The Haskell Lightweight Virtual Machine (HaLVM) is a port of the Glasgow Haskell Compiler toolsuite that enables developers to write high-level, lightweight virtual machines that can run directly on the Xen hypervisor.

While Galois initially designed the HaLVM to allow for quick and easy prototyping of operating systems components, it has grown over time to allow for a much wider variety of use cases. When connected with the appropriate libraries, the HaLVM can, for example, operate as a network appliance.

The HaLVM: A Simple Platform for Simple Platforms from Xen Project