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 <asm/xen/page.h>
  49 #include <xen/xen.h>
  50 #include <xen/xenbus.h>
  51 #include <xen/events.h>
  52 #include <xen/page.h>
  53 #include <xen/platform_pci.h>
  54 #include <xen/grant_table.h>
  55
  56 #include <xen/interface/io/netif.h>
  57 #include <xen/interface/memory.h>
  58 #include <xen/interface/grant_table.h>
  59
  60 /* Module parameters */
  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, PAGE_SIZE)
  79 #define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
  80 #define TX_MAX_TARGET min_t(int, NET_TX_RING_SIZE, 256)
  81
  82 /* Queue name is interface name with "-qNNN" appended */
  83 #define QUEUE_NAME_SIZE (IFNAMSIZ + 6)
  84
  85 /* IRQ name is queue name with "-tx" or "-rx" appended */
  86 #define IRQ_NAME_SIZE (QUEUE_NAME_SIZE + 3)
  87
  88 struct netfront_stats {
  89         u64                     rx_packets;
  90         u64                     tx_packets;
  91         u64                     rx_bytes;
  92         u64                     tx_bytes;
  93         struct u64_stats_sync   syncp;
  94 };
  95
  96 struct netfront_info;
  97
  98 struct netfront_queue {
  99         unsigned int id; /* Queue ID, 0-based */
 100         char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
 101         struct netfront_info *info;
 102
 103         struct napi_struct napi;
 104
 105         /* Split event channels support, tx_* == rx_* when using
 106          * single event channel.
 107          */
 108         unsigned int tx_evtchn, rx_evtchn;
 109         unsigned int tx_irq, rx_irq;
 110         /* Only used when split event channels support is enabled */
 111         char tx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-tx */
 112         char rx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-rx */
 113
 114         spinlock_t   tx_lock;
 115         struct xen_netif_tx_front_ring tx;
 116         int tx_ring_ref;
 117
 118         /*
 119          * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
 120          * are linked from tx_skb_freelist through skb_entry.link.
 121          *
 122          *  NB. Freelist index entries are always going to be less than
 123          *  PAGE_OFFSET, whereas pointers to skbs will always be equal or
 124          *  greater than PAGE_OFFSET: we use this property to distinguish
 125          *  them.
 126          */
 127         union skb_entry {
 128                 struct sk_buff *skb;
 129                 unsigned long link;
 130         } tx_skbs[NET_TX_RING_SIZE];
 131         grant_ref_t gref_tx_head;
 132         grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
 133         struct page *grant_tx_page[NET_TX_RING_SIZE];
 134         unsigned tx_skb_freelist;
 135
 136         spinlock_t   rx_lock ____cacheline_aligned_in_smp;
 137         struct xen_netif_rx_front_ring rx;
 138         int rx_ring_ref;
 139
 140         /* Receive-ring batched refills. */
 141 #define RX_MIN_TARGET 8
 142 #define RX_DFL_MIN_TARGET 64
 143 #define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
 144         unsigned rx_min_target, rx_max_target, rx_target;
 145         struct sk_buff_head rx_batch;
 146
 147         struct timer_list rx_refill_timer;
 148
 149         struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
 150         grant_ref_t gref_rx_head;
 151         grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
 152
 153         unsigned long rx_pfn_array[NET_RX_RING_SIZE];
 154         struct multicall_entry rx_mcl[NET_RX_RING_SIZE+1];
 155         struct mmu_update rx_mmu[NET_RX_RING_SIZE];
 156 };
 157
 158 struct netfront_info {
 159         struct list_head list;
 160         struct net_device *netdev;
 161
 162         struct xenbus_device *xbdev;
 163
 164         /* Multi-queue support */
 165         struct netfront_queue *queues;
 166
 167         /* Statistics */
 168         struct netfront_stats __percpu *stats;
 169
 170         atomic_t rx_gso_checksum_fixup;
 171 };
 172
 173 struct netfront_rx_info {
 174         struct xen_netif_rx_response rx;
 175         struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
 176 };
 177
 178 static void skb_entry_set_link(union skb_entry *list, unsigned short id)
 179 {
 180         list->link = id;
 181 }
 182
 183 static int skb_entry_is_link(const union skb_entry *list)
 184 {
 185         BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link));
 186         return (unsigned long)list->skb < PAGE_OFFSET;
 187 }
 188
 189 /*
 190  * Access macros for acquiring freeing slots in tx_skbs[].
 191  */
 192
 193 static void add_id_to_freelist(unsigned *head, union skb_entry *list,
 194                                unsigned short id)
 195 {
 196         skb_entry_set_link(&list[id], *head);
 197         *head = id;
 198 }
 199
 200 static unsigned short get_id_from_freelist(unsigned *head,
 201                                            union skb_entry *list)
 202 {
 203         unsigned int id = *head;
 204         *head = list[id].link;
 205         return id;
 206 }
 207
 208 static int xennet_rxidx(RING_IDX idx)
 209 {
 210         return idx & (NET_RX_RING_SIZE - 1);
 211 }
 212
 213 static struct sk_buff *xennet_get_rx_skb(struct netfront_queue *queue,
 214                                          RING_IDX ri)
 215 {
 216         int i = xennet_rxidx(ri);
 217         struct sk_buff *skb = queue->rx_skbs[i];
 218         queue->rx_skbs[i] = NULL;
 219         return skb;
 220 }
 221
 222 static grant_ref_t xennet_get_rx_ref(struct netfront_queue *queue,
 223                                             RING_IDX ri)
 224 {
 225         int i = xennet_rxidx(ri);
 226         grant_ref_t ref = queue->grant_rx_ref[i];
 227         queue->grant_rx_ref[i] = GRANT_INVALID_REF;
 228         return ref;
 229 }
 230
 231 #ifdef CONFIG_SYSFS
 232 static int xennet_sysfs_addif(struct net_device *netdev);
 233 static void xennet_sysfs_delif(struct net_device *netdev);
 234 #else /* !CONFIG_SYSFS */
 235 #define xennet_sysfs_addif(dev) (0)
 236 #define xennet_sysfs_delif(dev) do { } while (0)
 237 #endif
 238
 239 static bool xennet_can_sg(struct net_device *dev)
 240 {
 241         return dev->features & NETIF_F_SG;
 242 }
 243
 244
 245 static void rx_refill_timeout(unsigned long data)
 246 {
 247         struct netfront_queue *queue = (struct netfront_queue *)data;
 248         napi_schedule(&queue->napi);
 249 }
 250
 251 static int netfront_tx_slot_available(struct netfront_queue *queue)
 252 {
 253         return (queue->tx.req_prod_pvt - queue->tx.rsp_cons) <
 254                 (TX_MAX_TARGET - MAX_SKB_FRAGS - 2);
 255 }
 256
 257 static void xennet_maybe_wake_tx(struct netfront_queue *queue)
 258 {
 259         struct net_device *dev = queue->info->netdev;
 260         struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, queue->id);
 261
 262         if (unlikely(netif_tx_queue_stopped(dev_queue)) &&
 263             netfront_tx_slot_available(queue) &&
 264             likely(netif_running(dev)))
 265                 netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id));
 266 }
 267
 268 static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
 269 {
 270         unsigned short id;
 271         struct sk_buff *skb;
 272         struct page *page;
 273         int i, batch_target, notify;
 274         RING_IDX req_prod = queue->rx.req_prod_pvt;
 275         grant_ref_t ref;
 276         unsigned long pfn;
 277         void *vaddr;
 278         struct xen_netif_rx_request *req;
 279
 280         if (unlikely(!netif_carrier_ok(queue->info->netdev)))
 281                 return;
 282
 283         /*
 284          * Allocate skbuffs greedily, even though we batch updates to the
 285          * receive ring. This creates a less bursty demand on the memory
 286          * allocator, so should reduce the chance of failed allocation requests
 287          * both for ourself and for other kernel subsystems.
 288          */
 289         batch_target = queue->rx_target - (req_prod - queue->rx.rsp_cons);
 290         for (i = skb_queue_len(&queue->rx_batch); i < batch_target; i++) {
 291                 skb = __netdev_alloc_skb(queue->info->netdev,
 292                                          RX_COPY_THRESHOLD + NET_IP_ALIGN,
 293                                          GFP_ATOMIC | __GFP_NOWARN);
 294                 if (unlikely(!skb))
 295                         goto no_skb;
 296
 297                 /* Align ip header to a 16 bytes boundary */
 298                 skb_reserve(skb, NET_IP_ALIGN);
 299
 300                 page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 301                 if (!page) {
 302                         kfree_skb(skb);
 303 no_skb:
 304                         /* Could not allocate any skbuffs. Try again later. */
 305                         mod_timer(&queue->rx_refill_timer,
 306                                   jiffies + (HZ/10));
 307
 308                         /* Any skbuffs queued for refill? Force them out. */
 309                         if (i != 0)
 310                                 goto refill;
 311                         break;
 312                 }
 313
 314                 skb_add_rx_frag(skb, 0, page, 0, 0, PAGE_SIZE);
 315                 __skb_queue_tail(&queue->rx_batch, skb);
 316         }
 317
 318         /* Is the batch large enough to be worthwhile? */
 319         if (i < (queue->rx_target/2)) {
 320                 if (req_prod > queue->rx.sring->req_prod)
 321                         goto push;
 322                 return;
 323         }
 324
 325         /* Adjust our fill target if we risked running out of buffers. */
 326         if (((req_prod - queue->rx.sring->rsp_prod) < (queue->rx_target / 4)) &&
 327             ((queue->rx_target *= 2) > queue->rx_max_target))
 328                 queue->rx_target = queue->rx_max_target;
 329
 330  refill:
 331         for (i = 0; ; i++) {
 332                 skb = __skb_dequeue(&queue->rx_batch);
 333                 if (skb == NULL)
 334                         break;
 335
 336                 skb->dev = queue->info->netdev;
 337
 338                 id = xennet_rxidx(req_prod + i);
 339
 340                 BUG_ON(queue->rx_skbs[id]);
 341                 queue->rx_skbs[id] = skb;
 342
 343                 ref = gnttab_claim_grant_reference(&queue->gref_rx_head);
 344                 BUG_ON((signed short)ref < 0);
 345                 queue->grant_rx_ref[id] = ref;
 346
 347                 pfn = page_to_pfn(skb_frag_page(&skb_shinfo(skb)->frags[0]));
 348                 vaddr = page_address(skb_frag_page(&skb_shinfo(skb)->frags[0]));
 349
 350                 req = RING_GET_REQUEST(&queue->rx, req_prod + i);
 351                 gnttab_grant_foreign_access_ref(ref,
 352                                                 queue->info->xbdev->otherend_id,
 353                                                 pfn_to_mfn(pfn),
 354                                                 0);
 355
 356                 req->id = id;
 357                 req->gref = ref;
 358         }
 359
 360         wmb();          /* barrier so backend seens requests */
 361
 362         /* Above is a suitable barrier to ensure backend will see requests. */
 363         queue->rx.req_prod_pvt = req_prod + i;
 364  push:
 365         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->rx, notify);
 366         if (notify)
 367                 notify_remote_via_irq(queue->rx_irq);
 368 }
 369
 370 static int xennet_open(struct net_device *dev)
 371 {
 372         struct netfront_info *np = netdev_priv(dev);
 373         unsigned int num_queues = dev->real_num_tx_queues;
 374         unsigned int i = 0;
 375         struct netfront_queue *queue = NULL;
 376
 377         for (i = 0; i < num_queues; ++i) {
 378                 queue = &np->queues[i];
 379                 napi_enable(&queue->napi);
 380
 381                 spin_lock_bh(&queue->rx_lock);
 382                 if (netif_carrier_ok(dev)) {
 383                         xennet_alloc_rx_buffers(queue);
 384                         queue->rx.sring->rsp_event = queue->rx.rsp_cons + 1;
 385                         if (RING_HAS_UNCONSUMED_RESPONSES(&queue->rx))
 386                                 napi_schedule(&queue->napi);
 387                 }
 388                 spin_unlock_bh(&queue->rx_lock);
 389         }
 390
 391         netif_tx_start_all_queues(dev);
 392
 393         return 0;
 394 }
 395
 396 static void xennet_tx_buf_gc(struct netfront_queue *queue)
 397 {
 398         RING_IDX cons, prod;
 399         unsigned short id;
 400         struct sk_buff *skb;
 401
 402         BUG_ON(!netif_carrier_ok(queue->info->netdev));
 403
 404         do {
 405                 prod = queue->tx.sring->rsp_prod;
 406                 rmb(); /* Ensure we see responses up to 'rp'. */
 407
 408                 for (cons = queue->tx.rsp_cons; cons != prod; cons++) {
 409                         struct xen_netif_tx_response *txrsp;
 410
 411                         txrsp = RING_GET_RESPONSE(&queue->tx, cons);
 412                         if (txrsp->status == XEN_NETIF_RSP_NULL)
 413                                 continue;
 414
 415                         id  = txrsp->id;
 416                         skb = queue->tx_skbs[id].skb;
 417                         if (unlikely(gnttab_query_foreign_access(
 418                                 queue->grant_tx_ref[id]) != 0)) {
 419                                 pr_alert("%s: warning -- grant still in use by backend domain\n",
 420                                          __func__);
 421                                 BUG();
 422                         }
 423                         gnttab_end_foreign_access_ref(
 424                                 queue->grant_tx_ref[id], GNTMAP_readonly);
 425                         gnttab_release_grant_reference(
 426                                 &queue->gref_tx_head, queue->grant_tx_ref[id]);
 427                         queue->grant_tx_ref[id] = GRANT_INVALID_REF;
 428                         queue->grant_tx_page[id] = NULL;
 429                         add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, id);
 430                         dev_kfree_skb_irq(skb);
 431                 }
 432
 433                 queue->tx.rsp_cons = prod;
 434
 435                 /*
 436                  * Set a new event, then check for race with update of tx_cons.
 437                  * Note that it is essential to schedule a callback, no matter
 438                  * how few buffers are pending. Even if there is space in the
 439                  * transmit ring, higher layers may be blocked because too much
 440                  * data is outstanding: in such cases notification from Xen is
 441                  * likely to be the only kick that we'll get.
 442                  */
 443                 queue->tx.sring->rsp_event =
 444                         prod + ((queue->tx.sring->req_prod - prod) >> 1) + 1;
 445                 mb();           /* update shared area */
 446         } while ((cons == prod) && (prod != queue->tx.sring->rsp_prod));
 447
 448         xennet_maybe_wake_tx(queue);
 449 }
 450
 451 static void xennet_make_frags(struct sk_buff *skb, struct netfront_queue *queue,
 452                               struct xen_netif_tx_request *tx)
 453 {
 454         char *data = skb->data;
 455         unsigned long mfn;
 456         RING_IDX prod = queue->tx.req_prod_pvt;
 457         int frags = skb_shinfo(skb)->nr_frags;
 458         unsigned int offset = offset_in_page(data);
 459         unsigned int len = skb_headlen(skb);
 460         unsigned int id;
 461         grant_ref_t ref;
 462         int i;
 463
 464         /* While the header overlaps a page boundary (including being
 465            larger than a page), split it it into page-sized chunks. */
 466         while (len > PAGE_SIZE - offset) {
 467                 tx->size = PAGE_SIZE - offset;
 468                 tx->flags |= XEN_NETTXF_more_data;
 469                 len -= tx->size;
 470                 data += tx->size;
 471                 offset = 0;
 472
 473                 id = get_id_from_freelist(&queue->tx_skb_freelist, queue->tx_skbs);
 474                 queue->tx_skbs[id].skb = skb_get(skb);
 475                 tx = RING_GET_REQUEST(&queue->tx, prod++);
 476                 tx->id = id;
 477                 ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
 478                 BUG_ON((signed short)ref < 0);
 479
 480                 mfn = virt_to_mfn(data);
 481                 gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,
 482                                                 mfn, GNTMAP_readonly);
 483
 484                 queue->grant_tx_page[id] = virt_to_page(data);
 485                 tx->gref = queue->grant_tx_ref[id] = ref;
 486                 tx->offset = offset;
 487                 tx->size = len;
 488                 tx->flags = 0;
 489         }
 490
 491         /* Grant backend access to each skb fragment page. */
 492         for (i = 0; i < frags; i++) {
 493                 skb_frag_t *frag = skb_shinfo(skb)->frags + i;
 494                 struct page *page = skb_frag_page(frag);
 495
 496                 len = skb_frag_size(frag);
 497                 offset = frag->page_offset;
 498
 499                 /* Skip unused frames from start of page */
 500                 page += offset >> PAGE_SHIFT;
 501                 offset &= ~PAGE_MASK;
 502
 503                 while (len > 0) {
 504                         unsigned long bytes;
 505
 506                         bytes = PAGE_SIZE - offset;
 507                         if (bytes > len)
 508                                 bytes = len;
 509
 510                         tx->flags |= XEN_NETTXF_more_data;
 511
 512                         id = get_id_from_freelist(&queue->tx_skb_freelist,
 513                                                   queue->tx_skbs);
 514                         queue->tx_skbs[id].skb = skb_get(skb);
 515                         tx = RING_GET_REQUEST(&queue->tx, prod++);
 516                         tx->id = id;
 517                         ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
 518                         BUG_ON((signed short)ref < 0);
 519
 520                         mfn = pfn_to_mfn(page_to_pfn(page));
 521                         gnttab_grant_foreign_access_ref(ref,
 522                                                         queue->info->xbdev->otherend_id,
 523                                                         mfn, GNTMAP_readonly);
 524
 525                         queue->grant_tx_page[id] = page;
 526                         tx->gref = queue->grant_tx_ref[id] = ref;
 527                         tx->offset = offset;
 528                         tx->size = bytes;
 529                         tx->flags = 0;
 530
 531                         offset += bytes;
 532                         len -= bytes;
 533
 534                         /* Next frame */
 535                         if (offset == PAGE_SIZE && len) {
 536                                 BUG_ON(!PageCompound(page));
 537                                 page++;
 538                                 offset = 0;
 539                         }
 540                 }
 541         }
 542
 543         queue->tx.req_prod_pvt = prod;
 544 }
 545
 546 /*
 547  * Count how many ring slots are required to send the frags of this
 548  * skb. Each frag might be a compound page.
 549  */
 550 static int xennet_count_skb_frag_slots(struct sk_buff *skb)
 551 {
 552         int i, frags = skb_shinfo(skb)->nr_frags;
 553         int pages = 0;
 554
 555         for (i = 0; i < frags; i++) {
 556                 skb_frag_t *frag = skb_shinfo(skb)->frags + i;
 557                 unsigned long size = skb_frag_size(frag);
 558                 unsigned long offset = frag->page_offset;
 559
 560                 /* Skip unused frames from start of page */
 561                 offset &= ~PAGE_MASK;
 562
 563                 pages += PFN_UP(offset + size);
 564         }
 565
 566         return pages;
 567 }
 568
 569 static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb,
 570                                void *accel_priv, select_queue_fallback_t fallback)
 571 {
 572         unsigned int num_queues = dev->real_num_tx_queues;
 573         u32 hash;
 574         u16 queue_idx;
 575
 576         /* First, check if there is only one queue */
 577         if (num_queues == 1) {
 578                 queue_idx = 0;
 579         } else {
 580                 hash = skb_get_hash(skb);
 581                 queue_idx = hash % num_queues;
 582         }
 583
 584         return queue_idx;
 585 }
 586
 587 static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 588 {
 589         unsigned short id;
 590         struct netfront_info *np = netdev_priv(dev);
 591         struct netfront_stats *stats = this_cpu_ptr(np->stats);
 592         struct xen_netif_tx_request *tx;
 593         char *data = skb->data;
 594         RING_IDX i;
 595         grant_ref_t ref;
 596         unsigned long mfn;
 597         int notify;
 598         int slots;
 599         unsigned int offset = offset_in_page(data);
 600         unsigned int len = skb_headlen(skb);
 601         unsigned long flags;
 602         struct netfront_queue *queue = NULL;
 603         unsigned int num_queues = dev->real_num_tx_queues;
 604         u16 queue_index;
 605
 606         /* Drop the packet if no queues are set up */
 607         if (num_queues < 1)
 608                 goto drop;
 609         /* Determine which queue to transmit this SKB on */
 610         queue_index = skb_get_queue_mapping(skb);
 611         queue = &np->queues[queue_index];
 612
 613         /* If skb->len is too big for wire format, drop skb and alert
 614          * user about misconfiguration.
