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 #define VIRTNET_DRIVER_VERSION "1.0.0"
  43
  44 struct virtnet_stats {
  45         struct u64_stats_sync syncp;
  46         u64 tx_bytes;
  47         u64 tx_packets;
  48
  49         u64 rx_bytes;
  50         u64 rx_packets;
  51 };
  52
  53 struct virtnet_info {
  54         struct virtio_device *vdev;
  55         struct virtqueue *rvq, *svq, *cvq;
  56         struct net_device *dev;
  57         struct napi_struct napi;
  58         unsigned int status;
  59
  60         /* Number of input buffers, and max we've ever had. */
  61         unsigned int num, max;
  62
  63         /* I like... big packets and I cannot lie! */
  64         bool big_packets;
  65
  66         /* Host will merge rx buffers for big packets (shake it! shake it!) */
  67         bool mergeable_rx_bufs;
  68
  69         /* Active statistics */
  70         struct virtnet_stats __percpu *stats;
  71
  72         /* Work struct for refilling if we run low on memory. */
  73         struct delayed_work refill;
  74
  75         /* Chain pages by the private ptr. */
  76         struct page *pages;
  77
  78         /* fragments + linear part + virtio header */
  79         struct scatterlist rx_sg[MAX_SKB_FRAGS + 2];
  80         struct scatterlist tx_sg[MAX_SKB_FRAGS + 2];
  81 };
  82
  83 struct skb_vnet_hdr {
  84         union {
  85                 struct virtio_net_hdr hdr;
  86                 struct virtio_net_hdr_mrg_rxbuf mhdr;
  87         };
  88         unsigned int num_sg;
  89 };
  90
  91 struct padded_vnet_hdr {
  92         struct virtio_net_hdr hdr;
  93         /*
  94          * virtio_net_hdr should be in a separated sg buffer because of a
  95          * QEMU bug, and data sg buffer shares same page with this header sg.
  96          * This padding makes next sg 16 byte aligned after virtio_net_hdr.
  97          */
  98         char padding[6];
  99 };
 100
 101 static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
 102 {
 103         return (struct skb_vnet_hdr *)skb->cb;
 104 }
 105
 106 /*
 107  * private is used to chain pages for big packets, put the whole
 108  * most recent used list in the beginning for reuse
 109  */
 110 static void give_pages(struct virtnet_info *vi, struct page *page)
 111 {
 112         struct page *end;
 113
 114         /* Find end of list, sew whole thing into vi->pages. */
 115         for (end = page; end->private; end = (struct page *)end->private);
 116         end->private = (unsigned long)vi->pages;
 117         vi->pages = page;
 118 }
 119
 120 static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
 121 {
 122         struct page *p = vi->pages;
 123
 124         if (p) {
 125                 vi->pages = (struct page *)p->private;
 126                 /* clear private here, it is used to chain pages */
 127                 p->private = 0;
 128         } else
 129                 p = alloc_page(gfp_mask);
 130         return p;
 131 }
 132
 133 static void skb_xmit_done(struct virtqueue *svq)
 134 {
 135         struct virtnet_info *vi = svq->vdev->priv;
 136
 137         /* Suppress further interrupts. */
 138         virtqueue_disable_cb(svq);
 139
 140         /* We were probably waiting for more output buffers. */
 141         netif_wake_queue(vi->dev);
 142 }
 143
 144 static void set_skb_frag(struct sk_buff *skb, struct page *page,
 145                          unsigned int offset, unsigned int *len)
 146 {
 147         int size = min((unsigned)PAGE_SIZE - offset, *len);
 148         int i = skb_shinfo(skb)->nr_frags;
 149
 150         __skb_fill_page_desc(skb, i, page, offset, size);
 151
 152         skb->data_len += size;
 153         skb->len += size;
 154         skb->truesize += PAGE_SIZE;
 155         skb_shinfo(skb)->nr_frags++;
 156         *len -= size;
 157 }
 158
 159 static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 160                                    struct page *page, unsigned int len)
 161 {
 162         struct sk_buff *skb;
 163         struct skb_vnet_hdr *hdr;
 164         unsigned int copy, hdr_len, offset;
 165         char *p;
 166
 167         p = page_address(page);
 168
 169         /* copy small packet so we can reuse these pages for small data */
 170         skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
 171         if (unlikely(!skb))
 172                 return NULL;
 173
 174         hdr = skb_vnet_hdr(skb);
 175
 176         if (vi->mergeable_rx_bufs) {
 177                 hdr_len = sizeof hdr->mhdr;
 178                 offset = hdr_len;
 179         } else {
 180                 hdr_len = sizeof hdr->hdr;
 181                 offset = sizeof(struct padded_vnet_hdr);
 182         }
 183
 184         memcpy(hdr, p, hdr_len);
 185
 186         len -= hdr_len;
 187         p += offset;
 188
 189         copy = len;
 190         if (copy > skb_tailroom(skb))
 191                 copy = skb_tailroom(skb);
 192         memcpy(skb_put(skb, copy), p, copy);
 193
 194         len -= copy;
 195         offset += copy;
 196
 197         /*
 198          * Verify that we can indeed put this data into a skb.
 199          * This is here to handle cases when the device erroneously
 200          * tries to receive more than is possible. This is usually
 201          * the case of a broken device.
 202          */
 203         if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
 204                 if (net_ratelimit())
 205                         pr_debug("%s: too much data\n", skb->dev->name);
 206                 dev_kfree_skb(skb);
 207                 return NULL;
 208         }
 209
 210         while (len) {
 211                 set_skb_frag(skb, page, offset, &len);
 212                 page = (struct page *)page->private;
 213                 offset = 0;
 214         }
 215
 216         if (page)
 217                 give_pages(vi, page);
 218
 219         return skb;
 220 }
 221
 222 static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb)
 223 {
 224         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 225         struct page *page;
 226         int num_buf, i, len;
 227
 228         num_buf = hdr->mhdr.num_buffers;
 229         while (--num_buf) {
 230                 i = skb_shinfo(skb)->nr_frags;
 231                 if (i >= MAX_SKB_FRAGS) {
 232                         pr_debug("%s: packet too long\n", skb->dev->name);
 233                         skb->dev->stats.rx_length_errors++;
 234                         return -EINVAL;
 235                 }
 236                 page = virtqueue_get_buf(vi->rvq, &len);
 237                 if (!page) {
 238                         pr_debug("%s: rx error: %d buffers missing\n",
 239                                  skb->dev->name, hdr->mhdr.num_buffers);
 240                         skb->dev->stats.rx_length_errors++;
 241                         return -EINVAL;
 242                 }
 243
 244                 if (len > PAGE_SIZE)
 245                         len = PAGE_SIZE;
 246
 247                 set_skb_frag(skb, page, 0, &len);
 248
 249                 --vi->num;
 250         }
 251         return 0;
 252 }
 253
 254 static void receive_buf(struct net_device *dev, void *buf, unsigned int len)
 255 {
 256         struct virtnet_info *vi = netdev_priv(dev);
 257         struct virtnet_stats __percpu *stats = this_cpu_ptr(vi->stats);
 258         struct sk_buff *skb;
 259         struct page *page;
 260         struct skb_vnet_hdr *hdr;
 261
 262         if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
 263                 pr_debug("%s: short packet %i\n", dev->name, len);
 264                 dev->stats.rx_length_errors++;
 265                 if (vi->mergeable_rx_bufs || vi->big_packets)
 266                         give_pages(vi, buf);
 267                 else
 268                         dev_kfree_skb(buf);
 269                 return;
 270         }
 271
 272         if (!vi->mergeable_rx_bufs && !vi->big_packets) {
 273                 skb = buf;
 274                 len -= sizeof(struct virtio_net_hdr);
 275                 skb_trim(skb, len);
 276         } else {
 277                 page = buf;
 278                 skb = page_to_skb(vi, page, len);
 279                 if (unlikely(!skb)) {
 280                         dev->stats.rx_dropped++;
 281                         give_pages(vi, page);
 282                         return;
 283                 }
 284                 if (vi->mergeable_rx_bufs)
 285                         if (receive_mergeable(vi, skb)) {
 286                                 dev_kfree_skb(skb);
 287                                 return;
 288                         }
 289         }
 290
 291         hdr = skb_vnet_hdr(skb);
 292
 293         u64_stats_update_begin(&stats->syncp);
 294         stats->rx_bytes += skb->len;
 295         stats->rx_packets++;
 296         u64_stats_update_end(&stats->syncp);
 297
 298         if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 299                 pr_debug("Needs csum!\n");
 300                 if (!skb_partial_csum_set(skb,
 301                                           hdr->hdr.csum_start,
 302                                           hdr->hdr.csum_offset))
 303                         goto frame_err;
 304         } else if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID) {
 305                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 306         }
 307
 308         skb->protocol = eth_type_trans(skb, dev);
 309         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
 310                  ntohs(skb->protocol), skb->len, skb->pkt_type);
 311
 312         if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 313                 pr_debug("GSO!\n");
 314                 switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 315                 case VIRTIO_NET_HDR_GSO_TCPV4:
 316                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 317                         break;
 318                 case VIRTIO_NET_HDR_GSO_UDP:
 319                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 320                         break;
 321                 case VIRTIO_NET_HDR_GSO_TCPV6:
 322                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 323                         break;
 324                 default:
 325                         if (net_ratelimit())
 326                                 printk(KERN_WARNING "%s: bad gso type %u.\n",
 327                                        dev->name, hdr->hdr.gso_type);
 328                         goto frame_err;
 329                 }
 330
