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         struct virtio_device *vdev;
  44         struct virtqueue *rvq, *svq, *cvq;
  45         struct net_device *dev;
  46         struct napi_struct napi;
  47         unsigned int status;
  48
  49         /* Number of input buffers, and max we've ever had. */
  50         unsigned int num, max;
  51
  52         /* I like... big packets and I cannot lie! */
  53         bool big_packets;
  54
  55         /* Host will merge rx buffers for big packets (shake it! shake it!) */
  56         bool mergeable_rx_bufs;
  57
  58         /* Work struct for refilling if we run low on memory. */
  59         struct delayed_work refill;
  60
  61         /* Chain pages by the private ptr. */
  62         struct page *pages;
  63
  64         /* fragments + linear part + virtio header */
  65         struct scatterlist rx_sg[MAX_SKB_FRAGS + 2];
  66         struct scatterlist tx_sg[MAX_SKB_FRAGS + 2];
  67 };
  68
  69 struct skb_vnet_hdr {
  70         union {
  71                 struct virtio_net_hdr hdr;
  72                 struct virtio_net_hdr_mrg_rxbuf mhdr;
  73         };
  74         unsigned int num_sg;
  75 };
  76
  77 struct padded_vnet_hdr {
  78         struct virtio_net_hdr hdr;
  79         /*
  80          * virtio_net_hdr should be in a separated sg buffer because of a
  81          * QEMU bug, and data sg buffer shares same page with this header sg.
  82          * This padding makes next sg 16 byte aligned after virtio_net_hdr.
  83          */
  84         char padding[6];
  85 };
  86
  87 static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
  88 {
  89         return (struct skb_vnet_hdr *)skb->cb;
  90 }
  91
  92 /*
  93  * private is used to chain pages for big packets, put the whole
  94  * most recent used list in the beginning for reuse
  95  */
  96 static void give_pages(struct virtnet_info *vi, struct page *page)
  97 {
  98         struct page *end;
  99
 100         /* Find end of list, sew whole thing into vi->pages. */
 101         for (end = page; end->private; end = (struct page *)end->private);
 102         end->private = (unsigned long)vi->pages;
 103         vi->pages = page;
 104 }
 105
 106 static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
 107 {
 108         struct page *p = vi->pages;
 109
 110         if (p) {
 111                 vi->pages = (struct page *)p->private;
 112                 /* clear private here, it is used to chain pages */
 113                 p->private = 0;
 114         } else
 115                 p = alloc_page(gfp_mask);
 116         return p;
 117 }
 118
 119 static void skb_xmit_done(struct virtqueue *svq)
 120 {
 121         struct virtnet_info *vi = svq->vdev->priv;
 122
 123         /* Suppress further interrupts. */
 124         svq->vq_ops->disable_cb(svq);
 125
 126         /* We were probably waiting for more output buffers. */
 127         netif_wake_queue(vi->dev);
 128 }
 129
 130 static void set_skb_frag(struct sk_buff *skb, struct page *page,
 131                          unsigned int offset, unsigned int *len)
 132 {
 133         int i = skb_shinfo(skb)->nr_frags;
 134         skb_frag_t *f;
 135
 136         f = &skb_shinfo(skb)->frags[i];
 137         f->size = min((unsigned)PAGE_SIZE - offset, *len);
 138         f->page_offset = offset;
 139         f->page = page;
 140
 141         skb->data_len += f->size;
 142         skb->len += f->size;
 143         skb_shinfo(skb)->nr_frags++;
 144         *len -= f->size;
 145 }
 146
 147 static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 148                                    struct page *page, unsigned int len)
 149 {
 150         struct sk_buff *skb;
 151         struct skb_vnet_hdr *hdr;
 152         unsigned int copy, hdr_len, offset;
 153         char *p;
 154
 155         p = page_address(page);
 156
 157         /* copy small packet so we can reuse these pages for small data */
 158         skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
 159         if (unlikely(!skb))
 160                 return NULL;
 161
 162         hdr = skb_vnet_hdr(skb);
 163
 164         if (vi->mergeable_rx_bufs) {
 165                 hdr_len = sizeof hdr->mhdr;
 166                 offset = hdr_len;
 167         } else {
 168                 hdr_len = sizeof hdr->hdr;
 169                 offset = sizeof(struct padded_vnet_hdr);
 170         }
 171
 172         memcpy(hdr, p, hdr_len);
 173
 174         len -= hdr_len;
 175         p += offset;
 176
 177         copy = len;
 178         if (copy > skb_tailroom(skb))
 179                 copy = skb_tailroom(skb);
 180         memcpy(skb_put(skb, copy), p, copy);
 181
 182         len -= copy;
 183         offset += copy;
 184
 185         while (len) {
 186                 set_skb_frag(skb, page, offset, &len);
 187                 page = (struct page *)page->private;
 188                 offset = 0;
 189         }
 190
 191         if (page)
 192                 give_pages(vi, page);
 193
 194         return skb;
 195 }
 196
 197 static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb)
 198 {
 199         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 200         struct page *page;
 201         int num_buf, i, len;
 202
 203         num_buf = hdr->mhdr.num_buffers;
 204         while (--num_buf) {
 205                 i = skb_shinfo(skb)->nr_frags;
 206                 if (i >= MAX_SKB_FRAGS) {
 207                         pr_debug("%s: packet too long\n", skb->dev->name);
 208                         skb->dev->stats.rx_length_errors++;
 209                         return -EINVAL;
 210                 }
 211
 212                 page = vi->rvq->vq_ops->get_buf(vi->rvq, &len);
 213                 if (!page) {
 214                         pr_debug("%s: rx error: %d buffers missing\n",
 215                                  skb->dev->name, hdr->mhdr.num_buffers);
 216                         skb->dev->stats.rx_length_errors++;
 217                         return -EINVAL;
 218                 }
 219                 if (len > PAGE_SIZE)
 220                         len = PAGE_SIZE;
 221
 222                 set_skb_frag(skb, page, 0, &len);
 223
 224                 --vi->num;
 225         }
 226         return 0;
 227 }
 228
 229 static void receive_buf(struct net_device *dev, void *buf, unsigned int len)
 230 {
 231         struct virtnet_info *vi = netdev_priv(dev);
 232         struct sk_buff *skb;
 233         struct page *page;
 234         struct skb_vnet_hdr *hdr;
 235
 236         if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
 237                 pr_debug("%s: short packet %i\n", dev->name, len);
 238                 dev->stats.rx_length_errors++;
 239                 if (vi->mergeable_rx_bufs || vi->big_packets)
 240                         give_pages(vi, buf);
 241                 else
 242                         dev_kfree_skb(buf);
 243                 return;
 244         }
 245
 246         if (!vi->mergeable_rx_bufs && !vi->big_packets) {
 247                 skb = buf;
 248                 len -= sizeof(struct virtio_net_hdr);
 249                 skb_trim(skb, len);
 250         } else {
 251                 page = buf;
 252                 skb = page_to_skb(vi, page, len);
 253                 if (unlikely(!skb)) {
 254                         dev->stats.rx_dropped++;
 255                         give_pages(vi, page);
 256                         return;
 257                 }
 258                 if (vi->mergeable_rx_bufs)
 259                         if (receive_mergeable(vi, skb)) {
 260                                 dev_kfree_skb(skb);
 261                                 return;
 262                         }
 263         }
 264
 265         hdr = skb_vnet_hdr(skb);
 266         skb->truesize += skb->data_len;
 267         dev->stats.rx_bytes += skb->len;
 268         dev->stats.rx_packets++;
 269
 270         if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 271                 pr_debug("Needs csum!\n");
 272                 if (!skb_partial_csum_set(skb,
 273                                           hdr->hdr.csum_start,
 274                                           hdr->hdr.csum_offset))
 275                         goto frame_err;
 276         }
 277
 278         skb->protocol = eth_type_trans(skb, dev);
 279         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
 280                  ntohs(skb->protocol), skb->len, skb->pkt_type);
 281
 282         if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 283                 pr_debug("GSO!\n");
 284                 switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 285                 case VIRTIO_NET_HDR_GSO_TCPV4:
 286                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 287                         break;
 288                 case VIRTIO_NET_HDR_GSO_UDP:
 289                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 290                         break;
 291                 case VIRTIO_NET_HDR_GSO_TCPV6:
 292                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 293                         break;
 294                 default:
 295                         if (net_ratelimit())
 296                                 printk(KERN_WARNING "%s: bad gso type %u.\n",
 297                                        dev->name, hdr->hdr.gso_type);
 298                         goto frame_err;
 299                 }
 300
 301                 if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 302                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 303
 304                 skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
 305                 if (skb_shinfo(skb)->gso_size == 0) {
 306                         if (net_ratelimit())
 307                                 printk(KERN_WARNING "%s: zero gso size.\n",
 308                                        dev->name);
 309                         goto frame_err;
 310                 }
 311
 312                 /* Header must be checked, and gso_segs computed. */
 313                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 314                 skb_shinfo(skb)->gso_segs = 0;
 315         }
 316
 317         netif_receive_skb(skb);
 318         return;
 319
 320 frame_err:
 321         dev->stats.rx_frame_errors++;
 322         dev_kfree_skb(skb);
 323 }
 324
 325 static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp)
 326 {
 327         struct sk_buff *skb;
 328         struct skb_vnet_hdr *hdr;
 329         int err;
 330
 331         skb = netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN);
 332         if (unlikely(!skb))
 333                 return -ENOMEM;
 334
 335         skb_put(skb, MAX_PACKET_LEN);
 336
 337         hdr = skb_vnet_hdr(skb);
 338         sg_set_buf(vi->rx_sg, &hdr->hdr, sizeof hdr->hdr);
 339
 340         skb_to_sgvec(skb, vi->rx_sg + 1, 0, skb->len);
 341
 342         err = vi->rvq->vq_ops->add_buf(vi->rvq, vi->rx_sg, 0, 2, skb);
 343         if (err < 0)
 344                 dev_kfree_skb(skb);
 345
 346         return err;
 347 }
 348
 349 static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp)
 350 {
 351         struct page *first, *list = NULL;
 352         char *p;
 353         int i, err, offset;
 354
 355         /* page in vi->rx_sg[MAX_SKB_FRAGS + 1] is list tail */
 356         for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
 357                 first = get_a_page(vi, gfp);
 358                 if (!first) {
 359                         if (list)
 360                                 give_pages(vi, list);
 361                         return -ENOMEM;
 362                 }
 363                 sg_set_buf(&vi->rx_sg[i], page_address(first), PAGE_SIZE);
 364
 365                 /* chain new page in list head to match sg */
 366                 first->private = (unsigned long)list;
 367                 list = first;
 368         }
 369
 370         first = get_a_page(vi, gfp);
 371         if (!first) {
 372                 give_pages(vi, list);
 373                 return -ENOMEM;
 374         }
 375         p = page_address(first);
 376
 377         /* vi->rx_sg[0], vi->rx_sg[1] share the same page */
 378         /* a separated vi->rx_sg[0] for virtio_net_hdr only due to QEMU bug */
 379         sg_set_buf(&vi->rx_sg[0], p, sizeof(struct virtio_net_hdr));
 380
 381         /* vi->rx_sg[1] for data packet, from offset */
 382         offset = sizeof(struct padded_vnet_hdr);
 383         sg_set_buf(&vi->rx_sg[1], p + offset, PAGE_SIZE - offset);
 384
 385         /* chain first in list head */
 386         first->private = (unsigned long)list;
 387         err = vi->rvq->vq_ops->add_buf(vi->rvq, vi->rx_sg, 0, MAX_SKB_FRAGS + 2,
 388                                        first);
 389         if (err < 0)
 390                 give_pages(vi, first);
 391
 392         return err;
 393 }
 394
 395 static int add_recvbuf_mergeable(struct virtnet_info *vi, gfp_t gfp)
 396 {
 397         struct page *page;
 398         int err;
 399
 400         page = get_a_page(vi, gfp);
 401         if (!page)
 402                 return -ENOMEM;
 403
 404         sg_init_one(vi->rx_sg, page_address(page), PAGE_SIZE);
 405
 406         err = vi->rvq->vq_ops->add_buf(vi->rvq, vi->rx_sg, 0, 1, page);
 407         if (err < 0)
 408                 give_pages(vi, page);
 409
 410         return err;
 411 }
 412
 413 /* Returns false if we couldn't fill entirely (OOM). */
 414 static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
 415 {
 416         int err;
 417         bool oom = false;
 418
 419         do {
 420                 if (vi->mergeable_rx_bufs)
 421                         err = add_recvbuf_mergeable(vi, gfp);
 422                 else if (vi->big_packets)
 423                         err = add_recvbuf_big(vi, gfp);
 424                 else
 425                         err = add_recvbuf_small(vi, gfp);
 426
 427                 if (err < 0) {
 428                         oom = true;
 429                         break;
 430                 }
 431                 ++vi->num;
 432         } while (err > 0);
 433         if (unlikely(vi->num > vi->max))
 434                 vi->max = vi->num;
 435         vi->rvq->vq_ops->kick(vi->rvq);
 436         return !oom;
 437 }
 438
 439 static void skb_recv_done(struct virtqueue *rvq)
 440 {
 441         struct virtnet_info *vi = rvq->vdev->priv;
 442         /* Schedule NAPI, Suppress further interrupts if successful. */
 443         if (napi_schedule_prep(&vi->napi)) {
 444                 rvq->vq_ops->disable_cb(rvq);
 445                 __napi_schedule(&vi->napi);
 446         }
 447 }
 448
 449 static void refill_work(struct work_struct *work)
 450 {
 451         struct virtnet_info *vi;
 452         bool still_empty;
 453
 454         vi = container_of(work, struct virtnet_info, refill.work);
 455         napi_disable(&vi->napi);
 456         still_empty = !try_fill_recv(vi, GFP_KERNEL);
 457         napi_enable(&vi->napi);
 458
 459         /* In theory, this can happen: if we don't get any buffers in
 460          * we will *never* try to fill again. */
 461         if (still_empty)
 462                 schedule_delayed_work(&vi->refill, HZ/2);
 463 }
 464
 465 static int virtnet_poll(struct napi_struct *napi, int budget)
 466 {
 467         struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
 468         void *buf;
 469         unsigned int len, received = 0;
 470
 471 again:
 472         while (received < budget &&
 473                (buf = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
 474                 receive_buf(vi->dev, buf, len);
 475                 --vi->num;
 476                 received++;
 477         }
 478
 479         if (vi->num < vi->max / 2) {
 480                 if (!try_fill_recv(vi, GFP_ATOMIC))
 481                         schedule_delayed_work(&vi->refill, 0);
 482         }
 483
 484         /* Out of packets? */
 485         if (received < budget) {
 486                 napi_complete(napi);
 487                 if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq)) &&
 488                     napi_schedule_prep(napi)) {
 489                         vi->rvq->vq_ops->disable_cb(vi->rvq);
 490                         __napi_schedule(napi);
 491                         goto again;
 492                 }
 493         }
 494
 495         return received;
 496 }
 497
 498 static unsigned int free_old_xmit_skbs(struct virtnet_info *vi)
 499 {
 500         struct sk_buff *skb;
 501         unsigned int len, tot_sgs = 0;
 502
 503         while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
 504                 pr_debug("Sent skb %p\n", skb);
 505                 vi->dev->stats.tx_bytes += skb->len;
 506                 vi->dev->stats.tx_packets++;
 507                 tot_sgs += skb_vnet_hdr(skb)->num_sg;
 508                 dev_kfree_skb_any(skb);
 509         }
 510         return tot_sgs;
 511 }
 512
 513 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
 514 {
 515         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 516         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 517
 518         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
 519
 520         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 521                 hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 522                 hdr->hdr.csum_start = skb->csum_start - skb_headroom(skb);
 523                 hdr->hdr.csum_offset = skb->csum_offset;
 524         } else {
 525                 hdr->hdr.flags = 0;
 526                 hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
 527         }
 528
 529         if (skb_is_gso(skb)) {
 530                 hdr->hdr.hdr_len = skb_headlen(skb);
 531                 hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
 532                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 533                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 534                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 535                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 536                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 537                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 538                 else
 539                         BUG();
 540                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
 541                         hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 542         } else {
 543                 hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 544                 hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
 545         }
 546
 547         hdr->mhdr.num_buffers = 0;
 548
 549         /* Encode metadata header at front. */
 550         if (vi->mergeable_rx_bufs)
 551                 sg_set_buf(vi->tx_sg, &hdr->mhdr, sizeof hdr->mhdr);
 552         else
 553                 sg_set_buf(vi->tx_sg, &hdr->hdr, sizeof hdr->hdr);
 554
 555         hdr->num_sg = skb_to_sgvec(skb, vi->tx_sg + 1, 0, skb->len) + 1;
 556         return vi->svq->vq_ops->add_buf(vi->svq, vi->tx_sg, hdr->num_sg,
 557                                         0, skb);
 558 }
 559
 560 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 561 {
 562         struct virtnet_info *vi = netdev_priv(dev);
 563         int capacity;
 564
 565 again:
 566         /* Free up any pending old buffers before queueing new ones. */
 567         free_old_xmit_skbs(vi);
 568
 569         /* Try to transmit */
 570         capacity = xmit_skb(vi, skb);
 571
 572         /* This can happen with OOM and indirect buffers. */
 573         if (unlikely(capacity < 0)) {
 574                 netif_stop_queue(dev);
 575                 dev_warn(&dev->dev, "Unexpected full queue\n");
 576                 if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
 577                         vi->svq->vq_ops->disable_cb(vi->svq);
 578                         netif_start_queue(dev);
 579                         goto again;
 580                 }
 581                 return NETDEV_TX_BUSY;
 582         }
 583         vi->svq->vq_ops->kick(vi->svq);
 584
 585         /* Don't wait up for transmitted skbs to be freed. */
 586         skb_orphan(skb);
 587         nf_reset(skb);
 588
 589         /* Apparently nice girls don't return TX_BUSY; stop the queue
 590          * before it gets out of hand.  Naturally, this wastes entries. */
 591         if (capacity < 2+MAX_SKB_FRAGS) {
 592                 netif_stop_queue(dev);
 593                 if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
 594                         /* More just got used, free them then recheck. */
 595                         capacity += free_old_xmit_skbs(vi);
 596                         if (capacity >= 2+MAX_SKB_FRAGS) {
 597                                 netif_start_queue(dev);
 598                                 vi->svq->vq_ops->disable_cb(vi->svq);
 599                         }
 600                 }
 601         }
 602
 603         return NETDEV_TX_OK;
 604 }
 605
 606 static int virtnet_set_mac_address(struct net_device *dev, void *p)
 607 {
 608         struct virtnet_info *vi = netdev_priv(dev);
 609         struct virtio_device *vdev = vi->vdev;
 610         int ret;
 611
 612         ret = eth_mac_addr(dev, p);
 613         if (ret)
 614                 return ret;
 615
 616         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
 617                 vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
 618                                   dev->dev_addr, dev->addr_len);
 619
 620         return 0;
 621 }
 622
 623 #ifdef CONFIG_NET_POLL_CONTROLLER
 624 static void virtnet_netpoll(struct net_device *dev)
 625 {
 626         struct virtnet_info *vi = netdev_priv(dev);
 627
 628         napi_schedule(&vi->napi);
 629 }
 630 #endif
 631
 632 static int virtnet_open(struct net_device *dev)
 633 {
 634         struct virtnet_info *vi = netdev_priv(dev);
 635
 636         napi_enable(&vi->napi);
 637
 638         /* If all buffers were filled by other side before we napi_enabled, we
 639          * won't get another interrupt, so process any outstanding packets
 640          * now.  virtnet_poll wants re-enable the queue, so we disable here.
 641          * We synchronize against interrupts via NAPI_STATE_SCHED */
 642         if (napi_schedule_prep(&vi->napi)) {
 643                 vi->rvq->vq_ops->disable_cb(vi->rvq);
 644                 __napi_schedule(&vi->napi);
 645         }
 646         return 0;
 647 }
 648
 649 /*
 650  * Send command via the control virtqueue and check status.  Commands
 651  * supported by the hypervisor, as indicated by feature bits, should
 652  * never fail unless improperly formated.
 653  */
 654 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
 655                                  struct scatterlist *data, int out, int in)
 656 {
 657         struct scatterlist *s, sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
 658         struct virtio_net_ctrl_hdr ctrl;
 659         virtio_net_ctrl_ack status = ~0;
 660         unsigned int tmp;
 661         int i;
 662
 663         /* Caller should know better */
 664         BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ||
 665                 (out + in > VIRTNET_SEND_COMMAND_SG_MAX));
 666
 667         out++; /* Add header */
 668         in++; /* Add return status */
 669
 670         ctrl.class = class;
 671         ctrl.cmd = cmd;
 672
 673         sg_init_table(sg, out + in);
 674
 675         sg_set_buf(&sg[0], &ctrl, sizeof(ctrl));
 676         for_each_sg(data, s, out + in - 2, i)
 677                 sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
 678         sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
 679
 680         BUG_ON(vi->cvq->vq_ops->add_buf(vi->cvq, sg, out, in, vi) < 0);
 681
 682         vi->cvq->vq_ops->kick(vi->cvq);
 683
 684         /*
 685          * Spin for a response, the kick causes an ioport write, trapping
 686          * into the hypervisor, so the request should be handled immediately.
 687          */
 688         while (!vi->cvq->vq_ops->get_buf(vi->cvq, &tmp))
 689                 cpu_relax();
 690
 691         return status == VIRTIO_NET_OK;
 692 }
 693
 694 static int virtnet_close(struct net_device *dev)
 695 {
 696         struct virtnet_info *vi = netdev_priv(dev);
 697
 698         napi_disable(&vi->napi);
 699
 700         return 0;
 701 }
 702
 703 static int virtnet_set_tx_csum(struct net_device *dev, u32 data)
 704 {
 705         struct virtnet_info *vi = netdev_priv(dev);
 706         struct virtio_device *vdev = vi->vdev;
 707
 708         if (data && !virtio_has_feature(vdev, VIRTIO_NET_F_CSUM))
 709                 return -ENOSYS;
 710
 711         return ethtool_op_set_tx_hw_csum(dev, data);
 712 }
 713
 714 static void virtnet_set_rx_mode(struct net_device *dev)
 715 {
 716         struct virtnet_info *vi = netdev_priv(dev);
 717         struct scatterlist sg[2];
 718         u8 promisc, allmulti;
 719         struct virtio_net_ctrl_mac *mac_data;
 720         struct netdev_hw_addr *ha;
 721         int uc_count;
 722         int mc_count;
 723         void *buf;
 724         int i;
 725
 726         /* We can't dynamicaly set ndo_set_rx_mode, so return gracefully */
 727         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
 728                 return;
 729
 730         promisc = ((dev->flags & IFF_PROMISC) != 0);
 731         allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
 732
 733         sg_init_one(sg, &promisc, sizeof(promisc));
 734
 735         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 736                                   VIRTIO_NET_CTRL_RX_PROMISC,
 737                                   sg, 1, 0))
 738                 dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
 739                          promisc ? "en" : "dis");
 740
 741         sg_init_one(sg, &allmulti, sizeof(allmulti));
 742
 743         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 744                                   VIRTIO_NET_CTRL_RX_ALLMULTI,
 745                                   sg, 1, 0))
 746                 dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
 747                          allmulti ? "en" : "dis");
 748
 749         uc_count = netdev_uc_count(dev);
 750         mc_count = netdev_mc_count(dev);
 751         /* MAC filter - use one buffer for both lists */
 752         buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
 753                       (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
 754         mac_data = buf;
 755         if (!buf) {
 756                 dev_warn(&dev->dev, "No memory for MAC address buffer\n");
 757                 return;
 758         }
 759
 760         sg_init_table(sg, 2);
 761
 762         /* Store the unicast list and count in the front of the buffer */
 763         mac_data->entries = uc_count;
 764         i = 0;
 765         netdev_for_each_uc_addr(ha, dev)
 766                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 767
 768         sg_set_buf(&sg[0], mac_data,
 769                    sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
 770
 771         /* multicast list and count fill the end */
 772         mac_data = (void *)&mac_data->macs[uc_count][0];
 773
 774         mac_data->entries = mc_count;
 775         i = 0;
 776         netdev_for_each_mc_addr(ha, dev)
 777                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 778
 779         sg_set_buf(&sg[1], mac_data,
 780                    sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
 781
 782         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
 783                                   VIRTIO_NET_CTRL_MAC_TABLE_SET,
 784                                   sg, 2, 0))
 785                 dev_warn(&dev->dev, "Failed to set MAC fitler table.\n");
 786
 787         kfree(buf);
 788 }
 789
 790 static void virtnet_vlan_rx_add_vid(struct net_device *dev, u16 vid)
 791 {
 792         struct virtnet_info *vi = netdev_priv(dev);
 793         struct scatterlist sg;
 794
 795         sg_init_one(&sg, &vid, sizeof(vid));
 796
 797         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 798                                   VIRTIO_NET_CTRL_VLAN_ADD, &sg, 1, 0))
 799                 dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
 800 }
 801
 802 static void virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
 803 {
 804         struct virtnet_info *vi = netdev_priv(dev);
 805         struct scatterlist sg;
 806
 807         sg_init_one(&sg, &vid, sizeof(vid));
 808
 809         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 810                                   VIRTIO_NET_CTRL_VLAN_DEL, &sg, 1, 0))
 811                 dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
 812 }
 813
 814 static const struct ethtool_ops virtnet_ethtool_ops = {
 815         .set_tx_csum = virtnet_set_tx_csum,
 816         .set_sg = ethtool_op_set_sg,
 817         .set_tso = ethtool_op_set_tso,
 818         .set_ufo = ethtool_op_set_ufo,
 819         .get_link = ethtool_op_get_link,
 820 };
 821
 822 #define MIN_MTU 68
 823 #define MAX_MTU 65535
 824
 825 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
 826 {
 827         if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
 828                 return -EINVAL;
 829         dev->mtu = new_mtu;
 830         return 0;
 831 }
 832
 833 static const struct net_device_ops virtnet_netdev = {
 834         .ndo_open            = virtnet_open,
 835         .ndo_stop            = virtnet_close,
 836         .ndo_start_xmit      = start_xmit,
 837         .ndo_validate_addr   = eth_validate_addr,
 838         .ndo_set_mac_address = virtnet_set_mac_address,
 839         .ndo_set_rx_mode     = virtnet_set_rx_mode,
 840         .ndo_change_mtu      = virtnet_change_mtu,
 841         .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
 842         .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
 843 #ifdef CONFIG_NET_POLL_CONTROLLER
 844         .ndo_poll_controller = virtnet_netpoll,
 845 #endif
 846 };
 847
 848 static void virtnet_update_status(struct virtnet_info *vi)
 849 {
 850         u16 v;
 851
 852         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS))
 853                 return;
 854
 855         vi->vdev->config->get(vi->vdev,
 856                               offsetof(struct virtio_net_config, status),
 857                               &v, sizeof(v));
 858
 859         /* Ignore unknown (future) status bits */
 860         v &= VIRTIO_NET_S_LINK_UP;
 861
 862         if (vi->status == v)
 863                 return;
 864
 865         vi->status = v;
 866
 867         if (vi->status & VIRTIO_NET_S_LINK_UP) {
 868                 netif_carrier_on(vi->dev);
 869                 netif_wake_queue(vi->dev);
 870         } else {
 871                 netif_carrier_off(vi->dev);
 872                 netif_stop_queue(vi->dev);
 873         }
 874 }
 875
 876 static void virtnet_config_changed(struct virtio_device *vdev)
 877 {
 878         struct virtnet_info *vi = vdev->priv;
 879
 880         virtnet_update_status(vi);
 881 }
 882
 883 static int virtnet_probe(struct virtio_device *vdev)
 884 {
 885         int err;
 886         struct net_device *dev;
 887         struct virtnet_info *vi;
 888         struct virtqueue *vqs[3];
 889         vq_callback_t *callbacks[] = { skb_recv_done, skb_xmit_done, NULL};
 890         const char *names[] = { "input", "output", "control" };
 891         int nvqs;
 892
 893         /* Allocate ourselves a network device with room for our info */
 894         dev = alloc_etherdev(sizeof(struct virtnet_info));
 895         if (!dev)
 896                 return -ENOMEM;
 897
 898         /* Set up network device as normal. */
 899         dev->netdev_ops = &virtnet_netdev;
 900         dev->features = NETIF_F_HIGHDMA;
 901         SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
 902         SET_NETDEV_DEV(dev, &vdev->dev);
 903
 904         /* Do we support "hardware" checksums? */
 905         if (csum && virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
 906                 /* This opens up the world of extra features. */
 907                 dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
 908                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
 909                         dev->features |= NETIF_F_TSO | NETIF_F_UFO
 910                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
 911                 }
 912                 /* Individual feature bits: what can host handle? */
 913                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
 914                         dev->features |= NETIF_F_TSO;
 915                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
 916                         dev->features |= NETIF_F_TSO6;
 917                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
 918                         dev->features |= NETIF_F_TSO_ECN;
 919                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
 920                         dev->features |= NETIF_F_UFO;
 921         }
 922
 923         /* Configuration may specify what MAC to use.  Otherwise random. */
 924         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
 925                 vdev->config->get(vdev,
 926                                   offsetof(struct virtio_net_config, mac),
 927                                   dev->dev_addr, dev->addr_len);
 928         } else
 929                 random_ether_addr(dev->dev_addr);
 930
 931         /* Set up our device-specific information */
 932         vi = netdev_priv(dev);
 933         netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
 934         vi->dev = dev;
 935         vi->vdev = vdev;
 936         vdev->priv = vi;
 937         vi->pages = NULL;
 938         INIT_DELAYED_WORK(&vi->refill, refill_work);
 939         sg_init_table(vi->rx_sg, ARRAY_SIZE(vi->rx_sg));
 940         sg_init_table(vi->tx_sg, ARRAY_SIZE(vi->tx_sg));
 941