 615          */
 616         if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) {
 617                 net_alert_ratelimited(
 618                         "xennet: skb->len = %u, too big for wire format\n",
 619                         skb->len);
 620                 goto drop;
 621         }
 622
 623         slots = DIV_ROUND_UP(offset + len, PAGE_SIZE) +
 624                 xennet_count_skb_frag_slots(skb);
 625         if (unlikely(slots > MAX_SKB_FRAGS + 1)) {
 626                 net_dbg_ratelimited("xennet: skb rides the rocket: %d slots, %d bytes\n",
 627                                     slots, skb->len);
 628                 if (skb_linearize(skb))
 629                         goto drop;
 630         }
 631
 632         spin_lock_irqsave(&queue->tx_lock, flags);
 633
 634         if (unlikely(!netif_carrier_ok(dev) ||
 635                      (slots > 1 && !xennet_can_sg(dev)) ||
 636                      netif_needs_gso(dev, skb, netif_skb_features(skb)))) {
 637                 spin_unlock_irqrestore(&queue->tx_lock, flags);
 638                 goto drop;
 639         }
 640
 641         i = queue->tx.req_prod_pvt;
 642
 643         id = get_id_from_freelist(&queue->tx_skb_freelist, queue->tx_skbs);
 644         queue->tx_skbs[id].skb = skb;
 645
 646         tx = RING_GET_REQUEST(&queue->tx, i);
 647
 648         tx->id   = id;
 649         ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
 650         BUG_ON((signed short)ref < 0);
 651         mfn = virt_to_mfn(data);
 652         gnttab_grant_foreign_access_ref(
 653                 ref, queue->info->xbdev->otherend_id, mfn, GNTMAP_readonly);
 654         queue->grant_tx_page[id] = virt_to_page(data);
 655         tx->gref = queue->grant_tx_ref[id] = ref;
 656         tx->offset = offset;
 657         tx->size = len;
 658
 659         tx->flags = 0;
 660         if (skb->ip_summed == CHECKSUM_PARTIAL)
 661                 /* local packet? */
 662                 tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
 663         else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
 664                 /* remote but checksummed. */
 665                 tx->flags |= XEN_NETTXF_data_validated;
 666
 667         if (skb_shinfo(skb)->gso_size) {
 668                 struct xen_netif_extra_info *gso;
 669
 670                 gso = (struct xen_netif_extra_info *)
 671                         RING_GET_REQUEST(&queue->tx, ++i);
 672
 673                 tx->flags |= XEN_NETTXF_extra_info;
 674
 675                 gso->u.gso.size = skb_shinfo(skb)->gso_size;
 676                 gso->u.gso.type = (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) ?
 677                         XEN_NETIF_GSO_TYPE_TCPV6 :
 678                         XEN_NETIF_GSO_TYPE_TCPV4;
 679                 gso->u.gso.pad = 0;
 680                 gso->u.gso.features = 0;
 681
 682                 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
 683                 gso->flags = 0;
 684         }
 685
 686         queue->tx.req_prod_pvt = i + 1;
 687
 688         xennet_make_frags(skb, queue, tx);
 689         tx->size = skb->len;
 690
 691         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
 692         if (notify)
 693                 notify_remote_via_irq(queue->tx_irq);
 694
 695         u64_stats_update_begin(&stats->syncp);
 696         stats->tx_bytes += skb->len;
 697         stats->tx_packets++;
 698         u64_stats_update_end(&stats->syncp);
 699
 700         /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
 701         xennet_tx_buf_gc(queue);
 702
 703         if (!netfront_tx_slot_available(queue))
 704                 netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
 705
 706         spin_unlock_irqrestore(&queue->tx_lock, flags);
 707
 708         return NETDEV_TX_OK;
 709
 710  drop:
 711         dev->stats.tx_dropped++;
 712         dev_kfree_skb_any(skb);
 713         return NETDEV_TX_OK;
 714 }
 715
 716 static int xennet_close(struct net_device *dev)
 717 {
 718         struct netfront_info *np = netdev_priv(dev);
 719         unsigned int num_queues = dev->real_num_tx_queues;
 720         unsigned int i;
 721         struct netfront_queue *queue;
 722         netif_tx_stop_all_queues(np->netdev);
 723         for (i = 0; i < num_queues; ++i) {
 724                 queue = &np->queues[i];
 725                 napi_disable(&queue->napi);
 726         }
 727         return 0;
 728 }
 729
 730 static void xennet_move_rx_slot(struct netfront_queue *queue, struct sk_buff *skb,
 731                                 grant_ref_t ref)
 732 {
 733         int new = xennet_rxidx(queue->rx.req_prod_pvt);
 734
 735         BUG_ON(queue->rx_skbs[new]);
 736         queue->rx_skbs[new] = skb;
 737         queue->grant_rx_ref[new] = ref;
 738         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->id = new;
 739         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->gref = ref;
 740         queue->rx.req_prod_pvt++;
 741 }
 742
 743 static int xennet_get_extras(struct netfront_queue *queue,
 744                              struct xen_netif_extra_info *extras,
 745                              RING_IDX rp)
 746
 747 {
 748         struct xen_netif_extra_info *extra;
 749         struct device *dev = &queue->info->netdev->dev;
 750         RING_IDX cons = queue->rx.rsp_cons;
 751         int err = 0;
 752
 753         do {
 754                 struct sk_buff *skb;
 755                 grant_ref_t ref;
 756
 757                 if (unlikely(cons + 1 == rp)) {
 758                         if (net_ratelimit())
 759                                 dev_warn(dev, "Missing extra info\n");
 760                         err = -EBADR;
 761                         break;
 762                 }
 763
 764                 extra = (struct xen_netif_extra_info *)
 765                         RING_GET_RESPONSE(&queue->rx, ++cons);
 766
 767                 if (unlikely(!extra->type ||
 768                              extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 769                         if (net_ratelimit())
 770                                 dev_warn(dev, "Invalid extra type: %d\n",
 771                                         extra->type);
 772                         err = -EINVAL;
 773                 } else {
 774                         memcpy(&extras[extra->type - 1], extra,
 775                                sizeof(*extra));
 776                 }
 777
 778                 skb = xennet_get_rx_skb(queue, cons);
 779                 ref = xennet_get_rx_ref(queue, cons);
 780                 xennet_move_rx_slot(queue, skb, ref);
 781         } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
 782
 783         queue->rx.rsp_cons = cons;
 784         return err;
 785 }
 786
 787 static int xennet_get_responses(struct netfront_queue *queue,
 788                                 struct netfront_rx_info *rinfo, RING_IDX rp,
 789                                 struct sk_buff_head *list)
 790 {
 791         struct xen_netif_rx_response *rx = &rinfo->rx;
 792         struct xen_netif_extra_info *extras = rinfo->extras;
 793         struct device *dev = &queue->info->netdev->dev;
 794         RING_IDX cons = queue->rx.rsp_cons;
 795         struct sk_buff *skb = xennet_get_rx_skb(queue, cons);
 796         grant_ref_t ref = xennet_get_rx_ref(queue, cons);
 797         int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD);
 798         int slots = 1;
 799         int err = 0;
 800         unsigned long ret;
 801
 802         if (rx->flags & XEN_NETRXF_extra_info) {
 803                 err = xennet_get_extras(queue, extras, rp);
 804                 cons = queue->rx.rsp_cons;
 805         }
 806
 807         for (;;) {
 808                 if (unlikely(rx->status < 0 ||
 809                              rx->offset + rx->status > PAGE_SIZE)) {
 810                         if (net_ratelimit())
 811                                 dev_warn(dev, "rx->offset: %x, size: %u\n",
 812                                          rx->offset, rx->status);
 813                         xennet_move_rx_slot(queue, skb, ref);
 814                         err = -EINVAL;
 815                         goto next;
 816                 }
 817
 818                 /*
 819                  * This definitely indicates a bug, either in this driver or in
 820                  * the backend driver. In future this should flag the bad
 821                  * situation to the system controller to reboot the backend.
 822                  */
 823                 if (ref == GRANT_INVALID_REF) {
 824                         if (net_ratelimit())
 825                                 dev_warn(dev, "Bad rx response id %d.\n",
 826                                          rx->id);
 827                         err = -EINVAL;
 828                         goto next;
 829                 }
 830
 831                 ret = gnttab_end_foreign_access_ref(ref, 0);
 832                 BUG_ON(!ret);
 833
 834                 gnttab_release_grant_reference(&queue->gref_rx_head, ref);
 835
 836                 __skb_queue_tail(list, skb);
 837
 838 next:
 839                 if (!(rx->flags & XEN_NETRXF_more_data))
 840                         break;
 841
 842                 if (cons + slots == rp) {
 843                         if (net_ratelimit())
 844                                 dev_warn(dev, "Need more slots\n");
 845                         err = -ENOENT;
 846                         break;
 847                 }
 848
 849                 rx = RING_GET_RESPONSE(&queue->rx, cons + slots);
 850                 skb = xennet_get_rx_skb(queue, cons + slots);
 851                 ref = xennet_get_rx_ref(queue, cons + slots);
 852                 slots++;
 853         }
 854
 855         if (unlikely(slots > max)) {
 856                 if (net_ratelimit())
 857                         dev_warn(dev, "Too many slots\n");
 858                 err = -E2BIG;
 859         }
 860
 861         if (unlikely(err))
 862                 queue->rx.rsp_cons = cons + slots;
 863
 864         return err;
 865 }
 866
 867 static int xennet_set_skb_gso(struct sk_buff *skb,
 868                               struct xen_netif_extra_info *gso)
 869 {
 870         if (!gso->u.gso.size) {
 871                 if (net_ratelimit())
 872                         pr_warn("GSO size must not be zero\n");
 873                 return -EINVAL;
 874         }
 875
 876         if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4 &&
 877             gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV6) {
 878                 if (net_ratelimit())
 879                         pr_warn("Bad GSO type %d\n", gso->u.gso.type);
 880                 return -EINVAL;
 881         }
 882
 883         skb_shinfo(skb)->gso_size = gso->u.gso.size;
 884         skb_shinfo(skb)->gso_type =
 885                 (gso->u.gso.type == XEN_NETIF_GSO_TYPE_TCPV4) ?
