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 20ED0C433EF for ; Thu, 11 Nov 2021 06:48:58 +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 8C58361269 for ; Thu, 11 Nov 2021 06:48:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 8C58361269 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]:43740 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ml3tH-0003b1-Gi for qemu-devel@archiver.kernel.org; Thu, 11 Nov 2021 01:48:56 -0500 Received: from eggs.gnu.org ([209.51.188.92]:54744) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ml3js-0000sh-CU for qemu-devel@nongnu.org; Thu, 11 Nov 2021 01:39:15 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:47071) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ml3jq-0008Ft-N8 for qemu-devel@nongnu.org; Thu, 11 Nov 2021 01:39:12 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636612750; 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; bh=kWSUrwZ7tiWatmlaYo9vEoa+Sde7ZP+BgfRnQ7YbszA=; b=bBF0Zwct+wLE7xh+GU/d7Uff/vGibSEJE1iWo/59t0+e0SjuosXAMpSckqGtYFTmoT1wr1 chOKMNZJgDrJ93aH+ZIwxAGtJfKIbj0sd97+G+dSglFrOTbfKf24jpvIaA6w7s1OSg33j+ WDyqWElZ+Qef+c8oq+ku5Gsi4TSlNR0= 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-200-lXBynJnOPEGbsygkvOH4MA-1; Thu, 11 Nov 2021 01:39:07 -0500 X-MC-Unique: lXBynJnOPEGbsygkvOH4MA-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 36A1015720; Thu, 11 Nov 2021 06:39:06 +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 927FE608BA; Thu, 11 Nov 2021 06:38:56 +0000 (UTC) From: Jason Wang To: mst@redhat.com Subject: [PATCH 1/2] virtio: use virtio accessor to access packed descriptor flags Date: Thu, 11 Nov 2021 14:38:53 +0800 Message-Id: <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=170.10.133.124; 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 flags via address_space_{write|read}_cached(). When we hit the cache, memcpy() is used which is not an atomic operation which may lead a wrong value is read or wrote. So this patch switches to use virito_{stw|lduw}_phys_cached() to make sure the aceess is atomic. Fixes: 86044b24e865f ("virtio: basic packed virtqueue support") Cc: qemu-stable@nongnu.org Signed-off-by: Jason Wang --- hw/virtio/virtio.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index cc69a9b881..939bcbfeb9 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -507,11 +507,9 @@ static void vring_packed_desc_read_flags(VirtIODevice *vdev, MemoryRegionCache *cache, int i) { - address_space_read_cached(cache, - i * sizeof(VRingPackedDesc) + - offsetof(VRingPackedDesc, flags), - flags, sizeof(*flags)); - virtio_tswap16s(vdev, flags); + hwaddr off = i * sizeof(VRingPackedDesc) + offsetof(VRingPackedDesc, flags); + + *flags = virtio_lduw_phys_cached(vdev, cache, off); } static void vring_packed_desc_read(VirtIODevice *vdev, @@ -564,8 +562,7 @@ static void vring_packed_desc_write_flags(VirtIODevice *vdev, { hwaddr off = i * sizeof(VRingPackedDesc) + offsetof(VRingPackedDesc, flags); - virtio_tswap16s(vdev, &desc->flags); - address_space_write_cached(cache, off, &desc->flags, sizeof(desc->flags)); + virtio_stw_phys_cached(vdev, cache, off, desc->flags); address_space_cache_invalidate(cache, off, sizeof(desc->flags)); } -- 2.25.1