Re: [PATCH 1/7] x86/hyperv: Fix output argument to hypercall that changes page visibility

Wei Liu
2025-03-10T00:22:10Z

On Wed, Feb 26, 2025 at 02:59:53PM -0800, Nuno Das Neves wrote:
> On 2/26/2025 12:06 PM, mhkelley58@gmail.com wrote:
> > From: Michael Kelley <mhklinux@outlook.com>
> >
> > The hypercall in hv_mark_gpa_visibility() is invoked with an input
> > argument and an output argument. The output argument ostensibly returns
> > the number of pages that were processed. But in fact, the hypercall does
> > not provide any output, so the output argument is spurious.
> >
> > The spurious argument is harmless because Hyper-V ignores it, but in the
> > interest of correctness and to avoid the potential for future problems,
> > remove it.
> >
> > Signed-off-by: Michael Kelley <mhklinux@outlook.com>
> > ---
> > I have not provided a "Fixes:" tag because the error causes no impact.
> > There's no value in backporting the fix.
> >
> > arch/x86/hyperv/ivm.c | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
> > index dd68d9ad9b22..ec7880271cf9 100644
> > --- a/arch/x86/hyperv/ivm.c
> > +++ b/arch/x86/hyperv/ivm.c
> > @@ -464,7 +464,6 @@ static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
> > enum hv_mem_host_visibility visibility)
> > {
> > struct hv_gpa_range_for_visibility *input;
> > - u16 pages_processed;
> > u64 hv_status;
> > unsigned long flags;
> >
> > @@ -493,7 +492,7 @@ static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
> > memcpy((void *)input->gpa_page_list, pfn, count * sizeof(*pfn));
> > hv_status = hv_do_rep_hypercall(
> > HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY, count,
> > - 0, input, &pages_processed);
> > + 0, input, NULL);
> > local_irq_restore(flags);
> >
> > if (hv_result_success(hv_status))
>
> Reviewed-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>

Applied to hyperv-fixes, thanks!