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 #include <linux/bpf.h>
  48 #include <net/page_pool/types.h>
  49 #include <linux/bpf_trace.h>
  50
  51 #include <xen/xen.h>
  52 #include <xen/xenbus.h>
  53 #include <xen/events.h>
  54 #include <xen/page.h>
  55 #include <xen/platform_pci.h>
  56 #include <xen/grant_table.h>
  57
  58 #include <xen/interface/io/netif.h>
  59 #include <xen/interface/memory.h>
  60 #include <xen/interface/grant_table.h>
  61
  62 /* Module parameters */
  63 #define MAX_QUEUES_DEFAULT 8
  64 static unsigned int xennet_max_queues;
  65 module_param_named(max_queues, xennet_max_queues, uint, 0644);
  66 MODULE_PARM_DESC(max_queues,
  67                  "Maximum number of queues per virtual interface");
  68
  69 static bool __read_mostly xennet_trusted = true;
  70 module_param_named(trusted, xennet_trusted, bool, 0644);
  71 MODULE_PARM_DESC(trusted, "Is the backend trusted");
  72
  73 #define XENNET_TIMEOUT  (5 * HZ)
  74
  75 static const struct ethtool_ops xennet_ethtool_ops;
  76
  77 struct netfront_cb {
  78         int pull_to;
  79 };
  80
  81 #define NETFRONT_SKB_CB(skb)    ((struct netfront_cb *)((skb)->cb))
  82
  83 #define RX_COPY_THRESHOLD 256
  84
  85 #define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, XEN_PAGE_SIZE)
  86 #define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, XEN_PAGE_SIZE)
  87
  88 /* Minimum number of Rx slots (includes slot for GSO metadata). */
  89 #define NET_RX_SLOTS_MIN (XEN_NETIF_NR_SLOTS_MIN + 1)
  90
  91 /* Queue name is interface name with "-qNNN" appended */
  92 #define QUEUE_NAME_SIZE (IFNAMSIZ + 6)
  93
  94 /* IRQ name is queue name with "-tx" or "-rx" appended */
  95 #define IRQ_NAME_SIZE (QUEUE_NAME_SIZE + 3)
  96
  97 static DECLARE_WAIT_QUEUE_HEAD(module_wq);
  98
  99 struct netfront_stats {
 100         u64                     packets;
 101         u64                     bytes;
 102         struct u64_stats_sync   syncp;
 103 };
 104
 105 struct netfront_info;
 106
 107 struct netfront_queue {
 108         unsigned int id; /* Queue ID, 0-based */
 109         char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
 110         struct netfront_info *info;
 111
 112         struct bpf_prog __rcu *xdp_prog;
 113
 114         struct napi_struct napi;
 115
 116         /* Split event channels support, tx_* == rx_* when using
 117          * single event channel.
 118          */
 119         unsigned int tx_evtchn, rx_evtchn;
 120         unsigned int tx_irq, rx_irq;
 121         /* Only used when split event channels support is enabled */
 122         char tx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-tx */
 123         char rx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-rx */
 124
 125         spinlock_t   tx_lock;
 126         struct xen_netif_tx_front_ring tx;
 127         int tx_ring_ref;
 128
 129         /*
 130          * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
 131          * are linked from tx_skb_freelist through tx_link.
 132          */
 133         struct sk_buff *tx_skbs[NET_TX_RING_SIZE];
 134         unsigned short tx_link[NET_TX_RING_SIZE];
 135 #define TX_LINK_NONE 0xffff
 136 #define TX_PENDING   0xfffe
 137         grant_ref_t gref_tx_head;
 138         grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
 139         struct page *grant_tx_page[NET_TX_RING_SIZE];
 140         unsigned tx_skb_freelist;
 141         unsigned int tx_pend_queue;
 142
 143         spinlock_t   rx_lock ____cacheline_aligned_in_smp;
 144         struct xen_netif_rx_front_ring rx;
 145         int rx_ring_ref;
 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 int rx_rsp_unconsumed;
 154         spinlock_t rx_cons_lock;
 155
 156         struct page_pool *page_pool;
 157         struct xdp_rxq_info xdp_rxq;
 158 };
 159
 160 struct netfront_info {
 161         struct list_head list;
 162         struct net_device *netdev;
 163
 164         struct xenbus_device *xbdev;
 165
 166         /* Multi-queue support */
 167         struct netfront_queue *queues;
 168
 169         /* Statistics */
 170         struct netfront_stats __percpu *rx_stats;
 171         struct netfront_stats __percpu *tx_stats;
 172
 173         /* XDP state */
 174         bool netback_has_xdp_headroom;
 175         bool netfront_xdp_enabled;
 176
 177         /* Is device behaving sane? */
 178         bool broken;
 179
 180         /* Should skbs be bounced into a zeroed buffer? */
 181         bool bounce;
 182
 183         atomic_t rx_gso_checksum_fixup;
 184 };
 185
 186 struct netfront_rx_info {
 187         struct xen_netif_rx_response rx;
 188         struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
 189 };
 190
 191 /*
 192  * Access macros for acquiring freeing slots in tx_skbs[].
 193  */
 194
 195 static void add_id_to_list(unsigned *head, unsigned short *list,
 196                            unsigned short id)
 197 {
 198         list[id] = *head;
 199         *head = id;
 200 }
 201
 202 static unsigned short get_id_from_list(unsigned *head, unsigned short *list)
 203 {
 204         unsigned int id = *head;
 205
 206         if (id != TX_LINK_NONE) {
 207                 *head = list[id];
 208                 list[id] = TX_LINK_NONE;
 209         }
 210         return id;
 211 }
 212
 213 static int xennet_rxidx(RING_IDX idx)
 214 {
 215         return idx & (NET_RX_RING_SIZE - 1);
 216 }
 217
 218 static struct sk_buff *xennet_get_rx_skb(struct netfront_queue *queue,
 219                                          RING_IDX ri)
 220 {
 221         int i = xennet_rxidx(ri);
 222         struct sk_buff *skb = queue->rx_skbs[i];
 223         queue->rx_skbs[i] = NULL;
 224         return skb;
 225 }
 226
 227 static grant_ref_t xennet_get_rx_ref(struct netfront_queue *queue,
 228                                             RING_IDX ri)
 229 {
 230         int i = xennet_rxidx(ri);
 231         grant_ref_t ref = queue->grant_rx_ref[i];
 232         queue->grant_rx_ref[i] = INVALID_GRANT_REF;
 233         return ref;
 234 }
 235
 236 #ifdef CONFIG_SYSFS
 237 static const struct attribute_group xennet_dev_group;
 238 #endif
 239
 240 static bool xennet_can_sg(struct net_device *dev)
 241 {
 242         return dev->features & NETIF_F_SG;
 243 }
 244
 245
 246 static void rx_refill_timeout(struct timer_list *t)
 247 {
 248         struct netfront_queue *queue = from_timer(queue, t, rx_refill_timer);
 249         napi_schedule(&queue->napi);
 250 }
 251
 252 static int netfront_tx_slot_available(struct netfront_queue *queue)
 253 {
 254         return (queue->tx.req_prod_pvt - queue->tx.rsp_cons) <
 255                 (NET_TX_RING_SIZE - XEN_NETIF_NR_SLOTS_MIN - 1);
 256 }
 257
 258 static void xennet_maybe_wake_tx(struct netfront_queue *queue)
 259 {
 260         struct net_device *dev = queue->info->netdev;
 261         struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, queue->id);
 262
 263         if (unlikely(netif_tx_queue_stopped(dev_queue)) &&
 264             netfront_tx_slot_available(queue) &&
 265             likely(netif_running(dev)))
 266                 netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id));
 267 }
 268
 269
 270 static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue)
 271 {
 272         struct sk_buff *skb;
 273         struct page *page;
 274
 275         skb = __netdev_alloc_skb(queue->info->netdev,
 276                                  RX_COPY_THRESHOLD + NET_IP_ALIGN,
 277                                  GFP_ATOMIC | __GFP_NOWARN);
 278         if (unlikely(!skb))
 279                 return NULL;
 280
 281         page = page_pool_alloc_pages(queue->page_pool,
 282                                      GFP_ATOMIC | __GFP_NOWARN | __GFP_ZERO);
 283         if (unlikely(!page)) {
 284                 kfree_skb(skb);
 285                 return NULL;
 286         }
 287         skb_add_rx_frag(skb, 0, page, 0, 0, PAGE_SIZE);
 288         skb_mark_for_recycle(skb);
 289
 290         /* Align ip header to a 16 bytes boundary */
 291         skb_reserve(skb, NET_IP_ALIGN);
 292         skb->dev = queue->info->netdev;
 293
 294         return skb;
 295 }
 296
 297
 298 static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
 299 {
 300         RING_IDX req_prod = queue->rx.req_prod_pvt;
 301         int notify;
 302         int err = 0;
 303
 304         if (unlikely(!netif_carrier_ok(queue->info->netdev)))
 305                 return;
 306
 307         for (req_prod = queue->rx.req_prod_pvt;
 308              req_prod - queue->rx.rsp_cons < NET_RX_RING_SIZE;
 309              req_prod++) {
 310                 struct sk_buff *skb;
 311                 unsigned short id;
 312                 grant_ref_t ref;
 313                 struct page *page;
 314                 struct xen_netif_rx_request *req;
 315
 316                 skb = xennet_alloc_one_rx_buffer(queue);
 317                 if (!skb) {
 318                         err = -ENOMEM;
 319                         break;
 320                 }
 321
 322                 id = xennet_rxidx(req_prod);
 323
 324                 BUG_ON(queue->rx_skbs[id]);
 325                 queue->rx_skbs[id] = skb;
 326
 327                 ref = gnttab_claim_grant_reference(&queue->gref_rx_head);
 328                 WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
 329                 queue->grant_rx_ref[id] = ref;
 330
 331                 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
 332
 333                 req = RING_GET_REQUEST(&queue->rx, req_prod);
 334                 gnttab_page_grant_foreign_access_ref_one(ref,
 335                                                          queue->info->xbdev->otherend_id,
 336                                                          page,
 337                                                          0);
 338                 req->id = id;
 339                 req->gref = ref;
 340         }
 341
 342         queue->rx.req_prod_pvt = req_prod;
 343
 344         /* Try again later if there are not enough requests or skb allocation
 345          * failed.
