v50.0 This release has been tracked in [v50.0 group](https://github.com/orgs/cloud-hypervisor/projects/6/views/6?filterQuery=release%3A%22Release+50%22) of our [roadmap project](https://github.com/orgs/cloud-hypervisor/projects/6/). Configurable Nested Virtualization Option on x86_64 --------------------------------------------------- The `nested=on|off` option has been added to `--cpu` to allow users to configure nested virtualization support in the guest on x86_64 hosts (for both KVM and MSHV). The default value is `on` to maintain consistency with existing behavior. (#7408) Compression Support for QCOW2 ----------------------------- QCOW2 support has been extended to handle compression clusters based on zlib and zstd. (#7462) Notable Performance Improvements -------------------------------- Performance of live migration has been improved via an optimized implementation of dirty bitmap maintenance. (#7468) Live Disk Resizing Support for Raw Images ----------------------------------------- The `/vm.resize-disk` API has been introduced to allow users to resize block devices backed by raw images while a guest is running. (#7476) Developer Experience Improvements --------------------------------- Significant improvements have been made to developer experience and productivity. These include a simplified root manifest, codified and tightened Clippy lints, and streamlined workflows for `cargo clippy` and `cargo test`. (#7489) Improved File-level Locking Support ----------------------------------- Block devices now use byte-range advisory locks instead of whole-file locks. While both approaches prevent multiple Cloud Hypervisor instances from simultaneously accessing the same disk image with write permissions, byte-range locks provide better compatibility with network storage backends. (#7494) Logging Improvements -------------------- Logs now include event information generated by the event-monitor module. (#7512) Notable Bug Fixes ----------------- * Fix several issues around CPUID in the guest (#7485, #7495, #7508) * Fix snapshot/restore for Windows Guest (#7492) * Respect queue size in block performance tests (#7515) * Fix several Serial Manager issues (#7502) * Fix several seccomp violation issues (#7477, #7497, #7518) * Fix various issues around block and qcow (#7526, #7528, #7537, #7546, #7549) * Retrieve MSRs list correctly on MSHV (#7543) * Fix live migration (and snapshot/restore) with AMX state (#7534) Contributors ------------ Many thanks to everyone who has contributed to our release: * Anatol Belski <anbelski@linux.microsoft.com> * Anirudh Rayabharam <anrayabh@microsoft.com> * Bo Chen <bchen@crusoe.ai> * Changyuan Lyu <changyuanl@google.com> * Chengyu Fu <chengyu.fu@linux.alibaba.com> * Connor Brewster <cbrewster@hey.com> * Demi Marie Obenour <demiobenour@gmail.com> * Eugene Korenevsky <ekorenevsky@aliyun.com> * Julian Stecklina <julian.stecklina@cyberus-technology.de> * Matt Moriarity <matt@mattmoriarity.com> * Muminul Islam <muislam@microsoft.com> * Oliver Anderson <oliver.anderson@cyberus-technology.de> * Pascal Scholz <pascal.scholz@cyberus-technology.de> * Philipp Schuster <philipp.schuster@cyberus-technology.de> * Praveen K Paladugu <prapal@linux.microsoft.com> * Rob Bradford <rbradford@rivosinc.com> * Sebastien Boeuf <seb@rivosinc.com> * Songqian Li <sionli@tencent.com> * Stefan Nürnberger <stefan.nuernberger@cyberus-technology.de> * Thomas Prescher <thomas.prescher@cyberus-technology.de> * Wei Liu <liuwe@microsoft.com>