CPSLab Cyber-Physical Systems Lab, Boston University

Publications Real-Time Virtualization

The Omnivisor: A real-time static partitioning hypervisor extension for heterogeneous core virtualization over MPSoCs

Daniele Ottaviano, Francesco Ciraolo, Renato Mancuso, Marcello Cinque

36th Euromicro Conference on Real-Time Systems (ECRTS 2024), July 2024, Lille, France

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Figure 1 A block diagram illustrates the Omnivisor model, showcasing varied temporal and spatial isolation mechanisms across CPU clusters, emphasizing their heterogeneity. The arrows indicate the flow of a request from an initiator to the accessed resource (memory or I/O).

Abstract

Following the needs of industrial applications, virtualization has emerged as one of the most effective approaches for the consolidation of mixed-criticality systems while meeting tight constraints in terms of space, weight, power, and cost (SWaP-C). In embedded platforms with homogeneous processors, a wealth of works have proposed designs and techniques to enforce spatio-temporal isolation by leveraging well-understood virtualization support. Unfortunately, achieving the same goal on heterogeneous MultiProcessor Systems-on-Chip (MPSoCs) has been largely overlooked. Modern hypervisors are designed to operate exclusively on main cores, with little or no consideration given to other co-processors within the system, such as small microcontroller-level CPUs or soft-cores deployed on programmable logic (FPGA). Typically, hypervisors consider co-processors as I/O devices allocated to virtual machines that run on primary cores, yielding full control and responsibility over them. Nevertheless, inadequate management of these resources can lead to spatio-temporal isolation issues within the system. In this paper, we propose the Omnivisor model as a paradigm for the holistic management of heterogeneous platforms. The model generalizes the features of real-time static partitioning hypervisors to enable the execution of virtual machines on processors with different Instruction Set Architectures (ISAs) within the same MPSoC. Moreover, the Omnivisor ensures temporal and spatial isolation between virtual machines by integrating and leveraging a variety of hardware and software protection mechanisms. The presented approach not only expands the scope of virtualization in MPSoCs but also enhances the overall system reliability and real-time performance for mixed-criticality applications. A full open-source reference implementation of the Omnivisor based on the Jailhouse hypervisor is provided, targeting ARM real-time processing units and RISC-V soft-cores on FPGA. Experimental results on real hardware show the benefits of the solution, including enabling the seamless launch of virtual machines on different ISAs and extending spatial/temporal isolation to heterogenous cores with enhanced regulation policies.

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Cite this paper

@inproceedings{Omnivisor_ECRTS24,
  title     = {{The Omnivisor: A real-time static partitioning hypervisor extension for heterogeneous core virtualization over MPSoCs}},
  author    = {Ottaviano, Daniele and Ciraolo, Francesco and Mancuso, Renato and Cinque, Marcello},
  booktitle = {36th Euromicro Conference on Real-Time Systems (ECRTS 2024)},
  year      = 2024,
  month     = jul,
  publisher = {Schloss Dagstuhl–Leibniz-Zentrum fuer Informatik},
  address   = {Lille, France},
  doi       = {10.4230/LIPIcs.ECRTS.2024.6},
  url       = {https://doi.org/10.4230/LIPIcs.ECRTS.2024.6}
}

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