[Xen-devel] [PATCH] Extra check in grant table code for mapping of shared frame

[Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>]

 xen/common/grant_table.c |  9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)


Signed-off-by: Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>

diff -r 5ce5b53ea68f -r 40b91bed1275 xen/common/grant_table.c
--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -649,9 +649,12 @@ __gnttab_map_grant_ref(
     }
     else if ( owner == rd || owner == dom_cow )
     {
-        if ( gnttab_host_mapping_get_page_type(op, ld, rd) &&
-             !get_page_type(pg, PGT_writable_page) )
-            goto could_not_pin;
+        if ( gnttab_host_mapping_get_page_type(op, ld, rd) )
+        {
+            if ( (owner == dom_cow) ||
+                 !get_page_type(pg, PGT_writable_page) )
+                goto could_not_pin;
+        }
 
         nr_gets++;
         if ( op->flags & GNTMAP_host_map )

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