Run Cloud Virtual Machines Securely and Efficiently

Cloud Hypervisor is an open source Virtual Machine Monitor (VMM) implemented in Rust that focuses on running modern, cloud workloads, with minimal hardware emulation.

Get Started

Get the source on GitHub

Secure 🔒

Minimal emulated devices and implemented in Rust to avoid many common security issues

Fast ⚡️

Boot to userspace in less than 100ms with direct kernel boot

🪟 & 🐧

Supports running modern Linux and Windows guests

Kata Containers

Supported by Kata Containers for running secure containerised workloads

Powerful REST API

Programmatically control the lifecyle of the VM using an HTTP API

Slim

Minimal memory overhead for dense deployments

Cross platform

Runs on both x86-64 and aarch64

Broad device support

Support for wide range of paravirtualised devices and physical device passthrough

Live migration

Migrate VMs from one host to another without interruption

Get Involved:

Cloud Hypervisor is governed openly as part of the Linux Foundation and supported by multiple organisations:

  • Alibaba
  • AMD
  • Ampere
  • ARM
  • ByteDance
  • Cyberus Technology
  • Intel
  • Microsoft
  • Tencent Cloud

Join our Slack community: Invite

Participate in our community activities: Slack channel

Check out and participate in our roadmap on GitHub

For full details of our governance model please see our community repository on GitHub and our founding charter.

For bug reports please use GitHub isssues; for broader community discussions please use our mailing list

Latest news from Cloud Hypervisor project:

Cloud Hypervisor v48.0 Released!

Posted September 12, 2025 by Cloud Hypervisor Team ‐ 2 min read

This release has been tracked in v48.0 group of our roadmap project.

Experimental fw_cfg Device Support

This feature enables passing configuration data and files, such as VM boot configurations (kernel, kernel cmdline, e820 memory map, and ACPI tables), from the host to the guest. (#7117)

Experimental ivshmem Device Support

Support for inter-VM shared memory has been added. For more information, please refer to the ivshmem documentation. (#6703)

Firmware Boot Support on riscv64

In addition to direct kernel boot, firmware boot support has been added on riscv64 hosts. (#7249)

Increased vCPU Limit on x86_64/kvm

The maximum number of supported vCPUs on x86_64 hosts using KVM has been raised from 254 to 8192. (#7299)

Improved Block Performance with Small Block Sizes

Performance for virtio-blk with small block sizes (16KB and below) is enhanced via submitting async IO requests in batches. (#7146)

Faster VM Pause Operation

The VM pause operation now is significantly faster particularly for VMs with a large number of vCPUs. (#7290)

Updated Documentation on Windows Guest Support

Our Windows documentation now includes instructions to run Windows 11 guests, in addition to Windows Server guests. (#7218)

Policy on AI Generated Code

We will decline any contributions known to contain contents generated or derived from using Large Language Models (LLMs). Details can be found in our contributing documentation. (#7162)

Removed SGX Support

The SGX support has been removed, as announced in the deprecation notice two release cycles ago. (#7093)

Notable Bug Fixes

  • Seccomp filter fixes with glibc v2.42 (#7327)
  • Various fixes related to (#7331, #7334, #7335)

Contributors

Many thanks to everyone who has contributed to our release:

Download

See the GitHub Release for the release assets.