 886                 SKB_GSO_TCPV4 :
 887                 SKB_GSO_TCPV6;
 888
 889         /* Header must be checked, and gso_segs computed. */
 890         skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 891         skb_shinfo(skb)->gso_segs = 0;
 892
 893         return 0;
 894 }
 895
 896 static RING_IDX xennet_fill_frags(struct netfront_queue *queue,
 897                                   struct sk_buff *skb,
 898                                   struct sk_buff_head *list)
 899 {
 900         struct skb_shared_info *shinfo = skb_shinfo(skb);
 901         RING_IDX cons = queue->rx.rsp_cons;
 902         struct sk_buff *nskb;
 903
 904         while ((nskb = __skb_dequeue(list))) {
 905                 struct xen_netif_rx_response *rx =
 906                         RING_GET_RESPONSE(&queue->rx, ++cons);
 907                 skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0];
 908
 909                 if (shinfo->nr_frags == MAX_SKB_FRAGS) {
 910                         unsigned int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 911
 912                         BUG_ON(pull_to <= skb_headlen(skb));
 913                         __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
 914                 }
 915                 BUG_ON(shinfo->nr_frags >= MAX_SKB_FRAGS);
 916
 917                 skb_add_rx_frag(skb, shinfo->nr_frags, skb_frag_page(nfrag),
 918                                 rx->offset, rx->status, PAGE_SIZE);
 919
 920                 skb_shinfo(nskb)->nr_frags = 0;
 921                 kfree_skb(nskb);
 922         }
 923
 924         return cons;
 925 }
 926
 927 static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
 928 {
 929         bool recalculate_partial_csum = false;
 930
 931         /*
 932          * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 933          * peers can fail to set NETRXF_csum_blank when sending a GSO
 934          * frame. In this case force the SKB to CHECKSUM_PARTIAL and
 935          * recalculate the partial checksum.
 936          */
 937         if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
 938                 struct netfront_info *np = netdev_priv(dev);
 939                 atomic_inc(&np->rx_gso_checksum_fixup);
 940                 skb->ip_summed = CHECKSUM_PARTIAL;
 941                 recalculate_partial_csum = true;
 942         }
 943
 944         /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
 945         if (skb->ip_summed != CHECKSUM_PARTIAL)
 946                 return 0;
 947
 948         return skb_checksum_setup(skb, recalculate_partial_csum);
 949 }
 950
 951 static int handle_incoming_queue(struct netfront_queue *queue,
 952                                  struct sk_buff_head *rxq)
 953 {
 954         struct netfront_stats *stats = this_cpu_ptr(queue->info->stats);
 955         int packets_dropped = 0;
 956         struct sk_buff *skb;
 957
 958         while ((skb = __skb_dequeue(rxq)) != NULL) {
 959                 int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 960
 961                 if (pull_to > skb_headlen(skb))
 962                         __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
 963
 964                 /* Ethernet work: Delayed to here as it peeks the header. */
 965                 skb->protocol = eth_type_trans(skb, queue->info->netdev);
 966                 skb_reset_network_header(skb);
 967
 968                 if (checksum_setup(queue->info->netdev, skb)) {
 969                         kfree_skb(skb);
 970                         packets_dropped++;
 971                         queue->info->netdev->stats.rx_errors++;
 972                         continue;
 973                 }
 974
 975                 u64_stats_update_begin(&stats->syncp);
 976                 stats->rx_packets++;
 977                 stats->rx_bytes += skb->len;
 978                 u64_stats_update_end(&stats->syncp);
 979
 980                 /* Pass it up. */
 981                 napi_gro_receive(&queue->napi, skb);
 982         }
 983
 984         return packets_dropped;
 985 }
 986
 987 static int xennet_poll(struct napi_struct *napi, int budget)
 988 {
 989         struct netfront_queue *queue = container_of(napi, struct netfront_queue, napi);
 990         struct net_device *dev = queue->info->netdev;
 991         struct sk_buff *skb;
 992         struct netfront_rx_info rinfo;
 993         struct xen_netif_rx_response *rx = &rinfo.rx;
 994         struct xen_netif_extra_info *extras = rinfo.extras;
 995         RING_IDX i, rp;
 996         int work_done;
 997         struct sk_buff_head rxq;
 998         struct sk_buff_head errq;
 999         struct sk_buff_head tmpq;
1000         unsigned long flags;
1001         int err;
1002
1003         spin_lock(&queue->rx_lock);
1004
1005         skb_queue_head_init(&rxq);
1006         skb_queue_head_init(&errq);
1007         skb_queue_head_init(&tmpq);
1008
1009         rp = queue->rx.sring->rsp_prod;
1010         rmb(); /* Ensure we see queued responses up to 'rp'. */
1011
1012         i = queue->rx.rsp_cons;
1013         work_done = 0;
1014         while ((i != rp) && (work_done < budget)) {
1015                 memcpy(rx, RING_GET_RESPONSE(&queue->rx, i), sizeof(*rx));
1016                 memset(extras, 0, sizeof(rinfo.extras));
1017
1018                 err = xennet_get_responses(queue, &rinfo, rp, &tmpq);
1019
1020                 if (unlikely(err)) {
1021 err:
1022                         while ((skb = __skb_dequeue(&tmpq)))
1023                                 __skb_queue_tail(&errq, skb);
1024                         dev->stats.rx_errors++;
1025                         i = queue->rx.rsp_cons;
1026                         continue;
1027                 }
1028
1029                 skb = __skb_dequeue(&tmpq);
1030
1031                 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1032                         struct xen_netif_extra_info *gso;
1033                         gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1034
1035                         if (unlikely(xennet_set_skb_gso(skb, gso))) {
1036                                 __skb_queue_head(&tmpq, skb);
1037                                 queue->rx.rsp_cons += skb_queue_len(&tmpq);
1038                                 goto err;
1039                         }
1040                 }
1041
1042                 NETFRONT_SKB_CB(skb)->pull_to = rx->status;
1043                 if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD)
1044                         NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD;
1045
1046                 skb_shinfo(skb)->frags[0].page_offset = rx->offset;
1047                 skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status);
1048                 skb->data_len = rx->status;
1049                 skb->len += rx->status;
1050
1051                 i = xennet_fill_frags(queue, skb, &tmpq);
1052
1053                 if (rx->flags & XEN_NETRXF_csum_blank)
1054                         skb->ip_summed = CHECKSUM_PARTIAL;
1055                 else if (rx->flags & XEN_NETRXF_data_validated)
1056                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1057
1058                 __skb_queue_tail(&rxq, skb);
1059
1060                 queue->rx.rsp_cons = ++i;
1061                 work_done++;
1062         }
1063
1064         __skb_queue_purge(&errq);
1065
1066         work_done -= handle_incoming_queue(queue, &rxq);
1067
1068         /* If we get a callback with very few responses, reduce fill target. */
1069         /* NB. Note exponential increase, linear decrease. */
1070         if (((queue->rx.req_prod_pvt - queue->rx.sring->rsp_prod) >
1071              ((3*queue->rx_target) / 4)) &&
1072             (--queue->rx_target < queue->rx_min_target))
1073                 queue->rx_target = queue->rx_min_target;
1074
1075         xennet_alloc_rx_buffers(queue);
1076
1077         if (work_done < budget) {
1078                 int more_to_do = 0;
1079
1080                 napi_gro_flush(napi, false);
1081
1082                 local_irq_save(flags);
1083
1084                 RING_FINAL_CHECK_FOR_RESPONSES(&queue->rx, more_to_do);
1085                 if (!more_to_do)
1086                         __napi_complete(napi);
1087
1088                 local_irq_restore(flags);
1089         }
1090
1091         spin_unlock(&queue->rx_lock);
1092
1093         return work_done;
1094 }
1095
1096 static int xennet_change_mtu(struct net_device *dev, int mtu)
1097 {
1098         int max = xennet_can_sg(dev) ?
1099                 XEN_NETIF_MAX_TX_SIZE - MAX_TCP_HEADER : ETH_DATA_LEN;
1100
1101         if (mtu > max)
1102                 return -EINVAL;
1103         dev->mtu = mtu;
1104         return 0;
1105 }
1106
1107 static struct rtnl_link_stats64 *xennet_get_stats64(struct net_device *dev,
1108                                                     struct rtnl_link_stats64 *tot)
1109 {
1110         struct netfront_info *np = netdev_priv(dev);
1111         int cpu;
1112
1113         for_each_possible_cpu(cpu) {
1114                 struct netfront_stats *stats = per_cpu_ptr(np->stats, cpu);
1115                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
1116                 unsigned int start;
1117
1118                 do {
1119                         start = u64_stats_fetch_begin_irq(&stats->syncp);
1120
1121                         rx_packets = stats->rx_packets;
1122                         tx_packets = stats->tx_packets;
1123                         rx_bytes = stats->rx_bytes;
1124                         tx_bytes = stats->tx_bytes;
1125                 } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
1126
1127                 tot->rx_packets += rx_packets;
1128                 tot->tx_packets += tx_packets;
1129                 tot->rx_bytes   += rx_bytes;
1130                 tot->tx_bytes   += tx_bytes;
1131         }
1132
1133         tot->rx_errors  = dev->stats.rx_errors;
1134         tot->tx_dropped = dev->stats.tx_dropped;
1135
1136         return tot;
1137 }
1138
1139 static void xennet_release_tx_bufs(struct netfront_queue *queue)
1140 {
1141         struct sk_buff *skb;
1142         int i;
1143
1144         for (i = 0; i < NET_TX_RING_SIZE; i++) {
1145                 /* Skip over entries which are actually freelist references */
1146                 if (skb_entry_is_link(&queue->tx_skbs[i]))
1147                         continue;
1148
1149                 skb = queue->tx_skbs[i].skb;
1150                 get_page(queue->grant_tx_page[i]);
1151                 gnttab_end_foreign_access(queue->grant_tx_ref[i],
1152                                           GNTMAP_readonly,
1153                                           (unsigned long)page_address(queue->grant_tx_page[i]));
1154                 queue->grant_tx_page[i] = NULL;
1155                 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1156                 add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, i);
1157                 dev_kfree_skb_irq(skb);
1158         }
1159 }
1160
1161 static void xennet_release_rx_bufs(struct netfront_queue *queue)
1162 {
1163         int id, ref;
1164
1165         spin_lock_bh(&queue->rx_lock);
1166
1167         for (id = 0; id < NET_RX_RING_SIZE; id++) {
1168                 struct sk_buff *skb;
1169                 struct page *page;
1170
1171                 skb = queue->rx_skbs[id];
1172                 if (!skb)
1173                         continue;
1174
1175                 ref = queue->grant_rx_ref[id];
1176                 if (ref == GRANT_INVALID_REF)
1177                         continue;
1178
1179                 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
1180
1181                 /* gnttab_end_foreign_access() needs a page ref until
1182                  * foreign access is ended (which may be deferred).
1183                  */
1184                 get_page(page);
1185                 gnttab_end_foreign_access(ref, 0,
1186                                           (unsigned long)page_address(page));
1187                 queue->grant_rx_ref[id] = GRANT_INVALID_REF;
1188
1189                 kfree_skb(skb);
1190         }
1191
1192         spin_unlock_bh(&queue->rx_lock);
1193 }
1194
1195 static netdev_features_t xennet_fix_features(struct net_device *dev,
1196         netdev_features_t features)
1197 {
1198         struct netfront_info *np = netdev_priv(dev);
1199         int val;
1200
1201         if (features & NETIF_F_SG) {
1202                 if (xenbus_scanf(XBT_NIL, np->xbdev->otherend, "feature-sg",
1203                                  "%d", &val) < 0)
1204                         val = 0;
1205
1206                 if (!val)
1207                         features &= ~NETIF_F_SG;
1208         }
1209
1210         if (features & NETIF_F_IPV6_CSUM) {
1211                 if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
1212                                  "feature-ipv6-csum-offload", "%d", &val) < 0)
1213                         val = 0;
1214
1215                 if (!val)
1216                         features &= ~NETIF_F_IPV6_CSUM;
1217         }
1218
1219         if (features & NETIF_F_TSO) {
1220                 if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
1221                                  "feature-gso-tcpv4", "%d", &val) < 0)
1222                         val = 0;
1223
1224                 if (!val)
1225                         features &= ~NETIF_F_TSO;
1226         }
1227
1228         if (features & NETIF_F_TSO6) {
1229                 if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
1230                                  "feature-gso-tcpv6", "%d", &val) < 0)
1231                         val = 0;
1232
1233                 if (!val)
1234                         features &= ~NETIF_F_TSO6;
1235         }
1236
1237         return features;
1238 }
1239
1240 static int xennet_set_features(struct net_device *dev,
1241         netdev_features_t features)
1242 {
1243         if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) {
1244                 netdev_info(dev, "Reducing MTU because no SG offload");
1245                 dev->mtu = ETH_DATA_LEN;
1246         }
1247
1248         return 0;
1249 }
1250
1251 static irqreturn_t xennet_tx_interrupt(int irq, void *dev_id)
1252 {
1253         struct netfront_queue *queue = dev_id;
1254         unsigned long flags;
1255
1256         spin_lock_irqsave(&queue->tx_lock, flags);
1257         xennet_tx_buf_gc(queue);
1258         spin_unlock_irqrestore(&queue->tx_lock, flags);
1259
1260         return IRQ_HANDLED;
1261 }
1262
1263 static irqreturn_t xennet_rx_interrupt(int irq, void *dev_id)
1264 {
1265         struct netfront_queue *queue = dev_id;
1266         struct net_device *dev = queue->info->netdev;
1267
1268         if (likely(netif_carrier_ok(dev) &&
1269                    RING_HAS_UNCONSUMED_RESPONSES(&queue->rx)))
1270                 napi_schedule(&queue->napi);
1271
1272         return IRQ_HANDLED;
1273 }
1274
1275 static irqreturn_t xennet_interrupt(int irq, void *dev_id)
1276 {
1277         xennet_tx_interrupt(irq, dev_id);
1278         xennet_rx_interrupt(irq, dev_id);
1279         return IRQ_HANDLED;
1280 }
1281
1282 #ifdef CONFIG_NET_POLL_CONTROLLER
1283 static void xennet_poll_controller(struct net_device *dev)
1284 {
1285         /* Poll each queue */
1286         struct netfront_info *info = netdev_priv(dev);
1287         unsigned int num_queues = dev->real_num_tx_queues;
1288         unsigned int i;
1289         for (i = 0; i < num_queues; ++i)
1290                 xennet_interrupt(0, &info->queues[i]);
1291 }
1292 #endif
1293
1294 static const struct net_device_ops xennet_netdev_ops = {
1295         .ndo_open            = xennet_open,
1296         .ndo_stop            = xennet_close,
1297         .ndo_start_xmit      = xennet_start_xmit,
1298         .ndo_change_mtu      = xennet_change_mtu,
1299         .ndo_get_stats64     = xennet_get_stats64,
1300         .ndo_set_mac_address = eth_mac_addr,
1301         .ndo_validate_addr   = eth_validate_addr,
1302         .ndo_fix_features    = xennet_fix_features,
1303         .ndo_set_features    = xennet_set_features,
1304         .ndo_select_queue    = xennet_select_queue,
1305 #ifdef CONFIG_NET_POLL_CONTROLLER
1306         .ndo_poll_controller = xennet_poll_controller,
1307 #endif
1308 };
1309
1310 static struct net_device *xennet_create_dev(struct xenbus_device *dev)
1311 {
1312         int err;
1313         struct net_device *netdev;
1314         struct netfront_info *np;
1315
1316         netdev = alloc_etherdev_mq(sizeof(struct netfront_info), xennet_max_queues);
1317         if (!netdev)
1318                 return ERR_PTR(-ENOMEM);
1319
1320         np                   = netdev_priv(netdev);
1321         np->xbdev            = dev;
1322
1323         /* No need to use rtnl_lock() before the call below as it
1324          * happens before register_netdev().
1325          */
1326         netif_set_real_num_tx_queues(netdev, 0);
1327         np->queues = NULL;
1328
1329         err = -ENOMEM;
1330         np->stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1331         if (np->stats == NULL)
1332                 goto exit;
1333
1334         netdev->netdev_ops      = &xennet_netdev_ops;
1335
1336         netdev->features        = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
1337                                   NETIF_F_GSO_ROBUST;
1338         netdev->hw_features     = NETIF_F_SG |
1339                                   NETIF_F_IPV6_CSUM |
1340                                   NETIF_F_TSO | NETIF_F_TSO6;
1341
1342         /*
1343          * Assume that all hw features are available for now. This set
1344          * will be adjusted by the call to netdev_update_features() in
1345          * xennet_connect() which is the earliest point where we can
1346          * negotiate with the backend regarding supported features.
1347          */
1348         netdev->features |= netdev->hw_features;
1349
1350         netdev->ethtool_ops = &xennet_ethtool_ops;
1351         SET_NETDEV_DEV(netdev, &dev->dev);
1352
1353         netif_set_gso_max_size(netdev, XEN_NETIF_MAX_TX_SIZE - MAX_TCP_HEADER);
1354
1355         np->netdev = netdev;
1356
1357         netif_carrier_off(netdev);
1358
1359         return netdev;
1360
1361  exit:
1362         free_netdev(netdev);
1363         return ERR_PTR(err);
1364 }
1365
1366 /**
1367  * Entry point to this code when a new device is created.  Allocate the basic
1368  * structures and the ring buffers for communication with the backend, and
1369  * inform the backend of the appropriate details for those.
1370  */
1371 static int netfront_probe(struct xenbus_device *dev,
1372                           const struct xenbus_device_id *id)
1373 {
1374         int err;
1375         struct net_device *netdev;
1376         struct netfront_info *info;
1377
1378         netdev = xennet_create_dev(dev);
1379         if (IS_ERR(netdev)) {
1380                 err = PTR_ERR(netdev);
1381                 xenbus_dev_fatal(dev, err, "creating netdev");
1382                 return err;
1383         }
1384
1385         info = netdev_priv(netdev);
1386         dev_set_drvdata(&dev->dev, info);
1387
1388         err = register_netdev(info->netdev);
1389         if (err) {
1390                 pr_warn("%s: register_netdev err=%d\n", __func__, err);
1391                 goto fail;
1392         }
1393
1394         err = xennet_sysfs_addif(info->netdev);
1395         if (err) {
1396                 unregister_netdev(info->netdev);
1397                 pr_warn("%s: add sysfs failed err=%d\n", __func__, err);
1398                 goto fail;
1399         }
1400
1401         return 0;
1402
1403  fail:
1404         free_netdev(netdev);
1405         dev_set_drvdata(&dev->dev, NULL);
1406         return err;
1407 }
1408
1409 static void xennet_end_access(int ref, void *page)
1410 {
1411         /* This frees the page as a side-effect */
1412         if (ref != GRANT_INVALID_REF)
1413                 gnttab_end_foreign_access(ref, 0, (unsigned long)page);
1414 }
1415
1416 static void xennet_disconnect_backend(struct netfront_info *info)
1417 {
1418         unsigned int i = 0;
1419         unsigned int num_queues = info->netdev->real_num_tx_queues;
1420
1421         netif_carrier_off(info->netdev);
1422
1423         for (i = 0; i < num_queues; ++i) {
1424                 struct netfront_queue *queue = &info->queues[i];
1425
1426                 if (queue->tx_irq && (queue->tx_irq == queue->rx_irq))
1427                         unbind_from_irqhandler(queue->tx_irq, queue);
1428                 if (queue->tx_irq && (queue->tx_irq != queue->rx_irq)) {
1429                         unbind_from_irqhandler(queue->tx_irq, queue);
1430                         unbind_from_irqhandler(queue->rx_irq, queue);
1431                 }
1432                 queue->tx_evtchn = queue->rx_evtchn = 0;
1433                 queue->tx_irq = queue->rx_irq = 0;
1434
1435                 napi_synchronize(&queue->napi);
1436
1437                 xennet_release_tx_bufs(queue);
1438                 xennet_release_rx_bufs(queue);
1439                 gnttab_free_grant_references(queue->gref_tx_head);
1440                 gnttab_free_grant_references(queue->gref_rx_head);
1441
1442                 /* End access and free the pages */
1443                 xennet_end_access(queue->tx_ring_ref, queue->tx.sring);
1444                 xennet_end_access(queue->rx_ring_ref, queue->rx.sring);
1445
1446                 queue->tx_ring_ref = GRANT_INVALID_REF;
1447                 queue->rx_ring_ref = GRANT_INVALID_REF;
1448                 queue->tx.sring = NULL;
1449                 queue->rx.sring = NULL;
1450         }
1451 }
1452
1453 /**
1454  * We are reconnecting to the backend, due to a suspend/resume, or a backend
1455  * driver restart.  We tear down our netif structure and recreate it, but
1456  * leave the device-layer structures intact so that this is transparent to the
1457  * rest of the kernel.
