1 files changed, 42 insertions, 0 deletions
diff --git a/system/xen/xsa/xsa224-0002-gnttab-never-create-host-mapping-unless-asked-to.patch b/system/xen/xsa/xsa224-0002-gnttab-never-create-host-mapping-unless-asked-to.patch
new file mode 100644
index 0000000000..bea0214db0
--- /dev/null
+++ b/system/xen/xsa/xsa224-0002-gnttab-never-create-host-mapping-unless-asked-to.patch
@@ -0,0 +1,42 @@
+From 2d6357522946bd5a105066db8079e5dd46cb3047 Mon Sep 17 00:00:00 2001
+From: Jan Beulich <jbeulich@suse.com>
+Date: Fri, 2 Jun 2017 15:21:27 +0100
+Subject: [PATCH 2/4] gnttab: never create host mapping unless asked to
+
+We shouldn't create a host mapping unless asked to even in the case of
+mapping a granted MMIO page. In particular the mapping wouldn't be torn
+down when processing the matching unmap request.
+
+This is part of XSA-224.
+
+Reported-by: Jan Beulich <jbeulich@suse.com>
+Signed-off-by: Jan Beulich <jbeulich@suse.com>
+---
+ xen/common/grant_table.c | 11 +++++++----
+ 1 file changed, 7 insertions(+), 4 deletions(-)
+
+diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
+index 2671761..5baae24 100644
+--- a/xen/common/grant_table.c
++++ b/xen/common/grant_table.c
+@@ -907,10 +907,13 @@ __gnttab_map_grant_ref(
+             goto undo_out;
+         }
+ 
+-        rc = create_grant_host_mapping(
+-            op->host_addr, frame, op->flags, cache_flags);
+-        if ( rc != GNTST_okay )
+-            goto undo_out;
++        if ( op->flags & GNTMAP_host_map )
++        {
++            rc = create_grant_host_mapping(op->host_addr, frame, op->flags,
++                                           cache_flags);
++            if ( rc != GNTST_okay )
++                goto undo_out;
++        }
+     }
+     else if ( owner == rd || owner == dom_cow )
+     {
+-- 
+2.1.4
+