x86/hyperv: Fix output argument to hypercall that changes page visibility

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 <[email protected]>
Reviewed-by: Nuno Das Neves <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>
Message-ID: <[email protected]>

Author: mhklinux

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))