This release has been tracked through the 0.2.0 project.
Highlights for cloud-hypervisor version 0.2.0 include:
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.
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.
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.
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.
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.
Thanks to our simple KVM firmware improvements, we are now able to boot Ubuntu bionic images. We added those to our CI pipeline.
This release has been tracked through the 0.1.0 project.
Highlights for cloud-hypervisor version 0.1.0 include:
We added support for the virtio-fs shared file
system, allowing for an efficient and reliable way of sharing a filesystem
between the host and the cloud-hypervisor guest.
See our filesystem sharing
documentation for more details on how to use virtio-fs with cloud-hypervisor.
VFIO (Virtual Function I/O) is a kernel framework that exposes direct device
access to userspace. cloud-hypervisor uses VFIO to directly assign host
physical devices into its guest.
See our VFIO
documentation for more detail on how to directly assign host devices to
cloud-hypervisor guests.
cloud-hypervisor supports a so-called split IRQ chip implementation by
implementing support for the IOAPIC.
By moving part of the IRQ chip implementation from kernel space to user space,
the IRQ chip emulation does not always run in a fully privileged mode.
The virtio-pmem implementation emulates a virtual persistent memory device
that cloud-hypervisor can e.g. boot from. Booting from a virtio-pmem device
allows to bypass the guest page cache and improve the guest memory footprint.
The cloud-hypervisor linux kernel loader now supports direct kernel boot from
bzImage kernel images, which is usually the format that Linux distributions
use to ship their kernels. For example, this allows for booting from the host
distribution kernel image.
cloud-hypervisor now exposes a virtio-console device to the guest. Although
using this device as a guest console can potentially cut some early boot
messages, it can reduce the guest boot time and provides a complete console
implementation.
The virtio-console device is enabled by default for the guest console.
Switching back to the legacy serial port is done by selecting
--serial tty --console off from the command line.
We now run all unit tests from all our crates directly from our CI.
The CI cycle run time has been significantly reduced by refactoring our integration tests; allowing them to all be run in parallel.