From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-97.freemail.mail.aliyun.com (out30-97.freemail.mail.aliyun.com [115.124.30.97]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CC53933CC2; Wed, 17 Apr 2024 07:59:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.97 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713340797; cv=none; b=djBEbelzy9+QsuUheIGeQ1Gm83Ym2aa7/SFTSwKptSLmgfVWg9VI+YuRzhu3DzY8Vkxjj1An+vel5T04zhvuuLRfqLdh8+e3W5QQsAOa4RvYOfse3O/XNsmySq6x/br97pMU4s48uycPuzceZy9zIfKMF7AybsljElNIOEmqBw0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713340797; c=relaxed/simple; bh=36MTnlcp33XwHHxLO/m8OsWJKQx4HmShuAbNDoPWRD0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=R6Bz8Bb39dxonzJPH481vGIUvTl83S9Lkj5WjXiqhTBus1C7d4TlIGppjoYJ4QMOqPAmWpDPjhE9qKitR345J/RED3JESHFPfN/khSVraINJiFEEhCVSVjr84b5034UZGIJRISs+Vj31oIxtz5aaHFJ2iRYjZzSMBiebhVufukY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=SOWomeNd; arc=none smtp.client-ip=115.124.30.97 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="SOWomeNd" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1713340787; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=00eV10aYqBSEYTxuhgv4GNMQMHte1deFn+CrhZCt04s=; b=SOWomeNdq6rv0zkORBWlsPAY7d+p2MNfkmyFhpn5epQiCVr+Oe7NJBvOgU82+BdpRpNl6cMqv+jvGfhsqCoBhq3GUNHnJRL1M1kPVetAROOywJMnp1x0wjtUJHOnVvt6S0/gjA4U4JEYyBP966ycP2IluPTbPsr2OlTrAEqV4Wg= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R681e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045192;MF=hengqi@linux.alibaba.com;NM=1;PH=DS;RN=16;SR=0;TI=SMTPD_---0W4kiWz7_1713340784; Received: from 30.221.148.177(mailfrom:hengqi@linux.alibaba.com fp:SMTPD_---0W4kiWz7_1713340784) by smtp.aliyun-inc.com; Wed, 17 Apr 2024 15:59:46 +0800 Message-ID: Date: Wed, 17 Apr 2024 15:59:44 +0800 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next v9] virtio_net: Support RX hash XDP hint To: Liang Chen Cc: netdev@vger.kernel.org, virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, ast@kernel.org, "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jesper Dangaard Brouer , John Fastabend References: <20240417071822.27831-1-liangchen.linux@gmail.com> From: Heng Qi In-Reply-To: <20240417071822.27831-1-liangchen.linux@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 在 2024/4/17 下午3:18, Liang Chen 写道: > The RSS hash report is a feature that's part of the virtio specification. > Currently, virtio backends like qemu, vdpa (mlx5), and potentially vhost > (still a work in progress as per [1]) support this feature. While the > capability to obtain the RSS hash has been enabled in the normal path, > it's currently missing in the XDP path. Therefore, we are introducing > XDP hints through kfuncs to allow XDP programs to access the RSS hash. > > 1. > https://lore.kernel.org/all/20231015141644.260646-1-akihiko.odaki@daynix.com/#r > > Signed-off-by: Liang Chen Reviewed-by: Heng Qi Thanks. > --- > Changes from v8: > - move max table macro out of uAPI > Changes from v7: > - use table lookup for rss hash type > Changes from v6: > - fix a coding style issue > Changes from v5: > - Preservation of the hash value has been dropped, following the conclusion > from discussions in V3 reviews. The virtio_net driver doesn't > accessing/using the virtio_net_hdr after the XDP program execution, so > nothing tragic should happen. As to the xdp program, if it smashes the > entry in virtio header, it is likely buggy anyways. Additionally, looking > up the Intel IGC driver, it also does not bother with this particular > aspect. > --- > drivers/net/virtio_net.c | 43 ++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 43 insertions(+) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index c22d1118a133..eb99bf6c555e 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -4621,6 +4621,48 @@ static void virtnet_set_big_packets(struct virtnet_info *vi, const int mtu) > } > } > > +#define VIRTIO_NET_HASH_REPORT_MAX_TABLE 10 > +static enum xdp_rss_hash_type > +virtnet_xdp_rss_type[VIRTIO_NET_HASH_REPORT_MAX_TABLE] = { > + [VIRTIO_NET_HASH_REPORT_NONE] = XDP_RSS_TYPE_NONE, > + [VIRTIO_NET_HASH_REPORT_IPv4] = XDP_RSS_TYPE_L3_IPV4, > + [VIRTIO_NET_HASH_REPORT_TCPv4] = XDP_RSS_TYPE_L4_IPV4_TCP, > + [VIRTIO_NET_HASH_REPORT_UDPv4] = XDP_RSS_TYPE_L4_IPV4_UDP, > + [VIRTIO_NET_HASH_REPORT_IPv6] = XDP_RSS_TYPE_L3_IPV6, > + [VIRTIO_NET_HASH_REPORT_TCPv6] = XDP_RSS_TYPE_L4_IPV6_TCP, > + [VIRTIO_NET_HASH_REPORT_UDPv6] = XDP_RSS_TYPE_L4_IPV6_UDP, > + [VIRTIO_NET_HASH_REPORT_IPv6_EX] = XDP_RSS_TYPE_L3_IPV6_EX, > + [VIRTIO_NET_HASH_REPORT_TCPv6_EX] = XDP_RSS_TYPE_L4_IPV6_TCP_EX, > + [VIRTIO_NET_HASH_REPORT_UDPv6_EX] = XDP_RSS_TYPE_L4_IPV6_UDP_EX > +}; > + > +static int virtnet_xdp_rx_hash(const struct xdp_md *_ctx, u32 *hash, > + enum xdp_rss_hash_type *rss_type) > +{ > + const struct xdp_buff *xdp = (void *)_ctx; > + struct virtio_net_hdr_v1_hash *hdr_hash; > + struct virtnet_info *vi; > + u16 hash_report; > + > + if (!(xdp->rxq->dev->features & NETIF_F_RXHASH)) > + return -ENODATA; > + > + vi = netdev_priv(xdp->rxq->dev); > + hdr_hash = (struct virtio_net_hdr_v1_hash *)(xdp->data - vi->hdr_len); > + hash_report = __le16_to_cpu(hdr_hash->hash_report); > + > + if (hash_report >= VIRTIO_NET_HASH_REPORT_MAX_TABLE) > + hash_report = VIRTIO_NET_HASH_REPORT_NONE; > + > + *rss_type = virtnet_xdp_rss_type[hash_report]; > + *hash = __le32_to_cpu(hdr_hash->hash_value); > + return 0; > +} > + > +static const struct xdp_metadata_ops virtnet_xdp_metadata_ops = { > + .xmo_rx_hash = virtnet_xdp_rx_hash, > +}; > + > static int virtnet_probe(struct virtio_device *vdev) > { > int i, err = -ENOMEM; > @@ -4747,6 +4789,7 @@ static int virtnet_probe(struct virtio_device *vdev) > VIRTIO_NET_RSS_HASH_TYPE_UDP_EX); > > dev->hw_features |= NETIF_F_RXHASH; > + dev->xdp_metadata_ops = &virtnet_xdp_metadata_ops; > } > > if (vi->has_rss_hash_report)