drivers/net/virtio_net.c

   1 /* A network driver using virtio.
   2  *
   3  * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19 //#define DEBUG
  20 #include <linux/netdevice.h>
  21 #include <linux/etherdevice.h>
  22 #include <linux/ethtool.h>
  23 #include <linux/module.h>
  24 #include <linux/virtio.h>
  25 #include <linux/virtio_net.h>
  26 #include <linux/scatterlist.h>
  27 #include <linux/if_vlan.h>
  28
  29 static int napi_weight = 128;
  30 module_param(napi_weight, int, 0444);
  31
  32 static int csum = 1, gso = 1;
  33 module_param(csum, bool, 0444);
  34 module_param(gso, bool, 0444);
  35
  36 /* FIXME: MTU in config. */
  37 #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
  38 #define GOOD_COPY_LEN   128
  39
  40 #define VIRTNET_SEND_COMMAND_SG_MAX    2
  41
  42 struct virtnet_info
  43 {
  44         struct virtio_device *vdev;
  45         struct virtqueue *rvq, *svq, *cvq;
  46         struct net_device *dev;
  47         struct napi_struct napi;
  48         unsigned int status;
  49
  50         /* Number of input buffers, and max we've ever had. */
  51         unsigned int num, max;
  52
  53         /* I like... big packets and I cannot lie! */
  54         bool big_packets;
  55
  56         /* Host will merge rx buffers for big packets (shake it! shake it!) */
  57         bool mergeable_rx_bufs;
  58
  59         /* Receive & send queues. */
  60         struct sk_buff_head recv;
  61         struct sk_buff_head send;
  62
  63         /* Work struct for refilling if we run low on memory. */
  64         struct delayed_work refill;
  65
  66         /* Chain pages by the private ptr. */
  67         struct page *pages;
  68 };
  69
  70 struct skb_vnet_hdr {
  71         union {
  72                 struct virtio_net_hdr hdr;
  73                 struct virtio_net_hdr_mrg_rxbuf mhdr;
  74         };
  75         unsigned int num_sg;
  76 };
  77
  78 static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
  79 {
  80         return (struct skb_vnet_hdr *)skb->cb;
  81 }
  82
  83 static void give_a_page(struct virtnet_info *vi, struct page *page)
  84 {
  85         page->private = (unsigned long)vi->pages;
  86         vi->pages = page;
  87 }
  88
  89 static void trim_pages(struct virtnet_info *vi, struct sk_buff *skb)
  90 {
  91         unsigned int i;
  92
  93         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
  94                 give_a_page(vi, skb_shinfo(skb)->frags[i].page);
  95         skb_shinfo(skb)->nr_frags = 0;
  96         skb->data_len = 0;
  97 }
  98
  99 static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
 100 {
 101         struct page *p = vi->pages;
 102
 103         if (p)
 104                 vi->pages = (struct page *)p->private;
 105         else
 106                 p = alloc_page(gfp_mask);
 107         return p;
 108 }
 109
 110 static void skb_xmit_done(struct virtqueue *svq)
 111 {
 112         struct virtnet_info *vi = svq->vdev->priv;
 113
 114         /* Suppress further interrupts. */
 115         svq->vq_ops->disable_cb(svq);
 116
 117         /* We were probably waiting for more output buffers. */
 118         netif_wake_queue(vi->dev);
 119 }
 120
 121 static void receive_skb(struct net_device *dev, struct sk_buff *skb,
 122                         unsigned len)
 123 {
 124         struct virtnet_info *vi = netdev_priv(dev);
 125         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 126         int err;
 127         int i;
 128
 129         if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
 130                 pr_debug("%s: short packet %i\n", dev->name, len);
 131                 dev->stats.rx_length_errors++;
 132                 goto drop;
 133         }
 134
 135         if (vi->mergeable_rx_bufs) {
 136                 unsigned int copy;
 137                 char *p = page_address(skb_shinfo(skb)->frags[0].page);
 138
 139                 if (len > PAGE_SIZE)
 140                         len = PAGE_SIZE;
 141                 len -= sizeof(struct virtio_net_hdr_mrg_rxbuf);
 142
 143                 memcpy(&hdr->mhdr, p, sizeof(hdr->mhdr));
 144                 p += sizeof(hdr->mhdr);
 145
 146                 copy = len;
 147                 if (copy > skb_tailroom(skb))
 148                         copy = skb_tailroom(skb);
 149
 150                 memcpy(skb_put(skb, copy), p, copy);
 151
 152                 len -= copy;
 153
 154                 if (!len) {
 155                         give_a_page(vi, skb_shinfo(skb)->frags[0].page);
 156                         skb_shinfo(skb)->nr_frags--;
 157                 } else {
 158                         skb_shinfo(skb)->frags[0].page_offset +=
 159                                 sizeof(hdr->mhdr) + copy;
 160                         skb_shinfo(skb)->frags[0].size = len;
 161                         skb->data_len += len;
 162                         skb->len += len;
 163                 }
 164
 165                 while (--hdr->mhdr.num_buffers) {
