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
  29 static int napi_weight = 128;
  30 module_param(napi_weight, int, 0444);
  31
  32 static int csum = 1, gso = 1;
  33 module_param(csum, bool, 0444);
  34 module_param(gso, bool, 0444);
  35
  36 /* FIXME: MTU in config. */
  37 #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
  38 #define GOOD_COPY_LEN   128
  39
  40 #define VIRTNET_SEND_COMMAND_SG_MAX    2
  41
  42 struct virtnet_info
  43 {
  44         struct virtio_device *vdev;
  45         struct virtqueue *rvq, *svq, *cvq;
  46         struct net_device *dev;
  47         struct napi_struct napi;
  48         unsigned int status;
  49
  50         /* Number of input buffers, and max we've ever had. */
  51         unsigned int num, max;
  52
  53         /* I like... big packets and I cannot lie! */
  54         bool big_packets;
  55
  56         /* Host will merge rx buffers for big packets (shake it! shake it!) */
  57         bool mergeable_rx_bufs;
  58
  59         /* 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
  66 struct skb_vnet_hdr {
  67         union {
  68                 struct virtio_net_hdr hdr;
  69                 struct virtio_net_hdr_mrg_rxbuf mhdr;
  70         };
  71         unsigned int num_sg;
  72 };
  73
  74 struct padded_vnet_hdr {
  75         struct virtio_net_hdr hdr;
  76         /*
  77          * virtio_net_hdr should be in a separated sg buffer because of a
  78          * QEMU bug, and data sg buffer shares same page with this header sg.
  79          * This padding makes next sg 16 byte aligned after virtio_net_hdr.
  80          */
  81         char padding[6];
  82 };
  83
  84 static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
  85 {
  86         return (struct skb_vnet_hdr *)skb->cb;
  87 }
  88
  89 /*
  90  * private is used to chain pages for big packets, put the whole
  91  * most recent used list in the beginning for reuse
  92  */
  93 static void give_pages(struct virtnet_info *vi, struct page *page)
  94 {
  95         struct page *end;
  96
  97         /* Find end of list, sew whole thing into vi->pages. */
  98         for (end = page; end->private; end = (struct page *)end->private);
  99         end->private = (unsigned long)vi->pages;
 100         vi->pages = page;
 101 }
 102
 103 static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
 104 {
 105         struct page *p = vi->pages;
 106
 107         if (p) {
 108                 vi->pages = (struct page *)p->private;
 109                 /* clear private here, it is used to chain pages */
 110                 p->private = 0;
 111         } else
 112                 p = alloc_page(gfp_mask);
 113         return p;
 114 }
 115
 116 static void skb_xmit_done(struct virtqueue *svq)
 117 {
 118         struct virtnet_info *vi = svq->vdev->priv;
 119
 120         /* Suppress further interrupts. */
 121         svq->vq_ops->disable_cb(svq);
 122
 123         /* We were probably waiting for more output buffers. */
 124         netif_wake_queue(vi->dev);
 125 }
 126
 127 static void set_skb_frag(struct sk_buff *skb, struct page *page,
 128                          unsigned int offset, unsigned int *len)
 129 {
 130         int i = skb_shinfo(skb)->nr_frags;
 131         skb_frag_t *f;
 132
 133         f = &skb_shinfo(skb)->frags[i];
 134         f->size = min((unsigned)PAGE_SIZE - offset, *len);
 135         f->page_offset = offset;
 136         f->page = page;
 137
 138         skb->data_len += f->size;
 139         skb->len += f->size;
 140         skb_shinfo(skb)->nr_frags++;
 141         *len -= f->size;
 142 }
 143
 144 static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 145                                    struct page *page, unsigned int len)
 146 {
 147         struct sk_buff *skb;
 148         struct skb_vnet_hdr *hdr;
 149         unsigned int copy, hdr_len, offset;
 150         char *p;
 151
 152         p = page_address(page);
 153
 154         /* copy small packet so we can reuse these pages for small data */
 155         skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
 156         if (unlikely(!skb))
 157                 return NULL;
 158
 159         hdr = skb_vnet_hdr(skb);
 160
 161         if (vi->mergeable_rx_bufs) {
 162                 hdr_len = sizeof hdr->mhdr;
 163                 offset = hdr_len;
 164         } else {
 165                 hdr_len = sizeof hdr->hdr;
 166                 offset = sizeof(struct padded_vnet_hdr);
 167         }
 168
 169         memcpy(hdr, p, hdr_len);
 170
 171         len -= hdr_len;
 172         p += offset;
 173
 174         copy = len;
 175         if (copy > skb_tailroom(skb))
 176                 copy = skb_tailroom(skb);
 177         memcpy(skb_put(skb, copy), p, copy);
 178
 179         len -= copy;
 180         offset += copy;
 181
 182         while (len) {
 183                 set_skb_frag(skb, page, offset, &len);
 184                 page = (struct page *)page->private;
 185                 offset = 0;
 186         }
 187
 188         if (page)
 189                 give_pages(vi, page);
 190
 191         return skb;
 192 }
 193
 194 static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb)
 195 {
 196         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 197         struct page *page;
 198         int num_buf, i, len;
 199
 200         num_buf = hdr->mhdr.num_buffers;
 201         while (--num_buf) {
 202                 i = skb_shinfo(skb)->nr_frags;
 203                 if (i >= MAX_SKB_FRAGS) {
 204                         pr_debug("%s: packet too long\n", skb->dev->name);
 205                         skb->dev->stats.rx_length_errors++;
 206                         return -EINVAL;
 207                 }
 208
 209                 page = vi->rvq->vq_ops->get_buf(vi->rvq, &len);
 210                 if (!page) {
 211                         pr_debug("%s: rx error: %d buffers missing\n",
 212                                  skb->dev->name, hdr->mhdr.num_buffers);
 213                         skb->dev->stats.rx_length_errors++;
 214                         return -EINVAL;
 215                 }
 216                 if (len > PAGE_SIZE)
 217                         len = PAGE_SIZE;
 218
 219                 set_skb_frag(skb, page, 0, &len);
 220
 221                 --vi->num;
 222         }
 223         return 0;
 224 }
 225
 226 static void receive_buf(struct net_device *dev, void *buf, unsigned int len)
 227 {
 228         struct virtnet_info *vi = netdev_priv(dev);
 229         struct sk_buff *skb;
 230         struct page *page;
 231         struct skb_vnet_hdr *hdr;
 232
 233         if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
 234                 pr_debug("%s: short packet %i\n", dev->name, len);
 235                 dev->stats.rx_length_errors++;
 236                 if (vi->mergeable_rx_bufs || vi->big_packets)
 237                         give_pages(vi, buf);
 238                 else
 239                         dev_kfree_skb(buf);
 240                 return;
 241         }
 242
 243         if (!vi->mergeable_rx_bufs && !vi->big_packets) {
 244                 skb = buf;
 245                 len -= sizeof(struct virtio_net_hdr);
 246                 skb_trim(skb, len);
 247         } else {
 248                 page = buf;
 249                 skb = page_to_skb(vi, page, len);
 250                 if (unlikely(!skb)) {
 251                         dev->stats.rx_dropped++;
 252                         give_pages(vi, page);
 253                         return;
 254                 }
 255                 if (vi->mergeable_rx_bufs)
 256                         if (receive_mergeable(vi, skb)) {
 257                                 dev_kfree_skb(skb);
 258                                 return;
 259                         }
 260         }
 261
 262         hdr = skb_vnet_hdr(skb);
 263         skb->truesize += skb->data_len;
 264         dev->stats.rx_bytes += skb->len;
 265         dev->stats.rx_packets++;
 266
 267         if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 268                 pr_debug("Needs csum!\n");
 269                 if (!skb_partial_csum_set(skb,
 270                                           hdr->hdr.csum_start,
 271                                           hdr->hdr.csum_offset))
 272                         goto frame_err;
 273         }
 274
 275         skb->protocol = eth_type_trans(skb, dev);
 276         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
 277                  ntohs(skb->protocol), skb->len, skb->pkt_type);
 278
 279         if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 280                 pr_debug("GSO!\n");
 281                 switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 282                 case VIRTIO_NET_HDR_GSO_TCPV4:
 283                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 284                         break;
 285                 case VIRTIO_NET_HDR_GSO_UDP:
 286                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 287                         break;
 288                 case VIRTIO_NET_HDR_GSO_TCPV6:
 289                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 290                         break;
 291                 default:
 292                         if (net_ratelimit())
 293                                 printk(KERN_WARNING "%s: bad gso type %u.\n",
 294                                        dev->name, hdr->hdr.gso_type);
 295                         goto frame_err;
 296                 }
 297
 298                 if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 299                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 300
 301                 skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
 302                 if (skb_shinfo(skb)->gso_size == 0) {
 303                         if (net_ratelimit())
 304                                 printk(KERN_WARNING "%s: zero gso size.\n",
 305                                        dev->name);
 306                         goto frame_err;
 307                 }
 308
 309                 /* Header must be checked, and gso_segs computed. */
 310                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 311                 skb_shinfo(skb)->gso_segs = 0;
 312         }
 313
 314         netif_receive_skb(skb);
 315         return;
 316
 317 frame_err:
 318         dev->stats.rx_frame_errors++;
 319         dev_kfree_skb(skb);
 320 }
 321
 322 static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp)
 323 {
 324         struct sk_buff *skb;
 325         struct skb_vnet_hdr *hdr;
 326         struct scatterlist sg[2];
 327         int err;
 328
 329         skb = netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN);
 330         if (unlikely(!skb))
 331                 return -ENOMEM;
 332
 333         skb_put(skb, MAX_PACKET_LEN);
 334
 335         hdr = skb_vnet_hdr(skb);
 336         sg_set_buf(sg, &hdr->hdr, sizeof hdr->hdr);
 337
 338         skb_to_sgvec(skb, sg + 1, 0, skb->len);
 339
 340         err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, 2, skb);
 341         if (err < 0)
 342                 dev_kfree_skb(skb);
 343
 344         return err;
 345 }
 346
 347 static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp)
 348 {
 349         struct scatterlist sg[MAX_SKB_FRAGS + 2];
 350         struct page *first, *list = NULL;
 351         char *p;
 352         int i, err, offset;
 353
 354         /* page in sg[MAX_SKB_FRAGS + 1] is list tail */
 355         for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
 356                 first = get_a_page(vi, gfp);
 357                 if (!first) {
 358                         if (list)
 359                                 give_pages(vi, list);
 360                         return -ENOMEM;
 361                 }
 362                 sg_set_buf(&sg[i], page_address(first), PAGE_SIZE);
 363
 364                 /* chain new page in list head to match sg */
 365                 first->private = (unsigned long)list;
 366                 list = first;
 367         }
 368
 369         first = get_a_page(vi, gfp);
 370         if (!first) {
 371                 give_pages(vi, list);
 372                 return -ENOMEM;
 373         }
 374         p = page_address(first);
 375
 376         /* sg[0], sg[1] share the same page */
 377         /* a separated sg[0] for  virtio_net_hdr only during to QEMU bug*/
 378         sg_set_buf(&sg[0], p, sizeof(struct virtio_net_hdr));
 379
 380         /* sg[1] for data packet, from offset */
 381         offset = sizeof(struct padded_vnet_hdr);
 382         sg_set_buf(&sg[1], p + offset, PAGE_SIZE - offset);
 383
 384         /* chain first in list head */
 385         first->private = (unsigned long)list;
 386         err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, MAX_SKB_FRAGS + 2,
 387                                        first);
 388         if (err < 0)
 389                 give_pages(vi, first);
 390
 391         return err;
 392 }
 393
 394 static int add_recvbuf_mergeable(struct virtnet_info *vi, gfp_t gfp)
 395 {
 396         struct page *page;
 397         struct scatterlist sg;
 398         int err;
 399
 400         page = get_a_page(vi, gfp);
 401         if (!page)
 402                 return -ENOMEM;
 403
 404         sg_init_one(&sg, page_address(page), PAGE_SIZE);
 405
 406         err = vi->rvq->vq_ops->add_buf(vi->rvq, &sg, 0, 1, page);
 407         if (err < 0)
 408                 give_pages(vi, page);
 409
 410         return err;
 411 }
 412
 413 /* Returns false if we couldn't fill entirely (OOM). */
 414 static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
 415 {
 416         int err;
 417         bool oom = false;
 418
 419         do {
 420                 if (vi->mergeable_rx_bufs)
 421                         err = add_recvbuf_mergeable(vi, gfp);
 422                 else if (vi->big_packets)
 423                         err = add_recvbuf_big(vi, gfp);
 424                 else
 425                         err = add_recvbuf_small(vi, gfp);
 426
 427                 if (err < 0) {
 428                         oom = true;
 429                         break;
 430                 }
 431                 ++vi->num;
 432         } while (err > 0);
 433         if (unlikely(vi->num > vi->max))
 434                 vi->max = vi->num;
 435         vi->rvq->vq_ops->kick(vi->rvq);
 436         return !oom;
 437 }
 438
 439 static void skb_recv_done(struct virtqueue *rvq)
 440 {
 441         struct virtnet_info *vi = rvq->vdev->priv;
 442         /* Schedule NAPI, Suppress further interrupts if successful. */
 443         if (napi_schedule_prep(&vi->napi)) {
 444                 rvq->vq_ops->disable_cb(rvq);
 445                 __napi_schedule(&vi->napi);
 446         }
 447 }
 448
 449 static void refill_work(struct work_struct *work)
 450 {
 451         struct virtnet_info *vi;
 452         bool still_empty;
 453
 454         vi = container_of(work, struct virtnet_info, refill.work);
 455         napi_disable(&vi->napi);
 456         still_empty = !try_fill_recv(vi, GFP_KERNEL);
 457         napi_enable(&vi->napi);
 458
 459         /* In theory, this can happen: if we don't get any buffers in
 460          * we will *never* try to fill again. */
 461         if (still_empty)
 462                 schedule_delayed_work(&vi->refill, HZ/2);
 463 }
 464
 465 static int virtnet_poll(struct napi_struct *napi, int budget)
 466 {
 467         struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
 468         void *buf;
 469         unsigned int len, received = 0;
 470
 471 again:
 472         while (received < budget &&
 473                (buf = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
 474                 receive_buf(vi->dev, buf, len);
 475                 --vi->num;
 476                 received++;
 477         }
 478
 479         if (vi->num < vi->max / 2) {
 480                 if (!try_fill_recv(vi, GFP_ATOMIC))
 481                         schedule_delayed_work(&vi->refill, 0);
 482         }
 483
 484         /* Out of packets? */
 485         if (received < budget) {
 486                 napi_complete(napi);
 487                 if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq)) &&
 488                     napi_schedule_prep(napi)) {
 489                         vi->rvq->vq_ops->disable_cb(vi->rvq);
 490                         __napi_schedule(napi);
 491                         goto again;
 492                 }
 493         }
 494
 495         return received;
 496 }
 497
 498 static unsigned int free_old_xmit_skbs(struct virtnet_info *vi)
 499 {
 500         struct sk_buff *skb;
 501         unsigned int len, tot_sgs = 0;
 502
 503         while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
 504                 pr_debug("Sent skb %p\n", skb);
 505                 vi->dev->stats.tx_bytes += skb->len;
 506                 vi->dev->stats.tx_packets++;
 507                 tot_sgs += skb_vnet_hdr(skb)->num_sg;
 508                 dev_kfree_skb_any(skb);
 509         }
 510         return tot_sgs;
 511 }
 512
 513 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
 514 {
 515         struct scatterlist sg[2+MAX_SKB_FRAGS];
 516         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 517         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 518
 519         sg_init_table(sg, 2+MAX_SKB_FRAGS);
 520
 521         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
 522
 523         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 524                 hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 525                 hdr->hdr.csum_start = skb->csum_start - skb_headroom(skb);
 526                 hdr->hdr.csum_offset = skb->csum_offset;
 527         } else {
 528                 hdr->hdr.flags = 0;
 529                 hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
 530         }
 531
 532         if (skb_is_gso(skb)) {
 533                 hdr->hdr.hdr_len = skb_headlen(skb);
 534                 hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
 535                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 536                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 537                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 538                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 539                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 540                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 541                 else
 542                         BUG();
 543                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
 544                         hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 545         } else {
 546                 hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 547                 hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
 548         }
 549
 550         hdr->mhdr.num_buffers = 0;
 551
 552         /* Encode metadata header at front. */
 553         if (vi->mergeable_rx_bufs)
 554                 sg_set_buf(sg, &hdr->mhdr, sizeof hdr->mhdr);
 555         else
 556                 sg_set_buf(sg, &hdr->hdr, sizeof hdr->hdr);
 557
 558         hdr->num_sg = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
 559         return vi->svq->vq_ops->add_buf(vi->svq, sg, hdr->num_sg, 0, skb);
 560 }
 561
