SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 #include <linux/slab.h>
  29
  30 static int napi_weight = 128;
  31 module_param(napi_weight, int, 0444);
  32
  33 static int csum = 1, gso = 1;
  34 module_param(csum, bool, 0444);
  35 module_param(gso, bool, 0444);
  36
  37 /* FIXME: MTU in config. */
  38 #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
  39 #define GOOD_COPY_LEN   128
  40
  41 #define VIRTNET_SEND_COMMAND_SG_MAX    2
  42
  43 struct virtnet_info
  44 {
  45         struct virtio_device *vdev;
  46         struct virtqueue *rvq, *svq, *cvq;
  47         struct net_device *dev;
  48         struct napi_struct napi;
  49         unsigned int status;
  50
  51         /* Number of input buffers, and max we've ever had. */
  52         unsigned int num, max;
  53
  54         /* I like... big packets and I cannot lie! */
  55         bool big_packets;
  56
  57         /* Host will merge rx buffers for big packets (shake it! shake it!) */
  58         bool mergeable_rx_bufs;
  59
  60         /* Work struct for refilling if we run low on memory. */
  61         struct delayed_work refill;
  62
  63         /* Chain pages by the private ptr. */
  64         struct page *pages;
  65 };
  66
  67 struct skb_vnet_hdr {
  68         union {
  69                 struct virtio_net_hdr hdr;
  70                 struct virtio_net_hdr_mrg_rxbuf mhdr;
  71         };
  72         unsigned int num_sg;
  73 };
  74
  75 struct padded_vnet_hdr {
  76         struct virtio_net_hdr hdr;
  77         /*
  78          * virtio_net_hdr should be in a separated sg buffer because of a
  79          * QEMU bug, and data sg buffer shares same page with this header sg.
  80          * This padding makes next sg 16 byte aligned after virtio_net_hdr.
  81          */
  82         char padding[6];
  83 };
  84
  85 static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
  86 {
  87         return (struct skb_vnet_hdr *)skb->cb;
  88 }
  89
  90 /*
  91  * private is used to chain pages for big packets, put the whole
  92  * most recent used list in the beginning for reuse
  93  */
  94 static void give_pages(struct virtnet_info *vi, struct page *page)
  95 {
  96         struct page *end;
  97
  98         /* Find end of list, sew whole thing into vi->pages. */
  99         for (end = page; end->private; end = (struct page *)end->private);
 100         end->private = (unsigned long)vi->pages;
 101         vi->pages = page;
 102 }
 103
 104 static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
 105 {
 106         struct page *p = vi->pages;
 107
 108         if (p) {
 109                 vi->pages = (struct page *)p->private;
 110                 /* clear private here, it is used to chain pages */
 111                 p->private = 0;
 112         } else
 113                 p = alloc_page(gfp_mask);
 114         return p;
 115 }
 116
 117 static void skb_xmit_done(struct virtqueue *svq)
 118 {
 119         struct virtnet_info *vi = svq->vdev->priv;
 120
 121         /* Suppress further interrupts. */
 122         svq->vq_ops->disable_cb(svq);
 123
 124         /* We were probably waiting for more output buffers. */
 125         netif_wake_queue(vi->dev);
 126 }
 127
 128 static void set_skb_frag(struct sk_buff *skb, struct page *page,
 129                          unsigned int offset, unsigned int *len)
 130 {
 131         int i = skb_shinfo(skb)->nr_frags;
 132         skb_frag_t *f;
 133
 134         f = &skb_shinfo(skb)->frags[i];
 135         f->size = min((unsigned)PAGE_SIZE - offset, *len);
 136         f->page_offset = offset;
 137         f->page = page;
 138
 139         skb->data_len += f->size;
 140         skb->len += f->size;
 141         skb_shinfo(skb)->nr_frags++;
 142         *len -= f->size;
 143 }
 144
 145 static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 146                                    struct page *page, unsigned int len)
 147 {
 148         struct sk_buff *skb;
 149         struct skb_vnet_hdr *hdr;
 150         unsigned int copy, hdr_len, offset;
 151         char *p;
 152
 153         p = page_address(page);
 154
 155         /* copy small packet so we can reuse these pages for small data */
 156         skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
 157         if (unlikely(!skb))
 158                 return NULL;
 159
 160         hdr = skb_vnet_hdr(skb);
 161
 162         if (vi->mergeable_rx_bufs) {
 163                 hdr_len = sizeof hdr->mhdr;
 164                 offset = hdr_len;
 165         } else {
 166                 hdr_len = sizeof hdr->hdr;
 167                 offset = sizeof(struct padded_vnet_hdr);
 168         }
 169
