μRTZVisor: A Secure and Safe Real-Time Hypervisor

Abstract

Virtualization has been deployed as a key enabling technology for coping with the ever growing complexity and heterogeneity of modern computing systems. However, on its own, classical virtualization is a poor match for modern endpoint embedded system requirements such as safety, security and real-time, which are our main target. Microkernel-based approaches to virtualization have been shown to bridge the gap between traditional and embedded virtualization. This notwithstanding, existent microkernel-based solutions follow a highly para-virtualized approach, which inherently requires a significant software engineering effort to adapt guest operating systems (OSes) to run as userland components. In this paper, we present µRTZVisor as a new TrustZone-assisted hypervisor that distinguishes itself from state-of-the-art TrustZone solutions by implementing a microkernel-like architecture while following an object-oriented approach. Contrarily to existing microkernel-based solutions, µRTZVisor is able to run nearly unmodified guest OSes, while, contrarily to existing TrustZone-assisted solutions, it provides a high degree of functionality and configurability, placing strong emphasis on the real-time support. Our hypervisor was deployed and evaluated on a Xilinx Zynq-based platform. Experiments demonstrate that the hypervisor presents a small trusted computing base size (approximately 60KB), and a performance overhead of less than 2% for a 10 ms guest-switching rate.

seL4 Microkernel for Virtualization Use-Cases: Potential Directions towards a Standard VMM

“…One of the benefits would be the heterogeneity that it can bring, being possible to deploy various operating systems and applications in the same hardware [29]. Moreover, it improves the system's security by achieving security through separation [30,31]. It is achieved as each operating system has its own space, not having an explicit connection with others, keeping software instances isolated.…”

Embedded Microprocessor Extension Design and Optimization for Real-Time Edge Computing

“…Hybrid Mechanism. The combination of software and hardware refers to adding a new mode to the hardware, providing corresponding software support, and using the combination of software and hardware to solve isolation and resource scheduling, such as TrustZone [34], ViMoExpress [35], ARMithril [36], and RTZVisor [37]. It has become a promising research direction in real-time area.…”

Virtualizing Mixed-Criticality Systems: A Survey on Industrial Trends and Issues

“…The same authors proposed RTZVisor [113] and his successor µRTZVisor [114] as a solution for multi-guest OS scenario. In that case, the hypervisor software still runs in the monitor mode, while each of the guest OSes can run switching between the non-secure and secure worlds.…”

“…The domain-0 can preempt partitions running in different domains. In [114], Martins et al evaluate time switching between guest partitions and secure tasks or between secure tasks; the results show that the switching process takes about 19.4 and 10.4 µs, respectively. µRTZVisor provides in the worst case about 180 µs of interrupt latencies.…”