From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C4751C433E0 for ; Thu, 11 Feb 2021 10:27:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 925B864DB2 for ; Thu, 11 Feb 2021 10:27:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229997AbhBKK1V (ORCPT ); Thu, 11 Feb 2021 05:27:21 -0500 Received: from mx2.suse.de ([195.135.220.15]:42450 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229919AbhBKKVN (ORCPT ); Thu, 11 Feb 2021 05:21:13 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1613038661; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nYiBLOOS0jKaGXZR/xdp5WHTi+5sOW1v2m88NDrZNbI=; b=LmkY0cY/xUPQabBZ2K6py6iwlNSohSvZqtVGIKhgfs/Vd+e3i0HPowZRhK5GJgyUl5o28/ Lx47YRJ3EXvR1/z8sPJDmrvUc6rf00u386Gf1+f8cdN9vhlSbjkIEU7foEmfSwD4BZQf/a zldb9aBFKnXvuTux4U/p6Gw35AZbFbs= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 6FD2CAF49; Thu, 11 Feb 2021 10:17:41 +0000 (UTC) From: Juergen Gross To: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Cc: Juergen Gross , Boris Ostrovsky , Stefano Stabellini , Andrew Cooper , Jan Beulich Subject: [PATCH v2 7/8] xen/evtch: use smp barriers for user event ring Date: Thu, 11 Feb 2021 11:16:15 +0100 Message-Id: <20210211101616.13788-8-jgross@suse.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210211101616.13788-1-jgross@suse.com> References: <20210211101616.13788-1-jgross@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The ring buffer for user events is local to the given kernel instance, so smp barriers are fine for ensuring consistency. Reported-by: Andrew Cooper Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich --- drivers/xen/evtchn.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c index a7a85719a8c8..421382c73d88 100644 --- a/drivers/xen/evtchn.c +++ b/drivers/xen/evtchn.c @@ -173,7 +173,7 @@ static irqreturn_t evtchn_interrupt(int irq, void *data) if ((u->ring_prod - u->ring_cons) < u->ring_size) { *evtchn_ring_entry(u, u->ring_prod) = evtchn->port; - wmb(); /* Ensure ring contents visible */ + smp_wmb(); /* Ensure ring contents visible */ if (u->ring_cons == u->ring_prod++) { wake_up_interruptible(&u->evtchn_wait); kill_fasync(&u->evtchn_async_queue, @@ -245,7 +245,7 @@ static ssize_t evtchn_read(struct file *file, char __user *buf, } rc = -EFAULT; - rmb(); /* Ensure that we see the port before we copy it. */ + smp_rmb(); /* Ensure that we see the port before we copy it. */ if (copy_to_user(buf, evtchn_ring_entry(u, c), bytes1) || ((bytes2 != 0) && copy_to_user(&buf[bytes1], &u->ring[0], bytes2))) -- 2.26.2