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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0794CC54EBE for ; Fri, 13 Jan 2023 03:00:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232583AbjAMDAK (ORCPT ); Thu, 12 Jan 2023 22:00:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34244 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231911AbjAMDAJ (ORCPT ); Thu, 12 Jan 2023 22:00:09 -0500 Received: from out30-130.freemail.mail.aliyun.com (out30-130.freemail.mail.aliyun.com [115.124.30.130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DD06C5E67A; Thu, 12 Jan 2023 19:00:02 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R201e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045168;MF=hengqi@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0VZSlGyA_1673578791; Received: from 30.221.147.157(mailfrom:hengqi@linux.alibaba.com fp:SMTPD_---0VZSlGyA_1673578791) by smtp.aliyun-inc.com; Fri, 13 Jan 2023 10:59:52 +0800 Message-ID: Date: Fri, 13 Jan 2023 10:59:51 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:108.0) Gecko/20100101 Thunderbird/108.0 Subject: Re: [PATCH v3 2/9] virtio-net: set up xdp for multi buffer packets To: Jason Wang , netdev@vger.kernel.org, bpf@vger.kernel.org Cc: "Michael S . Tsirkin" , Paolo Abeni , Jakub Kicinski , John Fastabend , "David S . Miller" , Daniel Borkmann , Alexei Starovoitov , Eric Dumazet , Xuan Zhuo References: <20230103064012.108029-1-hengqi@linux.alibaba.com> <20230103064012.108029-3-hengqi@linux.alibaba.com> From: Heng Qi In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org 在 2023/1/13 上午10:49, Jason Wang 写道: > > 在 2023/1/3 14:40, Heng Qi 写道: >> When the xdp program sets xdp.frags, which means it can process >> multi-buffer packets over larger MTU, so we continue to support xdp. >> But for single-buffer xdp, we should keep checking for MTU. >> >> Signed-off-by: Heng Qi >> Reviewed-by: Xuan Zhuo >> --- >>   drivers/net/virtio_net.c | 10 ++++++---- >>   1 file changed, 6 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >> index 443aa7b8f0ad..60e199811212 100644 >> --- a/drivers/net/virtio_net.c >> +++ b/drivers/net/virtio_net.c >> @@ -3074,7 +3074,9 @@ static int >> virtnet_restore_guest_offloads(struct virtnet_info *vi) >>   static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog >> *prog, >>                  struct netlink_ext_ack *extack) >>   { >> -    unsigned long int max_sz = PAGE_SIZE - sizeof(struct >> padded_vnet_hdr); >> +    unsigned int room = SKB_DATA_ALIGN(VIRTIO_XDP_HEADROOM + >> +                       sizeof(struct skb_shared_info)); >> +    unsigned int max_sz = PAGE_SIZE - room - ETH_HLEN; >>       struct virtnet_info *vi = netdev_priv(dev); >>       struct bpf_prog *old_prog; >>       u16 xdp_qp = 0, curr_qp; >> @@ -3095,9 +3097,9 @@ static int virtnet_xdp_set(struct net_device >> *dev, struct bpf_prog *prog, >>           return -EINVAL; >>       } >>   -    if (dev->mtu > max_sz) { >> -        NL_SET_ERR_MSG_MOD(extack, "MTU too large to enable XDP"); >> -        netdev_warn(dev, "XDP requires MTU less than %lu\n", max_sz); >> +    if (prog && !prog->aux->xdp_has_frags && dev->mtu > max_sz) { >> +        NL_SET_ERR_MSG_MOD(extack, "MTU too large to enable XDP >> without frags"); >> +        netdev_warn(dev, "single-buffer XDP requires MTU less than >> %u\n", max_sz); >>           return -EINVAL; >>       } > > > I think we probably need to backport this to -stable. So I suggest to > move/squash the check of !prog->aux->xdp_has_frags to one of the > following patch. Sure, and you are right. Thanks. > > With this, > > Acked-by: Jason Wang > > Thanks > >