drivers/net/xen-netfront.c

   1 /*
   2  * Virtual network driver for conversing with remote driver backends.
   3  *
   4  * Copyright (c) 2002-2005, K A Fraser
   5  * Copyright (c) 2005, XenSource Ltd
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License version 2
   9  * as published by the Free Software Foundation; or, when distributed
  10  * separately from the Linux kernel or incorporated into other
  11  * software packages, subject to the following license:
  12  *
  13  * Permission is hereby granted, free of charge, to any person obtaining a copy
  14  * of this source file (the "Software"), to deal in the Software without
  15  * restriction, including without limitation the rights to use, copy, modify,
  16  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  17  * and to permit persons to whom the Software is furnished to do so, subject to
  18  * the following conditions:
  19  *
  20  * The above copyright notice and this permission notice shall be included in
  21  * all copies or substantial portions of the Software.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  24  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  25  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  26  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  27  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  28  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  29  * IN THE SOFTWARE.
  30  */
  31
  32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  33
  34 #include <linux/module.h>
  35 #include <linux/kernel.h>
  36 #include <linux/netdevice.h>
  37 #include <linux/etherdevice.h>
  38 #include <linux/skbuff.h>
  39 #include <linux/ethtool.h>
  40 #include <linux/if_ether.h>
  41 #include <net/tcp.h>
  42 #include <linux/udp.h>
  43 #include <linux/moduleparam.h>
  44 #include <linux/mm.h>
  45 #include <linux/slab.h>
  46 #include <net/ip.h>
  47
  48 #include <xen/xen.h>
  49 #include <xen/xenbus.h>
  50 #include <xen/events.h>
  51 #include <xen/page.h>
  52 #include <xen/platform_pci.h>
  53 #include <xen/grant_table.h>
  54
  55 #include <xen/interface/io/netif.h>
  56 #include <xen/interface/memory.h>
  57 #include <xen/interface/grant_table.h>
  58
  59 /* Module parameters */
  60 #define MAX_QUEUES_DEFAULT 8
  61 static unsigned int xennet_max_queues;
  62 module_param_named(max_queues, xennet_max_queues, uint, 0644);
  63 MODULE_PARM_DESC(max_queues,
  64                  "Maximum number of queues per virtual interface");
  65
  66 static const struct ethtool_ops xennet_ethtool_ops;
  67
  68 struct netfront_cb {
  69         int pull_to;
  70 };
  71
  72 #define NETFRONT_SKB_CB(skb)    ((struct netfront_cb *)((skb)->cb))
  73
  74 #define RX_COPY_THRESHOLD 256
  75
  76 #define GRANT_INVALID_REF       0
  77
  78 #define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, XEN_PAGE_SIZE)
  79 #define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, XEN_PAGE_SIZE)
  80
  81 /* Minimum number of Rx slots (includes slot for GSO metadata). */
  82 #define NET_RX_SLOTS_MIN (XEN_NETIF_NR_SLOTS_MIN + 1)
  83
  84 /* Queue name is interface name with "-qNNN" appended */
  85 #define QUEUE_NAME_SIZE (IFNAMSIZ + 6)
  86
  87 /* IRQ name is queue name with "-tx" or "-rx" appended */
  88 #define IRQ_NAME_SIZE (QUEUE_NAME_SIZE + 3)
  89
  90 static DECLARE_WAIT_QUEUE_HEAD(module_unload_q);
  91
  92 struct netfront_stats {
  93         u64                     packets;
  94         u64                     bytes;
  95         struct u64_stats_sync   syncp;
  96 };
  97
  98 struct netfront_info;
  99
 100 struct netfront_queue {
 101         unsigned int id; /* Queue ID, 0-based */
 102         char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
 103         struct netfront_info *info;
 104
 105         struct napi_struct napi;
 106
 107         /* Split event channels support, tx_* == rx_* when using
 108          * single event channel.
 109          */
 110         unsigned int tx_evtchn, rx_evtchn;
 111         unsigned int tx_irq, rx_irq;
 112         /* Only used when split event channels support is enabled */
 113         char tx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-tx */
 114         char rx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-rx */
 115
 116         spinlock_t   tx_lock;
 117         struct xen_netif_tx_front_ring tx;
 118         int tx_ring_ref;
 119
 120         /*
 121          * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
 122          * are linked from tx_skb_freelist through skb_entry.link.
 123          *
 124          *  NB. Freelist index entries are always going to be less than
 125          *  PAGE_OFFSET, whereas pointers to skbs will always be equal or
 126          *  greater than PAGE_OFFSET: we use this property to distinguish
 127          *  them.
 128          */
 129         union skb_entry {
 130                 struct sk_buff *skb;
 131                 unsigned long link;
 132         } tx_skbs[NET_TX_RING_SIZE];
 133         grant_ref_t gref_tx_head;
 134         grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
 135         struct page *grant_tx_page[NET_TX_RING_SIZE];
 136         unsigned tx_skb_freelist;
 137
 138         spinlock_t   rx_lock ____cacheline_aligned_in_smp;
 139         struct xen_netif_rx_front_ring rx;
 140         int rx_ring_ref;
 141
 142         struct timer_list rx_refill_timer;
 143
 144         struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
 145         grant_ref_t gref_rx_head;
 146         grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
 147 };
 148
 149 struct netfront_info {
 150         struct list_head list;
 151         struct net_device *netdev;
 152
 153         struct xenbus_device *xbdev;
 154
 155         /* Multi-queue support */
 156         struct netfront_queue *queues;
 157
 158         /* Statistics */
 159         struct netfront_stats __percpu *rx_stats;
 160         struct netfront_stats __percpu *tx_stats;
 161
 162         atomic_t rx_gso_checksum_fixup;
 163 };
 164
 165 struct netfront_rx_info {
 166         struct xen_netif_rx_response rx;
 167         struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
 168 };
 169
 170 static void skb_entry_set_link(union skb_entry *list, unsigned short id)
 171 {
 172         list->link = id;
 173 }
 174
 175 static int skb_entry_is_link(const union skb_entry *list)
 176 {
 177         BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link));
 178         return (unsigned long)list->skb < PAGE_OFFSET;
 179 }
 180
 181 /*
 182  * Access macros for acquiring freeing slots in tx_skbs[].
 183  */
 184
 185 static void add_id_to_freelist(unsigned *head, union skb_entry *list,
 186                                unsigned short id)
 187 {
 188         skb_entry_set_link(&list[id], *head);
 189         *head = id;
 190 }
 191
 192 static unsigned short get_id_from_freelist(unsigned *head,
 193                                            union skb_entry *list)
 194 {
 195         unsigned int id = *head;
 196         *head = list[id].link;
 197         return id;
 198 }
 199
 200 static int xennet_rxidx(RING_IDX idx)
 201 {
 202         return idx & (NET_RX_RING_SIZE - 1);
 203 }
 204
 205 static struct sk_buff *xennet_get_rx_skb(struct netfront_queue *queue,
 206                                          RING_IDX ri)
 207 {
 208         int i = xennet_rxidx(ri);
 209         struct sk_buff *skb = queue->rx_skbs[i];
 210         queue->rx_skbs[i] = NULL;
 211         return skb;
 212 }
 213
 214 static grant_ref_t xennet_get_rx_ref(struct netfront_queue *queue,
 215                                             RING_IDX ri)
 216 {
 217         int i = xennet_rxidx(ri);
 218         grant_ref_t ref = queue->grant_rx_ref[i];
 219         queue->grant_rx_ref[i] = GRANT_INVALID_REF;
 220         return ref;
 221 }
 222
 223 #ifdef CONFIG_SYSFS
 224 static const struct attribute_group xennet_dev_group;
 225 #endif
 226
 227 static bool xennet_can_sg(struct net_device *dev)
 228 {
 229         return dev->features & NETIF_F_SG;
 230 }
 231
 232
 233 static void rx_refill_timeout(struct timer_list *t)
 234 {
 235         struct netfront_queue *queue = from_timer(queue, t, rx_refill_timer);
 236         napi_schedule(&queue->napi);
 237 }
 238
 239 static int netfront_tx_slot_available(struct netfront_queue *queue)
 240 {
 241         return (queue->tx.req_prod_pvt - queue->tx.rsp_cons) <
 242                 (NET_TX_RING_SIZE - MAX_SKB_FRAGS - 2);
 243 }
 244
 245 static void xennet_maybe_wake_tx(struct netfront_queue *queue)
 246 {
 247         struct net_device *dev = queue->info->netdev;
 248         struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, queue->id);
 249
 250         if (unlikely(netif_tx_queue_stopped(dev_queue)) &&
 251             netfront_tx_slot_available(queue) &&
 252             likely(netif_running(dev)))
 253                 netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id));
 254 }
 255
 256
 257 static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue)
 258 {
 259         struct sk_buff *skb;
 260         struct page *page;
 261
 262         skb = __netdev_alloc_skb(queue->info->netdev,
 263                                  RX_COPY_THRESHOLD + NET_IP_ALIGN,
 264                                  GFP_ATOMIC | __GFP_NOWARN);
 265         if (unlikely(!skb))
 266                 return NULL;
 267
 268         page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 269         if (!page) {
 270                 kfree_skb(skb);
 271                 return NULL;
 272         }
 273         skb_add_rx_frag(skb, 0, page, 0, 0, PAGE_SIZE);
 274
 275         /* Align ip header to a 16 bytes boundary */
 276         skb_reserve(skb, NET_IP_ALIGN);
 277         skb->dev = queue->info->netdev;
 278
 279         return skb;
 280 }
 281
 282
 283 static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
 284 {
 285         RING_IDX req_prod = queue->rx.req_prod_pvt;
 286         int notify;
 287         int err = 0;
 288
 289         if (unlikely(!netif_carrier_ok(queue->info->netdev)))
 290                 return;
 291
 292         for (req_prod = queue->rx.req_prod_pvt;
 293              req_prod - queue->rx.rsp_cons < NET_RX_RING_SIZE;
 294              req_prod++) {
 295                 struct sk_buff *skb;
 296                 unsigned short id;
 297                 grant_ref_t ref;
 298                 struct page *page;
 299                 struct xen_netif_rx_request *req;
 300
 301                 skb = xennet_alloc_one_rx_buffer(queue);
 302                 if (!skb) {
 303                         err = -ENOMEM;
 304                         break;
 305                 }
 306
 307                 id = xennet_rxidx(req_prod);
 308
 309                 BUG_ON(queue->rx_skbs[id]);
 310                 queue->rx_skbs[id] = skb;
 311
 312                 ref = gnttab_claim_grant_reference(&queue->gref_rx_head);
 313                 WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
 314                 queue->grant_rx_ref[id] = ref;
 315
 316                 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
 317
 318                 req = RING_GET_REQUEST(&queue->rx, req_prod);
 319                 gnttab_page_grant_foreign_access_ref_one(ref,
 320                                                          queue->info->xbdev->otherend_id,
 321                                                          page,
 322                                                          0);
 323                 req->id = id;
 324                 req->gref = ref;
 325         }
 326
 327         queue->rx.req_prod_pvt = req_prod;
 328
 329         /* Try again later if there are not enough requests or skb allocation
 330          * failed.
