drivers/net/virtio_net.c

   1 /* A network driver using virtio.
   2  *
   3  * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19 //#define DEBUG
  20 #include <linux/netdevice.h>
  21 #include <linux/etherdevice.h>
  22 #include <linux/ethtool.h>
  23 #include <linux/module.h>
  24 #include <linux/virtio.h>
  25 #include <linux/virtio_net.h>
  26 #include <linux/scatterlist.h>
  27 #include <linux/if_vlan.h>
  28 #include <linux/slab.h>
  29
  30 static int napi_weight = 128;
  31 module_param(napi_weight, int, 0444);
  32
  33 static int csum = 1, gso = 1;
  34 module_param(csum, bool, 0444);
  35 module_param(gso, bool, 0444);
  36
  37 /* FIXME: MTU in config. */
  38 #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
  39 #define GOOD_COPY_LEN   128
  40
  41 #define VIRTNET_SEND_COMMAND_SG_MAX    2
  42
  43 struct virtnet_info
  44 {
  45         struct virtio_device *vdev;
  46         struct virtqueue *rvq, *svq, *cvq;
  47         struct net_device *dev;
  48         struct napi_struct napi;
  49         unsigned int status;
  50
  51         /* Number of input buffers, and max we've ever had. */
  52         unsigned int num, max;
  53
  54         /* I like... big packets and I cannot lie! */
  55         bool big_packets;
  56
  57         /* Host will merge rx buffers for big packets (shake it! shake it!) */
  58         bool mergeable_rx_bufs;
  59
  60         /* Work struct for refilling if we run low on memory. */
  61         struct delayed_work refill;
  62
  63         /* Chain pages by the private ptr. */
  64         struct page *pages;
  65 };
  66
  67 struct skb_vnet_hdr {
  68         union {
  69                 struct virtio_net_hdr hdr;
  70                 struct virtio_net_hdr_mrg_rxbuf mhdr;
  71         };
  72         unsigned int num_sg;
  73 };
  74
  75 struct padded_vnet_hdr {
  76         struct virtio_net_hdr hdr;
  77         /*
  78          * virtio_net_hdr should be in a separated sg buffer because of a
  79          * QEMU bug, and data sg buffer shares same page with this header sg.
  80          * This padding makes next sg 16 byte aligned after virtio_net_hdr.
  81          */
  82         char padding[6];
  83 };
  84
  85 static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
  86 {
  87         return (struct skb_vnet_hdr *)skb->cb;
  88 }
  89
  90 /*
  91  * private is used to chain pages for big packets, put the whole
  92  * most recent used list in the beginning for reuse
  93  */
  94 static void give_pages(struct virtnet_info *vi, struct page *page)
  95 {
  96         struct page *end;
  97
  98         /* Find end of list, sew whole thing into vi->pages. */
  99         for (end = page; end->private; end = (struct page *)end->private);
 100         end->private = (unsigned long)vi->pages;
 101         vi->pages = page;
 102 }
 103
 104 static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
 105 {
 106         struct page *p = vi->pages;
 107
 108         if (p) {
 109                 vi->pages = (struct page *)p->private;
 110                 /* clear private here, it is used to chain pages */
 111                 p->private = 0;
 112         } else
 113                 p = alloc_page(gfp_mask);
 114         return p;
 115 }
 116
 117 static void skb_xmit_done(struct virtqueue *svq)
 118 {
 119         struct virtnet_info *vi = svq->vdev->priv;
 120
 121         /* Suppress further interrupts. */
 122         svq->vq_ops->disable_cb(svq);
 123
 124         /* We were probably waiting for more output buffers. */
 125         netif_wake_queue(vi->dev);
 126 }
 127
 128 static void set_skb_frag(struct sk_buff *skb, struct page *page,
 129                          unsigned int offset, unsigned int *len)
 130 {
 131         int i = skb_shinfo(skb)->nr_frags;
 132         skb_frag_t *f;
 133
 134         f = &skb_shinfo(skb)->frags[i];
 135         f->size = min((unsigned)PAGE_SIZE - offset, *len);
 136         f->page_offset = offset;
 137         f->page = page;
 138
 139         skb->data_len += f->size;
 140         skb->len += f->size;
 141         skb_shinfo(skb)->nr_frags++;
 142         *len -= f->size;
 143 }
 144
 145 static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 146                                    struct page *page, unsigned int len)
 147 {
 148         struct sk_buff *skb;
 149         struct skb_vnet_hdr *hdr;
 150         unsigned int copy, hdr_len, offset;
 151         char *p;
 152
 153         p = page_address(page);
 154
 155         /* copy small packet so we can reuse these pages for small data */
 156         skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
