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 #include <linux/cpu.h>
  30
  31 static int napi_weight = 128;
  32 module_param(napi_weight, int, 0444);
  33
  34 static bool csum = true, gso = true;
  35 module_param(csum, bool, 0444);
  36 module_param(gso, bool, 0444);
  37
  38 /* FIXME: MTU in config. */
  39 #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
  40 #define GOOD_COPY_LEN   128
  41
  42 #define VIRTNET_SEND_COMMAND_SG_MAX    2
  43 #define VIRTNET_DRIVER_VERSION "1.0.0"
  44
  45 struct virtnet_stats {
  46         struct u64_stats_sync tx_syncp;
  47         struct u64_stats_sync rx_syncp;
  48         u64 tx_bytes;
  49         u64 tx_packets;
  50
  51         u64 rx_bytes;
  52         u64 rx_packets;
  53 };
  54
  55 /* Internal representation of a send virtqueue */
  56 struct send_queue {
  57         /* Virtqueue associated with this send _queue */
  58         struct virtqueue *vq;
  59
  60         /* TX: fragments + linear part + virtio header */
  61         struct scatterlist sg[MAX_SKB_FRAGS + 2];
  62
  63         /* Name of the send queue: output.$index */
  64         char name[40];
  65 };
  66
  67 /* Internal representation of a receive virtqueue */
  68 struct receive_queue {
  69         /* Virtqueue associated with this receive_queue */
  70         struct virtqueue *vq;
  71
  72         struct napi_struct napi;
  73
  74         /* Number of input buffers, and max we've ever had. */
  75         unsigned int num, max;
  76
  77         /* Chain pages by the private ptr. */
  78         struct page *pages;
  79
  80         /* RX: fragments + linear part + virtio header */
  81         struct scatterlist sg[MAX_SKB_FRAGS + 2];
  82
  83         /* Name of this receive queue: input.$index */
  84         char name[40];
  85 };
  86
  87 struct virtnet_info {
  88         struct virtio_device *vdev;
  89         struct virtqueue *cvq;
  90         struct net_device *dev;
  91         struct send_queue *sq;
  92         struct receive_queue *rq;
  93         unsigned int status;
  94
  95         /* Max # of queue pairs supported by the device */
  96         u16 max_queue_pairs;
  97
  98         /* # of queue pairs currently used by the driver */
  99         u16 curr_queue_pairs;
 100
 101         /* I like... big packets and I cannot lie! */
 102         bool big_packets;
 103
 104         /* Host will merge rx buffers for big packets (shake it! shake it!) */
 105         bool mergeable_rx_bufs;
 106
 107         /* Has control virtqueue */
 108         bool has_cvq;
 109
 110         /* enable config space updates */
 111         bool config_enable;
 112
 113         /* Active statistics */
 114         struct virtnet_stats __percpu *stats;
 115
 116         /* Work struct for refilling if we run low on memory. */
 117         struct delayed_work refill;
 118
 119         /* Work struct for config space updates */
 120         struct work_struct config_work;
 121
 122         /* Lock for config space updates */
 123         struct mutex config_lock;
 124
 125         /* Does the affinity hint is set for virtqueues? */
 126         bool affinity_hint_set;
 127
 128         /* Per-cpu variable to show the mapping from CPU to virtqueue */
 129         int __percpu *vq_index;
 130
 131         /* CPU hot plug notifier */
 132         struct notifier_block nb;
 133 };
 134
 135 struct skb_vnet_hdr {
 136         union {
 137                 struct virtio_net_hdr hdr;
 138                 struct virtio_net_hdr_mrg_rxbuf mhdr;
 139         };
 140 };
 141
 142 struct padded_vnet_hdr {
 143         struct virtio_net_hdr hdr;
 144         /*
 145          * virtio_net_hdr should be in a separated sg buffer because of a
 146          * QEMU bug, and data sg buffer shares same page with this header sg.
 147          * This padding makes next sg 16 byte aligned after virtio_net_hdr.
 148          */
 149         char padding[6];
 150 };
 151
 152 /* Converting between virtqueue no. and kernel tx/rx queue no.
 153  * 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq
 154  */
 155 static int vq2txq(struct virtqueue *vq)
 156 {
 157         return (vq->index - 1) / 2;
 158 }
 159
 160 static int txq2vq(int txq)
 161 {
 162         return txq * 2 + 1;
 163 }
 164
 165 static int vq2rxq(struct virtqueue *vq)
 166 {
 167         return vq->index / 2;
 168 }
 169
 170 static int rxq2vq(int rxq)
 171 {
 172         return rxq * 2;
 173 }
 174
 175 static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
 176 {
 177         return (struct skb_vnet_hdr *)skb->cb;
 178 }
 179
 180 /*
 181  * private is used to chain pages for big packets, put the whole
 182  * most recent used list in the beginning for reuse
 183  */
 184 static void give_pages(struct receive_queue *rq, struct page *page)
 185 {
 186         struct page *end;
 187
 188         /* Find end of list, sew whole thing into vi->rq.pages. */
 189         for (end = page; end->private; end = (struct page *)end->private);
 190         end->private = (unsigned long)rq->pages;
 191         rq->pages = page;
 192 }
 193
 194 static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
 195 {
 196         struct page *p = rq->pages;
 197
 198         if (p) {
 199                 rq->pages = (struct page *)p->private;
 200                 /* clear private here, it is used to chain pages */
 201                 p->private = 0;
 202         } else
 203                 p = alloc_page(gfp_mask);
 204         return p;
 205 }
 206
 207 static void skb_xmit_done(struct virtqueue *vq)
 208 {
 209         struct virtnet_info *vi = vq->vdev->priv;
 210
 211         /* Suppress further interrupts. */
 212         virtqueue_disable_cb(vq);
 213
 214         /* We were probably waiting for more output buffers. */
 215         netif_wake_subqueue(vi->dev, vq2txq(vq));
 216 }
 217
 218 static void set_skb_frag(struct sk_buff *skb, struct page *page,
 219                          unsigned int offset, unsigned int *len)
 220 {
 221         int size = min((unsigned)PAGE_SIZE - offset, *len);
 222         int i = skb_shinfo(skb)->nr_frags;
 223
 224         __skb_fill_page_desc(skb, i, page, offset, size);
 225
 226         skb->data_len += size;
 227         skb->len += size;
 228         skb->truesize += PAGE_SIZE;
 229         skb_shinfo(skb)->nr_frags++;
 230         skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
 231         *len -= size;
 232 }
 233
 234 /* Called from bottom half context */
 235 static struct sk_buff *page_to_skb(struct receive_queue *rq,
 236                                    struct page *page, unsigned int len)
 237 {
 238         struct virtnet_info *vi = rq->vq->vdev->priv;
 239         struct sk_buff *skb;
 240         struct skb_vnet_hdr *hdr;
 241         unsigned int copy, hdr_len, offset;
 242         char *p;
 243
 244         p = page_address(page);
 245
 246         /* copy small packet so we can reuse these pages for small data */
 247         skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
 248         if (unlikely(!skb))
 249                 return NULL;
 250
 251         hdr = skb_vnet_hdr(skb);
 252
 253         if (vi->mergeable_rx_bufs) {
 254                 hdr_len = sizeof hdr->mhdr;
 255                 offset = hdr_len;
 256         } else {
 257                 hdr_len = sizeof hdr->hdr;
 258                 offset = sizeof(struct padded_vnet_hdr);
 259         }
 260
 261         memcpy(hdr, p, hdr_len);
 262
 263         len -= hdr_len;
 264         p += offset;
 265
 266         copy = len;
 267         if (copy > skb_tailroom(skb))
 268                 copy = skb_tailroom(skb);
 269         memcpy(skb_put(skb, copy), p, copy);
 270
 271         len -= copy;
 272         offset += copy;
 273
 274         /*
 275          * Verify that we can indeed put this data into a skb.