 346          * Enough requests is quantified as the sum of newly created slots and
 347          * the unconsumed slots at the backend.
 348          */
 349         if (req_prod - queue->rx.rsp_cons < NET_RX_SLOTS_MIN ||
 350             unlikely(err)) {
 351                 mod_timer(&queue->rx_refill_timer, jiffies + (HZ/10));
 352                 return;
 353         }
 354
 355         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->rx, notify);
 356         if (notify)
 357                 notify_remote_via_irq(queue->rx_irq);
 358 }
 359
 360 static int xennet_open(struct net_device *dev)
 361 {
 362         struct netfront_info *np = netdev_priv(dev);
 363         unsigned int num_queues = dev->real_num_tx_queues;
 364         unsigned int i = 0;
 365         struct netfront_queue *queue = NULL;
 366
 367         if (!np->queues || np->broken)
 368                 return -ENODEV;
 369
 370         for (i = 0; i < num_queues; ++i) {
 371                 queue = &np->queues[i];
 372                 napi_enable(&queue->napi);
 373
 374                 spin_lock_bh(&queue->rx_lock);
 375                 if (netif_carrier_ok(dev)) {
 376                         xennet_alloc_rx_buffers(queue);
 377                         queue->rx.sring->rsp_event = queue->rx.rsp_cons + 1;
 378                         if (RING_HAS_UNCONSUMED_RESPONSES(&queue->rx))
 379                                 napi_schedule(&queue->napi);
 380                 }
 381                 spin_unlock_bh(&queue->rx_lock);
 382         }
 383
 384         netif_tx_start_all_queues(dev);
 385
 386         return 0;
 387 }
 388
 389 static bool xennet_tx_buf_gc(struct netfront_queue *queue)
 390 {
 391         RING_IDX cons, prod;
 392         unsigned short id;
 393         struct sk_buff *skb;
 394         bool more_to_do;
 395         bool work_done = false;
 396         const struct device *dev = &queue->info->netdev->dev;
 397
 398         BUG_ON(!netif_carrier_ok(queue->info->netdev));
 399
 400         do {
 401                 prod = queue->tx.sring->rsp_prod;
 402                 if (RING_RESPONSE_PROD_OVERFLOW(&queue->tx, prod)) {
 403                         dev_alert(dev, "Illegal number of responses %u\n",
 404                                   prod - queue->tx.rsp_cons);
 405                         goto err;
 406                 }
 407                 rmb(); /* Ensure we see responses up to 'rp'. */
 408
 409                 for (cons = queue->tx.rsp_cons; cons != prod; cons++) {
 410                         struct xen_netif_tx_response txrsp;
 411
 412                         work_done = true;
 413
 414                         RING_COPY_RESPONSE(&queue->tx, cons, &txrsp);
 415                         if (txrsp.status == XEN_NETIF_RSP_NULL)
 416                                 continue;
 417
 418                         id = txrsp.id;
 419                         if (id >= RING_SIZE(&queue->tx)) {
 420                                 dev_alert(dev,
 421                                           "Response has incorrect id (%u)\n",
 422                                           id);
 423                                 goto err;
 424                         }
 425                         if (queue->tx_link[id] != TX_PENDING) {
 426                                 dev_alert(dev,
 427                                           "Response for inactive request\n");
 428                                 goto err;
 429                         }
 430
 431                         queue->tx_link[id] = TX_LINK_NONE;
 432                         skb = queue->tx_skbs[id];
 433                         queue->tx_skbs[id] = NULL;
 434                         if (unlikely(!gnttab_end_foreign_access_ref(
 435                                 queue->grant_tx_ref[id]))) {
 436                                 dev_alert(dev,
 437                                           "Grant still in use by backend domain\n");
 438                                 goto err;
 439                         }
 440                         gnttab_release_grant_reference(
 441                                 &queue->gref_tx_head, queue->grant_tx_ref[id]);
 442                         queue->grant_tx_ref[id] = INVALID_GRANT_REF;
 443                         queue->grant_tx_page[id] = NULL;
 444                         add_id_to_list(&queue->tx_skb_freelist, queue->tx_link, id);
 445                         dev_kfree_skb_irq(skb);
 446                 }
 447
 448                 queue->tx.rsp_cons = prod;
 449
 450                 RING_FINAL_CHECK_FOR_RESPONSES(&queue->tx, more_to_do);
 451         } while (more_to_do);
 452
 453         xennet_maybe_wake_tx(queue);
 454
 455         return work_done;
 456
 457  err:
 458         queue->info->broken = true;
 459         dev_alert(dev, "Disabled for further use\n");
 460
 461         return work_done;
 462 }
 463
 464 struct xennet_gnttab_make_txreq {
 465         struct netfront_queue *queue;
 466         struct sk_buff *skb;
 467         struct page *page;
 468         struct xen_netif_tx_request *tx;      /* Last request on ring page */
 469         struct xen_netif_tx_request tx_local; /* Last request local copy*/
 470         unsigned int size;
 471 };
 472
 473 static void xennet_tx_setup_grant(unsigned long gfn, unsigned int offset,
 474                                   unsigned int len, void *data)
 475 {
 476         struct xennet_gnttab_make_txreq *info = data;
 477         unsigned int id;
 478         struct xen_netif_tx_request *tx;
 479         grant_ref_t ref;
 480         /* convenient aliases */
 481         struct page *page = info->page;
 482         struct netfront_queue *queue = info->queue;
 483         struct sk_buff *skb = info->skb;
 484
 485         id = get_id_from_list(&queue->tx_skb_freelist, queue->tx_link);
 486         tx = RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
 487         ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
 488         WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
 489
 490         gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,
 491                                         gfn, GNTMAP_readonly);
 492
 493         queue->tx_skbs[id] = skb;
 494         queue->grant_tx_page[id] = page;
 495         queue->grant_tx_ref[id] = ref;
 496
 497         info->tx_local.id = id;
 498         info->tx_local.gref = ref;
 499         info->tx_local.offset = offset;
 500         info->tx_local.size = len;
 501         info->tx_local.flags = 0;
 502
 503         *tx = info->tx_local;
 504
 505         /*
 506          * Put the request in the pending queue, it will be set to be pending
 507          * when the producer index is about to be raised.
 508          */
 509         add_id_to_list(&queue->tx_pend_queue, queue->tx_link, id);
 510
 511         info->tx = tx;
 512         info->size += info->tx_local.size;
 513 }
 514
 515 static struct xen_netif_tx_request *xennet_make_first_txreq(
 516         struct xennet_gnttab_make_txreq *info,
 517         unsigned int offset, unsigned int len)
 518 {
 519         info->size = 0;
 520
 521         gnttab_for_one_grant(info->page, offset, len, xennet_tx_setup_grant, info);
 522
 523         return info->tx;
 524 }
 525
 526 static void xennet_make_one_txreq(unsigned long gfn, unsigned int offset,
 527                                   unsigned int len, void *data)
 528 {
 529         struct xennet_gnttab_make_txreq *info = data;
 530
 531         info->tx->flags |= XEN_NETTXF_more_data;
 532         skb_get(info->skb);
 533         xennet_tx_setup_grant(gfn, offset, len, data);
 534 }
 535
 536 static void xennet_make_txreqs(
 537         struct xennet_gnttab_make_txreq *info,
 538         struct page *page,
 539         unsigned int offset, unsigned int len)
 540 {
 541         /* Skip unused frames from start of page */
 542         page += offset >> PAGE_SHIFT;
 543         offset &= ~PAGE_MASK;
 544
 545         while (len) {
 546                 info->page = page;
 547                 info->size = 0;
 548
 549                 gnttab_foreach_grant_in_range(page, offset, len,
 550                                               xennet_make_one_txreq,
 551                                               info);
 552
 553                 page++;
 554                 offset = 0;
 555                 len -= info->size;
 556         }
 557 }
 558
 559 /*
 560  * Count how many ring slots are required to send this skb. Each frag
 561  * might be a compound page.