 157         if (unlikely(!skb))
 158                 return NULL;
 159
 160         hdr = skb_vnet_hdr(skb);
 161
 162         if (vi->mergeable_rx_bufs) {
 163                 hdr_len = sizeof hdr->mhdr;
 164                 offset = hdr_len;
 165         } else {
 166                 hdr_len = sizeof hdr->hdr;
 167                 offset = sizeof(struct padded_vnet_hdr);
 168         }
 169
 170         memcpy(hdr, p, hdr_len);
 171
 172         len -= hdr_len;
 173         p += offset;
 174
 175         copy = len;
 176         if (copy > skb_tailroom(skb))
 177                 copy = skb_tailroom(skb);
 178         memcpy(skb_put(skb, copy), p, copy);
 179
 180         len -= copy;
 181         offset += copy;
 182
 183         while (len) {
 184                 set_skb_frag(skb, page, offset, &len);
 185                 page = (struct page *)page->private;
 186                 offset = 0;
 187         }
 188
 189         if (page)
 190                 give_pages(vi, page);
 191
 192         return skb;
 193 }
 194
 195 static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb)
 196 {
 197         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 198         struct page *page;
 199         int num_buf, i, len;
 200
 201         num_buf = hdr->mhdr.num_buffers;
 202         while (--num_buf) {
 203                 i = skb_shinfo(skb)->nr_frags;
 204                 if (i >= MAX_SKB_FRAGS) {
 205                         pr_debug("%s: packet too long\n", skb->dev->name);
 206                         skb->dev->stats.rx_length_errors++;
 207                         return -EINVAL;
 208                 }
 209
 210                 page = vi->rvq->vq_ops->get_buf(vi->rvq, &len);
 211                 if (!page) {
 212                         pr_debug("%s: rx error: %d buffers missing\n",
 213                                  skb->dev->name, hdr->mhdr.num_buffers);
 214                         skb->dev->stats.rx_length_errors++;
 215                         return -EINVAL;
 216                 }
 217                 if (len > PAGE_SIZE)
 218                         len = PAGE_SIZE;
 219
 220                 set_skb_frag(skb, page, 0, &len);
 221
 222                 --vi->num;
 223         }
 224         return 0;
 225 }
 226
 227 static void receive_buf(struct net_device *dev, void *buf, unsigned int len)
 228 {
 229         struct virtnet_info *vi = netdev_priv(dev);
 230         struct sk_buff *skb;
 231         struct page *page;
 232         struct skb_vnet_hdr *hdr;
 233
 234         if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
 235                 pr_debug("%s: short packet %i\n", dev->name, len);
 236                 dev->stats.rx_length_errors++;
 237                 if (vi->mergeable_rx_bufs || vi->big_packets)
 238                         give_pages(vi, buf);
 239                 else
 240                         dev_kfree_skb(buf);
 241                 return;
 242         }
 243
 244         if (!vi->mergeable_rx_bufs && !vi->big_packets) {
 245                 skb = buf;
 246                 len -= sizeof(struct virtio_net_hdr);
 247                 skb_trim(skb, len);
 248         } else {
 249                 page = buf;
 250                 skb = page_to_skb(vi, page, len);
 251                 if (unlikely(!skb)) {
 252                         dev->stats.rx_dropped++;
 253                         give_pages(vi, page);
 254                         return;
 255                 }
 256                 if (vi->mergeable_rx_bufs)
 257                         if (receive_mergeable(vi, skb)) {
 258                                 dev_kfree_skb(skb);
 259                                 return;
 260                         }
 261         }
 262
 263         hdr = skb_vnet_hdr(skb);
 264         skb->truesize += skb->data_len;
 265         dev->stats.rx_bytes += skb->len;
 266         dev->stats.rx_packets++;
 267
 268         if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 269                 pr_debug("Needs csum!\n");
 270                 if (!skb_partial_csum_set(skb,
 271                                           hdr->hdr.csum_start,
 272                                           hdr->hdr.csum_offset))
 273                         goto frame_err;
 274         }
 275
 276         skb->protocol = eth_type_trans(skb, dev);
 277         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
 278                  ntohs(skb->protocol), skb->len, skb->pkt_type);
 279
 280         if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 281                 pr_debug("GSO!\n");
