xen: mark grant mapped pages as foreign
Use the "foreign" page flag to mark pages that have a grant map. Use
page->private to store information of the grant (the granting domain
and the grant reference).
Signed-off-by: Jennifer Herbert <jennifer.herbert@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index 949803e..d3bef563 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -45,6 +45,8 @@
#include <asm/xen/hypervisor.h>
#include <xen/features.h>
+#include <linux/mm_types.h>
+#include <linux/page-flags.h>
#define GNTTAB_RESERVED_XENSTORE 1
@@ -185,4 +187,22 @@
void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count);
void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count);
+
+struct xen_page_foreign {
+ domid_t domid;
+ grant_ref_t gref;
+};
+
+static inline struct xen_page_foreign *xen_page_foreign(struct page *page)
+{
+ if (!PageForeign(page))
+ return NULL;
+#if BITS_PER_LONG < 64
+ return (struct xen_page_foreign *)page->private;
+#else
+ BUILD_BUG_ON(sizeof(struct xen_page_foreign) > BITS_PER_LONG);
+ return (struct xen_page_foreign *)&page->private;
+#endif
+}
+
#endif /* __ASM_GNTTAB_H__ */