 562  */
 563 static int xennet_count_skb_slots(struct sk_buff *skb)
 564 {
 565         int i, frags = skb_shinfo(skb)->nr_frags;
 566         int slots;
 567
 568         slots = gnttab_count_grant(offset_in_page(skb->data),
 569                                    skb_headlen(skb));
 570
 571         for (i = 0; i < frags; i++) {
 572                 skb_frag_t *frag = skb_shinfo(skb)->frags + i;
 573                 unsigned long size = skb_frag_size(frag);
 574                 unsigned long offset = skb_frag_off(frag);
 575
 576                 /* Skip unused frames from start of page */
 577                 offset &= ~PAGE_MASK;
 578
 579                 slots += gnttab_count_grant(offset, size);
 580         }
 581
 582         return slots;
 583 }
 584
 585 static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb,
 586                                struct net_device *sb_dev)
 587 {
 588         unsigned int num_queues = dev->real_num_tx_queues;
 589         u32 hash;
 590         u16 queue_idx;
 591
 592         /* First, check if there is only one queue */
 593         if (num_queues == 1) {
 594                 queue_idx = 0;
 595         } else {
 596                 hash = skb_get_hash(skb);
 597                 queue_idx = hash % num_queues;
 598         }
 599
 600         return queue_idx;
 601 }
 602
 603 static void xennet_mark_tx_pending(struct netfront_queue *queue)
 604 {
 605         unsigned int i;
 606
 607         while ((i = get_id_from_list(&queue->tx_pend_queue, queue->tx_link)) !=
 608                TX_LINK_NONE)
 609                 queue->tx_link[i] = TX_PENDING;
 610 }
 611
 612 static int xennet_xdp_xmit_one(struct net_device *dev,
 613                                struct netfront_queue *queue,
 614                                struct xdp_frame *xdpf)
 615 {
 616         struct netfront_info *np = netdev_priv(dev);
 617         struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
 618         struct xennet_gnttab_make_txreq info = {
 619                 .queue = queue,
 620                 .skb = NULL,
 621                 .page = virt_to_page(xdpf->data),
 622         };
 623         int notify;
 624
 625         xennet_make_first_txreq(&info,
 626                                 offset_in_page(xdpf->data),
 627                                 xdpf->len);
 628
 629         xennet_mark_tx_pending(queue);
 630
 631         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
 632         if (notify)
 633                 notify_remote_via_irq(queue->tx_irq);
 634
 635         u64_stats_update_begin(&tx_stats->syncp);
 636         tx_stats->bytes += xdpf->len;
 637         tx_stats->packets++;
 638         u64_stats_update_end(&tx_stats->syncp);
 639
 640         xennet_tx_buf_gc(queue);
 641
 642         return 0;
 643 }
 644
 645 static int xennet_xdp_xmit(struct net_device *dev, int n,
 646                            struct xdp_frame **frames, u32 flags)
 647 {
 648         unsigned int num_queues = dev->real_num_tx_queues;
 649         struct netfront_info *np = netdev_priv(dev);
 650         struct netfront_queue *queue = NULL;
 651         unsigned long irq_flags;
 652         int nxmit = 0;
 653         int i;
 654
 655         if (unlikely(np->broken))
 656                 return -ENODEV;
 657         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
 658                 return -EINVAL;
 659
 660         queue = &np->queues[smp_processor_id() % num_queues];
 661
 662         spin_lock_irqsave(&queue->tx_lock, irq_flags);
 663         for (i = 0; i < n; i++) {
 664                 struct xdp_frame *xdpf = frames[i];
 665
 666                 if (!xdpf)
 667                         continue;
 668                 if (xennet_xdp_xmit_one(dev, queue, xdpf))
 669                         break;
 670                 nxmit++;
 671         }
 672         spin_unlock_irqrestore(&queue->tx_lock, irq_flags);
 673
 674         return nxmit;
 675 }
 676
 677 static struct sk_buff *bounce_skb(const struct sk_buff *skb)
 678 {
 679         unsigned int headerlen = skb_headroom(skb);
 680         /* Align size to allocate full pages and avoid contiguous data leaks */
 681         unsigned int size = ALIGN(skb_end_offset(skb) + skb->data_len,
 682                                   XEN_PAGE_SIZE);
 683         struct sk_buff *n = alloc_skb(size, GFP_ATOMIC | __GFP_ZERO);
 684
 685         if (!n)
 686                 return NULL;
 687
 688         if (!IS_ALIGNED((uintptr_t)n->head, XEN_PAGE_SIZE)) {
 689                 WARN_ONCE(1, "misaligned skb allocated\n");
 690                 kfree_skb(n);
 691                 return NULL;
 692         }
 693
 694         /* Set the data pointer */
 695         skb_reserve(n, headerlen);
 696         /* Set the tail pointer and length */
 697         skb_put(n, skb->len);
 698
 699         BUG_ON(skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len));
 700
 701         skb_copy_header(n, skb);
 702         return n;
 703 }
 704
 705 #define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1)
 706
 707 static netdev_tx_t xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 708 {
 709         struct netfront_info *np = netdev_priv(dev);
 710         struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
 711         struct xen_netif_tx_request *first_tx;
 712         unsigned int i;
 713         int notify;
 714         int slots;
 715         struct page *page;
 716         unsigned int offset;
 717         unsigned int len;
 718         unsigned long flags;
 719         struct netfront_queue *queue = NULL;
 720         struct xennet_gnttab_make_txreq info = { };
 721         unsigned int num_queues = dev->real_num_tx_queues;
 722         u16 queue_index;
 723         struct sk_buff *nskb;
 724
 725         /* Drop the packet if no queues are set up */
 726         if (num_queues < 1)
 727                 goto drop;
 728         if (unlikely(np->broken))
 729                 goto drop;
 730         /* Determine which queue to transmit this SKB on */
 731         queue_index = skb_get_queue_mapping(skb);
 732         queue = &np->queues[queue_index];
 733
 734         /* If skb->len is too big for wire format, drop skb and alert
 735          * user about misconfiguration.
 736          */
 737         if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) {
 738                 net_alert_ratelimited(
 739                         "xennet: skb->len = %u, too big for wire format\n",
 740                         skb->len);
 741                 goto drop;
 742         }
 743
 744         slots = xennet_count_skb_slots(skb);
 745         if (unlikely(slots > MAX_XEN_SKB_FRAGS + 1)) {
 746                 net_dbg_ratelimited("xennet: skb rides the rocket: %d slots, %d bytes\n",
 747                                     slots, skb->len);
 748                 if (skb_linearize(skb))
 749                         goto drop;
 750         }
 751
 752         page = virt_to_page(skb->data);
 753         offset = offset_in_page(skb->data);
 754
 755         /* The first req should be at least ETH_HLEN size or the packet will be
 756          * dropped by netback.
 757          *
 758          * If the backend is not trusted bounce all data to zeroed pages to
 759          * avoid exposing contiguous data on the granted page not belonging to
 760          * the skb.
 761          */
 762         if (np->bounce || unlikely(PAGE_SIZE - offset < ETH_HLEN)) {
 763                 nskb = bounce_skb(skb);
 764                 if (!nskb)
 765                         goto drop;
 766                 dev_consume_skb_any(skb);
 767                 skb = nskb;
 768                 page = virt_to_page(skb->data);
 769                 offset = offset_in_page(skb->data);
 770         }
 771
 772         len = skb_headlen(skb);
 773
 774         spin_lock_irqsave(&queue->tx_lock, flags);
 775
 776         if (unlikely(!netif_carrier_ok(dev) ||
 777                      (slots > 1 && !xennet_can_sg(dev)) ||
 778                      netif_needs_gso(skb, netif_skb_features(skb)))) {
 779                 spin_unlock_irqrestore(&queue->tx_lock, flags);
 780                 goto drop;
 781         }
 782
 783         /* First request for the linear area. */
 784         info.queue = queue;
 785         info.skb = skb;
 786         info.page = page;
 787         first_tx = xennet_make_first_txreq(&info, offset, len);
 788         offset += info.tx_local.size;
 789         if (offset == PAGE_SIZE) {
 790                 page++;
 791                 offset = 0;
 792         }
 793         len -= info.tx_local.size;
 794
 795         if (skb->ip_summed == CHECKSUM_PARTIAL)
 796                 /* local packet? */
 797                 first_tx->flags |= XEN_NETTXF_csum_blank |
 798                                    XEN_NETTXF_data_validated;
 799         else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
 800                 /* remote but checksummed. */
 801                 first_tx->flags |= XEN_NETTXF_data_validated;
 802
 803         /* Optional extra info after the first request. */
 804         if (skb_shinfo(skb)->gso_size) {
 805                 struct xen_netif_extra_info *gso;
 806
 807                 gso = (struct xen_netif_extra_info *)
 808                         RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
 809
 810                 first_tx->flags |= XEN_NETTXF_extra_info;
 811
 812                 gso->u.gso.size = skb_shinfo(skb)->gso_size;
 813                 gso->u.gso.type = (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) ?
 814                         XEN_NETIF_GSO_TYPE_TCPV6 :
 815                         XEN_NETIF_GSO_TYPE_TCPV4;
 816                 gso->u.gso.pad = 0;
 817                 gso->u.gso.features = 0;
 818
 819                 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
 820                 gso->flags = 0;
 821         }
 822
 823         /* Requests for the rest of the linear area. */
 824         xennet_make_txreqs(&info, page, offset, len);
 825
 826         /* Requests for all the frags. */
 827         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 828                 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 829                 xennet_make_txreqs(&info, skb_frag_page(frag),
 830                                         skb_frag_off(frag),
 831                                         skb_frag_size(frag));
 832         }
 833
 834         /* First request has the packet length. */
 835         first_tx->size = skb->len;
 836
 837         /* timestamp packet in software */
 838         skb_tx_timestamp(skb);
 839
 840         xennet_mark_tx_pending(queue);
 841
 842         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
 843         if (notify)
 844                 notify_remote_via_irq(queue->tx_irq);
 845
 846         u64_stats_update_begin(&tx_stats->syncp);
 847         tx_stats->bytes += skb->len;
 848         tx_stats->packets++;
 849         u64_stats_update_end(&tx_stats->syncp);
 850
 851         /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
 852         xennet_tx_buf_gc(queue);
 853
 854         if (!netfront_tx_slot_available(queue))
 855                 netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
 856
 857         spin_unlock_irqrestore(&queue->tx_lock, flags);
 858
 859         return NETDEV_TX_OK;
 860
 861  drop:
 862         dev->stats.tx_dropped++;
 863         dev_kfree_skb_any(skb);
 864         return NETDEV_TX_OK;
 865 }
 866
 867 static int xennet_close(struct net_device *dev)
 868 {
 869         struct netfront_info *np = netdev_priv(dev);
 870         unsigned int num_queues = dev->real_num_tx_queues;
 871         unsigned int i;
 872         struct netfront_queue *queue;
 873         netif_tx_stop_all_queues(np->netdev);
 874         for (i = 0; i < num_queues; ++i) {
 875                 queue = &np->queues[i];
 876                 napi_disable(&queue->napi);
 877         }
 878         return 0;
 879 }
 880
 881 static void xennet_destroy_queues(struct netfront_info *info)
 882 {
 883         unsigned int i;
 884
 885         for (i = 0; i < info->netdev->real_num_tx_queues; i++) {
 886                 struct netfront_queue *queue = &info->queues[i];
 887
 888                 if (netif_running(info->netdev))
 889                         napi_disable(&queue->napi);
 890                 netif_napi_del(&queue->napi);
 891         }
 892
 893         kfree(info->queues);
 894         info->queues = NULL;
 895 }
 896
 897 static void xennet_uninit(struct net_device *dev)
 898 {
 899         struct netfront_info *np = netdev_priv(dev);
 900         xennet_destroy_queues(np);
 901 }
 902
 903 static void xennet_set_rx_rsp_cons(struct netfront_queue *queue, RING_IDX val)
 904 {
 905         unsigned long flags;
 906
 907         spin_lock_irqsave(&queue->rx_cons_lock, flags);
 908         queue->rx.rsp_cons = val;
 909         queue->rx_rsp_unconsumed = XEN_RING_NR_UNCONSUMED_RESPONSES(&queue->rx);
 910         spin_unlock_irqrestore(&queue->rx_cons_lock, flags);
 911 }
 912
 913 static void xennet_move_rx_slot(struct netfront_queue *queue, struct sk_buff *skb,
 914                                 grant_ref_t ref)
 915 {
 916         int new = xennet_rxidx(queue->rx.req_prod_pvt);
 917
 918         BUG_ON(queue->rx_skbs[new]);
 919         queue->rx_skbs[new] = skb;
 920         queue->grant_rx_ref[new] = ref;
 921         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->id = new;
 922         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->gref = ref;
 923         queue->rx.req_prod_pvt++;
 924 }
 925
 926 static int xennet_get_extras(struct netfront_queue *queue,
 927                              struct xen_netif_extra_info *extras,
 928                              RING_IDX rp)
 929
 930 {
 931         struct xen_netif_extra_info extra;
 932         struct device *dev = &queue->info->netdev->dev;
 933         RING_IDX cons = queue->rx.rsp_cons;
 934         int err = 0;
 935
 936         do {
 937                 struct sk_buff *skb;
 938                 grant_ref_t ref;
 939
 940                 if (unlikely(cons + 1 == rp)) {
 941                         if (net_ratelimit())
 942                                 dev_warn(dev, "Missing extra info\n");
 943                         err = -EBADR;
 944                         break;
 945                 }
 946
 947                 RING_COPY_RESPONSE(&queue->rx, ++cons, &extra);
 948
 949                 if (unlikely(!extra.type ||
 950                              extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 951                         if (net_ratelimit())
 952                                 dev_warn(dev, "Invalid extra type: %d\n",
 953                                          extra.type);
 954                         err = -EINVAL;
 955                 } else {
 956                         extras[extra.type - 1] = extra;
 957                 }
 958
 959                 skb = xennet_get_rx_skb(queue, cons);
 960                 ref = xennet_get_rx_ref(queue, cons);
 961                 xennet_move_rx_slot(queue, skb, ref);
 962         } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
 963
 964         xennet_set_rx_rsp_cons(queue, cons);
 965         return err;
 966 }
 967
 968 static u32 xennet_run_xdp(struct netfront_queue *queue, struct page *pdata,
 969                    struct xen_netif_rx_response *rx, struct bpf_prog *prog,
 970                    struct xdp_buff *xdp, bool *need_xdp_flush)
 971 {
 972         struct xdp_frame *xdpf;
 973         u32 len = rx->status;
 974         u32 act;
 975         int err;
 976
 977         xdp_init_buff(xdp, XEN_PAGE_SIZE - XDP_PACKET_HEADROOM,
 978                       &queue->xdp_rxq);
 979         xdp_prepare_buff(xdp, page_address(pdata), XDP_PACKET_HEADROOM,
 980                          len, false);
 981
 982         act = bpf_prog_run_xdp(prog, xdp);
 983         switch (act) {
 984         case XDP_TX:
 985                 get_page(pdata);
 986                 xdpf = xdp_convert_buff_to_frame(xdp);
 987                 err = xennet_xdp_xmit(queue->info->netdev, 1, &xdpf, 0);
 988                 if (unlikely(!err))
 989                         xdp_return_frame_rx_napi(xdpf);
 990                 else if (unlikely(err < 0))
 991                         trace_xdp_exception(queue->info->netdev, prog, act);
 992                 break;
 993         case XDP_REDIRECT:
 994                 get_page(pdata);
 995                 err = xdp_do_redirect(queue->info->netdev, xdp, prog);
 996                 *need_xdp_flush = true;
 997                 if (unlikely(err))
 998                         trace_xdp_exception(queue->info->netdev, prog, act);
 999                 break;
1000         case XDP_PASS:
1001         case XDP_DROP:
1002                 break;
1003
1004         case XDP_ABORTED:
1005                 trace_xdp_exception(queue->info->netdev, prog, act);
1006                 break;
1007
1008         default:
1009                 bpf_warn_invalid_xdp_action(queue->info->netdev, prog, act);
1010         }
1011
1012         return act;
1013 }
1014
1015 static int xennet_get_responses(struct netfront_queue *queue,
1016                                 struct netfront_rx_info *rinfo, RING_IDX rp,
1017                                 struct sk_buff_head *list,
1018                                 bool *need_xdp_flush)
1019 {
1020         struct xen_netif_rx_response *rx = &rinfo->rx, rx_local;
1021         int max = XEN_NETIF_NR_SLOTS_MIN + (rx->status <= RX_COPY_THRESHOLD);
1022         RING_IDX cons = queue->rx.rsp_cons;
1023         struct sk_buff *skb = xennet_get_rx_skb(queue, cons);
1024         struct xen_netif_extra_info *extras = rinfo->extras;
1025         grant_ref_t ref = xennet_get_rx_ref(queue, cons);
1026         struct device *dev = &queue->info->netdev->dev;
1027         struct bpf_prog *xdp_prog;
1028         struct xdp_buff xdp;
1029         int slots = 1;
1030         int err = 0;
1031         u32 verdict;
1032
1033         if (rx->flags & XEN_NETRXF_extra_info) {
1034                 err = xennet_get_extras(queue, extras, rp);
1035                 if (!err) {
1036                         if (extras[XEN_NETIF_EXTRA_TYPE_XDP - 1].type) {
1037                                 struct xen_netif_extra_info *xdp;
1038
1039                                 xdp = &extras[XEN_NETIF_EXTRA_TYPE_XDP - 1];
1040                                 rx->offset = xdp->u.xdp.headroom;
1041                         }
1042                 }
1043                 cons = queue->rx.rsp_cons;
1044         }
1045
1046         for (;;) {
1047                 /*
1048                  * This definitely indicates a bug, either in this driver or in
1049                  * the backend driver. In future this should flag the bad
1050                  * situation to the system controller to reboot the backend.
1051                  */
1052                 if (ref == INVALID_GRANT_REF) {
1053                         if (net_ratelimit())
1054                                 dev_warn(dev, "Bad rx response id %d.\n",
1055                                          rx->id);
1056                         err = -EINVAL;
1057                         goto next;
1058                 }
1059
1060                 if (unlikely(rx->status < 0 ||
1061                              rx->offset + rx->status > XEN_PAGE_SIZE)) {
1062                         if (net_ratelimit())
1063                                 dev_warn(dev, "rx->offset: %u, size: %d\n",
1064                                          rx->offset, rx->status);
1065                         xennet_move_rx_slot(queue, skb, ref);
1066                         err = -EINVAL;
1067                         goto next;
1068                 }
1069
1070                 if (!gnttab_end_foreign_access_ref(ref)) {
1071                         dev_alert(dev,
1072                                   "Grant still in use by backend domain\n");
1073                         queue->info->broken = true;
1074                         dev_alert(dev, "Disabled for further use\n");
1075                         return -EINVAL;
1076                 }
1077
1078                 gnttab_release_grant_reference(&queue->gref_rx_head, ref);
1079
1080                 rcu_read_lock();
1081                 xdp_prog = rcu_dereference(queue->xdp_prog);
1082                 if (xdp_prog) {
1083                         if (!(rx->flags & XEN_NETRXF_more_data)) {
1084                                 /* currently only a single page contains data */
1085                                 verdict = xennet_run_xdp(queue,
1086                                                          skb_frag_page(&skb_shinfo(skb)->frags[0]),
1087                                                          rx, xdp_prog, &xdp, need_xdp_flush);
1088                                 if (verdict != XDP_PASS)
1089                                         err = -EINVAL;
1090                         } else {
1091                                 /* drop the frame */
1092                                 err = -EINVAL;
1093                         }
1094                 }
1095                 rcu_read_unlock();
1096
1097                 __skb_queue_tail(list, skb);
1098
1099 next:
1100                 if (!(rx->flags & XEN_NETRXF_more_data))
1101                         break;
1102
1103                 if (cons + slots == rp) {
1104                         if (net_ratelimit())
1105                                 dev_warn(dev, "Need more slots\n");
1106                         err = -ENOENT;
1107                         break;
1108                 }
1109
1110                 RING_COPY_RESPONSE(&queue->rx, cons + slots, &rx_local);
1111                 rx = &rx_local;
1112                 skb = xennet_get_rx_skb(queue, cons + slots);
1113                 ref = xennet_get_rx_ref(queue, cons + slots);
1114                 slots++;
1115         }
1116
1117         if (unlikely(slots > max)) {
1118                 if (net_ratelimit())
1119                         dev_warn(dev, "Too many slots\n");
1120                 err = -E2BIG;
1121         }
1122
1123         if (unlikely(err))
1124                 xennet_set_rx_rsp_cons(queue, cons + slots);
1125
1126         return err;
1127 }
1128
1129 static int xennet_set_skb_gso(struct sk_buff *skb,
1130                               struct xen_netif_extra_info *gso)
1131 {
1132         if (!gso->u.gso.size) {
1133                 if (net_ratelimit())
1134                         pr_warn("GSO size must not be zero\n");
1135                 return -EINVAL;
1136         }
1137
1138         if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4 &&
1139             gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV6) {
1140                 if (net_ratelimit())
1141                         pr_warn("Bad GSO type %d\n", gso->u.gso.type);
1142                 return -EINVAL;
1143         }
1144
1145         skb_shinfo(skb)->gso_size = gso->u.gso.size;
1146         skb_shinfo(skb)->gso_type =
1147                 (gso->u.gso.type == XEN_NETIF_GSO_TYPE_TCPV4) ?
1148                 SKB_GSO_TCPV4 :
1149                 SKB_GSO_TCPV6;
1150
1151         /* Header must be checked, and gso_segs computed. */
1152         skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1153         skb_shinfo(skb)->gso_segs = 0;
1154
1155         return 0;
1156 }
1157
1158 static int xennet_fill_frags(struct netfront_queue *queue,
1159                              struct sk_buff *skb,
1160                              struct sk_buff_head *list)
1161 {
1162         RING_IDX cons = queue->rx.rsp_cons;
1163         struct sk_buff *nskb;
1164
1165         while ((nskb = __skb_dequeue(list))) {
1166                 struct xen_netif_rx_response rx;
1167                 skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0];
1168
1169                 RING_COPY_RESPONSE(&queue->rx, ++cons, &rx);
1170
1171                 if (skb_shinfo(skb)->nr_frags == MAX_SKB_FRAGS) {
1172                         unsigned int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
1173
1174                         BUG_ON(pull_to < skb_headlen(skb));
1175                         __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
1176                 }
1177                 if (unlikely(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) {
1178                         xennet_set_rx_rsp_cons(queue,
1179                                                ++cons + skb_queue_len(list));
1180                         kfree_skb(nskb);
1181                         return -ENOENT;
1182                 }
1183
1184                 skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
1185                                 skb_frag_page(nfrag),
1186                                 rx.offset, rx.status, PAGE_SIZE);
1187
1188                 skb_shinfo(nskb)->nr_frags = 0;
1189                 kfree_skb(nskb);
1190         }
1191
1192         xennet_set_rx_rsp_cons(queue, cons);
1193
1194         return 0;
1195 }
1196
1197 static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
1198 {
1199         bool recalculate_partial_csum = false;
1200
1201         /*
1202          * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1203          * peers can fail to set NETRXF_csum_blank when sending a GSO
1204          * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1205          * recalculate the partial checksum.
