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 = 128;
  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_SEND_COMMAND_SG_MAX    2
  43#define VIRTNET_DRIVER_VERSION "1.0.0"
  44
  45struct virtnet_stats {
  46        struct u64_stats_sync tx_syncp;
  47        struct u64_stats_sync rx_syncp;
  48        u64 tx_bytes;
  49        u64 tx_packets;
  50
  51        u64 rx_bytes;
  52        u64 rx_packets;
  53};
  54
  55/* Internal representation of a send virtqueue */
  56struct send_queue {
  57        /* Virtqueue associated with this send _queue */
  58        struct virtqueue *vq;
  59
  60        /* TX: fragments + linear part + virtio header */
  61        struct scatterlist sg[MAX_SKB_FRAGS + 2];
  62
  63        /* Name of the send queue: output.$index */
  64        char name[40];
  65};
  66
  67/* Internal representation of a receive virtqueue */
  68struct receive_queue {
  69        /* Virtqueue associated with this receive_queue */
  70        struct virtqueue *vq;
  71
  72        struct napi_struct napi;
  73
  74        /* Number of input buffers, and max we've ever had. */
  75        unsigned int num, max;
  76
  77        /* Chain pages by the private ptr. */
  78        struct page *pages;
  79
  80        /* RX: fragments + linear part + virtio header */
  81        struct scatterlist sg[MAX_SKB_FRAGS + 2];
  82
  83        /* Name of this receive queue: input.$index */
  84        char name[40];
  85};
  86
  87struct virtnet_info {
  88        struct virtio_device *vdev;
  89        struct virtqueue *cvq;
  90        struct net_device *dev;
  91        struct send_queue *sq;
  92        struct receive_queue *rq;
  93        unsigned int status;
  94
  95        /* Max # of queue pairs supported by the device */
  96        u16 max_queue_pairs;
  97
  98        /* # of queue pairs currently used by the driver */
  99        u16 curr_queue_pairs;
 100
 101        /* I like... big packets and I cannot lie! */
 102        bool big_packets;
 103
 104        /* Host will merge rx buffers for big packets (shake it! shake it!) */
 105        bool mergeable_rx_bufs;
 106
 107        /* Has control virtqueue */
 108        bool has_cvq;
 109
 110        /* enable config space updates */
 111        bool config_enable;
 112
 113        /* Active statistics */
 114        struct virtnet_stats __percpu *stats;
 115
 116        /* Work struct for refilling if we run low on memory. */
 117        struct delayed_work refill;
 118
 119        /* Work struct for config space updates */
 120        struct work_struct config_work;
 121
 122        /* Lock for config space updates */
 123        struct mutex config_lock;
 124
 125        /* Does the affinity hint is set for virtqueues? */
 126        bool affinity_hint_set;
 127
 128        /* Per-cpu variable to show the mapping from CPU to virtqueue */
 129        int __percpu *vq_index;
 130
 131        /* CPU hot plug notifier */
 132        struct notifier_block nb;
 133};
 134
 135struct skb_vnet_hdr {
 136        union {
 137                struct virtio_net_hdr hdr;
 138                struct virtio_net_hdr_mrg_rxbuf mhdr;
 139        };
 140};
 141
 142struct padded_vnet_hdr {
 143        struct virtio_net_hdr hdr;
 144        /*
 145         * virtio_net_hdr should be in a separated sg buffer because of a
 146         * QEMU bug, and data sg buffer shares same page with this header sg.
 147         * This padding makes next sg 16 byte aligned after virtio_net_hdr.
 148         */
 149        char padding[6];
 150};
 151
 152/* Converting between virtqueue no. and kernel tx/rx queue no.
 153 * 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq
 154 */
 155static int vq2txq(struct virtqueue *vq)
 156{
 157        return (virtqueue_get_queue_index(vq) - 1) / 2;
 158}
 159
 160static int txq2vq(int txq)
 161{
 162        return txq * 2 + 1;
 163}
 164
 165static int vq2rxq(struct virtqueue *vq)
 166{
 167        return virtqueue_get_queue_index(vq) / 2;
 168}
 169
 170static int rxq2vq(int rxq)
 171{
 172        return rxq * 2;
 173}
 174
 175static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
 176{
 177        return (struct skb_vnet_hdr *)skb->cb;
 178}
 179
 180/*
 181 * private is used to chain pages for big packets, put the whole
 182 * most recent used list in the beginning for reuse
 183 */
 184static void give_pages(struct receive_queue *rq, struct page *page)
 185{
 186        struct page *end;
 187
 188        /* Find end of list, sew whole thing into vi->rq.pages. */
 189        for (end = page; end->private; end = (struct page *)end->private);
 190        end->private = (unsigned long)rq->pages;
 191        rq->pages = page;
 192}
 193
 194static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
 195{
 196        struct page *p = rq->pages;
 197
 198        if (p) {
 199                rq->pages = (struct page *)p->private;
 200                /* clear private here, it is used to chain pages */
 201                p->private = 0;
 202        } else
 203                p = alloc_page(gfp_mask);
 204        return p;
 205}
 206
 207static void skb_xmit_done(struct virtqueue *vq)
 208{
 209        struct virtnet_info *vi = vq->vdev->priv;
 210
 211        /* Suppress further interrupts. */
 212        virtqueue_disable_cb(vq);
 213
 214        /* We were probably waiting for more output buffers. */
 215        netif_wake_subqueue(vi->dev, vq2txq(vq));
 216}
 217
 218static void set_skb_frag(struct sk_buff *skb, struct page *page,
 219                         unsigned int offset, unsigned int *len)
 220{
 221        int size = min((unsigned)PAGE_SIZE - offset, *len);
 222        int i = skb_shinfo(skb)->nr_frags;
 223
 224        __skb_fill_page_desc(skb, i, page, offset, size);
 225
 226        skb->data_len += size;
 227        skb->len += size;
 228        skb->truesize += PAGE_SIZE;
 229        skb_shinfo(skb)->nr_frags++;
 230        *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_buf(rq->vq, rq->sg, 0, 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_buf(rq->vq, rq->sg, 0, 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_buf(rq->vq, rq->sg, 0, 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->max_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                /* Make sure we have some buffers: if oom use wq. */
 641                if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
 642                        schedule_delayed_work(&vi->refill, 0);
 643                virtnet_napi_enable(&vi->rq[i]);
 644        }
 645
 646        return 0;
 647}
 648
 649static void free_old_xmit_skbs(struct send_queue *sq)
 650{
 651        struct sk_buff *skb;
 652        unsigned int len;
 653        struct virtnet_info *vi = sq->vq->vdev->priv;
 654        struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
 655
 656        while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {
 657                pr_debug("Sent skb %p\n", skb);
 658
 659                u64_stats_update_begin(&stats->tx_syncp);
 660                stats->tx_bytes += skb->len;
 661                stats->tx_packets++;
 662                u64_stats_update_end(&stats->tx_syncp);
 663
 664                dev_kfree_skb_any(skb);
 665        }
 666}
 667
 668static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
 669{
 670        struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 671        const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 672        struct virtnet_info *vi = sq->vq->vdev->priv;
 673        unsigned num_sg;
 674
 675        pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
 676
 677        if (skb->ip_summed == CHECKSUM_PARTIAL) {
 678                hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 679                hdr->hdr.csum_start = skb_checksum_start_offset(skb);
 680                hdr->hdr.csum_offset = skb->csum_offset;
 681        } else {
 682                hdr->hdr.flags = 0;
 683                hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
 684        }
 685
 686        if (skb_is_gso(skb)) {
 687                hdr->hdr.hdr_len = skb_headlen(skb);
 688                hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
 689                if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 690                        hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 691                else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 692                        hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 693                else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 694                        hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 695                else
 696                        BUG();
 697                if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
 698                        hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 699        } else {
 700                hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 701                hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
 702        }
 703
 704        hdr->mhdr.num_buffers = 0;
 705
 706        /* Encode metadata header at front. */
 707        if (vi->mergeable_rx_bufs)
 708                sg_set_buf(sq->sg, &hdr->mhdr, sizeof hdr->mhdr);
 709        else
 710                sg_set_buf(sq->sg, &hdr->hdr, sizeof hdr->hdr);
 711
 712        num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
 713        return virtqueue_add_buf(sq->vq, sq->sg, num_sg,
 714                                 0, 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
 763static int virtnet_set_mac_address(struct net_device *dev, void *p)
 764{
 765        struct virtnet_info *vi = netdev_priv(dev);
 766        struct virtio_device *vdev = vi->vdev;
 767        int ret;
 768
 769        ret = eth_mac_addr(dev, p);
 770        if (ret)
 771                return ret;
 772
 773        if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
 774                vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
 775                                  dev->dev_addr, dev->addr_len);
 776
 777        return 0;
 778}
 779
 780static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
 781                                               struct rtnl_link_stats64 *tot)
 782{
 783        struct virtnet_info *vi = netdev_priv(dev);
 784        int cpu;
 785        unsigned int start;
 786
 787        for_each_possible_cpu(cpu) {
 788                struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
 789                u64 tpackets, tbytes, rpackets, rbytes;
 790
 791                do {
 792                        start = u64_stats_fetch_begin_bh(&stats->tx_syncp);
 793                        tpackets = stats->tx_packets;
 794                        tbytes   = stats->tx_bytes;
 795                } while (u64_stats_fetch_retry_bh(&stats->tx_syncp, start));
 796
 797                do {
 798                        start = u64_stats_fetch_begin_bh(&stats->rx_syncp);
 799                        rpackets = stats->rx_packets;
 800                        rbytes   = stats->rx_bytes;
 801                } while (u64_stats_fetch_retry_bh(&stats->rx_syncp, start));
 802
 803                tot->rx_packets += rpackets;
 804                tot->tx_packets += tpackets;
 805                tot->rx_bytes   += rbytes;
 806                tot->tx_bytes   += tbytes;
 807        }
 808
 809        tot->tx_dropped = dev->stats.tx_dropped;
 810        tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
 811        tot->rx_dropped = dev->stats.rx_dropped;
 812        tot->rx_length_errors = dev->stats.rx_length_errors;
 813        tot->rx_frame_errors = dev->stats.rx_frame_errors;
 814
 815        return tot;
 816}
 817
 818#ifdef CONFIG_NET_POLL_CONTROLLER
 819static void virtnet_netpoll(struct net_device *dev)
 820{
 821        struct virtnet_info *vi = netdev_priv(dev);
 822        int i;
 823
 824        for (i = 0; i < vi->curr_queue_pairs; i++)
 825                napi_schedule(&vi->rq[i].napi);
 826}
 827#endif
 828
 829/*
 830 * Send command via the control virtqueue and check status.  Commands
 831 * supported by the hypervisor, as indicated by feature bits, should
 832 * never fail unless improperly formated.
 833 */
 834static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
 835                                 struct scatterlist *data, int out, int in)
 836{
 837        struct scatterlist *s, sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
 838        struct virtio_net_ctrl_hdr ctrl;
 839        virtio_net_ctrl_ack status = ~0;
 840        unsigned int tmp;
 841        int i;
 842
 843        /* Caller should know better */
 844        BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ||
 845                (out + in > VIRTNET_SEND_COMMAND_SG_MAX));
 846
 847        out++; /* Add header */
 848        in++; /* Add return status */
 849
 850        ctrl.class = class;
 851        ctrl.cmd = cmd;
 852
 853        sg_init_table(sg, out + in);
 854
 855        sg_set_buf(&sg[0], &ctrl, sizeof(ctrl));
 856        for_each_sg(data, s, out + in - 2, i)
 857                sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
 858        sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
 859
 860        BUG_ON(virtqueue_add_buf(vi->cvq, sg, out, in, vi, GFP_ATOMIC) < 0);
 861
 862        virtqueue_kick(vi->cvq);
 863
 864        /*
 865         * Spin for a response, the kick causes an ioport write, trapping
 866         * into the hypervisor, so the request should be handled immediately.
 867         */
 868        while (!virtqueue_get_buf(vi->cvq, &tmp))
 869                cpu_relax();
 870
 871        return status == VIRTIO_NET_OK;
 872}
 873
 874static void virtnet_ack_link_announce(struct virtnet_info *vi)
 875{
 876        rtnl_lock();
 877        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
 878                                  VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL,
 879                                  0, 0))
 880                dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
 881        rtnl_unlock();
 882}
 883
 884static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
 885{
 886        struct scatterlist sg;
 887        struct virtio_net_ctrl_mq s;
 888        struct net_device *dev = vi->dev;
 889
 890        if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
 891                return 0;
 892
 893        s.virtqueue_pairs = queue_pairs;
 894        sg_init_one(&sg, &s, sizeof(s));
 895
 896        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
 897                                  VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg, 1, 0)){
 898                dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
 899                         queue_pairs);
 900                return -EINVAL;
 901        } else
 902                vi->curr_queue_pairs = queue_pairs;
 903
 904        return 0;
 905}
 906
 907static int virtnet_close(struct net_device *dev)
 908{
 909        struct virtnet_info *vi = netdev_priv(dev);
 910        int i;
 911
 912        /* Make sure refill_work doesn't re-enable napi! */
 913        cancel_delayed_work_sync(&vi->refill);
 914
 915        for (i = 0; i < vi->max_queue_pairs; i++)
 916                napi_disable(&vi->rq[i].napi);
 917
 918        return 0;
 919}
 920
 921static void virtnet_set_rx_mode(struct net_device *dev)
 922{
 923        struct virtnet_info *vi = netdev_priv(dev);
 924        struct scatterlist sg[2];
 925        u8 promisc, allmulti;
 926        struct virtio_net_ctrl_mac *mac_data;
 927        struct netdev_hw_addr *ha;
 928        int uc_count;
 929        int mc_count;
 930        void *buf;
 931        int i;
 932
 933        /* We can't dynamicaly set ndo_set_rx_mode, so return gracefully */
 934        if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
 935                return;
 936
 937        promisc = ((dev->flags & IFF_PROMISC) != 0);
 938        allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
 939
 940        sg_init_one(sg, &promisc, sizeof(promisc));
 941
 942        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 943                                  VIRTIO_NET_CTRL_RX_PROMISC,
 944                                  sg, 1, 0))
 945                dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
 946                         promisc ? "en" : "dis");
 947
 948        sg_init_one(sg, &allmulti, sizeof(allmulti));
 949
 950        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 951                                  VIRTIO_NET_CTRL_RX_ALLMULTI,
 952                                  sg, 1, 0))
 953                dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
 954                         allmulti ? "en" : "dis");
 955
 956        uc_count = netdev_uc_count(dev);
 957        mc_count = netdev_mc_count(dev);
 958        /* MAC filter - use one buffer for both lists */
 959        buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
 960                      (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
 961        mac_data = buf;
 962        if (!buf) {
 963                dev_warn(&dev->dev, "No memory for MAC address buffer\n");
 964                return;
 965        }
 966
 967        sg_init_table(sg, 2);
 968
 969        /* Store the unicast list and count in the front of the buffer */
 970        mac_data->entries = uc_count;
 971        i = 0;
 972        netdev_for_each_uc_addr(ha, dev)
 973                memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 974
 975        sg_set_buf(&sg[0], mac_data,
 976                   sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
 977
 978        /* multicast list and count fill the end */
 979        mac_data = (void *)&mac_data->macs[uc_count][0];
 980
 981        mac_data->entries = mc_count;
 982        i = 0;
 983        netdev_for_each_mc_addr(ha, dev)
 984                memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 985
 986        sg_set_buf(&sg[1], mac_data,
 987                   sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
 988
 989        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
 990                                  VIRTIO_NET_CTRL_MAC_TABLE_SET,
 991                                  sg, 2, 0))
 992                dev_warn(&dev->dev, "Failed to set MAC fitler table.\n");
 993
 994        kfree(buf);
 995}
 996
 997static int virtnet_vlan_rx_add_vid(struct net_device *dev, u16 vid)
 998{
 999        struct virtnet_info *vi = netdev_priv(dev);
1000        struct scatterlist sg;
1001
1002        sg_init_one(&sg, &vid, sizeof(vid));
1003
1004        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1005                                  VIRTIO_NET_CTRL_VLAN_ADD, &sg, 1, 0))
1006                dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
1007        return 0;
1008}
1009
1010static int virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
1011{
1012        struct virtnet_info *vi = netdev_priv(dev);
1013        struct scatterlist sg;
1014
1015        sg_init_one(&sg, &vid, sizeof(vid));
1016
1017        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1018                                  VIRTIO_NET_CTRL_VLAN_DEL, &sg, 1, 0))
1019                dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
1020        return 0;
1021}
1022
1023static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
1024{
1025        int i;
1026        int cpu;
1027
1028        if (vi->affinity_hint_set) {
1029                for (i = 0; i < vi->max_queue_pairs; i++) {
1030                        virtqueue_set_affinity(vi->rq[i].vq, -1);
1031                        virtqueue_set_affinity(vi->sq[i].vq, -1);
1032                }
1033
1034                vi->affinity_hint_set = false;
1035        }
1036
1037        i = 0;
1038        for_each_online_cpu(cpu) {
1039                if (cpu == hcpu) {
1040                        *per_cpu_ptr(vi->vq_index, cpu) = -1;
1041                } else {
1042                        *per_cpu_ptr(vi->vq_index, cpu) =
1043                                ++i % vi->curr_queue_pairs;
1044                }
1045        }
1046}
1047
1048static void virtnet_set_affinity(struct virtnet_info *vi)
1049{
1050        int i;
1051        int cpu;
1052
1053        /* In multiqueue mode, when the number of cpu is equal to the number of
1054         * queue pairs, we let the queue pairs to be private to one cpu by
1055         * setting the affinity hint to eliminate the contention.
1056         */
1057        if (vi->curr_queue_pairs == 1 ||
1058            vi->max_queue_pairs != num_online_cpus()) {
1059                virtnet_clean_affinity(vi, -1);
1060                return;
1061        }
1062
1063        i = 0;
1064        for_each_online_cpu(cpu) {
1065                virtqueue_set_affinity(vi->rq[i].vq, cpu);
1066                virtqueue_set_affinity(vi->sq[i].vq, cpu);
1067                *per_cpu_ptr(vi->vq_index, cpu) = i;
1068                i++;
1069        }
1070
1071        vi->affinity_hint_set = true;
1072}
1073
1074static int virtnet_cpu_callback(struct notifier_block *nfb,
1075                                unsigned long action, void *hcpu)
1076{
1077        struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
1078
1079        switch(action & ~CPU_TASKS_FROZEN) {
1080        case CPU_ONLINE:
1081        case CPU_DOWN_FAILED:
1082        case CPU_DEAD:
1083                virtnet_set_affinity(vi);
1084                break;
1085        case CPU_DOWN_PREPARE:
1086                virtnet_clean_affinity(vi, (long)hcpu);
1087                break;
1088        default:
1089                break;
1090        }
1091        return NOTIFY_OK;
1092}
1093
1094static void virtnet_get_ringparam(struct net_device *dev,
1095                                struct ethtool_ringparam *ring)
1096{
1097        struct virtnet_info *vi = netdev_priv(dev);
1098
1099        ring->rx_max_pending = virtqueue_get_vring_size(vi->rq[0].vq);
1100        ring->tx_max_pending = virtqueue_get_vring_size(vi->sq[0].vq);
1101        ring->rx_pending = ring->rx_max_pending;
1102        ring->tx_pending = ring->tx_max_pending;
1103}
1104
1105
1106static void virtnet_get_drvinfo(struct net_device *dev,
1107                                struct ethtool_drvinfo *info)
1108{
1109        struct virtnet_info *vi = netdev_priv(dev);
1110        struct virtio_device *vdev = vi->vdev;
1111
1112        strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
1113        strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
1114        strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
1115
1116}
1117
1118/* TODO: Eliminate OOO packets during switching */
1119static int virtnet_set_channels(struct net_device *dev,
1120                                struct ethtool_channels *channels)
1121{
1122        struct virtnet_info *vi = netdev_priv(dev);
1123        u16 queue_pairs = channels->combined_count;
1124        int err;
1125
1126        /* We don't support separate rx/tx channels.
1127         * We don't allow setting 'other' channels.
1128         */
1129        if (channels->rx_count || channels->tx_count || channels->other_count)
1130                return -EINVAL;
1131
1132        if (queue_pairs > vi->max_queue_pairs)
1133                return -EINVAL;
1134
1135        get_online_cpus();
1136        err = virtnet_set_queues(vi, queue_pairs);
1137        if (!err) {
1138                netif_set_real_num_tx_queues(dev, queue_pairs);
1139                netif_set_real_num_rx_queues(dev, queue_pairs);
1140
1141                virtnet_set_affinity(vi);
1142        }
1143        put_online_cpus();
1144
1145        return err;
1146}
1147
1148static void virtnet_get_channels(struct net_device *dev,
1149                                 struct ethtool_channels *channels)
1150{
1151        struct virtnet_info *vi = netdev_priv(dev);
1152
1153        channels->combined_count = vi->curr_queue_pairs;
1154        channels->max_combined = vi->max_queue_pairs;
1155        channels->max_other = 0;
1156        channels->rx_count = 0;
1157        channels->tx_count = 0;
1158        channels->other_count = 0;
1159}
1160
1161static const struct ethtool_ops virtnet_ethtool_ops = {
1162        .get_drvinfo = virtnet_get_drvinfo,
1163        .get_link = ethtool_op_get_link,
1164        .get_ringparam = virtnet_get_ringparam,
1165        .set_channels = virtnet_set_channels,
1166        .get_channels = virtnet_get_channels,
1167};
1168
1169#define MIN_MTU 68
1170#define MAX_MTU 65535
1171
1172static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
1173{
1174        if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
1175                return -EINVAL;
1176        dev->mtu = new_mtu;
1177        return 0;
1178}
1179
1180/* To avoid contending a lock hold by a vcpu who would exit to host, select the
1181 * txq based on the processor id.
1182 */
1183static u16 virtnet_select_queue(struct net_device *dev, struct sk_buff *skb)
1184{
1185        int txq;
1186        struct virtnet_info *vi = netdev_priv(dev);
1187
1188        if (skb_rx_queue_recorded(skb)) {
1189                txq = skb_get_rx_queue(skb);
1190        } else {
1191                txq = *__this_cpu_ptr(vi->vq_index);
1192                if (txq == -1)
1193                        txq = 0;
1194        }
1195
1196        while (unlikely(txq >= dev->real_num_tx_queues))
1197                txq -= dev->real_num_tx_queues;
1198
1199        return txq;
1200}
1201
1202static const struct net_device_ops virtnet_netdev = {
1203        .ndo_open            = virtnet_open,
1204        .ndo_stop            = virtnet_close,
1205        .ndo_start_xmit      = start_xmit,
1206        .ndo_validate_addr   = eth_validate_addr,
1207        .ndo_set_mac_address = virtnet_set_mac_address,
1208        .ndo_set_rx_mode     = virtnet_set_rx_mode,
1209        .ndo_change_mtu      = virtnet_change_mtu,
1210        .ndo_get_stats64     = virtnet_stats,
1211        .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
1212        .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
1213        .ndo_select_queue     = virtnet_select_queue,
1214#ifdef CONFIG_NET_POLL_CONTROLLER
1215        .ndo_poll_controller = virtnet_netpoll,
1216#endif
1217};
1218
1219static void virtnet_config_changed_work(struct work_struct *work)
1220{
1221        struct virtnet_info *vi =
1222                container_of(work, struct virtnet_info, config_work);
1223        u16 v;
1224
1225        mutex_lock(&vi->config_lock);
1226        if (!vi->config_enable)
1227                goto done;
1228
1229        if (virtio_config_val(vi->vdev, VIRTIO_NET_F_STATUS,
1230                              offsetof(struct virtio_net_config, status),
1231                              &v) < 0)
1232                goto done;
1233
1234        if (v & VIRTIO_NET_S_ANNOUNCE) {
1235                netdev_notify_peers(vi->dev);
1236                virtnet_ack_link_announce(vi);
1237        }
1238
1239        /* Ignore unknown (future) status bits */
1240        v &= VIRTIO_NET_S_LINK_UP;
1241
1242        if (vi->status == v)
1243                goto done;
1244
1245        vi->status = v;
1246
1247        if (vi->status & VIRTIO_NET_S_LINK_UP) {
1248                netif_carrier_on(vi->dev);
1249                netif_tx_wake_all_queues(vi->dev);
1250        } else {
1251                netif_carrier_off(vi->dev);
1252                netif_tx_stop_all_queues(vi->dev);
1253        }
1254done:
1255        mutex_unlock(&vi->config_lock);
1256}
1257
1258static void virtnet_config_changed(struct virtio_device *vdev)
1259{
1260        struct virtnet_info *vi = vdev->priv;
1261
1262        schedule_work(&vi->config_work);
1263}
1264
1265static void virtnet_free_queues(struct virtnet_info *vi)
1266{
1267        kfree(vi->rq);
1268        kfree(vi->sq);
1269}
1270
1271static void free_receive_bufs(struct virtnet_info *vi)
1272{
1273        int i;
1274
1275        for (i = 0; i < vi->max_queue_pairs; i++) {
1276                while (vi->rq[i].pages)
1277                        __free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
1278        }
1279}
1280
1281static void free_unused_bufs(struct virtnet_info *vi)
1282{
1283        void *buf;
1284        int i;
1285
1286        for (i = 0; i < vi->max_queue_pairs; i++) {
1287                struct virtqueue *vq = vi->sq[i].vq;
1288                while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
1289                        dev_kfree_skb(buf);
1290        }
1291
1292        for (i = 0; i < vi->max_queue_pairs; i++) {
1293                struct virtqueue *vq = vi->rq[i].vq;
1294
1295                while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
1296                        if (vi->mergeable_rx_bufs || vi->big_packets)
1297                                give_pages(&vi->rq[i], buf);
1298                        else
1299                                dev_kfree_skb(buf);
1300                        --vi->rq[i].num;
1301                }
1302                BUG_ON(vi->rq[i].num != 0);
1303        }
1304}
1305
1306static void virtnet_del_vqs(struct virtnet_info *vi)
1307{
1308        struct virtio_device *vdev = vi->vdev;
1309
1310        virtnet_clean_affinity(vi, -1);
1311
1312        vdev->config->del_vqs(vdev);
1313
1314        virtnet_free_queues(vi);
1315}
1316
1317static int virtnet_find_vqs(struct virtnet_info *vi)
1318{
1319        vq_callback_t **callbacks;
1320        struct virtqueue **vqs;
1321        int ret = -ENOMEM;
1322        int i, total_vqs;
1323        const char **names;
1324
1325        /* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
1326         * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
1327         * possible control vq.
1328         */
1329        total_vqs = vi->max_queue_pairs * 2 +
1330                    virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
1331
1332        /* Allocate space for find_vqs parameters */
1333        vqs = kzalloc(total_vqs * sizeof(*vqs), GFP_KERNEL);
1334        if (!vqs)
1335                goto err_vq;
1336        callbacks = kmalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL);
1337        if (!callbacks)
1338                goto err_callback;
1339        names = kmalloc(total_vqs * sizeof(*names), GFP_KERNEL);
1340        if (!names)
1341                goto err_names;
1342
1343        /* Parameters for control virtqueue, if any */
1344        if (vi->has_cvq) {
1345                callbacks[total_vqs - 1] = NULL;
1346                names[total_vqs - 1] = "control";
1347        }
1348
1349        /* Allocate/initialize parameters for send/receive virtqueues */
1350        for (i = 0; i < vi->max_queue_pairs; i++) {
1351                callbacks[rxq2vq(i)] = skb_recv_done;
1352                callbacks[txq2vq(i)] = skb_xmit_done;
1353                sprintf(vi->rq[i].name, "input.%d", i);
1354                sprintf(vi->sq[i].name, "output.%d", i);
1355                names[rxq2vq(i)] = vi->rq[i].name;
1356                names[txq2vq(i)] = vi->sq[i].name;
1357        }
1358
1359        ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
1360                                         names);
1361        if (ret)
1362                goto err_find;
1363
1364        if (vi->has_cvq) {
1365                vi->cvq = vqs[total_vqs - 1];
1366                if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1367                        vi->dev->features |= NETIF_F_HW_VLAN_FILTER;
1368        }
1369
1370        for (i = 0; i < vi->max_queue_pairs; i++) {
1371                vi->rq[i].vq = vqs[rxq2vq(i)];
1372                vi->sq[i].vq = vqs[txq2vq(i)];
1373        }
1374
1375        kfree(names);
1376        kfree(callbacks);
1377        kfree(vqs);
1378
1379        return 0;
1380
1381err_find:
1382        kfree(names);
1383err_names:
1384        kfree(callbacks);
1385err_callback:
1386        kfree(vqs);
1387err_vq:
1388        return ret;
1389}
1390
1391static int virtnet_alloc_queues(struct virtnet_info *vi)
1392{
1393        int i;
1394
1395        vi->sq = kzalloc(sizeof(*vi->sq) * vi->max_queue_pairs, GFP_KERNEL);
1396        if (!vi->sq)
1397                goto err_sq;
1398        vi->rq = kzalloc(sizeof(*vi->rq) * vi->max_queue_pairs, GFP_KERNEL);
1399        if (!vi->rq)
1400                goto err_rq;
1401
1402        INIT_DELAYED_WORK(&vi->refill, refill_work);
1403        for (i = 0; i < vi->max_queue_pairs; i++) {
1404                vi->rq[i].pages = NULL;
1405                netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
1406                               napi_weight);
1407
1408                sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
1409                sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
1410        }
1411
1412        return 0;
1413
1414err_rq:
1415        kfree(vi->sq);
1416err_sq:
1417        return -ENOMEM;
1418}
1419
1420static int init_vqs(struct virtnet_info *vi)
1421{
1422        int ret;
1423
1424        /* Allocate send & receive queues */
1425        ret = virtnet_alloc_queues(vi);
1426        if (ret)
1427                goto err;
1428
1429        ret = virtnet_find_vqs(vi);
1430        if (ret)
1431                goto err_free;
1432
1433        get_online_cpus();
1434        virtnet_set_affinity(vi);
1435        put_online_cpus();
1436
1437        return 0;
1438
1439err_free:
1440        virtnet_free_queues(vi);
1441err:
1442        return ret;
1443}
1444
1445static int virtnet_probe(struct virtio_device *vdev)
1446{
1447        int i, err;
1448        struct net_device *dev;
1449        struct virtnet_info *vi;
1450        u16 max_queue_pairs;
1451
1452        /* Find if host supports multiqueue virtio_net device */
1453        err = virtio_config_val(vdev, VIRTIO_NET_F_MQ,
1454                                offsetof(struct virtio_net_config,
1455                                max_virtqueue_pairs), &max_queue_pairs);
1456
1457        /* We need at least 2 queue's */
1458        if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
1459            max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
1460            !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1461                max_queue_pairs = 1;
1462
1463        /* Allocate ourselves a network device with room for our info */
1464        dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
1465        if (!dev)
1466                return -ENOMEM;
1467
1468        /* Set up network device as normal. */
1469        dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE;
1470        dev->netdev_ops = &virtnet_netdev;
1471        dev->features = NETIF_F_HIGHDMA;
1472
1473        SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
1474        SET_NETDEV_DEV(dev, &vdev->dev);
1475
1476        /* Do we support "hardware" checksums? */
1477        if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
1478                /* This opens up the world of extra features. */
1479                dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1480                if (csum)
1481                        dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1482
1483                if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
1484                        dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
1485                                | NETIF_F_TSO_ECN | NETIF_F_TSO6;
1486                }
1487                /* Individual feature bits: what can host handle? */
1488                if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
1489                        dev->hw_features |= NETIF_F_TSO;
1490                if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
1491                        dev->hw_features |= NETIF_F_TSO6;
1492                if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
1493                        dev->hw_features |= NETIF_F_TSO_ECN;
1494                if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
1495                        dev->hw_features |= NETIF_F_UFO;
1496
1497                if (gso)
1498                        dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
1499                /* (!csum && gso) case will be fixed by register_netdev() */
1500        }
1501
1502        /* Configuration may specify what MAC to use.  Otherwise random. */
1503        if (virtio_config_val_len(vdev, VIRTIO_NET_F_MAC,
1504                                  offsetof(struct virtio_net_config, mac),
1505                                  dev->dev_addr, dev->addr_len) < 0)
1506                eth_hw_addr_random(dev);
1507
1508        /* Set up our device-specific information */
1509        vi = netdev_priv(dev);
1510        vi->dev = dev;
1511        vi->vdev = vdev;
1512        vdev->priv = vi;
1513        vi->stats = alloc_percpu(struct virtnet_stats);
1514        err = -ENOMEM;
1515        if (vi->stats == NULL)
1516                goto free;
1517
1518        vi->vq_index = alloc_percpu(int);
1519        if (vi->vq_index == NULL)
1520                goto free_stats;
1521
1522        mutex_init(&vi->config_lock);
1523        vi->config_enable = true;
1524        INIT_WORK(&vi->config_work, virtnet_config_changed_work);
1525
1526        /* If we can receive ANY GSO packets, we must allocate large ones. */
1527        if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1528            virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
1529            virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
1530                vi->big_packets = true;
1531
1532        if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
1533                vi->mergeable_rx_bufs = true;
1534
1535        if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1536                vi->has_cvq = true;
1537
1538        /* Use single tx/rx queue pair as default */
1539        vi->curr_queue_pairs = 1;
1540        vi->max_queue_pairs = max_queue_pairs;
1541
1542        /* Allocate/initialize the rx/tx queues, and invoke find_vqs */
1543        err = init_vqs(vi);
1544        if (err)
1545                goto free_index;
1546
1547        netif_set_real_num_tx_queues(dev, 1);
1548        netif_set_real_num_rx_queues(dev, 1);
1549
1550        err = register_netdev(dev);
1551        if (err) {
1552                pr_debug("virtio_net: registering device failed\n");
1553                goto free_vqs;
1554        }
1555
1556        /* Last of all, set up some receive buffers. */
1557        for (i = 0; i < vi->max_queue_pairs; i++) {
1558                try_fill_recv(&vi->rq[i], GFP_KERNEL);
1559
1560                /* If we didn't even get one input buffer, we're useless. */
1561                if (vi->rq[i].num == 0) {
1562                        free_unused_bufs(vi);
1563                        err = -ENOMEM;
1564                        goto free_recv_bufs;
1565                }
1566        }
1567
1568        vi->nb.notifier_call = &virtnet_cpu_callback;
1569        err = register_hotcpu_notifier(&vi->nb);
1570        if (err) {
1571                pr_debug("virtio_net: registering cpu notifier failed\n");
1572                goto free_recv_bufs;
1573        }
1574
1575        /* Assume link up if device can't report link status,
1576           otherwise get link status from config. */
1577        if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1578                netif_carrier_off(dev);
1579                schedule_work(&vi->config_work);
1580        } else {
1581                vi->status = VIRTIO_NET_S_LINK_UP;
1582                netif_carrier_on(dev);
1583        }
1584
1585        pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
1586                 dev->name, max_queue_pairs);
1587
1588        return 0;
1589
1590free_recv_bufs:
1591        free_receive_bufs(vi);
1592        unregister_netdev(dev);
1593free_vqs:
1594        cancel_delayed_work_sync(&vi->refill);
1595        virtnet_del_vqs(vi);
1596free_index:
1597        free_percpu(vi->vq_index);
1598free_stats:
1599        free_percpu(vi->stats);
1600free:
1601        free_netdev(dev);
1602        return err;
1603}
1604
1605static void remove_vq_common(struct virtnet_info *vi)
1606{
1607        vi->vdev->config->reset(vi->vdev);
1608
1609        /* Free unused buffers in both send and recv, if any. */
1610        free_unused_bufs(vi);
1611
1612        free_receive_bufs(vi);
1613
1614        virtnet_del_vqs(vi);
1615}
1616
1617static void virtnet_remove(struct virtio_device *vdev)
1618{
1619        struct virtnet_info *vi = vdev->priv;
1620
1621        unregister_hotcpu_notifier(&vi->nb);
1622
1623        /* Prevent config work handler from accessing the device. */
1624        mutex_lock(&vi->config_lock);
1625        vi->config_enable = false;
1626        mutex_unlock(&vi->config_lock);
1627
1628        unregister_netdev(vi->dev);
1629
1630        remove_vq_common(vi);
1631
1632        flush_work(&vi->config_work);
1633
1634        free_percpu(vi->vq_index);
1635        free_percpu(vi->stats);
1636        free_netdev(vi->dev);
1637}
1638
1639#ifdef CONFIG_PM
1640static int virtnet_freeze(struct virtio_device *vdev)
1641{
1642        struct virtnet_info *vi = vdev->priv;
1643        int i;
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        netif_device_detach(vi->dev);
1651        cancel_delayed_work_sync(&vi->refill);
1652
1653        if (netif_running(vi->dev))
1654                for (i = 0; i < vi->max_queue_pairs; i++) {
1655                        napi_disable(&vi->rq[i].napi);
1656                        netif_napi_del(&vi->rq[i].napi);
1657                }
1658
1659        remove_vq_common(vi);
1660
1661        flush_work(&vi->config_work);
1662
1663        return 0;
1664}
1665
1666static int virtnet_restore(struct virtio_device *vdev)
1667{
1668        struct virtnet_info *vi = vdev->priv;
1669        int err, i;
1670
1671        err = init_vqs(vi);
1672        if (err)
1673                return err;
1674
1675        if (netif_running(vi->dev))
1676                for (i = 0; i < vi->max_queue_pairs; i++)
1677                        virtnet_napi_enable(&vi->rq[i]);
1678
1679        netif_device_attach(vi->dev);
1680
1681        for (i = 0; i < vi->max_queue_pairs; i++)
1682                if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
1683                        schedule_delayed_work(&vi->refill, 0);
1684
1685        mutex_lock(&vi->config_lock);
1686        vi->config_enable = true;
1687        mutex_unlock(&vi->config_lock);
1688
1689        virtnet_set_queues(vi, vi->curr_queue_pairs);
1690
1691        return 0;
1692}
1693#endif
1694
1695static struct virtio_device_id id_table[] = {
1696        { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1697        { 0 },
1698};
1699
1700static unsigned int features[] = {
1701        VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1702        VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1703        VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
1704        VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1705        VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
1706        VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
1707        VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
1708        VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
1709};
1710
1711static struct virtio_driver virtio_net_driver = {
1712        .feature_table = features,
1713        .feature_table_size = ARRAY_SIZE(features),
1714        .driver.name =  KBUILD_MODNAME,
1715        .driver.owner = THIS_MODULE,
1716        .id_table =     id_table,
1717        .probe =        virtnet_probe,
1718        .remove =       virtnet_remove,
1719        .config_changed = virtnet_config_changed,
1720#ifdef CONFIG_PM
1721        .freeze =       virtnet_freeze,
1722        .restore =      virtnet_restore,
1723#endif
1724};
1725
1726static int __init init(void)
1727{
1728        return register_virtio_driver(&virtio_net_driver);
1729}
1730
1731static void __exit fini(void)
1732{
1733        unregister_virtio_driver(&virtio_net_driver);
1734}
1735module_init(init);
1736module_exit(fini);
1737
1738MODULE_DEVICE_TABLE(virtio, id_table);
1739MODULE_DESCRIPTION("Virtio network driver");
1740MODULE_LICENSE("GPL");
1741
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