Partitioned Embedded Architecture Based on Hypervisor: The XtratuM Approach

Partitioned software architectures were conceived to fulfill security and avionics requirements where predictability is extremely important. Both, the availability of new processors and an increased necessity of security, have opened new possibilities to use efficiently this approach. Avionic industry has consolidated the Integrated Modular Avionics (IMA) as a solution to manage the software growth in functionality and in efficiency. Now, the aerospace sector is adapting these concepts on its developments. One of the solutions used to achieve partitioned systems is based on virtualisation techniques. In this paper we present XtratuM, a bare-metal hypervisor which implements para-virtualization and dedicated device techniques. XtratuM provides a virtual machine that is 'near' the native one. It permits to execute a set of partitions, containing each one an operating systems and its applications. Security is based on the temporal and spatial isolation properties provided by the hypervisor. This paper describes the main design criteria used to achieve temporal and spatial partition isolation and an approach to extend the trusted environment from the hardware level to the hypervisor level in order to verify the temporal and spatial isolation properties