Microsoft Updates Its WSL2 Linux Kernel With DXGKRNL Improvement, More Features Enabled

Following the Windows Subsystem for Linux 3.0.2 release with support for running WSL2 now on very large servers and also experimental sparse VHD storage support, Microsoft has now released a new version of the WSL2 Linux kernel as their downstream kernel configuration tailored for WSL2 usage. Microsoft's WSL2 Linux kernel continues to be a modified copy of the current Linux 6.18 LTS kernel. The new linux-msft-wsl-6.18.54.1 kernel release has updated against the upstream Linux 6.18.54 release for incorporating all of the latest bug/security fixes. Plus it's pulled in and updated a number of the patches it carries for working optimally in the WSL2 confines. One of the new features of this kernel release is native fence sharing for DXGKRNL, Microsoft's out-of-tree kernel driver used for the DirectX graphics support. The DXGKRNL native fence sharing support is described in this patch as: "Native fence create/open now use the global vmbus channel with the channel lock held, and return the host global sync object via an explicit out-parameter instead of overloading device_handle, so the guest device handle is preserved for later open. Copy results to user-mode before publishing the handle so a failed copy_to_user cannot leave a handle user-mode can still see. Drop the extra kref_get after hmgrtable_assign_handle to match dxgkio_create_sync_object refcounting." The linux-msft-wsl-6.18.54.1 kernel also re-enables Direct Rendering Manager (DRM) and VGEM kernel support, PPP support is restored, ISO9660 support is now built-in rather than as a kernel module, and BPF LSM support is enabled by default. More details on the updated WSL2 Linux kernel flavor via GitHub.