/* A simple network driver using virtio. * * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ //#define DEBUG #include <linux/netdevice.h> #include <linux/etherdevice.h> #include <linux/ethtool.h> #include <linux/module.h> #include <linux/virtio.h> #include <linux/virtio_net.h> #include <linux/scatterlist.h> static int napi_weight = 128; module_param(napi_weight, int, 0444); static int csum = 1, gso = 1; module_param(csum, bool, 0444); module_param(gso, bool, 0444); /* FIXME: MTU in config. */ #define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN) struct virtnet_info { struct virtio_device *vdev; struct virtqueue *rvq, *svq; struct net_device *dev; struct napi_struct napi; /* The skb we couldn't send because buffers were full. */ struct sk_buff *last_xmit_skb; /* If we need to free in a timer, this is it. */ struct timer_list xmit_free_timer; /* Number of input buffers, and max we've ever had. */ unsigned int num, max; /* For cleaning up after transmission. */ struct tasklet_struct tasklet; bool free_in_tasklet; /* I like... big packets and I cannot lie! */ bool big_packets; /* Receive & send queues. */ struct sk_buff_head recv; struct sk_buff_head send; /* Chain pages by the private ptr. */ struct page *pages; }; static inline struct virtio_net_hdr *skb_vnet_hdr(struct sk_buff *skb) { return (struct virtio_net_hdr *)skb->cb; } static inline void vnet_hdr_to_sg(struct scatterlist *sg, struct sk_buff *skb) { sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr)); } static void give_a_page(struct virtnet_info *vi, struct page *page) { page->private = (unsigned long)vi->pages; vi->pages = page; } static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask) { struct page *p = vi->pages; if (p) vi->pages = (struct page *)p->private; else p = alloc_page(gfp_mask); return p; } static void skb_xmit_done(struct virtqueue *svq) { struct virtnet_info *vi = svq->vdev->priv; /* Suppress further interrupts. */ svq->vq_ops->disable_cb(svq); /* We were probably waiting for more output buffers. */ netif_wake_queue(vi->dev); /* Make sure we re-xmit last_xmit_skb: if there are no more packets * queued, start_xmit won't be called. */ tasklet_schedule(&vi->tasklet); } static void receive_skb(struct net_device *dev, struct sk_buff *skb, unsigned len) { struct virtio_net_hdr *hdr = skb_vnet_hdr(skb); int err; if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) { pr_debug("%s: short packet %i\n", dev->name, len); dev->stats.rx_length_errors++; goto drop; } len -= sizeof(struct virtio_net_hdr); if (len <= MAX_PACKET_LEN) { unsigned int i; for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) give_a_page(dev->priv, skb_shinfo(skb)->frags[i].page); skb->data_len = 0; skb_shinfo(skb)->nr_frags = 0; } err = pskb_trim(skb, len); if (err) { pr_debug("%s: pskb_trim failed %i %d\n", dev->name, len, err); dev->stats.rx_dropped++; goto drop; } skb->truesize += skb->data_len; dev->stats.rx_bytes += skb->len; dev->stats.rx_packets++; if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { pr_debug("Needs csum!\n"); if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset)) goto frame_err; } skb->protocol = eth_type_trans(skb, dev); pr_debug("Receiving skb proto 0x%04x len %i type %i\n", ntohs(skb->protocol), skb->len, skb->pkt_type); if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { pr_debug("GSO!\n"); switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { case VIRTIO_NET_HDR_GSO_TCPV4: skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; break; case VIRTIO_NET_HDR_GSO_UDP: skb_shinfo(skb)->gso_type = SKB_GSO_UDP; break; case VIRTIO_NET_HDR_GSO_TCPV6: skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; break; default: if (net_ratelimit()) printk(KERN_WARNING "%s: bad gso type %u.\n", dev->name, hdr->gso_type); goto frame_err; } if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN) skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; skb_shinfo(skb)->gso_size = hdr->gso_size; if (skb_shinfo(skb)->gso_size == 0) { if (net_ratelimit()) printk(KERN_WARNING "%s: zero gso size.