1458  */
1459 static int netfront_resume(struct xenbus_device *dev)
1460 {
1461         struct netfront_info *info = dev_get_drvdata(&dev->dev);
1462
1463         dev_dbg(&dev->dev, "%s\n", dev->nodename);
1464
1465         xennet_disconnect_backend(info);
1466         return 0;
1467 }
1468
1469 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
1470 {
1471         char *s, *e, *macstr;
1472         int i;
1473
1474         macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
1475         if (IS_ERR(macstr))
1476                 return PTR_ERR(macstr);
1477
1478         for (i = 0; i < ETH_ALEN; i++) {
1479                 mac[i] = simple_strtoul(s, &e, 16);
1480                 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
1481                         kfree(macstr);
1482                         return -ENOENT;
1483                 }
1484                 s = e+1;
1485         }
1486
1487         kfree(macstr);
1488         return 0;
1489 }
1490
1491 static int setup_netfront_single(struct netfront_queue *queue)
1492 {
1493         int err;
1494
1495         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1496         if (err < 0)
1497                 goto fail;
1498
1499         err = bind_evtchn_to_irqhandler(queue->tx_evtchn,
1500                                         xennet_interrupt,
1501                                         0, queue->info->netdev->name, queue);
1502         if (err < 0)
1503                 goto bind_fail;
1504         queue->rx_evtchn = queue->tx_evtchn;
1505         queue->rx_irq = queue->tx_irq = err;
1506
1507         return 0;
1508
1509 bind_fail:
1510         xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1511         queue->tx_evtchn = 0;
1512 fail:
1513         return err;
1514 }
1515
1516 static int setup_netfront_split(struct netfront_queue *queue)
1517 {
1518         int err;
1519
1520         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1521         if (err < 0)
1522                 goto fail;
1523         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->rx_evtchn);
1524         if (err < 0)
1525                 goto alloc_rx_evtchn_fail;
1526
1527         snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
1528                  "%s-tx", queue->name);
1529         err = bind_evtchn_to_irqhandler(queue->tx_evtchn,
1530                                         xennet_tx_interrupt,
1531                                         0, queue->tx_irq_name, queue);
1532         if (err < 0)
1533                 goto bind_tx_fail;
1534         queue->tx_irq = err;
1535
1536         snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
1537                  "%s-rx", queue->name);
1538         err = bind_evtchn_to_irqhandler(queue->rx_evtchn,
1539                                         xennet_rx_interrupt,
1540                                         0, queue->rx_irq_name, queue);
1541         if (err < 0)
1542                 goto bind_rx_fail;
1543         queue->rx_irq = err;
1544
1545         return 0;
1546
1547 bind_rx_fail:
1548         unbind_from_irqhandler(queue->tx_irq, queue);
1549         queue->tx_irq = 0;
1550 bind_tx_fail:
1551         xenbus_free_evtchn(queue->info->xbdev, queue->rx_evtchn);
1552         queue->rx_evtchn = 0;
1553 alloc_rx_evtchn_fail:
1554         xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1555         queue->tx_evtchn = 0;
1556 fail:
1557         return err;
1558 }
1559
1560 static int setup_netfront(struct xenbus_device *dev,
1561                         struct netfront_queue *queue, unsigned int feature_split_evtchn)
1562 {
1563         struct xen_netif_tx_sring *txs;
1564         struct xen_netif_rx_sring *rxs;
1565         int err;
1566
1567         queue->tx_ring_ref = GRANT_INVALID_REF;
1568         queue->rx_ring_ref = GRANT_INVALID_REF;
1569         queue->rx.sring = NULL;
1570         queue->tx.sring = NULL;
1571
1572         txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1573         if (!txs) {
1574                 err = -ENOMEM;
1575                 xenbus_dev_fatal(dev, err, "allocating tx ring page");
1576                 goto fail;
1577         }
1578         SHARED_RING_INIT(txs);
1579         FRONT_RING_INIT(&queue->tx, txs, PAGE_SIZE);
1580
1581         err = xenbus_grant_ring(dev, virt_to_mfn(txs));
1582         if (err < 0)
1583                 goto grant_tx_ring_fail;
1584         queue->tx_ring_ref = err;
1585
1586         rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1587         if (!rxs) {
1588                 err = -ENOMEM;
1589                 xenbus_dev_fatal(dev, err, "allocating rx ring page");
1590                 goto alloc_rx_ring_fail;
1591         }
1592         SHARED_RING_INIT(rxs);
1593         FRONT_RING_INIT(&queue->rx, rxs, PAGE_SIZE);
1594
1595         err = xenbus_grant_ring(dev, virt_to_mfn(rxs));
1596         if (err < 0)
1597                 goto grant_rx_ring_fail;
1598         queue->rx_ring_ref = err;
1599
1600         if (feature_split_evtchn)
1601                 err = setup_netfront_split(queue);
1602         /* setup single event channel if
1603          *  a) feature-split-event-channels == 0
1604          *  b) feature-split-event-channels == 1 but failed to setup
1605          */
1606         if (!feature_split_evtchn || (feature_split_evtchn && err))
1607                 err = setup_netfront_single(queue);
1608
1609         if (err)
1610                 goto alloc_evtchn_fail;
1611
1612         return 0;
1613
1614         /* If we fail to setup netfront, it is safe to just revoke access to
1615          * granted pages because backend is not accessing it at this point.
1616          */
1617 alloc_evtchn_fail:
1618         gnttab_end_foreign_access_ref(queue->rx_ring_ref, 0);
1619 grant_rx_ring_fail:
1620         free_page((unsigned long)rxs);
1621 alloc_rx_ring_fail:
1622         gnttab_end_foreign_access_ref(queue->tx_ring_ref, 0);
1623 grant_tx_ring_fail:
1624         free_page((unsigned long)txs);
1625 fail:
1626         return err;
1627 }
1628
1629 /* Queue-specific initialisation
1630  * This used to be done in xennet_create_dev() but must now
1631  * be run per-queue.
1632  */
1633 static int xennet_init_queue(struct netfront_queue *queue)
1634 {
1635         unsigned short i;
1636         int err = 0;
1637
1638         spin_lock_init(&queue->tx_lock);
1639         spin_lock_init(&queue->rx_lock);
1640
1641         skb_queue_head_init(&queue->rx_batch);
1642         queue->rx_target     = RX_DFL_MIN_TARGET;
1643         queue->rx_min_target = RX_DFL_MIN_TARGET;
1644         queue->rx_max_target = RX_MAX_TARGET;
1645
1646         init_timer(&queue->rx_refill_timer);
1647         queue->rx_refill_timer.data = (unsigned long)queue;
1648         queue->rx_refill_timer.function = rx_refill_timeout;
1649
1650         snprintf(queue->name, sizeof(queue->name), "%s-q%u",
1651                  queue->info->netdev->name, queue->id);
1652
1653         /* Initialise tx_skbs as a free chain containing every entry. */
1654         queue->tx_skb_freelist = 0;
1655         for (i = 0; i < NET_TX_RING_SIZE; i++) {
1656                 skb_entry_set_link(&queue->tx_skbs[i], i+1);
1657                 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1658                 queue->grant_tx_page[i] = NULL;
1659         }
1660
1661         /* Clear out rx_skbs */
1662         for (i = 0; i < NET_RX_RING_SIZE; i++) {
1663                 queue->rx_skbs[i] = NULL;
1664                 queue->grant_rx_ref[i] = GRANT_INVALID_REF;
1665         }
1666
1667         /* A grant for every tx ring slot */
1668         if (gnttab_alloc_grant_references(TX_MAX_TARGET,
1669                                           &queue->gref_tx_head) < 0) {
1670                 pr_alert("can't alloc tx grant refs\n");
1671                 err = -ENOMEM;
1672                 goto exit;
1673         }
1674
1675         /* A grant for every rx ring slot */
1676         if (gnttab_alloc_grant_references(RX_MAX_TARGET,
1677                                           &queue->gref_rx_head) < 0) {
1678                 pr_alert("can't alloc rx grant refs\n");
1679                 err = -ENOMEM;
1680                 goto exit_free_tx;
1681         }
1682
1683         return 0;
1684
1685  exit_free_tx:
1686         gnttab_free_grant_references(queue->gref_tx_head);
1687  exit:
1688         return err;
1689 }
1690
1691 static int write_queue_xenstore_keys(struct netfront_queue *queue,
1692                            struct xenbus_transaction *xbt, int write_hierarchical)
1693 {
1694         /* Write the queue-specific keys into XenStore in the traditional
1695          * way for a single queue, or in a queue subkeys for multiple
1696          * queues.
1697          */
1698         struct xenbus_device *dev = queue->info->xbdev;
1699         int err;
1700         const char *message;
1701         char *path;
1702         size_t pathsize;
1703
1704         /* Choose the correct place to write the keys */
1705         if (write_hierarchical) {
1706                 pathsize = strlen(dev->nodename) + 10;
1707                 path = kzalloc(pathsize, GFP_KERNEL);
1708                 if (!path) {
1709                         err = -ENOMEM;
1710                         message = "out of memory while writing ring references";
1711                         goto error;
1712                 }
1713                 snprintf(path, pathsize, "%s/queue-%u",
1714                                 dev->nodename, queue->id);
1715         } else {
1716                 path = (char *)dev->nodename;
1717         }
1718
1719         /* Write ring references */
1720         err = xenbus_printf(*xbt, path, "tx-ring-ref", "%u",
1721                         queue->tx_ring_ref);
1722         if (err) {
1723                 message = "writing tx-ring-ref";
1724                 goto error;
1725         }
1726
1727         err = xenbus_printf(*xbt, path, "rx-ring-ref", "%u",
1728                         queue->rx_ring_ref);
1729         if (err) {
1730                 message = "writing rx-ring-ref";
1731                 goto error;
1732         }
1733
1734         /* Write event channels; taking into account both shared
1735          * and split event channel scenarios.