 166                         struct sk_buff *nskb;
 167
 168                         i = skb_shinfo(skb)->nr_frags;
 169                         if (i >= MAX_SKB_FRAGS) {
 170                                 pr_debug("%s: packet too long %d\n", dev->name,
 171                                          len);
 172                                 dev->stats.rx_length_errors++;
 173                                 goto drop;
 174                         }
 175
 176                         nskb = vi->rvq->vq_ops->get_buf(vi->rvq, &len);
 177                         if (!nskb) {
 178                                 pr_debug("%s: rx error: %d buffers missing\n",
 179                                          dev->name, hdr->mhdr.num_buffers);
 180                                 dev->stats.rx_length_errors++;
 181                                 goto drop;
 182                         }
 183
 184                         __skb_unlink(nskb, &vi->recv);
 185                         vi->num--;
 186
 187                         skb_shinfo(skb)->frags[i] = skb_shinfo(nskb)->frags[0];
 188                         skb_shinfo(nskb)->nr_frags = 0;
 189                         kfree_skb(nskb);
 190
 191                         if (len > PAGE_SIZE)
 192                                 len = PAGE_SIZE;
 193
 194                         skb_shinfo(skb)->frags[i].size = len;
 195                         skb_shinfo(skb)->nr_frags++;
 196                         skb->data_len += len;
 197                         skb->len += len;
 198                 }
 199         } else {
 200                 len -= sizeof(hdr->hdr);
 201
 202                 if (len <= MAX_PACKET_LEN)
 203                         trim_pages(vi, skb);
 204
 205                 err = pskb_trim(skb, len);
 206                 if (err) {
 207                         pr_debug("%s: pskb_trim failed %i %d\n", dev->name,
 208                                  len, err);
 209                         dev->stats.rx_dropped++;
 210                         goto drop;
 211                 }
 212         }
 213
 214         skb->truesize += skb->data_len;
 215         dev->stats.rx_bytes += skb->len;
 216         dev->stats.rx_packets++;
 217
 218         if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 219                 pr_debug("Needs csum!\n");
 220                 if (!skb_partial_csum_set(skb,
 221                                           hdr->hdr.csum_start,
 222                                           hdr->hdr.csum_offset))
 223                         goto frame_err;
 224         }
 225
 226         skb->protocol = eth_type_trans(skb, dev);
 227         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
 228                  ntohs(skb->protocol), skb->len, skb->pkt_type);
 229
 230         if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 231                 pr_debug("GSO!\n");
 232                 switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 233                 case VIRTIO_NET_HDR_GSO_TCPV4:
 234                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 235                         break;
 236                 case VIRTIO_NET_HDR_GSO_UDP:
 237                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 238                         break;
 239                 case VIRTIO_NET_HDR_GSO_TCPV6:
 240                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 241                         break;
 242                 default:
 243                         if (net_ratelimit())
 244                                 printk(KERN_WARNING "%s: bad gso type %u.\n",
 245                                        dev->name, hdr->hdr.gso_type);
 246                         goto frame_err;
 247                 }
 248
 249                 if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 250                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 251
 252                 skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
 253                 if (skb_shinfo(skb)->gso_size == 0) {
 254                         if (net_ratelimit())
 255                                 printk(KERN_WARNING "%s: zero gso size.\n",
 256                                        dev->name);
 257                         goto frame_err;
 258                 }
 259
 260                 /* Header must be checked, and gso_segs computed. */
 261                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 262                 skb_shinfo(skb)->gso_segs = 0;
 263         }
 264
 265         netif_receive_skb(skb);
 266         return;
 267
 268 frame_err:
 269         dev->stats.rx_frame_errors++;
 270 drop:
 271         dev_kfree_skb(skb);
 272 }
 273
 274 static bool try_fill_recv_maxbufs(struct virtnet_info *vi, gfp_t gfp)
 275 {
 276         struct sk_buff *skb;
 277         struct scatterlist sg[2+MAX_SKB_FRAGS];
 278         int num, err, i;
 279         bool oom = false;
 280
 281         sg_init_table(sg, 2+MAX_SKB_FRAGS);
 282         do {
 283                 struct skb_vnet_hdr *hdr;
