From patchwork Fri Feb 19 15:40:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 12095673 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=-18.8 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=ham 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 97E8FC433E0 for ; Fri, 19 Feb 2021 15:41:01 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4E51564DFD for ; Fri, 19 Feb 2021 15:41:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4E51564DFD Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.86935.163595 (Exim 4.92) (envelope-from ) id 1lD7tk-0002R3-FH; Fri, 19 Feb 2021 15:40:52 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 86935.163595; Fri, 19 Feb 2021 15:40:52 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lD7tk-0002Qo-7w; Fri, 19 Feb 2021 15:40:52 +0000 Received: by outflank-mailman (input) for mailman id 86935; Fri, 19 Feb 2021 15:40:50 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lD7th-0002F7-Vq for xen-devel@lists.xenproject.org; Fri, 19 Feb 2021 15:40:50 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 17195ed2-3ee0-4ae2-ad36-57118e02a687; Fri, 19 Feb 2021 15:40:40 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 8FC36B114; Fri, 19 Feb 2021 15:40:39 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 17195ed2-3ee0-4ae2-ad36-57118e02a687 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=1613749239; 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=mqlyaLZe/YgvYSsQIvPpN9XoaMOuiHW3Pbur9d3Wz3NOMHY4Oy4s66u3aQWq9fxarixX/O Ey3afn8U9k0KK6JKqUCXGc1zWME5EppFL1W/JOkfTp3ilVzkPrWMZUrxql+Y+EqqtO2aWl dpSxPChifLttkm90i7WQkWP8NL1KFr4= 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 v3 7/8] xen/evtchn: use smp barriers for user event ring Date: Fri, 19 Feb 2021 16:40:29 +0100 Message-Id: <20210219154030.10892-8-jgross@suse.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210219154030.10892-1-jgross@suse.com> References: <20210219154030.10892-1-jgross@suse.com> MIME-Version: 1.0 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)))