 282                 switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 283                 case VIRTIO_NET_HDR_GSO_TCPV4:
 284                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 285                         break;
 286                 case VIRTIO_NET_HDR_GSO_UDP:
 287                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 288                         break;
 289                 case VIRTIO_NET_HDR_GSO_TCPV6:
 290                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 291                         break;
 292                 default:
 293                         if (net_ratelimit())
 294                                 printk(KERN_WARNING "%s: bad gso type %u.\n",
 295                                        dev->name, hdr->hdr.gso_type);
 296                         goto frame_err;
 297                 }
 298
 299                 if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 300                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 301
 302                 skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
 303                 if (skb_shinfo(skb)->gso_size == 0) {
 304                         if (net_ratelimit())
 305                                 printk(KERN_WARNING "%s: zero gso size.\n",
 306                                        dev->name);
 307                         goto frame_err;
 308                 }
 309
 310                 /* Header must be checked, and gso_segs computed. */
 311                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 312                 skb_shinfo(skb)->gso_segs = 0;
 313         }
 314
 315         netif_receive_skb(skb);
 316         return;
 317
 318 frame_err:
 319         dev->stats.rx_frame_errors++;
 320         dev_kfree_skb(skb);
 321 }
 322
 323 static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp)
 324 {
 325         struct sk_buff *skb;
 326         struct skb_vnet_hdr *hdr;
 327         struct scatterlist sg[2];
 328         int err;
 329
 330         sg_init_table(sg, 2);
 331         skb = netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN);
 332         if (unlikely(!skb))
 333                 return -ENOMEM;
 334
 335         skb_put(skb, MAX_PACKET_LEN);
 336
 337         hdr = skb_vnet_hdr(skb);
 338         sg_set_buf(sg, &hdr->hdr, sizeof hdr->hdr);
 339
 340         skb_to_sgvec(skb, sg + 1, 0, skb->len);
 341
 342         err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, 2, skb);
 343         if (err < 0)
 344                 dev_kfree_skb(skb);
 345
 346         return err;
 347 }
 348
 349 static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp)
 350 {
 351         struct scatterlist sg[MAX_SKB_FRAGS + 2];
 352         struct page *first, *list = NULL;
 353         char *p;
 354         int i, err, offset;
 355
 356         sg_init_table(sg, MAX_SKB_FRAGS + 2);
 357         /* page in sg[MAX_SKB_FRAGS + 1] is list tail */
 358         for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
 359                 first = get_a_page(vi, gfp);
 360                 if (!first) {
 361                         if (list)
 362                                 give_pages(vi, list);
 363                         return -ENOMEM;
 364                 }
 365                 sg_set_buf(&sg[i], page_address(first), PAGE_SIZE);
 366
 367                 /* chain new page in list head to match sg */
 368                 first->private = (unsigned long)list;
 369                 list = first;
 370         }
 371
 372         first = get_a_page(vi, gfp);
 373         if (!first) {
 374                 give_pages(vi, list);
 375                 return -ENOMEM;
 376         }
 377         p = page_address(first);
 378
 379         /* sg[0], sg[1] share the same page */
 380         /* a separated sg[0] for  virtio_net_hdr only during to QEMU bug*/
 381         sg_set_buf(&sg[0], p, sizeof(struct virtio_net_hdr));
 382
 383         /* sg[1] for data packet, from offset */
 384         offset = sizeof(struct padded_vnet_hdr);
 385         sg_set_buf(&sg[1], p + offset, PAGE_SIZE - offset);
 386
 387         /* chain first in list head */
 388         first->private = (unsigned long)list;
 389         err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, MAX_SKB_FRAGS + 2,
 390                                        first);
 391         if (err < 0)
 392                 give_pages(vi, first);
 393
 394         return err;
 395 }
 396
 397 static int add_recvbuf_mergeable(struct virtnet_info *vi, gfp_t gfp)
 398 {
 399         struct page *page;
 400         struct scatterlist sg;
 401         int err;
 402
