From patchwork Tue Sep 25 11:12:35 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 186773 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id E78382C0089 for ; Tue, 25 Sep 2012 21:12:07 +1000 (EST) Received: from localhost ([::1]:39598 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TGT3d-0002ds-R7 for incoming@patchwork.ozlabs.org; Tue, 25 Sep 2012 07:12:05 -0400 Received: from eggs.gnu.org ([208.118.235.92]:47664) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TGT2r-0001M2-8b for qemu-devel@nongnu.org; Tue, 25 Sep 2012 07:11:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TGT2q-0002sJ-2z for qemu-devel@nongnu.org; Tue, 25 Sep 2012 07:11:17 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1885) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TGT2p-0002s6-Pa for qemu-devel@nongnu.org; Tue, 25 Sep 2012 07:11:16 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q8PBB3wh003526 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 25 Sep 2012 07:11:03 -0400 Received: from redhat.com (vpn1-4-15.ams2.redhat.com [10.36.4.15]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id q8PBB0f6001432; Tue, 25 Sep 2012 07:11:01 -0400 Date: Tue, 25 Sep 2012 13:12:35 +0200 From: "Michael S. Tsirkin" To: qemu-devel@nongnu.org, Jason Wang , Anthony Liguori , stefanha@linux.vnet.ibm.com, aurelien@aurel32.net Message-ID: <636a33d7789a53e401b58136f5257f1432e0ac4b.1348571185.git.mst@redhat.com> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCHv2 08/14] virtio-net: switch tx to safe iov functions X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Avoid mangling iovec manually: use safe iov_* functions. Signed-off-by: Michael S. Tsirkin --- hw/virtio-net.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-) diff --git a/hw/virtio-net.c b/hw/virtio-net.c index b9a8be4..358093e 100644 --- a/hw/virtio-net.c +++ b/hw/virtio-net.c @@ -715,10 +715,10 @@ static int32_t virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq) } while (virtqueue_pop(vq, &elem)) { - ssize_t ret, len = 0; + ssize_t ret, len; unsigned int out_num = elem.out_num; struct iovec *out_sg = &elem.out_sg[0]; - unsigned hdr_len; + struct iovec sg[VIRTQUEUE_MAX_SIZE]; /* hdr_len refers to the header received from the guest */ hdr_len = n->mergeable_rx_bufs ? @@ -730,18 +730,25 @@ static int32_t virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq) exit(1); } - /* ignore the header if GSO is not supported */ - if (!n->has_vnet_hdr) { - out_num--; - out_sg++; - len += hdr_len; - } else if (n->mergeable_rx_bufs) { - /* tapfd expects a struct virtio_net_hdr */ - hdr_len -= sizeof(struct virtio_net_hdr); - out_sg->iov_len -= hdr_len; - len += hdr_len; + /* + * If host wants to see the guest header as is, we can + * pass it on unchanged. Otherwise, copy just the parts + * that host is interested in. + */ + assert(n->host_hdr_len <= n->guest_hdr_len); + if (n->host_hdr_len != n->guest_hdr_len) { + unsigned sg_num = iov_copy(sg, ARRAY_SIZE(sg), + out_sg, out_num, + 0, n->host_hdr_len); + sg_num += iov_copy(sg + sg_num, ARRAY_SIZE(sg) - sg_num, + out_sg, out_num, + n->guest_hdr_len, -1); + out_num = sg_num; + out_sg = sg; } + len = hdr_len; + ret = qemu_sendv_packet_async(&n->nic->nc, out_sg, out_num, virtio_net_tx_complete); if (ret == 0) {