Microsoft lauds Hyperlight Wasm for WebAssembly workloads

Microsoft has unveiled Hyperlight Wasm, a virtual machine “micro-guest” that can run WebAssembly component workloads written in a multitude of languages including C and Python.

Introduced March 26, Hyperlight Wasm serves as a Rust library crate. Wasm modules and components can be run in a VM-backed sandbox. The purpose of Hyperlight Wasm is to enable applications to safely run untrusted or third-party Wasm code within a VM with very low latency/overhead. It is built on Hyperlight, introduced last year as an open source Rust library to execute small, embedded functions using hypervisor-based protection. Workloads in the Hyperlight Wasm guest can run for compiled languages such as C, Go, and Rust as well as for interpreted languages including Python, JavaScript, and C#. But a language runtime must be included as part of the image.

Hyperlight Wasm remains experimental and is not considered production-ready by its developers, according to the project’s GitHub page. This page also contains instructions for building with the technology. Hyperlight Wasm takes advantage of WASI (WebAssembly System Interface) and the WebAssembly Component Model. It can allow developers to implement a small set of high-level, performant abstractions in almost any execution environment and provides a fast, hardware-protected but widely compatible execution environment.

Building Hyperlight with a WebAssembly runtime enables any programming language to execute in a protected Hyperlight micro-VM without any prior knowledge of Hyperlight. Program authors are just compiling for the wasm32-wasip2 target, meaning programs can use runtimes such as Wasmtime or Jco, Microsoft said. Programs also can be run on a server for Nginx Unit, Spin, WasmCloud, or, now, Hyperlight Wasm. In an ideal scenario, developers wouldn’t need to think about what runtime their code will run on as they are developing it. Also, by combining Hyperlight with WebAssembly, Microsoft said it was achieving more security and performance than traditional VMs by doing less work overall. Wasmtime provides strong isolation boundaries for Wasm workloads via a software-defined sandbox, Microsoft said.

Plans call for enabling Hyperlight Wasm to work on Arm64 processors. Thus far, planning has centered on using WASI on Hyperlight for portability between operating systems and VMs. But Wasm applications are portable between different instruction sets. Also, Hyperlight Wasm will soon be extended with default bindings for some WASI interfaces.