- [v0.6.0](#v060) - [Directly Assigned Devices Hotplug](#directly-assigned-devices-hotplug) - [Shared Filesystem Improvements](#shared-filesystem-improvements) - [Block and Networking IO Self Offloading](#block-and-networking-io-self-offloading) - [Command Line Interface](#command-line-interface) - [PVH Boot](#pvh-boot) - [Contributors](#contributors) - [v0.5.1](#v051) - [v0.5.0](#v050) - [Virtual Machine Dynamic Resizing](#virtual-machine-dynamic-resizing) - [Multi-Queue, Multi-Threaded Paravirtualization](#multi-queue-multi-threaded-paravirtualization) - [New Interrupt Management Framework](#new-interrupt-management-framework) - [Development Tools](#development-tools) - [Kata Containers Integration](#kata-containers-integration) - [Contributors](#contributors) - [v0.4.0](#v040) - [Dynamic virtual CPUs addition](#dynamic-virtual-cpus-addition) - [Programmatic firmware tables generation](#programmatic-firmware-tables-generation) - [Filesystem and block devices vhost-user backends](#filesystem-and-block-devices-vhost-user-backends) - [Guest pause and resume](#guest-pause-and-resume) - [Userspace IOAPIC by default](#userspace-ioapic-by-default) - [PCI BAR reprogramming](#pci-bar-reprogramming) - [New `cloud-hypervisor` organization](#new-cloud-hypervisor-organization) - [Contributors](#contributors-1) - [v0.3.0](#v030) - [Block device offloading](#block-device-offloading) - [Network device backend](#network-device-backend) - [Virtual sockets](#virtual-sockets) - [HTTP based API](#http-based-api) - [Memory mapped virtio transport](#memory-mapped-virtio-transport) - [Paravirtualized IOMMU](#paravirtualized-iommu) - [Ubuntu 19.10](#ubuntu-1910) - [Large memory guests](#large-memory-guests) - [v0.2.0](#v020) - [Network device offloading](#network-device-offloading) - [Minimal hardware-reduced ACPI](#minimal-hardware-reduced-acpi) - [Debug I/O port](#debug-io-port) - [Improved direct device assignment](#improved-direct-device-assignment) - [Improved shared filesystem](#improved-shared-filesystem) - [Ubuntu bionic based CI](#ubuntu-bionic-based-ci) - [v0.1.0](#v010) - [Shared filesystem](#shared-filesystem) - [Initial direct device assignment support](#initial-direct-device-assignment-support) - [Userspace IOAPIC](#userspace-ioapic) - [Virtual persistent memory](#virtual-persistent-memory) - [Linux kernel bzImage](#linux-kernel-bzimage) - [Console over virtio](#console-over-virtio) - [Unit testing](#unit-testing) - [Integration tests parallelization](#integration-tests-parallelization) # v0.6.0 This release has been tracked through the [0.6.0 project](https://github.com/cloud-hypervisor/cloud-hypervisor/projects/7). Highlights for `cloud-hypervisor` version 0.6.0 include: ### Directly Assigned Devices Hotplug We continued our efforts around supporting dynamically changing the guest resources. After adding support for CPU and memory hotplug, Cloud Hypervisor now supports hot plugging and hot unplugging directly assigned (a.k.a. `VFIO`) devices into an already running guest. This closes the features gap for providing a complete Kata Containers workloads support with Cloud Hypervisor. ### Shared Filesystem Improvements We enhanced our shared filesystem support through many `virtio-fs` improvements. By adding support for DAX, parallel processing of multiple requests, `FS_IO`, `LSEEK` and the `MMIO` virtio transport layer to our `vhost_user_fs` daemon, we improved our filesystem sharing performance, but also made it more stable and compatible with other `virtio-fs` implementations. ### Block and Networking IO Self Offloading When choosing to offload the paravirtualized block and networking I/O to an external process (through the `vhost-user` protocol), Cloud Hypervisor now automatically spawns its default `vhost-user-blk` and `vhost-user-net` backends into their own, separate processes. This provides a seamless parvirtualized I/O user experience for those who want to run their guest I/O into separate executions contexts. ### Command Line Interface More and more Cloud Hypervisor services are exposed through the [Rest API](https://github.com/cloud-hypervisor/cloud-hypervisor/blob/master/vmm/src/api/openapi/cloud-hypervisor.yaml) and thus only accessible via relatively cumbersome HTTP calls. In order to abstract those calls into a more user friendly tool, we created a Cloud Hypervisor Command Line Interface (CLI) called `ch-remote`. The `ch-remote` binary is created with each build and available e.g. at `cloud-hypervisor/target/debug/ch-remote` when doing a debug build. Please check `ch-remote --help` for a complete description of all available commands. ### PVH Boot In addition to the traditional Linux boot protocol, Cloud Hypervisor now supports direct kernel booting through the [PVH ABI](https://xenbits.xen.org/docs/unstable/misc/pvh.html). ### Contributors With the 0.6.0 release, we are welcoming a few new contributors. Many thanks to them and to everyone that contributed to this release: * Alejandro Jimenez * Arron Wang * Bin Liu * Bo Chen * Cathy Zhang * Eryu Guan * Jose Carlos Venegas Munoz * Liu Bo * Qiu Wenbo * Rob Bradford * Samuel Ortiz * Sebastien Boeuf * Sergio Lopez # v0.5.1 This is a bugfix release branched off v0.5.0. It contains the following fixes: * Update DiskConfig to contain missing disk control features (#790) - Samuel Ortiz and Sergio Lopez * Prevent memory overcommit via virtio-fs (#763) - Sebastien Boeuf * Fixed error reporting for resize command - Samuel Ortiz * Double reboot workaround (#783) - Rob Bradford * Various CI and development tooling fixes - Sebastien Boeuf, Samuel Ortiz, Rob Bradford # v0.5.0 This release has been tracked through the [0.5.0 project](https://github.com/cloud-hypervisor/cloud-hypervisor/projects/6). Highlights for `cloud-hypervisor` version 0.5.0 include: ### Virtual Machine Dynamic Resizing With 0.4.0 we added support for CPU hot plug, and 0.5.0 adds CPU hot unplug and memory hot plug as well. This allows to dynamically resize Cloud Hypervisor guests which is needed for e.g. Kubernetes related use cases. The memory hot plug implementation is based on the same framework as the CPU hot plug/unplug one, i.e. hardware-reduced ACPI notifications to the guest. Next on our VM resizing roadmap is the PCI devices hotplug feature. ### Multi-Queue, Multi-Threaded Paravirtualization We enhanced our virtio networking and block support by having both devices use multiple I/O queues handled by multiple threads. This improves our default paravirtualized networking and block devices throughput. ### New Interrupt Management Framework We improved our interrupt management implementation by introducing an Interrupt Manager framework, based on the currently on-going [rust-vmm vm-device](https://github.com/rust-vmm/vm-device) crates discussions. This move made the code significantly cleaner, and allowed us to remove several KVM related dependencies from crates like the PCI and virtio ones. ### Development Tools In order to provide a better developer experience, we worked on improving our build, development and testing tools. Somehow similar to the excellent [Firecracker's devtool](https://github.com/firecracker-microvm/firecracker/blob/master/tools/devtool), we now provide a [dev_cli script](https://github.com/cloud-hypervisor/cloud-hypervisor/blob/master/scripts/dev_cli.sh). With this new tool, our users and contributors will be able to build and test Cloud Hypervisor through a containerized environment. ### Kata Containers Integration We spent some significant time and efforts debugging and fixing our integration with the [Kata Containers](https://github.com/kata-containers) project. Cloud Hypervisor is now a fully supported Kata Containers hypervisor, and is integrated into the project's CI. ### Contributors Many thanks to everyone that contributed to the 0.5.0 release: * Bo Chen * Cathy Zhang * Qiu Wenbo * Rob Bradford * Samuel Ortiz * Sebastien Boeuf * Sergio Lopez * Yang Zhong # v0.4.0 This release has been tracked through the [0.4.0 project](https://github.com/cloud-hypervisor/cloud-hypervisor/projects/4). Highlights for `cloud-hypervisor` version 0.4.0 include: ### Dynamic virtual CPUs addition As a way to vertically scale Cloud-Hypervisor guests, we now support dynamically adding virtual CPUs to the guests, a mechanism also known as CPU hot plug. Through hardware-reduced ACPI