 562 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 563 {
 564         struct virtnet_info *vi = netdev_priv(dev);
 565         int capacity;
 566
 567 again:
 568         /* Free up any pending old buffers before queueing new ones. */
 569         free_old_xmit_skbs(vi);
 570
 571         /* Try to transmit */
 572         capacity = xmit_skb(vi, skb);
 573
 574         /* This can happen with OOM and indirect buffers. */
 575         if (unlikely(capacity < 0)) {
 576                 netif_stop_queue(dev);
 577                 dev_warn(&dev->dev, "Unexpected full queue\n");
 578                 if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
 579                         vi->svq->vq_ops->disable_cb(vi->svq);
 580                         netif_start_queue(dev);
 581                         goto again;
 582                 }
 583                 return NETDEV_TX_BUSY;
 584         }
 585         vi->svq->vq_ops->kick(vi->svq);
 586
 587         /* Don't wait up for transmitted skbs to be freed. */
 588         skb_orphan(skb);
 589         nf_reset(skb);
 590
 591         /* Apparently nice girls don't return TX_BUSY; stop the queue
 592          * before it gets out of hand.  Naturally, this wastes entries. */
 593         if (capacity < 2+MAX_SKB_FRAGS) {
 594                 netif_stop_queue(dev);
 595                 if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
 596                         /* More just got used, free them then recheck. */
 597                         capacity += free_old_xmit_skbs(vi);
 598                         if (capacity >= 2+MAX_SKB_FRAGS) {
 599                                 netif_start_queue(dev);
 600                                 vi->svq->vq_ops->disable_cb(vi->svq);
 601                         }
 602                 }
 603         }
 604
 605         return NETDEV_TX_OK;
 606 }
 607
 608 static int virtnet_set_mac_address(struct net_device *dev, void *p)
 609 {
 610         struct virtnet_info *vi = netdev_priv(dev);
 611         struct virtio_device *vdev = vi->vdev;
 612         int ret;
 613
 614         ret = eth_mac_addr(dev, p);
 615         if (ret)
 616                 return ret;
 617
 618         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
 619                 vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
 620                                   dev->dev_addr, dev->addr_len);
 621
 622         return 0;
 623 }
 624
 625 #ifdef CONFIG_NET_POLL_CONTROLLER
 626 static void virtnet_netpoll(struct net_device *dev)
 627 {
 628         struct virtnet_info *vi = netdev_priv(dev);
 629
 630         napi_schedule(&vi->napi);
 631 }
 632 #endif
 633
 634 static int virtnet_open(struct net_device *dev)
 635 {
 636         struct virtnet_info *vi = netdev_priv(dev);
 637
 638         napi_enable(&vi->napi);
 639
 640         /* If all buffers were filled by other side before we napi_enabled, we
 641          * won't get another interrupt, so process any outstanding packets
 642          * now.  virtnet_poll wants re-enable the queue, so we disable here.
 643          * We synchronize against interrupts via NAPI_STATE_SCHED */
 644         if (napi_schedule_prep(&vi->napi)) {
 645                 vi->rvq->vq_ops->disable_cb(vi->rvq);
 646                 __napi_schedule(&vi->napi);
 647         }
 648         return 0;
 649 }
 650
 651 /*
 652  * Send command via the control virtqueue and check status.  Commands
 653  * supported by the hypervisor, as indicated by feature bits, should
 654  * never fail unless improperly formated.
 655  */
 656 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
 657                                  struct scatterlist *data, int out, int in)
 658 {
 659         struct scatterlist *s, sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
 660         struct virtio_net_ctrl_hdr ctrl;
 661         virtio_net_ctrl_ack status = ~0;
 662         unsigned int tmp;
 663         int i;
 664
 665         /* Caller should know better */
 666         BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ||
 667                 (out + in > VIRTNET_SEND_COMMAND_SG_MAX));
 668
 669         out++; /* Add header */
 670         in++; /* Add return status */
 671
 672         ctrl.class = class;
 673         ctrl.cmd = cmd;
 674
 675         sg_init_table(sg, out + in);
 676
 677         sg_set_buf(&sg[0], &ctrl, sizeof(ctrl));
 678         for_each_sg(data, s, out + in - 2, i)
 679                 sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
 680         sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
 681
 682         BUG_ON(vi->cvq->vq_ops->add_buf(vi->cvq, sg, out, in, vi) < 0);
 683
 684         vi->cvq->vq_ops->kick(vi->cvq);
 685
 686         /*
 687          * Spin for a response, the kick causes an ioport write, trapping
 688          * into the hypervisor, so the request should be handled immediately.
 689          */
 690         while (!vi->cvq->vq_ops->get_buf(vi->cvq, &tmp))
 691                 cpu_relax();
 692
 693         return status == VIRTIO_NET_OK;
 694 }
 695
 696 static int virtnet_close(struct net_device *dev)
 697 {
 698         struct virtnet_info *vi = netdev_priv(dev);
 699
 700         napi_disable(&vi->napi);
 701
 702         return 0;
 703 }
 704
 705 static int virtnet_set_tx_csum(struct net_device *dev, u32 data)
 706 {
 707         struct virtnet_info *vi = netdev_priv(dev);
 708         struct virtio_device *vdev = vi->vdev;
 709
 710         if (data && !virtio_has_feature(vdev, VIRTIO_NET_F_CSUM))
 711                 return -ENOSYS;
 712
 713         return ethtool_op_set_tx_hw_csum(dev, data);
 714 }
 715
 716 static void virtnet_set_rx_mode(struct net_device *dev)
 717 {
 718         struct virtnet_info *vi = netdev_priv(dev);
 719         struct scatterlist sg[2];
 720         u8 promisc, allmulti;
 721         struct virtio_net_ctrl_mac *mac_data;
 722         struct dev_addr_list *addr;
 723         struct netdev_hw_addr *ha;
 724         int uc_count;
 725         int mc_count;
 726         void *buf;
 727         int i;
 728
 729         /* We can't dynamicaly set ndo_set_rx_mode, so return gracefully */
 730         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
 731                 return;
 732
 733         promisc = ((dev->flags & IFF_PROMISC) != 0);
 734         allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
 735
 736         sg_init_one(sg, &promisc, sizeof(promisc));
 737
 738         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 739                                   VIRTIO_NET_CTRL_RX_PROMISC,
 740                                   sg, 1, 0))
 741                 dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
 742                          promisc ? "en" : "dis");
 743
 744         sg_init_one(sg, &allmulti, sizeof(allmulti));
 745
 746         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 747                                   VIRTIO_NET_CTRL_RX_ALLMULTI,
 748                                   sg, 1, 0))
 749                 dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
 750                          allmulti ? "en" : "dis");
 751
 752         uc_count = netdev_uc_count(dev);
 753         mc_count = netdev_mc_count(dev);
 754         /* MAC filter - use one buffer for both lists */
 755         buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
 756                       (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
 757         mac_data = buf;
 758         if (!buf) {
 759                 dev_warn(&dev->dev, "No memory for MAC address buffer\n");
 760                 return;
 761         }
 762
 763         sg_init_table(sg, 2);
 764
 765         /* Store the unicast list and count in the front of the buffer */
 766         mac_data->entries = uc_count;
 767         i = 0;
 768         netdev_for_each_uc_addr(ha, dev)
 769                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 770
 771         sg_set_buf(&sg[0], mac_data,
 772                    sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
 773
 774         /* multicast list and count fill the end */
 775         mac_data = (void *)&mac_data->macs[uc_count][0];
 776
 777         mac_data->entries = mc_count;
 778         addr = dev->mc_list;
 779         for (i = 0; i < mc_count; i++, addr = addr->next)
 780                 memcpy(&mac_data->macs[i][0], addr->da_addr, ETH_ALEN);
 781
 782         sg_set_buf(&sg[1], mac_data,
 783                    sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
 784
 785         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
 786                                   VIRTIO_NET_CTRL_MAC_TABLE_SET,
 787                                   sg, 2, 0))
 788                 dev_warn(&dev->dev, "Failed to set MAC fitler table.\n");
 789
 790         kfree(buf);
 791 }
 792
 793 static void virtnet_vlan_rx_add_vid(struct net_device *dev, u16 vid)
 794 {
 795         struct virtnet_info *vi = netdev_priv(dev);
 796         struct scatterlist sg;
 797
 798         sg_init_one(&sg, &vid, sizeof(vid));
 799
 800         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 801                                   VIRTIO_NET_CTRL_VLAN_ADD, &sg, 1, 0))
 802                 dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
 803 }
 804
 805 static void virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
 806 {
 807         struct virtnet_info *vi = netdev_priv(dev);
 808         struct scatterlist sg;
 809
 810         sg_init_one(&sg, &vid, sizeof(vid));
 811
 812         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 813                                   VIRTIO_NET_CTRL_VLAN_DEL, &sg, 1, 0))
 814                 dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
 815 }
 816
 817 static const struct ethtool_ops virtnet_ethtool_ops = {
 818         .set_tx_csum = virtnet_set_tx_csum,
