diff --git a/sys/arch/xen/xen/xenevt.c b/sys/arch/xen/xen/xenevt.c
index 4effba9befe51..a8671858f51c7 100644
--- a/sys/arch/xen/xen/xenevt.c
+++ b/sys/arch/xen/xen/xenevt.c
@@ -1,4 +1,4 @@
-/*      $NetBSD: xenevt.c,v 1.29.4.2 2009/09/30 00:08:03 snj Exp $      */
+/*      $NetBSD: xenevt.c,v 1.29.4.2.6.1 2015/05/22 11:44:25 sborrill Exp $      */
 
 /*
  * Copyright (c) 2005 Manuel Bouyer.
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xenevt.c,v 1.29.4.2 2009/09/30 00:08:03 snj Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xenevt.c,v 1.29.4.2.6.1 2015/05/22 11:44:25 sborrill Exp $");
 
 #include "opt_xen.h"
 #include <sys/param.h>
@@ -496,7 +496,7 @@ xenevt_fwrite(struct file *fp, off_t *offp, struct uio *uio,
 	if (uio->uio_resid == 0)
 		return (0);
 	nentries = uio->uio_resid / sizeof(uint16_t);
-	if (nentries > NR_EVENT_CHANNELS)
+	if (nentries >= NR_EVENT_CHANNELS)
 		return EMSGSIZE;
 	chans = kmem_alloc(nentries * sizeof(uint16_t), KM_SLEEP);
 	if (chans == NULL)
@@ -580,7 +580,7 @@ xenevt_fioctl(struct file *fp, u_long cmd, void *addr)
 	{
 		struct ioctl_evtchn_unbind *unbind = addr;
 		
-		if (unbind->port > NR_EVENT_CHANNELS)
+		if (unbind->port >= NR_EVENT_CHANNELS)
 			return EINVAL;
 		if (devevent[unbind->port] != d)
 			return ENOTCONN;
@@ -596,7 +596,7 @@ xenevt_fioctl(struct file *fp, u_long cmd, void *addr)
 	{
 		struct ioctl_evtchn_notify *notify = addr;
 		
-		if (notify->port > NR_EVENT_CHANNELS)
+		if (notify->port >= NR_EVENT_CHANNELS)
 			return EINVAL;
 		if (devevent[notify->port] != d)
 			return ENOTCONN;