 284
 285                 skb = netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN);
 286                 if (unlikely(!skb)) {
 287                         oom = true;
 288                         break;
 289                 }
 290
 291                 skb_put(skb, MAX_PACKET_LEN);
 292
 293                 hdr = skb_vnet_hdr(skb);
 294                 sg_set_buf(sg, &hdr->hdr, sizeof(hdr->hdr));
 295
 296                 if (vi->big_packets) {
 297                         for (i = 0; i < MAX_SKB_FRAGS; i++) {
 298                                 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
 299                                 f->page = get_a_page(vi, gfp);
 300                                 if (!f->page)
 301                                         break;
 302
 303                                 f->page_offset = 0;
 304                                 f->size = PAGE_SIZE;
 305
 306                                 skb->data_len += PAGE_SIZE;
 307                                 skb->len += PAGE_SIZE;
 308
 309                                 skb_shinfo(skb)->nr_frags++;
 310                         }
 311                 }
 312
 313                 num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
 314                 skb_queue_head(&vi->recv, skb);
 315
 316                 err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
 317                 if (err < 0) {
 318                         skb_unlink(skb, &vi->recv);
 319                         trim_pages(vi, skb);
 320                         kfree_skb(skb);
 321                         break;
 322                 }
 323                 vi->num++;
 324         } while (err >= num);
 325         if (unlikely(vi->num > vi->max))
 326                 vi->max = vi->num;
 327         vi->rvq->vq_ops->kick(vi->rvq);
 328         return !oom;
 329 }
 330
 331 /* Returns false if we couldn't fill entirely (OOM). */
 332 static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
 333 {
 334         struct sk_buff *skb;
 335         struct scatterlist sg[1];
 336         int err;
 337         bool oom = false;
 338
 339         if (!vi->mergeable_rx_bufs)
 340                 return try_fill_recv_maxbufs(vi, gfp);
 341
 342         do {
 343                 skb_frag_t *f;
 344
 345                 skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
 346                 if (unlikely(!skb)) {
 347                         oom = true;
 348                         break;
 349                 }
 350
 351                 f = &skb_shinfo(skb)->frags[0];
 352                 f->page = get_a_page(vi, gfp);
 353                 if (!f->page) {
 354                         oom = true;
 355                         kfree_skb(skb);
 356                         break;
 357                 }
 358
 359                 f->page_offset = 0;
 360                 f->size = PAGE_SIZE;
 361
 362                 skb_shinfo(skb)->nr_frags++;
 363
 364                 sg_init_one(sg, page_address(f->page), PAGE_SIZE);
 365                 skb_queue_head(&vi->recv, skb);
 366
 367                 err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, 1, skb);
 368                 if (err < 0) {
 369                         skb_unlink(skb, &vi->recv);
 370                         kfree_skb(skb);
 371                         break;
 372                 }
 373                 vi->num++;
 374         } while (err > 0);
 375         if (unlikely(vi->num > vi->max))
 376                 vi->max = vi->num;
 377         vi->rvq->vq_ops->kick(vi->rvq);
 378         return !oom;
 379 }
 380
 381 static void skb_recv_done(struct virtqueue *rvq)
 382 {
 383         struct virtnet_info *vi = rvq->vdev->priv;
 384         /* Schedule NAPI, Suppress further interrupts if successful. */
 385         if (napi_schedule_prep(&vi->napi)) {
 386                 rvq->vq_ops->disable_cb(rvq);
 387                 __napi_schedule(&vi->napi);
 388         }
 389 }
 390
 391 static void refill_work(struct work_struct *work)
 392 {
 393         struct virtnet_info *vi;
 394         bool still_empty;
 395
 396         vi = container_of(work, struct virtnet_info, refill.work);
 397         napi_disable(&vi->napi);
 398         try_fill_recv(vi, GFP_KERNEL);
 399         still_empty = (vi->num == 0);
 400         napi_enable(&vi->napi);
 401
 402         /* In theory, this can happen: if we don't get any buffers in
 403          * we will *never* try to fill again. */
 404         if (still_empty)
 405                 schedule_delayed_work(&vi->refill, HZ/2);
 406 }
 407
 408 static int virtnet_poll(struct napi_struct *napi, int budget)
 409 {
 410         struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
 411         struct sk_buff *skb = NULL;
 412         unsigned int len, received = 0;
 413
 414 again:
 415         while (received < budget &&
 416                (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
 417                 __skb_unlink(skb, &vi->recv);
 418                 receive_skb(vi->dev, skb, len);
 419                 vi->num--;
 420                 received++;
 421         }
 422
 423         if (vi->num < vi->max / 2) {
 424                 if (!try_fill_recv(vi, GFP_ATOMIC))
 425                         schedule_delayed_work(&vi->refill, 0);
 426         }
 427
 428         /* Out of packets? */
 429         if (received < budget) {
 430                 napi_complete(napi);
 431                 if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq))
 432                     && napi_schedule_prep(napi)) {
 433                         vi->rvq->vq_ops->disable_cb(vi->rvq);
 434                         __napi_schedule(napi);
 435                         goto again;
 436                 }
 437         }
 438
 439         return received;
 440 }
 441
 442 static unsigned int free_old_xmit_skbs(struct virtnet_info *vi)
 443 {
 444         struct sk_buff *skb;
 445         unsigned int len, tot_sgs = 0;
 446
 447         while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
 448                 pr_debug("Sent skb %p\n", skb);
 449                 __skb_unlink(skb, &vi->send);
 450                 vi->dev->stats.tx_bytes += skb->len;
 451                 vi->dev->stats.tx_packets++;
 452                 tot_sgs += skb_vnet_hdr(skb)->num_sg;
 453                 dev_kfree_skb_any(skb);
 454         }
 455         return tot_sgs;
 456 }
 457
 458 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
 459 {
 460         struct scatterlist sg[2+MAX_SKB_FRAGS];
 461         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 462         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 463
 464         sg_init_table(sg, 2+MAX_SKB_FRAGS);
 465
 466         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
 467
 468         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 469                 hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 470                 hdr->hdr.csum_start = skb->csum_start - skb_headroom(skb);
 471                 hdr->hdr.csum_offset = skb->csum_offset;
 472         } else {
 473                 hdr->hdr.flags = 0;
 474                 hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
 475         }
 476
 477         if (skb_is_gso(skb)) {
 478                 hdr->hdr.hdr_len = skb_headlen(skb);
 479                 hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
 480                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 481                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 482                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 483                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 484                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 485                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 486                 else
 487                         BUG();
 488                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
 489                         hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 490         } else {
 491                 hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 492                 hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
 493         }
 494
 495         hdr->mhdr.num_buffers = 0;
 496
 497         /* Encode metadata header at front. */
 498         if (vi->mergeable_rx_bufs)
 499                 sg_set_buf(sg, &hdr->mhdr, sizeof(hdr->mhdr));
 500         else
 501                 sg_set_buf(sg, &hdr->hdr, sizeof(hdr->hdr));
 502
 503         hdr->num_sg = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
 504         return vi->svq->vq_ops->add_buf(vi->svq, sg, hdr->num_sg, 0, skb);
 505 }
 506
 507 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 508 {
 509         struct virtnet_info *vi = netdev_priv(dev);
 510         int capacity;
 511
 512 again:
 513         /* Free up any pending old buffers before queueing new ones. */
 514         free_old_xmit_skbs(vi);
 515
 516         /* Try to transmit */
 517         capacity = xmit_skb(vi, skb);
 518
 519         /* This can happen with OOM and indirect buffers. */
 520         if (unlikely(capacity < 0)) {
 521                 netif_stop_queue(dev);
 522                 dev_warn(&dev->dev, "Unexpected full queue\n");
 523                 if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
 524                         vi->svq->vq_ops->disable_cb(vi->svq);
 525                         netif_start_queue(dev);
 526                         goto again;
 527                 }
 528                 return NETDEV_TX_BUSY;
 529         }
 530         vi->svq->vq_ops->kick(vi->svq);
 531
 532         /*
 533          * Put new one in send queue.  You'd expect we'd need this before
 534          * xmit_skb calls add_buf(), since the callback can be triggered
 535          * immediately after that.  But since the callback just triggers
 536          * another call back here, normal network xmit locking prevents the
 537          * race.
 538          */
 539         __skb_queue_head(&vi->send, skb);
 540
 541         /* Don't wait up for transmitted skbs to be freed. */
 542         skb_orphan(skb);
 543         nf_reset(skb);
 544
 545         /* Apparently nice girls don't return TX_BUSY; stop the queue
 546          * before it gets out of hand.  Naturally, this wastes entries. */
 547         if (capacity < 2+MAX_SKB_FRAGS) {
 548                 netif_stop_queue(dev);
 549                 if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
 550                         /* More just got used, free them then recheck. */
 551                         capacity += free_old_xmit_skbs(vi);
 552                         if (capacity >= 2+MAX_SKB_FRAGS) {
 553                                 netif_start_queue(dev);
 554                                 vi->svq->vq_ops->disable_cb(vi->svq);
 555                         }
 556                 }
 557         }
 558
 559         return NETDEV_TX_OK;
 560 }
 561
 562 static int virtnet_set_mac_address(struct net_device *dev, void *p)
 563 {
 564         struct virtnet_info *vi = netdev_priv(dev);
 565         struct virtio_device *vdev = vi->vdev;
 566         int ret;
 567
 568         ret = eth_mac_addr(dev, p);
 569         if (ret)
 570                 return ret;
 571
 572         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
 573                 vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
 574                                   dev->dev_addr, dev->addr_len);
 575
 576         return 0;
 577 }
 578
 579 #ifdef CONFIG_NET_POLL_CONTROLLER
 580 static void virtnet_netpoll(struct net_device *dev)
 581 {
 582         struct virtnet_info *vi = netdev_priv(dev);
 583
 584         napi_schedule(&vi->napi);
 585 }
 586 #endif
 587
 588 static int virtnet_open(struct net_device *dev)
 589 {
 590         struct virtnet_info *vi = netdev_priv(dev);
 591
 592         napi_enable(&vi->napi);
 593
 594         /* If all buffers were filled by other side before we napi_enabled, we
 595          * won't get another interrupt, so process any outstanding packets
 596          * now.  virtnet_poll wants re-enable the queue, so we disable here.
 597          * We synchronize against interrupts via NAPI_STATE_SCHED */
 598         if (napi_schedule_prep(&vi->napi)) {
 599                 vi->rvq->vq_ops->disable_cb(vi->rvq);
 600                 __napi_schedule(&vi->napi);
 601         }
 602         return 0;
 603 }
 604
 605 /*
 606  * Send command via the control virtqueue and check status.  Commands
 607  * supported by the hypervisor, as indicated by feature bits, should
 608  * never fail unless improperly formated.
 609  */
 610 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
 611                                  struct scatterlist *data, int out, int in)
 612 {
 613         struct scatterlist *s, sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
 614         struct virtio_net_ctrl_hdr ctrl;
 615         virtio_net_ctrl_ack status = ~0;
 616         unsigned int tmp;
 617         int i;
 618
 619         /* Caller should know better */
 620         BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ||
 621                 (out + in > VIRTNET_SEND_COMMAND_SG_MAX));
 622
 623         out++; /* Add header */
 624         in++; /* Add return status */
 625
 626         ctrl.class = class;
 627         ctrl.cmd = cmd;
 628
 629         sg_init_table(sg, out + in);
 630
 631         sg_set_buf(&sg[0], &ctrl, sizeof(ctrl));
 632         for_each_sg(data, s, out + in - 2, i)
 633                 sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
 634         sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
 635
 636         BUG_ON(vi->cvq->vq_ops->add_buf(vi->cvq, sg, out, in, vi) < 0);
 637
 638         vi->cvq->vq_ops->kick(vi->cvq);
 639
 640         /*
 641          * Spin for a response, the kick causes an ioport write, trapping
 642          * into the hypervisor, so the request should be handled immediately.
 643          */
 644         while (!vi->cvq->vq_ops->get_buf(vi->cvq, &tmp))
 645                 cpu_relax();
 646
 647         return status == VIRTIO_NET_OK;
 648 }
 649
 650 static int virtnet_close(struct net_device *dev)
 651 {
 652         struct virtnet_info *vi = netdev_priv(dev);
 653
 654         napi_disable(&vi->napi);
 655
 656         return 0;
 657 }
 658
 659 static int virtnet_set_tx_csum(struct net_device *dev, u32 data)
 660 {
 661         struct virtnet_info *vi = netdev_priv(dev);
 662         struct virtio_device *vdev = vi->vdev;
 663
 664         if (data && !virtio_has_feature(vdev, VIRTIO_NET_F_CSUM))
 665                 return -ENOSYS;
 666
 667         return ethtool_op_set_tx_hw_csum(dev, data);
 668 }
 669
 670 static void virtnet_set_rx_mode(struct net_device *dev)
 671 {
 672         struct virtnet_info *vi = netdev_priv(dev);
 673         struct scatterlist sg[2];
 674         u8 promisc, allmulti;
 675         struct virtio_net_ctrl_mac *mac_data;
 676         struct dev_addr_list *addr;
 677         struct netdev_hw_addr *ha;
 678         void *buf;
 679         int i;
 680
 681         /* We can't dynamicaly set ndo_set_rx_mode, so return gracefully */
 682         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
 683                 return;
 684
 685         promisc = ((dev->flags & IFF_PROMISC) != 0);
 686         allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
 687
 688         sg_init_one(sg, &promisc, sizeof(promisc));
 689
 690         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 691                                   VIRTIO_NET_CTRL_RX_PROMISC,
 692                                   sg, 1, 0))
 693                 dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
 694                          promisc ? "en" : "dis");
 695
 696         sg_init_one(sg, &allmulti, sizeof(allmulti));
 697
 698         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 699                                   VIRTIO_NET_CTRL_RX_ALLMULTI,
 700                                   sg, 1, 0))
 701                 dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
 702                          allmulti ? "en" : "dis");
 703
 704         /* MAC filter - use one buffer for both lists */
 705         mac_data = buf = kzalloc(((dev->uc.count + dev->mc_count) * ETH_ALEN) +
 706                                  (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
 707         if (!buf) {
 708                 dev_warn(&dev->dev, "No memory for MAC address buffer\n");
 709                 return;
 710         }
 711
 712         sg_init_table(sg, 2);
 713
 714         /* Store the unicast list and count in the front of the buffer */
 715         mac_data->entries = dev->uc.count;
 716         i = 0;
 717         list_for_each_entry(ha, &dev->uc.list, list)
 718                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 719
 720         sg_set_buf(&sg[0], mac_data,
 721                    sizeof(mac_data->entries) + (dev->uc.count * ETH_ALEN));
 722
 723         /* multicast list and count fill the end */
 724         mac_data = (void *)&mac_data->macs[dev->uc.count][0];
 725
 726         mac_data->entries = dev->mc_count;
 727         addr = dev->mc_list;
 728         for (i = 0; i < dev->mc_count; i++, addr = addr->next)
 729                 memcpy(&mac_data->macs[i][0], addr->da_addr, ETH_ALEN);
 730
 731         sg_set_buf(&sg[1], mac_data,
 732                    sizeof(mac_data->entries) + (dev->mc_count * ETH_ALEN));
 733
 734         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
 735                                   VIRTIO_NET_CTRL_MAC_TABLE_SET,
 736                                   sg, 2, 0))
 737                 dev_warn(&dev->dev, "Failed to set MAC fitler table.\n");
 738
 739         kfree(buf);
 740 }
 741
 742 static void virtnet_vlan_rx_add_vid(struct net_device *dev, u16 vid)
 743 {
 744         struct virtnet_info *vi = netdev_priv(dev);
 745         struct scatterlist sg;
 746
 747         sg_init_one(&sg, &vid, sizeof(vid));
 748
 749         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 750                                   VIRTIO_NET_CTRL_VLAN_ADD, &sg, 1, 0))
 751                 dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
 752 }
 753
 754 static void virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
 755 {
 756         struct virtnet_info *vi = netdev_priv(dev);
 757         struct scatterlist sg;
 758
 759         sg_init_one(&sg, &vid, sizeof(vid));
 760
 761         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 762                                   VIRTIO_NET_CTRL_VLAN_DEL, &sg, 1, 0))
 763                 dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
 764 }
 765
 766 static const struct ethtool_ops virtnet_ethtool_ops = {
