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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E3DBC433F5 for ; Thu, 11 Nov 2021 06:48:57 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 B309261037 for ; Thu, 11 Nov 2021 06:48:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org B309261037 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:43722 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ml3tH-0003aV-Av for qemu-devel@archiver.kernel.org; Thu, 11 Nov 2021 01:48:55 -0500 Received: from eggs.gnu.org ([209.51.188.92]:54764) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ml3jw-0000sq-1z for qemu-devel@nongnu.org; Thu, 11 Nov 2021 01:39:17 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:58782) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ml3jt-0008GG-6Z for qemu-devel@nongnu.org; Thu, 11 Nov 2021 01:39:14 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636612752; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=b8spEDa3CYNdZ+VDWEhG2bwDPPSg8IVxjxOBYMsBUME=; b=A2VoFsy8EYtZlaxs3UAveXV9Jr+EOfIrn5iQaHpL7BCxC6c5xMzwDP6rhnRZY/YvxtuuB+ ziohH80V563T/Bx90zSw4VV0+PDkDee/sk6884pyjezBj1gc5UVik2zZGg5R1VsZPLXdk7 Gd78FPtrPITSrE1K5j7SM68ejQYf+j4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-473-p6wD8h1IMVSKtkD5gA1mHw-1; Thu, 11 Nov 2021 01:39:09 -0500 X-MC-Unique: p6wD8h1IMVSKtkD5gA1mHw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 616BA802EDA; Thu, 11 Nov 2021 06:39:08 +0000 (UTC) Received: from localhost.localdomain (ovpn-13-246.pek2.redhat.com [10.72.13.246]) by smtp.corp.redhat.com (Postfix) with ESMTP id A9E855BAE2; Thu, 11 Nov 2021 06:39:06 +0000 (UTC) From: Jason Wang To: mst@redhat.com Subject: [PATCH 2/2] virtio: use virtio accessor to access packed event Date: Thu, 11 Nov 2021 14:38:54 +0800 Message-Id: <20211111063854.29060-2-jasowang@redhat.com> In-Reply-To: <20211111063854.29060-1-jasowang@redhat.com> References: <20211111063854.29060-1-jasowang@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jasowang@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=216.205.24.124; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.7, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: eperezma@redhat.com, Jason Wang , qemu-devel@nongnu.org, qemu-stable@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" We used to access packed descriptor event and off_wrap via address_space_{write|read}_cached(). When we hit the cache, memcpy() is used which is not atomic which may lead a wrong value to be read or wrote. This patch fixes this by switching to use virito_{stw|lduw}_phys_cached() to make sure the access is atomic. Fixes: 683f7665679c1 ("virtio: event suppression support for packed ring") Cc: qemu-stable@nongnu.org Signed-off-by: Jason Wang --- hw/virtio/virtio.c | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 939bcbfeb9..ea7c079fb0 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -247,13 +247,10 @@ static void vring_packed_event_read(VirtIODevice *vdev, hwaddr off_off = offsetof(VRingPackedDescEvent, off_wrap); hwaddr off_flags = offsetof(VRingPackedDescEvent, flags); - address_space_read_cached(cache, off_flags, &e->flags, - sizeof(e->flags)); + e->flags = virtio_lduw_phys_cached(vdev, cache, off_flags); /* Make sure flags is seen before off_wrap */ smp_rmb(); - address_space_read_cached(cache, off_off, &e->off_wrap, - sizeof(e->off_wrap)); - virtio_tswap16s(vdev, &e->off_wrap); + e->off_wrap = virtio_lduw_phys_cached(vdev, cache, off_off); virtio_tswap16s(vdev, &e->flags); } @@ -263,8 +260,7 @@ static void vring_packed_off_wrap_write(VirtIODevice *vdev, { hwaddr off = offsetof(VRingPackedDescEvent, off_wrap); - virtio_tswap16s(vdev, &off_wrap); - address_space_write_cached(cache, off, &off_wrap, sizeof(off_wrap)); + virtio_stw_phys_cached(vdev, cache, off, off_wrap); address_space_cache_invalidate(cache, off, sizeof(off_wrap)); } @@ -273,8 +269,7 @@ static void vring_packed_flags_write(VirtIODevice *vdev, { hwaddr off = offsetof(VRingPackedDescEvent, flags); - virtio_tswap16s(vdev, &flags); - address_space_write_cached(cache, off, &flags, sizeof(flags)); + virtio_stw_phys_cached(vdev, cache, off, flags); address_space_cache_invalidate(cache, off, sizeof(flags)); } -- 2.25.1