xen networking: add basic XDP support for xen-netfront
The patch adds a basic XDP processing to xen-netfront driver. We ran an XDP program for an RX response received from netback driver. Also we request xen-netback to adjust data offset for bpf_xdp_adjust_head() header space for custom headers. synchronization between frontend and backend parts is done by using xenbus state switching: Reconfiguring -> Reconfigured- > Connected UDP packets drop rate using xdp program is around 310 kpps using ./pktgen_sample04_many_flows.sh and 160 kpps without the patch. Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Denis Kirjanov
David S. Miller
Родитель
2cef30d7bd
Коммит
6c5aa6fc4d
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@ -495,6 +495,7 @@ config XEN_NETDEV_FRONTEND
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tristate "Xen network device frontend driver"
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depends on XEN
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select XEN_XENBUS_FRONTEND
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select PAGE_POOL
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default y
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help
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This driver provides support for Xen paravirtual network
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@ -44,6 +44,9 @@
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <net/ip.h>
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#include <linux/bpf.h>
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#include <net/page_pool.h>
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#include <linux/bpf_trace.h>
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#include <xen/xen.h>
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#include <xen/xenbus.h>
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@ -102,6 +105,8 @@ struct netfront_queue {
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char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
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struct netfront_info *info;
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struct bpf_prog __rcu *xdp_prog;
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struct napi_struct napi;
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/* Split event channels support, tx_* == rx_* when using
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@ -144,6 +149,9 @@ struct netfront_queue {
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struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
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grant_ref_t gref_rx_head;
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grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
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struct page_pool *page_pool;
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struct xdp_rxq_info xdp_rxq;
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};
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struct netfront_info {
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@ -159,6 +167,10 @@ struct netfront_info {
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struct netfront_stats __percpu *rx_stats;
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struct netfront_stats __percpu *tx_stats;
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/* XDP state */
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bool netback_has_xdp_headroom;
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bool netfront_xdp_enabled;
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atomic_t rx_gso_checksum_fixup;
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};
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@ -265,8 +277,8 @@ static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue)
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if (unlikely(!skb))
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return NULL;
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page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
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if (!page) {
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page = page_pool_dev_alloc_pages(queue->page_pool);
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if (unlikely(!page)) {
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kfree_skb(skb);
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return NULL;
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}
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@ -560,6 +572,66 @@ static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb,
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return queue_idx;
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}
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static int xennet_xdp_xmit_one(struct net_device *dev,
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struct netfront_queue *queue,
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struct xdp_frame *xdpf)
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{
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struct netfront_info *np = netdev_priv(dev);
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struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
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int notify;
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xennet_make_first_txreq(queue, NULL,
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virt_to_page(xdpf->data),
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offset_in_page(xdpf->data),
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xdpf->len);
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RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
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if (notify)
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notify_remote_via_irq(queue->tx_irq);
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u64_stats_update_begin(&tx_stats->syncp);
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tx_stats->bytes += xdpf->len;
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tx_stats->packets++;
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u64_stats_update_end(&tx_stats->syncp);
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xennet_tx_buf_gc(queue);
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return 0;
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}
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static int xennet_xdp_xmit(struct net_device *dev, int n,
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struct xdp_frame **frames, u32 flags)
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{
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unsigned int num_queues = dev->real_num_tx_queues;
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struct netfront_info *np = netdev_priv(dev);
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struct netfront_queue *queue = NULL;
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unsigned long irq_flags;
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int drops = 0;
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int i, err;
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if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
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return -EINVAL;
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queue = &np->queues[smp_processor_id() % num_queues];
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spin_lock_irqsave(&queue->tx_lock, irq_flags);
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for (i = 0; i < n; i++) {
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struct xdp_frame *xdpf = frames[i];
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if (!xdpf)
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continue;
