diff -r 08e2c03a47e0 xen/common/grant_table.c
--- a/xen/common/grant_table.c	Tue May 15 17:47:46 2007 +0100
+++ b/xen/common/grant_table.c	Thu May 17 09:53:29 2007 +0100
@@ -195,7 +195,9 @@ __gnttab_map_grant_ref(
     led = current;
     ld = led->domain;
 
-    if ( unlikely((op->flags & (GNTMAP_device_map|GNTMAP_host_map)) == 0) )
+    if ( unlikely((op->flags & (GNTMAP_device_map |
+                                GNTMAP_host_map | 
+                                GNTMAP_iomem_map)) == 0) )
     {
         gdprintk(XENLOG_INFO, "Bad flags in grant map op (%x).\n", op->flags);
         op->status = GNTST_bad_gntref;
@@ -305,16 +307,36 @@ __gnttab_map_grant_ref(
 
     spin_unlock(&rd->grant_table->lock);
 
-    if ( unlikely(!mfn_valid(frame)) ||
-         unlikely(!((op->flags & GNTMAP_readonly) ?
-                    get_page(mfn_to_page(frame), rd) :
-                    get_page_and_type(mfn_to_page(frame), rd,
-                                      PGT_writable_page))) )
-    {
-        if ( !rd->is_dying )
-            gdprintk(XENLOG_WARNING, "Could not pin grant frame %lx\n", frame);
-        rc = GNTST_general_error;
-        goto undo_out;
+    if ( op->flags & GNTMAP_iomem_map )
+    {
+        if( op->dom == 0 && !mfn_valid(frame) ) {
+            /* Could be an iomem page for setting up permission */
+            if ( iomem_permit_access(ld, frame, frame) != 0 ) {
+                gdprintk(XENLOG_WARNING, 
+                         "Could not permit access to grant frame %lx as iomem\n",
+                         frame);
+                rc = GNTST_general_error;
+                goto undo_out;
+            }
+        } else {
+            gdprintk(XENLOG_WARNING, 
+                     "Invalid domain (%d) or frame (%lx) for iomem map\n",
+                     op->dom, frame);
+            rc = GNTST_general_error;
+            goto undo_out;
+        }
+    } else {
+        if ( unlikely(!mfn_valid(frame)) ||
+             unlikely(!((op->flags & GNTMAP_readonly) ?
+                        get_page(mfn_to_page(frame), rd) :
+                        get_page_and_type(mfn_to_page(frame), rd,
+                                          PGT_writable_page))) )
+        {
+            if ( !rd->is_dying )
+                gdprintk(XENLOG_WARNING, "Could not pin grant frame %lx\n", frame);
+            rc = GNTST_general_error;
+            goto undo_out;
+        }
     }
 
     if ( op->flags & GNTMAP_host_map )
@@ -494,8 +516,17 @@ __gnttab_unmap_grant_ref(
             put_page_and_type(mfn_to_page(frame));
         }
     }
-
-    if ( (map->flags & (GNTMAP_device_map|GNTMAP_host_map)) == 0 )
+    
+    if ( flags & GNTMAP_iomem_map ) 
+    {
+        map->flags &= ~GNTMAP_iomem_map;
+
+        rc = iomem_deny_access(ld, frame, frame);
+    }
+
+    if ( (map->flags & (GNTMAP_device_map |
+                        GNTMAP_host_map |
+                        GNTMAP_iomem_map)) == 0 )
     {
         map->flags = 0;
         put_maptrack_handle(ld->grant_table, op->handle);
@@ -1352,13 +1383,16 @@ gnttab_release_mappings(
     struct domain        *rd;
     struct active_grant_entry *act;
     struct grant_entry   *sha;
+    int rc;
 
     BUG_ON(!d->is_dying);
 
     for ( handle = 0; handle < gt->maptrack_limit; handle++ )
     {
         map = &maptrack_entry(gt, handle);
-        if ( !(map->flags & (GNTMAP_device_map|GNTMAP_host_map)) )
+        if ( !(map->flags & (GNTMAP_device_map |
+                             GNTMAP_host_map |
+                             GNTMAP_iomem_map)) )
             continue;
 
         ref = map->ref;
@@ -1415,6 +1449,9 @@ gnttab_release_mappings(
             if ( (act->pin & (GNTPIN_devw_mask|GNTPIN_hstw_mask)) == 0 )
                 gnttab_clear_flag(_GTF_writing, &sha->flags);
         }
+
+        if( map->flags & GNTMAP_iomem_map )
+            rc = iomem_deny_access(rd, act->frame, act->frame);
 
         if ( act->pin == 0 )
             gnttab_clear_flag(_GTF_reading, &sha->flags);
diff -r 08e2c03a47e0 xen/include/public/grant_table.h
--- a/xen/include/public/grant_table.h	Tue May 15 17:47:46 2007 +0100
+++ b/xen/include/public/grant_table.h	Thu May 17 09:53:29 2007 +0100
@@ -358,6 +358,12 @@ DEFINE_XEN_GUEST_HANDLE(gnttab_query_siz
 #define GNTMAP_contains_pte     (1<<_GNTMAP_contains_pte)
 
 /*
+ * Establish iomem permission
+ */
+#define _GNTMAP_iomem_map       (5)
+#define GNTMAP_iomem_map       (1<<_GNTMAP_iomem_map)
+
+/*
  * Values for error status returns. All errors are -ve.
  */
 #define GNTST_okay             (0)  /* Normal return.                        */