 331          * Enough requests is quantified as the sum of newly created slots and
 332          * the unconsumed slots at the backend.
 333          */
 334         if (req_prod - queue->rx.rsp_cons < NET_RX_SLOTS_MIN ||
 335             unlikely(err)) {
 336                 mod_timer(&queue->rx_refill_timer, jiffies + (HZ/10));
 337                 return;
 338         }
 339
 340         wmb();          /* barrier so backend seens requests */
 341
 342         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->rx, notify);
 343         if (notify)
 344                 notify_remote_via_irq(queue->rx_irq);
 345 }
 346
 347 static int xennet_open(struct net_device *dev)
 348 {
 349         struct netfront_info *np = netdev_priv(dev);
 350         unsigned int num_queues = dev->real_num_tx_queues;
 351         unsigned int i = 0;
 352         struct netfront_queue *queue = NULL;
 353
 354         if (!np->queues)
 355                 return -ENODEV;
 356
 357         for (i = 0; i < num_queues; ++i) {
 358                 queue = &np->queues[i];
 359                 napi_enable(&queue->napi);
 360
 361                 spin_lock_bh(&queue->rx_lock);
 362                 if (netif_carrier_ok(dev)) {
 363                         xennet_alloc_rx_buffers(queue);
 364                         queue->rx.sring->rsp_event = queue->rx.rsp_cons + 1;
 365                         if (RING_HAS_UNCONSUMED_RESPONSES(&queue->rx))
 366                                 napi_schedule(&queue->napi);
 367                 }
 368                 spin_unlock_bh(&queue->rx_lock);
 369         }
 370
 371         netif_tx_start_all_queues(dev);
 372
 373         return 0;
 374 }
 375
 376 static void xennet_tx_buf_gc(struct netfront_queue *queue)
 377 {
 378         RING_IDX cons, prod;
 379         unsigned short id;
 380         struct sk_buff *skb;
 381         bool more_to_do;
 382
 383         BUG_ON(!netif_carrier_ok(queue->info->netdev));
 384
 385         do {
 386                 prod = queue->tx.sring->rsp_prod;
 387                 rmb(); /* Ensure we see responses up to 'rp'. */
 388
 389                 for (cons = queue->tx.rsp_cons; cons != prod; cons++) {
 390                         struct xen_netif_tx_response *txrsp;
 391
 392                         txrsp = RING_GET_RESPONSE(&queue->tx, cons);
 393                         if (txrsp->status == XEN_NETIF_RSP_NULL)
 394                                 continue;
 395
 396                         id  = txrsp->id;
 397                         skb = queue->tx_skbs[id].skb;
 398                         if (unlikely(gnttab_query_foreign_access(
 399                                 queue->grant_tx_ref[id]) != 0)) {
 400                                 pr_alert("%s: warning -- grant still in use by backend domain\n",
 401                                          __func__);
 402                                 BUG();
 403                         }
 404                         gnttab_end_foreign_access_ref(
 405                                 queue->grant_tx_ref[id], GNTMAP_readonly);
 406                         gnttab_release_grant_reference(
 407                                 &queue->gref_tx_head, queue->grant_tx_ref[id]);
 408                         queue->grant_tx_ref[id] = GRANT_INVALID_REF;
 409                         queue->grant_tx_page[id] = NULL;
 410                         add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, id);
 411                         dev_kfree_skb_irq(skb);
 412                 }
 413
 414                 queue->tx.rsp_cons = prod;
 415
 416                 RING_FINAL_CHECK_FOR_RESPONSES(&queue->tx, more_to_do);
 417         } while (more_to_do);
 418
 419         xennet_maybe_wake_tx(queue);
 420 }
 421
 422 struct xennet_gnttab_make_txreq {
 423         struct netfront_queue *queue;
 424         struct sk_buff *skb;
 425         struct page *page;
 426         struct xen_netif_tx_request *tx; /* Last request */
 427         unsigned int size;
 428 };
 429
 430 static void xennet_tx_setup_grant(unsigned long gfn, unsigned int offset,
 431                                   unsigned int len, void *data)
 432 {
 433         struct xennet_gnttab_make_txreq *info = data;
 434         unsigned int id;
 435         struct xen_netif_tx_request *tx;
 436         grant_ref_t ref;
 437         /* convenient aliases */
 438         struct page *page = info->page;
 439         struct netfront_queue *queue = info->queue;
 440         struct sk_buff *skb = info->skb;
 441
 442         id = get_id_from_freelist(&queue->tx_skb_freelist, queue->tx_skbs);
 443         tx = RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
 444         ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
 445         WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
 446
 447         gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,
 448                                         gfn, GNTMAP_readonly);
 449
 450         queue->tx_skbs[id].skb = skb;
 451         queue->grant_tx_page[id] = page;
 452         queue->grant_tx_ref[id] = ref;
 453
 454         tx->id = id;
 455         tx->gref = ref;
 456         tx->offset = offset;
 457         tx->size = len;
 458         tx->flags = 0;
 459
 460         info->tx = tx;
 461         info->size += tx->size;
 462 }
 463
 464 static struct xen_netif_tx_request *xennet_make_first_txreq(
 465         struct netfront_queue *queue, struct sk_buff *skb,
 466         struct page *page, unsigned int offset, unsigned int len)
 467 {
 468         struct xennet_gnttab_make_txreq info = {
 469                 .queue = queue,
 470                 .skb = skb,
 471                 .page = page,
 472                 .size = 0,
 473         };
 474
 475         gnttab_for_one_grant(page, offset, len, xennet_tx_setup_grant, &info);
 476
 477         return info.tx;
 478 }
 479
 480 static void xennet_make_one_txreq(unsigned long gfn, unsigned int offset,
 481                                   unsigned int len, void *data)
 482 {
 483         struct xennet_gnttab_make_txreq *info = data;
 484
 485         info->tx->flags |= XEN_NETTXF_more_data;
 486         skb_get(info->skb);
 487         xennet_tx_setup_grant(gfn, offset, len, data);
 488 }
 489
 490 static struct xen_netif_tx_request *xennet_make_txreqs(
 491         struct netfront_queue *queue, struct xen_netif_tx_request *tx,
 492         struct sk_buff *skb, struct page *page,
 493         unsigned int offset, unsigned int len)
 494 {
 495         struct xennet_gnttab_make_txreq info = {
 496                 .queue = queue,
 497                 .skb = skb,
 498                 .tx = tx,
 499         };
 500
 501         /* Skip unused frames from start of page */
 502         page += offset >> PAGE_SHIFT;
 503         offset &= ~PAGE_MASK;
 504
 505         while (len) {
 506                 info.page = page;
 507                 info.size = 0;
 508
 509                 gnttab_foreach_grant_in_range(page, offset, len,
 510                                               xennet_make_one_txreq,
 511                                               &info);
 512
 513                 page++;
 514                 offset = 0;
 515                 len -= info.size;
 516         }
 517
 518         return info.tx;
 519 }
 520
 521 /*
 522  * Count how many ring slots are required to send this skb. Each frag
 523  * might be a compound page.
 524  */
 525 static int xennet_count_skb_slots(struct sk_buff *skb)
 526 {
 527         int i, frags = skb_shinfo(skb)->nr_frags;
 528         int slots;
 529
 530         slots = gnttab_count_grant(offset_in_page(skb->data),
 531                                    skb_headlen(skb));
 532
 533         for (i = 0; i < frags; i++) {
 534                 skb_frag_t *frag = skb_shinfo(skb)->frags + i;
 535                 unsigned long size = skb_frag_size(frag);
 536                 unsigned long offset = frag->page_offset;
 537
 538                 /* Skip unused frames from start of page */
 539                 offset &= ~PAGE_MASK;
 540
 541                 slots += gnttab_count_grant(offset, size);
 542         }
 543
 544         return slots;
 545 }
 546
 547 static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb,
 548                                void *accel_priv, select_queue_fallback_t fallback)
 549 {
 550         unsigned int num_queues = dev->real_num_tx_queues;
 551         u32 hash;
 552         u16 queue_idx;
 553
 554         /* First, check if there is only one queue */
 555         if (num_queues == 1) {
 556                 queue_idx = 0;
 557         } else {
 558                 hash = skb_get_hash(skb);
 559                 queue_idx = hash % num_queues;
 560         }
 561
 562         return queue_idx;
 563 }
 564
 565 #define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1)
 566
 567 static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 568 {
 569         struct netfront_info *np = netdev_priv(dev);
 570         struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
 571         struct xen_netif_tx_request *tx, *first_tx;
 572         unsigned int i;
 573         int notify;
 574         int slots;
 575         struct page *page;
 576         unsigned int offset;
 577         unsigned int len;
 578         unsigned long flags;
 579         struct netfront_queue *queue = NULL;
 580         unsigned int num_queues = dev->real_num_tx_queues;
 581         u16 queue_index;
 582         struct sk_buff *nskb;
 583
 584         /* Drop the packet if no queues are set up */
 585         if (num_queues < 1)
 586                 goto drop;
 587         /* Determine which queue to transmit this SKB on */
 588         queue_index = skb_get_queue_mapping(skb);
 589         queue = &np->queues[queue_index];
 590
 591         /* If skb->len is too big for wire format, drop skb and alert
 592          * user about misconfiguration.
 593          */
 594         if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) {
 595                 net_alert_ratelimited(
 596                         "xennet: skb->len = %u, too big for wire format\n",
 597                         skb->len);
 598                 goto drop;
 599         }
 600
 601         slots = xennet_count_skb_slots(skb);
 602         if (unlikely(slots > MAX_XEN_SKB_FRAGS + 1)) {
 603                 net_dbg_ratelimited("xennet: skb rides the rocket: %d slots, %d bytes\n",
 604                                     slots, skb->len);
 605                 if (skb_linearize(skb))
 606                         goto drop;
 607         }
 608
 609         page = virt_to_page(skb->data);
 610         offset = offset_in_page(skb->data);
 611
 612         /* The first req should be at least ETH_HLEN size or the packet will be
 613          * dropped by netback.
 614          */
 615         if (unlikely(PAGE_SIZE - offset < ETH_HLEN)) {
 616                 nskb = skb_copy(skb, GFP_ATOMIC);
 617                 if (!nskb)
 618                         goto drop;
 619                 dev_consume_skb_any(skb);
 620                 skb = nskb;
 621                 page = virt_to_page(skb->data);
 622                 offset = offset_in_page(skb->data);
 623         }
 624
 625         len = skb_headlen(skb);
 626
 627         spin_lock_irqsave(&queue->tx_lock, flags);
 628
 629         if (unlikely(!netif_carrier_ok(dev) ||
 630                      (slots > 1 && !xennet_can_sg(dev)) ||
 631                      netif_needs_gso(skb, netif_skb_features(skb)))) {
 632                 spin_unlock_irqrestore(&queue->tx_lock, flags);
 633                 goto drop;
 634         }
 635
 636         /* First request for the linear area. */
 637         first_tx = tx = xennet_make_first_txreq(queue, skb,
 638                                                 page, offset, len);
 639         offset += tx->size;
 640         if (offset == PAGE_SIZE) {
 641                 page++;
 642                 offset = 0;
 643         }
 644         len -= tx->size;
 645
 646         if (skb->ip_summed == CHECKSUM_PARTIAL)
 647                 /* local packet? */
 648                 tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
 649         else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
 650                 /* remote but checksummed. */
 651                 tx->flags |= XEN_NETTXF_data_validated;
 652
 653         /* Optional extra info after the first request. */
 654         if (skb_shinfo(skb)->gso_size) {
 655                 struct xen_netif_extra_info *gso;
 656
 657                 gso = (struct xen_netif_extra_info *)
 658                         RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
 659
 660                 tx->flags |= XEN_NETTXF_extra_info;
 661
 662                 gso->u.gso.size = skb_shinfo(skb)->gso_size;
 663                 gso->u.gso.type = (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) ?
 664                         XEN_NETIF_GSO_TYPE_TCPV6 :
 665                         XEN_NETIF_GSO_TYPE_TCPV4;
 666                 gso->u.gso.pad = 0;
 667                 gso->u.gso.features = 0;
 668
 669                 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
 670                 gso->flags = 0;
 671         }
 672
 673         /* Requests for the rest of the linear area. */
 674         tx = xennet_make_txreqs(queue, tx, skb, page, offset, len);
 675
 676         /* Requests for all the frags. */
 677         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 678                 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 679                 tx = xennet_make_txreqs(queue, tx, skb,
 680                                         skb_frag_page(frag), frag->page_offset,
 681                                         skb_frag_size(frag));
 682         }
 683
 684         /* First request has the packet length. */
 685         first_tx->size = skb->len;
 686
 687         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
 688         if (notify)
 689                 notify_remote_via_irq(queue->tx_irq);
 690
 691         u64_stats_update_begin(&tx_stats->syncp);
 692         tx_stats->bytes += skb->len;
 693         tx_stats->packets++;
 694         u64_stats_update_end(&tx_stats->syncp);
 695
 696         /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
 697         xennet_tx_buf_gc(queue);
 698
 699         if (!netfront_tx_slot_available(queue))
 700                 netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
 701
 702         spin_unlock_irqrestore(&queue->tx_lock, flags);
 703
 704         return NETDEV_TX_OK;
 705
 706  drop:
 707         dev->stats.tx_dropped++;
 708         dev_kfree_skb_any(skb);
 709         return NETDEV_TX_OK;
 710 }
 711
 712 static int xennet_close(struct net_device *dev)
 713 {
 714         struct netfront_info *np = netdev_priv(dev);
 715         unsigned int num_queues = dev->real_num_tx_queues;
 716         unsigned int i;
 717         struct netfront_queue *queue;
 718         netif_tx_stop_all_queues(np->netdev);
 719         for (i = 0; i < num_queues; ++i) {
 720                 queue = &np->queues[i];
 721                 napi_disable(&queue->napi);
 722         }
 723         return 0;
 724 }
 725
 726 static void xennet_move_rx_slot(struct netfront_queue *queue, struct sk_buff *skb,
 727                                 grant_ref_t ref)
 728 {
 729         int new = xennet_rxidx(queue->rx.req_prod_pvt);
 730
 731         BUG_ON(queue->rx_skbs[new]);
 732         queue->rx_skbs[new] = skb;
 733         queue->grant_rx_ref[new] = ref;
 734         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->id = new;
 735         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->gref = ref;
 736         queue->rx.req_prod_pvt++;
 737 }
 738
 739 static int xennet_get_extras(struct netfront_queue *queue,
 740                              struct xen_netif_extra_info *extras,
 741                              RING_IDX rp)
 742
 743 {
 744         struct xen_netif_extra_info *extra;
 745         struct device *dev = &queue->info->netdev->dev;
 746         RING_IDX cons = queue->rx.rsp_cons;
 747         int err = 0;
 748
 749         do {
 750                 struct sk_buff *skb;
 751                 grant_ref_t ref;
 752
 753                 if (unlikely(cons + 1 == rp)) {
 754                         if (net_ratelimit())
 755                                 dev_warn(dev, "Missing extra info\n");
 756                         err = -EBADR;
 757                         break;
 758                 }
 759
 760                 extra = (struct xen_netif_extra_info *)
 761                         RING_GET_RESPONSE(&queue->rx, ++cons);
 762
 763                 if (unlikely(!extra->type ||
 764                              extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 765                         if (net_ratelimit())
 766                                 dev_warn(dev, "Invalid extra type: %d\n",
 767                                         extra->type);
 768                         err = -EINVAL;
 769                 } else {
 770                         memcpy(&extras[extra->type - 1], extra,
 771                                sizeof(*extra));
 772                 }
 773
 774                 skb = xennet_get_rx_skb(queue, cons);
 775                 ref = xennet_get_rx_ref(queue, cons);
 776                 xennet_move_rx_slot(queue, skb, ref);
 777         } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
 778
 779         queue->rx.rsp_cons = cons;
 780         return err;
 781 }
 782
 783 static int xennet_get_responses(struct netfront_queue *queue,
 784                                 struct netfront_rx_info *rinfo, RING_IDX rp,
 785                                 struct sk_buff_head *list)
 786 {
 787         struct xen_netif_rx_response *rx = &rinfo->rx;
 788         struct xen_netif_extra_info *extras = rinfo->extras;
 789         struct device *dev = &queue->info->netdev->dev;
 790         RING_IDX cons = queue->rx.rsp_cons;
 791         struct sk_buff *skb = xennet_get_rx_skb(queue, cons);
 792         grant_ref_t ref = xennet_get_rx_ref(queue, cons);
 793         int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD);
 794         int slots = 1;
 795         int err = 0;
 796         unsigned long ret;
 797
 798         if (rx->flags & XEN_NETRXF_extra_info) {
 799                 err = xennet_get_extras(queue, extras, rp);
 800                 cons = queue->rx.rsp_cons;
 801         }
 802
 803         for (;;) {
 804                 if (unlikely(rx->status < 0 ||
 805                              rx->offset + rx->status > XEN_PAGE_SIZE)) {
 806                         if (net_ratelimit())
 807                                 dev_warn(dev, "rx->offset: %u, size: %d\n",
 808                                          rx->offset, rx->status);
 809                         xennet_move_rx_slot(queue, skb, ref);
 810                         err = -EINVAL;
 811                         goto next;
 812                 }
 813
 814                 /*
 815                  * This definitely indicates a bug, either in this driver or in
 816                  * the backend driver. In future this should flag the bad
 817                  * situation to the system controller to reboot the backend.
 818                  */
 819                 if (ref == GRANT_INVALID_REF) {
 820                         if (net_ratelimit())
 821                                 dev_warn(dev, "Bad rx response id %d.\n",
 822                                          rx->id);
 823                         err = -EINVAL;
 824                         goto next;
 825                 }
 826
 827                 ret = gnttab_end_foreign_access_ref(ref, 0);
 828                 BUG_ON(!ret);
 829
 830                 gnttab_release_grant_reference(&queue->gref_rx_head, ref);
 831
 832                 __skb_queue_tail(list, skb);
 833
 834 next:
 835                 if (!(rx->flags & XEN_NETRXF_more_data))
 836                         break;
 837
 838                 if (cons + slots == rp) {
 839                         if (net_ratelimit())
 840                                 dev_warn(dev, "Need more slots\n");
 841                         err = -ENOENT;
 842                         break;
 843                 }
 844
 845                 rx = RING_GET_RESPONSE(&queue->rx, cons + slots);
 846                 skb = xennet_get_rx_skb(queue, cons + slots);
 847                 ref = xennet_get_rx_ref(queue, cons + slots);
 848                 slots++;
 849         }
 850
 851         if (unlikely(slots > max)) {
 852                 if (net_ratelimit())
 853                         dev_warn(dev, "Too many slots\n");
 854                 err = -E2BIG;
 855         }
 856
 857         if (unlikely(err))
 858                 queue->rx.rsp_cons = cons + slots;
 859
 860         return err;
 861 }
 862
 863 static int xennet_set_skb_gso(struct sk_buff *skb,
 864                               struct xen_netif_extra_info *gso)
 865 {
 866         if (!gso->u.gso.size) {
 867                 if (net_ratelimit())
 868                         pr_warn("GSO size must not be zero\n");
 869                 return -EINVAL;
 870         }
 871
 872         if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4 &&
 873             gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV6) {
 874                 if (net_ratelimit())
 875                         pr_warn("Bad GSO type %d\n", gso->u.gso.type);
 876                 return -EINVAL;
 877         }
 878
 879         skb_shinfo(skb)->gso_size = gso->u.gso.size;
 880         skb_shinfo(skb)->gso_type =
 881                 (gso->u.gso.type == XEN_NETIF_GSO_TYPE_TCPV4) ?
 882                 SKB_GSO_TCPV4 :
 883                 SKB_GSO_TCPV6;
 884
 885         /* Header must be checked, and gso_segs computed. */
 886         skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 887         skb_shinfo(skb)->gso_segs = 0;
 888
 889         return 0;
 890 }
 891
 892 static RING_IDX xennet_fill_frags(struct netfront_queue *queue,
 893                                   struct sk_buff *skb,
 894                                   struct sk_buff_head *list)
 895 {
 896         struct skb_shared_info *shinfo = skb_shinfo(skb);
 897         RING_IDX cons = queue->rx.rsp_cons;
 898         struct sk_buff *nskb;
 899
 900         while ((nskb = __skb_dequeue(list))) {
 901                 struct xen_netif_rx_response *rx =
 902                         RING_GET_RESPONSE(&queue->rx, ++cons);
 903                 skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0];
 904
 905                 if (shinfo->nr_frags == MAX_SKB_FRAGS) {
 906                         unsigned int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 907
 908                         BUG_ON(pull_to <= skb_headlen(skb));
 909                         __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
 910                 }
 911                 BUG_ON(shinfo->nr_frags >= MAX_SKB_FRAGS);
 912
 913                 skb_add_rx_frag(skb, shinfo->nr_frags, skb_frag_page(nfrag),
 914                                 rx->offset, rx->status, PAGE_SIZE);
 915
 916                 skb_shinfo(nskb)->nr_frags = 0;
 917                 kfree_skb(nskb);
 918         }
 919
 920         return cons;
 921 }
 922
 923 static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
 924 {
 925         bool recalculate_partial_csum = false;
 926
 927         /*
 928          * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 929          * peers can fail to set NETRXF_csum_blank when sending a GSO
 930          * frame. In this case force the SKB to CHECKSUM_PARTIAL and
 931          * recalculate the partial checksum.
 932          */
 933         if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
 934                 struct netfront_info *np = netdev_priv(dev);
 935                 atomic_inc(&np->rx_gso_checksum_fixup);
 936                 skb->ip_summed = CHECKSUM_PARTIAL;
 937                 recalculate_partial_csum = true;
 938         }
 939
 940         /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
 941         if (skb->ip_summed != CHECKSUM_PARTIAL)
 942                 return 0;
 943
 944         return skb_checksum_setup(skb, recalculate_partial_csum);
 945 }
 946
 947 static int handle_incoming_queue(struct netfront_queue *queue,
 948                                  struct sk_buff_head *rxq)
 949 {
 950         struct netfront_stats *rx_stats = this_cpu_ptr(queue->info->rx_stats);
 951         int packets_dropped = 0;
 952         struct sk_buff *skb;
 953
 954         while ((skb = __skb_dequeue(rxq)) != NULL) {
 955                 int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 956
 957                 if (pull_to > skb_headlen(skb))
 958                         __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
 959
 960                 /* Ethernet work: Delayed to here as it peeks the header. */
 961                 skb->protocol = eth_type_trans(skb, queue->info->netdev);
 962                 skb_reset_network_header(skb);
 963
 964                 if (checksum_setup(queue->info->netdev, skb)) {
 965                         kfree_skb(skb);
 966                         packets_dropped++;
 967                         queue->info->netdev->stats.rx_errors++;
 968                         continue;
 969                 }
 970
 971                 u64_stats_update_begin(&rx_stats->syncp);
 972                 rx_stats->packets++;
 973                 rx_stats->bytes += skb->len;
 974                 u64_stats_update_end(&rx_stats->syncp);
 975
 976                 /* Pass it up. */
 977                 napi_gro_receive(&queue->napi, skb);
 978         }
 979
 980         return packets_dropped;
 981 }
 982
 983 static int xennet_poll(struct napi_struct *napi, int budget)
 984 {
 985         struct netfront_queue *queue = container_of(napi, struct netfront_queue, napi);
 986         struct net_device *dev = queue->info->netdev;
 987         struct sk_buff *skb;
 988         struct netfront_rx_info rinfo;
 989         struct xen_netif_rx_response *rx = &rinfo.rx;
 990         struct xen_netif_extra_info *extras = rinfo.extras;
 991         RING_IDX i, rp;
 992         int work_done;
 993         struct sk_buff_head rxq;
 994         struct sk_buff_head errq;
 995         struct sk_buff_head tmpq;
 996         int err;
 997
 998         spin_lock(&queue->rx_lock);
 999
1000         skb_queue_head_init(&rxq);
1001         skb_queue_head_init(&errq);
1002         skb_queue_head_init(&tmpq);
1003
1004         rp = queue->rx.sring->rsp_prod;
1005         rmb(); /* Ensure we see queued responses up to 'rp'. */
1006
1007         i = queue->rx.rsp_cons;
1008         work_done = 0;
1009         while ((i != rp) && (work_done < budget)) {
1010                 memcpy(rx, RING_GET_RESPONSE(&queue->rx, i), sizeof(*rx));
1011                 memset(extras, 0, sizeof(rinfo.extras));
1012
1013                 err = xennet_get_responses(queue, &rinfo, rp, &tmpq);
1014
1015                 if (unlikely(err)) {
1016 err:
1017                         while ((skb = __skb_dequeue(&tmpq)))
1018                                 __skb_queue_tail(&errq, skb);
1019                         dev->stats.rx_errors++;
1020                         i = queue->rx.rsp_cons;
1021                         continue;
1022                 }
1023
1024                 skb = __skb_dequeue(&tmpq);
1025
1026                 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1027                         struct xen_netif_extra_info *gso;
1028                         gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1029
1030                         if (unlikely(xennet_set_skb_gso(skb, gso))) {
1031                                 __skb_queue_head(&tmpq, skb);
1032                                 queue->rx.rsp_cons += skb_queue_len(&tmpq);
1033                                 goto err;
1034                         }
1035                 }
1036
1037                 NETFRONT_SKB_CB(skb)->pull_to = rx->status;
1038                 if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD)
1039                         NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD;
1040
1041                 skb_shinfo(skb)->frags[0].page_offset = rx->offset;
1042                 skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status);
1043                 skb->data_len = rx->status;
1044                 skb->len += rx->status;
1045
1046                 i = xennet_fill_frags(queue, skb, &tmpq);
1047
1048                 if (rx->flags & XEN_NETRXF_csum_blank)
1049                         skb->ip_summed = CHECKSUM_PARTIAL;
1050                 else if (rx->flags & XEN_NETRXF_data_validated)
1051                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1052
1053                 __skb_queue_tail(&rxq, skb);
1054
1055                 queue->rx.rsp_cons = ++i;
1056                 work_done++;
1057         }
1058
1059         __skb_queue_purge(&errq);
1060
1061         work_done -= handle_incoming_queue(queue, &rxq);
1062
1063         xennet_alloc_rx_buffers(queue);
1064
1065         if (work_done < budget) {
1066                 int more_to_do = 0;
1067
1068                 napi_complete_done(napi, work_done);
1069
1070                 RING_FINAL_CHECK_FOR_RESPONSES(&queue->rx, more_to_do);
1071                 if (more_to_do)
1072                         napi_schedule(napi);
1073         }
1074
1075         spin_unlock(&queue->rx_lock);
1076
1077         return work_done;
1078 }
1079
1080 static int xennet_change_mtu(struct net_device *dev, int mtu)
1081 {
1082         int max = xennet_can_sg(dev) ? XEN_NETIF_MAX_TX_SIZE : ETH_DATA_LEN;
1083
1084         if (mtu > max)
1085                 return -EINVAL;
1086         dev->mtu = mtu;
1087         return 0;
1088 }
1089
1090 static void xennet_get_stats64(struct net_device *dev,
1091                                struct rtnl_link_stats64 *tot)
1092 {
1093         struct netfront_info *np = netdev_priv(dev);
1094         int cpu;
1095
1096         for_each_possible_cpu(cpu) {
1097                 struct netfront_stats *rx_stats = per_cpu_ptr(np->rx_stats, cpu);
1098                 struct netfront_stats *tx_stats = per_cpu_ptr(np->tx_stats, cpu);
1099                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
1100                 unsigned int start;
1101
1102                 do {
1103                         start = u64_stats_fetch_begin_irq(&tx_stats->syncp);
1104                         tx_packets = tx_stats->packets;
1105                         tx_bytes = tx_stats->bytes;
1106                 } while (u64_stats_fetch_retry_irq(&tx_stats->syncp, start));
1107
1108                 do {
1109                         start = u64_stats_fetch_begin_irq(&rx_stats->syncp);
1110                         rx_packets = rx_stats->packets;
1111                         rx_bytes = rx_stats->bytes;
1112                 } while (u64_stats_fetch_retry_irq(&rx_stats->syncp, start));
1113
1114                 tot->rx_packets += rx_packets;
1115                 tot->tx_packets += tx_packets;
1116                 tot->rx_bytes   += rx_bytes;
1117                 tot->tx_bytes   += tx_bytes;
1118         }
1119
1120         tot->rx_errors  = dev->stats.rx_errors;
1121         tot->tx_dropped = dev->stats.tx_dropped;
1122 }
1123
1124 static void xennet_release_tx_bufs(struct netfront_queue *queue)
1125 {
1126         struct sk_buff *skb;
1127         int i;
1128
1129         for (i = 0; i < NET_TX_RING_SIZE; i++) {
1130                 /* Skip over entries which are actually freelist references */
1131                 if (skb_entry_is_link(&queue->tx_skbs[i]))
1132                         continue;
1133
1134                 skb = queue->tx_skbs[i].skb;
1135                 get_page(queue->grant_tx_page[i]);
1136                 gnttab_end_foreign_access(queue->grant_tx_ref[i],
1137                                           GNTMAP_readonly,
1138                                           (unsigned long)page_address(queue->grant_tx_page[i]));
1139                 queue->grant_tx_page[i] = NULL;
1140                 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1141                 add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, i);
1142                 dev_kfree_skb_irq(skb);
1143         }
1144 }
1145
1146 static void xennet_release_rx_bufs(struct netfront_queue *queue)
1147 {
1148         int id, ref;
1149
1150         spin_lock_bh(&queue->rx_lock);
1151
1152         for (id = 0; id < NET_RX_RING_SIZE; id++) {
1153                 struct sk_buff *skb;
1154                 struct page *page;
1155
1156                 skb = queue->rx_skbs[id];
1157                 if (!skb)
1158                         continue;
1159
1160                 ref = queue->grant_rx_ref[id];
1161                 if (ref == GRANT_INVALID_REF)
1162                         continue;
1163
1164                 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
1165
1166                 /* gnttab_end_foreign_access() needs a page ref until
1167                  * foreign access is ended (which may be deferred).
