Re: [PATCH 1/1] x86/hyperv: Add comments about hv_vpset and var size hypercall input args

[Wei Liu]

On Tue, Mar 18, 2025 at 02:49:19PM -0700, mhkelley58@xxxxxxxxx wrote:
> From: Michael Kelley <mhklinux@xxxxxxxxxxx>
> 
> Current code varies in how the size of the variable size input header
> for hypercalls is calculated when the input contains struct hv_vpset.
> Surprisingly, this variation is correct, as different hypercalls make
> different choices for what portion of struct hv_vpset is treated as part
> of the variable size input header. The Hyper-V TLFS is silent on these
> details, but the behavior has been confirmed with Hyper-V developers.
> 
> To avoid future confusion about these differences, add comments to
> struct hv_vpset, and to hypercall call sites with input that contains
> a struct hv_vpset. The comments describe the overall situation and
> the calculation that should be used at each particular call site.
> 
> No functional change as only comments are updated.
> 
> Signed-off-by: Michael Kelley <mhklinux@xxxxxxxxxxx>

Applied to hyperv-next.	Thanks.