From patchwork Mon Feb 24 13:25:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Ivanov X-Patchwork-Id: 1243081 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=cambridgegreys.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48R2rf4hNLz9sPk for ; Tue, 25 Feb 2020 00:26:10 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727158AbgBXN0J (ORCPT ); Mon, 24 Feb 2020 08:26:09 -0500 Received: from ivanoab7.miniserver.com ([37.128.132.42]:48604 "EHLO www.kot-begemot.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726762AbgBXN0I (ORCPT ); Mon, 24 Feb 2020 08:26:08 -0500 Received: from tun252.jain.kot-begemot.co.uk ([192.168.18.6] helo=jain.kot-begemot.co.uk) by www.kot-begemot.co.uk with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1j6DkI-0005jE-6t; Mon, 24 Feb 2020 13:26:06 +0000 Received: from jain.kot-begemot.co.uk ([192.168.3.3]) by jain.kot-begemot.co.uk with esmtp (Exim 4.92) (envelope-from ) id 1j6Dk9-0000Yj-0t; Mon, 24 Feb 2020 13:25:57 +0000 From: anton.ivanov@cambridgegreys.com To: netdev@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-um@lists.infradead.org Cc: mst@redhat.com, jasowang@redhat.com, eric.dumazet@gmail.com, Anton Ivanov Subject: [PATCH v3] virtio: Work around frames incorrectly marked as gso Date: Mon, 24 Feb 2020 13:25:50 +0000 Message-Id: <20200224132550.2083-1-anton.ivanov@cambridgegreys.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-Spam-Score: -1.0 X-Spam-Score: -1.0 X-Clacks-Overhead: GNU Terry Pratchett Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Anton Ivanov Some of the locally generated frames marked as GSO which arrive at virtio_net_hdr_from_skb() have no GSO_TYPE, no fragments (data_len = 0) and length significantly shorter than the MTU (752 in my experiments). This is observed on raw sockets reading off vEth interfaces in all 4.x and 5.x kernels. The frames are reported as invalid, while they are in fact gso-less frames. The easiest way to reproduce is to connect a User Mode Linux instance to the host using the vector raw transport and a vEth interface. Vector raw uses recvmmsg/sendmmsg with virtio headers on af_packet sockets. When running iperf between the UML and the host, UML regularly complains about EINVAL return from recvmmsg. This patch marks the vnet header as non-GSO instead of reporting it as invalid. Signed-off-by: Anton Ivanov Reviewed-by: Michael S. Tsirkin --- include/linux/virtio_net.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index 0d1fe9297ac6..2c99c752cb20 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -98,10 +98,11 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, bool has_data_valid, int vlan_hlen) { + struct skb_shared_info *sinfo = skb_shinfo(skb); + memset(hdr, 0, sizeof(*hdr)); /* no info leak */ - if (skb_is_gso(skb)) { - struct skb_shared_info *sinfo = skb_shinfo(skb); + if (skb_is_gso(skb) && sinfo->gso_type) { /* This is a hint as to how much should be linear. */ hdr->hdr_len = __cpu_to_virtio16(little_endian,