From patchwork Sun Jan 10 14:21:56 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 7996561 Return-Path: X-Original-To: patchwork-xen-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 1A2919F1C0 for ; Sun, 10 Jan 2016 14:24:30 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 4E1C02025B for ; Sun, 10 Jan 2016 14:24:29 +0000 (UTC) Received: from lists.xen.org (lists.xenproject.org [50.57.142.19]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9ACB12024D for ; Sun, 10 Jan 2016 14:24:27 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xen.org) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aIGsk-0002vd-BH; Sun, 10 Jan 2016 14:22:10 +0000 Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aIGsi-0002u3-Rk for xen-devel@lists.xenproject.org; Sun, 10 Jan 2016 14:22:08 +0000 Received: from [193.109.254.147] by server-13.bemta-14.messagelabs.com id 15/17-08347-01962965; Sun, 10 Jan 2016 14:22:08 +0000 X-Env-Sender: mst@redhat.com X-Msg-Ref: server-12.tower-27.messagelabs.com!1452435725!15733537!1 X-Originating-IP: [209.132.183.28] X-SpamReason: No, hits=0.0 required=7.0 tests=sa_preprocessor: VHJ1c3RlZCBJUDogMjA5LjEzMi4xODMuMjggPT4gNTQwNjQ=\n X-StarScan-Received: X-StarScan-Version: 7.35.1; banners=-,-,- X-VirusChecked: Checked Received: (qmail 59440 invoked from network); 10 Jan 2016 14:22:07 -0000 Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by server-12.tower-27.messagelabs.com with DHE-RSA-AES256-GCM-SHA384 encrypted SMTP; 10 Jan 2016 14:22:07 -0000 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id 42BA4C0BF2A7; Sun, 10 Jan 2016 14:22:05 +0000 (UTC) Received: from redhat.com (vpn1-5-155.ams2.redhat.com [10.36.5.155]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id u0AELumM032025; Sun, 10 Jan 2016 09:21:57 -0500 Date: Sun, 10 Jan 2016 16:21:56 +0200 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Message-ID: <1452426622-4471-40-git-send-email-mst@redhat.com> References: <1452426622-4471-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1452426622-4471-1-git-send-email-mst@redhat.com> X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 Cc: linux-mips@linux-mips.org, linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra , virtualization@lists.linux-foundation.org, Stefano Stabellini , "H. Peter Anvin" , sparclinux@vger.kernel.org, Boris Ostrovsky , linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, Russell King - ARM Linux , Arnd Bergmann , x86@kernel.org, xen-devel@lists.xenproject.org, Ingo Molnar , linux-xtensa@linux-xtensa.org, user-mode-linux-devel@lists.sourceforge.net, Stefano Stabellini , adi-buildroot-devel@lists.sourceforge.net, Thomas Gleixner , linux-metag@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Wei Liu , Andrew Cooper , Julien Grall , Ross Lagerwall , David Vrabel , Joe Perches , linuxppc-dev@lists.ozlabs.org, David Miller Subject: [Xen-devel] [PATCH v3 39/41] xen/events: use virt_xxx barriers X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP drivers/xen/events/events_fifo.c uses rmb() to communicate with the other side. For guests compiled with CONFIG_SMP, smp_rmb would be sufficient, so rmb() here is only needed if a non-SMP guest runs on an SMP host. Switch to the virt_rmb barrier which serves this exact purpose. Pull in asm/barrier.h here to make sure the file is self-contained. Suggested-by: David Vrabel Signed-off-by: Michael S. Tsirkin Acked-by: David Vrabel --- drivers/xen/events/events_fifo.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c index 96a1b8d..eff2b88 100644 --- a/drivers/xen/events/events_fifo.c +++ b/drivers/xen/events/events_fifo.c @@ -41,6 +41,7 @@ #include #include +#include #include #include #include @@ -296,7 +297,7 @@ static void consume_one_event(unsigned cpu, * control block. */ if (head == 0) { - rmb(); /* Ensure word is up-to-date before reading head. */ + virt_rmb(); /* Ensure word is up-to-date before reading head. */ head = control_block->head[priority]; }