linux/drivers/net/virtio_net.c
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   1/* A network driver using virtio.
   2 *
   3 * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License as published by
   7 * the Free Software Foundation; either version 2 of the License, or
   8 * (at your option) any later version.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program; if not, write to the Free Software
  17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18 */
  19//#define DEBUG
  20#include <linux/netdevice.h>
  21#include <linux/etherdevice.h>
  22#include <linux/ethtool.h>
  23#include <linux/module.h>
  24#include <linux/virtio.h>
  25#include <linux/virtio_net.h>
  26#include <linux/scatterlist.h>
  27#include <linux/if_vlan.h>
  28#include <linux/slab.h>
  29#include <linux/cpu.h>
  30
  31static int napi_weight = NAPI_POLL_WEIGHT;
  32module_param(napi_weight, int, 0444);
  33
  34static bool csum = true, gso = true;
  35module_param(csum, bool, 0444);
  36module_param(gso, bool, 0444);
  37
  38/* FIXME: MTU in config. */
  39#define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
  40#define GOOD_COPY_LEN   128
  41
  42#define VIRTNET_DRIVER_VERSION "1.0.0"
  43
  44struct virtnet_stats {
  45        struct u64_stats_sync tx_syncp;
  46        struct u64_stats_sync rx_syncp;
  47        u64 tx_bytes;
  48        u64 tx_packets;
  49
  50        u64 rx_bytes;
  51        u64 rx_packets;
  52};
  53
  54/* Internal representation of a send virtqueue */
  55struct send_queue {
  56        /* Virtqueue associated with this send _queue */
  57        struct virtqueue *vq;
  58
  59        /* TX: fragments + linear part + virtio header */
  60        struct scatterlist sg[MAX_SKB_FRAGS + 2];
  61
  62        /* Name of the send queue: output.$index */
  63        char name[40];
  64};
  65
  66/* Internal representation of a receive virtqueue */
  67struct receive_queue {
  68        /* Virtqueue associated with this receive_queue */
  69        struct virtqueue *vq;
  70
  71        struct napi_struct napi;
  72
  73        /* Number of input buffers, and max we've ever had. */
  74        unsigned int num, max;
  75
  76        /* Chain pages by the private ptr. */
  77        struct page *pages;
  78
  79        /* RX: fragments + linear part + virtio header */
  80        struct scatterlist sg[MAX_SKB_FRAGS + 2];
  81
  82        /* Name of this receive queue: input.$index */
  83        char name[40];
  84};
  85
  86struct virtnet_info {
  87        struct virtio_device *vdev;
  88        struct virtqueue *cvq;
  89        struct net_device *dev;
  90        struct send_queue *sq;
  91        struct receive_queue *rq;
  92        unsigned int status;
  93
  94        /* Max # of queue pairs supported by the device */
  95        u16 max_queue_pairs;
  96
  97        /* # of queue pairs currently used by the driver */
  98        u16 curr_queue_pairs;
  99
 100        /* I like... big packets and I cannot lie! */
 101        bool big_packets;
 102
 103        /* Host will merge rx buffers for big packets (shake it! shake it!) */
 104        bool mergeable_rx_bufs;
 105
 106        /* Has control virtqueue */
 107        bool has_cvq;
 108
 109        /* Host can handle any s/g split between our header and packet data */
 110        bool any_header_sg;
 111
 112        /* enable config space updates */
 113        bool config_enable;
 114
 115        /* Active statistics */
 116        struct virtnet_stats __percpu *stats;
 117
 118        /* Work struct for refilling if we run low on memory. */
 119        struct delayed_work refill;
 120
 121        /* Work struct for config space updates */
 122        struct work_struct config_work;
 123
 124        /* Lock for config space updates */
 125        struct mutex config_lock;
 126
 127        /* Does the affinity hint is set for virtqueues? */
 128        bool affinity_hint_set;
 129
 130        /* Per-cpu variable to show the mapping from CPU to virtqueue */
 131        int __percpu *vq_index;
 132
 133        /* CPU hot plug notifier */
 134        struct notifier_block nb;
 135};
 136
 137struct skb_vnet_hdr {
 138        union {
 139                struct virtio_net_hdr hdr;
 140                struct virtio_net_hdr_mrg_rxbuf mhdr;
 141        };
 142};
 143
 144struct padded_vnet_hdr {
 145        struct virtio_net_hdr hdr;
 146        /*
 147         * virtio_net_hdr should be in a separated sg buffer because of a
 148         * QEMU bug, and data sg buffer shares same page with this header sg.
 149         * This padding makes next sg 16 byte aligned after virtio_net_hdr.
 150         */
 151        char padding[6];
 152};
 153
 154/* Converting between virtqueue no. and kernel tx/rx queue no.
 155 * 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq
 156 */
 157static int vq2txq(struct virtqueue *vq)
 158{
 159        return (vq->index - 1) / 2;
 160}
 161
 162static int txq2vq(int txq)
 163{
 164        return txq * 2 + 1;
 165}
 166
 167static int vq2rxq(struct virtqueue *vq)
 168{
 169        return vq->index / 2;
 170}
 171
 172static int rxq2vq(int rxq)
 173{
 174        return rxq * 2;
 175}
 176
 177static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
 178{
 179        return (struct skb_vnet_hdr *)skb->cb;
 180}
 181
 182/*
 183 * private is used to chain pages for big packets, put the whole
 184 * most recent used list in the beginning for reuse
 185 */
 186static void give_pages(struct receive_queue *rq, struct page *page)
 187{
 188        struct page *end;
 189
 190        /* Find end of list, sew whole thing into vi->rq.pages. */
 191        for (end = page; end->private; end = (struct page *)end->private);
 192        end->private = (unsigned long)rq->pages;
 193        rq->pages = page;
 194}
 195
 196static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
 197{
 198        struct page *p = rq->pages;
 199
 200        if (p) {
 201                rq->pages = (struct page *)p->private;
 202                /* clear private here, it is used to chain pages */
 203                p->private = 0;
 204        } else
 205                p = alloc_page(gfp_mask);
 206        return p;
 207}
 208
 209static void skb_xmit_done(struct virtqueue *vq)
 210{
 211        struct virtnet_info *vi = vq->vdev->priv;
 212
 213        /* Suppress further interrupts. */
 214        virtqueue_disable_cb(vq);
 215
 216        /* We were probably waiting for more output buffers. */
 217        netif_wake_subqueue(vi->dev, vq2txq(vq));
 218}
 219
 220static void set_skb_frag(struct sk_buff *skb, struct page *page,
 221                         unsigned int offset, unsigned int *len)
 222{
 223        int size = min((unsigned)PAGE_SIZE - offset, *len);
 224        int i = skb_shinfo(skb)->nr_frags;
 225
 226        __skb_fill_page_desc(skb, i, page, offset, size);
 227
 228        skb->data_len += size;
 229        skb->len += size;
 230        skb->truesize += PAGE_SIZE;
 231        skb_shinfo(skb)->nr_frags++;
 232        skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
 233        *len -= size;
 234}
 235
 236/* Called from bottom half context */
 237static struct sk_buff *page_to_skb(struct receive_queue *rq,
 238                                   struct page *page, unsigned int len)
 239{
 240        struct virtnet_info *vi = rq->vq->vdev->priv;
 241        struct sk_buff *skb;
 242        struct skb_vnet_hdr *hdr;
 243        unsigned int copy, hdr_len, offset;
 244        char *p;
 245
 246        p = page_address(page);
 247
 248        /* copy small packet so we can reuse these pages for small data */
 249        skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
 250        if (unlikely(!skb))
 251                return NULL;
 252
 253        hdr = skb_vnet_hdr(skb);
 254
 255        if (vi->mergeable_rx_bufs) {
 256                hdr_len = sizeof hdr->mhdr;
 257                offset = hdr_len;
 258        } else {
 259                hdr_len = sizeof hdr->hdr;
 260                offset = sizeof(struct padded_vnet_hdr);
 261        }
 262
 263        memcpy(hdr, p, hdr_len);
 264
 265        len -= hdr_len;
 266        p += offset;
 267
 268        copy = len;
 269        if (copy > skb_tailroom(skb))
 270                copy = skb_tailroom(skb);
 271        memcpy(skb_put(skb, copy), p, copy);
 272
 273        len -= copy;
 274        offset += copy;
 275
 276        /*
 277         * Verify that we can indeed put this data into a skb.
 278         * This is here to handle cases when the device erroneously
 279         * tries to receive more than is possible. This is usually
 280         * the case of a broken device.
 281         */
 282        if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
 283                net_dbg_ratelimited("%s: too much data\n", skb->dev->name);
 284                dev_kfree_skb(skb);
 285                return NULL;
 286        }
 287
 288        while (len) {
 289                set_skb_frag(skb, page, offset, &len);
 290                page = (struct page *)page->private;
 291                offset = 0;
 292        }
 293
 294        if (page)
 295                give_pages(rq, page);
 296
 297        return skb;
 298}
 299
 300static int receive_mergeable(struct receive_queue *rq, struct sk_buff *skb)
 301{
 302        struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 303        struct page *page;
 304        int num_buf, i, len;
 305
 306        num_buf = hdr->mhdr.num_buffers;
 307        while (--num_buf) {
 308                i = skb_shinfo(skb)->nr_frags;
 309                if (i >= MAX_SKB_FRAGS) {
 310                        pr_debug("%s: packet too long\n", skb->dev->name);
 311                        skb->dev->stats.rx_length_errors++;
 312                        return -EINVAL;
 313                }
 314                page = virtqueue_get_buf(rq->vq, &len);
 315                if (!page) {
 316                        pr_debug("%s: rx error: %d buffers missing\n",
 317                                 skb->dev->name, hdr->mhdr.num_buffers);
 318                        skb->dev->stats.rx_length_errors++;
 319                        return -EINVAL;
 320                }
 321
 322                if (len > PAGE_SIZE)
 323                        len = PAGE_SIZE;
 324
 325                set_skb_frag(skb, page, 0, &len);
 326
 327                --rq->num;
 328        }
 329        return 0;
 330}
 331
 332static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
 333{
 334        struct virtnet_info *vi = rq->vq->vdev->priv;
 335        struct net_device *dev = vi->dev;
 336        struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
 337        struct sk_buff *skb;
 338        struct page *page;
 339        struct skb_vnet_hdr *hdr;
 340
 341        if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
 342                pr_debug("%s: short packet %i\n", dev->name, len);
 343                dev->stats.rx_length_errors++;
 344                if (vi->mergeable_rx_bufs || vi->big_packets)
 345                        give_pages(rq, buf);
 346                else
 347                        dev_kfree_skb(buf);
 348                return;
 349        }
 350
 351        if (!vi->mergeable_rx_bufs && !vi->big_packets) {
 352                skb = buf;
 353                len -= sizeof(struct virtio_net_hdr);
 354                skb_trim(skb, len);
 355        } else {
 356                page = buf;
 357                skb = page_to_skb(rq, page, len);
 358                if (unlikely(!skb)) {
 359                        dev->stats.rx_dropped++;
 360                        give_pages(rq, page);
 361                        return;
 362                }
 363                if (vi->mergeable_rx_bufs)
 364                        if (receive_mergeable(rq, skb)) {
 365                                dev_kfree_skb(skb);
 366                                return;
 367                        }
 368        }
 369
 370        hdr = skb_vnet_hdr(skb);
 371
 372        u64_stats_update_begin(&stats->rx_syncp);
 373        stats->rx_bytes += skb->len;
 374        stats->rx_packets++;
 375        u64_stats_update_end(&stats->rx_syncp);
 376
 377        if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 378                pr_debug("Needs csum!\n");
 379                if (!skb_partial_csum_set(skb,
 380                                          hdr->hdr.csum_start,
 381                                          hdr->hdr.csum_offset))
 382                        goto frame_err;
 383        } else if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID) {
 384                skb->ip_summed = CHECKSUM_UNNECESSARY;
 385        }
 386
 387        skb->protocol = eth_type_trans(skb, dev);
 388        pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
 389                 ntohs(skb->protocol), skb->len, skb->pkt_type);
 390
 391        if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 392                pr_debug("GSO!\n");
 393                switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 394                case VIRTIO_NET_HDR_GSO_TCPV4:
 395                        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 396                        break;
 397                case VIRTIO_NET_HDR_GSO_UDP:
 398                        skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 399                        break;
 400                case VIRTIO_NET_HDR_GSO_TCPV6:
 401                        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 402                        break;
 403                default:
 404                        net_warn_ratelimited("%s: bad gso type %u.\n",
 405                                             dev->name, hdr->hdr.gso_type);
 406                        goto frame_err;
 407                }
 408
 409                if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 410                        skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 411
 412                skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
 413                if (skb_shinfo(skb)->gso_size == 0) {
 414                        net_warn_ratelimited("%s: zero gso size.\n", dev->name);
 415                        goto frame_err;
 416                }
 417
 418                /* Header must be checked, and gso_segs computed. */
 419                skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 420                skb_shinfo(skb)->gso_segs = 0;
 421        }
 422
 423        netif_receive_skb(skb);
 424        return;
 425
 426frame_err:
 427        dev->stats.rx_frame_errors++;
 428        dev_kfree_skb(skb);
 429}
 430
 431static int add_recvbuf_small(struct receive_queue *rq, gfp_t gfp)
 432{
 433        struct virtnet_info *vi = rq->vq->vdev->priv;
 434        struct sk_buff *skb;
 435        struct skb_vnet_hdr *hdr;
 436        int err;
 437
 438        skb = __netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN, gfp);
 439        if (unlikely(!skb))
 440                return -ENOMEM;
 441
 442        skb_put(skb, MAX_PACKET_LEN);
 443
 444        hdr = skb_vnet_hdr(skb);
 445        sg_set_buf(rq->sg, &hdr->hdr, sizeof hdr->hdr);
 446
 447        skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
 448
 449        err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp);
 450        if (err < 0)
 451                dev_kfree_skb(skb);
 452
 453        return err;
 454}
 455
 456static int add_recvbuf_big(struct receive_queue *rq, gfp_t gfp)
 457{
 458        struct page *first, *list = NULL;
 459        char *p;
 460        int i, err, offset;
 461
 462        /* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */
 463        for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
 464                first = get_a_page(rq, gfp);
 465                if (!first) {
 466                        if (list)
 467                                give_pages(rq, list);
 468                        return -ENOMEM;
 469                }
 470                sg_set_buf(&rq->sg[i], page_address(first), PAGE_SIZE);
 471
 472                /* chain new page in list head to match sg */
 473                first->private = (unsigned long)list;
 474                list = first;
 475        }
 476
 477        first = get_a_page(rq, gfp);
 478        if (!first) {
 479                give_pages(rq, list);
 480                return -ENOMEM;
 481        }
 482        p = page_address(first);
 483
 484        /* rq->sg[0], rq->sg[1] share the same page */
 485        /* a separated rq->sg[0] for virtio_net_hdr only due to QEMU bug */
 486        sg_set_buf(&rq->sg[0], p, sizeof(struct virtio_net_hdr));
 487
 488        /* rq->sg[1] for data packet, from offset */
 489        offset = sizeof(struct padded_vnet_hdr);
 490        sg_set_buf(&rq->sg[1], p + offset, PAGE_SIZE - offset);
 491
 492        /* chain first in list head */
 493        first->private = (unsigned long)list;
 494        err = virtqueue_add_inbuf(rq->vq, rq->sg, MAX_SKB_FRAGS + 2,
 495                                  first, gfp);
 496        if (err < 0)
 497                give_pages(rq, first);
 498
 499        return err;
 500}
 501
 502static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
 503{
 504        struct page *page;
 505        int err;
 506
 507        page = get_a_page(rq, gfp);
 508        if (!page)
 509                return -ENOMEM;
 510
 511        sg_init_one(rq->sg, page_address(page), PAGE_SIZE);
 512
 513        err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, page, gfp);
 514        if (err < 0)
 515                give_pages(rq, page);
 516
 517        return err;
 518}
 519
 520/*
 521 * Returns false if we couldn't fill entirely (OOM).