 170         memcpy(hdr, p, hdr_len);
 171
 172         len -= hdr_len;
 173         p += offset;
 174
 175         copy = len;
 176         if (copy > skb_tailroom(skb))
 177                 copy = skb_tailroom(skb);
 178         memcpy(skb_put(skb, copy), p, copy);
 179
 180         len -= copy;
 181         offset += copy;
 182
 183         while (len) {
 184                 set_skb_frag(skb, page, offset, &len);
 185                 page = (struct page *)page->private;
 186                 offset = 0;
 187         }
 188
 189         if (page)
 190                 give_pages(vi, page);
 191
 192         return skb;
 193 }
 194
 195 static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb)
 196 {
 197         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 198         struct page *page;
 199         int num_buf, i, len;
 200
 201         num_buf = hdr->mhdr.num_buffers;
 202         while (--num_buf) {
 203                 i = skb_shinfo(skb)->nr_frags;
 204                 if (i >= MAX_SKB_FRAGS) {
 205                         pr_debug("%s: packet too long\n", skb->dev->name);
 206                         skb->dev->stats.rx_length_errors++;
 207                         return -EINVAL;
 208                 }
 209
 210                 page = vi->rvq->vq_ops->get_buf(vi->rvq, &len);
 211                 if (!page) {
 212                         pr_debug("%s: rx error: %d buffers missing\n",
 213                                  skb->dev->name, hdr->mhdr.num_buffers);
 214                         skb->dev->stats.rx_length_errors++;
 215                         return -EINVAL;
 216                 }
 217                 if (len > PAGE_SIZE)
 218                         len = PAGE_SIZE;
 219
 220                 set_skb_frag(skb, page, 0, &len);
 221
 222                 --vi->num;
 223         }
 224         return 0;
 225 }
 226
 227 static void receive_buf(struct net_device *dev, void *buf, unsigned int len)
 228 {
 229         struct virtnet_info *vi = netdev_priv(dev);
 230         struct sk_buff *skb;
 231         struct page *page;
 232         struct skb_vnet_hdr *hdr;
 233
 234         if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
 235                 pr_debug("%s: short packet %i\n", dev->name, len);
 236                 dev->stats.rx_length_errors++;
 237                 if (vi->mergeable_rx_bufs || vi->big_packets)
 238                         give_pages(vi, buf);
 239                 else
 240                         dev_kfree_skb(buf);
 241                 return;
 242         }
 243
 244         if (!vi->mergeable_rx_bufs && !vi->big_packets) {
 245                 skb = buf;
 246                 len -= sizeof(struct virtio_net_hdr);
 247                 skb_trim(skb, len);
 248         } else {
 249                 page = buf;
 250                 skb = page_to_skb(vi, page, len);
 251                 if (unlikely(!skb)) {
 252                         dev->stats.rx_dropped++;
 253                         give_pages(vi, page);
 254                         return;
 255                 }
 256                 if (vi->mergeable_rx_bufs)
 257                         if (receive_mergeable(vi, skb)) {
 258                                 dev_kfree_skb(skb);
 259                                 return;
 260                         }
 261         }
 262
 263         hdr = skb_vnet_hdr(skb);
 264         skb->truesize += skb->data_len;
 265         dev->stats.rx_bytes += skb->len;
 266         dev->stats.rx_packets++;
 267
 268         if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 269                 pr_debug("Needs csum!\n");
 270                 if (!skb_partial_csum_set(skb,
 271                                           hdr->hdr.csum_start,
 272                                           hdr->hdr.csum_offset))
 273                         goto frame_err;
 274         }
 275
 276         skb->protocol = eth_type_trans(skb, dev);
 277         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
 278                  ntohs(skb->protocol), skb->len, skb->pkt_type);
 279
 280         if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 281                 pr_debug("GSO!\n");
 282                 switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 283                 case VIRTIO_NET_HDR_GSO_TCPV4:
 284                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 285                         break;
 286                 case VIRTIO_NET_HDR_GSO_UDP:
 287                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 288                         break;
 289                 case VIRTIO_NET_HDR_GSO_TCPV6:
 290                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 291                         break;
