[PATCH v3 3/5] hyperv: Add new Hyper-V headers in include/hyperv

[Michael Kelley]

From: Nuno Das Neves <nunodasneves at linux.microsoft.com> Sent: Monday, November 25, 2024 3:25 PM
> 
> These headers contain definitions for regular Hyper-V guests (as in
> hyperv-tlfs.h), as well as interfaces for more privileged guests like
> the root partition (aka Dom0).
> 
> These files are derived from headers exported from Hyper-V, rather than
> being derived from the TLFS document. (Although, to preserve
> compatibility with existing Linux code, some definitions are copied
> directly from hyperv-tlfs.h too).
> 
> The new files follow a naming convention according to their original
> use:
> - hdk "host development kit"
> - gdk "guest development kit"
> With postfix "_mini" implying userspace-only headers, and "_ext" for
> extended hypercalls.
> 
> The use of multiple files and their original names is primarily to
> keep the provenance of exactly where they came from in Hyper-V
> code, which is helpful for manual maintenance and extension
> of these definitions. Microsoft maintainers importing new definitions
> should take care to put them in the right file. However, Linux kernel
> code that uses any of the definitions need not be aware of the multiple
> files or assign any meaning to the new names. Linux kernel code should
> always just include hvhdk.h
> 
> Note the new headers contain both arm64 and x86_64 definitions. Some are
> guarded by #ifdefs, and some are instead prefixed with the architecture,
> e.g. hv_x64_*. These conventions are kept from Hyper-V code as another
> tactic to simplify the process of importing and maintaining the
> definitions, rather than splitting them up into their own files in
> arch/x86/ and arch/arm64/.
> 
> These headers are a step toward importing headers directly from Hyper-V
> in the future, similar to Xen public files in include/xen/interface/.
> 
> Signed-off-by: Nuno Das Neves <nunodasneves at linux.microsoft.com>

Reviewed-by: Michael Kelley <mhklinux at outlook.com>