 331                 if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 332                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 333
 334                 skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
 335                 if (skb_shinfo(skb)->gso_size == 0) {
 336                         if (net_ratelimit())
 337                                 printk(KERN_WARNING "%s: zero gso size.\n",
 338                                        dev->name);
 339                         goto frame_err;
 340                 }
 341
 342                 /* Header must be checked, and gso_segs computed. */
 343                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 344                 skb_shinfo(skb)->gso_segs = 0;
 345         }
 346
 347         netif_receive_skb(skb);
 348         return;
 349
 350 frame_err:
 351         dev->stats.rx_frame_errors++;
 352         dev_kfree_skb(skb);
 353 }
 354
 355 static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp)
 356 {
 357         struct sk_buff *skb;
 358         struct skb_vnet_hdr *hdr;
 359         int err;
 360
 361         skb = netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN);
 362         if (unlikely(!skb))
 363                 return -ENOMEM;
 364
 365         skb_put(skb, MAX_PACKET_LEN);
 366
 367         hdr = skb_vnet_hdr(skb);
 368         sg_set_buf(vi->rx_sg, &hdr->hdr, sizeof hdr->hdr);
 369
 370         skb_to_sgvec(skb, vi->rx_sg + 1, 0, skb->len);
 371
 372         err = virtqueue_add_buf_gfp(vi->rvq, vi->rx_sg, 0, 2, skb, gfp);
 373         if (err < 0)
 374                 dev_kfree_skb(skb);
 375
 376         return err;
 377 }
 378
 379 static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp)
 380 {
 381         struct page *first, *list = NULL;
 382         char *p;
 383         int i, err, offset;
 384
 385         /* page in vi->rx_sg[MAX_SKB_FRAGS + 1] is list tail */
 386         for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
 387                 first = get_a_page(vi, gfp);
 388                 if (!first) {
 389                         if (list)
 390                                 give_pages(vi, list);
 391                         return -ENOMEM;
 392                 }
 393                 sg_set_buf(&vi->rx_sg[i], page_address(first), PAGE_SIZE);
 394
 395                 /* chain new page in list head to match sg */
 396                 first->private = (unsigned long)list;
 397                 list = first;
 398         }
 399
 400         first = get_a_page(vi, gfp);
 401         if (!first) {
 402                 give_pages(vi, list);
 403                 return -ENOMEM;
 404         }
 405         p = page_address(first);
 406
 407         /* vi->rx_sg[0], vi->rx_sg[1] share the same page */
 408         /* a separated vi->rx_sg[0] for virtio_net_hdr only due to QEMU bug */
 409         sg_set_buf(&vi->rx_sg[0], p, sizeof(struct virtio_net_hdr));
 410
 411         /* vi->rx_sg[1] for data packet, from offset */
 412         offset = sizeof(struct padded_vnet_hdr);
 413         sg_set_buf(&vi->rx_sg[1], p + offset, PAGE_SIZE - offset);
 414
 415         /* chain first in list head */
 416         first->private = (unsigned long)list;
 417         err = virtqueue_add_buf_gfp(vi->rvq, vi->rx_sg, 0, MAX_SKB_FRAGS + 2,
 418                                     first, gfp);
 419         if (err < 0)
 420                 give_pages(vi, first);
 421
 422         return err;
 423 }
 424
 425 static int add_recvbuf_mergeable(struct virtnet_info *vi, gfp_t gfp)
 426 {
 427         struct page *page;
 428         int err;
 429
 430         page = get_a_page(vi, gfp);
 431         if (!page)
 432                 return -ENOMEM;
 433
 434         sg_init_one(vi->rx_sg, page_address(page), PAGE_SIZE);
 435
 436         err = virtqueue_add_buf_gfp(vi->rvq, vi->rx_sg, 0, 1, page, gfp);
 437         if (err < 0)
 438                 give_pages(vi, page);
 439
 440         return err;
 441 }
 442
 443 /* Returns false if we couldn't fill entirely (OOM). */
 444 static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
 445 {
 446         int err;
 447         bool oom;
 448
 449         do {
 450                 if (vi->mergeable_rx_bufs)
 451                         err = add_recvbuf_mergeable(vi, gfp);
 452                 else if (vi->big_packets)
 453                         err = add_recvbuf_big(vi, gfp);
 454                 else
 455                         err = add_recvbuf_small(vi, gfp);
 456
 457                 oom = err == -ENOMEM;
 458                 if (err < 0)
 459                         break;
 460                 ++vi->num;
 461         } while (err > 0);
 462         if (unlikely(vi->num > vi->max))
 463                 vi->max = vi->num;
 464         virtqueue_kick(vi->rvq);
 465         return !oom;
 466 }
 467
 468 static void skb_recv_done(struct virtqueue *rvq)
 469 {
 470         struct virtnet_info *vi = rvq->vdev->priv;
 471         /* Schedule NAPI, Suppress further interrupts if successful. */
 472         if (napi_schedule_prep(&vi->napi)) {
 473                 virtqueue_disable_cb(rvq);
 474                 __napi_schedule(&vi->napi);
 475         }
 476 }
 477
 478 static void virtnet_napi_enable(struct virtnet_info *vi)
 479 {
 480         napi_enable(&vi->napi);
 481
 482         /* If all buffers were filled by other side before we napi_enabled, we
 483          * won't get another interrupt, so process any outstanding packets
 484          * now.  virtnet_poll wants re-enable the queue, so we disable here.
 485          * We synchronize against interrupts via NAPI_STATE_SCHED */
 486         if (napi_schedule_prep(&vi->napi)) {
 487                 virtqueue_disable_cb(vi->rvq);
 488                 __napi_schedule(&vi->napi);
 489         }
 490 }
 491
 492 static void refill_work(struct work_struct *work)
 493 {
 494         struct virtnet_info *vi;
 495         bool still_empty;
 496
 497         vi = container_of(work, struct virtnet_info, refill.work);
 498         napi_disable(&vi->napi);
 499         still_empty = !try_fill_recv(vi, GFP_KERNEL);
 500         virtnet_napi_enable(vi);
 501
 502         /* In theory, this can happen: if we don't get any buffers in
 503          * we will *never* try to fill again. */
 504         if (still_empty)
 505                 schedule_delayed_work(&vi->refill, HZ/2);
 506 }
 507
 508 static int virtnet_poll(struct napi_struct *napi, int budget)
 509 {
 510         struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
 511         void *buf;
 512         unsigned int len, received = 0;
 513
 514 again:
 515         while (received < budget &&
 516                (buf = virtqueue_get_buf(vi->rvq, &len)) != NULL) {
 517                 receive_buf(vi->dev, buf, len);
 518                 --vi->num;
 519                 received++;
 520         }
 521
 522         if (vi->num < vi->max / 2) {
 523                 if (!try_fill_recv(vi, GFP_ATOMIC))
 524                         schedule_delayed_work(&vi->refill, 0);
 525         }
 526
 527         /* Out of packets? */
 528         if (received < budget) {
 529                 napi_complete(napi);
 530                 if (unlikely(!virtqueue_enable_cb(vi->rvq)) &&
 531                     napi_schedule_prep(napi)) {
 532                         virtqueue_disable_cb(vi->rvq);
 533                         __napi_schedule(napi);
 534                         goto again;
 535                 }
 536         }
 537
 538         return received;
 539 }
 540
 541 static unsigned int free_old_xmit_skbs(struct virtnet_info *vi)
 542 {
 543         struct sk_buff *skb;
 544         unsigned int len, tot_sgs = 0;
 545         struct virtnet_stats __percpu *stats = this_cpu_ptr(vi->stats);
 546
 547         while ((skb = virtqueue_get_buf(vi->svq, &len)) != NULL) {
 548                 pr_debug("Sent skb %p\n", skb);
 549
 550                 u64_stats_update_begin(&stats->syncp);
 551                 stats->tx_bytes += skb->len;
 552                 stats->tx_packets++;
 553                 u64_stats_update_end(&stats->syncp);
 554
 555                 tot_sgs += skb_vnet_hdr(skb)->num_sg;
 556                 dev_kfree_skb_any(skb);
 557         }
 558         return tot_sgs;
 559 }
 560
 561 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
 562 {
 563         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 564         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 565
 566         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
 567
 568         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 569                 hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 570                 hdr->hdr.csum_start = skb_checksum_start_offset(skb);
 571                 hdr->hdr.csum_offset = skb->csum_offset;
 572         } else {
 573                 hdr->hdr.flags = 0;
 574                 hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
 575         }
 576
 577         if (skb_is_gso(skb)) {
 578                 hdr->hdr.hdr_len = skb_headlen(skb);
 579                 hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
 580                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 581                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 582                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 583                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 584                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 585                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 586                 else
 587                         BUG();
 588                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
 589                         hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 590         } else {
 591                 hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 592                 hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
 593         }
 594
 595         hdr->mhdr.num_buffers = 0;
 596
 597         /* Encode metadata header at front. */
 598         if (vi->mergeable_rx_bufs)
 599                 sg_set_buf(vi->tx_sg, &hdr->mhdr, sizeof hdr->mhdr);
 600         else
 601                 sg_set_buf(vi->tx_sg, &hdr->hdr, sizeof hdr->hdr);
 602
 603         hdr->num_sg = skb_to_sgvec(skb, vi->tx_sg + 1, 0, skb->len) + 1;
 604         return virtqueue_add_buf(vi->svq, vi->tx_sg, hdr->num_sg,
 605                                         0, skb);
 606 }
 607
 608 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 609 {
 610         struct virtnet_info *vi = netdev_priv(dev);
 611         int capacity;
 612
 613         /* Free up any pending old buffers before queueing new ones. */
 614         free_old_xmit_skbs(vi);
 615
 616         /* Try to transmit */
 617         capacity = xmit_skb(vi, skb);
 618
 619         /* This can happen with OOM and indirect buffers. */
 620         if (unlikely(capacity < 0)) {
 621                 if (net_ratelimit()) {
 622                         if (likely(capacity == -ENOMEM)) {
 623                                 dev_warn(&dev->dev,
 624                                          "TX queue failure: out of memory\n");
 625                         } else {
 626                                 dev->stats.tx_fifo_errors++;
 627                                 dev_warn(&dev->dev,
 628                                          "Unexpected TX queue failure: %d\n",
 629                                          capacity);
 630                         }
 631                 }
 632                 dev->stats.tx_dropped++;
 633                 kfree_skb(skb);
 634                 return NETDEV_TX_OK;
 635         }
 636         virtqueue_kick(vi->svq);
 637
 638         /* Don't wait up for transmitted skbs to be freed. */
 639         skb_orphan(skb);
 640         nf_reset(skb);
 641
 642         /* Apparently nice girls don't return TX_BUSY; stop the queue
 643          * before it gets out of hand.  Naturally, this wastes entries. */
 644         if (capacity < 2+MAX_SKB_FRAGS) {
 645                 netif_stop_queue(dev);
 646                 if (unlikely(!virtqueue_enable_cb_delayed(vi->svq))) {
 647                         /* More just got used, free them then recheck. */
 648                         capacity += free_old_xmit_skbs(vi);
 649                         if (capacity >= 2+MAX_SKB_FRAGS) {
 650                                 netif_start_queue(dev);
 651                                 virtqueue_disable_cb(vi->svq);
 652                         }
 653                 }
 654         }
 655
 656         return NETDEV_TX_OK;
 657 }
 658
 659 static int virtnet_set_mac_address(struct net_device *dev, void *p)
 660 {
 661         struct virtnet_info *vi = netdev_priv(dev);
 662         struct virtio_device *vdev = vi->vdev;
 663         int ret;
 664
 665         ret = eth_mac_addr(dev, p);
 666         if (ret)
 667                 return ret;
 668
 669         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
 670                 vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
 671                                   dev->dev_addr, dev->addr_len);
 672
 673         return 0;
 674 }
 675
 676 static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
 677                                                struct rtnl_link_stats64 *tot)
 678 {
 679         struct virtnet_info *vi = netdev_priv(dev);
 680         int cpu;
 681         unsigned int start;
 682
 683         for_each_possible_cpu(cpu) {
 684                 struct virtnet_stats __percpu *stats
 685                         = per_cpu_ptr(vi->stats, cpu);
 686                 u64 tpackets, tbytes, rpackets, rbytes;
 687
 688                 do {
 689                         start = u64_stats_fetch_begin(&stats->syncp);
 690                         tpackets = stats->tx_packets;
 691                         tbytes   = stats->tx_bytes;
 692                         rpackets = stats->rx_packets;
 693                         rbytes   = stats->rx_bytes;
 694                 } while (u64_stats_fetch_retry(&stats->syncp, start));
 695
 696                 tot->rx_packets += rpackets;
 697                 tot->tx_packets += tpackets;
 698                 tot->rx_bytes   += rbytes;
 699                 tot->tx_bytes   += tbytes;
 700         }
 701
 702         tot->tx_dropped = dev->stats.tx_dropped;
 703         tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
 704         tot->rx_dropped = dev->stats.rx_dropped;
 705         tot->rx_length_errors = dev->stats.rx_length_errors;
 706         tot->rx_frame_errors = dev->stats.rx_frame_errors;
 707
 708         return tot;
 709 }
 710
 711 #ifdef CONFIG_NET_POLL_CONTROLLER
 712 static void virtnet_netpoll(struct net_device *dev)
 713 {
 714         struct virtnet_info *vi = netdev_priv(dev);
 715
 716         napi_schedule(&vi->napi);
 717 }
 718 #endif
 719
 720 static int virtnet_open(struct net_device *dev)
 721 {
 722         struct virtnet_info *vi = netdev_priv(dev);
 723
 724         virtnet_napi_enable(vi);
 725         return 0;
 726 }
 727
 728 /*
 729  * Send command via the control virtqueue and check status.  Commands
 730  * supported by the hypervisor, as indicated by feature bits, should
 731  * never fail unless improperly formated.
 732  */
 733 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
 734                                  struct scatterlist *data, int out, int in)
 735 {
 736         struct scatterlist *s, sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
 737         struct virtio_net_ctrl_hdr ctrl;
 738         virtio_net_ctrl_ack status = ~0;
 739         unsigned int tmp;
 740         int i;
 741
 742         /* Caller should know better */
 743         BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ||
 744                 (out + in > VIRTNET_SEND_COMMAND_SG_MAX));
 745
 746         out++; /* Add header */
 747         in++; /* Add return status */
 748
 749         ctrl.class = class;
 750         ctrl.cmd = cmd;
 751
 752         sg_init_table(sg, out + in);
 753
 754         sg_set_buf(&sg[0], &ctrl, sizeof(ctrl));
 755         for_each_sg(data, s, out + in - 2, i)
 756                 sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
 757         sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
 758
 759         BUG_ON(virtqueue_add_buf(vi->cvq, sg, out, in, vi) < 0);
 760
 761         virtqueue_kick(vi->cvq);
 762
 763         /*
 764          * Spin for a response, the kick causes an ioport write, trapping
 765          * into the hypervisor, so the request should be handled immediately.
 766          */
 767         while (!virtqueue_get_buf(vi->cvq, &tmp))
 768                 cpu_relax();
 769
 770         return status == VIRTIO_NET_OK;
 771 }
 772
 773 static int virtnet_close(struct net_device *dev)
 774 {
 775         struct virtnet_info *vi = netdev_priv(dev);
 776
 777         napi_disable(&vi->napi);
 778
 779         return 0;
 780 }
 781
 782 static void virtnet_set_rx_mode(struct net_device *dev)
 783 {
 784         struct virtnet_info *vi = netdev_priv(dev);
 785         struct scatterlist sg[2];
 786         u8 promisc, allmulti;
 787         struct virtio_net_ctrl_mac *mac_data;
 788         struct netdev_hw_addr *ha;
 789         int uc_count;
 790         int mc_count;
 791         void *buf;
 792         int i;
 793
 794         /* We can't dynamicaly set ndo_set_rx_mode, so return gracefully */
 795         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
 796                 return;
 797
 798         promisc = ((dev->flags & IFF_PROMISC) != 0);
 799         allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
 800
 801         sg_init_one(sg, &promisc, sizeof(promisc));
 802
 803         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 804                                   VIRTIO_NET_CTRL_RX_PROMISC,
 805                                   sg, 1, 0))
 806                 dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
 807                          promisc ? "en" : "dis");
 808
 809         sg_init_one(sg, &allmulti, sizeof(allmulti));
 810
 811         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 812                                   VIRTIO_NET_CTRL_RX_ALLMULTI,
 813                                   sg, 1, 0))
 814                 dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
 815                          allmulti ? "en" : "dis");
 816
 817         uc_count = netdev_uc_count(dev);
 818         mc_count = netdev_mc_count(dev);
 819         /* MAC filter - use one buffer for both lists */
 820         buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
 821                       (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
 822         mac_data = buf;
 823         if (!buf) {
 824                 dev_warn(&dev->dev, "No memory for MAC address buffer\n");
 825                 return;
 826         }
 827
 828         sg_init_table(sg, 2);
 829
 830         /* Store the unicast list and count in the front of the buffer */
 831         mac_data->entries = uc_count;
 832         i = 0;
 833         netdev_for_each_uc_addr(ha, dev)
 834                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 835
 836         sg_set_buf(&sg[0], mac_data,
 837                    sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
 838
 839         /* multicast list and count fill the end */
 840         mac_data = (void *)&mac_data->macs[uc_count][0];
 841
 842         mac_data->entries = mc_count;
 843         i = 0;
 844         netdev_for_each_mc_addr(ha, dev)
 845                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 846
 847         sg_set_buf(&sg[1], mac_data,
 848                    sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
 849
 850         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
 851                                   VIRTIO_NET_CTRL_MAC_TABLE_SET,
 852                                   sg, 2, 0))
 853                 dev_warn(&dev->dev, "Failed to set MAC fitler table.\n");
 854
 855         kfree(buf);
 856 }
 857
 858 static int virtnet_vlan_rx_add_vid(struct net_device *dev, u16 vid)
 859 {
 860         struct virtnet_info *vi = netdev_priv(dev);
 861         struct scatterlist sg;
 862
 863         sg_init_one(&sg, &vid, sizeof(vid));
 864
 865         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 866                                   VIRTIO_NET_CTRL_VLAN_ADD, &sg, 1, 0))
 867                 dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
 868         return 0;
 869 }
 870
 871 static int virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
 872 {
 873         struct virtnet_info *vi = netdev_priv(dev);
 874         struct scatterlist sg;
 875
 876         sg_init_one(&sg, &vid, sizeof(vid));
 877
 878         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 879                                   VIRTIO_NET_CTRL_VLAN_DEL, &sg, 1, 0))
 880                 dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
 881         return 0;
 882 }
 883
 884 static void virtnet_get_ringparam(struct net_device *dev,
 885                                 struct ethtool_ringparam *ring)
 886 {
 887         struct virtnet_info *vi = netdev_priv(dev);
 888
 889         ring->rx_max_pending = virtqueue_get_vring_size(vi->rvq);
 890         ring->tx_max_pending = virtqueue_get_vring_size(vi->svq);
 891         ring->rx_pending = ring->rx_max_pending;
 892         ring->tx_pending = ring->tx_max_pending;
 893
 894 }
 895
 896
 897 static void virtnet_get_drvinfo(struct net_device *dev,
 898                                 struct ethtool_drvinfo *info)
 899 {
 900         struct virtnet_info *vi = netdev_priv(dev);
 901         struct virtio_device *vdev = vi->vdev;
 902
 903         strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
 904         strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
 905         strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
 906
 907 }
 908
 909 static const struct ethtool_ops virtnet_ethtool_ops = {
