From patchwork Sat Jan 16 02:59:26 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xuan Zhuo X-Patchwork-Id: 12024565 X-Patchwork-Delegate: kuba@kernel.org 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=unavailable 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 1A78CC43331 for ; Sat, 16 Jan 2021 03:00:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F0394238D6 for ; Sat, 16 Jan 2021 03:00:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729337AbhAPDAV (ORCPT ); Fri, 15 Jan 2021 22:00:21 -0500 Received: from out30-131.freemail.mail.aliyun.com ([115.124.30.131]:33937 "EHLO out30-131.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728493AbhAPDAU (ORCPT ); Fri, 15 Jan 2021 22:00:20 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R311e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=alimailimapcm10staff010182156082;MF=xuanzhuo@linux.alibaba.com;NM=1;PH=DS;RN=19;SR=0;TI=SMTPD_---0ULrQCa5_1610765970; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0ULrQCa5_1610765970) by smtp.aliyun-inc.com(127.0.0.1); Sat, 16 Jan 2021 10:59:30 +0800 From: Xuan Zhuo To: netdev@vger.kernel.org Cc: "Michael S. Tsirkin" , Jason Wang , "David S. Miller" , Jakub Kicinski , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Magnus Karlsson , Jonathan Lemon , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , KP Singh , virtualization@lists.linux-foundation.org, bpf@vger.kernel.org Subject: [PATCH net-next v2 5/7] virtio-net, xsk: realize the function of xsk packet sending Date: Sat, 16 Jan 2021 10:59:26 +0800 Message-Id: <9e1f5a4b633887ce1f66e39bc762b8497a379a43.1610765285.git.xuanzhuo@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: References: In-Reply-To: References: Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org virtnet_xsk_run will be called in the tx interrupt handling function virtnet_poll_tx. The sending process gets desc from the xsk tx queue, and assembles it to send the data. Compared with other drivers, a special place is that the page of the data in xsk is used here instead of the dma address. Because the virtio interface does not use the dma address. Signed-off-by: Xuan Zhuo --- drivers/net/virtio_net.c | 200 ++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 197 insertions(+), 3 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index a62d456..42aa9ad 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -119,6 +119,8 @@ struct virtnet_xsk_hdr { u32 len; }; +#define VIRTNET_STATE_XSK_WAKEUP 1 + #define VIRTNET_SQ_STAT(m) offsetof(struct virtnet_sq_stats, m) #define VIRTNET_RQ_STAT(m) offsetof(struct virtnet_rq_stats, m) @@ -163,9 +165,12 @@ struct send_queue { struct xsk_buff_pool __rcu *pool; struct virtnet_xsk_hdr __rcu *hdr; + unsigned long state; u64 hdr_con; u64 hdr_pro; u64 hdr_n; + struct xdp_desc last_desc; + bool wait_slot; } xsk; }; @@ -284,6 +289,8 @@ static void __free_old_xmit_ptr(struct send_queue *sq, bool in_napi, bool xsk_wakeup, unsigned int *_packets, unsigned int *_bytes); static void free_old_xmit_skbs(struct send_queue *sq, bool in_napi); +static int virtnet_xsk_run(struct send_queue *sq, + struct xsk_buff_pool *pool, int budget); static bool is_xdp_frame(void *ptr) { @@ -1590,6 +1597,8 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget) struct virtnet_info *vi = sq->vq->vdev->priv; unsigned int index = vq2txq(sq->vq); struct netdev_queue *txq; + struct xsk_buff_pool *pool; + int work = 0; if (unlikely(is_xdp_raw_buffer_queue(vi, index))) { /* We don't need to enable cb for XDP */ @@ -1599,15 +1608,26 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget) txq = netdev_get_tx_queue(vi->dev, index); __netif_tx_lock(txq, raw_smp_processor_id()); - free_old_xmit_skbs(sq, true); + + rcu_read_lock(); + pool = rcu_dereference(sq->xsk.pool); + if (pool) { + work = virtnet_xsk_run(sq, pool, budget); + rcu_read_unlock(); + } else { + rcu_read_unlock(); + free_old_xmit_skbs(sq, true); + } + __netif_tx_unlock(txq); - virtqueue_napi_complete(napi, sq->vq, 