Virtualization today, virtualization tomorrow: problems, challenges, and opportunities for mixed-criticality systems

There is an ongoing trend in several embedded industries to consolidate multiple subsystems onto the same hardware platform. For example, in the automotive industry, network-connected infotainment starts to be deployed alongside safety-critical control systems (e.g., steering, brake, ABS). To guarantee the temporal and spatial isolation of these components with different criticalities/safety integrity levels (ASIL), it is nowadays common to rely on virtualization technology. However, there is an erroneous belief that hypervisors are the new magic bullet, working as transparent layers of software that provide perfect guarantees and have no impact on the overall system. In this paper, we provide a comprehensive picture of the state of affairs concerning the use of virtualization in the context of the so called mixed-criticality systems. While sharing our experience on the development of an open-source static partitioning hypervisor (Bao) and implementing the hardware virtualization support of a novel computer architecture (RISC-V), we will (i) cover the main problems and limitations currently affecting existing hypervisor solutions and (ii) discuss the (research) challenges and opportunities lying ahead of us.This work is supported by (i) FCT – Fundação para a Ciência e Tecnologia within the R&D Units Project Scope UIDB/00319/2020 and (ii) European Union’s Horizon Europe research and innovation program under grant agreement No 101070537, project CROSSCON (Cross-platform Open Security Stack for Connected Devices