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>
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 72d6339..c49f79ed 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -802,6 +802,28 @@
}
EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
+void gnttab_foreach_grant(struct page **pages,
+ unsigned int nr_grefs,
+ xen_grant_fn_t fn,
+ void *data)
+{
+ unsigned int goffset = 0;
+ unsigned long xen_pfn = 0;
+ unsigned int i;
+
+ for (i = 0; i < nr_grefs; i++) {
+ if ((i % XEN_PFN_PER_PAGE) == 0) {
+ xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
+ goffset = 0;
+ }
+
+ fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
+
+ goffset += XEN_PAGE_SIZE;
+ xen_pfn++;
+ }
+}
+
int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
struct gnttab_map_grant_ref *kmap_ops,
struct page **pages, unsigned int count)