 942         /* If we can receive ANY GSO packets, we must allocate large ones. */
 943         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
 944             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
 945             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
 946                 vi->big_packets = true;
 947
 948         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
 949                 vi->mergeable_rx_bufs = true;
 950
 951         /* We expect two virtqueues, receive then send,
 952          * and optionally control. */
 953         nvqs = virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ? 3 : 2;
 954
 955         err = vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names);
 956         if (err)
 957                 goto free;
 958
 959         vi->rvq = vqs[0];
 960         vi->svq = vqs[1];
 961
 962         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
 963                 vi->cvq = vqs[2];
 964
 965                 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
 966                         dev->features |= NETIF_F_HW_VLAN_FILTER;
 967         }
 968
 969         err = register_netdev(dev);
 970         if (err) {
 971                 pr_debug("virtio_net: registering device failed\n");
 972                 goto free_vqs;
 973         }
 974
 975         /* Last of all, set up some receive buffers. */
 976         try_fill_recv(vi, GFP_KERNEL);
 977
 978         /* If we didn't even get one input buffer, we're useless. */
 979         if (vi->num == 0) {
 980                 err = -ENOMEM;
 981                 goto unregister;
 982         }
 983
 984         vi->status = VIRTIO_NET_S_LINK_UP;
 985         virtnet_update_status(vi);
 986         netif_carrier_on(dev);
 987
 988         pr_debug("virtnet: registered device %s\n", dev->name);
 989         return 0;
 990
 991 unregister:
 992         unregister_netdev(dev);
 993         cancel_delayed_work_sync(&vi->refill);
 994 free_vqs:
 995         vdev->config->del_vqs(vdev);
 996 free:
 997         free_netdev(dev);
 998         return err;
 999 }
1000
1001 static void free_unused_bufs(struct virtnet_info *vi)
1002 {
1003         void *buf;
1004         while (1) {
1005                 buf = vi->svq->vq_ops->detach_unused_buf(vi->svq);
1006                 if (!buf)
1007                         break;
1008                 dev_kfree_skb(buf);
1009         }
1010         while (1) {
1011                 buf = vi->rvq->vq_ops->detach_unused_buf(vi->rvq);
1012                 if (!buf)
1013                         break;
1014                 if (vi->mergeable_rx_bufs || vi->big_packets)
1015                         give_pages(vi, buf);
1016                 else
1017                         dev_kfree_skb(buf);
1018                 --vi->num;
1019         }
1020         BUG_ON(vi->num != 0);
1021 }
1022
1023 static void __devexit virtnet_remove(struct virtio_device *vdev)
1024 {
1025         struct virtnet_info *vi = vdev->priv;
1026
1027         /* Stop all the virtqueues. */
1028         vdev->config->reset(vdev);
1029
1030
1031         unregister_netdev(vi->dev);
1032         cancel_delayed_work_sync(&vi->refill);
1033
1034         /* Free unused buffers in both send and recv, if any. */
1035         free_unused_bufs(vi);
1036
1037         vdev->config->del_vqs(vi->vdev);
1038
1039         while (vi->pages)
1040                 __free_pages(get_a_page(vi, GFP_KERNEL), 0);
1041
1042         free_netdev(vi->dev);
1043 }
1044
1045 static struct virtio_device_id id_table[] = {
1046         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1047         { 0 },
1048 };
1049
1050 static unsigned int features[] = {
1051         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1052         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1053         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
1054         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1055         VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
1056         VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
1057         VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
1058 };
1059
1060 static struct virtio_driver virtio_net_driver = {
1061         .feature_table = features,
1062         .feature_table_size = ARRAY_SIZE(features),
1063         .driver.name =  KBUILD_MODNAME,
1064         .driver.owner = THIS_MODULE,
1065         .id_table =     id_table,
1066         .probe =        virtnet_probe,
1067         .remove =       __devexit_p(virtnet_remove),
1068         .config_changed = virtnet_config_changed,
1069 };
1070
1071 static int __init init(void)
1072 {
1073         return register_virtio_driver(&virtio_net_driver);
1074 }
1075
1076 static void __exit fini(void)
1077 {
1078         unregister_virtio_driver(&virtio_net_driver);
1079 }
1080 module_init(init);
1081 module_exit(fini);
1082
1083 MODULE_DEVICE_TABLE(virtio, id_table);
1084 MODULE_DESCRIPTION("Virtio network driver");
1085 MODULE_LICENSE("GPL");