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err = xennet_xdp_xmit_one(dev, queue, xdpf);
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if (err) {
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xdp_return_frame_rx_napi(xdpf);
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drops++;
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}
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}
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spin_unlock_irqrestore(&queue->tx_lock, irq_flags);
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return n - drops;
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}
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#define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1)
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static netdev_tx_t xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
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@ -778,23 +850,82 @@ static int xennet_get_extras(struct netfront_queue *queue,
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return err;
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}
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static u32 xennet_run_xdp(struct netfront_queue *queue, struct page *pdata,
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struct xen_netif_rx_response *rx, struct bpf_prog *prog,
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struct xdp_buff *xdp, bool *need_xdp_flush)
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{
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struct xdp_frame *xdpf;
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u32 len = rx->status;
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u32 act = XDP_PASS;
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int err;
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xdp->data_hard_start = page_address(pdata);
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xdp->data = xdp->data_hard_start + XDP_PACKET_HEADROOM;
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xdp_set_data_meta_invalid(xdp);
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xdp->data_end = xdp->data + len;
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xdp->rxq = &queue->xdp_rxq;
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xdp->frame_sz = XEN_PAGE_SIZE - XDP_PACKET_HEADROOM;
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act = bpf_prog_run_xdp(prog, xdp);
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switch (act) {
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case XDP_TX:
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get_page(pdata);
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xdpf = xdp_convert_buff_to_frame(xdp);
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err = xennet_xdp_xmit(queue->info->netdev, 1, &xdpf, 0);
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if (unlikely(err < 0))
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trace_xdp_exception(queue->info->netdev, prog, act);
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break;
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case XDP_REDIRECT:
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get_page(pdata);
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err = xdp_do_redirect(queue->info->netdev, xdp, prog);
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*need_xdp_flush = true;
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if (unlikely(err))
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trace_xdp_exception(queue->info->netdev, prog, act);
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break;
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case XDP_PASS:
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case XDP_DROP:
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break;
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case XDP_ABORTED:
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trace_xdp_exception(queue->info->netdev, prog, act);
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break;
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default:
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bpf_warn_invalid_xdp_action(act);
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}
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return act;
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}
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static int xennet_get_responses(struct netfront_queue *queue,
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struct netfront_rx_info *rinfo, RING_IDX rp,
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struct sk_buff_head *list)
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struct sk_buff_head *list,
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bool *need_xdp_flush)
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{
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struct xen_netif_rx_response *rx = &rinfo->rx;
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struct xen_netif_extra_info *extras = rinfo->extras;
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struct device *dev = &queue->info->netdev->dev;
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int max = XEN_NETIF_NR_SLOTS_MIN + (rx->status <= RX_COPY_THRESHOLD);
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RING_IDX cons = queue->rx.rsp_cons;
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struct sk_buff *skb = xennet_get_rx_skb(queue, cons);
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struct xen_netif_extra_info *extras = rinfo->extras;
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grant_ref_t ref = xennet_get_rx_ref(queue, cons);
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int max = XEN_NETIF_NR_SLOTS_MIN + (rx->status <= RX_COPY_THRESHOLD);
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struct device *dev = &queue->info->netdev->dev;
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struct bpf_prog *xdp_prog;
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struct xdp_buff xdp;
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unsigned long ret;
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int slots = 1;
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int err = 0;
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unsigned long ret;
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u32 verdict;
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if (rx->flags & XEN_NETRXF_extra_info) {
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err = xennet_get_extras(queue, extras, rp);
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if (!err) {
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if (extras[XEN_NETIF_EXTRA_TYPE_XDP - 1].type) {
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struct xen_netif_extra_info *xdp;
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xdp = &extras[XEN_NETIF_EXTRA_TYPE_XDP - 1];
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rx->offset = xdp->u.xdp.headroom;
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}
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}
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cons = queue->rx.rsp_cons;
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}
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@ -827,9 +958,24 @@ static int xennet_get_responses(struct netfront_queue *queue,
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gnttab_release_grant_reference(&queue->gref_rx_head, ref);
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__skb_queue_tail(list, skb);
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rcu_read_lock();
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xdp_prog = rcu_dereference(queue->xdp_prog);
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if (xdp_prog) {
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if (!(rx->flags & XEN_NETRXF_more_data)) {
