[Xen-changelog] [xen-3.0-testing] [XEN] Fix domid check in grant tables when re-using an already pinned grant

[Xen patchbot-3.0-testing <patchbot-3.0-testing@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User ssmith@xxxxxxxxxxxxxxxxxxxxxxxxxx
# Node ID 662dcf03872df750e092e25e7e3beaae15e991b7
# Parent  1e225598ce827a8d810ad57e82547ad6ed9c0258
[XEN] Fix domid check in grant tables when re-using an already pinned grant
table entry.

Based on cset 11419 in xen-unstable, originally from Herbert Xu.

Signed-off-by: Steven Smith <sos22@xxxxxxxxx>
---
 xen/common/grant_table.c |   11 ++++++++---
 1 files changed, 8 insertions(+), 3 deletions(-)

diff -r 1e225598ce82 -r 662dcf03872d xen/common/grant_table.c
--- a/xen/common/grant_table.c  Thu Jun 29 10:51:49 2006 +0100
+++ b/xen/common/grant_table.c  Thu Sep 07 10:08:25 2006 +0100
@@ -163,6 +163,14 @@ __gnttab_map_grant_ref(
 
     spin_lock(&rd->grant_table->lock);
 
+    /* If already pinned, check the active domid and avoid refcnt overflow. */
+    if ( act->pin &&
+         ((act->domid != ld->domain_id) ||
+          (act->pin & 0x80808080U) != 0) )
+        PIN_FAIL(unlock_out, GNTST_general_error,
+                 "Bad domain (%d != %d), or risk of counter overflow %08x\n",
+                 act->domid, ld->domain_id, act->pin);
+
     if ( !act->pin ||
          (!(op->flags & GNTMAP_readonly) &&
           !(act->pin & (GNTPIN_hstw_mask|GNTPIN_devw_mask))) )
@@ -221,9 +229,6 @@ __gnttab_map_grant_ref(
             act->frame = gmfn_to_mfn(rd, sha->frame);
         }
     }
-    else if ( (act->pin & 0x80808080U) != 0 )
-        PIN_FAIL(unlock_out, ENOSPC,
-                 "Risk of counter overflow %08x\n", act->pin);
 
     if ( op->flags & GNTMAP_device_map )
         act->pin += (op->flags & GNTMAP_readonly) ?

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog