Microsoft Has Many Hyper-V Virtualization Improvements For Linux 6.19

Written by Michael Larabel in Microsoft on 9 December 2025 at 09:30 AM EST. 7 Comments

For benefiting their Azure cloud and other users of Hyper-V virtualization at large, Microsoft has rolled out a number of feature additions and improvements for their Hyper-V kernel code in Linux 6.19.

Last week Microsoft's RAMDAX driver was upstreamed to the Linux kernel while this week the Windows company sent in a number of Hyper-V improvements for this next version of the kernel. The Hyper-V pull landed more work around confidental computing "CoCo" for VMs, secure AVIC support for Linux guests, a new "L1VH" mode for Linux to drive the hypervisor running the Azure Host directly, ARM64 improvements, and more:

- Enhancements to Linux as the root partition for Microsoft
Hypervisor.
* Support a new mode called L1VH, which allows Linux to drive the hypervisor running the Azure Host directly.
* Support for MSHV crash dump collection.
* Allow Linux's memory management subsystem to better manage guest memory regions.
* Fix issues that prevented a clean shutdown of the whole system on bare metal and nested configurations.
* ARM64 support for the MSHV driver.
* Various other bug fixes and cleanups.
- Add support for Confidential VMBus for Linux guest on Hyper-V.
- Secure AVIC support for Linux guests on Hyper-V.
- Add the mshv_vtl driver to allow Linux to run as the secure kernel in a higher virtual trust level for Hyper-V.

More details on these numerous Hyper-V improvements for Linux 6.19 via this pull that was merged to Git yesterday by Linus Torvalds.