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/* currently only a single page contains data */
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verdict = xennet_run_xdp(queue,
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skb_frag_page(&skb_shinfo(skb)->frags[0]),
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rx, xdp_prog, &xdp, need_xdp_flush);
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if (verdict != XDP_PASS)
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err = -EINVAL;
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} else {
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/* drop the frame */
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err = -EINVAL;
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}
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}
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rcu_read_unlock();
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next:
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__skb_queue_tail(list, skb);
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if (!(rx->flags & XEN_NETRXF_more_data))
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break;
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@ -998,6 +1144,7 @@ static int xennet_poll(struct napi_struct *napi, int budget)
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struct sk_buff_head errq;
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struct sk_buff_head tmpq;
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int err;
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bool need_xdp_flush = false;
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spin_lock(&queue->rx_lock);
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@ -1014,7 +1161,8 @@ static int xennet_poll(struct napi_struct *napi, int budget)
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memcpy(rx, RING_GET_RESPONSE(&queue->rx, i), sizeof(*rx));
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memset(extras, 0, sizeof(rinfo.extras));
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err = xennet_get_responses(queue, &rinfo, rp, &tmpq);
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err = xennet_get_responses(queue, &rinfo, rp, &tmpq,
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&need_xdp_flush);
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if (unlikely(err)) {
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err:
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@ -1060,6 +1208,8 @@ err:
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i = ++queue->rx.rsp_cons;
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work_done++;
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}
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if (need_xdp_flush)
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xdp_do_flush();
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__skb_queue_purge(&errq);
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@ -1261,6 +1411,101 @@ static void xennet_poll_controller(struct net_device *dev)
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}
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#endif
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#define NETBACK_XDP_HEADROOM_DISABLE 0
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#define NETBACK_XDP_HEADROOM_ENABLE 1
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static int talk_to_netback_xdp(struct netfront_info *np, int xdp)
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{
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int err;
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unsigned short headroom;
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headroom = xdp ? XDP_PACKET_HEADROOM : 0;
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err = xenbus_printf(XBT_NIL, np->xbdev->nodename,
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"xdp-headroom", "%hu",
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headroom);
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if (err)
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pr_warn("Error writing xdp-headroom\n");
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return err;
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}
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static int xennet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
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struct netlink_ext_ack *extack)
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{
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unsigned long max_mtu = XEN_PAGE_SIZE - XDP_PACKET_HEADROOM;
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struct netfront_info *np = netdev_priv(dev);
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struct bpf_prog *old_prog;
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unsigned int i, err;
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if (dev->mtu > max_mtu) {
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netdev_warn(dev, "XDP requires MTU less than %lu\n", max_mtu);
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return -EINVAL;
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}
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if (!np->netback_has_xdp_headroom)
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return 0;
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xenbus_switch_state(np->xbdev, XenbusStateReconfiguring);
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err = talk_to_netback_xdp(np, prog ? NETBACK_XDP_HEADROOM_ENABLE :
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NETBACK_XDP_HEADROOM_DISABLE);
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if (err)
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return err;
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/* avoid the race with XDP headroom adjustment */
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wait_event(module_wq,
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xenbus_read_driver_state(np->xbdev->otherend) ==
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XenbusStateReconfigured);
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np->netfront_xdp_enabled = true;
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old_prog = rtnl_dereference(np->queues[0].xdp_prog);
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if (prog)
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bpf_prog_add(prog, dev->real_num_tx_queues);
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for (i = 0; i < dev->real_num_tx_queues; ++i)
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rcu_assign_pointer(np->queues[i].xdp_prog, prog);
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if (old_prog)
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for (i = 0; i < dev->real_num_tx_queues; ++i)
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bpf_prog_put(old_prog);
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xenbus_switch_state(np->xbdev, XenbusStateConnected);
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return 0;
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}
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static u32 xennet_xdp_query(struct net_device *dev)
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{
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unsigned int num_queues = dev->real_num_tx_queues;
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struct netfront_info *np = netdev_priv(dev);
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const struct bpf_prog *xdp_prog;
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struct netfront_queue *queue;
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unsigned int i;
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for (i = 0; i < num_queues; ++i) {