 292                 default:
 293                         if (net_ratelimit())
 294                                 printk(KERN_WARNING "%s: bad gso type %u.\n",
 295                                        dev->name, hdr->hdr.gso_type);
 296                         goto frame_err;
 297                 }
 298
 299                 if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 300                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 301
 302                 skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
 303                 if (skb_shinfo(skb)->gso_size == 0) {
 304                         if (net_ratelimit())
 305                                 printk(KERN_WARNING "%s: zero gso size.\n",
 306                                        dev->name);
 307                         goto frame_err;
 308                 }
 309
 310                 /* Header must be checked, and gso_segs computed. */
 311                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 312                 skb_shinfo(skb)->gso_segs = 0;
 313         }
 314
 315         netif_receive_skb(skb);
 316         return;
 317
 318 frame_err:
 319         dev->stats.rx_frame_errors++;
 320         dev_kfree_skb(skb);
 321 }
 322
 323 static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp)
 324 {
 325         struct sk_buff *skb;
 326         struct skb_vnet_hdr *hdr;
 327         struct scatterlist sg[2];
 328         int err;
 329
 330         skb = netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN);
 331         if (unlikely(!skb))
 332                 return -ENOMEM;
 333
 334         skb_put(skb, MAX_PACKET_LEN);
 335
 336         hdr = skb_vnet_hdr(skb);
 337         sg_set_buf(sg, &hdr->hdr, sizeof hdr->hdr);
 338
 339         skb_to_sgvec(skb, sg + 1, 0, skb->len);
 340
 341         err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, 2, skb);
 342         if (err < 0)
 343                 dev_kfree_skb(skb);
 344
 345         return err;
 346 }
 347
 348 static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp)
 349 {
 350         struct scatterlist sg[MAX_SKB_FRAGS + 2];
 351         struct page *first, *list = NULL;
 352         char *p;
 353         int i, err, offset;
 354
 355         /* page in 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(&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         /* sg[0], sg[1] share the same page */
 378         /* a separated sg[0] for  virtio_net_hdr only during to QEMU bug*/
 379         sg_set_buf(&sg[0], p, sizeof(struct virtio_net_hdr));
 380
 381         /* sg[1] for data packet, from offset */
 382         offset = sizeof(struct padded_vnet_hdr);
 383         sg_set_buf(&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, 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         struct scatterlist sg;
 399         int err;
 400
 401         page = get_a_page(vi, gfp);
 402         if (!page)
 403                 return -ENOMEM;
 404
 405         sg_init_one(&sg, page_address(page), PAGE_SIZE);
 406
 407         err = vi->rvq->vq_ops->add_buf(vi->rvq, &sg, 0, 1, page);
 408         if (err < 0)
 409                 give_pages(vi, page);
 410
 411         return err;
 412 }
 413
 414 /* Returns false if we couldn't fill entirely (OOM). */
 415 static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
 416 {
 417         int err;
 418         bool oom = false;
 419
 420         do {
 421                 if (vi->mergeable_rx_bufs)
 422                         err = add_recvbuf_mergeable(vi, gfp);
 423                 else if (vi->big_packets)
 424                         err = add_recvbuf_big(vi, gfp);
 425                 else
 426                         err = add_recvbuf_small(vi, gfp);
 427
 428                 if (err < 0) {
 429                         oom = true;
 430                         break;
 431                 }
 432                 ++vi->num;
 433         } while (err > 0);
 434         if (unlikely(vi->num > vi->max))
 435                 vi->max = vi->num;
 436         vi->rvq->vq_ops->kick(vi->rvq);
 437         return !oom;
 438 }
 439
 440 static void skb_recv_done(struct virtqueue *rvq)
 441 {
 442         struct virtnet_info *vi = rvq->vdev->priv;
 443         /* Schedule NAPI, Suppress further interrupts if successful. */
 444         if (napi_schedule_prep(&vi->napi)) {
 445                 rvq->vq_ops->disable_cb(rvq);
 446                 __napi_schedule(&vi->napi);
 447         }
 448 }
 449
 450 static void refill_work(struct work_struct *work)
 451 {
 452         struct virtnet_info *vi;
 453         bool still_empty;
 454
 455         vi = container_of(work, struct virtnet_info, refill.work);
 456         napi_disable(&vi->napi);
 457         still_empty = !try_fill_recv(vi, GFP_KERNEL);
 458         napi_enable(&vi->napi);
 459
 460         /* In theory, this can happen: if we don't get any buffers in
 461          * we will *never* try to fill again. */
 462         if (still_empty)
 463                 schedule_delayed_work(&vi->refill, HZ/2);
 464 }
 465
 466 static int virtnet_poll(struct napi_struct *napi, int budget)
 467 {
 468         struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
 469         void *buf;
 470         unsigned int len, received = 0;
 471
 472 again:
 473         while (received < budget &&
 474                (buf = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
 475                 receive_buf(vi->dev, buf, len);
 476                 --vi->num;
 477                 received++;
 478         }
 479
 480         if (vi->num < vi->max / 2) {
 481                 if (!try_fill_recv(vi, GFP_ATOMIC))
 482                         schedule_delayed_work(&vi->refill, 0);
 483         }
 484
 485         /* Out of packets? */
 486         if (received < budget) {
 487                 napi_complete(napi);
 488                 if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq)) &&
 489                     napi_schedule_prep(napi)) {
 490                         vi->rvq->vq_ops->disable_cb(vi->rvq);
 491                         __napi_schedule(napi);
 492                         goto again;
 493                 }
 494         }
 495
 496         return received;
 497 }
 498
 499 static unsigned int free_old_xmit_skbs(struct virtnet_info *vi)
 500 {
 501         struct sk_buff *skb;
 502         unsigned int len, tot_sgs = 0;
 503
 504         while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
 505                 pr_debug("Sent skb %p\n", skb);
 506                 vi->dev->stats.tx_bytes += skb->len;
 507                 vi->dev->stats.tx_packets++;
 508                 tot_sgs += skb_vnet_hdr(skb)->num_sg;
 509                 dev_kfree_skb_any(skb);
 510         }
 511         return tot_sgs;
 512 }
 513
 514 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
 515 {
 516         struct scatterlist sg[2+MAX_SKB_FRAGS];
 517         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 518         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 519
 520         sg_init_table(sg, 2+MAX_SKB_FRAGS);
 521
 522         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
 523
 524         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 525                 hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 526                 hdr->hdr.csum_start = skb->csum_start - skb_headroom(skb);
 527                 hdr->hdr.csum_offset = skb->csum_offset;
 528         } else {
 529                 hdr->hdr.flags = 0;
 530                 hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
 531         }
 532
 533         if (skb_is_gso(skb)) {
 534                 hdr->hdr.hdr_len = skb_headlen(skb);
 535                 hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
 536                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 537                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 538                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 539                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 540                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 541                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 542                 else
 543                         BUG();
 544                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
 545                         hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 546         } else {
 547                 hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 548                 hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
 549         }
 550
 551         hdr->mhdr.num_buffers = 0;
 552
 553         /* Encode metadata header at front. */
 554         if (vi->mergeable_rx_bufs)
 555                 sg_set_buf(sg, &hdr->mhdr, sizeof hdr->mhdr);
 556         else
 557                 sg_set_buf(sg, &hdr->hdr, sizeof hdr->hdr);
 558
 559         hdr->num_sg = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
 560         return vi->svq->vq_ops->add_buf(vi->svq, sg, hdr->num_sg, 0, skb);
 561 }
 562
 563 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 564 {
 565         struct virtnet_info *vi = netdev_priv(dev);
 566         int capacity;
 567
 568 again:
 569         /* Free up any pending old buffers before queueing new ones. */
