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=-16.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 9D3E2C432BE for ; Tue, 24 Aug 2021 00:55:39 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (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 67CB3617E3 for ; Tue, 24 Aug 2021 00:55:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 67CB3617E3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 4087980C49; Tue, 24 Aug 2021 00:55:39 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id y6xoLvvtVILH; Tue, 24 Aug 2021 00:55:35 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp1.osuosl.org (Postfix) with ESMTPS id C773880C1E; Tue, 24 Aug 2021 00:55:34 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id B189BC0010; Tue, 24 Aug 2021 00:55:34 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id CD89CC001F for ; Tue, 24 Aug 2021 00:55:33 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id CAD816080C for ; Tue, 24 Aug 2021 00:55:33 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp3.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=kernel.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id oP2cailIOJzm for ; Tue, 24 Aug 2021 00:55:33 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp3.osuosl.org (Postfix) with ESMTPS id 214C4607F2 for ; Tue, 24 Aug 2021 00:55:33 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id D06B361465; Tue, 24 Aug 2021 00:55:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629766532; bh=IA1WmkjigDlNNXQ3GGsHPcOTbnznmk/3qaJq+F/q3dM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T3uFRCeWVbD21uvcx+xdsawL6TKjBL+PTEjHy8skLh3ikbi0oyM4tfK+blImcPiRW 2YErLzXUPqUhdI1qLvHfbWpFZW1Sw5qET6DUia1/rEaFR67PIs6bC3vZNUSJ837M+U Vlji8Bn79eJAnX424sU32RFaU2itZYP327ENqh6DEkseXV/ArRFrXc8I+htsttKr+g QcApkIbCpNOGn73GiY3ARaxXnzKhoEEeRyz6tvBHhnJpn2XGQeAcrMsSovKBvCj1rE Qkc0jPZIMJFMoew2ckU51pAqistCt99eI0iP6rYZSxaKgdI1TrDwYfBvumhaoli9VG c2QXS8oowatoQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH AUTOSEL 4.14 3/7] vringh: Use wiov->used to check for read/write desc order Date: Mon, 23 Aug 2021 20:55:24 -0400 Message-Id: <20210824005528.631702-3-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210824005528.631702-1-sashal@kernel.org> References: <20210824005528.631702-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Cc: Sasha Levin , kvm@vger.kernel.org, "Michael S . Tsirkin" , netdev@vger.kernel.org, virtualization@lists.linux-foundation.org, Neeraj Upadhyay X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" From: Neeraj Upadhyay [ Upstream commit e74cfa91f42c50f7f649b0eca46aa049754ccdbd ] As __vringh_iov() traverses a descriptor chain, it populates each descriptor entry into either read or write vring iov and increments that iov's ->used member. So, as we iterate over a descriptor chain, at any point, (riov/wriov)->used value gives the number of descriptor enteries available, which are to be read or written by the device. As all read iovs must precede the write iovs, wiov->used should be zero when we are traversing a read descriptor. Current code checks for wiov->i, to figure out whether any previous entry in the current descriptor chain was a write descriptor. However, iov->i is only incremented, when these vring iovs are consumed, at a later point, and remain 0 in __vringh_iov(). So, correct the check for read and write descriptor order, to use wiov->used. Acked-by: Jason Wang Reviewed-by: Stefano Garzarella Signed-off-by: Neeraj Upadhyay Link: https://lore.kernel.org/r/1624591502-4827-1-git-send-email-neeraju@codeaurora.org Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin --- drivers/vhost/vringh.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c index 1e2e01270be9..c23045aa9873 100644 --- a/drivers/vhost/vringh.c +++ b/drivers/vhost/vringh.c @@ -330,7 +330,7 @@ __vringh_iov(struct vringh *vrh, u16 i, iov = wiov; else { iov = riov; - if (unlikely(wiov && wiov->i)) { + if (unlikely(wiov && wiov->used)) { vringh_bad("Readable desc %p after writable", &descs[i]); err = -EINVAL; -- 2.30.2 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization