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