 570         free_old_xmit_skbs(vi);
 571
 572         /* Try to transmit */
 573         capacity = xmit_skb(vi, skb);
 574
 575         /* This can happen with OOM and indirect buffers. */
 576         if (unlikely(capacity < 0)) {
 577                 netif_stop_queue(dev);
 578                 dev_warn(&dev->dev, "Unexpected full queue\n");
 579                 if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
 580                         vi->svq->vq_ops->disable_cb(vi->svq);
 581                         netif_start_queue(dev);
 582                         goto again;
 583                 }
 584                 return NETDEV_TX_BUSY;
 585         }
 586         vi->svq->vq_ops->kick(vi->svq);
 587
 588         /* Don't wait up for transmitted skbs to be freed. */
 589         skb_orphan(skb);
 590         nf_reset(skb);
 591
 592         /* Apparently nice girls don't return TX_BUSY; stop the queue
 593          * before it gets out of hand.  Naturally, this wastes entries. */
 594         if (capacity < 2+MAX_SKB_FRAGS) {
 595                 netif_stop_queue(dev);
 596                 if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
 597                         /* More just got used, free them then recheck. */
 598                         capacity += free_old_xmit_skbs(vi);
 599                         if (capacity >= 2+MAX_SKB_FRAGS) {
 600                                 netif_start_queue(dev);
 601                                 vi->svq->vq_ops->disable_cb(vi->svq);
 602                         }
 603                 }
 604         }
 605
 606         return NETDEV_TX_OK;
 607 }
 608
 609 static int virtnet_set_mac_address(struct net_device *dev, void *p)
 610 {
 611         struct virtnet_info *vi = netdev_priv(dev);
 612         struct virtio_device *vdev = vi->vdev;
 613         int ret;
 614
 615         ret = eth_mac_addr(dev, p);
 616         if (ret)
 617                 return ret;
 618
 619         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
 620                 vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
 621                                   dev->dev_addr, dev->addr_len);
 622
 623         return 0;
 624 }
 625
 626 #ifdef CONFIG_NET_POLL_CONTROLLER
 627 static void virtnet_netpoll(struct net_device *dev)
 628 {
 629         struct virtnet_info *vi = netdev_priv(dev);
 630
 631         napi_schedule(&vi->napi);
 632 }
 633 #endif
 634
 635 static int virtnet_open(struct net_device *dev)
 636 {
 637         struct virtnet_info *vi = netdev_priv(dev);
 638
 639         napi_enable(&vi->napi);
 640
 641         /* If all buffers were filled by other side before we napi_enabled, we
 642          * won't get another interrupt, so process any outstanding packets
 643          * now.  virtnet_poll wants re-enable the queue, so we disable here.
 644          * We synchronize against interrupts via NAPI_STATE_SCHED */
 645         if (napi_schedule_prep(&vi->napi)) {
 646                 vi->rvq->vq_ops->disable_cb(vi->rvq);
 647                 __napi_schedule(&vi->napi);
 648         }
 649         return 0;
 650 }
 651
 652 /*
 653  * Send command via the control virtqueue and check status.  Commands
 654  * supported by the hypervisor, as indicated by feature bits, should
 655  * never fail unless improperly formated.
 656  */
 657 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
 658                                  struct scatterlist *data, int out, int in)
 659 {
 660         struct scatterlist *s, sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
 661         struct virtio_net_ctrl_hdr ctrl;
 662         virtio_net_ctrl_ack status = ~0;
 663         unsigned int tmp;
 664         int i;
 665
 666         /* Caller should know better */
 667         BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ||
 668                 (out + in > VIRTNET_SEND_COMMAND_SG_MAX));
 669
 670         out++; /* Add header */
 671         in++; /* Add return status */
 672
 673         ctrl.class = class;
 674         ctrl.cmd = cmd;
 675
 676         sg_init_table(sg, out + in);
 677
 678         sg_set_buf(&sg[0], &ctrl, sizeof(ctrl));
 679         for_each_sg(data, s, out + in - 2, i)
 680                 sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
 681         sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
 682
 683         BUG_ON(vi->cvq->vq_ops->add_buf(vi->cvq, sg, out, in, vi) < 0);
 684
 685         vi->cvq->vq_ops->kick(vi->cvq);
 686
 687         /*
 688          * Spin for a response, the kick causes an ioport write, trapping
 689          * into the hypervisor, so the request should be handled immediately.