 910         .get_drvinfo = virtnet_get_drvinfo,
 911         .get_link = ethtool_op_get_link,
 912         .get_ringparam = virtnet_get_ringparam,
 913 };
 914
 915 #define MIN_MTU 68
 916 #define MAX_MTU 65535
 917
 918 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
 919 {
 920         if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
 921                 return -EINVAL;
 922         dev->mtu = new_mtu;
 923         return 0;
 924 }
 925
 926 static const struct net_device_ops virtnet_netdev = {
 927         .ndo_open            = virtnet_open,
 928         .ndo_stop            = virtnet_close,
 929         .ndo_start_xmit      = start_xmit,
 930         .ndo_validate_addr   = eth_validate_addr,
 931         .ndo_set_mac_address = virtnet_set_mac_address,
 932         .ndo_set_rx_mode     = virtnet_set_rx_mode,
 933         .ndo_change_mtu      = virtnet_change_mtu,
 934         .ndo_get_stats64     = virtnet_stats,
 935         .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
 936         .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
 937 #ifdef CONFIG_NET_POLL_CONTROLLER
 938         .ndo_poll_controller = virtnet_netpoll,
 939 #endif
 940 };
 941
 942 static void virtnet_update_status(struct virtnet_info *vi)
 943 {
 944         u16 v;
 945
 946         if (virtio_config_val(vi->vdev, VIRTIO_NET_F_STATUS,
 947                               offsetof(struct virtio_net_config, status),
 948                               &v) < 0)
 949                 return;
 950
 951         /* Ignore unknown (future) status bits */
 952         v &= VIRTIO_NET_S_LINK_UP;
 953
 954         if (vi->status == v)
 955                 return;
 956
 957         vi->status = v;
 958
 959         if (vi->status & VIRTIO_NET_S_LINK_UP) {
 960                 netif_carrier_on(vi->dev);
 961                 netif_wake_queue(vi->dev);
 962         } else {
 963                 netif_carrier_off(vi->dev);
 964                 netif_stop_queue(vi->dev);
 965         }
 966 }
 967
 968 static void virtnet_config_changed(struct virtio_device *vdev)
 969 {
 970         struct virtnet_info *vi = vdev->priv;
 971
 972         virtnet_update_status(vi);
 973 }
 974
 975 static int virtnet_probe(struct virtio_device *vdev)
 976 {
 977         int err;
 978         struct net_device *dev;
 979         struct virtnet_info *vi;
 980         struct virtqueue *vqs[3];
 981         vq_callback_t *callbacks[] = { skb_recv_done, skb_xmit_done, NULL};
 982         const char *names[] = { "input", "output", "control" };
 983         int nvqs;
 984
 985         /* Allocate ourselves a network device with room for our info */
 986         dev = alloc_etherdev(sizeof(struct virtnet_info));
 987         if (!dev)
 988                 return -ENOMEM;
 989
 990         /* Set up network device as normal. */
 991         dev->priv_flags |= IFF_UNICAST_FLT;
 992         dev->netdev_ops = &virtnet_netdev;
 993         dev->features = NETIF_F_HIGHDMA;
 994
 995         SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
 996         SET_NETDEV_DEV(dev, &vdev->dev);
 997
 998         /* Do we support "hardware" checksums? */
 999         if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
1000                 /* This opens up the world of extra features. */
1001                 dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1002                 if (csum)
1003                         dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1004
1005                 if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
1006                         dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
1007                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
1008                 }
1009                 /* Individual feature bits: what can host handle? */
1010                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
1011                         dev->hw_features |= NETIF_F_TSO;
1012                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
1013                         dev->hw_features |= NETIF_F_TSO6;
1014                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
1015                         dev->hw_features |= NETIF_F_TSO_ECN;
1016                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
1017                         dev->hw_features |= NETIF_F_UFO;
1018
1019                 if (gso)
1020                         dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
1021                 /* (!csum && gso) case will be fixed by register_netdev() */
1022         }
1023
1024         /* Configuration may specify what MAC to use.  Otherwise random. */
1025         if (virtio_config_val_len(vdev, VIRTIO_NET_F_MAC,
1026                                   offsetof(struct virtio_net_config, mac),
1027                                   dev->dev_addr, dev->addr_len) < 0)
1028                 random_ether_addr(dev->dev_addr);
1029
1030         /* Set up our device-specific information */
1031         vi = netdev_priv(dev);
1032         netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
1033         vi->dev = dev;
1034         vi->vdev = vdev;
1035         vdev->priv = vi;
1036         vi->pages = NULL;
1037         vi->stats = alloc_percpu(struct virtnet_stats);
1038         err = -ENOMEM;
1039         if (vi->stats == NULL)
1040                 goto free;
1041
1042         INIT_DELAYED_WORK(&vi->refill, refill_work);
1043         sg_init_table(vi->rx_sg, ARRAY_SIZE(vi->rx_sg));