1736          */
1737         if (queue->tx_evtchn == queue->rx_evtchn) {
1738                 /* Shared event channel */
1739                 err = xenbus_printf(*xbt, path,
1740                                 "event-channel", "%u", queue->tx_evtchn);
1741                 if (err) {
1742                         message = "writing event-channel";
1743                         goto error;
1744                 }
1745         } else {
1746                 /* Split event channels */
1747                 err = xenbus_printf(*xbt, path,
1748                                 "event-channel-tx", "%u", queue->tx_evtchn);
1749                 if (err) {
1750                         message = "writing event-channel-tx";
1751                         goto error;
1752                 }
1753
1754                 err = xenbus_printf(*xbt, path,
1755                                 "event-channel-rx", "%u", queue->rx_evtchn);
1756                 if (err) {
1757                         message = "writing event-channel-rx";
1758                         goto error;
1759                 }
1760         }
1761
1762         if (write_hierarchical)
1763                 kfree(path);
1764         return 0;
1765
1766 error:
1767         if (write_hierarchical)
1768                 kfree(path);
1769         xenbus_dev_fatal(dev, err, "%s", message);
1770         return err;
1771 }
1772
1773 static void xennet_destroy_queues(struct netfront_info *info)
1774 {
1775         unsigned int i;
1776
1777         rtnl_lock();
1778
1779         for (i = 0; i < info->netdev->real_num_tx_queues; i++) {
1780                 struct netfront_queue *queue = &info->queues[i];
1781
1782                 if (netif_running(info->netdev))
1783                         napi_disable(&queue->napi);
1784                 netif_napi_del(&queue->napi);
1785         }
1786
1787         rtnl_unlock();
1788
1789         kfree(info->queues);
1790         info->queues = NULL;
1791 }
1792
1793 static int xennet_create_queues(struct netfront_info *info,
1794                                 unsigned int num_queues)
1795 {
1796         unsigned int i;
1797         int ret;
1798
1799         info->queues = kcalloc(num_queues, sizeof(struct netfront_queue),
1800                                GFP_KERNEL);
1801         if (!info->queues)
1802                 return -ENOMEM;
1803
1804         rtnl_lock();
1805
1806         for (i = 0; i < num_queues; i++) {
1807                 struct netfront_queue *queue = &info->queues[i];
1808
1809                 queue->id = i;
1810                 queue->info = info;
1811
1812                 ret = xennet_init_queue(queue);
1813                 if (ret < 0) {
1814                         dev_warn(&info->netdev->dev,
1815                                  "only created %d queues\n", i);
1816                         num_queues = i;
1817                         break;
1818                 }
1819
1820                 netif_napi_add(queue->info->netdev, &queue->napi,
1821                                xennet_poll, 64);
1822                 if (netif_running(info->netdev))
1823                         napi_enable(&queue->napi);
1824         }
1825
1826         netif_set_real_num_tx_queues(info->netdev, num_queues);
1827
1828         rtnl_unlock();
1829
1830         if (num_queues == 0) {
1831                 dev_err(&info->netdev->dev, "no queues\n");
1832                 return -EINVAL;
1833         }
1834         return 0;
1835 }
1836
1837 /* Common code used when first setting up, and when resuming. */
1838 static int talk_to_netback(struct xenbus_device *dev,
1839                            struct netfront_info *info)
1840 {
1841         const char *message;
1842         struct xenbus_transaction xbt;
1843         int err;
1844         unsigned int feature_split_evtchn;
1845         unsigned int i = 0;
1846         unsigned int max_queues = 0;
1847         struct netfront_queue *queue = NULL;
1848         unsigned int num_queues = 1;
1849
1850         info->netdev->irq = 0;
1851
1852         /* Check if backend supports multiple queues */
1853         err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
1854                            "multi-queue-max-queues", "%u", &max_queues);
1855         if (err < 0)
1856                 max_queues = 1;
1857         num_queues = min(max_queues, xennet_max_queues);
1858
1859         /* Check feature-split-event-channels */
1860         err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
1861                            "feature-split-event-channels", "%u",
1862                            &feature_split_evtchn);
1863         if (err < 0)
1864                 feature_split_evtchn = 0;
1865
1866         /* Read mac addr. */
1867         err = xen_net_read_mac(dev, info->netdev->dev_addr);
1868         if (err) {
1869                 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
1870                 goto out;
1871         }
1872
1873         if (info->queues)
1874                 xennet_destroy_queues(info);
1875
1876         err = xennet_create_queues(info, num_queues);
1877         if (err < 0)
1878                 goto destroy_ring;
1879
1880         /* Create shared ring, alloc event channel -- for each queue */
1881         for (i = 0; i < num_queues; ++i) {
1882                 queue = &info->queues[i];
1883                 err = setup_netfront(dev, queue, feature_split_evtchn);
1884                 if (err) {
1885                         /* setup_netfront() will tidy up the current
1886                          * queue on error, but we need to clean up
1887                          * those already allocated.
1888                          */
1889                         if (i > 0) {
1890                                 rtnl_lock();
1891                                 netif_set_real_num_tx_queues(info->netdev, i);
1892                                 rtnl_unlock();
1893                                 goto destroy_ring;
1894                         } else {
1895                                 goto out;
1896                         }
1897                 }
1898         }
1899
1900 again:
1901         err = xenbus_transaction_start(&xbt);
1902         if (err) {
1903                 xenbus_dev_fatal(dev, err, "starting transaction");
1904                 goto destroy_ring;
1905         }
1906
1907         if (num_queues == 1) {
1908                 err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
1909                 if (err)
1910                         goto abort_transaction_no_dev_fatal;
1911         } else {
1912                 /* Write the number of queues */
1913                 err = xenbus_printf(xbt, dev->nodename, "multi-queue-num-queues",
1914                                     "%u", num_queues);
1915                 if (err) {
1916                         message = "writing multi-queue-num-queues";
1917                         goto abort_transaction_no_dev_fatal;
1918                 }
1919
1920                 /* Write the keys for each queue */
1921                 for (i = 0; i < num_queues; ++i) {
1922                         queue = &info->queues[i];
1923                         err = write_queue_xenstore_keys(queue, &xbt, 1); /* hierarchical */
1924                         if (err)
1925                                 goto abort_transaction_no_dev_fatal;
1926                 }
1927         }
1928
1929         /* The remaining keys are not queue-specific */
1930         err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
1931                             1);
1932         if (err) {
1933                 message = "writing request-rx-copy";
1934                 goto abort_transaction;
1935         }
1936
1937         err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
1938         if (err) {
1939                 message = "writing feature-rx-notify";
1940                 goto abort_transaction;
1941         }
1942
1943         err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
1944         if (err) {
1945                 message = "writing feature-sg";
1946                 goto abort_transaction;
1947         }
1948
1949         err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
1950         if (err) {
1951                 message = "writing feature-gso-tcpv4";
1952                 goto abort_transaction;
1953         }
1954
1955         err = xenbus_write(xbt, dev->nodename, "feature-gso-tcpv6", "1");
1956         if (err) {
1957                 message = "writing feature-gso-tcpv6";
1958                 goto abort_transaction;
1959         }
1960
1961         err = xenbus_write(xbt, dev->nodename, "feature-ipv6-csum-offload",
1962                            "1");
1963         if (err) {
1964                 message = "writing feature-ipv6-csum-offload";
1965                 goto abort_transaction;
1966         }
1967
1968         err = xenbus_transaction_end(xbt, 0);
1969         if (err) {
1970                 if (err == -EAGAIN)
1971                         goto again;
1972                 xenbus_dev_fatal(dev, err, "completing transaction");
1973                 goto destroy_ring;
1974         }
1975
1976         return 0;
1977
1978  abort_transaction:
1979         xenbus_dev_fatal(dev, err, "%s", message);
1980 abort_transaction_no_dev_fatal:
1981         xenbus_transaction_end(xbt, 1);
1982  destroy_ring:
1983         xennet_disconnect_backend(info);
1984         kfree(info->queues);
1985         info->queues = NULL;
1986         rtnl_lock();
1987         netif_set_real_num_tx_queues(info->netdev, 0);
1988         rtnl_unlock();
1989  out:
1990         return err;
1991 }
1992
1993 static int xennet_connect(struct net_device *dev)
1994 {
1995         struct netfront_info *np = netdev_priv(dev);
1996         unsigned int num_queues = 0;
1997         int err;
1998         unsigned int feature_rx_copy;
1999         unsigned int j = 0;
2000         struct netfront_queue *queue = NULL;
2001
2002         err = xenbus_scanf(XBT_NIL, np->xbdev->otherend,
2003                            "feature-rx-copy", "%u", &feature_rx_copy);
2004         if (err != 1)
2005                 feature_rx_copy = 0;
2006
2007         if (!feature_rx_copy) {
2008                 dev_info(&dev->dev,
2009                          "backend does not support copying receive path\n");
2010                 return -ENODEV;
2011         }
2012
2013         err = talk_to_netback(np->xbdev, np);
2014         if (err)
2015                 return err;
2016
2017         /* talk_to_netback() sets the correct number of queues */
2018         num_queues = dev->real_num_tx_queues;
2019
2020         rtnl_lock();
2021         netdev_update_features(dev);
2022         rtnl_unlock();
2023
2024         /*
2025          * All public and private state should now be sane.  Get
2026          * ready to start sending and receiving packets and give the driver
2027          * domain a kick because we've probably just requeued some
2028          * packets.
2029          */
2030         netif_carrier_on(np->netdev);
2031         for (j = 0; j < num_queues; ++j) {
2032                 queue = &np->queues[j];
2033
2034                 notify_remote_via_irq(queue->tx_irq);
2035                 if (queue->tx_irq != queue->rx_irq)
2036                         notify_remote_via_irq(queue->rx_irq);
2037
2038                 spin_lock_irq(&queue->tx_lock);
2039                 xennet_tx_buf_gc(queue);
2040                 spin_unlock_irq(&queue->tx_lock);
2041
2042                 spin_lock_bh(&queue->rx_lock);
2043                 xennet_alloc_rx_buffers(queue);
2044                 spin_unlock_bh(&queue->rx_lock);
2045         }
2046
2047         return 0;
2048 }
2049
2050 /**
2051  * Callback received when the backend's state changes.