 690          */
 691         while (!vi->cvq->vq_ops->get_buf(vi->cvq, &tmp))
 692                 cpu_relax();
 693
 694         return status == VIRTIO_NET_OK;
 695 }
 696
 697 static int virtnet_close(struct net_device *dev)
 698 {
 699         struct virtnet_info *vi = netdev_priv(dev);
 700
 701         napi_disable(&vi->napi);
 702
 703         return 0;
 704 }
 705
 706 static int virtnet_set_tx_csum(struct net_device *dev, u32 data)
 707 {
 708         struct virtnet_info *vi = netdev_priv(dev);
 709         struct virtio_device *vdev = vi->vdev;
 710
 711         if (data && !virtio_has_feature(vdev, VIRTIO_NET_F_CSUM))
 712                 return -ENOSYS;
 713
 714         return ethtool_op_set_tx_hw_csum(dev, data);
 715 }
 716
 717 static void virtnet_set_rx_mode(struct net_device *dev)
 718 {
 719         struct virtnet_info *vi = netdev_priv(dev);
 720         struct scatterlist sg[2];
 721         u8 promisc, allmulti;
 722         struct virtio_net_ctrl_mac *mac_data;
 723         struct dev_addr_list *addr;
 724         struct netdev_hw_addr *ha;
 725         int uc_count;
 726         int mc_count;
 727         void *buf;
 728         int i;
 729
 730         /* We can't dynamicaly set ndo_set_rx_mode, so return gracefully */
 731         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
 732                 return;
 733
 734         promisc = ((dev->flags & IFF_PROMISC) != 0);
 735         allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
 736
 737         sg_init_one(sg, &promisc, sizeof(promisc));
 738
 739         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 740                                   VIRTIO_NET_CTRL_RX_PROMISC,
 741                                   sg, 1, 0))
 742                 dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
 743                          promisc ? "en" : "dis");
 744
 745         sg_init_one(sg, &allmulti, sizeof(allmulti));
 746
 747         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 748                                   VIRTIO_NET_CTRL_RX_ALLMULTI,
 749                                   sg, 1, 0))
 750                 dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
 751                          allmulti ? "en" : "dis");
 752
 753         uc_count = netdev_uc_count(dev);
 754         mc_count = netdev_mc_count(dev);
 755         /* MAC filter - use one buffer for both lists */
 756         buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
 757                       (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
 758         mac_data = buf;
 759         if (!buf) {
 760                 dev_warn(&dev->dev, "No memory for MAC address buffer\n");
 761                 return;
 762         }
 763
 764         sg_init_table(sg, 2);
 765
 766         /* Store the unicast list and count in the front of the buffer */
 767         mac_data->entries = uc_count;
 768         i = 0;
 769         netdev_for_each_uc_addr(ha, dev)
 770                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 771
 772         sg_set_buf(&sg[0], mac_data,
 773                    sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
 774
 775         /* multicast list and count fill the end */
 776         mac_data = (void *)&mac_data->macs[uc_count][0];
 777
 778         mac_data->entries = mc_count;
 779         i = 0;
 780         netdev_for_each_mc_addr(addr, dev)
 781                 memcpy(&mac_data->macs[i++][0], addr->da_addr, ETH_ALEN);
 782
 783         sg_set_buf(&sg[1], mac_data,
 784                    sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
 785
 786         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
 787                                   VIRTIO_NET_CTRL_MAC_TABLE_SET,
 788                                   sg, 2, 0))
 789                 dev_warn(&dev->dev, "Failed to set MAC fitler table.\n");
 790
 791         kfree(buf);
 792 }
 793
 794 static void virtnet_vlan_rx_add_vid(struct net_device *dev, u16 vid)
 795 {
 796         struct virtnet_info *vi = netdev_priv(dev);
 797         struct scatterlist sg;
 798
 799         sg_init_one(&sg, &vid, sizeof(vid));
 800
 801         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 802                                   VIRTIO_NET_CTRL_VLAN_ADD, &sg, 1, 0))
 803                 dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
 804 }
 805
 806 static void virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
 807 {
 808         struct virtnet_info *vi = netdev_priv(dev);
 809         struct scatterlist sg;
 810
 811         sg_init_one(&sg, &vid, sizeof(vid));
 812
 813         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 814                                   VIRTIO_NET_CTRL_VLAN_DEL, &sg, 1, 0))
 815                 dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
 816 }
 817
 818 static const struct ethtool_ops virtnet_ethtool_ops = {
 819         .set_tx_csum = virtnet_set_tx_csum,
 820         .set_sg = ethtool_op_set_sg,