 767         .set_tx_csum = virtnet_set_tx_csum,
 768         .set_sg = ethtool_op_set_sg,
 769         .set_tso = ethtool_op_set_tso,
 770         .set_ufo = ethtool_op_set_ufo,
 771         .get_link = ethtool_op_get_link,
 772 };
 773
 774 #define MIN_MTU 68
 775 #define MAX_MTU 65535
 776
 777 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
 778 {
 779         if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
 780                 return -EINVAL;
 781         dev->mtu = new_mtu;
 782         return 0;
 783 }
 784
 785 static const struct net_device_ops virtnet_netdev = {
 786         .ndo_open            = virtnet_open,
 787         .ndo_stop            = virtnet_close,
 788         .ndo_start_xmit      = start_xmit,
 789         .ndo_validate_addr   = eth_validate_addr,
 790         .ndo_set_mac_address = virtnet_set_mac_address,
 791         .ndo_set_rx_mode     = virtnet_set_rx_mode,
 792         .ndo_change_mtu      = virtnet_change_mtu,
 793         .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
 794         .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
 795 #ifdef CONFIG_NET_POLL_CONTROLLER
 796         .ndo_poll_controller = virtnet_netpoll,
 797 #endif
 798 };
 799
 800 static void virtnet_update_status(struct virtnet_info *vi)
 801 {
 802         u16 v;
 803
 804         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS))
 805                 return;
 806
 807         vi->vdev->config->get(vi->vdev,
 808                               offsetof(struct virtio_net_config, status),
 809                               &v, sizeof(v));
 810
 811         /* Ignore unknown (future) status bits */
 812         v &= VIRTIO_NET_S_LINK_UP;
 813
 814         if (vi->status == v)
 815                 return;
 816
 817         vi->status = v;
 818
 819         if (vi->status & VIRTIO_NET_S_LINK_UP) {
 820                 netif_carrier_on(vi->dev);
 821                 netif_wake_queue(vi->dev);
 822         } else {
 823                 netif_carrier_off(vi->dev);
 824                 netif_stop_queue(vi->dev);
 825         }
 826 }
 827
 828 static void virtnet_config_changed(struct virtio_device *vdev)
 829 {
 830         struct virtnet_info *vi = vdev->priv;
 831
 832         virtnet_update_status(vi);
 833 }
 834
 835 static int virtnet_probe(struct virtio_device *vdev)
 836 {
 837         int err;
 838         struct net_device *dev;
 839         struct virtnet_info *vi;
 840         struct virtqueue *vqs[3];
 841         vq_callback_t *callbacks[] = { skb_recv_done, skb_xmit_done, NULL};
 842         const char *names[] = { "input", "output", "control" };
 843         int nvqs;
 844
 845         /* Allocate ourselves a network device with room for our info */
 846         dev = alloc_etherdev(sizeof(struct virtnet_info));
 847         if (!dev)
 848                 return -ENOMEM;
 849
 850         /* Set up network device as normal. */
 851         dev->netdev_ops = &virtnet_netdev;
 852         dev->features = NETIF_F_HIGHDMA;
 853         SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
 854         SET_NETDEV_DEV(dev, &vdev->dev);
 855
 856         /* Do we support "hardware" checksums? */
 857         if (csum && virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
 858                 /* This opens up the world of extra features. */
 859                 dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
 860                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
 861                         dev->features |= NETIF_F_TSO | NETIF_F_UFO
 862                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
 863                 }
 864                 /* Individual feature bits: what can host handle? */
 865                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
 866                         dev->features |= NETIF_F_TSO;
 867                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
 868                         dev->features |= NETIF_F_TSO6;
 869                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
 870                         dev->features |= NETIF_F_TSO_ECN;
 871                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
 872                         dev->features |= NETIF_F_UFO;
 873         }
 874
 875         /* Configuration may specify what MAC to use.  Otherwise random. */
 876         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
 877                 vdev->config->get(vdev,
 878                                   offsetof(struct virtio_net_config, mac),
 879                                   dev->dev_addr, dev->addr_len);
 880         } else
 881                 random_ether_addr(dev->dev_addr);
 882
 883         /* Set up our device-specific information */
 884         vi = netdev_priv(dev);
 885         netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
