Cloud Hypervisor v36.0 Released!

Posted November 2, 2023 by Cloud Hypervisor Team ‐ 2 min read

This release has been tracked in our roadmap project as iteration v36.0. The following user visible changes have been made:

Command Line Changes

We switched back to use the clap crate to create our command line, since the argh crate is barely maintained. There were several syntax changes:

  • All --option value commands now are --option=value.
  • The --disk DISK1 --disk DISK2 command now is --disk DISK1 DISK2.
  • The -v -v -vcommand now is -vvv.

Note: the released binary size increased around 0.3M due to this change.

Enabled Features Reported via API Endpoint and CLI

Now the enabled (Cargo) features of the running Cloud Hypervisor instance can be queried via API endpoint (/ and CLI (--version -v).

NUMA Support for PCI segments

The --numa command is augmented with a new option pci_segment=, so that users can define the relationship between PCI segments and NUMA nodes. Examples can be found from the memory documentation

CPU Topology Support on AMD Platforms

Now the CPU topology on x86_64 platforms supports multiple vendors.

Unix Socket Backend for Serial Port

The --serial command is augmented with a new option socket=, allowing users to access the serial port using a Unix socket.

AIO Backend for Block Devices

An AIO backend is added for virtio-block devices to improve block device performance when the io_uring feature is not supported by the host Operating System.

Documentation Improvements

Notable Bug Fixes

  • Fix a deadlock when TDX is enabled (#5845)
  • Only advertise AMX feature bits to guest when the AMX cpu feature is enabled (#5834)
  • Correct default value for vCPU topology on AArch64 (#5893)


Many thanks to everyone who has contributed to our release:


See the GitHub Release for the release assets.