess the suitability of common separation solutions for use in embedded systems and explain our preference for Xen, an open source Type I hypervisor. This paper will also examine reasons for porting operating systems to run in virtual machines, also known as paravirtualization, and evaluate how certain properties of operating systems can impact this task. Finally, we will conclude with lessons learned from our efforts paravirtualizing a number of operating systems.