[src/trunk]: src/sys/arch/xen/xen xengnt(4): Membar audit.

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/7fefbfbf02f0
branches:  trunk
changeset: 373717:7fefbfbf02f0
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sat Feb 25 00:33:50 2023 +0000

description:
xengnt(4): Membar audit.

This had the sense of membars reversed, presumably because xen_rmb
and xen_wmb had gotten reversed at some point.

diffstat:

 sys/arch/xen/xen/xengnt.c |  10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diffs (38 lines):

diff -r c079ec2a886f -r 7fefbfbf02f0 sys/arch/xen/xen/xengnt.c
--- a/sys/arch/xen/xen/xengnt.c Sat Feb 25 00:33:38 2023 +0000
+++ b/sys/arch/xen/xen/xengnt.c Sat Feb 25 00:33:50 2023 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: xengnt.c,v 1.39 2022/06/03 10:42:17 bouyer Exp $      */
+/*      $NetBSD: xengnt.c,v 1.40 2023/02/25 00:33:50 riastradh Exp $      */
 
 /*
  * Copyright (c) 2006 Manuel Bouyer.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xengnt.c,v 1.39 2022/06/03 10:42:17 bouyer Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xengnt.c,v 1.40 2023/02/25 00:33:50 riastradh Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -453,7 +453,7 @@
                 * ensure that the above values reach global visibility 
                 * before permitting frame's access (done when we set flags)
                 */
-               xen_rmb();
+               xen_wmb();
                grant_table.gntt_v2[*entryp].hdr.flags =
                    GTF_permit_access | (ro ? GTF_readonly : 0);
        } else {
@@ -463,8 +463,8 @@
                * ensure that the above values reach global visibility
                * before permitting frame's access (done when we set flags)    
                */
-               xen_rmb();
-               grant_table.gntt_v1[*entryp].flags =  
+               xen_wmb();
+               grant_table.gntt_v1[*entryp].flags =
                   GTF_permit_access | (ro ? GTF_readonly : 0);
        }
        mutex_exit(&grant_lock);