 403         page = get_a_page(vi, gfp);
 404         if (!page)
 405                 return -ENOMEM;
 406
 407         sg_init_one(&sg, page_address(page), PAGE_SIZE);
 408
 409         err = vi->rvq->vq_ops->add_buf(vi->rvq, &sg, 0, 1, page);
 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 = false;
 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                 if (err < 0) {
 431                         oom = true;
 432                         break;
 433                 }
 434                 ++vi->num;
 435         } while (err > 0);
 436         if (unlikely(vi->num > vi->max))
 437                 vi->max = vi->num;
 438         vi->rvq->vq_ops->kick(vi->rvq);
 439         return !oom;
 440 }
 441
 442 static void skb_recv_done(struct virtqueue *rvq)
 443 {
 444         struct virtnet_info *vi = rvq->vdev->priv;
 445         /* Schedule NAPI, Suppress further interrupts if successful. */
 446         if (napi_schedule_prep(&vi->napi)) {
 447                 rvq->vq_ops->disable_cb(rvq);
 448                 __napi_schedule(&vi->napi);
 449         }
 450 }
 451
 452 static void refill_work(struct work_struct *work)
 453 {
 454         struct virtnet_info *vi;
 455         bool still_empty;
 456
 457         vi = container_of(work, struct virtnet_info, refill.work);
 458         napi_disable(&vi->napi);
 459         still_empty = !try_fill_recv(vi, GFP_KERNEL);
 460         napi_enable(&vi->napi);
 461
 462         /* In theory, this can happen: if we don't get any buffers in
 463          * we will *never* try to fill again. */
 464         if (still_empty)
 465                 schedule_delayed_work(&vi->refill, HZ/2);
 466 }
 467
 468 static int virtnet_poll(struct napi_struct *napi, int budget)
 469 {
 470         struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
 471         void *buf;
 472         unsigned int len, received = 0;
 473
 474 again:
 475         while (received < budget &&
 476                (buf = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
 477                 receive_buf(vi->dev, buf, len);
 478                 --vi->num;
 479                 received++;
 480         }
 481
 482         if (vi->num < vi->max / 2) {
 483                 if (!try_fill_recv(vi, GFP_ATOMIC))
 484                         schedule_delayed_work(&vi->refill, 0);
 485         }
 486
 487         /* Out of packets? */
 488         if (received < budget) {
 489                 napi_complete(napi);
 490                 if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq)) &&
 491                     napi_schedule_prep(napi)) {
 492                         vi->rvq->vq_ops->disable_cb(vi->rvq);
 493                         __napi_schedule(napi);
 494                         goto again;
 495                 }
 496         }
 497
 498         return received;
 499 }
 500
 501 static unsigned int free_old_xmit_skbs(struct virtnet_info *vi)
 502 {
 503         struct sk_buff *skb;
 504         unsigned int len, tot_sgs = 0;
 505
 506         while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
 507                 pr_debug("Sent skb %p\n", skb);
 508                 vi->dev->stats.tx_bytes += skb->len;
 509                 vi->dev->stats.tx_packets++;
 510                 tot_sgs += skb_vnet_hdr(skb)->num_sg;
 511                 dev_kfree_skb_any(skb);
 512         }
 513         return tot_sgs;
 514 }
 515
 516 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
 517 {
 518         struct scatterlist sg[2+MAX_SKB_FRAGS];
 519         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 520         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 521
 522         sg_init_table(sg, 2+MAX_SKB_FRAGS);
 523
 524         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
 525
 526         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 527                 hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 528                 hdr->hdr.csum_start = skb->csum_start - skb_headroom(skb);
 529                 hdr->hdr.csum_offset = skb->csum_offset;
 530         } else {
 531                 hdr->hdr.flags = 0;
 532                 hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
 533         }
 534
 535         if (skb_is_gso(skb)) {
 536                 hdr->hdr.hdr_len = skb_headlen(skb);
 537                 hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
 538                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 539                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 540                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 541                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 542                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 543                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 544                 else
