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, see <http://www.gnu.org/licenses/>.
  17  */
  18 //#define DEBUG
  19 #include <linux/netdevice.h>
  20 #include <linux/etherdevice.h>
  21 #include <linux/ethtool.h>
  22 #include <linux/module.h>
  23 #include <linux/virtio.h>
  24 #include <linux/virtio_net.h>
  25 #include <linux/bpf.h>
  26 #include <linux/scatterlist.h>
  27 #include <linux/if_vlan.h>
  28 #include <linux/slab.h>
  29 #include <linux/cpu.h>
  30 #include <linux/average.h>
  31 #include <net/busy_poll.h>
  32
  33 static int napi_weight = NAPI_POLL_WEIGHT;
  34 module_param(napi_weight, int, 0444);
  35
  36 static bool csum = true, gso = true;
  37 module_param(csum, bool, 0444);
  38 module_param(gso, bool, 0444);
  39
  40 /* FIXME: MTU in config. */
  41 #define GOOD_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
  42 #define GOOD_COPY_LEN   128
  43
  44 /* RX packet size EWMA. The average packet size is used to determine the packet
  45  * buffer size when refilling RX rings. As the entire RX ring may be refilled
  46  * at once, the weight is chosen so that the EWMA will be insensitive to short-
  47  * term, transient changes in packet size.
  48  */
  49 DECLARE_EWMA(pkt_len, 1, 64)
  50
  51 /* Minimum alignment for mergeable packet buffers. */
  52 #define MERGEABLE_BUFFER_ALIGN max(L1_CACHE_BYTES, 256)
  53
  54 #define VIRTNET_DRIVER_VERSION "1.0.0"
  55
  56 struct virtnet_stats {
  57         struct u64_stats_sync tx_syncp;
  58         struct u64_stats_sync rx_syncp;
  59         u64 tx_bytes;
  60         u64 tx_packets;
  61
  62         u64 rx_bytes;
  63         u64 rx_packets;
  64 };
  65
  66 /* Internal representation of a send virtqueue */
  67 struct send_queue {
  68         /* Virtqueue associated with this send _queue */
  69         struct virtqueue *vq;
  70
  71         /* TX: fragments + linear part + virtio header */
  72         struct scatterlist sg[MAX_SKB_FRAGS + 2];
  73
  74         /* Name of the send queue: output.$index */
  75         char name[40];
  76 };
  77
  78 /* Internal representation of a receive virtqueue */
  79 struct receive_queue {
  80         /* Virtqueue associated with this receive_queue */
  81         struct virtqueue *vq;
  82
  83         struct napi_struct napi;
  84
  85         struct bpf_prog __rcu *xdp_prog;
  86
  87         /* Chain pages by the private ptr. */
  88         struct page *pages;
  89
  90         /* Average packet length for mergeable receive buffers. */
  91         struct ewma_pkt_len mrg_avg_pkt_len;
  92
  93         /* Page frag for packet buffer allocation. */
  94         struct page_frag alloc_frag;
  95
  96         /* RX: fragments + linear part + virtio header */
  97         struct scatterlist sg[MAX_SKB_FRAGS + 2];
  98
  99         /* Name of this receive queue: input.$index */
 100         char name[40];
 101 };
 102
 103 struct virtnet_info {
 104         struct virtio_device *vdev;
 105         struct virtqueue *cvq;
 106         struct net_device *dev;
 107         struct send_queue *sq;
 108         struct receive_queue *rq;
 109         unsigned int status;
 110
 111         /* Max # of queue pairs supported by the device */
 112         u16 max_queue_pairs;
 113
 114         /* # of queue pairs currently used by the driver */
 115         u16 curr_queue_pairs;
 116
 117         /* # of XDP queue pairs currently used by the driver */
 118         u16 xdp_queue_pairs;
 119
 120         /* I like... big packets and I cannot lie! */
 121         bool big_packets;
 122
 123         /* Host will merge rx buffers for big packets (shake it! shake it!) */
 124         bool mergeable_rx_bufs;
 125
 126         /* Has control virtqueue */
 127         bool has_cvq;
 128
 129         /* Host can handle any s/g split between our header and packet data */
 130         bool any_header_sg;
 131
 132         /* Packet virtio header size */
 133         u8 hdr_len;
 134
 135         /* Active statistics */
 136         struct virtnet_stats __percpu *stats;
 137
 138         /* Work struct for refilling if we run low on memory. */
 139         struct delayed_work refill;
 140
 141         /* Work struct for config space updates */
 142         struct work_struct config_work;
 143
 144         /* Does the affinity hint is set for virtqueues? */
 145         bool affinity_hint_set;
 146
 147         /* CPU hotplug instances for online & dead */
 148         struct hlist_node node;
 149         struct hlist_node node_dead;
 150
 151         /* Control VQ buffers: protected by the rtnl lock */
 152         struct virtio_net_ctrl_hdr ctrl_hdr;
 153         virtio_net_ctrl_ack ctrl_status;
 154         struct virtio_net_ctrl_mq ctrl_mq;
 155         u8 ctrl_promisc;
 156         u8 ctrl_allmulti;
 157         u16 ctrl_vid;
 158
 159         /* Ethtool settings */
 160         u8 duplex;
 161         u32 speed;
 162 };
 163
 164 struct padded_vnet_hdr {
 165         struct virtio_net_hdr_mrg_rxbuf hdr;
 166         /*
 167          * hdr is in a separate sg buffer, and data sg buffer shares same page
 168          * with this header sg. This padding makes next sg 16 byte aligned
 169          * after the header.
 170          */
 171         char padding[4];
 172 };
 173
 174 /* Converting between virtqueue no. and kernel tx/rx queue no.
 175  * 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq
 176  */
 177 static int vq2txq(struct virtqueue *vq)
 178 {
 179         return (vq->index - 1) / 2;
 180 }
 181
 182 static int txq2vq(int txq)
 183 {
 184         return txq * 2 + 1;
 185 }
 186
 187 static int vq2rxq(struct virtqueue *vq)
 188 {
 189         return vq->index / 2;
 190 }
 191
 192 static int rxq2vq(int rxq)
 193 {
 194         return rxq * 2;
 195 }
 196
 197 static inline struct virtio_net_hdr_mrg_rxbuf *skb_vnet_hdr(struct sk_buff *skb)
 198 {
 199         return (struct virtio_net_hdr_mrg_rxbuf *)skb->cb;
 200 }
 201
 202 /*
 203  * private is used to chain pages for big packets, put the whole
 204  * most recent used list in the beginning for reuse
 205  */
 206 static void give_pages(struct receive_queue *rq, struct page *page)
 207 {
 208         struct page *end;
 209
 210         /* Find end of list, sew whole thing into vi->rq.pages. */
 211         for (end = page; end->private; end = (struct page *)end->private);
 212         end->private = (unsigned long)rq->pages;
 213         rq->pages = page;
 214 }
 215
 216 static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
 217 {
 218         struct page *p = rq->pages;
 219
 220         if (p) {
 221                 rq->pages = (struct page *)p->private;
 222                 /* clear private here, it is used to chain pages */
 223                 p->private = 0;
 224         } else
 225                 p = alloc_page(gfp_mask);
 226         return p;
 227 }
 228
 229 static void skb_xmit_done(struct virtqueue *vq)
 230 {
 231         struct virtnet_info *vi = vq->vdev->priv;
 232
 233         /* Suppress further interrupts. */
 234         virtqueue_disable_cb(vq);
 235
 236         /* We were probably waiting for more output buffers. */
 237         netif_wake_subqueue(vi->dev, vq2txq(vq));
 238 }
 239
 240 static unsigned int mergeable_ctx_to_buf_truesize(unsigned long mrg_ctx)
 241 {
 242         unsigned int truesize = mrg_ctx & (MERGEABLE_BUFFER_ALIGN - 1);
 243         return (truesize + 1) * MERGEABLE_BUFFER_ALIGN;
 244 }
 245
 246 static void *mergeable_ctx_to_buf_address(unsigned long mrg_ctx)
 247 {
 248         return (void *)(mrg_ctx & -MERGEABLE_BUFFER_ALIGN);
 249
 250 }
 251
 252 static unsigned long mergeable_buf_to_ctx(void *buf, unsigned int truesize)
 253 {
 254         unsigned int size = truesize / MERGEABLE_BUFFER_ALIGN;
 255         return (unsigned long)buf | (size - 1);
 256 }
 257
 258 /* Called from bottom half context */
 259 static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 260                                    struct receive_queue *rq,
 261                                    struct page *page, unsigned int offset,
 262                                    unsigned int len, unsigned int truesize)
 263 {
 264         struct sk_buff *skb;
 265         struct virtio_net_hdr_mrg_rxbuf *hdr;
 266         unsigned int copy, hdr_len, hdr_padded_len;
 267         char *p;
 268
 269         p = page_address(page) + offset;
 270
 271         /* copy small packet so we can reuse these pages for small data */
 272         skb = napi_alloc_skb(&rq->napi, GOOD_COPY_LEN);
 273         if (unlikely(!skb))
 274                 return NULL;
 275
 276         hdr = skb_vnet_hdr(skb);
 277
 278         hdr_len = vi->hdr_len;
 279         if (vi->mergeable_rx_bufs)
 280                 hdr_padded_len = sizeof *hdr;
 281         else
 282                 hdr_padded_len = sizeof(struct padded_vnet_hdr);
 283
 284         memcpy(hdr, p, hdr_len);
 285
 286         len -= hdr_len;
 287         offset += hdr_padded_len;
 288         p += hdr_padded_len;
 289
 290         copy = len;
 291         if (copy > skb_tailroom(skb))
 292                 copy = skb_tailroom(skb);
 293         memcpy(skb_put(skb, copy), p, copy);
 294
 295         len -= copy;
 296         offset += copy;
 297
 298         if (vi->mergeable_rx_bufs) {
 299                 if (len)
 300                         skb_add_rx_frag(skb, 0, page, offset, len, truesize);
 301                 else
 302                         put_page(page);
 303                 return skb;
 304         }
 305
 306         /*
 307          * Verify that we can indeed put this data into a skb.
 308          * This is here to handle cases when the device erroneously
 309          * tries to receive more than is possible. This is usually
 310          * the case of a broken device.
 311          */
 312         if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
 313                 net_dbg_ratelimited("%s: too much data\n", skb->dev->name);
 314                 dev_kfree_skb(skb);
 315                 return NULL;
 316         }
 317         BUG_ON(offset >= PAGE_SIZE);
 318         while (len) {
 319                 unsigned int frag_size = min((unsigned)PAGE_SIZE - offset, len);
 320                 skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, offset,
 321                                 frag_size, truesize);
 322                 len -= frag_size;
 323                 page = (struct page *)page->private;
 324                 offset = 0;
 325         }
 326
 327         if (page)
 328                 give_pages(rq, page);
 329
 330         return skb;
 331 }
 332
 333 static void virtnet_xdp_xmit(struct virtnet_info *vi,
 334                              struct receive_queue *rq,
 335                              struct send_queue *sq,
 336                              struct xdp_buff *xdp)
 337 {
 338         struct page *page = virt_to_head_page(xdp->data);
 339         struct virtio_net_hdr_mrg_rxbuf *hdr;
 340         unsigned int num_sg, len;
 341         void *xdp_sent;
 342         int err;
 343
 344         /* Free up any pending old buffers before queueing new ones. */
 345         while ((xdp_sent = virtqueue_get_buf(sq->vq, &len)) != NULL) {
 346                 struct page *sent_page = virt_to_head_page(xdp_sent);
 347
 348                 if (vi->mergeable_rx_bufs)
 349                         put_page(sent_page);
 350                 else
 351                         give_pages(rq, sent_page);
 352         }
 353
 354         /* Zero header and leave csum up to XDP layers */
 355         hdr = xdp->data;
 356         memset(hdr, 0, vi->hdr_len);
 357
 358         num_sg = 1;
 359         sg_init_one(sq->sg, xdp->data, xdp->data_end - xdp->data);
 360         err = virtqueue_add_outbuf(sq->vq, sq->sg, num_sg,
 361                                    xdp->data, GFP_ATOMIC);
 362         if (unlikely(err)) {
 363                 if (vi->mergeable_rx_bufs)
 364                         put_page(page);
 365                 else
 366                         give_pages(rq, page);
 367                 return; // On error abort to avoid unnecessary kick
 368         } else if (!vi->mergeable_rx_bufs) {
 369                 /* If not mergeable bufs must be big packets so cleanup pages */
 370                 give_pages(rq, (struct page *)page->private);
 371                 page->private = 0;
 372         }
 373
 374         virtqueue_kick(sq->vq);
 375 }
 376
 377 static u32 do_xdp_prog(struct virtnet_info *vi,
 378                        struct receive_queue *rq,
 379                        struct bpf_prog *xdp_prog,
 380                        struct page *page, int offset, int len)
 381 {
 382         int hdr_padded_len;
 383         struct xdp_buff xdp;
 384         unsigned int qp;
 385         u32 act;
 386         u8 *buf;
 387
 388         buf = page_address(page) + offset;
 389
 390         if (vi->mergeable_rx_bufs)
 391                 hdr_padded_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
 392         else
 393                 hdr_padded_len = sizeof(struct padded_vnet_hdr);
 394
 395         xdp.data = buf + hdr_padded_len;
 396         xdp.data_end = xdp.data + (len - vi->hdr_len);
 397
 398         act = bpf_prog_run_xdp(xdp_prog, &xdp);
 399         switch (act) {
 400         case XDP_PASS:
 401                 return XDP_PASS;
 402         case XDP_TX:
 403                 qp = vi->curr_queue_pairs -
 404                         vi->xdp_queue_pairs +
 405                         smp_processor_id();
 406                 xdp.data = buf + (vi->mergeable_rx_bufs ? 0 : 4);
 407                 virtnet_xdp_xmit(vi, rq, &vi->sq[qp], &xdp);
 408                 return XDP_TX;
 409         default:
 410                 bpf_warn_invalid_xdp_action(act);
 411         case XDP_ABORTED:
 412         case XDP_DROP:
 413                 return XDP_DROP;
 414         }
 415 }
 416
 417 static struct sk_buff *receive_small(struct virtnet_info *vi, void *buf, unsigned int len)
 418 {
 419         struct sk_buff * skb = buf;
 420
 421         len -= vi->hdr_len;
 422         skb_trim(skb, len);
 423
 424         return skb;
 425 }
 426
 427 static struct sk_buff *receive_big(struct net_device *dev,
 428                                    struct virtnet_info *vi,
 429                                    struct receive_queue *rq,
 430                                    void *buf,
 431                                    unsigned int len)
 432 {
 433         struct bpf_prog *xdp_prog;
 434         struct page *page = buf;
 435         struct sk_buff *skb;
 436
 437         rcu_read_lock();
 438         xdp_prog = rcu_dereference(rq->xdp_prog);
 439         if (xdp_prog) {
 440                 struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
 441                 u32 act;
 442
 443                 if (unlikely(hdr->hdr.gso_type || hdr->hdr.flags))
 444                         goto err_xdp;
 445                 act = do_xdp_prog(vi, rq, xdp_prog, page, 0, len);
 446                 switch (act) {
 447                 case XDP_PASS:
 448                         break;
 449                 case XDP_TX:
 450                         rcu_read_unlock();
 451                         goto xdp_xmit;
 452                 case XDP_DROP:
 453                 default:
 454                         goto err_xdp;
 455                 }
 456         }
 457         rcu_read_unlock();
 458
 459         skb = page_to_skb(vi, rq, page, 0, len, PAGE_SIZE);
 460         if (unlikely(!skb))
 461                 goto err;
 462
 463         return skb;
 464
 465 err_xdp:
 466         rcu_read_unlock();
 467 err:
 468         dev->stats.rx_dropped++;
 469         give_pages(rq, page);
 470 xdp_xmit:
 471         return NULL;
 472 }
 473
 474 /* The conditions to enable XDP should preclude the underlying device from
 475  * sending packets across multiple buffers (num_buf > 1). However per spec
 476  * it does not appear to be illegal to do so but rather just against convention.
 477  * So in order to avoid making a system unresponsive the packets are pushed
 478  * into a page and the XDP program is run. This will be extremely slow and we
 479  * push a warning to the user to fix this as soon as possible. Fixing this may
 480  * require resolving the underlying hardware to determine why multiple buffers
 481  * are being received or simply loading the XDP program in the ingress stack
 482  * after the skb is built because there is no advantage to running it here
 483  * anymore.
 484  */
 485 static struct page *xdp_linearize_page(struct receive_queue *rq,
 486                                        u16 num_buf,
 487                                        struct page *p,
 488                                        int offset,
 489                                        unsigned int *len)
 490 {
 491         struct page *page = alloc_page(GFP_ATOMIC);
 492         unsigned int page_off = 0;
 493
 494         if (!page)
 495                 return NULL;
 496
 497         memcpy(page_address(page) + page_off, page_address(p) + offset, *len);
 498         page_off += *len;
 499
 500         while (--num_buf) {
 501                 unsigned int buflen;
 502                 unsigned long ctx;
 503                 void *buf;
 504                 int off;
 505
 506                 ctx = (unsigned long)virtqueue_get_buf(rq->vq, &buflen);
 507                 if (unlikely(!ctx))
 508                         goto err_buf;
 509
 510                 /* guard against a misconfigured or uncooperative backend that
 511                  * is sending packet larger than the MTU.
 512                  */
 513                 if ((page_off + buflen) > PAGE_SIZE)
 514                         goto err_buf;
 515
 516                 buf = mergeable_ctx_to_buf_address(ctx);
 517                 p = virt_to_head_page(buf);
 518                 off = buf - page_address(p);
 519
 520                 memcpy(page_address(page) + page_off,
 521                        page_address(p) + off, buflen);
 522                 page_off += buflen;
 523         }
 524
 525         *len = page_off;
 526         return page;
 527 err_buf:
 528         __free_pages(page, 0);
 529         return NULL;
 530 }
 531
 532 static struct sk_buff *receive_mergeable(struct net_device *dev,
 533                                          struct virtnet_info *vi,
 534                                          struct receive_queue *rq,
 535                                          unsigned long ctx,
 536                                          unsigned int len)
 537 {
 538         void *buf = mergeable_ctx_to_buf_address(ctx);
 539         struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
 540         u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
 541         struct page *page = virt_to_head_page(buf);
 542         int offset = buf - page_address(page);
 543         struct sk_buff *head_skb, *curr_skb;
 544         struct bpf_prog *xdp_prog;
 545         unsigned int truesize;
 546
 547         head_skb = NULL;
 548
 549         rcu_read_lock();
 550         xdp_prog = rcu_dereference(rq->xdp_prog);
 551         if (xdp_prog) {
 552                 struct page *xdp_page;
 553                 u32 act;
 554
 555                 /* This happens when rx buffer size is underestimated */
 556                 if (unlikely(num_buf > 1)) {
 557                         /* linearize data for XDP */
 558                         xdp_page = xdp_linearize_page(rq, num_buf,
 559                                                       page, offset, &len);
 560                         if (!xdp_page)
 561                                 goto err_xdp;
 562                         offset = 0;
 563                 } else {
 564                         xdp_page = page;
 565                 }
 566
 567                 /* Transient failure which in theory could occur if
 568                  * in-flight packets from before XDP was enabled reach
 569                  * the receive path after XDP is loaded. In practice I
 570                  * was not able to create this condition.
 571                  */
 572                 if (unlikely(hdr->hdr.gso_type || hdr->hdr.flags))
 573                         goto err_xdp;
 574
 575                 act = do_xdp_prog(vi, rq, xdp_prog, page, offset, len);
 576                 switch (act) {
 577                 case XDP_PASS:
 578                         if (unlikely(xdp_page != page))
 579                                 __free_pages(xdp_page, 0);
 580                         break;
 581                 case XDP_TX:
 582                         if (unlikely(xdp_page != page))
 583                                 goto err_xdp;
 584                         rcu_read_unlock();
 585                         goto xdp_xmit;
 586                 case XDP_DROP:
 587                 default:
 588                         if (unlikely(xdp_page != page))
 589                                 __free_pages(xdp_page, 0);
 590                         goto err_xdp;
 591                 }
 592         }
 593         rcu_read_unlock();
 594
 595         truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
 596         head_skb = page_to_skb(vi, rq, page, offset, len, truesize);
 597         curr_skb = head_skb;
 598
 599         if (unlikely(!curr_skb))
 600                 goto err_skb;
 601         while (--num_buf) {
 602                 int num_skb_frags;
 603
 604                 ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
 605                 if (unlikely(!ctx)) {
 606                         pr_debug("%s: rx error: %d buffers out of %d missing\n",
 607                                  dev->name, num_buf,
 608                                  virtio16_to_cpu(vi->vdev,
 609                                                  hdr->num_buffers));
 610                         dev->stats.rx_length_errors++;
 611                         goto err_buf;
 612                 }
 613
 614                 buf = mergeable_ctx_to_buf_address(ctx);
 615                 page = virt_to_head_page(buf);
 616
 617                 num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
 618                 if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
 619                         struct sk_buff *nskb = alloc_skb(0, GFP_ATOMIC);
 620
 621                         if (unlikely(!nskb))
 622                                 goto err_skb;
 623                         if (curr_skb == head_skb)
 624                                 skb_shinfo(curr_skb)->frag_list = nskb;
 625                         else
 626                                 curr_skb->next = nskb;
 627                         curr_skb = nskb;
 628                         head_skb->truesize += nskb->truesize;
 629                         num_skb_frags = 0;
 630                 }
 631                 truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
 632                 if (curr_skb != head_skb) {
 633                         head_skb->data_len += len;
 634                         head_skb->len += len;
 635                         head_skb->truesize += truesize;
 636                 }
 637                 offset = buf - page_address(page);
 638                 if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
 639                         put_page(page);
 640                         skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
 641                                              len, truesize);
 642                 } else {
 643                         skb_add_rx_frag(curr_skb, num_skb_frags, page,
 644                                         offset, len, truesize);
 645                 }
 646         }
 647
 648         ewma_pkt_len_add(&rq->mrg_avg_pkt_len, head_skb->len);
 649         return head_skb;
 650
 651 err_xdp:
 652         rcu_read_unlock();
 653 err_skb:
 654         put_page(page);
 655         while (--num_buf) {
 656                 ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
 657                 if (unlikely(!ctx)) {
 658                         pr_debug("%s: rx error: %d buffers missing\n",
 659                                  dev->name, num_buf);
 660                         dev->stats.rx_length_errors++;
 661                         break;
 662                 }
 663                 page = virt_to_head_page(mergeable_ctx_to_buf_address(ctx));
 664                 put_page(page);
 665         }
 666 err_buf:
 667         dev->stats.rx_dropped++;
 668         dev_kfree_skb(head_skb);
 669 xdp_xmit:
 670         return NULL;
 671 }
 672
 673 static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
 674                         void *buf, unsigned int len)
 675 {
 676         struct net_device *dev = vi->dev;
 677         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
 678         struct sk_buff *skb;
 679         struct virtio_net_hdr_mrg_rxbuf *hdr;
 680
 681         if (unlikely(len < vi->hdr_len + ETH_HLEN)) {
 682                 pr_debug("%s: short packet %i\n", dev->name, len);
 683                 dev->stats.rx_length_errors++;
 684                 if (vi->mergeable_rx_bufs) {
 685                         unsigned long ctx = (unsigned long)buf;
 686                         void *base = mergeable_ctx_to_buf_address(ctx);
 687                         put_page(virt_to_head_page(base));
 688                 } else if (vi->big_packets) {
 689                         give_pages(rq, buf);
 690                 } else {
 691                         dev_kfree_skb(buf);
 692                 }
 693                 return;
 694         }
 695
 696         if (vi->mergeable_rx_bufs)
 697                 skb = receive_mergeable(dev, vi, rq, (unsigned long)buf, len);
 698         else if (vi->big_packets)
 699                 skb = receive_big(dev, vi, rq, buf, len);
 700         else
 701                 skb = receive_small(vi, buf, len);
 702
 703         if (unlikely(!skb))
 704                 return;
 705
 706         hdr = skb_vnet_hdr(skb);
 707
 708         u64_stats_update_begin(&stats->rx_syncp);
 709         stats->rx_bytes += skb->len;
 710         stats->rx_packets++;
 711         u64_stats_update_end(&stats->rx_syncp);
 712
 713         if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID)
 714                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 715
 716         if (virtio_net_hdr_to_skb(skb, &hdr->hdr,
 717                                   virtio_is_little_endian(vi->vdev))) {
 718                 net_warn_ratelimited("%s: bad gso: type: %u, size: %u\n",
 719                                      dev->name, hdr->hdr.gso_type,
 720                                      hdr->hdr.gso_size);
 721                 goto frame_err;
 722         }
 723
 724         skb->protocol = eth_type_trans(skb, dev);
 725         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
 726                  ntohs(skb->protocol), skb->len, skb->pkt_type);
 727
 728         napi_gro_receive(&rq->napi, skb);
 729         return;
 730
 731 frame_err:
 732         dev->stats.rx_frame_errors++;
 733         dev_kfree_skb(skb);
 734 }
 735
 736 static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
 737                              gfp_t gfp)
 738 {
 739         struct sk_buff *skb;
 740         struct virtio_net_hdr_mrg_rxbuf *hdr;
 741         int err;
 742
 743         skb = __netdev_alloc_skb_ip_align(vi->dev, GOOD_PACKET_LEN, gfp);
 744         if (unlikely(!skb))
 745                 return -ENOMEM;
 746
 747         skb_put(skb, GOOD_PACKET_LEN);
 748
 749         hdr = skb_vnet_hdr(skb);
 750         sg_init_table(rq->sg, 2);
 751         sg_set_buf(rq->sg, hdr, vi->hdr_len);
 752         skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
 753
 754         err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp);
 755         if (err < 0)
 756                 dev_kfree_skb(skb);
 757
 758         return err;
 759 }
 760
 761 static int add_recvbuf_big(struct virtnet_info *vi, struct receive_queue *rq,
 762                            gfp_t gfp)
 763 {
 764         struct page *first, *list = NULL;
 765         char *p;
 766         int i, err, offset;
 767
 768         sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
 769
 770         /* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */
 771         for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
 772                 first = get_a_page(rq, gfp);
 773                 if (!first) {
 774                         if (list)
 775                                 give_pages(rq, list);
 776                         return -ENOMEM;
 777                 }
 778                 sg_set_buf(&rq->sg[i], page_address(first), PAGE_SIZE);
 779
 780                 /* chain new page in list head to match sg */
 781                 first->private = (unsigned long)list;
 782                 list = first;
 783         }
 784
 785         first = get_a_page(rq, gfp);
 786         if (!first) {
 787                 give_pages(rq, list);
 788                 return -ENOMEM;
 789         }
 790         p = page_address(first);
 791
 792         /* rq->sg[0], rq->sg[1] share the same page */
 793         /* a separated rq->sg[0] for header - required in case !any_header_sg */
 794         sg_set_buf(&rq->sg[0], p, vi->hdr_len);
 795
 796         /* rq->sg[1] for data packet, from offset */
 797         offset = sizeof(struct padded_vnet_hdr);
 798         sg_set_buf(&rq->sg[1], p + offset, PAGE_SIZE - offset);
 799
 800         /* chain first in list head */
 801         first->private = (unsigned long)list;
 802         err = virtqueue_add_inbuf(rq->vq, rq->sg, MAX_SKB_FRAGS + 2,
 803                                   first, gfp);
 804         if (err < 0)
 805                 give_pages(rq, first);
 806
 807         return err;
 808 }
 809
 810 static unsigned int get_mergeable_buf_len(struct ewma_pkt_len *avg_pkt_len)
 811 {
 812         const size_t hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
 813         unsigned int len;
 814
 815         len = hdr_len + clamp_t(unsigned int, ewma_pkt_len_read(avg_pkt_len),
 816                         GOOD_PACKET_LEN, PAGE_SIZE - hdr_len);
 817         return ALIGN(len, MERGEABLE_BUFFER_ALIGN);
 818 }
 819
 820 static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
 821 {
 822         struct page_frag *alloc_frag = &rq->alloc_frag;
 823         char *buf;
 824         unsigned long ctx;
 825         int err;
 826         unsigned int len, hole;
 827
 828         len = get_mergeable_buf_len(&rq->mrg_avg_pkt_len);
 829         if (unlikely(!skb_page_frag_refill(len, alloc_frag, gfp)))
 830                 return -ENOMEM;
 831
 832         buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
 833         ctx = mergeable_buf_to_ctx(buf, len);
 834         get_page(alloc_frag->page);
 835         alloc_frag->offset += len;
 836         hole = alloc_frag->size - alloc_frag->offset;
 837         if (hole < len) {
 838                 /* To avoid internal fragmentation, if there is very likely not
 839                  * enough space for another buffer, add the remaining space to
 840                  * the current buffer. This extra space is not included in
 841                  * the truesize stored in ctx.
 842                  */
 843                 len += hole;
 844                 alloc_frag->offset += hole;
 845         }
 846
 847         sg_init_one(rq->sg, buf, len);
 848         err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, (void *)ctx, gfp);
 849         if (err < 0)
 850                 put_page(virt_to_head_page(buf));
 851
 852         return err;
 853 }
 854
 855 /*
 856  * Returns false if we couldn't fill entirely (OOM).
 857  *
 858  * Normally run in the receive path, but can also be run from ndo_open
 859  * before we're receiving packets, or from refill_work which is
 860  * careful to disable receiving (using napi_disable).
 861  */
 862 static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
 863                           gfp_t gfp)
 864 {
 865         int err;
 866         bool oom;
 867
 868         gfp |= __GFP_COLD;
 869         do {
 870                 if (vi->mergeable_rx_bufs)
 871                         err = add_recvbuf_mergeable(rq, gfp);
 872                 else if (vi->big_packets)
 873                         err = add_recvbuf_big(vi, rq, gfp);
 874                 else
 875                         err = add_recvbuf_small(vi, rq, gfp);
 876
 877                 oom = err == -ENOMEM;
 878                 if (err)
 879                         break;
 880         } while (rq->vq->num_free);
 881         virtqueue_kick(rq->vq);
 882         return !oom;
 883 }
 884
 885 static void skb_recv_done(struct virtqueue *rvq)
 886 {
 887         struct virtnet_info *vi = rvq->vdev->priv;
 888         struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
 889
 890         /* Schedule NAPI, Suppress further interrupts if successful. */
 891         if (napi_schedule_prep(&rq->napi)) {
 892                 virtqueue_disable_cb(rvq);
 893                 __napi_schedule(&rq->napi);
 894         }
 895 }
 896
 897 static void virtnet_napi_enable(struct receive_queue *rq)
 898 {
 899         napi_enable(&rq->napi);
 900
 901         /* If all buffers were filled by other side before we napi_enabled, we
 902          * won't get another interrupt, so process any outstanding packets
 903          * now.  virtnet_poll wants re-enable the queue, so we disable here.
 904          * We synchronize against interrupts via NAPI_STATE_SCHED */
 905         if (napi_schedule_prep(&rq->napi)) {
 906                 virtqueue_disable_cb(rq->vq);
 907                 local_bh_disable();
 908                 __napi_schedule(&rq->napi);
 909                 local_bh_enable();
 910         }
 911 }
 912
 913 static void refill_work(struct work_struct *work)
 914 {
 915         struct virtnet_info *vi =
 916                 container_of(work, struct virtnet_info, refill.work);
 917         bool still_empty;
 918         int i;
 919
 920         for (i = 0; i < vi->curr_queue_pairs; i++) {
 921                 struct receive_queue *rq = &vi->rq[i];
 922
 923                 napi_disable(&rq->napi);
 924                 still_empty = !try_fill_recv(vi, rq, GFP_KERNEL);
 925                 virtnet_napi_enable(rq);
 926
 927                 /* In theory, this can happen: if we don't get any buffers in
 928                  * we will *never* try to fill again.
 929                  */
 930                 if (still_empty)
 931                         schedule_delayed_work(&vi->refill, HZ/2);
 932         }
 933 }
 934
 935 static int virtnet_receive(struct receive_queue *rq, int budget)
 936 {
 937         struct virtnet_info *vi = rq->vq->vdev->priv;
 938         unsigned int len, received = 0;
 939         void *buf;
 940
 941         while (received < budget &&
 942                (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
 943                 receive_buf(vi, rq, buf, len);
 944                 received++;
 945         }
 946
 947         if (rq->vq->num_free > virtqueue_get_vring_size(rq->vq) / 2) {
 948                 if (!try_fill_recv(vi, rq, GFP_ATOMIC))
 949                         schedule_delayed_work(&vi->refill, 0);
 950         }
 951
 952         return received;
 953 }
 954
 955 static int virtnet_poll(struct napi_struct *napi, int budget)
 956 {
 957         struct receive_queue *rq =
 958                 container_of(napi, struct receive_queue, napi);
 959         unsigned int r, received;
 960
 961         received = virtnet_receive(rq, budget);
 962
 963         /* Out of packets? */
 964         if (received < budget) {
 965                 r = virtqueue_enable_cb_prepare(rq->vq);
 966                 napi_complete_done(napi, received);
 967                 if (unlikely(virtqueue_poll(rq->vq, r)) &&
 968                     napi_schedule_prep(napi)) {
 969                         virtqueue_disable_cb(rq->vq);
 970                         __napi_schedule(napi);
 971                 }
 972         }
 973
 974         return received;
 975 }
 976
 977 #ifdef CONFIG_NET_RX_BUSY_POLL
 978 /* must be called with local_bh_disable()d */
 979 static int virtnet_busy_poll(struct napi_struct *napi)
 980 {
 981         struct receive_queue *rq =
 982                 container_of(napi, struct receive_queue, napi);
 983         struct virtnet_info *vi = rq->vq->vdev->priv;
 984         int r, received = 0, budget = 4;
 985
 986         if (!(vi->status & VIRTIO_NET_S_LINK_UP))
 987                 return LL_FLUSH_FAILED;
 988
 989         if (!napi_schedule_prep(napi))
 990                 return LL_FLUSH_BUSY;
 991
 992         virtqueue_disable_cb(rq->vq);
 993
 994 again:
 995         received += virtnet_receive(rq, budget);
 996
 997         r = virtqueue_enable_cb_prepare(rq->vq);
 998         clear_bit(NAPI_STATE_SCHED, &napi->state);
 999         if (unlikely(virtqueue_poll(rq->vq, r)) &&
1000             napi_schedule_prep(napi)) {
1001                 virtqueue_disable_cb(rq->vq);
1002                 if (received < budget) {
1003                         budget -= received;
1004                         goto again;
1005                 } else {
1006                         __napi_schedule(napi);
1007                 }
1008         }
1009
1010         return received;
1011 }
1012 #endif  /* CONFIG_NET_RX_BUSY_POLL */
1013
1014 static int virtnet_open(struct net_device *dev)
1015 {
1016         struct virtnet_info *vi = netdev_priv(dev);
1017         int i;
1018
1019         for (i = 0; i < vi->max_queue_pairs; i++) {
1020                 if (i < vi->curr_queue_pairs)
1021                         /* Make sure we have some buffers: if oom use wq. */
1022                         if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
1023                                 schedule_delayed_work(&vi->refill, 0);
1024                 virtnet_napi_enable(&vi->rq[i]);
1025         }
1026
1027         return 0;
1028 }
1029
1030 static void free_old_xmit_skbs(struct send_queue *sq)
1031 {
1032         struct sk_buff *skb;
1033         unsigned int len;
1034         struct virtnet_info *vi = sq->vq->vdev->priv;
1035         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
1036
1037         while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {
1038                 pr_debug("Sent skb %p\n", skb);
1039
1040                 u64_stats_update_begin(&stats->tx_syncp);
1041                 stats->tx_bytes += skb->len;
1042                 stats->tx_packets++;
1043                 u64_stats_update_end(&stats->tx_syncp);
1044
1045                 dev_kfree_skb_any(skb);
1046         }
1047 }
1048
1049 static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
1050 {
1051         struct virtio_net_hdr_mrg_rxbuf *hdr;
1052         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
1053         struct virtnet_info *vi = sq->vq->vdev->priv;
1054         unsigned num_sg;
1055         unsigned hdr_len = vi->hdr_len;
1056         bool can_push;
1057
1058         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
1059
1060         can_push = vi->any_header_sg &&
1061                 !((unsigned long)skb->data & (__alignof__(*hdr) - 1)) &&
1062                 !skb_header_cloned(skb) && skb_headroom(skb) >= hdr_len;
1063         /* Even if we can, don't push here yet as this would skew
1064          * csum_start offset below. */
1065         if (can_push)
1066                 hdr = (struct virtio_net_hdr_mrg_rxbuf *)(skb->data - hdr_len);
1067         else
1068                 hdr = skb_vnet_hdr(skb);
1069
1070         if (virtio_net_hdr_from_skb(skb, &hdr->hdr,
1071                                     virtio_is_little_endian(vi->vdev)))
1072                 BUG();
1073
1074         if (vi->mergeable_rx_bufs)
1075                 hdr->num_buffers = 0;
1076
1077         sg_init_table(sq->sg, skb_shinfo(skb)->nr_frags + (can_push ? 1 : 2));
1078         if (can_push) {
1079                 __skb_push(skb, hdr_len);
1080                 num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len);
1081                 /* Pull header back to avoid skew in tx bytes calculations. */
1082                 __skb_pull(skb, hdr_len);
1083         } else {
1084                 sg_set_buf(sq->sg, hdr, hdr_len);
1085                 num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
1086         }
1087         return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC);
1088 }
1089
1090 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
1091 {
1092         struct virtnet_info *vi = netdev_priv(dev);
1093         int qnum = skb_get_queue_mapping(skb);
1094         struct send_queue *sq = &vi->sq[qnum];
1095         int err;
1096         struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum);
1097         bool kick = !skb->xmit_more;
1098
1099         /* Free up any pending old buffers before queueing new ones. */
1100         free_old_xmit_skbs(sq);
1101
1102         /* timestamp packet in software */
1103         skb_tx_timestamp(skb);
1104
1105         /* Try to transmit */
1106         err = xmit_skb(sq, skb);
1107
1108         /* This should not happen! */
1109         if (unlikely(err)) {
1110                 dev->stats.tx_fifo_errors++;
1111                 if (net_ratelimit())
1112                         dev_warn(&dev->dev,
1113                                  "Unexpected TXQ (%d) queue failure: %d\n", qnum, err);
1114                 dev->stats.tx_dropped++;
1115                 dev_kfree_skb_any(skb);
1116                 return NETDEV_TX_OK;
1117         }
1118
1119         /* Don't wait up for transmitted skbs to be freed. */
1120         skb_orphan(skb);
1121         nf_reset(skb);
1122
1123         /* If running out of space, stop queue to avoid getting packets that we
1124          * are then unable to transmit.
1125          * An alternative would be to force queuing layer to requeue the skb by
1126          * returning NETDEV_TX_BUSY. However, NETDEV_TX_BUSY should not be
1127          * returned in a normal path of operation: it means that driver is not
1128          * maintaining the TX queue stop/start state properly, and causes
1129          * the stack to do a non-trivial amount of useless work.
1130          * Since most packets only take 1 or 2 ring slots, stopping the queue
1131          * early means 16 slots are typically wasted.
1132          */
1133         if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
1134                 netif_stop_subqueue(dev, qnum);
1135                 if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
1136                         /* More just got used, free them then recheck. */
1137                         free_old_xmit_skbs(sq);
1138                         if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
1139                                 netif_start_subqueue(dev, qnum);
1140                                 virtqueue_disable_cb(sq->vq);
1141                         }
1142                 }
1143         }
1144
1145         if (kick || netif_xmit_stopped(txq))
1146                 virtqueue_kick(sq->vq);
1147
1148         return NETDEV_TX_OK;
1149 }
1150
1151 /*
1152  * Send command via the control virtqueue and check status.  Commands
1153  * supported by the hypervisor, as indicated by feature bits, should
1154  * never fail unless improperly formatted.
1155  */
1156 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
1157                                  struct scatterlist *out)
1158 {
1159         struct scatterlist *sgs[4], hdr, stat;
1160         unsigned out_num = 0, tmp;
1161
1162         /* Caller should know better */
1163         BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
1164
1165         vi->ctrl_status = ~0;
1166         vi->ctrl_hdr.class = class;
1167         vi->ctrl_hdr.cmd = cmd;
1168         /* Add header */
1169         sg_init_one(&hdr, &vi->ctrl_hdr, sizeof(vi->ctrl_hdr));
1170         sgs[out_num++] = &hdr;
1171
1172         if (out)
1173                 sgs[out_num++] = out;
1174
1175         /* Add return status. */
1176         sg_init_one(&stat, &vi->ctrl_status, sizeof(vi->ctrl_status));
1177         sgs[out_num] = &stat;
1178
1179         BUG_ON(out_num + 1 > ARRAY_SIZE(sgs));
1180         virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
1181
1182         if (unlikely(!virtqueue_kick(vi->cvq)))
1183                 return vi->ctrl_status == VIRTIO_NET_OK;
1184
1185         /* Spin for a response, the kick causes an ioport write, trapping
1186          * into the hypervisor, so the request should be handled immediately.
1187          */
1188         while (!virtqueue_get_buf(vi->cvq, &tmp) &&
1189                !virtqueue_is_broken(vi->cvq))
1190                 cpu_relax();
1191
1192         return vi->ctrl_status == VIRTIO_NET_OK;
1193 }
1194
1195 static int virtnet_set_mac_address(struct net_device *dev, void *p)
1196 {
1197         struct virtnet_info *vi = netdev_priv(dev);
1198         struct virtio_device *vdev = vi->vdev;
1199         int ret;
1200         struct sockaddr *addr;
1201         struct scatterlist sg;
1202
1203         addr = kmalloc(sizeof(*addr), GFP_KERNEL);
1204         if (!addr)
1205                 return -ENOMEM;
1206         memcpy(addr, p, sizeof(*addr));
1207
1208         ret = eth_prepare_mac_addr_change(dev, addr);
1209         if (ret)
1210                 goto out;
1211
1212         if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
1213                 sg_init_one(&sg, addr->sa_data, dev->addr_len);
1214                 if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1215                                           VIRTIO_NET_CTRL_MAC_ADDR_SET, &sg)) {
1216                         dev_warn(&vdev->dev,
1217                                  "Failed to set mac address by vq command.\n");
1218                         ret = -EINVAL;
1219                         goto out;
1220                 }
1221         } else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC) &&
1222                    !virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1223                 unsigned int i;
1224
1225                 /* Naturally, this has an atomicity problem. */
1226                 for (i = 0; i < dev->addr_len; i++)
1227                         virtio_cwrite8(vdev,
1228                                        offsetof(struct virtio_net_config, mac) +
1229                                        i, addr->sa_data[i]);
1230         }
1231
1232         eth_commit_mac_addr_change(dev, p);
1233         ret = 0;
1234
1235 out:
1236         kfree(addr);
1237         return ret;
1238 }
1239
1240 static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
1241                                                struct rtnl_link_stats64 *tot)
1242 {
1243         struct virtnet_info *vi = netdev_priv(dev);
1244         int cpu;
1245         unsigned int start;
1246
1247         for_each_possible_cpu(cpu) {
1248                 struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
1249                 u64 tpackets, tbytes, rpackets, rbytes;
1250
1251                 do {
1252                         start = u64_stats_fetch_begin_irq(&stats->tx_syncp);
1253                         tpackets = stats->tx_packets;
1254                         tbytes   = stats->tx_bytes;
1255                 } while (u64_stats_fetch_retry_irq(&stats->tx_syncp, start));
1256
1257                 do {
1258                         start = u64_stats_fetch_begin_irq(&stats->rx_syncp);
1259                         rpackets = stats->rx_packets;
1260                         rbytes   = stats->rx_bytes;
1261                 } while (u64_stats_fetch_retry_irq(&stats->rx_syncp, start));
1262
1263                 tot->rx_packets += rpackets;
1264                 tot->tx_packets += tpackets;
1265                 tot->rx_bytes   += rbytes;
1266                 tot->tx_bytes   += tbytes;
1267         }
1268
1269         tot->tx_dropped = dev->stats.tx_dropped;
1270         tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
1271         tot->rx_dropped = dev->stats.rx_dropped;
1272         tot->rx_length_errors = dev->stats.rx_length_errors;
1273         tot->rx_frame_errors = dev->stats.rx_frame_errors;
1274
1275         return tot;
1276 }
1277
1278 #ifdef CONFIG_NET_POLL_CONTROLLER
1279 static void virtnet_netpoll(struct net_device *dev)
1280 {
1281         struct virtnet_info *vi = netdev_priv(dev);
1282         int i;
1283
1284         for (i = 0; i < vi->curr_queue_pairs; i++)
1285                 napi_schedule(&vi->rq[i].napi);
1286 }
1287 #endif
1288
1289 static void virtnet_ack_link_announce(struct virtnet_info *vi)
1290 {
1291         rtnl_lock();
1292         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
1293                                   VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL))
1294                 dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
1295         rtnl_unlock();
1296 }
1297
1298 static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
1299 {
1300         struct scatterlist sg;
1301         struct net_device *dev = vi->dev;
1302
1303         if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
1304                 return 0;
1305
1306         vi->ctrl_mq.virtqueue_pairs = cpu_to_virtio16(vi->vdev, queue_pairs);
1307         sg_init_one(&sg, &vi->ctrl_mq, sizeof(vi->ctrl_mq));
1308
1309         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
1310                                   VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg)) {
1311                 dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
1312                          queue_pairs);
1313                 return -EINVAL;
1314         } else {
1315                 vi->curr_queue_pairs = queue_pairs;
1316                 /* virtnet_open() will refill when device is going to up. */
1317                 if (dev->flags & IFF_UP)
1318                         schedule_delayed_work(&vi->refill, 0);
1319         }
1320
1321         return 0;
1322 }
1323
1324 static int virtnet_close(struct net_device *dev)
1325 {
1326         struct virtnet_info *vi = netdev_priv(dev);
1327         int i;
1328
1329         /* Make sure refill_work doesn't re-enable napi! */
1330         cancel_delayed_work_sync(&vi->refill);
1331
1332         for (i = 0; i < vi->max_queue_pairs; i++)
1333                 napi_disable(&vi->rq[i].napi);
1334
1335         return 0;
1336 }
1337
1338 static void virtnet_set_rx_mode(struct net_device *dev)
1339 {
1340         struct virtnet_info *vi = netdev_priv(dev);
1341         struct scatterlist sg[2];
1342         struct virtio_net_ctrl_mac *mac_data;
1343         struct netdev_hw_addr *ha;
1344         int uc_count;
1345         int mc_count;
1346         void *buf;
1347         int i;
1348
1349         /* We can't dynamically set ndo_set_rx_mode, so return gracefully */
1350         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
1351                 return;
1352
1353         vi->ctrl_promisc = ((dev->flags & IFF_PROMISC) != 0);
1354         vi->ctrl_allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
1355
1356         sg_init_one(sg, &vi->ctrl_promisc, sizeof(vi->ctrl_promisc));
1357
1358         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1359                                   VIRTIO_NET_CTRL_RX_PROMISC, sg))
1360                 dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
1361                          vi->ctrl_promisc ? "en" : "dis");
1362
1363         sg_init_one(sg, &vi->ctrl_allmulti, sizeof(vi->ctrl_allmulti));
1364
1365         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1366                                   VIRTIO_NET_CTRL_RX_ALLMULTI, sg))
1367                 dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
1368                          vi->ctrl_allmulti ? "en" : "dis");
1369
1370         uc_count = netdev_uc_count(dev);
1371         mc_count = netdev_mc_count(dev);
1372         /* MAC filter - use one buffer for both lists */
1373         buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
1374                       (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
1375         mac_data = buf;
1376         if (!buf)
1377                 return;
1378
1379         sg_init_table(sg, 2);
1380
1381         /* Store the unicast list and count in the front of the buffer */
1382         mac_data->entries = cpu_to_virtio32(vi->vdev, uc_count);
1383         i = 0;
1384         netdev_for_each_uc_addr(ha, dev)
1385                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1386
1387         sg_set_buf(&sg[0], mac_data,
1388                    sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
1389
1390         /* multicast list and count fill the end */
1391         mac_data = (void *)&mac_data->macs[uc_count][0];
1392
1393         mac_data->entries = cpu_to_virtio32(vi->vdev, mc_count);
1394         i = 0;
1395         netdev_for_each_mc_addr(ha, dev)
1396                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1397
1398         sg_set_buf(&sg[1], mac_data,
1399                    sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
1400
1401         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1402                                   VIRTIO_NET_CTRL_MAC_TABLE_SET, sg))
1403                 dev_warn(&dev->dev, "Failed to set MAC filter table.\n");
1404
1405         kfree(buf);
1406 }
1407
1408 static int virtnet_vlan_rx_add_vid(struct net_device *dev,
1409                                    __be16 proto, u16 vid)
1410 {
1411         struct virtnet_info *vi = netdev_priv(dev);
1412         struct scatterlist sg;
1413
1414         vi->ctrl_vid = vid;
1415         sg_init_one(&sg, &vi->ctrl_vid, sizeof(vi->ctrl_vid));
1416
1417         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1418                                   VIRTIO_NET_CTRL_VLAN_ADD, &sg))
1419                 dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
1420         return 0;
1421 }
1422
1423 static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
1424                                     __be16 proto, u16 vid)
1425 {
1426         struct virtnet_info *vi = netdev_priv(dev);
1427         struct scatterlist sg;
1428
1429         vi->ctrl_vid = vid;
1430         sg_init_one(&sg, &vi->ctrl_vid, sizeof(vi->ctrl_vid));
1431
1432         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1433                                   VIRTIO_NET_CTRL_VLAN_DEL, &sg))
1434                 dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
1435         return 0;
1436 }
1437
1438 static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
1439 {
1440         int i;
1441
1442         if (vi->affinity_hint_set) {
1443                 for (i = 0; i < vi->max_queue_pairs; i++) {
1444                         virtqueue_set_affinity(vi->rq[i].vq, -1);
1445                         virtqueue_set_affinity(vi->sq[i].vq, -1);
1446                 }
1447
1448                 vi->affinity_hint_set = false;
1449         }
1450 }
1451
1452 static void virtnet_set_affinity(struct virtnet_info *vi)
1453 {
1454         int i;
1455         int cpu;
1456
1457         /* In multiqueue mode, when the number of cpu is equal to the number of
1458          * queue pairs, we let the queue pairs to be private to one cpu by
1459          * setting the affinity hint to eliminate the contention.
1460          */
1461         if (vi->curr_queue_pairs == 1 ||
1462             vi->max_queue_pairs != num_online_cpus()) {
1463                 virtnet_clean_affinity(vi, -1);
1464                 return;
1465         }
1466
1467         i = 0;
1468         for_each_online_cpu(cpu) {
1469                 virtqueue_set_affinity(vi->rq[i].vq, cpu);
1470                 virtqueue_set_affinity(vi->sq[i].vq, cpu);
1471                 netif_set_xps_queue(vi->dev, cpumask_of(cpu), i);
1472                 i++;
1473         }
1474
1475         vi->affinity_hint_set = true;
1476 }
1477
1478 static int virtnet_cpu_online(unsigned int cpu, struct hlist_node *node)
1479 {
1480         struct virtnet_info *vi = hlist_entry_safe(node, struct virtnet_info,
1481                                                    node);
1482         virtnet_set_affinity(vi);
1483         return 0;
1484 }
1485
1486 static int virtnet_cpu_dead(unsigned int cpu, struct hlist_node *node)
1487 {
1488         struct virtnet_info *vi = hlist_entry_safe(node, struct virtnet_info,
1489                                                    node_dead);
1490         virtnet_set_affinity(vi);
1491         return 0;
1492 }
1493
1494 static int virtnet_cpu_down_prep(unsigned int cpu, struct hlist_node *node)
1495 {
1496         struct virtnet_info *vi = hlist_entry_safe(node, struct virtnet_info,
1497                                                    node);
1498
1499         virtnet_clean_affinity(vi, cpu);
1500         return 0;
1501 }
1502
1503 static enum cpuhp_state virtionet_online;
1504
1505 static int virtnet_cpu_notif_add(struct virtnet_info *vi)
1506 {
1507         int ret;
1508
1509         ret = cpuhp_state_add_instance_nocalls(virtionet_online, &vi->node);
1510         if (ret)
1511                 return ret;
1512         ret = cpuhp_state_add_instance_nocalls(CPUHP_VIRT_NET_DEAD,
1513                                                &vi->node_dead);
1514         if (!ret)
1515                 return ret;
1516         cpuhp_state_remove_instance_nocalls(virtionet_online, &vi->node);
1517         return ret;
1518 }
1519
1520 static void virtnet_cpu_notif_remove(struct virtnet_info *vi)
1521 {
1522         cpuhp_state_remove_instance_nocalls(virtionet_online, &vi->node);
1523         cpuhp_state_remove_instance_nocalls(CPUHP_VIRT_NET_DEAD,
1524                                             &vi->node_dead);
1525 }
1526
1527 static void virtnet_get_ringparam(struct net_device *dev,
1528                                 struct ethtool_ringparam *ring)
1529 {
1530         struct virtnet_info *vi = netdev_priv(dev);
1531
1532         ring->rx_max_pending = virtqueue_get_vring_size(vi->rq[0].vq);
1533         ring->tx_max_pending = virtqueue_get_vring_size(vi->sq[0].vq);
1534         ring->rx_pending = ring->rx_max_pending;
1535         ring->tx_pending = ring->tx_max_pending;
1536 }
1537
1538
1539 static void virtnet_get_drvinfo(struct net_device *dev,
1540                                 struct ethtool_drvinfo *info)
1541 {
1542         struct virtnet_info *vi = netdev_priv(dev);
1543         struct virtio_device *vdev = vi->vdev;
1544
1545         strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
1546         strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
1547         strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
1548
1549 }
1550
1551 /* TODO: Eliminate OOO packets during switching */
1552 static int virtnet_set_channels(struct net_device *dev,
1553                                 struct ethtool_channels *channels)
1554 {
1555         struct virtnet_info *vi = netdev_priv(dev);
1556         u16 queue_pairs = channels->combined_count;
1557         int err;
1558
1559         /* We don't support separate rx/tx channels.
1560          * We don't allow setting 'other' channels.
1561          */
1562         if (channels->rx_count || channels->tx_count || channels->other_count)
1563                 return -EINVAL;
1564
1565         if (queue_pairs > vi->max_queue_pairs || queue_pairs == 0)
1566                 return -EINVAL;
1567
1568         /* For now we don't support modifying channels while XDP is loaded
1569          * also when XDP is loaded all RX queues have XDP programs so we only
1570          * need to check a single RX queue.
1571          */
1572         if (vi->rq[0].xdp_prog)
1573                 return -EINVAL;
1574
1575         get_online_cpus();
1576         err = virtnet_set_queues(vi, queue_pairs);
1577         if (!err) {
1578                 netif_set_real_num_tx_queues(dev, queue_pairs);
1579                 netif_set_real_num_rx_queues(dev, queue_pairs);
1580
1581                 virtnet_set_affinity(vi);
1582         }
1583         put_online_cpus();
1584
1585         return err;
1586 }
1587
1588 static void virtnet_get_channels(struct net_device *dev,
1589                                  struct ethtool_channels *channels)
1590 {
1591         struct virtnet_info *vi = netdev_priv(dev);
1592
1593         channels->combined_count = vi->curr_queue_pairs;
1594         channels->max_combined = vi->max_queue_pairs;
1595         channels->max_other = 0;
1596         channels->rx_count = 0;
1597         channels->tx_count = 0;
1598         channels->other_count = 0;
1599 }
1600
1601 /* Check if the user is trying to change anything besides speed/duplex */
1602 static bool virtnet_validate_ethtool_cmd(const struct ethtool_cmd *cmd)
1603 {
1604         struct ethtool_cmd diff1 = *cmd;
1605         struct ethtool_cmd diff2 = {};
1606
1607         /* cmd is always set so we need to clear it, validate the port type
1608          * and also without autonegotiation we can ignore advertising
1609          */
1610         ethtool_cmd_speed_set(&diff1, 0);
1611         diff2.port = PORT_OTHER;
1612         diff1.advertising = 0;
1613         diff1.duplex = 0;
1614         diff1.cmd = 0;
1615
1616         return !memcmp(&diff1, &diff2, sizeof(diff1));
1617 }
1618
1619 static int virtnet_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1620 {
1621         struct virtnet_info *vi = netdev_priv(dev);
1622         u32 speed;
1623
1624         speed = ethtool_cmd_speed(cmd);
1625         /* don't allow custom speed and duplex */
1626         if (!ethtool_validate_speed(speed) ||
1627             !ethtool_validate_duplex(cmd->duplex) ||
1628             !virtnet_validate_ethtool_cmd(cmd))
1629                 return -EINVAL;
1630         vi->speed = speed;
1631         vi->duplex = cmd->duplex;
1632
1633         return 0;
1634 }
1635
1636 static int virtnet_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1637 {
1638         struct virtnet_info *vi = netdev_priv(dev);
1639
1640         ethtool_cmd_speed_set(cmd, vi->speed);
1641         cmd->duplex = vi->duplex;
1642         cmd->port = PORT_OTHER;
1643
1644         return 0;
1645 }
1646
1647 static void virtnet_init_settings(struct net_device *dev)
1648 {
1649         struct virtnet_info *vi = netdev_priv(dev);
1650
1651         vi->speed = SPEED_UNKNOWN;
1652         vi->duplex = DUPLEX_UNKNOWN;
1653 }
1654
1655 static const struct ethtool_ops virtnet_ethtool_ops = {
1656         .get_drvinfo = virtnet_get_drvinfo,
1657         .get_link = ethtool_op_get_link,
1658         .get_ringparam = virtnet_get_ringparam,
1659         .set_channels = virtnet_set_channels,
1660         .get_channels = virtnet_get_channels,
1661         .get_ts_info = ethtool_op_get_ts_info,
1662         .get_settings = virtnet_get_settings,
1663         .set_settings = virtnet_set_settings,
1664 };
1665
1666 static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog)
1667 {
1668         unsigned long int max_sz = PAGE_SIZE - sizeof(struct padded_vnet_hdr);
1669         struct virtnet_info *vi = netdev_priv(dev);
1670         struct bpf_prog *old_prog;
1671         u16 xdp_qp = 0, curr_qp;
1672         int i, err;
1673
1674         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1675             virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO6)) {
1676                 netdev_warn(dev, "can't set XDP while host is implementing LRO, disable LRO first\n");
1677                 return -EOPNOTSUPP;
1678         }
1679
1680         if (vi->mergeable_rx_bufs && !vi->any_header_sg) {
1681                 netdev_warn(dev, "XDP expects header/data in single page, any_header_sg required\n");
1682                 return -EINVAL;
1683         }
1684
1685         if (dev->mtu > max_sz) {
1686                 netdev_warn(dev, "XDP requires MTU less than %lu\n", max_sz);
1687                 return -EINVAL;
1688         }
1689
1690         curr_qp = vi->curr_queue_pairs - vi->xdp_queue_pairs;
1691         if (prog)
1692                 xdp_qp = nr_cpu_ids;
1693
1694         /* XDP requires extra queues for XDP_TX */
1695         if (curr_qp + xdp_qp > vi->max_queue_pairs) {
1696                 netdev_warn(dev, "request %i queues but max is %i\n",
1697                             curr_qp + xdp_qp, vi->max_queue_pairs);
1698                 return -ENOMEM;
1699         }
1700
1701         err = virtnet_set_queues(vi, curr_qp + xdp_qp);
1702         if (err) {
1703                 dev_warn(&dev->dev, "XDP Device queue allocation failure.\n");
1704                 return err;
1705         }
1706
1707         if (prog) {
1708                 prog = bpf_prog_add(prog, vi->max_queue_pairs - 1);
1709                 if (IS_ERR(prog)) {
1710                         virtnet_set_queues(vi, curr_qp);
1711                         return PTR_ERR(prog);
1712                 }
1713         }
1714
1715         vi->xdp_queue_pairs = xdp_qp;
1716         netif_set_real_num_rx_queues(dev, curr_qp + xdp_qp);
1717
1718         for (i = 0; i < vi->max_queue_pairs; i++) {
1719                 old_prog = rtnl_dereference(vi->rq[i].xdp_prog);
1720                 rcu_assign_pointer(vi->rq[i].xdp_prog, prog);
1721                 if (old_prog)
1722                         bpf_prog_put(old_prog);
1723         }
1724
1725         return 0;
1726 }
1727
1728 static bool virtnet_xdp_query(struct net_device *dev)
1729 {
1730         struct virtnet_info *vi = netdev_priv(dev);
1731         int i;
1732
1733         for (i = 0; i < vi->max_queue_pairs; i++) {
1734                 if (vi->rq[i].xdp_prog)
1735                         return true;
1736         }
1737         return false;
1738 }
1739
1740 static int virtnet_xdp(struct net_device *dev, struct netdev_xdp *xdp)
1741 {
1742         switch (xdp->command) {
1743         case XDP_SETUP_PROG:
1744                 return virtnet_xdp_set(dev, xdp->prog);
1745         case XDP_QUERY_PROG:
1746                 xdp->prog_attached = virtnet_xdp_query(dev);
1747                 return 0;
1748         default:
1749                 return -EINVAL;
1750         }
1751 }
1752
1753 static const struct net_device_ops virtnet_netdev = {
1754         .ndo_open            = virtnet_open,
1755         .ndo_stop            = virtnet_close,
1756         .ndo_start_xmit      = start_xmit,
1757         .ndo_validate_addr   = eth_validate_addr,
1758         .ndo_set_mac_address = virtnet_set_mac_address,
1759         .ndo_set_rx_mode     = virtnet_set_rx_mode,
1760         .ndo_get_stats64     = virtnet_stats,
1761         .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
1762         .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
1763 #ifdef CONFIG_NET_POLL_CONTROLLER
1764         .ndo_poll_controller = virtnet_netpoll,
1765 #endif
1766 #ifdef CONFIG_NET_RX_BUSY_POLL
1767         .ndo_busy_poll          = virtnet_busy_poll,
1768 #endif
1769         .ndo_xdp                = virtnet_xdp,
1770 };
1771
1772 static void virtnet_config_changed_work(struct work_struct *work)
1773 {
1774         struct virtnet_info *vi =
1775                 container_of(work, struct virtnet_info, config_work);
1776         u16 v;
1777
1778         if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS,
1779                                  struct virtio_net_config, status, &v) < 0)
1780                 return;
1781
1782         if (v & VIRTIO_NET_S_ANNOUNCE) {
1783                 netdev_notify_peers(vi->dev);
1784                 virtnet_ack_link_announce(vi);
1785         }
1786
1787         /* Ignore unknown (future) status bits */
1788         v &= VIRTIO_NET_S_LINK_UP;
1789
1790         if (vi->status == v)
1791                 return;
1792
1793         vi->status = v;
1794
1795         if (vi->status & VIRTIO_NET_S_LINK_UP) {
1796                 netif_carrier_on(vi->dev);
1797                 netif_tx_wake_all_queues(vi->dev);
1798         } else {
1799                 netif_carrier_off(vi->dev);
1800                 netif_tx_stop_all_queues(vi->dev);
1801         }
1802 }
1803
1804 static void virtnet_config_changed(struct virtio_device *vdev)
1805 {
1806         struct virtnet_info *vi = vdev->priv;
1807
1808         schedule_work(&vi->config_work);
1809 }
1810
1811 static void virtnet_free_queues(struct virtnet_info *vi)
1812 {
1813         int i;
1814
1815         for (i = 0; i < vi->max_queue_pairs; i++) {
1816                 napi_hash_del(&vi->rq[i].napi);
1817                 netif_napi_del(&vi->rq[i].napi);
1818         }
1819
1820         /* We called napi_hash_del() before netif_napi_del(),
1821          * we need to respect an RCU grace period before freeing vi->rq
1822          */
1823         synchronize_net();
1824
1825         kfree(vi->rq);
1826         kfree(vi->sq);
1827 }
1828
1829 static void free_receive_bufs(struct virtnet_info *vi)
1830 {
1831         struct bpf_prog *old_prog;
1832         int i;
1833
1834         rtnl_lock();
1835         for (i = 0; i < vi->max_queue_pairs; i++) {
1836                 while (vi->rq[i].pages)
1837                         __free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
1838
1839                 old_prog = rtnl_dereference(vi->rq[i].xdp_prog);
1840                 RCU_INIT_POINTER(vi->rq[i].xdp_prog, NULL);
1841                 if (old_prog)
1842                         bpf_prog_put(old_prog);
1843         }
1844         rtnl_unlock();
1845 }
1846
1847 static void free_receive_page_frags(struct virtnet_info *vi)
1848 {
1849         int i;
1850         for (i = 0; i < vi->max_queue_pairs; i++)
1851                 if (vi->rq[i].alloc_frag.page)
1852                         put_page(vi->rq[i].alloc_frag.page);
1853 }
1854
1855 static bool is_xdp_queue(struct virtnet_info *vi, int q)
1856 {
1857         if (q < (vi->curr_queue_pairs - vi->xdp_queue_pairs))
1858                 return false;
1859         else if (q < vi->curr_queue_pairs)
1860                 return true;
1861         else
1862                 return false;
1863 }
1864
1865 static void free_unused_bufs(struct virtnet_info *vi)
1866 {
1867         void *buf;
1868         int i;
1869
1870         for (i = 0; i < vi->max_queue_pairs; i++) {
1871                 struct virtqueue *vq = vi->sq[i].vq;
1872                 while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
1873                         if (!is_xdp_queue(vi, i))
1874                                 dev_kfree_skb(buf);
1875                         else
1876                                 put_page(virt_to_head_page(buf));
1877                 }
1878         }
1879
1880         for (i = 0; i < vi->max_queue_pairs; i++) {
1881                 struct virtqueue *vq = vi->rq[i].vq;
1882
1883                 while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
1884                         if (vi->mergeable_rx_bufs) {
1885                                 unsigned long ctx = (unsigned long)buf;
1886                                 void *base = mergeable_ctx_to_buf_address(ctx);
1887                                 put_page(virt_to_head_page(base));
1888                         } else if (vi->big_packets) {
1889                                 give_pages(&vi->rq[i], buf);
1890                         } else {
1891                                 dev_kfree_skb(buf);
1892                         }
1893                 }
1894         }
1895 }
1896
1897 static void virtnet_del_vqs(struct virtnet_info *vi)
1898 {
1899         struct virtio_device *vdev = vi->vdev;
1900
1901         virtnet_clean_affinity(vi, -1);
1902
1903         vdev->config->del_vqs(vdev);
1904
1905         virtnet_free_queues(vi);
1906 }
1907
1908 static int virtnet_find_vqs(struct virtnet_info *vi)
1909 {
1910         vq_callback_t **callbacks;
1911         struct virtqueue **vqs;
1912         int ret = -ENOMEM;
1913         int i, total_vqs;
1914         const char **names;
1915
1916         /* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
1917          * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
1918          * possible control vq.
1919          */
1920         total_vqs = vi->max_queue_pairs * 2 +
1921                     virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
1922
1923         /* Allocate space for find_vqs parameters */
1924         vqs = kzalloc(total_vqs * sizeof(*vqs), GFP_KERNEL);
1925         if (!vqs)
1926                 goto err_vq;
1927         callbacks = kmalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL);
1928         if (!callbacks)
1929                 goto err_callback;
1930         names = kmalloc(total_vqs * sizeof(*names), GFP_KERNEL);
1931         if (!names)
1932                 goto err_names;
1933
1934         /* Parameters for control virtqueue, if any */
1935         if (vi->has_cvq) {
1936                 callbacks[total_vqs - 1] = NULL;
1937                 names[total_vqs - 1] = "control";
1938         }
1939
1940         /* Allocate/initialize parameters for send/receive virtqueues */
1941         for (i = 0; i < vi->max_queue_pairs; i++) {
1942                 callbacks[rxq2vq(i)] = skb_recv_done;
1943                 callbacks[txq2vq(i)] = skb_xmit_done;
1944                 sprintf(vi->rq[i].name, "input.%d", i);
1945                 sprintf(vi->sq[i].name, "output.%d", i);
1946                 names[rxq2vq(i)] = vi->rq[i].name;
1947                 names[txq2vq(i)] = vi->sq[i].name;
1948         }
1949
1950         ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
1951                                          names);
1952         if (ret)
1953                 goto err_find;
1954
1955         if (vi->has_cvq) {
1956                 vi->cvq = vqs[total_vqs - 1];
1957                 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1958                         vi->dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
1959         }
1960
1961         for (i = 0; i < vi->max_queue_pairs; i++) {
1962                 vi->rq[i].vq = vqs[rxq2vq(i)];
1963                 vi->sq[i].vq = vqs[txq2vq(i)];
1964         }
1965
1966         kfree(names);
1967         kfree(callbacks);
1968         kfree(vqs);
1969
1970         return 0;
1971
1972 err_find:
1973         kfree(names);
1974 err_names:
1975         kfree(callbacks);
1976 err_callback:
1977         kfree(vqs);
1978 err_vq:
1979         return ret;
1980 }
1981
1982 static int virtnet_alloc_queues(struct virtnet_info *vi)
1983 {
1984         int i;
1985
1986         vi->sq = kzalloc(sizeof(*vi->sq) * vi->max_queue_pairs, GFP_KERNEL);
1987         if (!vi->sq)
1988                 goto err_sq;
1989         vi->rq = kzalloc(sizeof(*vi->rq) * vi->max_queue_pairs, GFP_KERNEL);
1990         if (!vi->rq)
1991                 goto err_rq;
1992
1993         INIT_DELAYED_WORK(&vi->refill, refill_work);
1994         for (i = 0; i < vi->max_queue_pairs; i++) {
1995                 vi->rq[i].pages = NULL;
1996                 netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
1997                                napi_weight);
1998
1999                 sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
2000                 ewma_pkt_len_init(&vi->rq[i].mrg_avg_pkt_len);
2001                 sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
2002         }
2003
2004         return 0;
2005
2006 err_rq:
2007         kfree(vi->sq);
2008 err_sq:
2009         return -ENOMEM;
2010 }
2011
2012 static int init_vqs(struct virtnet_info *vi)
2013 {
2014         int ret;
2015
2016         /* Allocate send & receive queues */
2017         ret = virtnet_alloc_queues(vi);
2018         if (ret)
2019                 goto err;
2020
2021         ret = virtnet_find_vqs(vi);
2022         if (ret)
2023                 goto err_free;
2024
2025         get_online_cpus();
2026         virtnet_set_affinity(vi);
2027         put_online_cpus();
2028
2029         return 0;
2030
2031 err_free:
2032         virtnet_free_queues(vi);
2033 err:
2034         return ret;
2035 }
2036
2037 #ifdef CONFIG_SYSFS
2038 static ssize_t mergeable_rx_buffer_size_show(struct netdev_rx_queue *queue,
2039                 struct rx_queue_attribute *attribute, char *buf)
2040 {
2041         struct virtnet_info *vi = netdev_priv(queue->dev);
2042         unsigned int queue_index = get_netdev_rx_queue_index(queue);
2043         struct ewma_pkt_len *avg;
2044
2045         BUG_ON(queue_index >= vi->max_queue_pairs);
2046         avg = &vi->rq[queue_index].mrg_avg_pkt_len;
2047         return sprintf(buf, "%u\n", get_mergeable_buf_len(avg));
2048 }
2049
2050 static struct rx_queue_attribute mergeable_rx_buffer_size_attribute =
2051         __ATTR_RO(mergeable_rx_buffer_size);
2052
2053 static struct attribute *virtio_net_mrg_rx_attrs[] = {
2054         &mergeable_rx_buffer_size_attribute.attr,
2055         NULL
2056 };
2057
2058 static const struct attribute_group virtio_net_mrg_rx_group = {
2059         .name = "virtio_net",
2060         .attrs = virtio_net_mrg_rx_attrs
2061 };
2062 #endif
2063
2064 static bool virtnet_fail_on_feature(struct virtio_device *vdev,
2065                                     unsigned int fbit,
2066                                     const char *fname, const char *dname)
2067 {
2068         if (!virtio_has_feature(vdev, fbit))
2069                 return false;
2070
2071         dev_err(&vdev->dev, "device advertises feature %s but not %s",
2072                 fname, dname);
2073
2074         return true;
2075 }
2076
2077 #define VIRTNET_FAIL_ON(vdev, fbit, dbit)                       \
2078         virtnet_fail_on_feature(vdev, fbit, #fbit, dbit)
2079
2080 static bool virtnet_validate_features(struct virtio_device *vdev)
2081 {
2082         if (!virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ) &&
2083             (VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_RX,
2084                              "VIRTIO_NET_F_CTRL_VQ") ||
2085              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_VLAN,
2086                              "VIRTIO_NET_F_CTRL_VQ") ||
2087              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE,
2088                              "VIRTIO_NET_F_CTRL_VQ") ||
2089              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_MQ, "VIRTIO_NET_F_CTRL_VQ") ||
2090              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR,
2091                              "VIRTIO_NET_F_CTRL_VQ"))) {
2092                 return false;
2093         }
2094
2095         return true;
2096 }
2097
2098 #define MIN_MTU ETH_MIN_MTU
2099 #define MAX_MTU ETH_MAX_MTU
2100
2101 static int virtnet_probe(struct virtio_device *vdev)
2102 {
2103         int i, err;
2104         struct net_device *dev;
2105         struct virtnet_info *vi;
2106         u16 max_queue_pairs;
2107         int mtu;
2108
2109         if (!vdev->config->get) {
2110                 dev_err(&vdev->dev, "%s failure: config access disabled\n",
2111                         __func__);
2112                 return -EINVAL;
2113         }
2114
2115         if (!virtnet_validate_features(vdev))
2116                 return -EINVAL;
2117
2118         /* Find if host supports multiqueue virtio_net device */
2119         err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ,
2120                                    struct virtio_net_config,
2121                                    max_virtqueue_pairs, &max_queue_pairs);
2122
2123         /* We need at least 2 queue's */
2124         if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
2125             max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
2126             !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
2127                 max_queue_pairs = 1;
2128
2129         /* Allocate ourselves a network device with room for our info */
2130         dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
2131         if (!dev)
2132                 return -ENOMEM;
2133
2134         /* Set up network device as normal. */
2135         dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE;
2136         dev->netdev_ops = &virtnet_netdev;
2137         dev->features = NETIF_F_HIGHDMA;
2138
2139         dev->ethtool_ops = &virtnet_ethtool_ops;
2140         SET_NETDEV_DEV(dev, &vdev->dev);
2141
2142         /* Do we support "hardware" checksums? */
2143         if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
2144                 /* This opens up the world of extra features. */
2145                 dev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_SG;
2146                 if (csum)
2147                         dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG;
2148
2149                 if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
2150                         dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
2151                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
2152                 }
2153                 /* Individual feature bits: what can host handle? */
2154                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
2155                         dev->hw_features |= NETIF_F_TSO;
2156                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
2157                         dev->hw_features |= NETIF_F_TSO6;
2158                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
2159                         dev->hw_features |= NETIF_F_TSO_ECN;
2160                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
2161                         dev->hw_features |= NETIF_F_UFO;
2162
2163                 dev->features |= NETIF_F_GSO_ROBUST;
2164
2165                 if (gso)
2166                         dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
2167                 /* (!csum && gso) case will be fixed by register_netdev() */
2168         }
2169         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_CSUM))
2170                 dev->features |= NETIF_F_RXCSUM;
2171
2172         dev->vlan_features = dev->features;
2173
2174         /* MTU range: 68 - 65535 */
2175         dev->min_mtu = MIN_MTU;
2176         dev->max_mtu = MAX_MTU;
2177
2178         /* Configuration may specify what MAC to use.  Otherwise random. */
2179         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
2180                 virtio_cread_bytes(vdev,
2181                                    offsetof(struct virtio_net_config, mac),
2182                                    dev->dev_addr, dev->addr_len);
2183         else
2184                 eth_hw_addr_random(dev);
2185
2186         /* Set up our device-specific information */
2187         vi = netdev_priv(dev);
2188         vi->dev = dev;
2189         vi->vdev = vdev;
2190         vdev->priv = vi;
2191         vi->stats = alloc_percpu(struct virtnet_stats);
2192         err = -ENOMEM;
2193         if (vi->stats == NULL)
2194                 goto free;
2195
2196         for_each_possible_cpu(i) {
2197                 struct virtnet_stats *virtnet_stats;
2198                 virtnet_stats = per_cpu_ptr(vi->stats, i);
2199                 u64_stats_init(&virtnet_stats->tx_syncp);
2200                 u64_stats_init(&virtnet_stats->rx_syncp);
2201         }
2202
2203         INIT_WORK(&vi->config_work, virtnet_config_changed_work);
2204
2205         /* If we can receive ANY GSO packets, we must allocate large ones. */
2206         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
2207             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
2208             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN) ||
2209             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UFO))
2210                 vi->big_packets = true;
2211
2212         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
2213                 vi->mergeable_rx_bufs = true;
2214
2215         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF) ||
2216             virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
2217                 vi->hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
2218         else
2219                 vi->hdr_len = sizeof(struct virtio_net_hdr);
2220
2221         if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT) ||
2222             virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
2223                 vi->any_header_sg = true;
2224
2225         if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
2226                 vi->has_cvq = true;
2227
2228         if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) {
2229                 mtu = virtio_cread16(vdev,
2230                                      offsetof(struct virtio_net_config,
2231                                               mtu));
2232                 if (mtu < dev->min_mtu) {
2233                         __virtio_clear_bit(vdev, VIRTIO_NET_F_MTU);
2234                 } else {
2235                         dev->mtu = mtu;
2236                         dev->max_mtu = mtu;
2237                 }
2238         }
2239
2240         if (vi->any_header_sg)
2241                 dev->needed_headroom = vi->hdr_len;
2242
2243         /* Enable multiqueue by default */
2244         if (num_online_cpus() >= max_queue_pairs)
2245                 vi->curr_queue_pairs = max_queue_pairs;
2246         else
2247                 vi->curr_queue_pairs = num_online_cpus();
2248         vi->max_queue_pairs = max_queue_pairs;
2249
2250         /* Allocate/initialize the rx/tx queues, and invoke find_vqs */
2251         err = init_vqs(vi);
2252         if (err)
2253                 goto free_stats;
2254
2255 #ifdef CONFIG_SYSFS
2256         if (vi->mergeable_rx_bufs)
2257                 dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
2258 #endif
2259         netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
2260         netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
2261
2262         virtnet_init_settings(dev);
2263
2264         err = register_netdev(dev);
2265         if (err) {
2266                 pr_debug("virtio_net: registering device failed\n");
2267                 goto free_vqs;
2268         }
2269
2270         virtio_device_ready(vdev);
2271
2272         err = virtnet_cpu_notif_add(vi);
2273         if (err) {
2274                 pr_debug("virtio_net: registering cpu notifier failed\n");
2275                 goto free_unregister_netdev;
2276         }
2277
2278         rtnl_lock();
2279         virtnet_set_queues(vi, vi->curr_queue_pairs);
2280         rtnl_unlock();
2281
2282         /* Assume link up if device can't report link status,
2283            otherwise get link status from config. */
2284         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
2285                 netif_carrier_off(dev);
2286                 schedule_work(&vi->config_work);
2287         } else {
2288                 vi->status = VIRTIO_NET_S_LINK_UP;
2289                 netif_carrier_on(dev);
2290         }
2291
2292         pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
2293                  dev->name, max_queue_pairs);
2294
2295         return 0;
2296
2297 free_unregister_netdev:
2298         vi->vdev->config->reset(vdev);
2299
2300         unregister_netdev(dev);
2301 free_vqs:
2302         cancel_delayed_work_sync(&vi->refill);
2303         free_receive_page_frags(vi);
2304         virtnet_del_vqs(vi);
2305 free_stats:
2306         free_percpu(vi->stats);
2307 free:
2308         free_netdev(dev);
2309         return err;
2310 }
2311
2312 static void remove_vq_common(struct virtnet_info *vi)
2313 {
2314         vi->vdev->config->reset(vi->vdev);
2315
2316         /* Free unused buffers in both send and recv, if any. */
2317         free_unused_bufs(vi);
2318
2319         free_receive_bufs(vi);
2320
2321         free_receive_page_frags(vi);
2322
2323         virtnet_del_vqs(vi);
2324 }
2325
2326 static void virtnet_remove(struct virtio_device *vdev)
2327 {
2328         struct virtnet_info *vi = vdev->priv;
2329
2330         virtnet_cpu_notif_remove(vi);
2331
2332         /* Make sure no work handler is accessing the device. */
2333         flush_work(&vi->config_work);
2334
2335         unregister_netdev(vi->dev);
2336
2337         remove_vq_common(vi);
2338
2339         free_percpu(vi->stats);
2340         free_netdev(vi->dev);
2341 }
2342
2343 #ifdef CONFIG_PM_SLEEP
2344 static int virtnet_freeze(struct virtio_device *vdev)
2345 {
2346         struct virtnet_info *vi = vdev->priv;
2347         int i;
2348
2349         virtnet_cpu_notif_remove(vi);
2350
2351         /* Make sure no work handler is accessing the device */
2352         flush_work(&vi->config_work);
2353
2354         netif_device_detach(vi->dev);
2355         cancel_delayed_work_sync(&vi->refill);
2356
2357         if (netif_running(vi->dev)) {
2358                 for (i = 0; i < vi->max_queue_pairs; i++)
2359                         napi_disable(&vi->rq[i].napi);
2360         }
2361
2362         remove_vq_common(vi);
2363
2364         return 0;
2365 }
2366
2367 static int virtnet_restore(struct virtio_device *vdev)
2368 {
2369         struct virtnet_info *vi = vdev->priv;
2370         int err, i;
2371
2372         err = init_vqs(vi);
2373         if (err)
2374                 return err;
2375
2376         virtio_device_ready(vdev);
2377
2378         if (netif_running(vi->dev)) {
2379                 for (i = 0; i < vi->curr_queue_pairs; i++)
2380                         if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
2381                                 schedule_delayed_work(&vi->refill, 0);
2382
2383                 for (i = 0; i < vi->max_queue_pairs; i++)
2384                         virtnet_napi_enable(&vi->rq[i]);
2385         }
2386
2387         netif_device_attach(vi->dev);
2388
2389         rtnl_lock();
2390         virtnet_set_queues(vi, vi->curr_queue_pairs);
2391         rtnl_unlock();
2392
2393         err = virtnet_cpu_notif_add(vi);
2394         if (err)
2395                 return err;
2396
2397         return 0;
2398 }
2399 #endif
2400
2401 static struct virtio_device_id id_table[] = {
2402         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
2403         { 0 },
2404 };
2405
2406 #define VIRTNET_FEATURES \
2407         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM, \
2408         VIRTIO_NET_F_MAC, \
2409         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6, \
2410         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6, \
2411         VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO, \
2412         VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ, \
2413         VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN, \
2414         VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, \
2415         VIRTIO_NET_F_CTRL_MAC_ADDR, \
2416         VIRTIO_NET_F_MTU
2417
2418 static unsigned int features[] = {
2419         VIRTNET_FEATURES,
2420 };
2421
2422 static unsigned int features_legacy[] = {
2423         VIRTNET_FEATURES,
2424         VIRTIO_NET_F_GSO,
2425         VIRTIO_F_ANY_LAYOUT,
2426 };
2427
2428 static struct virtio_driver virtio_net_driver = {
2429         .feature_table = features,
2430         .feature_table_size = ARRAY_SIZE(features),
2431         .feature_table_legacy = features_legacy,
2432         .feature_table_size_legacy = ARRAY_SIZE(features_legacy),
2433         .driver.name =  KBUILD_MODNAME,
2434         .driver.owner = THIS_MODULE,
2435         .id_table =     id_table,
2436         .probe =        virtnet_probe,
2437         .remove =       virtnet_remove,
2438         .config_changed = virtnet_config_changed,
2439 #ifdef CONFIG_PM_SLEEP
2440         .freeze =       virtnet_freeze,
2441         .restore =      virtnet_restore,
2442 #endif
2443 };
2444
2445 static __init int virtio_net_driver_init(void)
2446 {
2447         int ret;
2448
2449         ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "AP_VIRT_NET_ONLINE",
2450                                       virtnet_cpu_online,
2451                                       virtnet_cpu_down_prep);
2452         if (ret < 0)
2453                 goto out;
2454         virtionet_online = ret;
2455         ret = cpuhp_setup_state_multi(CPUHP_VIRT_NET_DEAD, "VIRT_NET_DEAD",
2456                                       NULL, virtnet_cpu_dead);
2457         if (ret)
2458                 goto err_dead;
2459
2460         ret = register_virtio_driver(&virtio_net_driver);
2461         if (ret)
2462                 goto err_virtio;
2463         return 0;
2464 err_virtio:
2465         cpuhp_remove_multi_state(CPUHP_VIRT_NET_DEAD);
2466 err_dead:
2467         cpuhp_remove_multi_state(virtionet_online);
2468 out:
2469         return ret;
2470 }
2471 module_init(virtio_net_driver_init);
2472
2473 static __exit void virtio_net_driver_exit(void)
2474 {
2475         cpuhp_remove_multi_state(CPUHP_VIRT_NET_DEAD);
2476         cpuhp_remove_multi_state(virtionet_online);
2477         unregister_virtio_driver(&virtio_net_driver);
2478 }
2479 module_exit(virtio_net_driver_exit);
2480
2481 MODULE_DEVICE_TABLE(virtio, id_table);
2482 MODULE_DESCRIPTION("Virtio network driver");
2483 MODULE_LICENSE("GPL");