Dolia: an MPU-backed Framework for Secure Multitenancy on Embedded MCUs

Modern microcontroller units (MCUs) are increasingly powerful, yet often dedicated to a single lightweight application that underutilises their capabilities. Sharing a device among multiple independent stakeholders improves utilisation, but requires strong isolation between tenants to prevent interference and unauthorized access. Additionally, the system must support post-deployment reconfigurability and preserve soft real-time guarantees. Existing solutions rely on virtualization through language-level sandboxing, which provides isolation and heterogeneity but introduces runtime overhead that is incompatible with the real-time constraints of resource-constrained devices.

This paper presents a framework built on top of Zephyr RTOS that enables secure multitenancy on MCUs. The framework leverages PMP-based hardware memory protection for tenant isolation, dynamically loadable applications via Zephyr’s LLEXT subsystem with mTLS-authenticated connection for post-deployment reconfigurability, and a condition-based publisher-subscriber model that minimises kernel-to-user crossings to preserve real-time behaviour. Evaluated on an ESP32-C6 RISC-V SoC, results show a 2.5x overhead for kernel-to-user transitions compared to kernel-to-kernel switches, and approximately 4x faster execution than WebAssembly AOT. A connected vehicle use case demonstrates that soft real-time deadlines are preserved even under adversarial CPU load.

Recommended citation: Julien Gourgue, Cristel Pelsser, and Ramin Sadre. "Dolia: an MPU-backed Framework for Secure Multitenancy on Embedded MCUs." OSPERT'26 Workshop, part of ECRTS 2026.