 545                         BUG();
 546                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
 547                         hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 548         } else {
 549                 hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 550                 hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
 551         }
 552
 553         hdr->mhdr.num_buffers = 0;
 554
 555         /* Encode metadata header at front. */
 556         if (vi->mergeable_rx_bufs)
 557                 sg_set_buf(sg, &hdr->mhdr, sizeof hdr->mhdr);
 558         else
 559                 sg_set_buf(sg, &hdr->hdr, sizeof hdr->hdr);
 560
 561         hdr->num_sg = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
 562         return vi->svq->vq_ops->add_buf(vi->svq, sg, hdr->num_sg, 0, skb);
 563 }
 564
 565 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 566 {
 567         struct virtnet_info *vi = netdev_priv(dev);
 568         int capacity;
 569
 570 again:
 571         /* Free up any pending old buffers before queueing new ones. */
 572         free_old_xmit_skbs(vi);
 573
 574         /* Try to transmit */
 575         capacity = xmit_skb(vi, skb);
 576
 577         /* This can happen with OOM and indirect buffers. */
 578         if (unlikely(capacity < 0)) {
 579                 netif_stop_queue(dev);
 580                 dev_warn(&dev->dev, "Unexpected full queue\n");
 581                 if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
 582                         vi->svq->vq_ops->disable_cb(vi->svq);
 583                         netif_start_queue(dev);
 584                         goto again;
 585                 }
 586                 return NETDEV_TX_BUSY;
 587         }
 588         vi->svq->vq_ops->kick(vi->svq);
 589
 590         /* Don't wait up for transmitted skbs to be freed. */
 591         skb_orphan(skb);
 592         nf_reset(skb);
 593
 594         /* Apparently nice girls don't return TX_BUSY; stop the queue
 595          * before it gets out of hand.  Naturally, this wastes entries. */
 596         if (capacity < 2+MAX_SKB_FRAGS) {
 597                 netif_stop_queue(dev);
 598                 if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
 599                         /* More just got used, free them then recheck. */
 600                         capacity += free_old_xmit_skbs(vi);
 601                         if (capacity >= 2+MAX_SKB_FRAGS) {
 602                                 netif_start_queue(dev);
 603                                 vi->svq->vq_ops->disable_cb(vi->svq);
 604                         }
 605                 }
 606         }
 607
 608         return NETDEV_TX_OK;
 609 }
 610
 611 static int virtnet_set_mac_address(struct net_device *dev, void *p)
 612 {
 613         struct virtnet_info *vi = netdev_priv(dev);
 614         struct virtio_device *vdev = vi->vdev;
 615         int ret;
 616
 617         ret = eth_mac_addr(dev, p);
 618         if (ret)
 619                 return ret;
 620
 621         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
 622                 vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
 623                                   dev->dev_addr, dev->addr_len);
 624
 625         return 0;
 626 }
 627
 628 #ifdef CONFIG_NET_POLL_CONTROLLER
 629 static void virtnet_netpoll(struct net_device *dev)
 630 {
 631         struct virtnet_info *vi = netdev_priv(dev);
 632
 633         napi_schedule(&vi->napi);
 634 }
 635 #endif
 636
 637 static int virtnet_open(struct net_device *dev)
 638 {
 639         struct virtnet_info *vi = netdev_priv(dev);
 640
 641         napi_enable(&vi->napi);
 642
 643         /* If all buffers were filled by other side before we napi_enabled, we
 644          * won't get another interrupt, so process any outstanding packets
 645          * now.  virtnet_poll wants re-enable the queue, so we disable here.
 646          * We synchronize against interrupts via NAPI_STATE_SCHED */
 647         if (napi_schedule_prep(&vi->napi)) {
 648                 vi->rvq->vq_ops->disable_cb(vi->rvq);
 649                 __napi_schedule(&vi->napi);
 650         }
 651         return 0;
 652 }
 653
 654 /*
 655  * Send command via the control virtqueue and check status.  Commands
 656  * supported by the hypervisor, as indicated by feature bits, should
 657  * never fail unless improperly formated.
