1 files changed, 46 insertions, 0 deletions

diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 6c4531816496..9ef54ebc1194 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -447,6 +447,52 @@ unsigned int gnttab_max_grant_frames(void)
 }
 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
 
+int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
+                    struct page **pages, unsigned int count)
+{
+        int i, ret;
+        pte_t *pte;
+        unsigned long mfn;
+
+        ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
+        if (ret)
+                return ret;
+
+        for (i = 0; i < count; i++) {
+                /* m2p override only supported for GNTMAP_contains_pte mappings */
+                if (!(map_ops[i].flags & GNTMAP_contains_pte))
+                        continue;
+                pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
+                                (map_ops[i].host_addr & ~PAGE_MASK));
+                mfn = pte_mfn(*pte);
+                ret = m2p_add_override(mfn, pages[i]);
+                if (ret)
+                        return ret;
+        }
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(gnttab_map_refs);
+
+int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
+                struct page **pages, unsigned int count)
+{
+        int i, ret;
+
+        ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
+        if (ret)
+                return ret;
+
+        for (i = 0; i < count; i++) {
+                ret = m2p_remove_override(pages[i]);
+                if (ret)
+                        return ret;
+        }
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
+
 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
 {
         struct gnttab_setup_table setup;