xen/granttable: Support transitive grants

These allow a domain A which has been granted access on a page of domain B's
memory to issue domain C with a copy-grant on the same page.  This is useful
e.g. for forwarding packets between domains.

Signed-off-by: Annie Li <annie.li@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index 2b492b9..f1e17b7 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -65,6 +65,9 @@ int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
 int gnttab_grant_foreign_access_subpage(domid_t domid, unsigned long frame,
 					int flags, unsigned page_off,
 					unsigned length);
+int gnttab_grant_foreign_access_trans(domid_t domid, int flags,
+				      domid_t trans_domid,
+				      grant_ref_t trans_gref);
 
 /*
  * Are sub-page grants available on this version of Xen?  Returns true if they
@@ -73,6 +76,12 @@ int gnttab_grant_foreign_access_subpage(domid_t domid, unsigned long frame,
 bool gnttab_subpage_grants_available(void);
 
 /*
+ * Are transitive grants available on this version of Xen?  Returns true if they
+ * are, and false if they're not.
+ */
+bool gnttab_trans_grants_available(void);
+
+/*
  * End access through the given grant reference, iff the grant entry is no
  * longer in use.  Return 1 if the grant entry was freed, 0 if it is still in
  * use.
@@ -121,6 +130,9 @@ int gnttab_grant_foreign_access_subpage_ref(grant_ref_t ref, domid_t domid,
 					    unsigned long frame, int flags,
 					    unsigned page_off,
 					    unsigned length);
+int gnttab_grant_foreign_access_trans_ref(grant_ref_t ref, domid_t domid,
+					  int flags, domid_t trans_domid,
+					  grant_ref_t trans_gref);
 
 void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
 				       unsigned long pfn);