 658  */
 659 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
 660                                  struct scatterlist *data, int out, int in)
 661 {
 662         struct scatterlist *s, sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
 663         struct virtio_net_ctrl_hdr ctrl;
 664         virtio_net_ctrl_ack status = ~0;
 665         unsigned int tmp;
 666         int i;
 667
 668         /* Caller should know better */
 669         BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ||
 670                 (out + in > VIRTNET_SEND_COMMAND_SG_MAX));
 671
 672         out++; /* Add header */
 673         in++; /* Add return status */
 674
 675         ctrl.class = class;
 676         ctrl.cmd = cmd;
 677
 678         sg_init_table(sg, out + in);
 679
 680         sg_set_buf(&sg[0], &ctrl, sizeof(ctrl));
 681         for_each_sg(data, s, out + in - 2, i)
 682                 sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
 683         sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
 684
 685         BUG_ON(vi->cvq->vq_ops->add_buf(vi->cvq, sg, out, in, vi) < 0);
 686
 687         vi->cvq->vq_ops->kick(vi->cvq);
 688
 689         /*
 690          * Spin for a response, the kick causes an ioport write, trapping
 691          * into the hypervisor, so the request should be handled immediately.
 692          */
 693         while (!vi->cvq->vq_ops->get_buf(vi->cvq, &tmp))
 694                 cpu_relax();
 695
 696         return status == VIRTIO_NET_OK;
 697 }
 698
 699 static int virtnet_close(struct net_device *dev)
 700 {
 701         struct virtnet_info *vi = netdev_priv(dev);
 702
 703         napi_disable(&vi->napi);
 704
 705         return 0;
 706 }
 707
 708 static int virtnet_set_tx_csum(struct net_device *dev, u32 data)
 709 {
 710         struct virtnet_info *vi = netdev_priv(dev);
 711         struct virtio_device *vdev = vi->vdev;
 712
 713         if (data && !virtio_has_feature(vdev, VIRTIO_NET_F_CSUM))
 714                 return -ENOSYS;
 715
 716         return ethtool_op_set_tx_hw_csum(dev, data);
 717 }
 718
 719 static void virtnet_set_rx_mode(struct net_device *dev)
 720 {
 721         struct virtnet_info *vi = netdev_priv(dev);
 722         struct scatterlist sg[2];
 723         u8 promisc, allmulti;
 724         struct virtio_net_ctrl_mac *mac_data;
 725         struct dev_addr_list *addr;
 726         struct netdev_hw_addr *ha;
 727         int uc_count;
 728         int mc_count;
 729         void *buf;
 730         int i;
 731
 732         /* We can't dynamicaly set ndo_set_rx_mode, so return gracefully */
 733         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
 734                 return;
 735
 736         promisc = ((dev->flags & IFF_PROMISC) != 0);
 737         allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
 738
 739         sg_init_one(sg, &promisc, sizeof(promisc));
 740
 741         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 742                                   VIRTIO_NET_CTRL_RX_PROMISC,
 743                                   sg, 1, 0))
 744                 dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
 745                          promisc ? "en" : "dis");
 746
 747         sg_init_one(sg, &allmulti, sizeof(allmulti));
 748
 749         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 750                                   VIRTIO_NET_CTRL_RX_ALLMULTI,
 751                                   sg, 1, 0))
 752                 dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
 753                          allmulti ? "en" : "dis");
 754
 755         uc_count = netdev_uc_count(dev);
 756         mc_count = netdev_mc_count(dev);
 757         /* MAC filter - use one buffer for both lists */
 758         buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
 759                       (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
 760         mac_data = buf;
 761         if (!buf) {
 762                 dev_warn(&dev->dev, "No memory for MAC address buffer\n");
 763                 return;
 764         }
 765
 766         sg_init_table(sg, 2);
 767
 768         /* Store the unicast list and count in the front of the buffer */
 769         mac_data->entries = uc_count;
 770         i = 0;
 771         netdev_for_each_uc_addr(ha, dev)
 772                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 773
 774         sg_set_buf(&sg[0], mac_data,
 775                    sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
 776
 777         /* multicast list and count fill the end */
 778         mac_data = (void *)&mac_data->macs[uc_count][0];
 779
 780         mac_data->entries = mc_count;
 781         i = 0;
 782         netdev_for_each_mc_addr(addr, dev)
 783                 memcpy(&mac_data->macs[i++][0], addr->da_addr, ETH_ALEN);
 784
 785         sg_set_buf(&sg[1], mac_data,