1206          */
1207         if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1208                 struct netfront_info *np = netdev_priv(dev);
1209                 atomic_inc(&np->rx_gso_checksum_fixup);
1210                 skb->ip_summed = CHECKSUM_PARTIAL;
1211                 recalculate_partial_csum = true;
1212         }
1213
1214         /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1215         if (skb->ip_summed != CHECKSUM_PARTIAL)
1216                 return 0;
1217
1218         return skb_checksum_setup(skb, recalculate_partial_csum);
1219 }
1220
1221 static int handle_incoming_queue(struct netfront_queue *queue,
1222                                  struct sk_buff_head *rxq)
1223 {
1224         struct netfront_stats *rx_stats = this_cpu_ptr(queue->info->rx_stats);
1225         int packets_dropped = 0;
1226         struct sk_buff *skb;
1227
1228         while ((skb = __skb_dequeue(rxq)) != NULL) {
1229                 int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
1230
1231                 if (pull_to > skb_headlen(skb))
1232                         __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
1233
1234                 /* Ethernet work: Delayed to here as it peeks the header. */
1235                 skb->protocol = eth_type_trans(skb, queue->info->netdev);
1236                 skb_reset_network_header(skb);
1237
1238                 if (checksum_setup(queue->info->netdev, skb)) {
1239                         kfree_skb(skb);
1240                         packets_dropped++;
1241                         queue->info->netdev->stats.rx_errors++;
1242                         continue;
1243                 }
1244
1245                 u64_stats_update_begin(&rx_stats->syncp);
1246                 rx_stats->packets++;
1247                 rx_stats->bytes += skb->len;
1248                 u64_stats_update_end(&rx_stats->syncp);
1249
1250                 /* Pass it up. */
1251                 napi_gro_receive(&queue->napi, skb);
1252         }
1253
1254         return packets_dropped;
1255 }
1256
1257 static int xennet_poll(struct napi_struct *napi, int budget)
1258 {
1259         struct netfront_queue *queue = container_of(napi, struct netfront_queue, napi);
1260         struct net_device *dev = queue->info->netdev;
1261         struct sk_buff *skb;
1262         struct netfront_rx_info rinfo;
1263         struct xen_netif_rx_response *rx = &rinfo.rx;
1264         struct xen_netif_extra_info *extras = rinfo.extras;
1265         RING_IDX i, rp;
1266         int work_done;
1267         struct sk_buff_head rxq;
1268         struct sk_buff_head errq;
1269         struct sk_buff_head tmpq;
1270         int err;
1271         bool need_xdp_flush = false;
1272
1273         spin_lock(&queue->rx_lock);
1274
1275         skb_queue_head_init(&rxq);
1276         skb_queue_head_init(&errq);
1277         skb_queue_head_init(&tmpq);
1278
1279         rp = queue->rx.sring->rsp_prod;
1280         if (RING_RESPONSE_PROD_OVERFLOW(&queue->rx, rp)) {
1281                 dev_alert(&dev->dev, "Illegal number of responses %u\n",
1282                           rp - queue->rx.rsp_cons);
1283                 queue->info->broken = true;
1284                 spin_unlock(&queue->rx_lock);
1285                 return 0;
1286         }
1287         rmb(); /* Ensure we see queued responses up to 'rp'. */
1288
1289         i = queue->rx.rsp_cons;
1290         work_done = 0;
1291         while ((i != rp) && (work_done < budget)) {
1292                 RING_COPY_RESPONSE(&queue->rx, i, rx);
1293                 memset(extras, 0, sizeof(rinfo.extras));
1294
1295                 err = xennet_get_responses(queue, &rinfo, rp, &tmpq,
1296                                            &need_xdp_flush);
1297
1298                 if (unlikely(err)) {
1299                         if (queue->info->broken) {
1300                                 spin_unlock(&queue->rx_lock);
1301                                 return 0;
1302                         }
1303 err:
1304                         while ((skb = __skb_dequeue(&tmpq)))
1305                                 __skb_queue_tail(&errq, skb);
1306                         dev->stats.rx_errors++;
1307                         i = queue->rx.rsp_cons;
1308                         continue;
1309                 }
1310
1311                 skb = __skb_dequeue(&tmpq);
1312
1313                 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1314                         struct xen_netif_extra_info *gso;
1315                         gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1316
1317                         if (unlikely(xennet_set_skb_gso(skb, gso))) {
1318                                 __skb_queue_head(&tmpq, skb);
1319                                 xennet_set_rx_rsp_cons(queue,
1320                                                        queue->rx.rsp_cons +
1321                                                        skb_queue_len(&tmpq));
1322                                 goto err;
1323                         }
1324                 }
1325
1326                 NETFRONT_SKB_CB(skb)->pull_to = rx->status;
1327                 if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD)
1328                         NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD;
1329
1330                 skb_frag_off_set(&skb_shinfo(skb)->frags[0], rx->offset);
1331                 skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status);
1332                 skb->data_len = rx->status;
1333                 skb->len += rx->status;
1334
1335                 if (unlikely(xennet_fill_frags(queue, skb, &tmpq)))
1336                         goto err;
1337
1338                 if (rx->flags & XEN_NETRXF_csum_blank)
1339                         skb->ip_summed = CHECKSUM_PARTIAL;
1340                 else if (rx->flags & XEN_NETRXF_data_validated)
1341                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1342
1343                 __skb_queue_tail(&rxq, skb);
1344
1345                 i = queue->rx.rsp_cons + 1;
1346                 xennet_set_rx_rsp_cons(queue, i);
1347                 work_done++;
1348         }
1349         if (need_xdp_flush)
1350                 xdp_do_flush();
1351
1352         __skb_queue_purge(&errq);
1353
1354         work_done -= handle_incoming_queue(queue, &rxq);
1355
1356         xennet_alloc_rx_buffers(queue);
1357
1358         if (work_done < budget) {
1359                 int more_to_do = 0;
1360
1361                 napi_complete_done(napi, work_done);
1362
1363                 RING_FINAL_CHECK_FOR_RESPONSES(&queue->rx, more_to_do);
1364                 if (more_to_do)
1365                         napi_schedule(napi);
1366         }
1367
1368         spin_unlock(&queue->rx_lock);
1369
1370         return work_done;
1371 }
1372
1373 static int xennet_change_mtu(struct net_device *dev, int mtu)
1374 {
1375         int max = xennet_can_sg(dev) ? XEN_NETIF_MAX_TX_SIZE : ETH_DATA_LEN;
1376
1377         if (mtu > max)
1378                 return -EINVAL;
1379         dev->mtu = mtu;
1380         return 0;
1381 }
1382
1383 static void xennet_get_stats64(struct net_device *dev,
1384                                struct rtnl_link_stats64 *tot)
1385 {
1386         struct netfront_info *np = netdev_priv(dev);
1387         int cpu;
1388
1389         for_each_possible_cpu(cpu) {
1390                 struct netfront_stats *rx_stats = per_cpu_ptr(np->rx_stats, cpu);
1391                 struct netfront_stats *tx_stats = per_cpu_ptr(np->tx_stats, cpu);
1392                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
1393                 unsigned int start;
1394
1395                 do {
1396                         start = u64_stats_fetch_begin(&tx_stats->syncp);
1397                         tx_packets = tx_stats->packets;
1398                         tx_bytes = tx_stats->bytes;
1399                 } while (u64_stats_fetch_retry(&tx_stats->syncp, start));
1400
1401                 do {
1402                         start = u64_stats_fetch_begin(&rx_stats->syncp);
1403                         rx_packets = rx_stats->packets;
1404                         rx_bytes = rx_stats->bytes;
1405                 } while (u64_stats_fetch_retry(&rx_stats->syncp, start));
1406
1407                 tot->rx_packets += rx_packets;
1408                 tot->tx_packets += tx_packets;
1409                 tot->rx_bytes   += rx_bytes;
1410                 tot->tx_bytes   += tx_bytes;
1411         }
1412
1413         tot->rx_errors  = dev->stats.rx_errors;
1414         tot->tx_dropped = dev->stats.tx_dropped;
1415 }
1416
1417 static void xennet_release_tx_bufs(struct netfront_queue *queue)
1418 {
1419         struct sk_buff *skb;
1420         int i;
1421
1422         for (i = 0; i < NET_TX_RING_SIZE; i++) {
1423                 /* Skip over entries which are actually freelist references */
1424                 if (!queue->tx_skbs[i])
1425                         continue;
1426
1427                 skb = queue->tx_skbs[i];
1428                 queue->tx_skbs[i] = NULL;
1429                 get_page(queue->grant_tx_page[i]);
1430                 gnttab_end_foreign_access(queue->grant_tx_ref[i],
1431                                           queue->grant_tx_page[i]);
1432                 queue->grant_tx_page[i] = NULL;
1433                 queue->grant_tx_ref[i] = INVALID_GRANT_REF;
1434                 add_id_to_list(&queue->tx_skb_freelist, queue->tx_link, i);
1435                 dev_kfree_skb_irq(skb);
1436         }
1437 }
1438
1439 static void xennet_release_rx_bufs(struct netfront_queue *queue)
1440 {
1441         int id, ref;
1442
1443         spin_lock_bh(&queue->rx_lock);
1444
1445         for (id = 0; id < NET_RX_RING_SIZE; id++) {
1446                 struct sk_buff *skb;
1447                 struct page *page;
1448
1449                 skb = queue->rx_skbs[id];
1450                 if (!skb)
1451                         continue;
1452
1453                 ref = queue->grant_rx_ref[id];
1454                 if (ref == INVALID_GRANT_REF)
1455                         continue;
1456
1457                 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
1458
1459                 /* gnttab_end_foreign_access() needs a page ref until
1460                  * foreign access is ended (which may be deferred).
1461                  */
1462                 get_page(page);
1463                 gnttab_end_foreign_access(ref, page);
1464                 queue->grant_rx_ref[id] = INVALID_GRANT_REF;
1465
1466                 kfree_skb(skb);
1467         }
1468
1469         spin_unlock_bh(&queue->rx_lock);
1470 }
1471
1472 static netdev_features_t xennet_fix_features(struct net_device *dev,
1473         netdev_features_t features)
1474 {
1475         struct netfront_info *np = netdev_priv(dev);
1476
1477         if (features & NETIF_F_SG &&
1478             !xenbus_read_unsigned(np->xbdev->otherend, "feature-sg", 0))
1479                 features &= ~NETIF_F_SG;
1480
1481         if (features & NETIF_F_IPV6_CSUM &&
1482             !xenbus_read_unsigned(np->xbdev->otherend,
1483                                   "feature-ipv6-csum-offload", 0))
1484                 features &= ~NETIF_F_IPV6_CSUM;
1485
1486         if (features & NETIF_F_TSO &&
1487             !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv4", 0))
1488                 features &= ~NETIF_F_TSO;
1489
1490         if (features & NETIF_F_TSO6 &&
1491             !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv6", 0))
1492                 features &= ~NETIF_F_TSO6;
1493
1494         return features;
1495 }
1496
1497 static int xennet_set_features(struct net_device *dev,
1498         netdev_features_t features)
1499 {
1500         if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) {
1501                 netdev_info(dev, "Reducing MTU because no SG offload");
1502                 dev->mtu = ETH_DATA_LEN;
1503         }
1504
1505         return 0;
1506 }
1507
1508 static bool xennet_handle_tx(struct netfront_queue *queue, unsigned int *eoi)
1509 {
1510         unsigned long flags;
1511
1512         if (unlikely(queue->info->broken))
1513                 return false;
1514
1515         spin_lock_irqsave(&queue->tx_lock, flags);
1516         if (xennet_tx_buf_gc(queue))
1517                 *eoi = 0;
1518         spin_unlock_irqrestore(&queue->tx_lock, flags);
1519
1520         return true;
1521 }
1522
1523 static irqreturn_t xennet_tx_interrupt(int irq, void *dev_id)
1524 {
1525         unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS;
1526
1527         if (likely(xennet_handle_tx(dev_id, &eoiflag)))
1528                 xen_irq_lateeoi(irq, eoiflag);
1529
1530         return IRQ_HANDLED;
1531 }
1532
1533 static bool xennet_handle_rx(struct netfront_queue *queue, unsigned int *eoi)
1534 {
1535         unsigned int work_queued;
1536         unsigned long flags;
1537
1538         if (unlikely(queue->info->broken))
1539                 return false;
1540
1541         spin_lock_irqsave(&queue->rx_cons_lock, flags);
1542         work_queued = XEN_RING_NR_UNCONSUMED_RESPONSES(&queue->rx);
1543         if (work_queued > queue->rx_rsp_unconsumed) {
1544                 queue->rx_rsp_unconsumed = work_queued;
1545                 *eoi = 0;
1546         } else if (unlikely(work_queued < queue->rx_rsp_unconsumed)) {
1547                 const struct device *dev = &queue->info->netdev->dev;
1548
1549                 spin_unlock_irqrestore(&queue->rx_cons_lock, flags);
1550                 dev_alert(dev, "RX producer index going backwards\n");
1551                 dev_alert(dev, "Disabled for further use\n");
1552                 queue->info->broken = true;
1553                 return false;
1554         }
1555         spin_unlock_irqrestore(&queue->rx_cons_lock, flags);
1556
1557         if (likely(netif_carrier_ok(queue->info->netdev) && work_queued))
1558                 napi_schedule(&queue->napi);
1559
1560         return true;
1561 }
1562
1563 static irqreturn_t xennet_rx_interrupt(int irq, void *dev_id)
1564 {
1565         unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS;
1566
1567         if (likely(xennet_handle_rx(dev_id, &eoiflag)))
1568                 xen_irq_lateeoi(irq, eoiflag);
1569
1570         return IRQ_HANDLED;
1571 }
1572
1573 static irqreturn_t xennet_interrupt(int irq, void *dev_id)
1574 {
1575         unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS;
1576
1577         if (xennet_handle_tx(dev_id, &eoiflag) &&
1578             xennet_handle_rx(dev_id, &eoiflag))
1579                 xen_irq_lateeoi(irq, eoiflag);
1580
1581         return IRQ_HANDLED;
1582 }
1583
1584 #ifdef CONFIG_NET_POLL_CONTROLLER
1585 static void xennet_poll_controller(struct net_device *dev)
1586 {
1587         /* Poll each queue */
1588         struct netfront_info *info = netdev_priv(dev);
1589         unsigned int num_queues = dev->real_num_tx_queues;
1590         unsigned int i;
1591
1592         if (info->broken)
1593                 return;
1594
1595         for (i = 0; i < num_queues; ++i)
1596                 xennet_interrupt(0, &info->queues[i]);
1597 }
1598 #endif
1599
1600 #define NETBACK_XDP_HEADROOM_DISABLE    0
1601 #define NETBACK_XDP_HEADROOM_ENABLE     1
1602
1603 static int talk_to_netback_xdp(struct netfront_info *np, int xdp)
1604 {
1605         int err;
1606         unsigned short headroom;
1607
1608         headroom = xdp ? XDP_PACKET_HEADROOM : 0;
1609         err = xenbus_printf(XBT_NIL, np->xbdev->nodename,
1610                             "xdp-headroom", "%hu",
1611                             headroom);
1612         if (err)
1613                 pr_warn("Error writing xdp-headroom\n");
1614
1615         return err;
1616 }
1617
1618 static int xennet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1619                           struct netlink_ext_ack *extack)
1620 {
1621         unsigned long max_mtu = XEN_PAGE_SIZE - XDP_PACKET_HEADROOM;
1622         struct netfront_info *np = netdev_priv(dev);
1623         struct bpf_prog *old_prog;
1624         unsigned int i, err;
1625
1626         if (dev->mtu > max_mtu) {
1627                 netdev_warn(dev, "XDP requires MTU less than %lu\n", max_mtu);
1628                 return -EINVAL;
1629         }
1630
1631         if (!np->netback_has_xdp_headroom)
1632                 return 0;
1633
1634         xenbus_switch_state(np->xbdev, XenbusStateReconfiguring);
1635
1636         err = talk_to_netback_xdp(np, prog ? NETBACK_XDP_HEADROOM_ENABLE :
1637                                   NETBACK_XDP_HEADROOM_DISABLE);
1638         if (err)
1639                 return err;
1640
1641         /* avoid the race with XDP headroom adjustment */
1642         wait_event(module_wq,
1643                    xenbus_read_driver_state(np->xbdev->otherend) ==
1644                    XenbusStateReconfigured);
1645         np->netfront_xdp_enabled = true;
1646
1647         old_prog = rtnl_dereference(np->queues[0].xdp_prog);
1648
1649         if (prog)
1650                 bpf_prog_add(prog, dev->real_num_tx_queues);
1651
1652         for (i = 0; i < dev->real_num_tx_queues; ++i)
1653                 rcu_assign_pointer(np->queues[i].xdp_prog, prog);
1654
1655         if (old_prog)
1656                 for (i = 0; i < dev->real_num_tx_queues; ++i)
1657                         bpf_prog_put(old_prog);
1658
1659         xenbus_switch_state(np->xbdev, XenbusStateConnected);
1660
1661         return 0;
1662 }
1663
1664 static int xennet_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1665 {
1666         struct netfront_info *np = netdev_priv(dev);
1667
1668         if (np->broken)
1669                 return -ENODEV;
1670
1671         switch (xdp->command) {
1672         case XDP_SETUP_PROG:
1673                 return xennet_xdp_set(dev, xdp->prog, xdp->extack);
1674         default:
1675                 return -EINVAL;
1676         }
1677 }
1678
1679 static const struct net_device_ops xennet_netdev_ops = {
1680         .ndo_uninit          = xennet_uninit,
1681         .ndo_open            = xennet_open,
1682         .ndo_stop            = xennet_close,
1683         .ndo_start_xmit      = xennet_start_xmit,
1684         .ndo_change_mtu      = xennet_change_mtu,
1685         .ndo_get_stats64     = xennet_get_stats64,
1686         .ndo_set_mac_address = eth_mac_addr,
1687         .ndo_validate_addr   = eth_validate_addr,
1688         .ndo_fix_features    = xennet_fix_features,
1689         .ndo_set_features    = xennet_set_features,
1690         .ndo_select_queue    = xennet_select_queue,
1691         .ndo_bpf            = xennet_xdp,
1692         .ndo_xdp_xmit       = xennet_xdp_xmit,
1693 #ifdef CONFIG_NET_POLL_CONTROLLER
1694         .ndo_poll_controller = xennet_poll_controller,
1695 #endif
1696 };
1697
1698 static void xennet_free_netdev(struct net_device *netdev)
1699 {
1700         struct netfront_info *np = netdev_priv(netdev);
1701
1702         free_percpu(np->rx_stats);
1703         free_percpu(np->tx_stats);
1704         free_netdev(netdev);
1705 }
1706
1707 static struct net_device *xennet_create_dev(struct xenbus_device *dev)
1708 {
1709         int err;
1710         struct net_device *netdev;
1711         struct netfront_info *np;
1712
1713         netdev = alloc_etherdev_mq(sizeof(struct netfront_info), xennet_max_queues);
1714         if (!netdev)
1715                 return ERR_PTR(-ENOMEM);
1716
1717         np                   = netdev_priv(netdev);
1718         np->xbdev            = dev;
1719
1720         np->queues = NULL;
1721
1722         err = -ENOMEM;
1723         np->rx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1724         if (np->rx_stats == NULL)
1725                 goto exit;
1726         np->tx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1727         if (np->tx_stats == NULL)
1728                 goto exit;
1729
1730         netdev->netdev_ops      = &xennet_netdev_ops;
1731
1732         netdev->features        = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
1733                                   NETIF_F_GSO_ROBUST;
1734         netdev->hw_features     = NETIF_F_SG |
1735                                   NETIF_F_IPV6_CSUM |
1736                                   NETIF_F_TSO | NETIF_F_TSO6;
1737
1738         /*
1739          * Assume that all hw features are available for now. This set
1740          * will be adjusted by the call to netdev_update_features() in
1741          * xennet_connect() which is the earliest point where we can
1742          * negotiate with the backend regarding supported features.