1044         sg_init_table(vi->tx_sg, ARRAY_SIZE(vi->tx_sg));
1045
1046         /* If we can receive ANY GSO packets, we must allocate large ones. */
1047         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1048             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
1049             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
1050                 vi->big_packets = true;
1051
1052         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
1053                 vi->mergeable_rx_bufs = true;
1054
1055         /* We expect two virtqueues, receive then send,
1056          * and optionally control. */
1057         nvqs = virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ? 3 : 2;
1058
1059         err = vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names);
1060         if (err)
1061                 goto free_stats;
1062
1063         vi->rvq = vqs[0];
1064         vi->svq = vqs[1];
1065
1066         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
1067                 vi->cvq = vqs[2];
1068
1069                 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1070                         dev->features |= NETIF_F_HW_VLAN_FILTER;
1071         }
1072
1073         err = register_netdev(dev);
1074         if (err) {
1075                 pr_debug("virtio_net: registering device failed\n");
1076                 goto free_vqs;
1077         }
1078
1079         /* Last of all, set up some receive buffers. */
1080         try_fill_recv(vi, GFP_KERNEL);
1081
1082         /* If we didn't even get one input buffer, we're useless. */
1083         if (vi->num == 0) {
1084                 err = -ENOMEM;
1085                 goto unregister;
1086         }
1087
1088         /* Assume link up if device can't report link status,
1089            otherwise get link status from config. */
1090         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1091                 netif_carrier_off(dev);
1092                 virtnet_update_status(vi);
1093         } else {
1094                 vi->status = VIRTIO_NET_S_LINK_UP;
1095                 netif_carrier_on(dev);
1096         }
1097
1098         pr_debug("virtnet: registered device %s\n", dev->name);
1099         return 0;
1100
1101 unregister:
1102         unregister_netdev(dev);
1103         cancel_delayed_work_sync(&vi->refill);
1104 free_vqs:
1105         vdev->config->del_vqs(vdev);
1106 free_stats:
1107         free_percpu(vi->stats);
1108 free:
1109         free_netdev(dev);
1110         return err;
1111 }
1112
1113 static void free_unused_bufs(struct virtnet_info *vi)
1114 {
1115         void *buf;
1116         while (1) {
1117                 buf = virtqueue_detach_unused_buf(vi->svq);
1118                 if (!buf)
1119                         break;
1120                 dev_kfree_skb(buf);
1121         }
1122         while (1) {
1123                 buf = virtqueue_detach_unused_buf(vi->rvq);
1124                 if (!buf)
1125                         break;
1126                 if (vi->mergeable_rx_bufs || vi->big_packets)
1127                         give_pages(vi, buf);
1128                 else
1129                         dev_kfree_skb(buf);
1130                 --vi->num;
1131         }
1132         BUG_ON(vi->num != 0);
1133 }
1134
1135 static void __devexit virtnet_remove(struct virtio_device *vdev)
1136 {
1137         struct virtnet_info *vi = vdev->priv;
1138
1139         /* Stop all the virtqueues. */
1140         vdev->config->reset(vdev);
1141
1142
1143         unregister_netdev(vi->dev);
1144         cancel_delayed_work_sync(&vi->refill);
1145
1146         /* Free unused buffers in both send and recv, if any. */
1147         free_unused_bufs(vi);
1148
1149         vdev->config->del_vqs(vi->vdev);
1150
1151         while (vi->pages)
1152                 __free_pages(get_a_page(vi, GFP_KERNEL), 0);
1153
1154         free_percpu(vi->stats);
1155         free_netdev(vi->dev);
1156 }
1157
1158 static struct virtio_device_id id_table[] = {
1159         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1160         { 0 },
1161 };
1162
1163 static unsigned int features[] = {
1164         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1165         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1166         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
1167         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1168         VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
1169         VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
1170         VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
1171 };
1172
1173 static struct virtio_driver virtio_net_driver = {
1174         .feature_table = features,
1175         .feature_table_size = ARRAY_SIZE(features),
1176         .driver.name =  KBUILD_MODNAME,
1177         .driver.owner = THIS_MODULE,
1178         .id_table =     id_table,
1179         .probe =        virtnet_probe,
1180         .remove =       __devexit_p(virtnet_remove),
1181         .config_changed = virtnet_config_changed,
1182 };
1183
1184 static int __init init(void)
1185 {
1186         return register_virtio_driver(&virtio_net_driver);
1187 }
1188
1189 static void __exit fini(void)
1190 {
1191         unregister_virtio_driver(&virtio_net_driver);
1192 }
1193 module_init(init);
1194 module_exit(fini);
1195
1196 MODULE_DEVICE_TABLE(virtio, id_table);
1197 MODULE_DESCRIPTION("Virtio network driver");
1198 MODULE_LICENSE("GPL");