diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/Kconfig | 6 | ||||
| -rw-r--r-- | drivers/net/Makefile | 1 | ||||
| -rw-r--r-- | drivers/net/virtio_net.c | 435 |
3 files changed, 442 insertions, 0 deletions
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index ce34b539bf38..2538816817aa 100644 --- a/drivers/net/Kconfig +++ b/drivers/net/Kconfig @@ -3100,4 +3100,10 @@ config NETPOLL_TRAP config NET_POLL_CONTROLLER def_bool NETPOLL +config VIRTIO_NET + tristate "Virtio network driver (EXPERIMENTAL)" + depends on EXPERIMENTAL && VIRTIO + ---help--- + This is the virtual network driver for lguest. Say Y or M. + endif # NETDEVICES diff --git a/drivers/net/Makefile b/drivers/net/Makefile index 22f78cbd126b..6745feb690ff 100644 --- a/drivers/net/Makefile +++ b/drivers/net/Makefile @@ -243,3 +243,4 @@ obj-$(CONFIG_FS_ENET) += fs_enet/ obj-$(CONFIG_NETXEN_NIC) += netxen/ obj-$(CONFIG_NIU) += niu.o +obj-$(CONFIG_VIRTIO_NET) += virtio_net.o diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c new file mode 100644 index 000000000000..e396c9d2af8d --- /dev/null +++ b/drivers/net/virtio_net.c @@ -0,0 +1,435 @@ +/* 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/module.h> +#include <linux/virtio.h> +#include <linux/virtio_net.h> +#include <linux/scatterlist.h> + +/* 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; + + /* Number of input buffers, and max we've ever had. */ + unsigned int num, max; + + /* Receive & send queues. */ + struct sk_buff_head recv; + struct sk_buff_head send; +}; + +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 bool skb_xmit_done(struct virtqueue *rvq) +{ + struct virtnet_info *vi = rvq->vdev->priv; + + /* In case we were waiting for output buffers. */ + netif_wake_queue(vi->dev); + return true; +} + +static void receive_skb(struct net_device *dev, struct sk_buff *skb, + unsigned len) +{ + struct virtio_net_hdr *hdr = skb_vnet_hdr(skb); + + 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); + BUG_ON(len > MAX_PACKET_LEN); + + skb_trim(skb, len); + 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); + dev->stats.rx_bytes += skb->len; + dev->stats.rx_packets++; + + if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { + pr_debug("Needs csum!\n"); + skb->ip_summed = CHECKSUM_PARTIAL; + skb->csum_start = hdr->csum_start; + skb->csum_offset = hdr->csum_offset; + if (skb->csum_start > skb->len - 2 + || skb->csum_offset > skb->len - 2) { + if (net_ratelimit()) + printk(KERN_WARNING "%s: csum=%u/%u len=%u\n", + dev->name, skb->csum_start, + skb->csum_offset, skb->len); + goto frame_err; + } + } + + if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { + pr_debug("GSO!\n"); + switch (hdr->gso_type) { + case VIRTIO_NET_HDR_GSO_TCPV4: + skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; + break; + case VIRTIO_NET_HDR_GSO_TCPV4_ECN: + skb_shinfo(skb)->gso_type = SKB_GSO_TCP_ECN; + 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; + } + + 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[1+MAX_SKB_FRAGS]; + int num, err; + + 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); + 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 bool skb_recv_done(struct virtqueue *rvq) +{ + struct virtnet_info *vi = rvq->vdev->priv; + netif_rx_schedule(vi->dev, &vi->napi); + /* Suppress further interrupts. */ + return false; +} + +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); + + /* All done? */ + if (!skb) { + netif_rx_complete(vi->dev, napi); + if (unlikely(!vi->rvq->vq_ops->restart(vi->rvq)) + && netif_rx_reschedule(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 += len; + vi->dev->stats.tx_packets++; + kfree_skb(skb); + } +} + +static int start_xmit(struct sk_buff *skb, struct net_device *dev) +{ + struct virtnet_info *vi = netdev_priv(dev); + int num, err; + struct scatterlist sg[1+MAX_SKB_FRAGS]; + struct virtio_net_hdr *hdr; + const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest; + DECLARE_MAC_BUF(mac); + + pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest)); + + free_old_xmit_skbs(vi); + + /* 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->gso_size = skb_shinfo(skb)->gso_size; + if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN) + hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4_ECN; + else 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(); + } else { + hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; + hdr->gso_size = 0; + } + + vnet_hdr_to_sg(sg, skb); + num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1; + __skb_queue_head(&vi->send, skb); + err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb); + if (err) { + pr_debug("%s: virtio not prepared to send\n", dev->name); + skb_unlink(skb, &vi->send); + netif_stop_queue(dev); + return NETDEV_TX_BUSY; + } + vi->svq->vq_ops->kick(vi->svq); + + return 0; +} + +static int virtnet_open(struct net_device *dev) +{ + struct virtnet_info *vi = netdev_priv(dev); + + try_fill_recv(vi); + + /* If we didn't even get one input buffer, we're useless. */ + if (vi->num == 0) + return -ENOMEM; + + napi_enable(&vi->napi); + return 0; +} + +static int virtnet_close(struct net_device *dev) +{ + struct virtnet_info *vi = netdev_priv(dev); + struct sk_buff *skb; + + napi_disable(&vi->napi); + + /* networking core has neutered skb_xmit_done/skb_recv_done, so don't + * worry about races vs. get(). */ + vi->rvq->vq_ops->shutdown(vi->rvq); + while ((skb = __skb_dequeue(&vi->recv)) != NULL) { + kfree_skb(skb); + vi->num--; + } + vi->svq->vq_ops->shutdown(vi->svq); + while ((skb = __skb_dequeue(&vi->send)) != NULL) + kfree_skb(skb); + + BUG_ON(vi->num != 0); + return 0; +} + +static int virtnet_probe(struct virtio_device *vdev) +{ + int err; + unsigned int len; + struct net_device *dev; + struct virtnet_info *vi; + void *token; + + /* 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. */ + ether_setup(dev); + dev->open = virtnet_open; + dev->stop = virtnet_close; + dev->hard_start_xmit = start_xmit; + dev->features = NETIF_F_HIGHDMA; + SET_NETDEV_DEV(dev, &vdev->dev); + + /* Do we support "hardware" checksums? */ + token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_F, &len); + if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_NO_CSUM)) { + /* This opens up the world of extra features. */ + dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST; + if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4)) + dev->features |= NETIF_F_TSO; + if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_UFO)) + dev->features |= NETIF_F_UFO; + if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4_ECN)) + dev->features |= NETIF_F_TSO_ECN; + if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO6)) + dev->features |= NETIF_F_TSO6; + } + + /* Configuration may specify what MAC to use. Otherwise random. */ + token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_MAC_F, &len); + if (token) { + dev->addr_len = len; + vdev->config->get(vdev, token, dev->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, 16); + vi->dev = dev; + vi->vdev = vdev; + + /* We expect two virtqueues, receive then send. */ + vi->rvq = vdev->config->find_vq(vdev, skb_recv_done); + if (IS_ERR(vi->rvq)) { + err = PTR_ERR(vi->rvq); + goto free; + } + + vi->svq = vdev->config->find_vq(vdev, 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); + + err = register_netdev(dev); + if (err) { + pr_debug("virtio_net: registering device failed\n"); + goto free_send; + } + pr_debug("virtnet: registered device %s\n", dev->name); + vdev->priv = vi; + return 0; + +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) +{ + unregister_netdev(vdev->priv); + free_netdev(vdev->priv); +} + +static struct virtio_device_id id_table[] = { + { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID }, + { 0 }, +}; + +static struct virtio_driver virtio_net = { + .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"); |