 819         .set_sg = ethtool_op_set_sg,
 820         .set_tso = ethtool_op_set_tso,
 821         .set_ufo = ethtool_op_set_ufo,
 822         .get_link = ethtool_op_get_link,
 823 };
 824
 825 #define MIN_MTU 68
 826 #define MAX_MTU 65535
 827
 828 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
 829 {
 830         if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
 831                 return -EINVAL;
 832         dev->mtu = new_mtu;
 833         return 0;
 834 }
 835
 836 static const struct net_device_ops virtnet_netdev = {
 837         .ndo_open            = virtnet_open,
 838         .ndo_stop            = virtnet_close,
 839         .ndo_start_xmit      = start_xmit,
 840         .ndo_validate_addr   = eth_validate_addr,
 841         .ndo_set_mac_address = virtnet_set_mac_address,
 842         .ndo_set_rx_mode     = virtnet_set_rx_mode,
 843         .ndo_change_mtu      = virtnet_change_mtu,
 844         .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
 845         .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
 846 #ifdef CONFIG_NET_POLL_CONTROLLER
 847         .ndo_poll_controller = virtnet_netpoll,
 848 #endif
 849 };
 850
 851 static void virtnet_update_status(struct virtnet_info *vi)
 852 {
 853         u16 v;
 854
 855         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS))
 856                 return;
 857
 858         vi->vdev->config->get(vi->vdev,
 859                               offsetof(struct virtio_net_config, status),
 860                               &v, sizeof(v));
 861
 862         /* Ignore unknown (future) status bits */
 863         v &= VIRTIO_NET_S_LINK_UP;
 864
 865         if (vi->status == v)
 866                 return;
 867
 868         vi->status = v;
 869
 870         if (vi->status & VIRTIO_NET_S_LINK_UP) {
 871                 netif_carrier_on(vi->dev);
 872                 netif_wake_queue(vi->dev);
 873         } else {
 874                 netif_carrier_off(vi->dev);
 875                 netif_stop_queue(vi->dev);
 876         }
 877 }
 878
 879 static void virtnet_config_changed(struct virtio_device *vdev)
 880 {
 881         struct virtnet_info *vi = vdev->priv;
 882
 883         virtnet_update_status(vi);
 884 }
 885
 886 static int virtnet_probe(struct virtio_device *vdev)
 887 {
 888         int err;
 889         struct net_device *dev;
 890         struct virtnet_info *vi;
 891         struct virtqueue *vqs[3];
 892         vq_callback_t *callbacks[] = { skb_recv_done, skb_xmit_done, NULL};
 893         const char *names[] = { "input", "output", "control" };
 894         int nvqs;
 895
 896         /* Allocate ourselves a network device with room for our info */
 897         dev = alloc_etherdev(sizeof(struct virtnet_info));
 898         if (!dev)
 899                 return -ENOMEM;
 900
 901         /* Set up network device as normal. */
 902         dev->netdev_ops = &virtnet_netdev;
 903         dev->features = NETIF_F_HIGHDMA;
 904         SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
 905         SET_NETDEV_DEV(dev, &vdev->dev);
 906
 907         /* Do we support "hardware" checksums? */
 908         if (csum && virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
 909                 /* This opens up the world of extra features. */
 910                 dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
 911                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
 912                         dev->features |= NETIF_F_TSO | NETIF_F_UFO
 913                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
 914                 }
 915                 /* Individual feature bits: what can host handle? */
 916                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
 917                         dev->features |= NETIF_F_TSO;
 918                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
 919                         dev->features |= NETIF_F_TSO6;
 920                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
 921                         dev->features |= NETIF_F_TSO_ECN;
 922                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
 923                         dev->features |= NETIF_F_UFO;
 924         }
 925
 926         /* Configuration may specify what MAC to use.  Otherwise random. */
 927         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
 928                 vdev->config->get(vdev,
 929                                   offsetof(struct virtio_net_config, mac),
 930                                   dev->dev_addr, dev->addr_len);
 931         } else
 932                 random_ether_addr(dev->dev_addr);
 933
 934         /* Set up our device-specific information */
 935         vi = netdev_priv(dev);
 936         netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
 937         vi->dev = dev;
 938         vi->vdev = vdev;
 939         vdev->priv = vi;
 940         vi->pages = NULL;
 941         INIT_DELAYED_WORK(&vi->refill, refill_work);
 942