1743          */
1744         netdev->features |= netdev->hw_features;
1745         netdev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
1746                                NETDEV_XDP_ACT_NDO_XMIT;
1747
1748         netdev->ethtool_ops = &xennet_ethtool_ops;
1749         netdev->min_mtu = ETH_MIN_MTU;
1750         netdev->max_mtu = XEN_NETIF_MAX_TX_SIZE;
1751         SET_NETDEV_DEV(netdev, &dev->dev);
1752
1753         np->netdev = netdev;
1754         np->netfront_xdp_enabled = false;
1755
1756         netif_carrier_off(netdev);
1757
1758         do {
1759                 xenbus_switch_state(dev, XenbusStateInitialising);
1760                 err = wait_event_timeout(module_wq,
1761                                  xenbus_read_driver_state(dev->otherend) !=
1762                                  XenbusStateClosed &&
1763                                  xenbus_read_driver_state(dev->otherend) !=
1764                                  XenbusStateUnknown, XENNET_TIMEOUT);
1765         } while (!err);
1766
1767         return netdev;
1768
1769  exit:
1770         xennet_free_netdev(netdev);
1771         return ERR_PTR(err);
1772 }
1773
1774 /*
1775  * Entry point to this code when a new device is created.  Allocate the basic
1776  * structures and the ring buffers for communication with the backend, and
1777  * inform the backend of the appropriate details for those.
1778  */
1779 static int netfront_probe(struct xenbus_device *dev,
1780                           const struct xenbus_device_id *id)
1781 {
1782         int err;
1783         struct net_device *netdev;
1784         struct netfront_info *info;
1785
1786         netdev = xennet_create_dev(dev);
1787         if (IS_ERR(netdev)) {
1788                 err = PTR_ERR(netdev);
1789                 xenbus_dev_fatal(dev, err, "creating netdev");
1790                 return err;
1791         }
1792
1793         info = netdev_priv(netdev);
1794         dev_set_drvdata(&dev->dev, info);
1795 #ifdef CONFIG_SYSFS
1796         info->netdev->sysfs_groups[0] = &xennet_dev_group;
1797 #endif
1798
1799         return 0;
1800 }
1801
1802 static void xennet_end_access(int ref, void *page)
1803 {
1804         /* This frees the page as a side-effect */
1805         if (ref != INVALID_GRANT_REF)
1806                 gnttab_end_foreign_access(ref, virt_to_page(page));
1807 }
1808
1809 static void xennet_disconnect_backend(struct netfront_info *info)
1810 {
1811         unsigned int i = 0;
1812         unsigned int num_queues = info->netdev->real_num_tx_queues;
1813
1814         netif_carrier_off(info->netdev);
1815
1816         for (i = 0; i < num_queues && info->queues; ++i) {
1817                 struct netfront_queue *queue = &info->queues[i];
1818
1819                 del_timer_sync(&queue->rx_refill_timer);
1820
1821                 if (queue->tx_irq && (queue->tx_irq == queue->rx_irq))
1822                         unbind_from_irqhandler(queue->tx_irq, queue);
1823                 if (queue->tx_irq && (queue->tx_irq != queue->rx_irq)) {
1824                         unbind_from_irqhandler(queue->tx_irq, queue);
1825                         unbind_from_irqhandler(queue->rx_irq, queue);
1826                 }
1827                 queue->tx_evtchn = queue->rx_evtchn = 0;
1828                 queue->tx_irq = queue->rx_irq = 0;
1829
1830                 if (netif_running(info->netdev))
1831                         napi_synchronize(&queue->napi);
1832
1833                 xennet_release_tx_bufs(queue);
1834                 xennet_release_rx_bufs(queue);
1835                 gnttab_free_grant_references(queue->gref_tx_head);
1836                 gnttab_free_grant_references(queue->gref_rx_head);
1837
1838                 /* End access and free the pages */
1839                 xennet_end_access(queue->tx_ring_ref, queue->tx.sring);
1840                 xennet_end_access(queue->rx_ring_ref, queue->rx.sring);
1841
1842                 queue->tx_ring_ref = INVALID_GRANT_REF;
1843                 queue->rx_ring_ref = INVALID_GRANT_REF;
1844                 queue->tx.sring = NULL;
1845                 queue->rx.sring = NULL;
1846
1847                 page_pool_destroy(queue->page_pool);
1848         }
1849 }
1850
1851 /*
1852  * We are reconnecting to the backend, due to a suspend/resume, or a backend
1853  * driver restart.  We tear down our netif structure and recreate it, but
1854  * leave the device-layer structures intact so that this is transparent to the
1855  * rest of the kernel.
1856  */
1857 static int netfront_resume(struct xenbus_device *dev)
1858 {
1859         struct netfront_info *info = dev_get_drvdata(&dev->dev);
1860
1861         dev_dbg(&dev->dev, "%s\n", dev->nodename);
1862
1863         netif_tx_lock_bh(info->netdev);
1864         netif_device_detach(info->netdev);
1865         netif_tx_unlock_bh(info->netdev);
1866
1867         xennet_disconnect_backend(info);
1868
1869         rtnl_lock();
1870         if (info->queues)
1871                 xennet_destroy_queues(info);
1872         rtnl_unlock();
1873
1874         return 0;
1875 }
1876
1877 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
1878 {
1879         char *s, *e, *macstr;
1880         int i;
1881
1882         macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
1883         if (IS_ERR(macstr))
1884                 return PTR_ERR(macstr);
1885
1886         for (i = 0; i < ETH_ALEN; i++) {
1887                 mac[i] = simple_strtoul(s, &e, 16);
1888                 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
1889                         kfree(macstr);
1890                         return -ENOENT;
1891                 }
1892                 s = e+1;
1893         }
1894
1895         kfree(macstr);
1896         return 0;
1897 }
1898
1899 static int setup_netfront_single(struct netfront_queue *queue)
1900 {
1901         int err;
1902
1903         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1904         if (err < 0)
1905                 goto fail;
1906
1907         err = bind_evtchn_to_irqhandler_lateeoi(queue->tx_evtchn,
1908                                                 xennet_interrupt, 0,
1909                                                 queue->info->netdev->name,
1910                                                 queue);
1911         if (err < 0)
1912                 goto bind_fail;
1913         queue->rx_evtchn = queue->tx_evtchn;
1914         queue->rx_irq = queue->tx_irq = err;
1915
1916         return 0;
1917
1918 bind_fail:
1919         xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1920         queue->tx_evtchn = 0;
1921 fail:
1922         return err;
1923 }
1924
1925 static int setup_netfront_split(struct netfront_queue *queue)
1926 {
1927         int err;
1928
1929         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1930         if (err < 0)
1931                 goto fail;
1932         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->rx_evtchn);
1933         if (err < 0)
1934                 goto alloc_rx_evtchn_fail;
1935
1936         snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
1937                  "%s-tx", queue->name);
1938         err = bind_evtchn_to_irqhandler_lateeoi(queue->tx_evtchn,
1939                                                 xennet_tx_interrupt, 0,
1940                                                 queue->tx_irq_name, queue);
1941         if (err < 0)
1942                 goto bind_tx_fail;
1943         queue->tx_irq = err;
1944
1945         snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
1946                  "%s-rx", queue->name);
1947         err = bind_evtchn_to_irqhandler_lateeoi(queue->rx_evtchn,
1948                                                 xennet_rx_interrupt, 0,
1949                                                 queue->rx_irq_name, queue);
1950         if (err < 0)
1951                 goto bind_rx_fail;
1952         queue->rx_irq = err;
1953
1954         return 0;
1955
1956 bind_rx_fail:
1957         unbind_from_irqhandler(queue->tx_irq, queue);
1958         queue->tx_irq = 0;
1959 bind_tx_fail:
1960         xenbus_free_evtchn(queue->info->xbdev, queue->rx_evtchn);
1961         queue->rx_evtchn = 0;
1962 alloc_rx_evtchn_fail:
1963         xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1964         queue->tx_evtchn = 0;
1965 fail:
1966         return err;
1967 }
1968
1969 static int setup_netfront(struct xenbus_device *dev,
1970                         struct netfront_queue *queue, unsigned int feature_split_evtchn)
1971 {
1972         struct xen_netif_tx_sring *txs;
1973         struct xen_netif_rx_sring *rxs;
1974         int err;
1975
1976         queue->tx_ring_ref = INVALID_GRANT_REF;
1977         queue->rx_ring_ref = INVALID_GRANT_REF;
1978         queue->rx.sring = NULL;
1979         queue->tx.sring = NULL;
1980
1981         err = xenbus_setup_ring(dev, GFP_NOIO | __GFP_HIGH, (void **)&txs,
1982                                 1, &queue->tx_ring_ref);
1983         if (err)
1984                 goto fail;
1985
1986         XEN_FRONT_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
1987
1988         err = xenbus_setup_ring(dev, GFP_NOIO | __GFP_HIGH, (void **)&rxs,
1989                                 1, &queue->rx_ring_ref);
1990         if (err)
1991                 goto fail;
1992
1993         XEN_FRONT_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
1994
1995         if (feature_split_evtchn)
1996                 err = setup_netfront_split(queue);
1997         /* setup single event channel if
1998          *  a) feature-split-event-channels == 0
1999          *  b) feature-split-event-channels == 1 but failed to setup
2000          */
2001         if (!feature_split_evtchn || err)
2002                 err = setup_netfront_single(queue);
2003
2004         if (err)
2005                 goto fail;
2006
2007         return 0;
2008
2009  fail:
2010         xenbus_teardown_ring((void **)&queue->rx.sring, 1, &queue->rx_ring_ref);
2011         xenbus_teardown_ring((void **)&queue->tx.sring, 1, &queue->tx_ring_ref);
2012
2013         return err;
2014 }
2015
2016 /* Queue-specific initialisation
2017  * This used to be done in xennet_create_dev() but must now
2018  * be run per-queue.