 821         .set_tso = ethtool_op_set_tso,
 822         .set_ufo = ethtool_op_set_ufo,
 823         .get_link = ethtool_op_get_link,
 824 };
 825
 826 #define MIN_MTU 68
 827 #define MAX_MTU 65535
 828
 829 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
 830 {
 831         if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
 832                 return -EINVAL;
 833         dev->mtu = new_mtu;
 834         return 0;
 835 }
 836
 837 static const struct net_device_ops virtnet_netdev = {
 838         .ndo_open            = virtnet_open,
 839         .ndo_stop            = virtnet_close,
 840         .ndo_start_xmit      = start_xmit,
 841         .ndo_validate_addr   = eth_validate_addr,
 842         .ndo_set_mac_address = virtnet_set_mac_address,
 843         .ndo_set_rx_mode     = virtnet_set_rx_mode,
 844         .ndo_change_mtu      = virtnet_change_mtu,
 845         .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
 846         .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
 847 #ifdef CONFIG_NET_POLL_CONTROLLER
 848         .ndo_poll_controller = virtnet_netpoll,
 849 #endif
 850 };
 851
 852 static void virtnet_update_status(struct virtnet_info *vi)
 853 {
 854         u16 v;
 855
 856         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS))
 857                 return;
 858
 859         vi->vdev->config->get(vi->vdev,
 860                               offsetof(struct virtio_net_config, status),
 861                               &v, sizeof(v));
 862
 863         /* Ignore unknown (future) status bits */
 864         v &= VIRTIO_NET_S_LINK_UP;
 865
 866         if (vi->status == v)
 867                 return;
 868
 869         vi->status = v;
 870
 871         if (vi->status & VIRTIO_NET_S_LINK_UP) {
 872                 netif_carrier_on(vi->dev);
 873                 netif_wake_queue(vi->dev);
 874         } else {
 875                 netif_carrier_off(vi->dev);
 876                 netif_stop_queue(vi->dev);
 877         }
 878 }
 879
 880 static void virtnet_config_changed(struct virtio_device *vdev)
 881 {
 882         struct virtnet_info *vi = vdev->priv;
 883
 884         virtnet_update_status(vi);
 885 }
 886
 887 static int virtnet_probe(struct virtio_device *vdev)
 888 {
 889         int err;
 890         struct net_device *dev;
 891         struct virtnet_info *vi;
 892         struct virtqueue *vqs[3];
 893         vq_callback_t *callbacks[] = { skb_recv_done, skb_xmit_done, NULL};
 894         const char *names[] = { "input", "output", "control" };
 895         int nvqs;
 896
 897         /* Allocate ourselves a network device with room for our info */
 898         dev = alloc_etherdev(sizeof(struct virtnet_info));
 899         if (!dev)
 900                 return -ENOMEM;
 901
 902         /* Set up network device as normal. */
 903         dev->netdev_ops = &virtnet_netdev;
 904         dev->features = NETIF_F_HIGHDMA;
 905         SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
 906         SET_NETDEV_DEV(dev, &vdev->dev);
 907
 908         /* Do we support "hardware" checksums? */
 909         if (csum && virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
 910                 /* This opens up the world of extra features. */
 911                 dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
 912                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
 913                         dev->features |= NETIF_F_TSO | NETIF_F_UFO
 914                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
 915                 }
 916                 /* Individual feature bits: what can host handle? */
 917                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
 918                         dev->features |= NETIF_F_TSO;
 919                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
 920                         dev->features |= NETIF_F_TSO6;
 921                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
 922                         dev->features |= NETIF_F_TSO_ECN;
 923                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
 924                         dev->features |= NETIF_F_UFO;
 925         }
 926
 927         /* Configuration may specify what MAC to use.  Otherwise random. */
 928         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
 929                 vdev->config->get(vdev,
 930                                   offsetof(struct virtio_net_config, mac),
 931                                   dev->dev_addr, dev->addr_len);
 932         } else
 933                 random_ether_addr(dev->dev_addr);
 934
 935         /* Set up our device-specific information */
 936         vi = netdev_priv(dev);
 937         netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
 938         vi->dev = dev;
 939         vi->vdev = vdev;
 940         vdev->priv = vi;
 941         vi->pages = NULL;
 942         INIT_DELAYED_WORK(&vi->refill, refill_work);
 943