 943         /* If we can receive ANY GSO packets, we must allocate large ones. */
 944         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
 945             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
 946             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
 947                 vi->big_packets = true;
 948
 949         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
 950                 vi->mergeable_rx_bufs = true;
 951
 952         /* We expect two virtqueues, receive then send,
 953          * and optionally control. */
 954         nvqs = virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ? 3 : 2;
 955
 956         err = vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names);
 957         if (err)
 958                 goto free;
 959
 960         vi->rvq = vqs[0];
 961         vi->svq = vqs[1];
 962
 963         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
 964                 vi->cvq = vqs[2];
 965
 966                 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
 967                         dev->features |= NETIF_F_HW_VLAN_FILTER;
 968         }
 969
 970         err = register_netdev(dev);
 971         if (err) {
 972                 pr_debug("virtio_net: registering device failed\n");
 973                 goto free_vqs;
 974         }
 975
 976         /* Last of all, set up some receive buffers. */
 977         try_fill_recv(vi, GFP_KERNEL);
 978
 979         /* If we didn't even get one input buffer, we're useless. */
 980         if (vi->num == 0) {
 981                 err = -ENOMEM;
 982                 goto unregister;
 983         }
 984
 985         vi->status = VIRTIO_NET_S_LINK_UP;
 986         virtnet_update_status(vi);
 987         netif_carrier_on(dev);
 988
 989         pr_debug("virtnet: registered device %s\n", dev->name);
 990         return 0;
 991
 992 unregister:
 993         unregister_netdev(dev);
 994         cancel_delayed_work_sync(&vi->refill);
 995 free_vqs:
 996         vdev->config->del_vqs(vdev);
 997 free:
 998         free_netdev(dev);
 999         return err;
1000 }
1001
1002 static void free_unused_bufs(struct virtnet_info *vi)
1003 {
1004         void *buf;
1005         while (1) {
1006                 buf = vi->svq->vq_ops->detach_unused_buf(vi->svq);
1007                 if (!buf)
1008                         break;
1009                 dev_kfree_skb(buf);
1010         }
1011         while (1) {
1012                 buf = vi->rvq->vq_ops->detach_unused_buf(vi->rvq);
1013                 if (!buf)
1014                         break;
1015                 if (vi->mergeable_rx_bufs || vi->big_packets)
1016                         give_pages(vi, buf);
1017                 else
1018                         dev_kfree_skb(buf);
1019                 --vi->num;
1020         }
1021         BUG_ON(vi->num != 0);
1022 }
1023
1024 static void __devexit virtnet_remove(struct virtio_device *vdev)
1025 {
1026         struct virtnet_info *vi = vdev->priv;
1027
1028         /* Stop all the virtqueues. */
1029         vdev->config->reset(vdev);
1030
1031
1032         unregister_netdev(vi->dev);
1033         cancel_delayed_work_sync(&vi->refill);
1034
1035         /* Free unused buffers in both send and recv, if any. */
1036         free_unused_bufs(vi);
1037
1038         vdev->config->del_vqs(vi->vdev);
1039
1040         while (vi->pages)
1041                 __free_pages(get_a_page(vi, GFP_KERNEL), 0);
1042
1043         free_netdev(vi->dev);
1044 }
1045
1046 static struct virtio_device_id id_table[] = {
1047         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1048         { 0 },
1049 };
1050
1051 static unsigned int features[] = {
1052         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1053         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1054         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
1055         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1056         VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
1057         VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
1058         VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
1059 };
1060
1061 static struct virtio_driver virtio_net_driver = {
1062         .feature_table = features,
1063         .feature_table_size = ARRAY_SIZE(features),
1064         .driver.name =  KBUILD_MODNAME,
1065         .driver.owner = THIS_MODULE,
1066         .id_table =     id_table,
1067         .probe =        virtnet_probe,
1068         .remove =       __devexit_p(virtnet_remove),
1069         .config_changed = virtnet_config_changed,
1070 };
1071
1072 static int __init init(void)
1073 {
1074         return register_virtio_driver(&virtio_net_driver);
1075 }
1076
1077 static void __exit fini(void)
1078 {
1079         unregister_virtio_driver(&virtio_net_driver);
1080 }
1081 module_init(init);
1082 module_exit(fini);
1083
1084 MODULE_DEVICE_TABLE(virtio, id_table);
1085 MODULE_DESCRIPTION("Virtio network driver");
1086 MODULE_LICENSE("GPL");