The author explores building a semi-hypervisor for Cortex-M3 microcontrollers (Blue Pill) to provide runtime isolation without TrustZone or an MMU. They leverage the MPU's region-based memory protection and the SVC instruction to create a supervisor model that hands out revocable hardware access to unprivileged applications.
Background
Cortex-M3 is a widely used microcontroller architecture found in affordable boards like STM32 Blue Pill, lacking the security features of higher-end cores. Memory Protection Units (MPU) and supervisor calls are standard Cortex-M features that enable basic isolation without a full MMU.
- Source
- Lobsters
- Published
- Aug 9, 2026 at 02:06 AM
- Score
- 5.0 / 10