xen/grant-table: Add an helper to iterate over a specific number of grants

With the 64KB page granularity support on ARM64, a Linux page may be
split accross multiple grant.

Currently we have the helper gnttab_foreach_grant_in_grant to break a
Linux page based on an offset and a len, but it doesn't fit when we only
have a number of grants in hand.

Introduce a new helper which take an array of Linux page and a number of
grant and will figure out the address of each grant.

Signed-off-by: Julien Grall <julien.grall@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index e17a4b381a16..34b1379f9777 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -264,6 +264,12 @@ static inline void gnttab_for_one_grant(struct page *page, unsigned int offset,
         gnttab_foreach_grant_in_range(page, offset, len, fn, data);
 }
 
+/* Get @nr_grefs grants from an array of page and call fn for each grant */
+void gnttab_foreach_grant(struct page **pages,
+                          unsigned int nr_grefs,
+                          xen_grant_fn_t fn,
+                          void *data);
+
 /* Get the number of grant in a specified region
  *
  * start: Offset from the beginning of the first page