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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 65E2AC0650E for ; Mon, 1 Jul 2019 09:30:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CC08F206E0 for ; Mon, 1 Jul 2019 09:30:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728470AbfGAJap (ORCPT ); Mon, 1 Jul 2019 05:30:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37690 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728143AbfGAJao (ORCPT ); Mon, 1 Jul 2019 05:30:44 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3D1A33082A49; Mon, 1 Jul 2019 09:30:39 +0000 (UTC) Received: from [10.72.12.166] (ovpn-12-166.pek2.redhat.com [10.72.12.166]) by smtp.corp.redhat.com (Postfix) with ESMTP id 344E019732; Mon, 1 Jul 2019 09:30:30 +0000 (UTC) Subject: Re: [PATCH bpf-next] virtio_net: add XDP meta data support To: Yuya Kusakabe , davem@davemloft.net Cc: "Michael S. Tsirkin" , Alexei Starovoitov , Daniel Borkmann , Jakub Kicinski , Jesper Dangaard Brouer , John Fastabend , Martin KaFai Lau , Song Liu , Yonghong Song , netdev@vger.kernel.org References: <20190627080641.3266-1-yuya.kusakabe@gmail.com> From: Jason Wang Message-ID: Date: Mon, 1 Jul 2019 17:30:29 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.1 MIME-Version: 1.0 In-Reply-To: <20190627080641.3266-1-yuya.kusakabe@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Mon, 01 Jul 2019 09:30:44 +0000 (UTC) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2019/6/27 下午4:06, Yuya Kusakabe wrote: > This adds XDP meta data support to both receive_small() and > receive_mergeable(). > > Fixes: de8f3a83b0a0 ("bpf: add meta pointer for direct access") > Signed-off-by: Yuya Kusakabe > --- > drivers/net/virtio_net.c | 40 +++++++++++++++++++++++++++++----------- > 1 file changed, 29 insertions(+), 11 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 4f3de0ac8b0b..e787657fc568 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -371,7 +371,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, > struct receive_queue *rq, > struct page *page, unsigned int offset, > unsigned int len, unsigned int truesize, > - bool hdr_valid) > + bool hdr_valid, unsigned int metasize) > { > struct sk_buff *skb; > struct virtio_net_hdr_mrg_rxbuf *hdr; > @@ -393,17 +393,25 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, > else > hdr_padded_len = sizeof(struct padded_vnet_hdr); > > - if (hdr_valid) > + if (hdr_valid && !metasize) > memcpy(hdr, p, hdr_len); > > len -= hdr_len; > offset += hdr_padded_len; > p += hdr_padded_len; > > - copy = len; > + copy = len + metasize; > if (copy > skb_tailroom(skb)) > copy = skb_tailroom(skb); > - skb_put_data(skb, p, copy); > + > + if (metasize) { > + skb_put_data(skb, p - metasize, copy); I would rather keep copy untouched above, and use copy + metasize here, then you can save the following decrement  as well. Or tweak the caller the count the meta in to offset, then we need only deal with skb_pull() and skb_metadata_set() here. > + __skb_pull(skb, metasize); > + skb_metadata_set(skb, metasize); > + copy -= metasize; > + } else { > + skb_put_data(skb, p, copy); > + } > > len -= copy; > offset += copy; > @@ -644,6 +652,7 @@ static struct sk_buff *receive_small(struct net_device *dev, > unsigned int delta = 0; > struct page *xdp_page; > int err; > + unsigned int metasize = 0; > > len -= vi->hdr_len; > stats->bytes += len; > @@ -683,8 +692,8 @@ static struct sk_buff *receive_small(struct net_device *dev, > > xdp.data_hard_start = buf + VIRTNET_RX_PAD + vi->hdr_len; > xdp.data = xdp.data_hard_start + xdp_headroom; > - xdp_set_data_meta_invalid(&xdp); > xdp.data_end = xdp.data + len; > + xdp.data_meta = xdp.data; > xdp.rxq = &rq->xdp_rxq; > orig_data = xdp.data; > act = bpf_prog_run_xdp(xdp_prog, &xdp); > @@ -695,9 +704,11 @@ static struct sk_buff *receive_small(struct net_device *dev, > /* Recalculate length in case bpf program changed it */ > delta = orig_data - xdp.data; > len = xdp.data_end - xdp.data; > + metasize = xdp.data - xdp.data_meta; > break; > case XDP_TX: > stats->xdp_tx++; > + xdp.data_meta = xdp.data; Why need this? > xdpf = convert_to_xdp_frame(&xdp); > if (unlikely(!xdpf)) > goto err_xdp; > @@ -735,11 +746,14 @@ static struct sk_buff *receive_small(struct net_device *dev, > } > skb_reserve(skb, headroom - delta); > skb_put(skb, len); > - if (!delta) { > + if (!delta && !metasize) { > buf += header_offset; > memcpy(skb_vnet_hdr(skb), buf, vi->hdr_len); > } /* keep zeroed vnet hdr since packet was changed by bpf */ Is there any method to preserve the vnet header here? We probably don't want to lose it for XDP_PASS when packet is not modified. > > + if (metasize) > + skb_metadata_set(skb, metasize); > + > err: > return skb; > > @@ -761,7 +775,7 @@ static struct sk_buff *receive_big(struct net_device *dev, > { > struct page *page = buf; > struct sk_buff *skb = page_to_skb(vi, rq, page, 0, len, > - PAGE_SIZE, true); > + PAGE_SIZE, true, 0); > > stats->bytes += len - vi->hdr_len; > if (unlikely(!skb)) > @@ -793,6 +807,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > unsigned int truesize; > unsigned int headroom = mergeable_ctx_to_headroom(ctx); > int err; > + unsigned int metasize = 0; > > head_skb = NULL; > stats->bytes += len - vi->hdr_len; > @@ -839,8 +854,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > data = page_address(xdp_page) + offset; > xdp.data_hard_start = data - VIRTIO_XDP_HEADROOM + vi->hdr_len; > xdp.data = data + vi->hdr_len; > - xdp_set_data_meta_invalid(&xdp); > xdp.data_end = xdp.data + (len - vi->hdr_len); > + xdp.data_meta = xdp.data; > xdp.rxq = &rq->xdp_rxq; > > act = bpf_prog_run_xdp(xdp_prog, &xdp); > @@ -859,18 +874,20 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > * adjusted > */ > len = xdp.data_end - xdp.data + vi->hdr_len; > + metasize = xdp.data - xdp.data_meta; > /* We can only create skb based on xdp_page. */ > if (unlikely(xdp_page != page)) { > rcu_read_unlock(); > put_page(page); > head_skb = page_to_skb(vi, rq, xdp_page, > - offset, len, > - PAGE_SIZE, false); > + offset, len, > + PAGE_SIZE, false, metasize); Indentation is wired. Thanks > return head_skb; > } > break; > case XDP_TX: > stats->xdp_tx++; > + xdp.data_meta = xdp.data; > xdpf = convert_to_xdp_frame(&xdp); > if (unlikely(!xdpf)) > goto err_xdp; > @@ -921,7 +938,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > goto err_skb; > } > > - head_skb = page_to_skb(vi, rq, page, offset, len, truesize, !xdp_prog); > + head_skb = page_to_skb(vi, rq, page, offset, len, truesize, !xdp_prog, > + metasize); > curr_skb = head_skb; > > if (unlikely(!curr_skb))