# microsoft/openvmm

Home of OpenVMM and OpenHCL

Repository: https://github.com/microsoft/openvmm
Canonical: https://ross.abutalabs.com/products/openvmm
Homepage: http://openvmm.dev/
Language: Rust
License: MIT
License Family: permissive
Topics: confidential-computing, rust, vmm
Last push: 2026-08-26T19:51:30+00:00

## Health v2 (maintenance only)
Score: 88/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 86, longevity 65
- inputs: {"age_days": 915, "days_push": 7, "days_rel": 19, "gap_med": 31.5, "n_releases_24m": 3}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1877, forks 227 (observed 2026-08-28T04:05:47.846656+00:00)

## What it is
OpenVMM is a modular, cross-platform Virtual Machine Monitor (VMM) written in Rust, developed by Microsoft. It also hosts OpenHCL, a paravisor for running trusted management software inside confidential VMs.

## Use cases
- run and manage virtual machines with a lightweight Rust-based VMM
- build a paravisor for confidential computing VMs
- develop and test virtualization components in Rust
- run OpenHCL inside Hyper-V VMs
- experiment with modular hypervisor architectures

## When to choose
- you need a cross-platform, modular VMM written in Rust
- you are building confidential computing solutions requiring a paravisor
- you want to contribute to or extend an open-source virtualization stack
- you need fine-grained control over VM device emulation

## When to avoid
- you need a mature, production-hardened hypervisor like KVM or Hyper-V for general workloads
- you only need simple desktop virtualization with a GUI
- your team is not comfortable working with low-level systems code in Rust

## Facets
- artifact type: application
- maturity: active
- function: security, developer-tools
- domain: security, operating-systems
- platform: windows, rust, cross-platform
- tags: vmm, hypervisor, paravisor, openhcl, confidential-computing, virtualization, infrastructure, linux

## Member repositories
- microsoft/openvmm (main) score 88

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:47.846656+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:14:42.946577+00:00, confidence not recorded.
  - readme: https://github.com/microsoft/openvmm (fetched 2026-08-28T04:05:47.846656+00:00, sha a380477f87f8)
  - homepage: http://openvmm.dev/ (fetched 2026-08-29T10:53:28.425174+00:00, sha 071dfc08efff)
- Data as of 2026-08-30T08:39:29.467469+00:00.