1168                  */
1169                 get_page(page);
1170                 gnttab_end_foreign_access(ref, 0,
1171                                           (unsigned long)page_address(page));
1172                 queue->grant_rx_ref[id] = GRANT_INVALID_REF;
1173
1174                 kfree_skb(skb);
1175         }
1176
1177         spin_unlock_bh(&queue->rx_lock);
1178 }
1179
1180 static netdev_features_t xennet_fix_features(struct net_device *dev,
1181         netdev_features_t features)
1182 {
1183         struct netfront_info *np = netdev_priv(dev);
1184
1185         if (features & NETIF_F_SG &&
1186             !xenbus_read_unsigned(np->xbdev->otherend, "feature-sg", 0))
1187                 features &= ~NETIF_F_SG;
1188
1189         if (features & NETIF_F_IPV6_CSUM &&
1190             !xenbus_read_unsigned(np->xbdev->otherend,
1191                                   "feature-ipv6-csum-offload", 0))
1192                 features &= ~NETIF_F_IPV6_CSUM;
1193
1194         if (features & NETIF_F_TSO &&
1195             !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv4", 0))
1196                 features &= ~NETIF_F_TSO;
1197
1198         if (features & NETIF_F_TSO6 &&
1199             !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv6", 0))
1200                 features &= ~NETIF_F_TSO6;
1201
1202         return features;
1203 }
1204
1205 static int xennet_set_features(struct net_device *dev,
1206         netdev_features_t features)
1207 {
1208         if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) {
1209                 netdev_info(dev, "Reducing MTU because no SG offload");
1210                 dev->mtu = ETH_DATA_LEN;
1211         }
1212
1213         return 0;
1214 }
1215
1216 static irqreturn_t xennet_tx_interrupt(int irq, void *dev_id)
1217 {
1218         struct netfront_queue *queue = dev_id;
1219         unsigned long flags;
1220
1221         spin_lock_irqsave(&queue->tx_lock, flags);
1222         xennet_tx_buf_gc(queue);
1223         spin_unlock_irqrestore(&queue->tx_lock, flags);
1224
1225         return IRQ_HANDLED;
1226 }
1227
1228 static irqreturn_t xennet_rx_interrupt(int irq, void *dev_id)
1229 {
1230         struct netfront_queue *queue = dev_id;
1231         struct net_device *dev = queue->info->netdev;
1232
1233         if (likely(netif_carrier_ok(dev) &&
1234                    RING_HAS_UNCONSUMED_RESPONSES(&queue->rx)))
1235                 napi_schedule(&queue->napi);
1236
1237         return IRQ_HANDLED;
1238 }
1239
1240 static irqreturn_t xennet_interrupt(int irq, void *dev_id)
1241 {
1242         xennet_tx_interrupt(irq, dev_id);
1243         xennet_rx_interrupt(irq, dev_id);
1244         return IRQ_HANDLED;
1245 }
1246
1247 #ifdef CONFIG_NET_POLL_CONTROLLER
1248 static void xennet_poll_controller(struct net_device *dev)
1249 {
1250         /* Poll each queue */
1251         struct netfront_info *info = netdev_priv(dev);
1252         unsigned int num_queues = dev->real_num_tx_queues;
1253         unsigned int i;
1254         for (i = 0; i < num_queues; ++i)
1255                 xennet_interrupt(0, &info->queues[i]);
1256 }
1257 #endif
1258
1259 static const struct net_device_ops xennet_netdev_ops = {
1260         .ndo_open            = xennet_open,
1261         .ndo_stop            = xennet_close,
1262         .ndo_start_xmit      = xennet_start_xmit,
1263         .ndo_change_mtu      = xennet_change_mtu,
1264         .ndo_get_stats64     = xennet_get_stats64,
1265         .ndo_set_mac_address = eth_mac_addr,
1266         .ndo_validate_addr   = eth_validate_addr,
1267         .ndo_fix_features    = xennet_fix_features,
1268         .ndo_set_features    = xennet_set_features,
1269         .ndo_select_queue    = xennet_select_queue,
1270 #ifdef CONFIG_NET_POLL_CONTROLLER
1271         .ndo_poll_controller = xennet_poll_controller,
1272 #endif
1273 };
1274
1275 static void xennet_free_netdev(struct net_device *netdev)
1276 {
1277         struct netfront_info *np = netdev_priv(netdev);
1278
1279         free_percpu(np->rx_stats);
1280         free_percpu(np->tx_stats);
1281         free_netdev(netdev);
1282 }
1283
1284 static struct net_device *xennet_create_dev(struct xenbus_device *dev)
1285 {
1286         int err;
1287         struct net_device *netdev;
1288         struct netfront_info *np;
1289
1290         netdev = alloc_etherdev_mq(sizeof(struct netfront_info), xennet_max_queues);
1291         if (!netdev)
1292                 return ERR_PTR(-ENOMEM);
1293
1294         np                   = netdev_priv(netdev);
1295         np->xbdev            = dev;
1296
1297         np->queues = NULL;
1298
1299         err = -ENOMEM;
1300         np->rx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1301         if (np->rx_stats == NULL)
1302                 goto exit;
1303         np->tx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1304         if (np->tx_stats == NULL)
1305                 goto exit;
1306
1307         netdev->netdev_ops      = &xennet_netdev_ops;
1308
1309         netdev->features        = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
1310                                   NETIF_F_GSO_ROBUST;
1311         netdev->hw_features     = NETIF_F_SG |
1312                                   NETIF_F_IPV6_CSUM |
1313                                   NETIF_F_TSO | NETIF_F_TSO6;
1314
1315         /*
1316          * Assume that all hw features are available for now. This set
1317          * will be adjusted by the call to netdev_update_features() in
1318          * xennet_connect() which is the earliest point where we can
1319          * negotiate with the backend regarding supported features.
1320          */
1321         netdev->features |= netdev->hw_features;
1322
1323         netdev->ethtool_ops = &xennet_ethtool_ops;
1324         netdev->min_mtu = ETH_MIN_MTU;
1325         netdev->max_mtu = XEN_NETIF_MAX_TX_SIZE;
1326         SET_NETDEV_DEV(netdev, &dev->dev);
1327
1328         np->netdev = netdev;
1329
1330         netif_carrier_off(netdev);
1331
1332         xenbus_switch_state(dev, XenbusStateInitialising);
1333         return netdev;
1334
1335  exit:
1336         xennet_free_netdev(netdev);
1337         return ERR_PTR(err);
1338 }
1339
1340 /**
1341  * Entry point to this code when a new device is created.  Allocate the basic
1342  * structures and the ring buffers for communication with the backend, and
1343  * inform the backend of the appropriate details for those.
1344  */
1345 static int netfront_probe(struct xenbus_device *dev,
1346                           const struct xenbus_device_id *id)
1347 {
1348         int err;
1349         struct net_device *netdev;
1350         struct netfront_info *info;
1351
1352         netdev = xennet_create_dev(dev);
1353         if (IS_ERR(netdev)) {
1354                 err = PTR_ERR(netdev);
1355                 xenbus_dev_fatal(dev, err, "creating netdev");
1356                 return err;
1357         }
1358
1359         info = netdev_priv(netdev);
1360         dev_set_drvdata(&dev->dev, info);
1361 #ifdef CONFIG_SYSFS
1362         info->netdev->sysfs_groups[0] = &xennet_dev_group;
1363 #endif
1364
1365         return 0;
1366 }
1367
1368 static void xennet_end_access(int ref, void *page)
1369 {
1370         /* This frees the page as a side-effect */
1371         if (ref != GRANT_INVALID_REF)
1372                 gnttab_end_foreign_access(ref, 0, (unsigned long)page);
1373 }
1374
1375 static void xennet_disconnect_backend(struct netfront_info *info)
1376 {
1377         unsigned int i = 0;
1378         unsigned int num_queues = info->netdev->real_num_tx_queues;
1379
1380         netif_carrier_off(info->netdev);
1381
1382         for (i = 0; i < num_queues && info->queues; ++i) {
1383                 struct netfront_queue *queue = &info->queues[i];
1384
1385                 del_timer_sync(&queue->rx_refill_timer);
1386
1387                 if (queue->tx_irq && (queue->tx_irq == queue->rx_irq))
1388                         unbind_from_irqhandler(queue->tx_irq, queue);
1389                 if (queue->tx_irq && (queue->tx_irq != queue->rx_irq)) {
1390                         unbind_from_irqhandler(queue->tx_irq, queue);
1391                         unbind_from_irqhandler(queue->rx_irq, queue);
1392                 }
1393                 queue->tx_evtchn = queue->rx_evtchn = 0;
1394                 queue->tx_irq = queue->rx_irq = 0;
1395
1396                 if (netif_running(info->netdev))
1397                         napi_synchronize(&queue->napi);
1398
1399                 xennet_release_tx_bufs(queue);
1400                 xennet_release_rx_bufs(queue);
1401                 gnttab_free_grant_references(queue->gref_tx_head);
1402                 gnttab_free_grant_references(queue->gref_rx_head);
1403
1404                 /* End access and free the pages */
1405                 xennet_end_access(queue->tx_ring_ref, queue->tx.sring);
1406                 xennet_end_access(queue->rx_ring_ref, queue->rx.sring);
1407
1408                 queue->tx_ring_ref = GRANT_INVALID_REF;
1409                 queue->rx_ring_ref = GRANT_INVALID_REF;
1410                 queue->tx.sring = NULL;
1411                 queue->rx.sring = NULL;
1412         }
1413 }
1414
1415 /**
1416  * We are reconnecting to the backend, due to a suspend/resume, or a backend
1417  * driver restart.  We tear down our netif structure and recreate it, but
1418  * leave the device-layer structures intact so that this is transparent to the
1419  * rest of the kernel.
1420  */
1421 static int netfront_resume(struct xenbus_device *dev)
1422 {
1423         struct netfront_info *info = dev_get_drvdata(&dev->dev);
1424
1425         dev_dbg(&dev->dev, "%s\n", dev->nodename);
1426
1427         xennet_disconnect_backend(info);
1428         return 0;
1429 }
1430
1431 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
1432 {
1433         char *s, *e, *macstr;
1434         int i;
1435
1436         macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
1437         if (IS_ERR(macstr))
1438                 return PTR_ERR(macstr);
1439
1440         for (i = 0; i < ETH_ALEN; i++) {
1441                 mac[i] = simple_strtoul(s, &e, 16);
1442                 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
1443                         kfree(macstr);
1444                         return -ENOENT;
1445                 }
1446                 s = e+1;
1447         }
1448
1449         kfree(macstr);
1450         return 0;
1451 }
1452
1453 static int setup_netfront_single(struct netfront_queue *queue)
1454 {
1455         int err;
1456
1457         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1458         if (err < 0)
1459                 goto fail;
1460
1461         err = bind_evtchn_to_irqhandler(queue->tx_evtchn,
1462                                         xennet_interrupt,
1463                                         0, queue->info->netdev->name, queue);
1464         if (err < 0)
1465                 goto bind_fail;
1466         queue->rx_evtchn = queue->tx_evtchn;
1467         queue->rx_irq = queue->tx_irq = err;
1468
1469         return 0;
1470
1471 bind_fail:
1472         xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1473         queue->tx_evtchn = 0;
1474 fail:
1475         return err;
1476 }
1477
1478 static int setup_netfront_split(struct netfront_queue *queue)
1479 {
1480         int err;
1481
1482         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1483         if (err < 0)
1484                 goto fail;
1485         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->rx_evtchn);
1486         if (err < 0)
1487                 goto alloc_rx_evtchn_fail;
1488
1489         snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
1490                  "%s-tx", queue->name);
1491         err = bind_evtchn_to_irqhandler(queue->tx_evtchn,
1492                                         xennet_tx_interrupt,
1493                                         0, queue->tx_irq_name, queue);
1494         if (err < 0)
1495                 goto bind_tx_fail;
1496         queue->tx_irq = err;
1497
1498         snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
1499                  "%s-rx", queue->name);
1500         err = bind_evtchn_to_irqhandler(queue->rx_evtchn,
1501                                         xennet_rx_interrupt,
1502                                         0, queue->rx_irq_name, queue);
1503         if (err < 0)
1504                 goto bind_rx_fail;
1505         queue->rx_irq = err;
1506
1507         return 0;
1508
1509 bind_rx_fail:
1510         unbind_from_irqhandler(queue->tx_irq, queue);
1511         queue->tx_irq = 0;
1512 bind_tx_fail:
1513         xenbus_free_evtchn(queue->info->xbdev, queue->rx_evtchn);
1514         queue->rx_evtchn = 0;
1515 alloc_rx_evtchn_fail:
1516         xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1517         queue->tx_evtchn = 0;
1518 fail:
1519         return err;
1520 }
1521
1522 static int setup_netfront(struct xenbus_device *dev,
1523                         struct netfront_queue *queue, unsigned int feature_split_evtchn)
1524 {
1525         struct xen_netif_tx_sring *txs;
1526         struct xen_netif_rx_sring *rxs;
1527         grant_ref_t gref;
1528         int err;
1529
1530         queue->tx_ring_ref = GRANT_INVALID_REF;
1531         queue->rx_ring_ref = GRANT_INVALID_REF;
1532         queue->rx.sring = NULL;
1533         queue->tx.sring = NULL;
1534
1535         txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1536         if (!txs) {
1537                 err = -ENOMEM;
1538                 xenbus_dev_fatal(dev, err, "allocating tx ring page");
1539                 goto fail;
1540         }
1541         SHARED_RING_INIT(txs);
1542         FRONT_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
1543
1544         err = xenbus_grant_ring(dev, txs, 1, &gref);
1545         if (err < 0)
1546                 goto grant_tx_ring_fail;
1547         queue->tx_ring_ref = gref;
1548
1549         rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1550         if (!rxs) {
1551                 err = -ENOMEM;
1552                 xenbus_dev_fatal(dev, err, "allocating rx ring page");
1553                 goto alloc_rx_ring_fail;
1554         }
1555         SHARED_RING_INIT(rxs);
1556         FRONT_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
1557
1558         err = xenbus_grant_ring(dev, rxs, 1, &gref);
1559         if (err < 0)
1560                 goto grant_rx_ring_fail;
1561         queue->rx_ring_ref = gref;
1562
1563         if (feature_split_evtchn)
1564                 err = setup_netfront_split(queue);
1565         /* setup single event channel if
1566          *  a) feature-split-event-channels == 0
1567          *  b) feature-split-event-channels == 1 but failed to setup
1568          */
1569         if (!feature_split_evtchn || (feature_split_evtchn && err))
1570                 err = setup_netfront_single(queue);
1571
1572         if (err)
1573                 goto alloc_evtchn_fail;
1574
1575         return 0;
1576
1577         /* If we fail to setup netfront, it is safe to just revoke access to
1578          * granted pages because backend is not accessing it at this point.
1579          */
1580 alloc_evtchn_fail:
1581         gnttab_end_foreign_access_ref(queue->rx_ring_ref, 0);
1582 grant_rx_ring_fail:
1583         free_page((unsigned long)rxs);
1584 alloc_rx_ring_fail:
1585         gnttab_end_foreign_access_ref(queue->tx_ring_ref, 0);
1586 grant_tx_ring_fail:
1587         free_page((unsigned long)txs);
1588 fail:
1589         return err;
1590 }
1591
1592 /* Queue-specific initialisation
1593  * This used to be done in xennet_create_dev() but must now
1594  * be run per-queue.
1595  */
1596 static int xennet_init_queue(struct netfront_queue *queue)
1597 {
1598         unsigned short i;
1599         int err = 0;
1600
1601         spin_lock_init(&queue->tx_lock);
1602         spin_lock_init(&queue->rx_lock);
1603
1604         timer_setup(&queue->rx_refill_timer, rx_refill_timeout, 0);
1605
1606         snprintf(queue->name, sizeof(queue->name), "%s-q%u",
1607                  queue->info->netdev->name, queue->id);
1608
1609         /* Initialise tx_skbs as a free chain containing every entry. */
1610         queue->tx_skb_freelist = 0;
1611         for (i = 0; i < NET_TX_RING_SIZE; i++) {
1612                 skb_entry_set_link(&queue->tx_skbs[i], i+1);
1613                 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1614                 queue->grant_tx_page[i] = NULL;
1615         }
1616
1617         /* Clear out rx_skbs */
1618         for (i = 0; i < NET_RX_RING_SIZE; i++) {
1619                 queue->rx_skbs[i] = NULL;
1620                 queue->grant_rx_ref[i] = GRANT_INVALID_REF;
1621         }
1622
1623         /* A grant for every tx ring slot */
1624         if (gnttab_alloc_grant_references(NET_TX_RING_SIZE,
1625                                           &queue->gref_tx_head) < 0) {
1626                 pr_alert("can't alloc tx grant refs\n");
1627                 err = -ENOMEM;
1628                 goto exit;
1629         }
1630
1631         /* A grant for every rx ring slot */
1632         if (gnttab_alloc_grant_references(NET_RX_RING_SIZE,
1633                                           &queue->gref_rx_head) < 0) {
1634                 pr_alert("can't alloc rx grant refs\n");
1635                 err = -ENOMEM;
1636                 goto exit_free_tx;
1637         }
1638
1639         return 0;
1640
1641  exit_free_tx:
1642         gnttab_free_grant_references(queue->gref_tx_head);
1643  exit:
1644         return err;
1645 }
1646
1647 static int write_queue_xenstore_keys(struct netfront_queue *queue,
1648                            struct xenbus_transaction *xbt, int write_hierarchical)
1649 {
1650         /* Write the queue-specific keys into XenStore in the traditional
1651          * way for a single queue, or in a queue subkeys for multiple
1652          * queues.