\n", dev->name); goto frame_err; } /* Header must be checked, and gso_segs computed. */ skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; skb_shinfo(skb)->gso_segs = 0; } netif_receive_skb(skb); return; frame_err: dev->stats.rx_frame_errors++; drop: dev_kfree_skb(skb); } static void try_fill_recv(struct virtnet_info *vi) { struct sk_buff *skb; struct scatterlist sg[2+MAX_SKB_FRAGS]; int num, err, i; sg_init_table(sg, 2+MAX_SKB_FRAGS); for (;;) { skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN); if (unlikely(!skb)) break; skb_put(skb, MAX_PACKET_LEN); vnet_hdr_to_sg(sg, skb); if (vi->big_packets) { for (i = 0; i < MAX_SKB_FRAGS; i++) { skb_frag_t *f = &skb_shinfo(skb)->frags[i]; f->page = get_a_page(vi, GFP_ATOMIC); if (!f->page) break; f->page_offset = 0; f->size = PAGE_SIZE; skb->data_len += PAGE_SIZE; skb->len += PAGE_SIZE; skb_shinfo(skb)->nr_frags++; } } num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1; skb_queue_head(&vi->recv, skb); err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb); if (err) { skb_unlink(skb, &vi->recv); kfree_skb(skb); break; } vi->num++; } if (unlikely(vi->num > vi->max)) vi->max = vi->num; vi->rvq->vq_ops->kick(vi->rvq); } static void skb_recv_done(struct virtqueue *rvq) { struct virtnet_info *vi = rvq->vdev->priv; /* Schedule NAPI, Suppress further interrupts if successful. */ if (netif_rx_schedule_prep(vi->dev, &vi->napi)) { rvq->vq_ops->disable_cb(rvq); __netif_rx_schedule(vi->dev, &vi->napi); } } static int virtnet_poll(struct napi_struct *napi, int budget) { struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi); struct sk_buff *skb = NULL; unsigned int len, received = 0; again: while (received < budget && (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) { __skb_unlink(skb, &vi->recv); receive_skb(vi->dev, skb, len); vi->num--; received++; } /* FIXME: If we oom and completely run out of inbufs, we need * to start a timer trying to fill more. */ if (vi->num < vi->max / 2) try_fill_recv(vi); /* Out of packets? */ if (received < budget) { netif_rx_complete(vi->dev, napi); if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq)) && napi_schedule_prep(napi)) { vi->rvq->vq_ops->disable_cb(vi->rvq); __netif_rx_schedule(vi->dev, napi); goto again; } } return received; } static void free_old_xmit_skbs(struct virtnet_info *vi) { struct sk_buff *skb; unsigned int len; while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) { pr_debug("Sent skb %p\n", skb); __skb_unlink(skb, &vi->send); vi->dev->stats.tx_bytes += skb->len; vi->dev->stats.tx_packets++; kfree_skb(skb); } } /* If the virtio transport doesn't always notify us when all in-flight packets * are consumed, we fall back to using this function on a timer to free them. */ static void xmit_free(unsigned long data) { struct virtnet_info *vi = (void *)data; netif_tx_lock(vi->dev); free_old_xmit_skbs(vi); if (!skb_queue_empty(&vi->send)) mod_timer(&vi->xmit_free_timer, jiffies + (HZ/10)); netif_tx_unlock(vi->dev); } static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb) { int num, err; struct scatterlist sg[2+MAX_SKB_FRAGS]; struct virtio_net_hdr *hdr; const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest; sg_init_table(sg, 2+MAX_SKB_FRAGS); pr_debug("%s: xmit %p " MAC_FMT "\n", vi->dev->name, skb, dest[0], dest[1], dest[2], dest[3], dest[4], dest[5]); /* Encode metadata header at front. */ hdr = skb_vnet_hdr(skb); if (skb->ip_summed == CHECKSUM_PARTIAL) { hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; hdr->csum_start = skb->csum_start - skb_headroom(skb); hdr->csum_offset = skb->csum_offset; } else { hdr->flags = 0; hdr->csum_offset = hdr->csum_start = 0; } if (skb_is_gso(skb)) { hdr->hdr_len = skb_transport_header(skb) - skb->data; hdr->gso_size = skb_shinfo(skb)->gso_size; if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP) hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP; else