Asterinas: A new Linux-compatible kernel project

Summary

Welcome to LWN.net The following subscription-only content has been made available to you by an LWN subscriber. Thousands of subscribers depend on LWN for the best news from the Linux and free software communities. If you enjoy this article, please consider subscribing to LWN. Thank you for visiting LWN.net! June 19, 2025 This article was contributed by Ronja Koistinen Born from research at the Southern University of Science and Technology (SUSTech) in Shenzen, China, Asterinas is a new Linux-ABI-compatible kernel project written in Rust, based on what the authors call a "framekernel architecture". The project overlaps somewhat with the goals of the Rust for Linux project, but approaches the problem space from a different direction by trying to get the best from both monolithic and microkernel designs. What's a framekernel? The framekernel concept is explained in the September 2024 paper "Framekernel: A Safe and Efficient Kernel Architecture via Rust-based Intra-kernel Privilege Separation" by Yuke Peng et al. A fuller version of the paper was published in early June. Traditionally, monolithic kernels lump everything into one kernel-mode address space, whereas microkernels only implement a minimal trusted computing base (TCB) in kernel space and rely on user-mode services for much of the operating system's functionality. This separation implies the use of interprocess communication (IPC) between the microkernel and those services. This IPC often has a performance impact, which is a big part of why microkernels have remained relatively unpopular. The core of Asterinas's "framekernel" design is the encapsulation of all code that needs Rust's unsafe features inside a library, enabling the rest of the kernel (the services) to be developed using safe abstractions. Those services remain within the kernel's address space, but only have access to the resources that the core library gives to them. This design is meant to improve the safety of the system while retaining the s...