 944         /* If we can receive ANY GSO packets, we must allocate large ones. */
 945         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
 946             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
 947             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
 948                 vi->big_packets = true;
 949
 950         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
 951                 vi->mergeable_rx_bufs = true;
 952
 953         /* We expect two virtqueues, receive then send,
 954          * and optionally control. */
 955         nvqs = virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ? 3 : 2;
 956
 957         err = vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names);
 958         if (err)
 959                 goto free;
 960
 961         vi->rvq = vqs[0];
 962         vi->svq = vqs[1];
 963
 964         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
 965                 vi->cvq = vqs[2];
 966
 967                 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
 968                         dev->features |= NETIF_F_HW_VLAN_FILTER;
 969         }
 970
 971         err = register_netdev(dev);
 972         if (err) {
 973                 pr_debug("virtio_net: registering device failed\n");
 974                 goto free_vqs;
 975         }
 976
 977         /* Last of all, set up some receive buffers. */
 978         try_fill_recv(vi, GFP_KERNEL);
 979
 980         /* If we didn't even get one input buffer, we're useless. */
 981         if (vi->num == 0) {
 982                 err = -ENOMEM;
 983                 goto unregister;
 984         }
 985
 986         vi->status = VIRTIO_NET_S_LINK_UP;
 987         virtnet_update_status(vi);
 988         netif_carrier_on(dev);
 989
 990         pr_debug("virtnet: registered device %s\n", dev->name);
 991         return 0;
 992
 993 unregister:
 994         unregister_netdev(dev);
 995         cancel_delayed_work_sync(&vi->refill);
 996 free_vqs:
 997         vdev->config->del_vqs(vdev);
 998 free:
 999         free_netdev(dev);
1000         return err;
1001 }
1002
1003 static void free_unused_bufs(struct virtnet_info *vi)
1004 {
1005         void *buf;
1006         while (1) {
1007                 buf = vi->svq->vq_ops->detach_unused_buf(vi->svq);
1008                 if (!buf)
1009                         break;
1010                 dev_kfree_skb(buf);
1011         }
1012         while (1) {
1013                 buf = vi->rvq->vq_ops->detach_unused_buf(vi->rvq);
1014                 if (!buf)
1015                         break;
1016                 if (vi->mergeable_rx_bufs || vi->big_packets)
1017                         give_pages(vi, buf);
1018                 else
1019                         dev_kfree_skb(buf);
1020                 --vi->num;
1021         }
1022         BUG_ON(vi->num != 0);
1023 }
1024
1025 static void __devexit virtnet_remove(struct virtio_device *vdev)
1026 {
1027         struct virtnet_info *vi = vdev->priv;
1028
1029         /* Stop all the virtqueues. */
1030         vdev->config->reset(vdev);
1031
1032
1033         unregister_netdev(vi->dev);
1034         cancel_delayed_work_sync(&vi->refill);
1035
1036         /* Free unused buffers in both send and recv, if any. */
1037         free_unused_bufs(vi);
1038
1039         vdev->config->del_vqs(vi->vdev);
1040
1041         while (vi->pages)
1042                 __free_pages(get_a_page(vi, GFP_KERNEL), 0);
1043
1044         free_netdev(vi->dev);
1045 }
1046
1047 static struct virtio_device_id id_table[] = {
1048         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1049         { 0 },
1050 };
1051
1052 static unsigned int features[] = {
1053         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1054         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1055         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
1056         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1057         VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
1058         VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
1059         VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
1060 };
1061
1062 static struct virtio_driver virtio_net_driver = {
1063         .feature_table = features,
1064         .feature_table_size = ARRAY_SIZE(features),
1065         .driver.name =  KBUILD_MODNAME,
1066         .driver.owner = THIS_MODULE,
1067         .id_table =     id_table,
1068         .probe =        virtnet_probe,
1069         .remove =       __devexit_p(virtnet_remove),
1070         .config_changed = virtnet_config_changed,
1071 };
1072
1073 static int __init init(void)
1074 {
1075         return register_virtio_driver(&virtio_net_driver);
1076 }
1077
1078 static void __exit fini(void)
1079 {
1080         unregister_virtio_driver(&virtio_net_driver);
1081 }
1082 module_init(init);
1083 module_exit(fini);
1084
1085 MODULE_DEVICE_TABLE(virtio, id_table);
1086 MODULE_DESCRIPTION("Virtio network driver");
1087 MODULE_LICENSE("GPL");