 522 *
 523 * Normally run in the receive path, but can also be run from ndo_open
 524 * before we're receiving packets, or from refill_work which is
 525 * careful to disable receiving (using napi_disable).
 526 */
 527static bool try_fill_recv(struct receive_queue *rq, gfp_t gfp)
 528{
 529        struct virtnet_info *vi = rq->vq->vdev->priv;
 530        int err;
 531        bool oom;
 532
 533        do {
 534                if (vi->mergeable_rx_bufs)
 535                        err = add_recvbuf_mergeable(rq, gfp);
 536                else if (vi->big_packets)
 537                        err = add_recvbuf_big(rq, gfp);
 538                else
 539                        err = add_recvbuf_small(rq, gfp);
 540
 541                oom = err == -ENOMEM;
 542                if (err)
 543                        break;
 544                ++rq->num;
 545        } while (rq->vq->num_free);
 546        if (unlikely(rq->num > rq->max))
 547                rq->max = rq->num;
 548        virtqueue_kick(rq->vq);
 549        return !oom;
 550}
 551
 552static void skb_recv_done(struct virtqueue *rvq)
 553{
 554        struct virtnet_info *vi = rvq->vdev->priv;
 555        struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
 556
 557        /* Schedule NAPI, Suppress further interrupts if successful. */
 558        if (napi_schedule_prep(&rq->napi)) {
 559                virtqueue_disable_cb(rvq);
 560                __napi_schedule(&rq->napi);
 561        }
 562}
 563
 564static void virtnet_napi_enable(struct receive_queue *rq)
 565{
 566        napi_enable(&rq->napi);
 567
 568        /* If all buffers were filled by other side before we napi_enabled, we
 569         * won't get another interrupt, so process any outstanding packets
 570         * now.  virtnet_poll wants re-enable the queue, so we disable here.
 571         * We synchronize against interrupts via NAPI_STATE_SCHED */
 572        if (napi_schedule_prep(&rq->napi)) {
 573                virtqueue_disable_cb(rq->vq);
 574                local_bh_disable();
 575                __napi_schedule(&rq->napi);
 576                local_bh_enable();
 577        }
 578}
 579
 580static void refill_work(struct work_struct *work)
 581{
 582        struct virtnet_info *vi =
 583                container_of(work, struct virtnet_info, refill.work);
 584        bool still_empty;
 585        int i;
 586
 587        for (i = 0; i < vi->curr_queue_pairs; i++) {
 588                struct receive_queue *rq = &vi->rq[i];
 589
 590                napi_disable(&rq->napi);
 591                still_empty = !try_fill_recv(rq, GFP_KERNEL);
 592                virtnet_napi_enable(rq);
 593
 594                /* In theory, this can happen: if we don't get any buffers in
 595                 * we will *never* try to fill again.
 596                 */
 597                if (still_empty)
 598                        schedule_delayed_work(&vi->refill, HZ/2);
 599        }
 600}
 601
 602static int virtnet_poll(struct napi_struct *napi, int budget)
 603{
 604        struct receive_queue *rq =
 605                container_of(napi, struct receive_queue, napi);
 606        struct virtnet_info *vi = rq->vq->vdev->priv;
 607        void *buf;
 608        unsigned int r, len, received = 0;
 609
 610again:
 611        while (received < budget &&
 612               (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
 613                receive_buf(rq, buf, len);
 614                --rq->num;
 615                received++;
 616        }
 617
 618        if (rq->num < rq->max / 2) {
 619                if (!try_fill_recv(rq, GFP_ATOMIC))
 620                        schedule_delayed_work(&vi->refill, 0);
 621        }
 622
 623        /* Out of packets? */
 624        if (received < budget) {
 625                r = virtqueue_enable_cb_prepare(rq->vq);
 626                napi_complete(napi);
 627                if (unlikely(virtqueue_poll(rq->vq, r)) &&
 628                    napi_schedule_prep(napi)) {
 629                        virtqueue_disable_cb(rq->vq);
 630                        __napi_schedule(napi);
 631                        goto again;
 632                }
 633        }
 634
 635        return received;
 636}
 637
 638static int virtnet_open(struct net_device *dev)
 639{
 640        struct virtnet_info *vi = netdev_priv(dev);
 641        int i;
 642
 643        for (i = 0; i < vi->max_queue_pairs; i++) {
 644                if (i < vi->curr_queue_pairs)
 645                        /* Make sure we have some buffers: if oom use wq. */
 646                        if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
 647                                schedule_delayed_work(&vi->refill, 0);
 648                virtnet_napi_enable(&vi->rq[i]);
 649        }
 650
 651        return 0;
 652}
 653
 654static void free_old_xmit_skbs(struct send_queue *sq)
 655{
 656        struct sk_buff *skb;
 657        unsigned int len;
 658        struct virtnet_info *vi = sq->vq->vdev->priv;
 659        struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
 660
 661        while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {
 662                pr_debug("Sent skb %p\n", skb);
 663
 664                u64_stats_update_begin(&stats->tx_syncp);
 665                stats->tx_bytes += skb->len;
 666                stats->tx_packets++;
 667                u64_stats_update_end(&stats->tx_syncp);
 668
 669                dev_kfree_skb_any(skb);
 670        }
 671}
 672
 673static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
 674{
 675        struct skb_vnet_hdr *hdr;
 676        const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 677        struct virtnet_info *vi = sq->vq->vdev->priv;
 678        unsigned num_sg;
 679        unsigned hdr_len;
 680        bool can_push;
 681
 682        pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
 683        if (vi->mergeable_rx_bufs)
 684                hdr_len = sizeof hdr->mhdr;
 685        else
 686                hdr_len = sizeof hdr->hdr;
 687
 688        can_push = vi->any_header_sg &&
 689                !((unsigned long)skb->data & (__alignof__(*hdr) - 1)) &&
 690                !skb_header_cloned(skb) && skb_headroom(skb) >= hdr_len;
 691        /* Even if we can, don't push here yet as this would skew
 692         * csum_start offset below. */
 693        if (can_push)
 694                hdr = (struct skb_vnet_hdr *)(skb->data - hdr_len);
 695        else
 696                hdr = skb_vnet_hdr(skb);
 697
 698        if (skb->ip_summed == CHECKSUM_PARTIAL) {
 699                hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 700                hdr->hdr.csum_start = skb_checksum_start_offset(skb);
 701                hdr->hdr.csum_offset = skb->csum_offset;
 702        } else {
 703                hdr->hdr.flags = 0;
 704                hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
 705        }
 706
 707        if (skb_is_gso(skb)) {
 708                hdr->hdr.hdr_len = skb_headlen(skb);
 709                hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
 710                if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 711                        hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 712                else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 713                        hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 714                else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 715                        hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 716                else
 717                        BUG();
 718                if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
 719                        hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 720        } else {
 721                hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 722                hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
 723        }
 724
 725        if (vi->mergeable_rx_bufs)
 726                hdr->mhdr.num_buffers = 0;
 727
 728        if (can_push) {
 729                __skb_push(skb, hdr_len);
 730                num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len);
 731                /* Pull header back to avoid skew in tx bytes calculations. */
 732                __skb_pull(skb, hdr_len);
 733        } else {
 734                sg_set_buf(sq->sg, hdr, hdr_len);
 735                num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
 736        }
 737        return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC);
 738}
 739
 740static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 741{
 742        struct virtnet_info *vi = netdev_priv(dev);
 743        int qnum = skb_get_queue_mapping(skb);
 744        struct send_queue *sq = &vi->sq[qnum];
 745        int err;
 746
 747        /* Free up any pending old buffers before queueing new ones. */
 748        free_old_xmit_skbs(sq);
 749
 750        /* Try to transmit */
 751        err = xmit_skb(sq, skb);
 752
 753        /* This should not happen! */
 754        if (unlikely(err)) {
 755                dev->stats.tx_fifo_errors++;
 756                if (net_ratelimit())
 757                        dev_warn(&dev->dev,
 758                                 "Unexpected TXQ (%d) queue failure: %d\n", qnum, err);
 759                dev->stats.tx_dropped++;
 760                kfree_skb(skb);
 761                return NETDEV_TX_OK;
 762        }
 763        virtqueue_kick(sq->vq);
 764
 765        /* Don't wait up for transmitted skbs to be freed. */
 766        skb_orphan(skb);
 767        nf_reset(skb);
 768
 769        /* Apparently nice girls don't return TX_BUSY; stop the queue
 770         * before it gets out of hand.  Naturally, this wastes entries. */
 771        if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
 772                netif_stop_subqueue(dev, qnum);
 773                if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
 774                        /* More just got used, free them then recheck. */
 775                        free_old_xmit_skbs(sq);
 776                        if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
 777                                netif_start_subqueue(dev, qnum);
 778                                virtqueue_disable_cb(sq->vq);
 779                        }
 780                }
 781        }
 782
 783        return NETDEV_TX_OK;
 784}
 785
 786/*
 787 * Send command via the control virtqueue and check status.  Commands
 788 * supported by the hypervisor, as indicated by feature bits, should
 789 * never fail unless improperly formated.
 790 */
 791static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
 792                                 struct scatterlist *out,
 793                                 struct scatterlist *in)
 794{
 795        struct scatterlist *sgs[4], hdr, stat;
 796        struct virtio_net_ctrl_hdr ctrl;
 797        virtio_net_ctrl_ack status = ~0;
 798        unsigned out_num = 0, in_num = 0, tmp;
 799
 800        /* Caller should know better */
 801        BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
 802
 803        ctrl.class = class;
 804        ctrl.cmd = cmd;
 805        /* Add header */
 806        sg_init_one(&hdr, &ctrl, sizeof(ctrl));
 807        sgs[out_num++] = &hdr;
 808
 809        if (out)
 810                sgs[out_num++] = out;
 811        if (in)
 812                sgs[out_num + in_num++] = in;
 813
 814        /* Add return status. */
 815        sg_init_one(&stat, &status, sizeof(status));
 816        sgs[out_num + in_num++] = &stat;
 817
 818        BUG_ON(out_num + in_num > ARRAY_SIZE(sgs));
 819        BUG_ON(virtqueue_add_sgs(vi->cvq, sgs, out_num, in_num, vi, GFP_ATOMIC)
 820               < 0);
 821
 822        virtqueue_kick(vi->cvq);
 823
 824        /* Spin for a response, the kick causes an ioport write, trapping
 825         * into the hypervisor, so the request should be handled immediately.
 826         */
 827        while (!virtqueue_get_buf(vi->cvq, &tmp))
 828                cpu_relax();
 829
 830        return status == VIRTIO_NET_OK;
 831}
 832
 833static int virtnet_set_mac_address(struct net_device *dev, void *p)
 834{
 835        struct virtnet_info *vi = netdev_priv(dev);
 836        struct virtio_device *vdev = vi->vdev;
 837        int ret;
 838        struct sockaddr *addr = p;
 839        struct scatterlist sg;
 840
 841        ret = eth_prepare_mac_addr_change(dev, p);
 842        if (ret)
 843                return ret;
 844
 845        if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
 846                sg_init_one(&sg, addr->sa_data, dev->addr_len);
 847                if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
 848                                          VIRTIO_NET_CTRL_MAC_ADDR_SET,
 849                                          &sg, NULL)) {
 850                        dev_warn(&vdev->dev,
 851                                 "Failed to set mac address by vq command.\n");
 852                        return -EINVAL;
 853                }
 854        } else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
 855                vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
 856                                  addr->sa_data, dev->addr_len);
 857        }
 858
 859        eth_commit_mac_addr_change(dev, p);
 860
 861        return 0;
 862}
 863
 864static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
 865                                               struct rtnl_link_stats64 *tot)
 866{
 867        struct virtnet_info *vi = netdev_priv(dev);
 868        int cpu;
 869        unsigned int start;
 870
 871        for_each_possible_cpu(cpu) {
 872                struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
 873                u64 tpackets, tbytes, rpackets, rbytes;
 874
 875                do {
 876                        start = u64_stats_fetch_begin_bh(&stats->tx_syncp);
 877                        tpackets = stats->tx_packets;
 878                        tbytes   = stats->tx_bytes;
 879                } while (u64_stats_fetch_retry_bh(&stats->tx_syncp, start));
 880
 881                do {
 882                        start = u64_stats_fetch_begin_bh(&stats->rx_syncp);
 883                        rpackets = stats->rx_packets;
 884                        rbytes   = stats->rx_bytes;
 885                } while (u64_stats_fetch_retry_bh(&stats->rx_syncp, start));
 886
 887                tot->rx_packets += rpackets;
 888                tot->tx_packets += tpackets;
 889                tot->rx_bytes   += rbytes;
 890                tot->tx_bytes   += tbytes;
 891        }
 892
 893        tot->tx_dropped = dev->stats.tx_dropped;
 894        tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
 895        tot->rx_dropped = dev->stats.rx_dropped;
 896        tot->rx_length_errors = dev->stats.rx_length_errors;
 897        tot->rx_frame_errors = dev->stats.rx_frame_errors;
 898
 899        return tot;
 900}
 901
 902#ifdef CONFIG_NET_POLL_CONTROLLER
 903static void virtnet_netpoll(struct net_device *dev)
 904{
 905        struct virtnet_info *vi = netdev_priv(dev);
 906        int i;
 907
 908        for (i = 0; i < vi->curr_queue_pairs; i++)
 909                napi_schedule(&vi->rq[i].napi);
 910}
 911#endif
 912
 913static void virtnet_ack_link_announce(struct virtnet_info *vi)
 914{
 915        rtnl_lock();
 916        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
 917                                  VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL, NULL))
 918                dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
 919        rtnl_unlock();
 920}
 921
 922static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
 923{
 924        struct scatterlist sg;
 925        struct virtio_net_ctrl_mq s;
 926        struct net_device *dev = vi->dev;
 927
 928        if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
 929                return 0;
 930
 931        s.virtqueue_pairs = queue_pairs;
 932        sg_init_one(&sg, &s, sizeof(s));
 933
 934        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
 935                                  VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg, NULL)) {
 936                dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
 937                         queue_pairs);
 938                return -EINVAL;
 939        } else {
 940                vi->curr_queue_pairs = queue_pairs;
 941                /* virtnet_open() will refill when device is going to up. */
 942                if (dev->flags & IFF_UP)
 943                        schedule_delayed_work(&vi->refill, 0);
 944        }
 945
 946        return 0;
 947}
 948
 949static int virtnet_close(struct net_device *dev)
 950{
 951        struct virtnet_info *vi = netdev_priv(dev);
 952        int i;
 953
 954        /* Make sure refill_work doesn't re-enable napi! */
 955        cancel_delayed_work_sync(&vi->refill);
 956
 957        for (i = 0; i < vi->max_queue_pairs; i++)
 958                napi_disable(&vi->rq[i].napi);
 959
 960        return 0;
 961}
 962
 963static void virtnet_set_rx_mode(struct net_device *dev)
 964{
 965        struct virtnet_info *vi = netdev_priv(dev);
 966        struct scatterlist sg[2];
 967        u8 promisc, allmulti;
 968        struct virtio_net_ctrl_mac *mac_data;
 969        struct netdev_hw_addr *ha;
 970        int uc_count;
 971        int mc_count;
 972        void *buf;
 973        int i;
 974
 975        /* We can't dynamicaly set ndo_set_rx_mode, so return gracefully */
 976        if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
 977                return;
 978
 979        promisc = ((dev->flags & IFF_PROMISC) != 0);
 980        allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
 981
 982        sg_init_one(sg, &promisc, sizeof(promisc));
 983
 984        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 985                                  VIRTIO_NET_CTRL_RX_PROMISC,
 986                                  sg, NULL))
 987                dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
 988                         promisc ? "en" : "dis");
 989
 990        sg_init_one(sg, &allmulti, sizeof(allmulti));
 991
 992        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 993                                  VIRTIO_NET_CTRL_RX_ALLMULTI,
 994                                  sg, NULL))
 995                dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
 996                         allmulti ? "en" : "dis");
 997
 998        uc_count = netdev_uc_count(dev);
 999        mc_count = netdev_mc_count(dev);
1000        /* MAC filter - use one buffer for both lists */
1001        buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
1002                      (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
1003        mac_data = buf;
1004        if (!buf)
1005                return;
1006
1007        sg_init_table(sg, 2);
1008
1009        /* Store the unicast list and count in the front of the buffer */
1010        mac_data->entries = uc_count;
1011        i = 0;
1012        netdev_for_each_uc_addr(ha, dev)
1013                memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1014
1015        sg_set_buf(&sg[0], mac_data,
1016                   sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
1017
1018        /* multicast list and count fill the end */
1019        mac_data = (void *)&mac_data->macs[uc_count][0];
1020
1021        mac_data->entries = mc_count;
1022        i = 0;
1023        netdev_for_each_mc_addr(ha, dev)
1024                memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1025
1026        sg_set_buf(&sg[1], mac_data,
1027                   sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
1028
1029        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1030                                  VIRTIO_NET_CTRL_MAC_TABLE_SET,
1031                                  sg, NULL))
1032                dev_warn(&dev->dev, "Failed to set MAC fitler table.\n");
1033
1034        kfree(buf);
1035}
1036
1037static int virtnet_vlan_rx_add_vid(struct net_device *dev,
1038                                   __be16 proto, u16 vid)
1039{
1040        struct virtnet_info *vi = netdev_priv(dev);
1041        struct scatterlist sg;
1042
1043        sg_init_one(&sg, &vid, sizeof(vid));
1044
1045        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1046                                  VIRTIO_NET_CTRL_VLAN_ADD, &sg, NULL))
1047                dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
1048        return 0;
1049}
1050
1051static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
1052                                    __be16 proto, u16 vid)
1053{
1054        struct virtnet_info *vi = netdev_priv(dev);
1055        struct scatterlist sg;
1056
1057        sg_init_one(&sg, &vid, sizeof(vid));
1058
1059        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1060                                  VIRTIO_NET_CTRL_VLAN_DEL, &sg, NULL))
1061                dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
1062        return 0;
1063}
1064
1065static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
1066{
1067        int i;
1068        int cpu;
1069
1070        if (vi->affinity_hint_set) {
1071                for (i = 0; i < vi->max_queue_pairs; i++) {
1072                        virtqueue_set_affinity(vi->rq[i].vq, -1);
1073                        virtqueue_set_affinity(vi->sq[i].vq, -1);
1074                }
1075
1076                vi->affinity_hint_set = false;
1077        }
1078
1079        i = 0;
1080        for_each_online_cpu(cpu) {
1081                if (cpu == hcpu) {
1082                        *per_cpu_ptr(vi->vq_index, cpu) = -1;
1083                } else {
1084                        *per_cpu_ptr(vi->vq_index, cpu) =
1085                                ++i % vi->curr_queue_pairs;
1086                }
1087        }
1088}
1089
1090static void virtnet_set_affinity(struct virtnet_info *vi)
1091{
1092        int i;
1093        int cpu;
1094
1095        /* In multiqueue mode, when the number of cpu is equal to the number of
1096         * queue pairs, we let the queue pairs to be private to one cpu by
1097         * setting the affinity hint to eliminate the contention.
1098         */
1099        if (vi->curr_queue_pairs == 1 ||
1100            vi->max_queue_pairs != num_online_cpus()) {
1101                virtnet_clean_affinity(vi, -1);
1102                return;
1103        }
1104
1105        i = 0;
1106        for_each_online_cpu(cpu) {
1107                virtqueue_set_affinity(vi->rq[i].vq, cpu);
1108                virtqueue_set_affinity(vi->sq[i].vq, cpu);
1109                *per_cpu_ptr(vi->vq_index, cpu) = i;
1110                i++;
1111        }
1112
1113        vi->affinity_hint_set = true;
1114}
1115
1116static int virtnet_cpu_callback(struct notifier_block *nfb,
1117                                unsigned long action, void *hcpu)
1118{
1119        struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
1120
1121        mutex_lock(&vi->config_lock);
1122
1123        if (!vi->config_enable)
1124                goto done;
1125
1126        switch(action & ~CPU_TASKS_FROZEN) {
1127        case CPU_ONLINE:
1128        case CPU_DOWN_FAILED:
1129        case CPU_DEAD:
1130                virtnet_set_affinity(vi);
1131                break;
1132        case CPU_DOWN_PREPARE:
1133                virtnet_clean_affinity(vi, (long)hcpu);
1134                break;
1135        default:
1136                break;
1137        }
1138
1139done:
1140        mutex_unlock(&vi->config_lock);
1141        return NOTIFY_OK;
1142}
1143
1144static void virtnet_get_ringparam(struct net_device *dev,
1145                                struct ethtool_ringparam *ring)
1146{
1147        struct virtnet_info *vi = netdev_priv(dev);
1148
1149        ring->rx_max_pending = virtqueue_get_vring_size(vi->rq[0].vq);
1150        ring->tx_max_pending = virtqueue_get_vring_size(vi->sq[0].vq);
1151        ring->rx_pending = ring->rx_max_pending;
1152        ring->tx_pending = ring->tx_max_pending;
1153}
1154
1155
1156static void virtnet_get_drvinfo(struct net_device *dev,
1157                                struct ethtool_drvinfo *info)
1158{
1159        struct virtnet_info *vi = netdev_priv(dev);
1160        struct virtio_device *vdev = vi->vdev;
1161
1162        strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
1163        strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
1164        strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
1165
1166}
1167
1168/* TODO: Eliminate OOO packets during switching */
1169static int virtnet_set_channels(struct net_device *dev,
1170                                struct ethtool_channels *channels)
1171{
1172        struct virtnet_info *vi = netdev_priv(dev);
1173        u16 queue_pairs = channels->combined_count;
1174        int err;
1175
1176        /* We don't support separate rx/tx channels.
1177         * We don't allow setting 'other' channels.
1178         */
1179        if (channels->rx_count || channels->tx_count || channels->other_count)
1180                return -EINVAL;
1181
1182        if (queue_pairs > vi->max_queue_pairs)
1183                return -EINVAL;
1184
1185        get_online_cpus();
1186        err = virtnet_set_queues(vi, queue_pairs);
1187        if (!err) {
1188                netif_set_real_num_tx_queues(dev, queue_pairs);
1189                netif_set_real_num_rx_queues(dev, queue_pairs);
1190
1191                virtnet_set_affinity(vi);
1192        }
1193        put_online_cpus();
1194
1195        return err;
1196}
1197
1198static void virtnet_get_channels(struct net_device *dev,
1199                                 struct ethtool_channels *channels)
1200{
1201        struct virtnet_info *vi = netdev_priv(dev);
1202
1203        channels->combined_count = vi->curr_queue_pairs;
1204        channels->max_combined = vi->max_queue_pairs;
1205        channels->max_other = 0;
1206        channels->rx_count = 0;
1207        channels->tx_count = 0;
1208        channels->other_count = 0;
1209}
1210
1211static const struct ethtool_ops virtnet_ethtool_ops = {
1212        .get_drvinfo = virtnet_get_drvinfo,
1213        .get_link = ethtool_op_get_link,
1214        .get_ringparam = virtnet_get_ringparam,
1215        .set_channels = virtnet_set_channels,
1216        .get_channels = virtnet_get_channels,
1217};
1218
1219#define MIN_MTU 68
1220#define MAX_MTU 65535
1221
1222static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
1223{
1224        if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
1225                return -EINVAL;
1226        dev->mtu = new_mtu;
1227        return 0;
1228}
1229
1230/* To avoid contending a lock hold by a vcpu who would exit to host, select the
1231 * txq based on the processor id.
1232 */
1233static u16 virtnet_select_queue(struct net_device *dev, struct sk_buff *skb)
1234{
1235        int txq;
1236        struct virtnet_info *vi = netdev_priv(dev);
1237
1238        if (skb_rx_queue_recorded(skb)) {
1239                txq = skb_get_rx_queue(skb);
1240        } else {
1241                txq = *__this_cpu_ptr(vi->vq_index);
1242                if (txq == -1)
1243                        txq = 0;
1244        }
1245
1246        while (unlikely(txq >= dev->real_num_tx_queues))
1247                txq -= dev->real_num_tx_queues;
1248
1249        return txq;
1250}
1251
1252static const struct net_device_ops virtnet_netdev = {
1253        .ndo_open            = virtnet_open,
1254        .ndo_stop            = virtnet_close,
1255        .ndo_start_xmit      = start_xmit,
1256        .ndo_validate_addr   = eth_validate_addr,
1257        .ndo_set_mac_address = virtnet_set_mac_address,
1258        .ndo_set_rx_mode     = virtnet_set_rx_mode,
1259        .ndo_change_mtu      = virtnet_change_mtu,
1260        .ndo_get_stats64     = virtnet_stats,
1261        .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
1262        .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
1263        .ndo_select_queue     = virtnet_select_queue,
1264#ifdef CONFIG_NET_POLL_CONTROLLER
1265        .ndo_poll_controller = virtnet_netpoll,
1266#endif
1267};
1268
1269static void virtnet_config_changed_work(struct work_struct *work)
1270{
1271        struct virtnet_info *vi =
1272                container_of(work, struct virtnet_info, config_work);
1273        u16 v;
1274
1275        mutex_lock(&vi->config_lock);
1276        if (!vi->config_enable)
1277                goto done;
1278
1279        if (virtio_config_val(vi->vdev, VIRTIO_NET_F_STATUS,
1280                              offsetof(struct virtio_net_config, status),
1281                              &v) < 0)
1282                goto done;
1283
1284        if (v & VIRTIO_NET_S_ANNOUNCE) {
1285                netdev_notify_peers(vi->dev);
1286                virtnet_ack_link_announce(vi);
1287        }
1288
1289        /* Ignore unknown (future) status bits */
1290        v &= VIRTIO_NET_S_LINK_UP;
1291
1292        if (vi->status == v)
1293                goto done;
1294
1295        vi->status = v;
1296
1297        if (vi->status & VIRTIO_NET_S_LINK_UP) {
1298                netif_carrier_on(vi->dev);
1299                netif_tx_wake_all_queues(vi->dev);
1300        } else {
1301                netif_carrier_off(vi->dev);
1302                netif_tx_stop_all_queues(vi->dev);
1303        }
1304done:
1305        mutex_unlock(&vi->config_lock);
1306}
1307
1308static void virtnet_config_changed(struct virtio_device *vdev)
1309{
1310        struct virtnet_info *vi = vdev->priv;
1311
1312        schedule_work(&vi->config_work);
1313}
1314
1315static void virtnet_free_queues(struct virtnet_info *vi)
1316{
1317        kfree(vi->rq);
1318        kfree(vi->sq);
1319}
1320
1321static void free_receive_bufs(struct virtnet_info *vi)
1322{
1323        int i;
1324
1325        for (i = 0; i < vi->max_queue_pairs; i++) {
1326                while (vi->rq[i].pages)
1327                        __free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
1328        }
1329}
1330
1331static void free_unused_bufs(struct virtnet_info *vi)
1332{
1333        void *buf;
1334        int i;
1335
1336        for (i = 0; i < vi->max_queue_pairs; i++) {
1337                struct virtqueue *vq = vi->sq[i].vq;
1338                while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
1339                        dev_kfree_skb(buf);
1340        }
1341
1342        for (i = 0; i < vi->max_queue_pairs; i++) {
1343                struct virtqueue *vq = vi->rq[i].vq;
1344
1345                while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
1346                        if (vi->mergeable_rx_bufs || vi->big_packets)
1347                                give_pages(&vi->rq[i], buf);
1348                        else
1349                                dev_kfree_skb(buf);
1350                        --vi->rq[i].num;
1351                }
1352                BUG_ON(vi->rq[i].num != 0);
1353        }
1354}
1355
1356static void virtnet_del_vqs(struct virtnet_info *vi)
1357{
1358        struct virtio_device *vdev = vi->vdev;
1359
1360        virtnet_clean_affinity(vi, -1);
1361
1362        vdev->config->del_vqs(vdev);
1363
1364        virtnet_free_queues(vi);
1365}
1366
1367static int virtnet_find_vqs(struct virtnet_info *vi)
1368{
1369        vq_callback_t **callbacks;
1370        struct virtqueue **vqs;
1371        int ret = -ENOMEM;
1372        int i, total_vqs;
1373        const char **names;
1374
1375        /* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
1376         * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
1377         * possible control vq.
1378         */
1379        total_vqs = vi->max_queue_pairs * 2 +
1380                    virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
1381
1382        /* Allocate space for find_vqs parameters */
1383        vqs = kzalloc(total_vqs * sizeof(*vqs), GFP_KERNEL);
1384        if (!vqs)
1385                goto err_vq;
1386        callbacks = kmalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL);
1387        if (!callbacks)
1388                goto err_callback;
1389        names = kmalloc(total_vqs * sizeof(*names), GFP_KERNEL);
1390        if (!names)
1391                goto err_names;
1392
1393        /* Parameters for control virtqueue, if any */
1394        if (vi->has_cvq) {
1395                callbacks[total_vqs - 1] = NULL;
1396                names[total_vqs - 1] = "control";
1397        }
1398
1399        /* Allocate/initialize parameters for send/receive virtqueues */
1400        for (i = 0; i < vi->max_queue_pairs; i++) {
1401                callbacks[rxq2vq(i)] = skb_recv_done;
1402                callbacks[txq2vq(i)] = skb_xmit_done;
1403                sprintf(vi->rq[i].name, "input.%d", i);
1404                sprintf(vi->sq[i].name, "output.%d", i);
1405                names[rxq2vq(i)] = vi->rq[i].name;
1406                names[txq2vq(i)] = vi->sq[i].name;
1407        }
1408
1409        ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
1410                                         names);
1411        if (ret)
1412                goto err_find;
1413
1414        if (vi->has_cvq) {
1415                vi->cvq = vqs[total_vqs - 1];
1416                if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1417                        vi->dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
1418        }
1419
1420        for (i = 0; i < vi->max_queue_pairs; i++) {
1421                vi->rq[i].vq = vqs[rxq2vq(i)];
1422                vi->sq[i].vq = vqs[txq2vq(i)];
1423        }
1424
1425        kfree(names);
1426        kfree(callbacks);
1427        kfree(vqs);
1428
1429        return 0;
1430
1431err_find:
1432        kfree(names);
1433err_names:
1434        kfree(callbacks);
1435err_callback:
1436        kfree(vqs);
1437err_vq:
1438        return ret;
1439}
1440
1441static int virtnet_alloc_queues(struct virtnet_info *vi)
1442{
1443        int i;
1444
1445        vi->sq = kzalloc(sizeof(*vi->sq) * vi->max_queue_pairs, GFP_KERNEL);
1446        if (!vi->sq)
1447                goto err_sq;
1448        vi->rq = kzalloc(sizeof(*vi->rq) * vi->max_queue_pairs, GFP_KERNEL);
1449        if (!vi->rq)
1450                goto err_rq;
1451
1452        INIT_DELAYED_WORK(&vi->refill, refill_work);
1453        for (i = 0; i < vi->max_queue_pairs; i++) {
1454                vi->rq[i].pages = NULL;
1455                netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
1456                               napi_weight);
1457
1458                sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
1459                sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
1460        }
1461
1462        return 0;
1463
1464err_rq:
1465        kfree(vi->sq);
1466err_sq:
1467        return -ENOMEM;
1468}
1469
1470static int init_vqs(struct virtnet_info *vi)
1471{
1472        int ret;
1473
1474        /* Allocate send & receive queues */
1475        ret = virtnet_alloc_queues(vi);
1476        if (ret)
1477                goto err;
1478
1479        ret = virtnet_find_vqs(vi);
1480        if (ret)
1481                goto err_free;
1482
1483        get_online_cpus();
1484        virtnet_set_affinity(vi);
1485        put_online_cpus();
1486
1487        return 0;
1488
1489err_free:
1490        virtnet_free_queues(vi);
1491err:
1492        return ret;
1493}
1494
1495static int virtnet_probe(struct virtio_device *vdev)
1496{
1497        int i, err;
1498        struct net_device *dev;
1499        struct virtnet_info *vi;
1500        u16 max_queue_pairs;
1501
1502        /* Find if host supports multiqueue virtio_net device */
1503        err = virtio_config_val(vdev, VIRTIO_NET_F_MQ,
1504                                offsetof(struct virtio_net_config,
1505                                max_virtqueue_pairs), &max_queue_pairs);
1506
1507        /* We need at least 2 queue's */
1508        if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
1509            max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
1510            !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1511                max_queue_pairs = 1;
1512
1513        /* Allocate ourselves a network device with room for our info */
1514        dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
1515        if (!dev)
1516                return -ENOMEM;
1517
1518        /* Set up network device as normal. */
1519        dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE;
1520        dev->netdev_ops = &virtnet_netdev;
1521        dev->features = NETIF_F_HIGHDMA;
1522
1523        SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
1524        SET_NETDEV_DEV(dev, &vdev->dev);
1525
1526        /* Do we support "hardware" checksums? */
1527        if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
1528                /* This opens up the world of extra features. */
1529                dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1530                if (csum)
1531                        dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1532
1533                if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
1534                        dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
1535                                | NETIF_F_TSO_ECN | NETIF_F_TSO6;
1536                }
1537                /* Individual feature bits: what can host handle? */
1538                if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
1539                        dev->hw_features |= NETIF_F_TSO;
1540                if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
1541                        dev->hw_features |= NETIF_F_TSO6;
1542                if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
1543                        dev->hw_features |= NETIF_F_TSO_ECN;
1544                if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
1545                        dev->hw_features |= NETIF_F_UFO;
1546
1547                if (gso)
1548                        dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
1549                /* (!csum && gso) case will be fixed by register_netdev() */
1550        }
1551        if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_CSUM))
1552                dev->features |= NETIF_F_RXCSUM;
1553
1554        dev->vlan_features = dev->features;
1555
1556        /* Configuration may specify what MAC to use.  Otherwise random. */
1557        if (virtio_config_val_len(vdev, VIRTIO_NET_F_MAC,
1558                                  offsetof(struct virtio_net_config, mac),
1559                                  dev->dev_addr, dev->addr_len) < 0)
1560                eth_hw_addr_random(dev);
1561
1562        /* Set up our device-specific information */
1563        vi = netdev_priv(dev);
1564        vi->dev = dev;
1565        vi->vdev = vdev;
1566        vdev->priv = vi;
1567        vi->stats = alloc_percpu(struct virtnet_stats);
1568        err = -ENOMEM;
1569        if (vi->stats == NULL)
1570                goto free;
1571
1572        vi->vq_index = alloc_percpu(int);
1573        if (vi->vq_index == NULL)
1574                goto free_stats;
1575
1576        mutex_init(&vi->config_lock);
1577        vi->config_enable = true;
1578        INIT_WORK(&vi->config_work, virtnet_config_changed_work);
1579
1580        /* If we can receive ANY GSO packets, we must allocate large ones. */
1581        if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1582            virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
1583            virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
1584                vi->big_packets = true;
1585
1586        if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
1587                vi->mergeable_rx_bufs = true;
1588
1589        if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT))
1590                vi->any_header_sg = true;
1591
1592        if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1593                vi->has_cvq = true;
1594
1595        /* Use single tx/rx queue pair as default */
1596        vi->curr_queue_pairs = 1;
1597        vi->max_queue_pairs = max_queue_pairs;
1598
1599        /* Allocate/initialize the rx/tx queues, and invoke find_vqs */
1600        err = init_vqs(vi);
1601        if (err)
1602                goto free_index;
1603
1604        netif_set_real_num_tx_queues(dev, 1);
1605        netif_set_real_num_rx_queues(dev, 1);
1606
1607        err = register_netdev(dev);
1608        if (err) {
1609                pr_debug("virtio_net: registering device failed\n");
1610                goto free_vqs;
1611        }
1612
1613        /* Last of all, set up some receive buffers. */
1614        for (i = 0; i < vi->curr_queue_pairs; i++) {
1615                try_fill_recv(&vi->rq[i], GFP_KERNEL);
1616
1617                /* If we didn't even get one input buffer, we're useless. */
1618                if (vi->rq[i].num == 0) {
1619                        free_unused_bufs(vi);
1620                        err = -ENOMEM;
1621                        goto free_recv_bufs;
1622                }
1623        }
1624
1625        vi->nb.notifier_call = &virtnet_cpu_callback;
1626        err = register_hotcpu_notifier(&vi->nb);
1627        if (err) {
1628                pr_debug("virtio_net: registering cpu notifier failed\n");
1629                goto free_recv_bufs;
1630        }
1631
1632        /* Assume link up if device can't report link status,
1633           otherwise get link status from config. */
1634        if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1635                netif_carrier_off(dev);
1636                schedule_work(&vi->config_work);
1637        } else {
1638                vi->status = VIRTIO_NET_S_LINK_UP;
1639                netif_carrier_on(dev);
1640        }
1641
1642        pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
1643                 dev->name, max_queue_pairs);
1644
1645        return 0;
1646
1647free_recv_bufs:
1648        free_receive_bufs(vi);
1649        unregister_netdev(dev);
1650free_vqs:
1651        cancel_delayed_work_sync(&vi->refill);
1652        virtnet_del_vqs(vi);
1653free_index:
1654        free_percpu(vi->vq_index);
1655free_stats:
1656        free_percpu(vi->stats);
1657free:
1658        free_netdev(dev);
1659        return err;
1660}
1661
1662static void remove_vq_common(struct virtnet_info *vi)
1663{
1664        vi->vdev->config->reset(vi->vdev);
1665
1666        /* Free unused buffers in both send and recv, if any. */
1667        free_unused_bufs(vi);
1668
1669        free_receive_bufs(vi);
1670
1671        virtnet_del_vqs(vi);
1672}
1673
1674static void virtnet_remove(struct virtio_device *vdev)
1675{
1676        struct virtnet_info *vi = vdev->priv;
1677
1678        unregister_hotcpu_notifier(&vi->nb);
1679
1680        /* Prevent config work handler from accessing the device. */
1681        mutex_lock(&vi->config_lock);
1682        vi->config_enable = false;
1683        mutex_unlock(&vi->config_lock);
1684
1685        unregister_netdev(vi->dev);
1686
1687        remove_vq_common(vi);
1688
1689        flush_work(&vi->config_work);
1690
1691        free_percpu(vi->vq_index);
1692        free_percpu(vi->stats);
1693        free_netdev(vi->dev);
1694}
1695
1696#ifdef CONFIG_PM
1697static int virtnet_freeze(struct virtio_device *vdev)
1698{
1699        struct virtnet_info *vi = vdev->priv;
1700        int i;
1701
1702        /* Prevent config work handler from accessing the device */
1703        mutex_lock(&vi->config_lock);
1704        vi->config_enable = false;
1705        mutex_unlock(&vi->config_lock);
1706
1707        netif_device_detach(vi->dev);
1708        cancel_delayed_work_sync(&vi->refill);
1709
1710        if (netif_running(vi->dev))
1711                for (i = 0; i < vi->max_queue_pairs; i++) {
1712                        napi_disable(&vi->rq[i].napi);
1713                        netif_napi_del(&vi->rq[i].napi);
1714                }
1715
1716        remove_vq_common(vi);
1717
1718        flush_work(&vi->config_work);
1719
1720        return 0;
1721}
1722
1723static int virtnet_restore(struct virtio_device *vdev)
1724{
1725        struct virtnet_info *vi = vdev->priv;
1726        int err, i;
1727
1728        err = init_vqs(vi);
1729        if (err)
1730                return err;
1731
1732        if (netif_running(vi->dev))
1733                for (i = 0; i < vi->max_queue_pairs; i++)
1734                        virtnet_napi_enable(&vi->rq[i]);
1735
1736        netif_device_attach(vi->dev);
1737
1738        for (i = 0; i < vi->curr_queue_pairs; i++)
1739                if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
1740                        schedule_delayed_work(&vi->refill, 0);
1741
1742        mutex_lock(&vi->config_lock);
1743        vi->config_enable = true;
1744        mutex_unlock(&vi->config_lock);
1745
1746        rtnl_lock();
1747        virtnet_set_queues(vi, vi->curr_queue_pairs);
1748        rtnl_unlock();
1749
1750        return 0;
1751}
1752#endif
1753
1754static struct virtio_device_id id_table[] = {
1755        { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1756        { 0 },
1757};
1758
1759static unsigned int features[] = {
1760        VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1761        VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1762        VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
1763        VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1764        VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
1765        VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
1766        VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
1767        VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
1768        VIRTIO_NET_F_CTRL_MAC_ADDR,
1769        VIRTIO_F_ANY_LAYOUT,
1770};
1771
1772static struct virtio_driver virtio_net_driver = {
1773        .feature_table = features,
1774        .feature_table_size = ARRAY_SIZE(features),
1775        .driver.name =  KBUILD_MODNAME,
1776        .driver.owner = THIS_MODULE,
1777        .id_table =     id_table,
1778        .probe =        virtnet_probe,
1779        .remove =       virtnet_remove,
1780        .config_changed = virtnet_config_changed,
1781#ifdef CONFIG_PM
1782        .freeze =       virtnet_freeze,
1783        .restore =      virtnet_restore,
1784#endif
1785};
1786
1787module_virtio_driver(virtio_net_driver);
1788
1789MODULE_DEVICE_TABLE(virtio, id_table);
1790MODULE_DESCRIPTION("Virtio network driver");
1791MODULE_LICENSE("GPL");
1792
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