0); + if (work < budget) + virtqueue_napi_complete(napi, sq->vq, 0); if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) netif_tx_wake_queue(txq); - return 0; + return work; } static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) @@ -2647,6 +2667,180 @@ static int virtnet_xdp(struct net_device *dev, struct netdev_bpf *xdp) } } +static int virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool, + struct xdp_desc *desc) +{ + struct virtnet_info *vi = sq->vq->vdev->priv; + void *data, *ptr; + struct page *page; + struct virtnet_xsk_hdr *xskhdr; + u32 idx, offset, n, i, copy, copied; + u64 addr; + int err, m; + + addr = desc->addr; + + data = xsk_buff_raw_get_data(pool, addr); + offset = offset_in_page(data); + + /* one for hdr, one for the first page */ + n = 2; + m = desc->len - (PAGE_SIZE - offset); + if (m > 0) { + n += m >> PAGE_SHIFT; + if (m & PAGE_MASK) + ++n; + + n = min_t(u32, n, ARRAY_SIZE(sq->sg)); + } + + idx = sq->xsk.hdr_con % sq->xsk.hdr_n; + xskhdr = &sq->xsk.hdr[idx]; + + /* xskhdr->hdr has been memset to zero, so not need to clear again */ + + sg_init_table(sq->sg, n); + sg_set_buf(sq->sg, &xskhdr->hdr, vi->hdr_len); + + copied = 0; + for (i = 1; i < n; ++i) { + copy = min_t(int, desc->len - copied, PAGE_SIZE - offset); + + page = xsk_buff_raw_get_page(pool, addr + copied); + + sg_set_page(sq->sg + i, page, copy, offset); + copied += copy; + if (offset) + offset = 0; + } + + xskhdr->len = desc->len; + ptr = xdp_to_ptr(&xskhdr->type); + + err = virtqueue_add_outbuf(sq->vq, sq->sg, n, ptr, GFP_ATOMIC); + if (unlikely(err)) + sq->xsk.last_desc = *desc; + else + sq->xsk.hdr_con++; + + return err; +} + +static bool virtnet_xsk_dev_is_full(struct send_queue *sq) +{ + if (sq->vq->num_free < 2 + MAX_SKB_FRAGS) + return true; + + if (sq->xsk.hdr_con == sq->xsk.hdr_pro) + return true; + + return false; +} + +static int virtnet_xsk_xmit_zc(struct send_queue *sq, + struct xsk_buff_pool *pool, unsigned int budget) +{ + struct xdp_desc desc; + int err, packet = 0; + int ret = -EAGAIN; + + if (sq->xsk.last_desc.addr) { + err = virtnet_xsk_xmit(sq, pool, &sq->xsk.last_desc); + if (unlikely(err)) + return -EBUSY; + + ++packet; + sq->xsk.last_desc.addr = 0; + } + + while (budget-- > 0) { + if (virtnet_xsk_dev_is_full(sq)) { + ret = -EBUSY; + break; + } + + if (!xsk_tx_peek_desc(pool, &desc)) { + /* done */ + ret = 0; + break; + } + + err = virtnet_xsk_xmit(sq, pool, &desc); + if (unlikely(err)) { + ret = -EBUSY; + break; + } + + ++packet; + } + + if (packet) { + xsk_tx_release(pool); + + if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) { + u64_stats_update_begin(&sq->stats.syncp); + sq->stats.kicks++; + u64_stats_update_end(&sq->stats.syncp); + } + } + + return ret; +} + +static int virtnet_xsk_run(struct send_queue *sq, + struct xsk_buff_pool *pool, int budget) +{ + int err, ret = 0; + unsigned int _packets = 0; + unsigned int _bytes = 0; + + sq->xsk.wait_slot = false; + + __free_old_xmit_ptr(sq, true, false, &_packets, &_bytes); + + err = virtnet_xsk_xmit_zc(sq, pool, xsk_budget); + if (!err) { + struct xdp_desc desc; + + clear_bit(VIRTNET_STATE_XSK_WAKEUP, &sq->xsk.state); + xsk_set_tx_need_wakeup(pool); + + /* Race breaker. If new is coming after last xmit + * but before flag change + */ + + if (!xsk_tx_peek_desc(pool, &desc)) + goto end; + + set_bit(VIRTNET_STATE_XSK_WAKEUP, &sq->xsk.state); + xsk_clear_tx_need_wakeup(pool); + + sq->xsk.last_desc = desc; + ret = budget; + goto end; + } + + xsk_clear_tx_need_wakeup(pool); + + if (err == -EAGAIN) { + ret = budget; + goto end; + } + + __free_old_xmit_ptr(sq, true, false, &_packets, &_bytes); + + if (!virtnet_xsk_dev_is_full(sq)) { + ret = budget; + goto end; + } + + sq->xsk.wait_slot = true; + + virtnet_sq_stop_check(sq, true); +end: + return ret; +} + static int virtnet_get_phys_port_name(struct net_device *dev, char *buf, size_t len) {