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