 276          * This is here to handle cases when the device erroneously
 277          * tries to receive more than is possible. This is usually
 278          * the case of a broken device.
 279          */
 280         if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
 281                 net_dbg_ratelimited("%s: too much data\n", skb->dev->name);
 282                 dev_kfree_skb(skb);
 283                 return NULL;
 284         }
 285
 286         while (len) {
 287                 set_skb_frag(skb, page, offset, &len);
 288                 page = (struct page *)page->private;
 289                 offset = 0;
 290         }
 291
 292         if (page)
 293                 give_pages(rq, page);
 294
 295         return skb;
 296 }
 297
 298 static int receive_mergeable(struct receive_queue *rq, struct sk_buff *skb)
 299 {
 300         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 301         struct page *page;
 302         int num_buf, i, len;
 303
 304         num_buf = hdr->mhdr.num_buffers;
 305         while (--num_buf) {
 306                 i = skb_shinfo(skb)->nr_frags;
 307                 if (i >= MAX_SKB_FRAGS) {
 308                         pr_debug("%s: packet too long\n", skb->dev->name);
 309                         skb->dev->stats.rx_length_errors++;
 310                         return -EINVAL;
 311                 }
 312                 page = virtqueue_get_buf(rq->vq, &len);
 313                 if (!page) {
 314                         pr_debug("%s: rx error: %d buffers missing\n",
 315                                  skb->dev->name, hdr->mhdr.num_buffers);
 316                         skb->dev->stats.rx_length_errors++;
 317                         return -EINVAL;
 318                 }
 319
 320                 if (len > PAGE_SIZE)
 321                         len = PAGE_SIZE;
 322
 323                 set_skb_frag(skb, page, 0, &len);
 324
 325                 --rq->num;
 326         }
 327         return 0;
 328 }
 329
 330 static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
 331 {
 332         struct virtnet_info *vi = rq->vq->vdev->priv;
 333         struct net_device *dev = vi->dev;
 334         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
 335         struct sk_buff *skb;
 336         struct page *page;
 337         struct skb_vnet_hdr *hdr;
 338
 339         if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
 340                 pr_debug("%s: short packet %i\n", dev->name, len);
 341                 dev->stats.rx_length_errors++;
 342                 if (vi->mergeable_rx_bufs || vi->big_packets)
 343                         give_pages(rq, buf);
 344                 else
 345                         dev_kfree_skb(buf);
 346                 return;
 347         }
 348
 349         if (!vi->mergeable_rx_bufs && !vi->big_packets) {
 350                 skb = buf;
 351                 len -= sizeof(struct virtio_net_hdr);
 352                 skb_trim(skb, len);
 353         } else {
 354                 page = buf;
 355                 skb = page_to_skb(rq, page, len);
 356                 if (unlikely(!skb)) {
 357                         dev->stats.rx_dropped++;
 358                         give_pages(rq, page);
 359                         return;
 360                 }
 361                 if (vi->mergeable_rx_bufs)
 362                         if (receive_mergeable(rq, skb)) {
 363                                 dev_kfree_skb(skb);
 364                                 return;
 365                         }
 366         }
 367
 368         hdr = skb_vnet_hdr(skb);
 369
 370         u64_stats_update_begin(&stats->rx_syncp);
 371         stats->rx_bytes += skb->len;
 372         stats->rx_packets++;
 373         u64_stats_update_end(&stats->rx_syncp);
 374
 375         if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 376                 pr_debug("Needs csum!\n");
 377                 if (!skb_partial_csum_set(skb,
 378                                           hdr->hdr.csum_start,
 379                                           hdr->hdr.csum_offset))
 380                         goto frame_err;
 381         } else if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID) {
 382                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 383         }
 384
 385         skb->protocol = eth_type_trans(skb, dev);
 386         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
 387                  ntohs(skb->protocol), skb->len, skb->pkt_type);
 388
 389         if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 390                 pr_debug("GSO!\n");
 391                 switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 392                 case VIRTIO_NET_HDR_GSO_TCPV4:
 393                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 394                         break;
 395                 case VIRTIO_NET_HDR_GSO_UDP:
 396                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 397                         break;
 398                 case VIRTIO_NET_HDR_GSO_TCPV6:
 399                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 400                         break;
 401                 default:
 402                         net_warn_ratelimited("%s: bad gso type %u.\n",
 403                                              dev->name, hdr->hdr.gso_type);
 404                         goto frame_err;
 405                 }
 406
 407                 if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 408                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 409
 410                 skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
 411                 if (skb_shinfo(skb)->gso_size == 0) {
 412                         net_warn_ratelimited("%s: zero gso size.\n", dev->name);
 413                         goto frame_err;
 414                 }
 415
 416                 /* Header must be checked, and gso_segs computed. */
 417                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 418                 skb_shinfo(skb)->gso_segs = 0;
 419         }
 420
 421         netif_receive_skb(skb);
 422         return;
 423
 424 frame_err:
 425         dev->stats.rx_frame_errors++;
 426         dev_kfree_skb(skb);
 427 }
 428
 429 static int add_recvbuf_small(struct receive_queue *rq, gfp_t gfp)
 430 {
 431         struct virtnet_info *vi = rq->vq->vdev->priv;
 432         struct sk_buff *skb;
 433         struct skb_vnet_hdr *hdr;
 434         int err;
 435
 436         skb = __netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN, gfp);
 437         if (unlikely(!skb))
 438                 return -ENOMEM;
 439
 440         skb_put(skb, MAX_PACKET_LEN);
 441
 442         hdr = skb_vnet_hdr(skb);
 443         sg_set_buf(rq->sg, &hdr->hdr, sizeof hdr->hdr);
 444
 445         skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
 446
 447         err = virtqueue_add_buf(rq->vq, rq->sg, 0, 2, skb, gfp);
 448         if (err < 0)
 449                 dev_kfree_skb(skb);
 450
 451         return err;
 452 }
 453
 454 static int add_recvbuf_big(struct receive_queue *rq, gfp_t gfp)
 455 {
 456         struct page *first, *list = NULL;
 457         char *p;
 458         int i, err, offset;
 459
 460         /* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */
 461         for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
 462                 first = get_a_page(rq, gfp);
 463                 if (!first) {
 464                         if (list)
 465                                 give_pages(rq, list);
 466                         return -ENOMEM;
 467                 }
 468                 sg_set_buf(&rq->sg[i], page_address(first), PAGE_SIZE);
 469
 470                 /* chain new page in list head to match sg */
 471                 first->private = (unsigned long)list;
 472                 list = first;
 473         }
 474
 475         first = get_a_page(rq, gfp);
 476         if (!first) {
 477                 give_pages(rq, list);
 478                 return -ENOMEM;
 479         }
 480         p = page_address(first);
 481
 482         /* rq->sg[0], rq->sg[1] share the same page */
 483         /* a separated rq->sg[0] for virtio_net_hdr only due to QEMU bug */
 484         sg_set_buf(&rq->sg[0], p, sizeof(struct virtio_net_hdr));
 485
 486         /* rq->sg[1] for data packet, from offset */
 487         offset = sizeof(struct padded_vnet_hdr);
 488         sg_set_buf(&rq->sg[1], p + offset, PAGE_SIZE - offset);
 489
 490         /* chain first in list head */
 491         first->private = (unsigned long)list;
 492         err = virtqueue_add_buf(rq->vq, rq->sg, 0, MAX_SKB_FRAGS + 2,
 493                                 first, gfp);
 494         if (err < 0)
 495                 give_pages(rq, first);
 496
 497         return err;
 498 }
 499
 500 static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
 501 {
 502         struct page *page;
 503         int err;
 504
 505         page = get_a_page(rq, gfp);
 506         if (!page)
 507                 return -ENOMEM;
 508
 509         sg_init_one(rq->sg, page_address(page), PAGE_SIZE);
 510
 511         err = virtqueue_add_buf(rq->vq, rq->sg, 0, 1, page, gfp);
 512         if (err < 0)
 513                 give_pages(rq, page);
 514
 515         return err;
 516 }
 517
 518 /*
 519  * Returns false if we couldn't fill entirely (OOM).
 520  *
 521  * Normally run in the receive path, but can also be run from ndo_open
 522  * before we're receiving packets, or from refill_work which is
 523  * careful to disable receiving (using napi_disable).
 524  */
 525 static bool try_fill_recv(struct receive_queue *rq, gfp_t gfp)
 526 {
 527         struct virtnet_info *vi = rq->vq->vdev->priv;
 528         int err;
 529         bool oom;
 530
 531         do {
 532                 if (vi->mergeable_rx_bufs)
 533                         err = add_recvbuf_mergeable(rq, gfp);
 534                 else if (vi->big_packets)
 535                         err = add_recvbuf_big(rq, gfp);
 536                 else
 537                         err = add_recvbuf_small(rq, gfp);
 538
 539                 oom = err == -ENOMEM;
 540                 if (err)
 541                         break;
 542                 ++rq->num;
 543         } while (rq->vq->num_free);
 544         if (unlikely(rq->num > rq->max))
 545                 rq->max = rq->num;
 546         virtqueue_kick(rq->vq);
 547         return !oom;
 548 }
 549
 550 static void skb_recv_done(struct virtqueue *rvq)
 551 {
 552         struct virtnet_info *vi = rvq->vdev->priv;
 553         struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
 554
 555         /* Schedule NAPI, Suppress further interrupts if successful. */
 556         if (napi_schedule_prep(&rq->napi)) {
 557                 virtqueue_disable_cb(rvq);
 558                 __napi_schedule(&rq->napi);
 559         }
 560 }
 561
 562 static void virtnet_napi_enable(struct receive_queue *rq)
 563 {
 564         napi_enable(&rq->napi);
 565
 566         /* If all buffers were filled by other side before we napi_enabled, we
 567          * won't get another interrupt, so process any outstanding packets
 568          * now.  virtnet_poll wants re-enable the queue, so we disable here.
 569          * We synchronize against interrupts via NAPI_STATE_SCHED */
 570         if (napi_schedule_prep(&rq->napi)) {
 571                 virtqueue_disable_cb(rq->vq);
 572                 local_bh_disable();
 573                 __napi_schedule(&rq->napi);
 574                 local_bh_enable();
 575         }
 576 }
 577
 578 static void refill_work(struct work_struct *work)
 579 {
 580         struct virtnet_info *vi =
 581                 container_of(work, struct virtnet_info, refill.work);
 582         bool still_empty;
 583         int i;
 584
 585         for (i = 0; i < vi->max_queue_pairs; i++) {
 586                 struct receive_queue *rq = &vi->rq[i];
 587
 588                 napi_disable(&rq->napi);
 589                 still_empty = !try_fill_recv(rq, GFP_KERNEL);
 590                 virtnet_napi_enable(rq);
 591
 592                 /* In theory, this can happen: if we don't get any buffers in
 593                  * we will *never* try to fill again.
 594                  */
 595                 if (still_empty)
 596                         schedule_delayed_work(&vi->refill, HZ/2);
 597         }
 598 }
 599
 600 static int virtnet_poll(struct napi_struct *napi, int budget)
 601 {
 602         struct receive_queue *rq =
 603                 container_of(napi, struct receive_queue, napi);
 604         struct virtnet_info *vi = rq->vq->vdev->priv;
 605         void *buf;
 606         unsigned int len, received = 0;
 607
 608 again:
 609         while (received < budget &&
 610                (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
 611                 receive_buf(rq, buf, len);
 612                 --rq->num;
 613                 received++;
 614         }
 615
 616         if (rq->num < rq->max / 2) {
 617                 if (!try_fill_recv(rq, GFP_ATOMIC))
 618                         schedule_delayed_work(&vi->refill, 0);
 619         }
 620
 621         /* Out of packets? */
 622         if (received < budget) {
 623                 napi_complete(napi);
 624                 if (unlikely(!virtqueue_enable_cb(rq->vq)) &&
 625                     napi_schedule_prep(napi)) {
 626                         virtqueue_disable_cb(rq->vq);
 627                         __napi_schedule(napi);
 628                         goto again;
 629                 }
 630         }
 631
 632         return received;
 633 }
 634
 635 static int virtnet_open(struct net_device *dev)
 636 {
 637         struct virtnet_info *vi = netdev_priv(dev);
 638         int i;
 639
 640         for (i = 0; i < vi->max_queue_pairs; i++) {
 641                 /* Make sure we have some buffers: if oom use wq. */
 642                 if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
 643                         schedule_delayed_work(&vi->refill, 0);
 644                 virtnet_napi_enable(&vi->rq[i]);
 645         }
 646
 647         return 0;
 648 }
 649
 650 static void free_old_xmit_skbs(struct send_queue *sq)
 651 {
 652         struct sk_buff *skb;
 653         unsigned int len;
 654         struct virtnet_info *vi = sq->vq->vdev->priv;
 655         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
 656
 657         while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {
 658                 pr_debug("Sent skb %p\n", skb);
 659
 660                 u64_stats_update_begin(&stats->tx_syncp);
 661                 stats->tx_bytes += skb->len;
 662                 stats->tx_packets++;
 663                 u64_stats_update_end(&stats->tx_syncp);
 664
 665                 dev_kfree_skb_any(skb);
 666         }
 667 }
 668
 669 static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
 670 {
 671         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 672         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 673         struct virtnet_info *vi = sq->vq->vdev->priv;
 674         unsigned num_sg;
 675
 676         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
 677
 678         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 679                 hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 680                 hdr->hdr.csum_start = skb_checksum_start_offset(skb);
 681                 hdr->hdr.csum_offset = skb->csum_offset;
 682         } else {
 683                 hdr->hdr.flags = 0;
 684                 hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
 685         }
 686
 687         if (skb_is_gso(skb)) {
 688                 hdr->hdr.hdr_len = skb_headlen(skb);
 689                 hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
 690                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 691                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 692                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 693                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 694                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 695                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 696                 else
 697                         BUG();
 698                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
 699                         hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 700         } else {
 701                 hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 702                 hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
 703         }
 704
 705         hdr->mhdr.num_buffers = 0;
 706
 707         /* Encode metadata header at front. */
 708         if (vi->mergeable_rx_bufs)
 709                 sg_set_buf(sq->sg, &hdr->mhdr, sizeof hdr->mhdr);
 710         else
 711                 sg_set_buf(sq->sg, &hdr->hdr, sizeof hdr->hdr);
 712
 713         num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
 714         return virtqueue_add_buf(sq->vq, sq->sg, num_sg,
 715                                  0, skb, GFP_ATOMIC);
 716 }
 717
 718 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 719 {
 720         struct virtnet_info *vi = netdev_priv(dev);
 721         int qnum = skb_get_queue_mapping(skb);
 722         struct send_queue *sq = &vi->sq[qnum];
 723         int err;
 724
 725         /* Free up any pending old buffers before queueing new ones. */
 726         free_old_xmit_skbs(sq);
 727
 728         /* Try to transmit */
 729         err = xmit_skb(sq, skb);
 730
 731         /* This should not happen! */
 732         if (unlikely(err)) {
 733                 dev->stats.tx_fifo_errors++;
 734                 if (net_ratelimit())
 735                         dev_warn(&dev->dev,
 736                                  "Unexpected TXQ (%d) queue failure: %d\n", qnum, err);
 737                 dev->stats.tx_dropped++;
 738                 kfree_skb(skb);
 739                 return NETDEV_TX_OK;
 740         }
 741         virtqueue_kick(sq->vq);
 742
 743         /* Don't wait up for transmitted skbs to be freed. */
 744         skb_orphan(skb);
 745         nf_reset(skb);
 746
 747         /* Apparently nice girls don't return TX_BUSY; stop the queue
 748          * before it gets out of hand.  Naturally, this wastes entries. */
 749         if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
 750                 netif_stop_subqueue(dev, qnum);
 751                 if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
 752                         /* More just got used, free them then recheck. */
 753                         free_old_xmit_skbs(sq);
 754                         if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
 755                                 netif_start_subqueue(dev, qnum);
 756                                 virtqueue_disable_cb(sq->vq);
 757                         }
 758                 }
 759         }
 760
 761         return NETDEV_TX_OK;
 762 }
 763
 764 /*
 765  * Send command via the control virtqueue and check status.  Commands
 766  * supported by the hypervisor, as indicated by feature bits, should
 767  * never fail unless improperly formated.
 768  */
 769 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
 770                                  struct scatterlist *data, int out, int in)
 771 {
 772         struct scatterlist *s, sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
 773         struct virtio_net_ctrl_hdr ctrl;
 774         virtio_net_ctrl_ack status = ~0;
 775         unsigned int tmp;
 776         int i;
 777
 778         /* Caller should know better */
 779         BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ||
 780                 (out + in > VIRTNET_SEND_COMMAND_SG_MAX));
 781
 782         out++; /* Add header */
 783         in++; /* Add return status */
 784
 785         ctrl.class = class;
 786         ctrl.cmd = cmd;
 787
 788         sg_init_table(sg, out + in);
 789
 790         sg_set_buf(&sg[0], &ctrl, sizeof(ctrl));
 791         for_each_sg(data, s, out + in - 2, i)
 792                 sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
 793         sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
 794
 795         BUG_ON(virtqueue_add_buf(vi->cvq, sg, out, in, vi, GFP_ATOMIC) < 0);
 796
 797         virtqueue_kick(vi->cvq);
 798
 799         /* Spin for a response, the kick causes an ioport write, trapping
 800          * into the hypervisor, so the request should be handled immediately.
 801          */
 802         while (!virtqueue_get_buf(vi->cvq, &tmp))
 803                 cpu_relax();
 804
 805         return status == VIRTIO_NET_OK;
 806 }
 807
 808 static int virtnet_set_mac_address(struct net_device *dev, void *p)
 809 {
 810         struct virtnet_info *vi = netdev_priv(dev);
 811         struct virtio_device *vdev = vi->vdev;
 812         int ret;
 813         struct sockaddr *addr = p;
 814         struct scatterlist sg;
 815
 816         ret = eth_prepare_mac_addr_change(dev, p);
 817         if (ret)
 818                 return ret;
 819
 820         if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
 821                 sg_init_one(&sg, addr->sa_data, dev->addr_len);
 822                 if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
 823                                           VIRTIO_NET_CTRL_MAC_ADDR_SET,
 824                                           &sg, 1, 0)) {
 825                         dev_warn(&vdev->dev,
 826                                  "Failed to set mac address by vq command.\n");
 827                         return -EINVAL;
 828                 }
 829         } else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
 830                 vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
 831                                   addr->sa_data, dev->addr_len);
 832         }
 833
 834         eth_commit_mac_addr_change(dev, p);
 835
 836         return 0;
 837 }
 838
 839 static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
 840                                                struct rtnl_link_stats64 *tot)
 841 {
 842         struct virtnet_info *vi = netdev_priv(dev);
 843         int cpu;
 844         unsigned int start;
 845
 846         for_each_possible_cpu(cpu) {
 847                 struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
 848                 u64 tpackets, tbytes, rpackets, rbytes;
 849
 850                 do {
 851                         start = u64_stats_fetch_begin_bh(&stats->tx_syncp);
 852                         tpackets = stats->tx_packets;
 853                         tbytes   = stats->tx_bytes;
 854                 } while (u64_stats_fetch_retry_bh(&stats->tx_syncp, start));
 855
 856                 do {
 857                         start = u64_stats_fetch_begin_bh(&stats->rx_syncp);
 858                         rpackets = stats->rx_packets;
 859                         rbytes   = stats->rx_bytes;
 860                 } while (u64_stats_fetch_retry_bh(&stats->rx_syncp, start));
 861
 862                 tot->rx_packets += rpackets;
 863                 tot->tx_packets += tpackets;
 864                 tot->rx_bytes   += rbytes;
 865                 tot->tx_bytes   += tbytes;
 866         }
 867
 868         tot->tx_dropped = dev->stats.tx_dropped;
 869         tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
 870         tot->rx_dropped = dev->stats.rx_dropped;
 871         tot->rx_length_errors = dev->stats.rx_length_errors;
 872         tot->rx_frame_errors = dev->stats.rx_frame_errors;
 873
 874         return tot;
 875 }
 876
 877 #ifdef CONFIG_NET_POLL_CONTROLLER
 878 static void virtnet_netpoll(struct net_device *dev)
 879 {
 880         struct virtnet_info *vi = netdev_priv(dev);
 881         int i;
 882
 883         for (i = 0; i < vi->curr_queue_pairs; i++)
 884                 napi_schedule(&vi->rq[i].napi);
 885 }
 886 #endif
 887
 888 static void virtnet_ack_link_announce(struct virtnet_info *vi)
 889 {
 890         rtnl_lock();
 891         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
 892                                   VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL,
 893                                   0, 0))
 894                 dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
 895         rtnl_unlock();
 896 }
 897
 898 static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
 899 {
 900         struct scatterlist sg;
 901         struct virtio_net_ctrl_mq s;
 902         struct net_device *dev = vi->dev;
 903
 904         if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
 905                 return 0;
 906
 907         s.virtqueue_pairs = queue_pairs;
 908         sg_init_one(&sg, &s, sizeof(s));
 909
 910         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
 911                                   VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg, 1, 0)){
 912                 dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
 913                          queue_pairs);
 914                 return -EINVAL;
 915         } else
 916                 vi->curr_queue_pairs = queue_pairs;
 917
 918         return 0;
 919 }
 920
 921 static int virtnet_close(struct net_device *dev)
 922 {
 923         struct virtnet_info *vi = netdev_priv(dev);
 924         int i;
 925
 926         /* Make sure refill_work doesn't re-enable napi! */
 927         cancel_delayed_work_sync(&vi->refill);
 928
 929         for (i = 0; i < vi->max_queue_pairs; i++)
 930                 napi_disable(&vi->rq[i].napi);
 931
 932         return 0;
 933 }
 934
 935 static void virtnet_set_rx_mode(struct net_device *dev)
 936 {
 937         struct virtnet_info *vi = netdev_priv(dev);
 938         struct scatterlist sg[2];
 939         u8 promisc, allmulti;
 940         struct virtio_net_ctrl_mac *mac_data;
 941         struct netdev_hw_addr *ha;
 942         int uc_count;
 943         int mc_count;
 944         void *buf;
 945         int i;
 946
 947         /* We can't dynamicaly set ndo_set_rx_mode, so return gracefully */
 948         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
 949                 return;
 950
 951         promisc = ((dev->flags & IFF_PROMISC) != 0);
 952         allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
 953
 954         sg_init_one(sg, &promisc, sizeof(promisc));
 955
 956         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 957                                   VIRTIO_NET_CTRL_RX_PROMISC,
 958                                   sg, 1, 0))
 959                 dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
 960                          promisc ? "en" : "dis");
 961
 962         sg_init_one(sg, &allmulti, sizeof(allmulti));
 963
 964         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 965                                   VIRTIO_NET_CTRL_RX_ALLMULTI,
 966                                   sg, 1, 0))
 967                 dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
 968                          allmulti ? "en" : "dis");
 969
 970         uc_count = netdev_uc_count(dev);
 971         mc_count = netdev_mc_count(dev);
 972         /* MAC filter - use one buffer for both lists */
 973         buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
 974                       (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
 975         mac_data = buf;
 976         if (!buf)
 977                 return;
 978
 979         sg_init_table(sg, 2);
 980
 981         /* Store the unicast list and count in the front of the buffer */
 982         mac_data->entries = uc_count;
 983         i = 0;
 984         netdev_for_each_uc_addr(ha, dev)
 985                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 986
 987         sg_set_buf(&sg[0], mac_data,
 988                    sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
 989
 990         /* multicast list and count fill the end */
 991         mac_data = (void *)&mac_data->macs[uc_count][0];
 992
 993         mac_data->entries = mc_count;
 994         i = 0;
 995         netdev_for_each_mc_addr(ha, dev)
 996                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 997
 998         sg_set_buf(&sg[1], mac_data,
 999                    sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
1000
1001         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1002                                   VIRTIO_NET_CTRL_MAC_TABLE_SET,
1003                                   sg, 2, 0))
1004                 dev_warn(&dev->dev, "Failed to set MAC fitler table.\n");
1005
1006         kfree(buf);
1007 }
1008
1009 static int virtnet_vlan_rx_add_vid(struct net_device *dev,
1010                                    __be16 proto, u16 vid)
1011 {
1012         struct virtnet_info *vi = netdev_priv(dev);
1013         struct scatterlist sg;
1014
1015         sg_init_one(&sg, &vid, sizeof(vid));
1016
1017         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1018                                   VIRTIO_NET_CTRL_VLAN_ADD, &sg, 1, 0))
1019                 dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
1020         return 0;
1021 }
1022
1023 static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
1024                                     __be16 proto, u16 vid)
1025 {
1026         struct virtnet_info *vi = netdev_priv(dev);
1027         struct scatterlist sg;
1028
1029         sg_init_one(&sg, &vid, sizeof(vid));
1030
1031         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1032                                   VIRTIO_NET_CTRL_VLAN_DEL, &sg, 1, 0))
1033                 dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
1034         return 0;
1035 }
1036
1037 static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
1038 {
1039         int i;
1040         int cpu;
1041
1042         if (vi->affinity_hint_set) {
1043                 for (i = 0; i < vi->max_queue_pairs; i++) {
1044                         virtqueue_set_affinity(vi->rq[i].vq, -1);
1045                         virtqueue_set_affinity(vi->sq[i].vq, -1);
1046                 }
1047
1048                 vi->affinity_hint_set = false;
1049         }
1050
1051         i = 0;
1052         for_each_online_cpu(cpu) {
1053                 if (cpu == hcpu) {
1054                         *per_cpu_ptr(vi->vq_index, cpu) = -1;
1055                 } else {
1056                         *per_cpu_ptr(vi->vq_index, cpu) =
1057                                 ++i % vi->curr_queue_pairs;
1058                 }
1059         }
1060 }
1061
1062 static void virtnet_set_affinity(struct virtnet_info *vi)
1063 {
1064         int i;
1065         int cpu;
1066
1067         /* In multiqueue mode, when the number of cpu is equal to the number of
1068          * queue pairs, we let the queue pairs to be private to one cpu by
1069          * setting the affinity hint to eliminate the contention.
1070          */
1071         if (vi->curr_queue_pairs == 1 ||
1072             vi->max_queue_pairs != num_online_cpus()) {
1073                 virtnet_clean_affinity(vi, -1);
1074                 return;
1075         }
1076
1077         i = 0;
1078         for_each_online_cpu(cpu) {
1079                 virtqueue_set_affinity(vi->rq[i].vq, cpu);
1080                 virtqueue_set_affinity(vi->sq[i].vq, cpu);
1081                 *per_cpu_ptr(vi->vq_index, cpu) = i;
1082                 i++;
1083         }
1084
1085         vi->affinity_hint_set = true;
1086 }
1087
1088 static int virtnet_cpu_callback(struct notifier_block *nfb,
1089                                 unsigned long action, void *hcpu)
1090 {
1091         struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
1092
1093         switch(action & ~CPU_TASKS_FROZEN) {
1094         case CPU_ONLINE:
1095         case CPU_DOWN_FAILED:
1096         case CPU_DEAD:
1097                 virtnet_set_affinity(vi);
1098                 break;
1099         case CPU_DOWN_PREPARE:
1100                 virtnet_clean_affinity(vi, (long)hcpu);
1101                 break;
1102         default:
1103                 break;
1104         }
1105         return NOTIFY_OK;
1106 }
1107
1108 static void virtnet_get_ringparam(struct net_device *dev,
1109                                 struct ethtool_ringparam *ring)
1110 {
1111         struct virtnet_info *vi = netdev_priv(dev);
1112
1113         ring->rx_max_pending = virtqueue_get_vring_size(vi->rq[0].vq);
1114         ring->tx_max_pending = virtqueue_get_vring_size(vi->sq[0].vq);
1115         ring->rx_pending = ring->rx_max_pending;
1116         ring->tx_pending = ring->tx_max_pending;
1117 }
1118
1119
1120 static void virtnet_get_drvinfo(struct net_device *dev,
1121                                 struct ethtool_drvinfo *info)
1122 {
1123         struct virtnet_info *vi = netdev_priv(dev);
1124         struct virtio_device *vdev = vi->vdev;
1125
1126         strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
1127         strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
1128         strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
1129
1130 }
1131
1132 /* TODO: Eliminate OOO packets during switching */
1133 static int virtnet_set_channels(struct net_device *dev,
1134                                 struct ethtool_channels *channels)
1135 {
1136         struct virtnet_info *vi = netdev_priv(dev);
1137         u16 queue_pairs = channels->combined_count;
1138         int err;
1139
1140         /* We don't support separate rx/tx channels.
1141          * We don't allow setting 'other' channels.
1142          */
1143         if (channels->rx_count || channels->tx_count || channels->other_count)
1144                 return -EINVAL;
1145
1146         if (queue_pairs > vi->max_queue_pairs)
1147                 return -EINVAL;
1148
1149         get_online_cpus();
1150         err = virtnet_set_queues(vi, queue_pairs);
1151         if (!err) {
1152                 netif_set_real_num_tx_queues(dev, queue_pairs);
1153                 netif_set_real_num_rx_queues(dev, queue_pairs);
1154
1155                 virtnet_set_affinity(vi);
1156         }
1157         put_online_cpus();
1158
1159         return err;
1160 }
1161
1162 static void virtnet_get_channels(struct net_device *dev,
1163                                  struct ethtool_channels *channels)
1164 {
1165         struct virtnet_info *vi = netdev_priv(dev);
1166
1167         channels->combined_count = vi->curr_queue_pairs;
1168         channels->max_combined = vi->max_queue_pairs;
1169         channels->max_other = 0;
1170         channels->rx_count = 0;
1171         channels->tx_count = 0;
1172         channels->other_count = 0;
1173 }
1174
1175 static const struct ethtool_ops virtnet_ethtool_ops = {
1176         .get_drvinfo = virtnet_get_drvinfo,
1177         .get_link = ethtool_op_get_link,
1178         .get_ringparam = virtnet_get_ringparam,
1179         .set_channels = virtnet_set_channels,
1180         .get_channels = virtnet_get_channels,
1181 };
1182
1183 #define MIN_MTU 68
1184 #define MAX_MTU 65535
1185
1186 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
1187 {
1188         if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
1189                 return -EINVAL;
1190         dev->mtu = new_mtu;
1191         return 0;
1192 }
1193
1194 /* To avoid contending a lock hold by a vcpu who would exit to host, select the
1195  * txq based on the processor id.
1196  */
1197 static u16 virtnet_select_queue(struct net_device *dev, struct sk_buff *skb)
1198 {
1199         int txq;
1200         struct virtnet_info *vi = netdev_priv(dev);
1201
1202         if (skb_rx_queue_recorded(skb)) {
1203                 txq = skb_get_rx_queue(skb);
1204         } else {
1205                 txq = *__this_cpu_ptr(vi->vq_index);
1206                 if (txq == -1)
1207                         txq = 0;
1208         }
1209
1210         while (unlikely(txq >= dev->real_num_tx_queues))
1211                 txq -= dev->real_num_tx_queues;
1212
1213         return txq;
1214 }
1215
1216 static const struct net_device_ops virtnet_netdev = {
1217         .ndo_open            = virtnet_open,
1218         .ndo_stop            = virtnet_close,
1219         .ndo_start_xmit      = start_xmit,
1220         .ndo_validate_addr   = eth_validate_addr,
1221         .ndo_set_mac_address = virtnet_set_mac_address,
1222         .ndo_set_rx_mode     = virtnet_set_rx_mode,
1223         .ndo_change_mtu      = virtnet_change_mtu,
1224         .ndo_get_stats64     = virtnet_stats,
1225         .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
1226         .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
1227         .ndo_select_queue     = virtnet_select_queue,
1228 #ifdef CONFIG_NET_POLL_CONTROLLER
1229         .ndo_poll_controller = virtnet_netpoll,
1230 #endif
1231 };
1232
1233 static void virtnet_config_changed_work(struct work_struct *work)
1234 {
1235         struct virtnet_info *vi =
1236                 container_of(work, struct virtnet_info, config_work);
1237         u16 v;
1238
1239         mutex_lock(&vi->config_lock);
1240         if (!vi->config_enable)
1241                 goto done;
1242
1243         if (virtio_config_val(vi->vdev, VIRTIO_NET_F_STATUS,
1244                               offsetof(struct virtio_net_config, status),
1245                               &v) < 0)
1246                 goto done;
1247
1248         if (v & VIRTIO_NET_S_ANNOUNCE) {
1249                 netdev_notify_peers(vi->dev);
1250                 virtnet_ack_link_announce(vi);
1251         }
1252
1253         /* Ignore unknown (future) status bits */
1254         v &= VIRTIO_NET_S_LINK_UP;
1255
1256         if (vi->status == v)
1257                 goto done;
1258
1259         vi->status = v;
1260
1261         if (vi->status & VIRTIO_NET_S_LINK_UP) {
1262                 netif_carrier_on(vi->dev);
1263                 netif_tx_wake_all_queues(vi->dev);
1264         } else {
1265                 netif_carrier_off(vi->dev);
1266                 netif_tx_stop_all_queues(vi->dev);
1267         }
1268 done:
1269         mutex_unlock(&vi->config_lock);
1270 }
1271
1272 static void virtnet_config_changed(struct virtio_device *vdev)
1273 {
1274         struct virtnet_info *vi = vdev->priv;
1275
1276         schedule_work(&vi->config_work);
1277 }
1278
1279 static void virtnet_free_queues(struct virtnet_info *vi)
1280 {
1281         kfree(vi->rq);
1282         kfree(vi->sq);
1283 }
1284
1285 static void free_receive_bufs(struct virtnet_info *vi)
1286 {
1287         int i;
1288
1289         for (i = 0; i < vi->max_queue_pairs; i++) {
1290                 while (vi->rq[i].pages)
1291                         __free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
1292         }
1293 }
1294
1295 static void free_unused_bufs(struct virtnet_info *vi)
1296 {
1297         void *buf;
1298         int i;
1299
1300         for (i = 0; i < vi->max_queue_pairs; i++) {
1301                 struct virtqueue *vq = vi->sq[i].vq;
1302                 while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
1303                         dev_kfree_skb(buf);
1304         }
1305
1306         for (i = 0; i < vi->max_queue_pairs; i++) {
1307                 struct virtqueue *vq = vi->rq[i].vq;
1308
1309                 while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
1310                         if (vi->mergeable_rx_bufs || vi->big_packets)
1311                                 give_pages(&vi->rq[i], buf);
1312                         else
1313                                 dev_kfree_skb(buf);
1314                         --vi->rq[i].num;
1315                 }
1316                 BUG_ON(vi->rq[i].num != 0);
1317         }
1318 }
1319
1320 static void virtnet_del_vqs(struct virtnet_info *vi)
1321 {
1322         struct virtio_device *vdev = vi->vdev;
1323
1324         virtnet_clean_affinity(vi, -1);
1325
1326         vdev->config->del_vqs(vdev);
1327
1328         virtnet_free_queues(vi);
1329 }
1330
1331 static int virtnet_find_vqs(struct virtnet_info *vi)
1332 {
1333         vq_callback_t **callbacks;
1334         struct virtqueue **vqs;
1335         int ret = -ENOMEM;
1336         int i, total_vqs;
1337         const char **names;
1338
1339         /* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
1340          * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
1341          * possible control vq.
1342          */
1343         total_vqs = vi->max_queue_pairs * 2 +
1344                     virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
1345
1346         /* Allocate space for find_vqs parameters */
1347         vqs = kzalloc(total_vqs * sizeof(*vqs), GFP_KERNEL);
1348         if (!vqs)
1349                 goto err_vq;
1350         callbacks = kmalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL);
1351         if (!callbacks)
1352                 goto err_callback;
1353         names = kmalloc(total_vqs * sizeof(*names), GFP_KERNEL);
1354         if (!names)
1355                 goto err_names;
1356
1357         /* Parameters for control virtqueue, if any */
1358         if (vi->has_cvq) {
1359                 callbacks[total_vqs - 1] = NULL;
1360                 names[total_vqs - 1] = "control";
1361         }
1362
1363         /* Allocate/initialize parameters for send/receive virtqueues */
1364         for (i = 0; i < vi->max_queue_pairs; i++) {
1365                 callbacks[rxq2vq(i)] = skb_recv_done;
1366                 callbacks[txq2vq(i)] = skb_xmit_done;
1367                 sprintf(vi->rq[i].name, "input.%d", i);
1368                 sprintf(vi->sq[i].name, "output.%d", i);
1369                 names[rxq2vq(i)] = vi->rq[i].name;
1370                 names[txq2vq(i)] = vi->sq[i].name;
1371         }
1372
1373         ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
1374                                          names);
1375         if (ret)
1376                 goto err_find;
1377
1378         if (vi->has_cvq) {
1379                 vi->cvq = vqs[total_vqs - 1];
1380                 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1381                         vi->dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
1382         }
1383
1384         for (i = 0; i < vi->max_queue_pairs; i++) {
1385                 vi->rq[i].vq = vqs[rxq2vq(i)];
1386                 vi->sq[i].vq = vqs[txq2vq(i)];
1387         }
1388
1389         kfree(names);
1390         kfree(callbacks);
1391         kfree(vqs);
1392
1393         return 0;
1394
1395 err_find:
1396         kfree(names);
1397 err_names:
1398         kfree(callbacks);
1399 err_callback:
1400         kfree(vqs);
1401 err_vq:
1402         return ret;
1403 }
1404
1405 static int virtnet_alloc_queues(struct virtnet_info *vi)
1406 {
1407         int i;
1408
1409         vi->sq = kzalloc(sizeof(*vi->sq) * vi->max_queue_pairs, GFP_KERNEL);
1410         if (!vi->sq)
1411                 goto err_sq;
1412         vi->rq = kzalloc(sizeof(*vi->rq) * vi->max_queue_pairs, GFP_KERNEL);
1413         if (!vi->rq)
1414                 goto err_rq;
1415
1416         INIT_DELAYED_WORK(&vi->refill, refill_work);
1417         for (i = 0; i < vi->max_queue_pairs; i++) {
1418                 vi->rq[i].pages = NULL;
1419                 netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
1420                                napi_weight);
1421
1422                 sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
1423                 sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
1424         }
1425
1426         return 0;
1427
1428 err_rq:
1429         kfree(vi->sq);
1430 err_sq:
1431         return -ENOMEM;
1432 }
1433
1434 static int init_vqs(struct virtnet_info *vi)
1435 {
1436         int ret;
1437
1438         /* Allocate send & receive queues */
1439         ret = virtnet_alloc_queues(vi);
1440         if (ret)
1441                 goto err;
1442
1443         ret = virtnet_find_vqs(vi);
1444         if (ret)
1445                 goto err_free;
1446
1447         get_online_cpus();
1448         virtnet_set_affinity(vi);
1449         put_online_cpus();
1450
1451         return 0;
1452
1453 err_free:
1454         virtnet_free_queues(vi);
1455 err:
1456         return ret;
1457 }
1458
1459 static int virtnet_probe(struct virtio_device *vdev)
1460 {
1461         int i, err;
1462         struct net_device *dev;
1463         struct virtnet_info *vi;
1464         u16 max_queue_pairs;
1465
1466         /* Find if host supports multiqueue virtio_net device */
1467         err = virtio_config_val(vdev, VIRTIO_NET_F_MQ,
1468                                 offsetof(struct virtio_net_config,
1469                                 max_virtqueue_pairs), &max_queue_pairs);
1470
1471         /* We need at least 2 queue's */
1472         if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
1473             max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
1474             !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1475                 max_queue_pairs = 1;
1476
1477         /* Allocate ourselves a network device with room for our info */
1478         dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
1479         if (!dev)
1480                 return -ENOMEM;
1481
1482         /* Set up network device as normal. */
1483         dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE;
1484         dev->netdev_ops = &virtnet_netdev;
1485         dev->features = NETIF_F_HIGHDMA;
1486
1487         SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
1488         SET_NETDEV_DEV(dev, &vdev->dev);
1489
1490         /* Do we support "hardware" checksums? */
1491         if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
1492                 /* This opens up the world of extra features. */
1493                 dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1494                 if (csum)
1495                         dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1496
1497                 if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
1498                         dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
1499                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
1500                 }
1501                 /* Individual feature bits: what can host handle? */
1502                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
1503                         dev->hw_features |= NETIF_F_TSO;
1504                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
1505                         dev->hw_features |= NETIF_F_TSO6;
1506                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
1507                         dev->hw_features |= NETIF_F_TSO_ECN;
1508                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
1509                         dev->hw_features |= NETIF_F_UFO;
1510
1511                 if (gso)
1512                         dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
1513                 /* (!csum && gso) case will be fixed by register_netdev() */
1514         }
1515
1516         dev->vlan_features = dev->features;
1517
1518         /* Configuration may specify what MAC to use.  Otherwise random. */
1519         if (virtio_config_val_len(vdev, VIRTIO_NET_F_MAC,
1520                                   offsetof(struct virtio_net_config, mac),
1521                                   dev->dev_addr, dev->addr_len) < 0)
1522                 eth_hw_addr_random(dev);
1523
1524         /* Set up our device-specific information */
1525         vi = netdev_priv(dev);
1526         vi->dev = dev;
1527         vi->vdev = vdev;
1528         vdev->priv = vi;
1529         vi->stats = alloc_percpu(struct virtnet_stats);
1530         err = -ENOMEM;
1531         if (vi->stats == NULL)
1532                 goto free;
1533
1534         vi->vq_index = alloc_percpu(int);
1535         if (vi->vq_index == NULL)
1536                 goto free_stats;
1537
1538         mutex_init(&vi->config_lock);
1539         vi->config_enable = true;
1540         INIT_WORK(&vi->config_work, virtnet_config_changed_work);
1541
1542         /* If we can receive ANY GSO packets, we must allocate large ones. */
1543         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1544             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
1545             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
1546                 vi->big_packets = true;
1547
1548         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
1549                 vi->mergeable_rx_bufs = true;
1550
1551         if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1552                 vi->has_cvq = true;
1553
1554         /* Use single tx/rx queue pair as default */
1555         vi->curr_queue_pairs = 1;
1556         vi->max_queue_pairs = max_queue_pairs;
1557
1558         /* Allocate/initialize the rx/tx queues, and invoke find_vqs */
1559         err = init_vqs(vi);
1560         if (err)
1561                 goto free_index;
1562
1563         netif_set_real_num_tx_queues(dev, 1);
1564         netif_set_real_num_rx_queues(dev, 1);
1565
1566         err = register_netdev(dev);
1567         if (err) {
1568                 pr_debug("virtio_net: registering device failed\n");
1569                 goto free_vqs;
1570         }
1571
1572         /* Last of all, set up some receive buffers. */
1573         for (i = 0; i < vi->max_queue_pairs; i++) {
1574                 try_fill_recv(&vi->rq[i], GFP_KERNEL);
1575
1576                 /* If we didn't even get one input buffer, we're useless. */
1577                 if (vi->rq[i].num == 0) {
1578                         free_unused_bufs(vi);
1579                         err = -ENOMEM;
1580                         goto free_recv_bufs;
1581                 }
1582         }
1583
1584         vi->nb.notifier_call = &virtnet_cpu_callback;
1585         err = register_hotcpu_notifier(&vi->nb);
1586         if (err) {
1587                 pr_debug("virtio_net: registering cpu notifier failed\n");
1588                 goto free_recv_bufs;
1589         }
1590
1591         /* Assume link up if device can't report link status,
1592            otherwise get link status from config. */
1593         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1594                 netif_carrier_off(dev);
1595                 schedule_work(&vi->config_work);
1596         } else {
1597                 vi->status = VIRTIO_NET_S_LINK_UP;
1598                 netif_carrier_on(dev);
1599         }
1600
1601         pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
1602                  dev->name, max_queue_pairs);
1603
1604         return 0;
1605
1606 free_recv_bufs:
1607         free_receive_bufs(vi);
1608         unregister_netdev(dev);
1609 free_vqs:
1610         cancel_delayed_work_sync(&vi->refill);
1611         virtnet_del_vqs(vi);
1612 free_index:
1613         free_percpu(vi->vq_index);
1614 free_stats:
1615         free_percpu(vi->stats);
1616 free:
1617         free_netdev(dev);
1618         return err;
1619 }
1620
1621 static void remove_vq_common(struct virtnet_info *vi)
1622 {
1623         vi->vdev->config->reset(vi->vdev);
1624
1625         /* Free unused buffers in both send and recv, if any. */
1626         free_unused_bufs(vi);
1627
1628         free_receive_bufs(vi);
1629
1630         virtnet_del_vqs(vi);
1631 }
1632
1633 static void virtnet_remove(struct virtio_device *vdev)
1634 {
1635         struct virtnet_info *vi = vdev->priv;
1636
1637         unregister_hotcpu_notifier(&vi->nb);
1638
1639         /* Prevent config work handler from accessing the device. */
1640         mutex_lock(&vi->config_lock);
1641         vi->config_enable = false;
1642         mutex_unlock(&vi->config_lock);
1643
1644         unregister_netdev(vi->dev);
1645
1646         remove_vq_common(vi);
1647
1648         flush_work(&vi->config_work);
1649
1650         free_percpu(vi->vq_index);
1651         free_percpu(vi->stats);
1652         free_netdev(vi->dev);
1653 }
1654
1655 #ifdef CONFIG_PM
1656 static int virtnet_freeze(struct virtio_device *vdev)
1657 {
1658         struct virtnet_info *vi = vdev->priv;
1659         int i;
1660
1661         /* Prevent config work handler from accessing the device */
1662         mutex_lock(&vi->config_lock);
1663         vi->config_enable = false;
1664         mutex_unlock(&vi->config_lock);
1665
1666         netif_device_detach(vi->dev);
1667         cancel_delayed_work_sync(&vi->refill);
1668
1669         if (netif_running(vi->dev))
1670                 for (i = 0; i < vi->max_queue_pairs; i++) {
1671                         napi_disable(&vi->rq[i].napi);
1672                         netif_napi_del(&vi->rq[i].napi);
1673                 }
1674
1675         remove_vq_common(vi);
1676
1677         flush_work(&vi->config_work);
1678
1679         return 0;
1680 }
1681
1682 static int virtnet_restore(struct virtio_device *vdev)
1683 {
1684         struct virtnet_info *vi = vdev->priv;
1685         int err, i;
1686
1687         err = init_vqs(vi);
1688         if (err)
1689                 return err;
1690
1691         if (netif_running(vi->dev))
1692                 for (i = 0; i < vi->max_queue_pairs; i++)
1693                         virtnet_napi_enable(&vi->rq[i]);
1694
1695         netif_device_attach(vi->dev);
1696
1697         for (i = 0; i < vi->max_queue_pairs; i++)
1698                 if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
1699                         schedule_delayed_work(&vi->refill, 0);
1700
1701         mutex_lock(&vi->config_lock);
1702         vi->config_enable = true;
1703         mutex_unlock(&vi->config_lock);
1704
1705         virtnet_set_queues(vi, vi->curr_queue_pairs);
1706
1707         return 0;
1708 }
1709 #endif
1710
1711 static struct virtio_device_id id_table[] = {
1712         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1713         { 0 },
1714 };
1715
1716 static unsigned int features[] = {
1717         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1718         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1719         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
1720         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1721         VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
1722         VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
1723         VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
1724         VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
1725         VIRTIO_NET_F_CTRL_MAC_ADDR,
1726 };
1727
1728 static struct virtio_driver virtio_net_driver = {
1729         .feature_table = features,
1730         .feature_table_size = ARRAY_SIZE(features),
1731         .driver.name =  KBUILD_MODNAME,
1732         .driver.owner = THIS_MODULE,
1733         .id_table =     id_table,
1734         .probe =        virtnet_probe,
1735         .remove =       virtnet_remove,
1736         .config_changed = virtnet_config_changed,
1737 #ifdef CONFIG_PM
1738         .freeze =       virtnet_freeze,
1739         .restore =      virtnet_restore,
1740 #endif
1741 };
1742
1743 module_virtio_driver(virtio_net_driver);
1744
1745 MODULE_DEVICE_TABLE(virtio, id_table);
1746 MODULE_DESCRIPTION("Virtio network driver");
1747 MODULE_LICENSE("GPL");