1653          */
1654         struct xenbus_device *dev = queue->info->xbdev;
1655         int err;
1656         const char *message;
1657         char *path;
1658         size_t pathsize;
1659
1660         /* Choose the correct place to write the keys */
1661         if (write_hierarchical) {
1662                 pathsize = strlen(dev->nodename) + 10;
1663                 path = kzalloc(pathsize, GFP_KERNEL);
1664                 if (!path) {
1665                         err = -ENOMEM;
1666                         message = "out of memory while writing ring references";
1667                         goto error;
1668                 }
1669                 snprintf(path, pathsize, "%s/queue-%u",
1670                                 dev->nodename, queue->id);
1671         } else {
1672                 path = (char *)dev->nodename;
1673         }
1674
1675         /* Write ring references */
1676         err = xenbus_printf(*xbt, path, "tx-ring-ref", "%u",
1677                         queue->tx_ring_ref);
1678         if (err) {
1679                 message = "writing tx-ring-ref";
1680                 goto error;
1681         }
1682
1683         err = xenbus_printf(*xbt, path, "rx-ring-ref", "%u",
1684                         queue->rx_ring_ref);
1685         if (err) {
1686                 message = "writing rx-ring-ref";
1687                 goto error;
1688         }
1689
1690         /* Write event channels; taking into account both shared
1691          * and split event channel scenarios.
1692          */
1693         if (queue->tx_evtchn == queue->rx_evtchn) {
1694                 /* Shared event channel */
1695                 err = xenbus_printf(*xbt, path,
1696                                 "event-channel", "%u", queue->tx_evtchn);
1697                 if (err) {
1698                         message = "writing event-channel";
1699                         goto error;
1700                 }
1701         } else {
1702                 /* Split event channels */
1703                 err = xenbus_printf(*xbt, path,
1704                                 "event-channel-tx", "%u", queue->tx_evtchn);
1705                 if (err) {
1706                         message = "writing event-channel-tx";
1707                         goto error;
1708                 }
1709
1710                 err = xenbus_printf(*xbt, path,
1711                                 "event-channel-rx", "%u", queue->rx_evtchn);
1712                 if (err) {
1713                         message = "writing event-channel-rx";
1714                         goto error;
1715                 }
1716         }
1717
1718         if (write_hierarchical)
1719                 kfree(path);
1720         return 0;
1721
1722 error:
1723         if (write_hierarchical)
1724                 kfree(path);
1725         xenbus_dev_fatal(dev, err, "%s", message);
1726         return err;
1727 }
1728
1729 static void xennet_destroy_queues(struct netfront_info *info)
1730 {
1731         unsigned int i;
1732
1733         for (i = 0; i < info->netdev->real_num_tx_queues; i++) {
1734                 struct netfront_queue *queue = &info->queues[i];
1735
1736                 if (netif_running(info->netdev))
1737                         napi_disable(&queue->napi);
1738                 netif_napi_del(&queue->napi);
1739         }
1740
1741         kfree(info->queues);
1742         info->queues = NULL;
1743 }
1744
1745 static int xennet_create_queues(struct netfront_info *info,
1746                                 unsigned int *num_queues)
1747 {
1748         unsigned int i;
1749         int ret;
1750
1751         info->queues = kcalloc(*num_queues, sizeof(struct netfront_queue),
1752                                GFP_KERNEL);
1753         if (!info->queues)
1754                 return -ENOMEM;
1755
1756         for (i = 0; i < *num_queues; i++) {
1757                 struct netfront_queue *queue = &info->queues[i];
1758
1759                 queue->id = i;
1760                 queue->info = info;
1761
1762                 ret = xennet_init_queue(queue);
1763                 if (ret < 0) {
1764                         dev_warn(&info->xbdev->dev,
1765                                  "only created %d queues\n", i);
1766                         *num_queues = i;
1767                         break;
1768                 }
1769
1770                 netif_napi_add(queue->info->netdev, &queue->napi,
1771                                xennet_poll, 64);
1772                 if (netif_running(info->netdev))
1773                         napi_enable(&queue->napi);
1774         }
1775
1776         netif_set_real_num_tx_queues(info->netdev, *num_queues);
1777
1778         if (*num_queues == 0) {
1779                 dev_err(&info->xbdev->dev, "no queues\n");
1780                 return -EINVAL;
1781         }
1782         return 0;
1783 }
1784
1785 /* Common code used when first setting up, and when resuming. */
1786 static int talk_to_netback(struct xenbus_device *dev,
1787                            struct netfront_info *info)
1788 {
1789         const char *message;
1790         struct xenbus_transaction xbt;
1791         int err;
1792         unsigned int feature_split_evtchn;
1793         unsigned int i = 0;
1794         unsigned int max_queues = 0;
1795         struct netfront_queue *queue = NULL;
1796         unsigned int num_queues = 1;
1797
1798         info->netdev->irq = 0;
1799
1800         /* Check if backend supports multiple queues */
1801         max_queues = xenbus_read_unsigned(info->xbdev->otherend,
1802                                           "multi-queue-max-queues", 1);
1803         num_queues = min(max_queues, xennet_max_queues);
1804
1805         /* Check feature-split-event-channels */
1806         feature_split_evtchn = xenbus_read_unsigned(info->xbdev->otherend,
1807                                         "feature-split-event-channels", 0);
1808
1809         /* Read mac addr. */
1810         err = xen_net_read_mac(dev, info->netdev->dev_addr);
1811         if (err) {
1812                 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
1813                 goto out;
1814         }
1815
1816         rtnl_lock();
1817         if (info->queues)
1818                 xennet_destroy_queues(info);
1819
1820         err = xennet_create_queues(info, &num_queues);
1821         if (err < 0) {
1822                 xenbus_dev_fatal(dev, err, "creating queues");
1823                 kfree(info->queues);
1824                 info->queues = NULL;
1825                 goto out;
1826         }
1827         rtnl_unlock();
1828
1829         /* Create shared ring, alloc event channel -- for each queue */
1830         for (i = 0; i < num_queues; ++i) {
1831                 queue = &info->queues[i];
1832                 err = setup_netfront(dev, queue, feature_split_evtchn);
1833                 if (err)
1834                         goto destroy_ring;
1835         }
1836
1837 again:
1838         err = xenbus_transaction_start(&xbt);
1839         if (err) {
1840                 xenbus_dev_fatal(dev, err, "starting transaction");
1841                 goto destroy_ring;
1842         }
1843
1844         if (xenbus_exists(XBT_NIL,
1845                           info->xbdev->otherend, "multi-queue-max-queues")) {
1846                 /* Write the number of queues */
1847                 err = xenbus_printf(xbt, dev->nodename,
1848                                     "multi-queue-num-queues", "%u", num_queues);
1849                 if (err) {
1850                         message = "writing multi-queue-num-queues";
1851                         goto abort_transaction_no_dev_fatal;
1852                 }
1853         }
1854
1855         if (num_queues == 1) {
1856                 err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
1857                 if (err)
1858                         goto abort_transaction_no_dev_fatal;
1859         } else {
1860                 /* Write the keys for each queue */
1861                 for (i = 0; i < num_queues; ++i) {
1862                         queue = &info->queues[i];
1863                         err = write_queue_xenstore_keys(queue, &xbt, 1); /* hierarchical */
1864                         if (err)
1865                                 goto abort_transaction_no_dev_fatal;
1866                 }
1867         }
1868
1869         /* The remaining keys are not queue-specific */
1870         err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
1871                             1);
1872         if (err) {
1873                 message = "writing request-rx-copy";
1874                 goto abort_transaction;
1875         }
1876
1877         err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
1878         if (err) {
1879                 message = "writing feature-rx-notify";
1880                 goto abort_transaction;
1881         }
1882
1883         err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
1884         if (err) {
1885                 message = "writing feature-sg";
1886                 goto abort_transaction;
1887         }
1888
1889         err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
1890         if (err) {
1891                 message = "writing feature-gso-tcpv4";
1892                 goto abort_transaction;
1893         }
1894
1895         err = xenbus_write(xbt, dev->nodename, "feature-gso-tcpv6", "1");
1896         if (err) {
1897                 message = "writing feature-gso-tcpv6";
1898                 goto abort_transaction;
1899         }
1900
1901         err = xenbus_write(xbt, dev->nodename, "feature-ipv6-csum-offload",
1902                            "1");
1903         if (err) {
1904                 message = "writing feature-ipv6-csum-offload";
1905                 goto abort_transaction;
1906         }
1907
1908         err = xenbus_transaction_end(xbt, 0);
1909         if (err) {
1910                 if (err == -EAGAIN)
1911                         goto again;
1912                 xenbus_dev_fatal(dev, err, "completing transaction");
1913                 goto destroy_ring;
1914         }
1915
1916         return 0;
1917
1918  abort_transaction:
1919         xenbus_dev_fatal(dev, err, "%s", message);
1920 abort_transaction_no_dev_fatal:
1921         xenbus_transaction_end(xbt, 1);
1922  destroy_ring:
1923         xennet_disconnect_backend(info);
1924         rtnl_lock();
1925         xennet_destroy_queues(info);
1926  out:
1927         rtnl_unlock();
1928         device_unregister(&dev->dev);
1929         return err;
1930 }
1931
1932 static int xennet_connect(struct net_device *dev)
1933 {
1934         struct netfront_info *np = netdev_priv(dev);
1935         unsigned int num_queues = 0;
1936         int err;
1937         unsigned int j = 0;
1938         struct netfront_queue *queue = NULL;
1939
1940         if (!xenbus_read_unsigned(np->xbdev->otherend, "feature-rx-copy", 0)) {
1941                 dev_info(&dev->dev,
1942                          "backend does not support copying receive path\n");
1943                 return -ENODEV;
1944         }
1945
1946         err = talk_to_netback(np->xbdev, np);
1947         if (err)
1948                 return err;
1949
1950         /* talk_to_netback() sets the correct number of queues */
1951         num_queues = dev->real_num_tx_queues;
1952
1953         rtnl_lock();
1954         netdev_update_features(dev);
1955         rtnl_unlock();
1956
1957         if (dev->reg_state == NETREG_UNINITIALIZED) {
1958                 err = register_netdev(dev);
1959                 if (err) {
1960                         pr_warn("%s: register_netdev err=%d\n", __func__, err);
1961                         device_unregister(&np->xbdev->dev);
1962                         return err;
1963                 }
1964         }
1965
1966         /*
1967          * All public and private state should now be sane.  Get
1968          * ready to start sending and receiving packets and give the driver
1969          * domain a kick because we've probably just requeued some
1970          * packets.