notifications, Cloud Hypervisor can now add CPUs to an already running guest and the high level operations for that process are documented [here](https://github.com/cloud-hypervisor/cloud-hypervisor/blob/master/docs/hotplug.md) During the next release cycles we are planning to extend Cloud Hypervisor hot plug framework to other resources, namely PCI devices and memory. ### Programmatic firmware tables generation As part of the CPU hot plug feature enablement, and as a requirement for hot plugging other resources like devices or RAM, we added support for programmatically generating the needed ACPI tables. Through a dedicated `acpi-tables` crate, we now have a flexible and clean way of generating those tables based on the VMM device model and topology. ### Filesystem and block devices vhost-user backends Our objective of running all Cloud Hypervisor paravirtualized I/O to a vhost-user based framework is getting closer as we've added Rust based implementations for vhost-user-blk and virtiofs backends. Together with the vhost-user-net backend that came with the 0.3.0 release, this will form the default Cloud Hypervisor I/O architecture. ### Guest pause and resume As an initial requiremnt for enabling live migration, we added support for pausing and resuming any VMM components. As an intermediate step towards live migration, the upcoming guest snapshotting feature will be based on the pause and resume capabilities. ### Userspace IOAPIC by default As a way to simplify our device manager implementation, but also in order to stay away from privileged rings as often as possible, any device that relies on pin based interrupts will be using the userspace IOAPIC implementation by default. ### PCI BAR reprogramming In order to allow for a more flexible device model, and also support guests that would want to move PCI devices, we added support for PCI devices BAR reprogramming. ### New `cloud-hypervisor` organization As we wanted to be more flexible on how we manage the Cloud Hypervisor project, we decided to move it under a [dedicated GitHub organization](https://github.com/cloud-hypervisor). Together with the [cloud-hypervisor](https://github.com/cloud-hypervisor/cloud-hypervisor) project, this new organization also now hosts our [kernel](https://github.com/cloud-hypervisor/linux) and [firmware](https://github.com/cloud-hypervisor/rust-hypervisor-firmware) repositories. We may also use it to host any rust-vmm that we'd need to temporarily fork. Thanks to GitHub's seamless repository redirections, the move is completely transparent to all Cloud Hypervisor contributors, users and followers. ### Contributors Many thanks to everyone that contributed to the 0.4.0 release: * Cathy Zhang * Emin Ghuliev * Jose Carlos Venegas Munoz * Qiu Wenbo * Rob Bradford * Samuel Ortiz * Sebastien Boeuf * Sergio Lopez * Wu Zongyong # v0.3.0 This release has been tracked through the [0.3.0 project](https://github.com/cloud-hypervisor/cloud-hypervisor/projects/3). Highlights for `cloud-hypervisor` version 0.3.0 include: ### Block device offloading We continue to work on offloading paravirtualized I/O to external processes, and we added support for [vhost-user-blk](https://access.redhat.com/solutions/3394851) backends. This enables `cloud-hypervisor` users to plug a `vhost-user` based block device like [SPDK](https://spdk.io)) into the VMM as their paravirtualized storage backend. ### Network device backend The previous release provided support for [vhost-user-net](https://access.redhat.com/solutions/3394851) backends. Now we also provide a TAP based vhost-user-net backend, implemented in Rust. Together with the vhost-user-net device implementation, this will eventually become the Cloud Hypervisor default paravirtualized networking architecture. ### Virtual sockets In order to more efficiently and securely communicate between host and guest, we added an hybrid implementation of the [VSOCK](http://man7.org/linux/man-pages/man7/vsock.7.html) socket address family over virtio. Credits go to the [Firecracker](https://github.com/firecracker-microvm/firecracker/blob/master/docs/vsock.md) project as our implementation is a copy of theirs. ### HTTP based API