From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-7346-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 1C091986048 for ; Fri, 15 May 2020 10:14:28 +0000 (UTC) From: David Hildenbrand 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 Subject: [virtio-dev] [PATCH v4 16/15] virtio-mem: Don't rely on implicit compiler padding for requests Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable 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 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 *vde= v) =09struct virtio_mem *vm; =09int rc =3D -EINVAL; =20 +=09BUILD_BUG_ON(sizeof(struct virtio_mem_req) !=3D 24); +=09BUILD_BUG_ON(sizeof(struct virtio_mem_resp) !=3D 10); + =09vdev->priv =3D vm =3D kzalloc(sizeof(*vm), GFP_KERNEL); =09if (!vm) =09=09return -ENOMEM; diff --git a/include/uapi/linux/virtio_mem.h b/include/uapi/linux/virtio_me= m.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 { =09__virtio64 addr; =09__virtio16 nb_blocks; +=09__virtio16 padding[3]; }; =20 struct virtio_mem_req_unplug { =09__virtio64 addr; =09__virtio16 nb_blocks; +=09__virtio16 padding[3]; }; =20 struct virtio_mem_req_state { =09__virtio64 addr; =09__virtio16 nb_blocks; +=09__virtio16 padding[3]; }; =20 struct virtio_mem_req { --=20 2.25.4 --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org