 886         vi->dev = dev;
 887         vi->vdev = vdev;
 888         vdev->priv = vi;
 889         vi->pages = NULL;
 890         INIT_DELAYED_WORK(&vi->refill, refill_work);
 891
 892         /* If we can receive ANY GSO packets, we must allocate large ones. */
 893         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4)
 894             || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6)
 895             || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
 896                 vi->big_packets = true;
 897
 898         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
 899                 vi->mergeable_rx_bufs = true;
 900
 901         /* We expect two virtqueues, receive then send,
 902          * and optionally control. */
 903         nvqs = virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ? 3 : 2;
 904
 905         err = vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names);
 906         if (err)
 907                 goto free;
 908
 909         vi->rvq = vqs[0];
 910         vi->svq = vqs[1];
 911
 912         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
 913                 vi->cvq = vqs[2];
 914
 915                 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
 916                         dev->features |= NETIF_F_HW_VLAN_FILTER;
 917         }
 918
 919         /* Initialize our empty receive and send queues. */
 920         skb_queue_head_init(&vi->recv);
 921         skb_queue_head_init(&vi->send);
 922
 923         err = register_netdev(dev);
 924         if (err) {
 925                 pr_debug("virtio_net: registering device failed\n");
 926                 goto free_vqs;
 927         }
 928
 929         /* Last of all, set up some receive buffers. */
 930         try_fill_recv(vi, GFP_KERNEL);
 931
 932         /* If we didn't even get one input buffer, we're useless. */
 933         if (vi->num == 0) {
 934                 err = -ENOMEM;
 935                 goto unregister;
 936         }
 937
 938         vi->status = VIRTIO_NET_S_LINK_UP;
 939         virtnet_update_status(vi);
 940         netif_carrier_on(dev);
 941
 942         pr_debug("virtnet: registered device %s\n", dev->name);
 943         return 0;
 944
 945 unregister:
 946         unregister_netdev(dev);
 947         cancel_delayed_work_sync(&vi->refill);
 948 free_vqs:
 949         vdev->config->del_vqs(vdev);
 950 free:
 951         free_netdev(dev);
 952         return err;
 953 }
 954
 955 static void __devexit virtnet_remove(struct virtio_device *vdev)
 956 {
 957         struct virtnet_info *vi = vdev->priv;
 958         struct sk_buff *skb;
 959
 960         /* Stop all the virtqueues. */
 961         vdev->config->reset(vdev);
 962
 963         /* Free our skbs in send and recv queues, if any. */
 964         while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
 965                 kfree_skb(skb);
 966                 vi->num--;
 967         }
 968         __skb_queue_purge(&vi->send);
 969
 970         BUG_ON(vi->num != 0);
 971
 972         unregister_netdev(vi->dev);
 973         cancel_delayed_work_sync(&vi->refill);
 974
 975         vdev->config->del_vqs(vi->vdev);
 976
 977         while (vi->pages)
 978                 __free_pages(get_a_page(vi, GFP_KERNEL), 0);
 979
 980         free_netdev(vi->dev);
 981 }
 982
 983 static struct virtio_device_id id_table[] = {
 984         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
 985         { 0 },
 986 };
 987
 988 static unsigned int features[] = {
 989         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
 990         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
 991         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
 992         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
 993         VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
 994         VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
 995         VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
 996 };
 997
 998 static struct virtio_driver virtio_net_driver = {
 999         .feature_table = features,
1000         .feature_table_size = ARRAY_SIZE(features),
1001         .driver.name =  KBUILD_MODNAME,
1002         .driver.owner = THIS_MODULE,
1003         .id_table =     id_table,
1004         .probe =        virtnet_probe,
1005         .remove =       __devexit_p(virtnet_remove),
1006         .config_changed = virtnet_config_changed,
1007 };
1008
1009 static int __init init(void)
1010 {
1011         return register_virtio_driver(&virtio_net_driver);
1012 }
1013
1014 static void __exit fini(void)
1015 {
1016         unregister_virtio_driver(&virtio_net_driver);
1017 }
1018 module_init(init);
1019 module_exit(fini);
1020
1021 MODULE_DEVICE_TABLE(virtio, id_table);
1022 MODULE_DESCRIPTION("Virtio network driver");
1023 MODULE_LICENSE("GPL");