2052  */
2053 static void netback_changed(struct xenbus_device *dev,
2054                             enum xenbus_state backend_state)
2055 {
2056         struct netfront_info *np = dev_get_drvdata(&dev->dev);
2057         struct net_device *netdev = np->netdev;
2058
2059         dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
2060
2061         switch (backend_state) {
2062         case XenbusStateInitialising:
2063         case XenbusStateInitialised:
2064         case XenbusStateReconfiguring:
2065         case XenbusStateReconfigured:
2066         case XenbusStateUnknown:
2067                 break;
2068
2069         case XenbusStateInitWait:
2070                 if (dev->state != XenbusStateInitialising)
2071                         break;
2072                 if (xennet_connect(netdev) != 0)
2073                         break;
2074                 xenbus_switch_state(dev, XenbusStateConnected);
2075                 break;
2076
2077         case XenbusStateConnected:
2078                 netdev_notify_peers(netdev);
2079                 break;
2080
2081         case XenbusStateClosed:
2082                 if (dev->state == XenbusStateClosed)
2083                         break;
2084                 /* Missed the backend's CLOSING state -- fallthrough */
2085         case XenbusStateClosing:
2086                 xenbus_frontend_closed(dev);
2087                 break;
2088         }
2089 }
2090
2091 static const struct xennet_stat {
2092         char name[ETH_GSTRING_LEN];
2093         u16 offset;
2094 } xennet_stats[] = {
2095         {
2096                 "rx_gso_checksum_fixup",
2097                 offsetof(struct netfront_info, rx_gso_checksum_fixup)
2098         },
2099 };
2100
2101 static int xennet_get_sset_count(struct net_device *dev, int string_set)
2102 {
2103         switch (string_set) {
2104         case ETH_SS_STATS:
2105                 return ARRAY_SIZE(xennet_stats);
2106         default:
2107                 return -EINVAL;
2108         }
2109 }
2110
2111 static void xennet_get_ethtool_stats(struct net_device *dev,
2112                                      struct ethtool_stats *stats, u64 * data)
2113 {
2114         void *np = netdev_priv(dev);
2115         int i;
2116
2117         for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2118                 data[i] = atomic_read((atomic_t *)(np + xennet_stats[i].offset));
2119 }
2120
2121 static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data)
2122 {
2123         int i;
2124
2125         switch (stringset) {
2126         case ETH_SS_STATS:
2127                 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2128                         memcpy(data + i * ETH_GSTRING_LEN,
2129                                xennet_stats[i].name, ETH_GSTRING_LEN);
2130                 break;
2131         }
2132 }
2133
2134 static const struct ethtool_ops xennet_ethtool_ops =
2135 {
2136         .get_link = ethtool_op_get_link,
2137
2138         .get_sset_count = xennet_get_sset_count,
2139         .get_ethtool_stats = xennet_get_ethtool_stats,
2140         .get_strings = xennet_get_strings,
2141 };
2142
2143 #ifdef CONFIG_SYSFS
2144 static ssize_t show_rxbuf_min(struct device *dev,
2145                               struct device_attribute *attr, char *buf)
2146 {
2147         struct net_device *netdev = to_net_dev(dev);
2148         struct netfront_info *info = netdev_priv(netdev);
2149         unsigned int num_queues = netdev->real_num_tx_queues;
2150
2151         if (num_queues)
2152                 return sprintf(buf, "%u\n", info->queues[0].rx_min_target);
2153         else
2154                 return sprintf(buf, "%u\n", RX_MIN_TARGET);
2155 }
2156
2157 static ssize_t store_rxbuf_min(struct device *dev,
2158                                struct device_attribute *attr,
2159                                const char *buf, size_t len)
2160 {
2161         struct net_device *netdev = to_net_dev(dev);
2162         struct netfront_info *np = netdev_priv(netdev);
2163         unsigned int num_queues = netdev->real_num_tx_queues;
2164         char *endp;
2165         unsigned long target;
2166         unsigned int i;
2167         struct netfront_queue *queue;
2168
2169         if (!capable(CAP_NET_ADMIN))
2170                 return -EPERM;
2171
2172         target = simple_strtoul(buf, &endp, 0);
2173         if (endp == buf)
2174                 return -EBADMSG;
2175
2176         if (target < RX_MIN_TARGET)
2177                 target = RX_MIN_TARGET;
2178         if (target > RX_MAX_TARGET)
2179                 target = RX_MAX_TARGET;
2180
2181         for (i = 0; i < num_queues; ++i) {
2182                 queue = &np->queues[i];
2183                 spin_lock_bh(&queue->rx_lock);
2184                 if (target > queue->rx_max_target)
2185                         queue->rx_max_target = target;
2186                 queue->rx_min_target = target;
2187                 if (target > queue->rx_target)
2188                         queue->rx_target = target;
2189
2190                 xennet_alloc_rx_buffers(queue);
2191
2192                 spin_unlock_bh(&queue->rx_lock);
2193         }
2194         return len;
2195 }
2196
2197 static ssize_t show_rxbuf_max(struct device *dev,
2198                               struct device_attribute *attr, char *buf)
2199 {
2200         struct net_device *netdev = to_net_dev(dev);
2201         struct netfront_info *info = netdev_priv(netdev);
2202         unsigned int num_queues = netdev->real_num_tx_queues;
2203
2204         if (num_queues)
2205                 return sprintf(buf, "%u\n", info->queues[0].rx_max_target);
2206         else
2207                 return sprintf(buf, "%u\n", RX_MAX_TARGET);
2208 }
2209
2210 static ssize_t store_rxbuf_max(struct device *dev,
2211                                struct device_attribute *attr,
2212                                const char *buf, size_t len)
2213 {
2214         struct net_device *netdev = to_net_dev(dev);
2215         struct netfront_info *np = netdev_priv(netdev);
2216         unsigned int num_queues = netdev->real_num_tx_queues;
2217         char *endp;
2218         unsigned long target;
2219         unsigned int i = 0;
2220         struct netfront_queue *queue = NULL;
2221
2222         if (!capable(CAP_NET_ADMIN))
2223                 return -EPERM;
2224
2225         target = simple_strtoul(buf, &endp, 0);
2226         if (endp == buf)
2227                 return -EBADMSG;
2228
2229         if (target < RX_MIN_TARGET)
2230                 target = RX_MIN_TARGET;
2231         if (target > RX_MAX_TARGET)
2232                 target = RX_MAX_TARGET;
2233
2234         for (i = 0; i < num_queues; ++i) {
2235                 queue = &np->queues[i];
2236                 spin_lock_bh(&queue->rx_lock);
2237                 if (target < queue->rx_min_target)
2238                         queue->rx_min_target = target;
2239                 queue->rx_max_target = target;
2240                 if (target < queue->rx_target)
2241                         queue->rx_target = target;
2242
2243                 xennet_alloc_rx_buffers(queue);
2244
2245                 spin_unlock_bh(&queue->rx_lock);
2246         }
2247         return len;
2248 }
2249
2250 static ssize_t show_rxbuf_cur(struct device *dev,
2251                               struct device_attribute *attr, char *buf)
2252 {
2253         struct net_device *netdev = to_net_dev(dev);
2254         struct netfront_info *info = netdev_priv(netdev);
2255         unsigned int num_queues = netdev->real_num_tx_queues;
2256
2257         if (num_queues)
2258                 return sprintf(buf, "%u\n", info->queues[0].rx_target);
2259         else
2260                 return sprintf(buf, "0\n");
2261 }
2262
2263 static struct device_attribute xennet_attrs[] = {
2264         __ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf_min, store_rxbuf_min),
2265         __ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf_max, store_rxbuf_max),
2266         __ATTR(rxbuf_cur, S_IRUGO, show_rxbuf_cur, NULL),
2267 };
2268
2269 static int xennet_sysfs_addif(struct net_device *netdev)
2270 {
2271         int i;
2272         int err;
2273
2274         for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++) {
2275                 err = device_create_file(&netdev->dev,
2276                                            &xennet_attrs[i]);
2277                 if (err)
2278                         goto fail;
2279         }
2280         return 0;
2281
2282  fail:
2283         while (--i >= 0)
2284                 device_remove_file(&netdev->dev, &xennet_attrs[i]);
2285         return err;
2286 }
2287
2288 static void xennet_sysfs_delif(struct net_device *netdev)
2289 {
2290         int i;
2291
2292         for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++)
2293                 device_remove_file(&netdev->dev, &xennet_attrs[i]);
2294 }
2295
2296 #endif /* CONFIG_SYSFS */
2297
2298 static int xennet_remove(struct xenbus_device *dev)
2299 {
2300         struct netfront_info *info = dev_get_drvdata(&dev->dev);
2301         unsigned int num_queues = info->netdev->real_num_tx_queues;
2302         struct netfront_queue *queue = NULL;
2303         unsigned int i = 0;
2304
2305         dev_dbg(&dev->dev, "%s\n", dev->nodename);
2306
2307         xennet_disconnect_backend(info);
2308
2309         xennet_sysfs_delif(info->netdev);
2310
2311         unregister_netdev(info->netdev);
2312
2313         for (i = 0; i < num_queues; ++i) {
2314                 queue = &info->queues[i];
2315                 del_timer_sync(&queue->rx_refill_timer);
2316         }
2317
2318         if (num_queues) {
2319                 kfree(info->queues);
2320                 info->queues = NULL;
2321         }
2322
2323         free_percpu(info->stats);
2324
2325         free_netdev(info->netdev);
2326
2327         return 0;
2328 }
2329
2330 static const struct xenbus_device_id netfront_ids[] = {
2331         { "vif" },
2332         { "" }
2333 };
2334
2335 static struct xenbus_driver netfront_driver = {
2336         .ids = netfront_ids,
2337         .probe = netfront_probe,
2338         .remove = xennet_remove,
2339         .resume = netfront_resume,
2340         .otherend_changed = netback_changed,
2341 };
2342
2343 static int __init netif_init(void)
2344 {
2345         if (!xen_domain())
2346                 return -ENODEV;
2347
2348         if (!xen_has_pv_nic_devices())
2349                 return -ENODEV;
2350
2351         pr_info("Initialising Xen virtual ethernet driver\n");
2352
2353         /* Allow as many queues as there are CPUs, by default */
2354         xennet_max_queues = num_online_cpus();
2355
2356         return xenbus_register_frontend(&netfront_driver);
2357 }
2358 module_init(netif_init);
2359
2360
2361 static void __exit netif_exit(void)
2362 {
2363         xenbus_unregister_driver(&netfront_driver);
2364 }
2365 module_exit(netif_exit);
2366
2367 MODULE_DESCRIPTION("Xen virtual network device frontend");
2368 MODULE_LICENSE("GPL");
2369 MODULE_ALIAS("xen:vif");
2370 MODULE_ALIAS("xennet");