v44.0

This release has been tracked in our roadmap project as iteration
v44.0. The following user visible changes have been made:

Configurable virtio-iommu Address Width

The iommu_address_width option has been added to --platform to allow users
to limit the virtio-iommu address space in the guest. (#6900)

Notable Performance Improvements

The VIRTIO_BLK_F_SEG_MAX feature has been enabled for virtio-block devices,
which brings significant performance improvements on throughput. (#6885)

The io_uring entries are no longer forced to use async helper workers,
delegating the decision to the kernel. This change resolved the issue of having
excessive amount of worker threads when io_uring is being used, which is
expected to improve performance, such as reducing memory usage and reduce CPU
contention.

New Fuzzers

Our continuous fuzzing infrastructure is augmented with two new fuzzers to cover
x86 instruction emulator and virtio-vsock.

Notable Bug Fixes

• Fix short read and short write that impact QCOW and VHDX support. (block: fix short read and short write in AsyncAdaptor #6884)
• Various bug fixes on VHDX support. (Fix bugs in VHDX code #6890, Properly account for bytes read and written in VHDX IO code #6899)

Contributors

Many thanks to everyone who has contributed to our release:

• Arvind Vasudev avasudev@crusoeenergy.com
• Bo Chen bo.arvin.chen@gmail.com
• Nikolay Edigaryev edigaryev@gmail.com
• Rob Bradford rbradford@rivosinc.com
• Ruoqing He heruoqing@iscas.ac.cn
• Wei Liu liuwe@microsoft.com

v43.0

This release has been tracked in our roadmap
project as iteration
v43.0. The following user visible changes have been made:

Live Migration over TCP Connections

Support has been added to enable direct live migration from two hosts via TCP
connections. This supplements the existing support for migrating over a UNIX
socket which can then be tunnelled as desired. The documentation has been
updated. (#6850)

Notable Performance Improvements

The VIRTIO_RING_F_INDIRECT_DESC feature has been enabled for virtio-block
devices. This significantly increases the throughput of the devices with a
small negative impact on latency. (#6826)

Notable Bug Fixes

• Cloud Hypervisor now accepts VFIO devices that use I/O PCI BARs on non x86-64
  architectures. Whether they function depends on the host PCI host bridge
  support - previously they would be rejected even if the driver did not use
  these BARs. (vmm: support PCI I/O regions on all architectures #6871)
• Command line groups were adjusted to ensure that at least one payload
  parameter was provided if any other VM parameters provided. (Require payload argument when parsing any other VM argument #6832)

Contributors

Many thanks to everyone who has contributed to our release:

• Alyssa Ross hi@alyssa.is
• Andrew Consroe aconz2@gmail.com
• Bo Chen bo.arvin.chen@gmail.com
• Jinrong Liang cloudliang@tencent.com
• Julian Stecklina julian.stecklina@cyberus-technology.de
• Muminul Islam muislam@microsoft.com
• Rob Bradford rbradford@rivosinc.com
• Ruoqing He heruoqing@iscas.ac.cn
• Wojtek Czekalski wczekalski@me.com