 786                    sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
 787
 788         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
 789                                   VIRTIO_NET_CTRL_MAC_TABLE_SET,
 790                                   sg, 2, 0))
 791                 dev_warn(&dev->dev, "Failed to set MAC fitler table.\n");
 792
 793         kfree(buf);
 794 }
 795
 796 static void virtnet_vlan_rx_add_vid(struct net_device *dev, u16 vid)
 797 {
 798         struct virtnet_info *vi = netdev_priv(dev);
 799         struct scatterlist sg;
 800
 801         sg_init_one(&sg, &vid, sizeof(vid));
 802
 803         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 804                                   VIRTIO_NET_CTRL_VLAN_ADD, &sg, 1, 0))
 805                 dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
 806 }
 807
 808 static void virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
 809 {
 810         struct virtnet_info *vi = netdev_priv(dev);
 811         struct scatterlist sg;
 812
 813         sg_init_one(&sg, &vid, sizeof(vid));
 814
 815         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 816                                   VIRTIO_NET_CTRL_VLAN_DEL, &sg, 1, 0))
 817                 dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
 818 }
 819
 820 static const struct ethtool_ops virtnet_ethtool_ops = {
 821         .set_tx_csum = virtnet_set_tx_csum,
 822         .set_sg = ethtool_op_set_sg,
 823         .set_tso = ethtool_op_set_tso,
 824         .set_ufo = ethtool_op_set_ufo,
 825         .get_link = ethtool_op_get_link,
 826 };
 827
 828 #define MIN_MTU 68
 829 #define MAX_MTU 65535
 830
 831 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
 832 {
 833         if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
 834                 return -EINVAL;
 835         dev->mtu = new_mtu;
 836         return 0;
 837 }
 838
 839 static const struct net_device_ops virtnet_netdev = {
 840         .ndo_open            = virtnet_open,
 841         .ndo_stop            = virtnet_close,
 842         .ndo_start_xmit      = start_xmit,
 843         .ndo_validate_addr   = eth_validate_addr,
 844         .ndo_set_mac_address = virtnet_set_mac_address,
 845         .ndo_set_rx_mode     = virtnet_set_rx_mode,
 846         .ndo_change_mtu      = virtnet_change_mtu,
 847         .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
 848         .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
 849 #ifdef CONFIG_NET_POLL_CONTROLLER
 850         .ndo_poll_controller = virtnet_netpoll,
 851 #endif
 852 };
 853
 854 static void virtnet_update_status(struct virtnet_info *vi)
 855 {
 856         u16 v;
 857
 858         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS))
 859                 return;
 860
 861         vi->vdev->config->get(vi->vdev,
 862                               offsetof(struct virtio_net_config, status),
 863                               &v, sizeof(v));
 864
 865         /* Ignore unknown (future) status bits */
 866         v &= VIRTIO_NET_S_LINK_UP;
 867
 868         if (vi->status == v)
 869                 return;
 870
 871         vi->status = v;
 872
 873         if (vi->status & VIRTIO_NET_S_LINK_UP) {
 874                 netif_carrier_on(vi->dev);
 875                 netif_wake_queue(vi->dev);
 876         } else {
 877                 netif_carrier_off(vi->dev);
 878                 netif_stop_queue(vi->dev);
 879         }
 880 }
 881
 882 static void virtnet_config_changed(struct virtio_device *vdev)
 883 {
 884         struct virtnet_info *vi = vdev->priv;
 885
 886         virtnet_update_status(vi);
 887 }
 888
 889 static int virtnet_probe(struct virtio_device *vdev)
 890 {
 891         int err;
 892         struct net_device *dev;
 893         struct virtnet_info *vi;
 894         struct virtqueue *vqs[3];
 895         vq_callback_t *callbacks[] = { skb_recv_done, skb_xmit_done, NULL};
 896         const char *names[] = { "input", "output", "control" };
 897         int nvqs;
 898
 899         /* Allocate ourselves a network device with room for our info */
 900         dev = alloc_etherdev(sizeof(struct virtnet_info));
 901         if (!dev)
 902                 return -ENOMEM;
 903
 904         /* Set up network device as normal. */
 905         dev->netdev_ops = &virtnet_netdev;
 906         dev->features = NETIF_F_HIGHDMA;
 907         SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
 908         SET_NETDEV_DEV(dev, &vdev->dev);
 909
 910         /* Do we support "hardware" checksums? */
 911         if (csum && virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
 912                 /* This opens up the world of extra features. */
 913                 dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
 914                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
 915                         dev->features |= NETIF_F_TSO | NETIF_F_UFO
 916                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
 917                 }
 918                 /* Individual feature bits: what can host handle? */
 919                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
 920                         dev->features |= NETIF_F_TSO;
 921                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
 922                         dev->features |= NETIF_F_TSO6;
 923                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
 924                         dev->features |= NETIF_F_TSO_ECN;
 925                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
 926                         dev->features |= NETIF_F_UFO;
 927         }
 928
 929         /* Configuration may specify what MAC to use.  Otherwise random. */
 930         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
 931                 vdev->config->get(vdev,
 932                                   offsetof(struct virtio_net_config, mac),
 933                                   dev->dev_addr, dev->addr_len);
 934         } else
 935                 random_ether_addr(dev->dev_addr);
 936
 937         /* Set up our device-specific information */
 938         vi = netdev_priv(dev);
 939         netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
 940         vi->dev = dev;
 941         vi->vdev = vdev;
 942         vdev->priv = vi;
 943         vi->pages = NULL;
 944         INIT_DELAYED_WORK(&vi->refill, refill_work);
 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         vi->status = VIRTIO_NET_S_LINK_UP;
 989         virtnet_update_status(vi);
 990         netif_carrier_on(dev);
 991
 992         pr_debug("virtnet: registered device %s\n", dev->name);
 993         return 0;
 994
 995 unregister:
 996         unregister_netdev(dev);
 997         cancel_delayed_work_sync(&vi->refill);
 998 free_vqs:
 999         vdev->config->del_vqs(vdev);
1000 free:
1001         free_netdev(dev);
1002         return err;
1003 }
1004
1005 static void free_unused_bufs(struct virtnet_info *vi)
1006 {
1007         void *buf;
1008         while (1) {
1009                 buf = vi->svq->vq_ops->detach_unused_buf(vi->svq);
1010                 if (!buf)
1011                         break;
1012                 dev_kfree_skb(buf);
1013         }
1014         while (1) {
1015                 buf = vi->rvq->vq_ops->detach_unused_buf(vi->rvq);
1016                 if (!buf)
1017                         break;
1018                 if (vi->mergeable_rx_bufs || vi->big_packets)
1019                         give_pages(vi, buf);
1020                 else
1021                         dev_kfree_skb(buf);
1022                 --vi->num;
1023         }
1024         BUG_ON(vi->num != 0);
1025 }
1026
1027 static void __devexit virtnet_remove(struct virtio_device *vdev)
1028 {
1029         struct virtnet_info *vi = vdev->priv;
1030
1031         /* Stop all the virtqueues. */
1032         vdev->config->reset(vdev);
1033
1034
1035         unregister_netdev(vi->dev);
1036         cancel_delayed_work_sync(&vi->refill);
1037
1038         /* Free unused buffers in both send and recv, if any. */
1039         free_unused_bufs(vi);
1040
1041         vdev->config->del_vqs(vi->vdev);
1042
1043         while (vi->pages)
1044                 __free_pages(get_a_page(vi, GFP_KERNEL), 0);
1045
1046         free_netdev(vi->dev);
1047 }
1048
1049 static struct virtio_device_id id_table[] = {
1050         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1051         { 0 },
1052 };
1053
1054 static unsigned int features[] = {
1055         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1056         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1057         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
1058         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1059         VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
1060         VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
1061         VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
1062 };
1063
1064 static struct virtio_driver virtio_net_driver = {
1065         .feature_table = features,
1066         .feature_table_size = ARRAY_SIZE(features),
1067         .driver.name =  KBUILD_MODNAME,
1068         .driver.owner = THIS_MODULE,
1069         .id_table =     id_table,
1070         .probe =        virtnet_probe,
1071         .remove =       __devexit_p(virtnet_remove),
1072         .config_changed = virtnet_config_changed,
1073 };
1074
1075 static int __init init(void)
1076 {
1077         return register_virtio_driver(&virtio_net_driver);
1078 }
1079
1080 static void __exit fini(void)
1081 {
1082         unregister_virtio_driver(&virtio_net_driver);
1083 }
1084 module_init(init);
1085 module_exit(fini);
1086
1087 MODULE_DEVICE_TABLE(virtio, id_table);
1088 MODULE_DESCRIPTION("Virtio network driver");
1089 MODULE_LICENSE("GPL");