Make xen_xlate_map_ballooned_pages work with 64K pages. In that case
Kernel pages are 64K in size but Xen pages remain 4K in size. Xen pfns
refer to 4K pages.

Signed-off-by: Shannon Zhao <redacted>
Reviewed-by: Stefano Stabellini <redacted>
---
  drivers/xen/xlate_mmu.c | 26 ++++++++++++++++----------
  1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
index 9692656..28f728b 100644
--- a/drivers/xen/xlate_mmu.c
+++ b/drivers/xen/xlate_mmu.c

@@ -207,9 +207,12 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
  	void *vaddr;
  	int rc;
  	unsigned int i;
+	unsigned long nr_pages;
+	xen_pfn_t xen_pfn = 0;

  	BUG_ON(nr_grant_frames == 0);
-	pages = kcalloc(nr_grant_frames, sizeof(pages[0]), GFP_KERNEL);
+	nr_pages = DIV_ROUND_UP(nr_grant_frames, XEN_PFN_PER_PAGE);
+	pages = kcalloc(nr_pages, sizeof(pages[0]), GFP_KERNEL);
  	if (!pages)
  		return -ENOMEM;

@@ -218,22 +221,25 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
  		kfree(pages);
  		return -ENOMEM;
  	}
-	rc = alloc_xenballooned_pages(nr_grant_frames, pages);
+	rc = alloc_xenballooned_pages(nr_pages, pages);
  	if (rc) {
-		pr_warn("%s Couldn't balloon alloc %ld pfns rc:%d\n", __func__,
-			nr_grant_frames, rc);
+		pr_warn("%s Couldn't balloon alloc %ld pages rc:%d\n", __func__,
+			nr_pages, rc);
  		kfree(pages);
  		kfree(pfns);
  		return rc;
  	}
-	for (i = 0; i < nr_grant_frames; i++)
-		pfns[i] = page_to_pfn(pages[i]);
+	for (i = 0; i < nr_grant_frames; i++) {
+		if ((i % XEN_PFN_PER_PAGE) == 0)
+			xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
+		pfns[i] = pfn_to_gfn(xen_pfn++);
+	}