In anticipation of the need to support asynchronous operations to Cloud Hypervisor guests (e.g. resources hotplug and guest migration), we added a HTTP based API to the VMM. The API will be more extensively documented during the next release cycle. ### Memory mapped virtio transport In order to support potential PCI-free use cases, we added support for the [virtio MMIO](https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/virtio-v1.1-cs01.html#x1-1440002) transport layer. This will allow us to support simple, minimal guest configurations that do not require a PCI bus emulation. ### Paravirtualized IOMMU As we want to improve our nested guests support, we added support for exposing a [paravirtualized IOMMU](https://github.com/cloud-hypervisor/cloud-hypervisor/blob/master/docs/iommu.md) device through virtio. This allows for a safer nested virtio and directly assigned devices support. To add the IOMMU support, we had to make some CLI changes for Cloud Hypervisor users to be able to specify if devices had to be handled through this virtual IOMMU or not. In particular, the `--disk` option now expects disk paths to be prefixed with a `path=` string, and supports an optional `iommu=[on|off]` setting. ### Ubuntu 19.10 With the latest [hypervisor firmware](https://github.com/cloud-hypervisor/rust-hypervisor-firmware), we can now support the latest [Ubuntu 19.10 (Eoan Ermine)](http://releases.ubuntu.com/19.10/) cloud images. ### Large memory guests After simplifying and changing our guest address space handling, we can now support guests with large amount of memory (more than 64GB). # v0.2.0 This release has been tracked through the [0.2.0 project](https://github.com/cloud-hypervisor/cloud-hypervisor/projects/2). 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](https://access.redhat.com/solutions/3394851) backends. This enables `cloud-hypervisor` users to plug a `vhost-user` based networking device (e.g. [DPDK](https://dpdk.org)) 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](https://www.intel.com/content/www/us/en/support/articles/000005500/boards-and-kits.html) PC debug port. This allows, among other things, for granular guest boot time measurements. See our [debug port documentation](https://github.com/cloud-hypervisor/cloud-hypervisor/blob/master/docs/debug-port.md) 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](https://www.kernel.org/doc/Documentation/filesystems/dax.txt) support to our [virtio-fs](https://virtio-fs.gitlab.io/) 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](https://github.com/cloud-hypervisor/rust-hypervisor-firmware) improvements, we are now able to boot Ubuntu bionic images. We added those to our CI pipeline. # v0.1.0 This release has been tracked through the [0.1.0 project](https://github.com/cloud-hypervisor/cloud-hypervisor/projects/1). Highlights for `cloud-hypervisor` version 0.1.0 include: ### Shared filesystem We added support for the [virtio-fs](https://virtio-fs.gitlab.io/) 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](https://github.com/cloud-hypervisor/cloud-hypervisor/blob/master/docs/fs.md) documentation for more details on how to use virtio-fs with `cloud-hypervisor`. ### Initial direct device assignment support 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](https://github.com/cloud-hypervisor/cloud-hypervisor/blob/master/docs/vfio.md) documentation for more detail on how to directly assign host devices to `cloud-hypervisor` guests. ### Userspace IOAPIC `cloud-hypervisor` supports a so-called split IRQ chip implementation by implementing support for the [IOAPIC](https://wiki.osdev.org/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. ### Virtual persistent memory 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. ### Linux kernel bzImage 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. ### Console over virtio `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. ### Unit testing We now run all unit tests from all our crates directly from our CI. ### Integration tests parallelization The CI cycle run time has been significantly reduced by refactoring our integration tests; allowing them to all be run in parallel.