Evaluating Guest Isolation on a Hypervised System

Abstract

As mixed-critical systems become more prevalent in automotive systems, virtualization has emerged as a promising solution to reduce system complexity and improve costefficiency. This thesis investigates the ability of hypervisors to maintain temporal isolation between virtual machines (VMs) under conditions that simulate disturbances. Two general-purpose hypervisors, Xen and QEMU/KVM, are evaluated on an ARM-based Pi 4B using ZephyrOS as a Real-Time Operating System (RTOS) in both measurer and stressor roles. A test framework was developed to benchmark low-level latency operations and applicationlevel performance using adapted MiBench workloads (Qsort and Basicmath), and longterm scheduling behavior through thread metrics. Performance metrics were collected under various configurations, including stressed and unstressed scenarios across different CPU core assignments. The results show that while both hypervisors provide a baseline level of temporal isolation, their behaviors diverge under stress. QEMU/KVM generally demonstrates better raw performance and responsiveness, whereas Xen offers more predictable behavior in specific scheduling configurations. These findings underscore the trade-offs involved in selecting a hypervisor for real-time automotive applications and contribute to a broader understanding of how virtualization affects temporal determinism in embedded systems.