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queue = &np->queues[i];
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xdp_prog = rtnl_dereference(queue->xdp_prog);
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if (xdp_prog)
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return xdp_prog->aux->id;
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}
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return 0;
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}
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static int xennet_xdp(struct net_device *dev, struct netdev_bpf *xdp)
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{
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switch (xdp->command) {
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case XDP_SETUP_PROG:
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return xennet_xdp_set(dev, xdp->prog, xdp->extack);
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case XDP_QUERY_PROG:
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xdp->prog_id = xennet_xdp_query(dev);
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return 0;
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default:
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return -EINVAL;
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}
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}
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static const struct net_device_ops xennet_netdev_ops = {
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.ndo_open = xennet_open,
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.ndo_stop = xennet_close,
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@ -1272,6 +1517,8 @@ static const struct net_device_ops xennet_netdev_ops = {
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.ndo_fix_features = xennet_fix_features,
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.ndo_set_features = xennet_set_features,
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.ndo_select_queue = xennet_select_queue,
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.ndo_bpf = xennet_xdp,
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.ndo_xdp_xmit = xennet_xdp_xmit,
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#ifdef CONFIG_NET_POLL_CONTROLLER
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.ndo_poll_controller = xennet_poll_controller,
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#endif
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@ -1331,6 +1578,7 @@ static struct net_device *xennet_create_dev(struct xenbus_device *dev)
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SET_NETDEV_DEV(netdev, &dev->dev);
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np->netdev = netdev;
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np->netfront_xdp_enabled = false;
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netif_carrier_off(netdev);
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@ -1419,6 +1667,8 @@ static void xennet_disconnect_backend(struct netfront_info *info)
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queue->rx_ring_ref = GRANT_INVALID_REF;
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queue->tx.sring = NULL;
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queue->rx.sring = NULL;
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page_pool_destroy(queue->page_pool);
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}
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}
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@ -1754,6 +2004,51 @@ static void xennet_destroy_queues(struct netfront_info *info)
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info->queues = NULL;
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}
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static int xennet_create_page_pool(struct netfront_queue *queue)
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{
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int err;
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struct page_pool_params pp_params = {
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.order = 0,
|
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.flags = 0,
|
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.pool_size = NET_RX_RING_SIZE,
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.nid = NUMA_NO_NODE,
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.dev = &queue->info->netdev->dev,
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.offset = XDP_PACKET_HEADROOM,
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.max_len = XEN_PAGE_SIZE - XDP_PACKET_HEADROOM,
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};
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queue->page_pool = page_pool_create(&pp_params);
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if (IS_ERR(queue->page_pool)) {
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err = PTR_ERR(queue->page_pool);
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queue->page_pool = NULL;
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return err;
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}
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err = xdp_rxq_info_reg(&queue->xdp_rxq, queue->info->netdev,
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queue->id);
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if (err) {
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netdev_err(queue->info->netdev, "xdp_rxq_info_reg failed\n");
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goto err_free_pp;
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}
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err = xdp_rxq_info_reg_mem_model(&queue->xdp_rxq,
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MEM_TYPE_PAGE_POOL, queue->page_pool);
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if (err) {
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netdev_err(queue->info->netdev, "xdp_rxq_info_reg_mem_model failed\n");
|
||||
goto err_unregister_rxq;
|
||||
}
|
||||
return 0;
|
||||
|
||||
err_unregister_rxq:
|
||||
xdp_rxq_info_unreg(&queue->xdp_rxq);
|
||||
err_free_pp:
|
||||
page_pool_destroy(queue->page_pool);
|
||||
queue->page_pool = NULL;
|
||||
return err;
|
||||
}
|
||||
|
||||
static int xennet_create_queues(struct netfront_info *info,
|
||||
unsigned int *num_queues)
|
||||
{
|
||||
|
|
@ -1779,6 +2074,14 @@ static int xennet_create_queues(struct netfront_info *info,
|
|||
break;
|
||||
}
|
||||
|
||||
/* use page pool recycling instead of buddy allocator */
|
||||
ret = xennet_create_page_pool(queue);
|
||||
if (ret < 0) {
|
||||
dev_err(&info->xbdev->dev, "can't allocate page pool\n");
|
||||
*num_queues = i;
|
||||
return ret;
|
||||
}
|
||||
|
||||
netif_napi_add(queue->info->netdev, &queue->napi,
|
||||
xennet_poll, 64);
|
||||
if (netif_running(info->netdev))
|
||||
|
|
@ -1825,6 +2128,17 @@ static int talk_to_netback(struct xenbus_device *dev,
|
|||
goto out_unlocked;
|
||||
}
|
||||
|
||||
info->netback_has_xdp_headroom = xenbus_read_unsigned(info->xbdev->otherend,
|
||||
"feature-xdp-headroom", 0);
|
||||
if (info->netback_has_xdp_headroom) {
|
||||
/* set the current xen-netfront xdp state */
|
||||
err = talk_to_netback_xdp(info, info->netfront_xdp_enabled ?
|
||||
NETBACK_XDP_HEADROOM_ENABLE :
|
||||
NETBACK_XDP_HEADROOM_DISABLE);
|
||||
if (err)
|
||||
goto out_unlocked;
|
||||
}
|
||||
|
||||
rtnl_lock();
|
||||
if (info->queues)
|
||||
xennet_destroy_queues(info);
|
||||
|
|
@ -1959,6 +2273,8 @@ static int xennet_connect(struct net_device *dev)
|
|||
err = talk_to_netback(np->xbdev, np);
|
||||
if (err)
|
||||
return err;
|
||||
if (np->netback_has_xdp_headroom)
|
||||
pr_info("backend supports XDP headroom\n");
|
||||
|
||||
/* talk_to_netback() sets the correct number of queues */
|
||||
num_queues = dev->real_num_tx_queues;
|
||||
|
|
|
|||
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