Merge remote-tracking branch 'remotes/sstabellini/tags/xen-2016-04-20' into staging

Xen 2016/04/20

# gpg: Signature made Wed 20 Apr 2016 12:08:56 BST using RSA key ID 70E1AE90
# gpg: Good signature from "Stefano Stabellini <stefano.stabellini@eu.citrix.com>"

* remotes/sstabellini/tags/xen-2016-04-20:
  xenfb: use the correct condition to avoid excessive looping
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

hw/display/xenfb.c

@@ -775,7 +775,7 @@ static void xenfb_handle_events(struct XenFB *xenfb)
 
     prod = page->out_prod;
     out_cons = page->out_cons;
-    if (prod - out_cons >= XENFB_OUT_RING_LEN) {
+    if (prod - out_cons > XENFB_OUT_RING_LEN) {
         return;
     }
     xen_rmb();		/* ensure we see ring contents up to prod */