1971          */
1972         netif_carrier_on(np->netdev);
1973         for (j = 0; j < num_queues; ++j) {
1974                 queue = &np->queues[j];
1975
1976                 notify_remote_via_irq(queue->tx_irq);
1977                 if (queue->tx_irq != queue->rx_irq)
1978                         notify_remote_via_irq(queue->rx_irq);
1979
1980                 spin_lock_irq(&queue->tx_lock);
1981                 xennet_tx_buf_gc(queue);
1982                 spin_unlock_irq(&queue->tx_lock);
1983
1984                 spin_lock_bh(&queue->rx_lock);
1985                 xennet_alloc_rx_buffers(queue);
1986                 spin_unlock_bh(&queue->rx_lock);
1987         }
1988
1989         return 0;
1990 }
1991
1992 /**
1993  * Callback received when the backend's state changes.
1994  */
1995 static void netback_changed(struct xenbus_device *dev,
1996                             enum xenbus_state backend_state)
1997 {
1998         struct netfront_info *np = dev_get_drvdata(&dev->dev);
1999         struct net_device *netdev = np->netdev;
2000
2001         dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
2002
2003         switch (backend_state) {
2004         case XenbusStateInitialising:
2005         case XenbusStateInitialised:
2006         case XenbusStateReconfiguring:
2007         case XenbusStateReconfigured:
2008                 break;
2009
2010         case XenbusStateUnknown:
2011                 wake_up_all(&module_unload_q);
2012                 break;
2013
2014         case XenbusStateInitWait:
2015                 if (dev->state != XenbusStateInitialising)
2016                         break;
2017                 if (xennet_connect(netdev) != 0)
2018                         break;
2019                 xenbus_switch_state(dev, XenbusStateConnected);
2020                 break;
2021
2022         case XenbusStateConnected:
2023                 netdev_notify_peers(netdev);
2024                 break;
2025
2026         case XenbusStateClosed:
2027                 wake_up_all(&module_unload_q);
2028                 if (dev->state == XenbusStateClosed)
2029                         break;
2030                 /* Missed the backend's CLOSING state -- fallthrough */
2031         case XenbusStateClosing:
2032                 wake_up_all(&module_unload_q);
2033                 xenbus_frontend_closed(dev);
2034                 break;
2035         }
2036 }
2037
2038 static const struct xennet_stat {
2039         char name[ETH_GSTRING_LEN];
2040         u16 offset;
2041 } xennet_stats[] = {
2042         {
2043                 "rx_gso_checksum_fixup",
2044                 offsetof(struct netfront_info, rx_gso_checksum_fixup)
2045         },
2046 };
2047
2048 static int xennet_get_sset_count(struct net_device *dev, int string_set)
2049 {
2050         switch (string_set) {
2051         case ETH_SS_STATS:
2052                 return ARRAY_SIZE(xennet_stats);
2053         default:
2054                 return -EINVAL;
2055         }
2056 }
2057
2058 static void xennet_get_ethtool_stats(struct net_device *dev,
2059                                      struct ethtool_stats *stats, u64 * data)
2060 {
2061         void *np = netdev_priv(dev);
2062         int i;
2063
2064         for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2065                 data[i] = atomic_read((atomic_t *)(np + xennet_stats[i].offset));
2066 }
2067
2068 static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data)
2069 {
2070         int i;
2071
2072         switch (stringset) {
2073         case ETH_SS_STATS:
2074                 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2075                         memcpy(data + i * ETH_GSTRING_LEN,
2076                                xennet_stats[i].name, ETH_GSTRING_LEN);
2077                 break;
2078         }
2079 }
2080
2081 static const struct ethtool_ops xennet_ethtool_ops =
2082 {
2083         .get_link = ethtool_op_get_link,
2084
2085         .get_sset_count = xennet_get_sset_count,
2086         .get_ethtool_stats = xennet_get_ethtool_stats,
2087         .get_strings = xennet_get_strings,
2088 };
2089
2090 #ifdef CONFIG_SYSFS
2091 static ssize_t show_rxbuf(struct device *dev,
2092                           struct device_attribute *attr, char *buf)
2093 {
2094         return sprintf(buf, "%lu\n", NET_RX_RING_SIZE);
2095 }
2096
2097 static ssize_t store_rxbuf(struct device *dev,
2098                            struct device_attribute *attr,
2099                            const char *buf, size_t len)
2100 {
2101         char *endp;
2102         unsigned long target;
2103
2104         if (!capable(CAP_NET_ADMIN))
2105                 return -EPERM;
2106
2107         target = simple_strtoul(buf, &endp, 0);
2108         if (endp == buf)
2109                 return -EBADMSG;
2110
2111         /* rxbuf_min and rxbuf_max are no longer configurable. */
2112
2113         return len;
2114 }
2115
2116 static DEVICE_ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf, store_rxbuf);
2117 static DEVICE_ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf, store_rxbuf);
2118 static DEVICE_ATTR(rxbuf_cur, S_IRUGO, show_rxbuf, NULL);
2119
2120 static struct attribute *xennet_dev_attrs[] = {
2121         &dev_attr_rxbuf_min.attr,
2122         &dev_attr_rxbuf_max.attr,
2123         &dev_attr_rxbuf_cur.attr,
2124         NULL
2125 };
2126
2127 static const struct attribute_group xennet_dev_group = {
2128         .attrs = xennet_dev_attrs
2129 };
2130 #endif /* CONFIG_SYSFS */
2131
2132 static int xennet_remove(struct xenbus_device *dev)
2133 {
2134         struct netfront_info *info = dev_get_drvdata(&dev->dev);
2135
2136         dev_dbg(&dev->dev, "%s\n", dev->nodename);
2137
2138         if (xenbus_read_driver_state(dev->otherend) != XenbusStateClosed) {
2139                 xenbus_switch_state(dev, XenbusStateClosing);
2140                 wait_event(module_unload_q,
2141                            xenbus_read_driver_state(dev->otherend) ==
2142                            XenbusStateClosing ||
2143                            xenbus_read_driver_state(dev->otherend) ==
2144                            XenbusStateUnknown);
2145
2146                 xenbus_switch_state(dev, XenbusStateClosed);
2147                 wait_event(module_unload_q,
2148                            xenbus_read_driver_state(dev->otherend) ==
2149                            XenbusStateClosed ||
2150                            xenbus_read_driver_state(dev->otherend) ==
2151                            XenbusStateUnknown);
2152         }
2153
2154         xennet_disconnect_backend(info);
2155
2156         if (info->netdev->reg_state == NETREG_REGISTERED)
2157                 unregister_netdev(info->netdev);
2158
2159         if (info->queues) {
2160                 rtnl_lock();
2161                 xennet_destroy_queues(info);
2162                 rtnl_unlock();
2163         }
2164         xennet_free_netdev(info->netdev);
2165
2166         return 0;
2167 }
2168
2169 static const struct xenbus_device_id netfront_ids[] = {
2170         { "vif" },
2171         { "" }
2172 };
2173
2174 static struct xenbus_driver netfront_driver = {
2175         .ids = netfront_ids,
2176         .probe = netfront_probe,
2177         .remove = xennet_remove,
2178         .resume = netfront_resume,
2179         .otherend_changed = netback_changed,
2180 };
2181
2182 static int __init netif_init(void)
2183 {
2184         if (!xen_domain())
2185                 return -ENODEV;
2186
2187         if (!xen_has_pv_nic_devices())
2188                 return -ENODEV;
2189
2190         pr_info("Initialising Xen virtual ethernet driver\n");
2191
2192         /* Allow as many queues as there are CPUs inut max. 8 if user has not
2193          * specified a value.
2194          */
2195         if (xennet_max_queues == 0)
2196                 xennet_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
2197                                           num_online_cpus());
2198
2199         return xenbus_register_frontend(&netfront_driver);
2200 }
2201 module_init(netif_init);
2202
2203
2204 static void __exit netif_exit(void)
2205 {
2206         xenbus_unregister_driver(&netfront_driver);
2207 }
2208 module_exit(netif_exit);
2209
2210 MODULE_DESCRIPTION("Xen virtual network device frontend");
2211 MODULE_LICENSE("GPL");
2212 MODULE_ALIAS("xen:vif");
2213 MODULE_ALIAS("xennet");