BUG(); if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN) hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN; } else { hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; hdr->gso_size = hdr->hdr_len = 0; } vnet_hdr_to_sg(sg, skb); num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1; err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb); if (!err && !vi->free_in_tasklet) mod_timer(&vi->xmit_free_timer, jiffies + (HZ/10)); return err; } static void xmit_tasklet(unsigned long data) { struct virtnet_info *vi = (void *)data; netif_tx_lock_bh(vi->dev); if (vi->last_xmit_skb && xmit_skb(vi, vi->last_xmit_skb) == 0) { vi->svq->vq_ops->kick(vi->svq); vi->last_xmit_skb = NULL; } if (vi->free_in_tasklet) free_old_xmit_skbs(vi); netif_tx_unlock_bh(vi->dev); } static int start_xmit(struct sk_buff *skb, struct net_device *dev) { struct virtnet_info *vi = netdev_priv(dev); again: /* Free up any pending old buffers before queueing new ones. */ free_old_xmit_skbs(vi); /* If we has a buffer left over from last time, send it now. */ if (unlikely(vi->last_xmit_skb) && xmit_skb(vi, vi->last_xmit_skb) != 0) goto stop_queue; vi->last_xmit_skb = NULL; /* Put new one in send queue and do transmit */ if (likely(skb)) { __skb_queue_head(&vi->send, skb); if (xmit_skb(vi, skb) != 0) { vi->last_xmit_skb = skb; skb = NULL; goto stop_queue; } } done: vi->svq->vq_ops->kick(vi->svq); return NETDEV_TX_OK; stop_queue: pr_debug("%s: virtio not prepared to send\n", dev->name); netif_stop_queue(dev); /* Activate callback for using skbs: if this returns false it * means some were used in the meantime. */ if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) { vi->svq->vq_ops->disable_cb(vi->svq); netif_start_queue(dev); goto again; } if (skb) { /* Drop this skb: we only queue one. */ vi->dev->stats.tx_dropped++; kfree_skb(skb); } goto done; } #ifdef CONFIG_NET_POLL_CONTROLLER static void virtnet_netpoll(struct net_device *dev) { struct virtnet_info *vi = netdev_priv(dev); napi_schedule(&vi->napi); } #endif static int virtnet_open(struct net_device *dev) { struct virtnet_info *vi = netdev_priv(dev); napi_enable(&vi->napi); /* If all buffers were filled by other side before we napi_enabled, we * won't get another interrupt, so process any outstanding packets * now. virtnet_poll wants re-enable the queue, so we disable here. * We synchronize against interrupts via NAPI_STATE_SCHED */ if (netif_rx_schedule_prep(dev, &vi->napi)) { vi->rvq->vq_ops->disable_cb(vi->rvq); __netif_rx_schedule(dev, &vi->napi); } return 0; } static int virtnet_close(struct net_device *dev) { struct virtnet_info *vi = netdev_priv(dev); napi_disable(&vi->napi); return 0; } static int virtnet_set_tx_csum(struct net_device *dev, u32 data) { struct virtnet_info *vi = netdev_priv(dev); struct virtio_device *vdev = vi->vdev; if (data && !virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) return -ENOSYS; return ethtool_op_set_tx_hw_csum(dev, data); } static struct ethtool_ops virtnet_ethtool_ops = { .set_tx_csum = virtnet_set_tx_csum, .set_sg = ethtool_op_set_sg, }; static int virtnet_probe(struct virtio_device *vdev) { int err; struct net_device *dev; struct virtnet_info *vi; /* Allocate ourselves a network device with room for our info */ dev = alloc_etherdev(sizeof(struct virtnet_info)); if (!dev) return -ENOMEM; /* Set up network device as normal. */ dev->open = virtnet_open; dev->stop = virtnet_close; dev->hard_start_xmit = start_xmit; dev->features = NETIF_F_HIGHDMA; #ifdef CONFIG_NET_POLL_CONTROLLER dev->poll_controller = virtnet_netpoll; #endif SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops); SET_NETDEV_DEV(dev, &vdev->dev); /* Do we support "hardware" checksums? */ if (csum && virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) { /* This opens up the world of extra features. */ dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST; if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) { dev->features |= NETIF_F_TSO | NETIF_F_UFO | NETIF_F_TSO_ECN | NETIF_F_TSO6; } /* Individual feature bits: what can host handle? */ if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4)) dev->features |= NETIF_F_TSO; if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6)) dev->features |= NETIF_F_TSO6; if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN)) dev->features |= NETIF_F_TSO_ECN; if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO)) dev->features |= NETIF_F_UFO; } /* Configuration may specify what MAC to use. Otherwise random. */ if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) { vdev->config->get(vdev, offsetof(struct virtio_net_config, mac), dev->dev_addr, dev->addr_len); } else random_ether_addr(dev->dev_addr); /* Set up our device-specific information */ vi = netdev_priv(dev); netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight); vi->dev = dev; vi->vdev = vdev; vdev->priv = vi; vi->pages = NULL; /* If they give us a callback when all buffers are done, we don't need * the timer. */ vi->free_in_tasklet = virtio_has_feature(vdev,VIRTIO_F_NOTIFY_ON_EMPTY); /* If we can receive ANY GSO packets, we must allocate large ones. */ if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN)) vi->big_packets = true; /* We expect two virtqueues, receive then send. */ vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done); if (IS_ERR(vi->rvq)) { err = PTR_ERR(vi->rvq); goto free; } vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done); if (IS_ERR(vi->svq)) { err = PTR_ERR(vi->svq); goto free_recv; } /* Initialize our empty receive and send queues. */ skb_queue_head_init(&vi->recv); skb_queue_head_init(&vi->send); tasklet_init(&vi->tasklet, xmit_tasklet, (unsigned long)vi); if (!vi->free_in_tasklet) setup_timer(&vi->xmit_free_timer, xmit_free, (unsigned long)vi); err = register_netdev(dev); if (err) { pr_debug("virtio_net: registering device failed\n"); goto free_send; } /* Last of all, set up some receive buffers. */ try_fill_recv(vi); /* If we didn't even get one input buffer, we're useless. */ if (vi->num == 0) { err = -ENOMEM; goto unregister; } pr_debug("virtnet: registered device %s\n", dev->name); return 0; unregister: unregister_netdev(dev); free_send: vdev->config->del_vq(vi->svq); free_recv: vdev->config->del_vq(vi->rvq); free: free_netdev(dev); return err; } static void virtnet_remove(struct virtio_device *vdev) { struct virtnet_info *vi = vdev->priv; struct sk_buff *skb; /* Stop all the virtqueues. */ vdev->config->reset(vdev); if (!vi->free_in_tasklet) del_timer_sync(&vi->xmit_free_timer); /* Free our skbs in send and recv queues, if any. */ while ((skb = __skb_dequeue(&vi->recv)) != NULL) { kfree_skb(skb); vi->num--; } __skb_queue_purge(&vi->send); BUG_ON(vi->num != 0); vdev->config->del_vq(vi->svq); vdev->config->del_vq(vi->rvq); unregister_netdev(vi->dev); while (vi->pages) __free_pages(get_a_page(vi, GFP_KERNEL), 0); free_netdev(vi->dev); } static struct virtio_device_id id_table[] = { { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID }, { 0 }, }; static unsigned int features[] = { VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM, VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC, VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6, VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6, VIRTIO_NET_F_GUEST_ECN, /* We don't yet handle UFO input. */ VIRTIO_F_NOTIFY_ON_EMPTY, }; static struct virtio_driver virtio_net = { .feature_table = features, .feature_table_size = ARRAY_SIZE(features), .driver.name = KBUILD_MODNAME, .driver.owner = THIS_MODULE, .id_table = id_table, .probe = virtnet_probe, .remove = __devexit_p(virtnet_remove), }; static int __init init(void) { return register_virtio_driver(&virtio_net); } static void __exit fini(void) { unregister_virtio_driver(&virtio_net); } module_init(init); module_exit(fini); MODULE_DEVICE_TABLE(virtio, id_table); MODULE_DESCRIPTION("Virtio network driver"); MODULE_LICENSE("GPL");