No Principal Too Small: Memory Access Control for Fine-Grained Protection Domains

Modern programs comprise multiple threads of execution inside a single principal -- the process -- with a single protection domain, usually a page table. We propose a hardware enforced, fine-grained memory protection mechanism to divide the process into smaller principals and multiple protection domains. Our approach supports modern software engineering better than traditional processes by enabling developers to align software components with protection mechanisms. We implemented our architecture using a cycle-accurate simulator of a complex out-of-order pipeline and evaluate our solution using open-source benchmarks and synthetic micro benchmarks designed specifically to stress our system.