1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 20c65771017d..d5bb1a33d0a3 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -93,6 +93,7 @@ struct grant_map {
         struct gnttab_map_grant_ref   *kmap_ops;
         struct gnttab_unmap_grant_ref *kunmap_ops;
         struct page **pages;
+        unsigned long pages_vm_start;
 };
 
 static int unmap_grant_pages(struct grant_map *map, int offset, int pages);
@@ -446,9 +447,18 @@ static void gntdev_vma_close(struct vm_area_struct *vma)
         gntdev_put_map(priv, map);
 }
 
+static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma,
+                                                 unsigned long addr)
+{
+        struct grant_map *map = vma->vm_private_data;
+
+        return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT];
+}
+
 static struct vm_operations_struct gntdev_vmops = {
         .open = gntdev_vma_open,
         .close = gntdev_vma_close,
+        .find_special_page = gntdev_vma_find_special_page,
 };
 
 /* ------------------------------------------------------------------ */
@@ -874,6 +884,7 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
                                             set_grant_ptes_as_special, NULL);
                 }
 #endif
+                map->pages_vm_start = vma->vm_start;
         }
 
         return 0;