Cloud Hypervisor v0.2.0 Released!

Posted September 10, 2019 by Cloud Hypervisor Team ‐ 2 min read

This release has been tracked through the 0.2.0 project.

Highlights for cloud-hypervisor version 0.2.0 include:

Network device offloading

As part of our general effort to offload paravirtualized I/O to external processes, we added support for vhost-user-net backends. This enables cloud-hypervisor users to plug a vhost-user based networking device (e.g. DPDK) into the VMM as their virtio network backend.

Minimal hardware-reduced ACPI

In order to properly implement and guest reset and shutdown, we implemented a minimal version of the hardware-reduced ACPI specification. Together with a tiny I/O port based ACPI device, this allows cloud-hypervisor guests to cleanly reboot and shutdown.

The ACPI implementation is a cloud-hypervisor build time option that is enabled by default.

Debug I/O port

Based on the Firecracker idea of using a dedicated I/O port to measure guest boot times, we added support for logging guest events through the 0x80 PC debug port. This allows, among other things, for granular guest boot time measurements. See our debug port documentation for more details.

Improved direct device assignment

We fixed a major performance issue with our initial VFIO implementation: When enabling VT-d through the KVM and VFIO APIs, our guest memory writes and reads were (in many cases) not cached. After correctly tagging the guest memory from cloud-hypervisor we’re now able to reach the expected performance from directly assigned devices.

Improved shared filesystem

We added shared memory region with DAX support to our virtio-fs shared file system. This provides better shared filesystem IO performance with a smaller guest memory footprint.

Ubuntu bionic based CI

Thanks to our simple KVM firmware improvements, we are now able to boot Ubuntu bionic images. We added those to our CI pipeline.


See the GitHub Release for the release assets.