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=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 0F358C433E1 for ; Fri, 15 May 2020 10:14:28 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A9A622073E for ; Fri, 15 May 2020 10:14:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Etbk/Aq/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A9A622073E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id ECB938E0008; Fri, 15 May 2020 06:14:26 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E7C318E0005; Fri, 15 May 2020 06:14:26 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D69118E0008; Fri, 15 May 2020 06:14:26 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0183.hostedemail.com [216.40.44.183]) by kanga.kvack.org (Postfix) with ESMTP id BBFAA8E0005 for ; Fri, 15 May 2020 06:14:26 -0400 (EDT) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 71AD5181AEF00 for ; Fri, 15 May 2020 10:14:26 +0000 (UTC) X-FDA: 76818543732.06.chair48_60eb3af269d3d X-HE-Tag: chair48_60eb3af269d3d X-Filterd-Recvd-Size: 4064 Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) by imf32.hostedemail.com (Postfix) with ESMTP for ; Fri, 15 May 2020 10:14:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589537665; h=from:from:reply-to:subject:subject: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=lUc3PuOX813Luq3FUqNVTnGhB/o6E0eeOYPacW9Z1Gk=; b=Etbk/Aq/HDlE8LdSj/DGBgE0ypMARfAV9zNCAiCPvt3RZ0WtJN0sKz+iV0zaIZ2YSOALYa sweKMYLiSugGvhrIQHlrnIjEIBu5Va0khCAdOfhua92/sRO430mStfu04ADPtmdAZlDhVo eea14aUxpAdNGr+BzZPZdmVUBEis1x0= 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-142-t0_WzsGWPv2-7atizBRpXg-1; Fri, 15 May 2020 06:14:23 -0400 X-MC-Unique: t0_WzsGWPv2-7atizBRpXg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 55031835B44; Fri, 15 May 2020 10:14:21 +0000 (UTC) Received: from t480s.redhat.com (ovpn-114-77.ams2.redhat.com [10.36.114.77]) by smtp.corp.redhat.com (Postfix) with ESMTP id BA02360FB9; Fri, 15 May 2020 10:14:12 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, virtio-dev@lists.oasis-open.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, Michal Hocko , Andrew Morton , "Michael S . Tsirkin" , David Hildenbrand , Pankaj Gupta , teawater Subject: [PATCH v4 16/15] virtio-mem: Don't rely on implicit compiler padding for requests Date: Fri, 15 May 2020 12:14:02 +0200 Message-Id: <20200515101402.16597-1-david@redhat.com> In-Reply-To: <20200507140139.17083-1-david@redhat.com> References: <20200507140139.17083-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: The compiler will add padding after the last member, make that explicit. The size of a request is always 24 bytes. The size of a response always 10 bytes. Add compile-time checks. Cc: "Michael S. Tsirkin" Cc: Pankaj Gupta Cc: teawater Signed-off-by: David Hildenbrand --- Something I noticed while working on the spec (which proves that writing = a virtio-spec makes sense :) ). --- drivers/virtio/virtio_mem.c | 3 +++ include/uapi/linux/virtio_mem.h | 3 +++ 2 files changed, 6 insertions(+) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index 9e523db3bee1..f658fe9149be 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -1770,6 +1770,9 @@ static int virtio_mem_probe(struct virtio_device *v= dev) struct virtio_mem *vm; int rc =3D -EINVAL; =20 + BUILD_BUG_ON(sizeof(struct virtio_mem_req) !=3D 24); + BUILD_BUG_ON(sizeof(struct virtio_mem_resp) !=3D 10); + vdev->priv =3D vm =3D kzalloc(sizeof(*vm), GFP_KERNEL); if (!vm) return -ENOMEM; diff --git a/include/uapi/linux/virtio_mem.h b/include/uapi/linux/virtio_= mem.h index e0a9dc7397c3..a455c488a995 100644 --- a/include/uapi/linux/virtio_mem.h +++ b/include/uapi/linux/virtio_mem.h @@ -103,16 +103,19 @@ struct virtio_mem_req_plug { __virtio64 addr; __virtio16 nb_blocks; + __virtio16 padding[3]; }; =20 struct virtio_mem_req_unplug { __virtio64 addr; __virtio16 nb_blocks; + __virtio16 padding[3]; }; =20 struct virtio_mem_req_state { __virtio64 addr; __virtio16 nb_blocks; + __virtio16 padding[3]; }; =20 struct virtio_mem_req { --=20 2.25.4