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 [1]Linux 6.19 .

Last week [2]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 [3]this pull that was merged to Git yesterday by Linus Torvalds.



[1] https://www.phoronix.com/search/Linux+6.19

[2] https://www.phoronix.com/news/RAMDAX-NVDIMM-Merged-Linux-6.19

[3] https://lore.kernel.org/lkml/20251208064614.GA2485915@liuwe-devbox-debian-v2.local/