In a recent development, the code base of the Linux kernel has been updated to version 6.15, with changes including the ability to use Linux as a root environment (DOM0) for the Hyper-V Hypervisor by Microsoft. The host-reduction is responsible for managing the hypervisor, launching guest systems, allocating resources, and ensuring interaction with virtual machines. Control of the hypervisor in Linux is done through the /DEV/MSHV device, with the addition of the ability to disable individual CPU cores (CPU Offlineing) in virtual machines using Hyper-V.
The use of Linux as a hostualization system for Hyper-V was first introduced in 2020. While Linux for Hyper-V management is already in use in Azure Linux distribution and Microsoft infrastructure, third-party projects previously had to use separate patches. Now, these patches are integrated into the main kernel. Hyper-V drivers for guest systems were added to the Linux kernel in 2009, beginning with release 2.6.32.
The decision to utilize Linux for managing the Hyper-V hypervisor aims to simplify support and enhance server performance for Microsoft cloud systems. Since 2018, the number of guest Linux systems in the Azure cloud service has surpassed Windows, driving the need for this integration.
Moreover, Microsoft is working on a hypervisor called Hyperlight, designed as a library for embedding in applications. This hypervisor facilitates the performance of specific functions in lightweight virtual machines (Micro-VM) and manages data exchange with these functions. Hyperlight may be necessary for isolating untrusted code segments or those requiring enhanced protection.
One of the notable changes is the introduction of Hyperlight-Wasm, a framework enabling the execution of WebAssembly (WASM) modules and components in separate virtual machines. This feature is particularly useful for running third-party WebAssembly code securely. Hyperlight-Wasm can operate on Windows (WHP-Windows Hypervisor