2019  */
2020 static int xennet_init_queue(struct netfront_queue *queue)
2021 {
2022         unsigned short i;
2023         int err = 0;
2024         char *devid;
2025
2026         spin_lock_init(&queue->tx_lock);
2027         spin_lock_init(&queue->rx_lock);
2028         spin_lock_init(&queue->rx_cons_lock);
2029
2030         timer_setup(&queue->rx_refill_timer, rx_refill_timeout, 0);
2031
2032         devid = strrchr(queue->info->xbdev->nodename, '/') + 1;
2033         snprintf(queue->name, sizeof(queue->name), "vif%s-q%u",
2034                  devid, queue->id);
2035
2036         /* Initialise tx_skb_freelist as a free chain containing every entry. */
2037         queue->tx_skb_freelist = 0;
2038         queue->tx_pend_queue = TX_LINK_NONE;
2039         for (i = 0; i < NET_TX_RING_SIZE; i++) {
2040                 queue->tx_link[i] = i + 1;
2041                 queue->grant_tx_ref[i] = INVALID_GRANT_REF;
2042                 queue->grant_tx_page[i] = NULL;
2043         }
2044         queue->tx_link[NET_TX_RING_SIZE - 1] = TX_LINK_NONE;
2045
2046         /* Clear out rx_skbs */
2047         for (i = 0; i < NET_RX_RING_SIZE; i++) {
2048                 queue->rx_skbs[i] = NULL;
2049                 queue->grant_rx_ref[i] = INVALID_GRANT_REF;
2050         }
2051
2052         /* A grant for every tx ring slot */
2053         if (gnttab_alloc_grant_references(NET_TX_RING_SIZE,
2054                                           &queue->gref_tx_head) < 0) {
2055                 pr_alert("can't alloc tx grant refs\n");
2056                 err = -ENOMEM;
2057                 goto exit;
2058         }
2059
2060         /* A grant for every rx ring slot */
2061         if (gnttab_alloc_grant_references(NET_RX_RING_SIZE,
2062                                           &queue->gref_rx_head) < 0) {
2063                 pr_alert("can't alloc rx grant refs\n");
2064                 err = -ENOMEM;
2065                 goto exit_free_tx;
2066         }
2067
2068         return 0;
2069
2070  exit_free_tx:
2071         gnttab_free_grant_references(queue->gref_tx_head);
2072  exit:
2073         return err;
2074 }
2075
2076 static int write_queue_xenstore_keys(struct netfront_queue *queue,
2077                            struct xenbus_transaction *xbt, int write_hierarchical)
2078 {
2079         /* Write the queue-specific keys into XenStore in the traditional
2080          * way for a single queue, or in a queue subkeys for multiple
2081          * queues.
2082          */
2083         struct xenbus_device *dev = queue->info->xbdev;
2084         int err;
2085         const char *message;
2086         char *path;
2087         size_t pathsize;
2088
2089         /* Choose the correct place to write the keys */
2090         if (write_hierarchical) {
2091                 pathsize = strlen(dev->nodename) + 10;
2092                 path = kzalloc(pathsize, GFP_KERNEL);
2093                 if (!path) {
2094                         err = -ENOMEM;
2095                         message = "out of memory while writing ring references";
2096                         goto error;
2097                 }
2098                 snprintf(path, pathsize, "%s/queue-%u",
2099                                 dev->nodename, queue->id);
2100         } else {
2101                 path = (char *)dev->nodename;
2102         }
2103
2104         /* Write ring references */
2105         err = xenbus_printf(*xbt, path, "tx-ring-ref", "%u",
2106                         queue->tx_ring_ref);
2107         if (err) {
2108                 message = "writing tx-ring-ref";
2109                 goto error;
2110         }
2111
2112         err = xenbus_printf(*xbt, path, "rx-ring-ref", "%u",
2113                         queue->rx_ring_ref);
2114         if (err) {
2115                 message = "writing rx-ring-ref";
2116                 goto error;
2117         }
2118
2119         /* Write event channels; taking into account both shared
2120          * and split event channel scenarios.
2121          */
2122         if (queue->tx_evtchn == queue->rx_evtchn) {
2123                 /* Shared event channel */
2124                 err = xenbus_printf(*xbt, path,
2125                                 "event-channel", "%u", queue->tx_evtchn);
2126                 if (err) {
2127                         message = "writing event-channel";
2128                         goto error;
2129                 }
2130         } else {
2131                 /* Split event channels */
2132                 err = xenbus_printf(*xbt, path,
2133                                 "event-channel-tx", "%u", queue->tx_evtchn);
2134                 if (err) {
2135                         message = "writing event-channel-tx";
2136                         goto error;
2137                 }
2138
2139                 err = xenbus_printf(*xbt, path,
2140                                 "event-channel-rx", "%u", queue->rx_evtchn);
2141                 if (err) {
2142                         message = "writing event-channel-rx";
2143                         goto error;
2144                 }
2145         }
2146
2147         if (write_hierarchical)
2148                 kfree(path);
2149         return 0;
2150
2151 error:
2152         if (write_hierarchical)
2153                 kfree(path);
2154         xenbus_dev_fatal(dev, err, "%s", message);
2155         return err;
2156 }
2157
2158
2159
2160 static int xennet_create_page_pool(struct netfront_queue *queue)
2161 {
2162         int err;
2163         struct page_pool_params pp_params = {
2164                 .order = 0,
2165                 .flags = 0,
2166                 .pool_size = NET_RX_RING_SIZE,
2167                 .nid = NUMA_NO_NODE,
2168                 .dev = &queue->info->netdev->dev,
2169                 .offset = XDP_PACKET_HEADROOM,
2170                 .max_len = XEN_PAGE_SIZE - XDP_PACKET_HEADROOM,
2171         };
2172
2173         queue->page_pool = page_pool_create(&pp_params);
2174         if (IS_ERR(queue->page_pool)) {
2175                 err = PTR_ERR(queue->page_pool);
2176                 queue->page_pool = NULL;
2177                 return err;
2178         }
2179
2180         err = xdp_rxq_info_reg(&queue->xdp_rxq, queue->info->netdev,
2181                                queue->id, 0);
2182         if (err) {
2183                 netdev_err(queue->info->netdev, "xdp_rxq_info_reg failed\n");
2184                 goto err_free_pp;
2185         }
2186
2187         err = xdp_rxq_info_reg_mem_model(&queue->xdp_rxq,
2188                                          MEM_TYPE_PAGE_POOL, queue->page_pool);
2189         if (err) {
2190                 netdev_err(queue->info->netdev, "xdp_rxq_info_reg_mem_model failed\n");
2191                 goto err_unregister_rxq;
2192         }
2193         return 0;
2194
2195 err_unregister_rxq:
2196         xdp_rxq_info_unreg(&queue->xdp_rxq);
2197 err_free_pp:
2198         page_pool_destroy(queue->page_pool);
2199         queue->page_pool = NULL;
2200         return err;
2201 }
2202
2203 static int xennet_create_queues(struct netfront_info *info,
2204                                 unsigned int *num_queues)
2205 {
2206         unsigned int i;
2207         int ret;
2208
2209         info->queues = kcalloc(*num_queues, sizeof(struct netfront_queue),
2210                                GFP_KERNEL);
2211         if (!info->queues)
2212                 return -ENOMEM;
2213
2214         for (i = 0; i < *num_queues; i++) {
2215                 struct netfront_queue *queue = &info->queues[i];
2216
2217                 queue->id = i;
2218                 queue->info = info;
2219
2220                 ret = xennet_init_queue(queue);
2221                 if (ret < 0) {
2222                         dev_warn(&info->xbdev->dev,
2223                                  "only created %d queues\n", i);
2224                         *num_queues = i;
2225                         break;
2226                 }
2227
2228                 /* use page pool recycling instead of buddy allocator */
2229                 ret = xennet_create_page_pool(queue);
2230                 if (ret < 0) {
2231                         dev_err(&info->xbdev->dev, "can't allocate page pool\n");
2232                         *num_queues = i;
2233                         return ret;
2234                 }
2235
2236                 netif_napi_add(queue->info->netdev, &queue->napi, xennet_poll);
2237                 if (netif_running(info->netdev))
2238                         napi_enable(&queue->napi);
2239         }
2240
2241         netif_set_real_num_tx_queues(info->netdev, *num_queues);
2242
2243         if (*num_queues == 0) {
2244                 dev_err(&info->xbdev->dev, "no queues\n");
2245                 return -EINVAL;
2246         }
2247         return 0;
2248 }
2249
2250 /* Common code used when first setting up, and when resuming. */
2251 static int talk_to_netback(struct xenbus_device *dev,
2252                            struct netfront_info *info)
2253 {
2254         const char *message;
2255         struct xenbus_transaction xbt;
2256         int err;
2257         unsigned int feature_split_evtchn;
2258         unsigned int i = 0;
2259         unsigned int max_queues = 0;
2260         struct netfront_queue *queue = NULL;
2261         unsigned int num_queues = 1;
2262         u8 addr[ETH_ALEN];
2263
2264         info->netdev->irq = 0;
2265
2266         /* Check if backend is trusted. */
2267         info->bounce = !xennet_trusted ||
2268                        !xenbus_read_unsigned(dev->nodename, "trusted", 1);
2269
2270         /* Check if backend supports multiple queues */
2271         max_queues = xenbus_read_unsigned(info->xbdev->otherend,
2272                                           "multi-queue-max-queues", 1);
2273         num_queues = min(max_queues, xennet_max_queues);
2274
2275         /* Check feature-split-event-channels */
2276         feature_split_evtchn = xenbus_read_unsigned(info->xbdev->otherend,
2277                                         "feature-split-event-channels", 0);
2278
2279         /* Read mac addr. */
2280         err = xen_net_read_mac(dev, addr);
2281         if (err) {
2282                 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
2283                 goto out_unlocked;
2284         }
2285         eth_hw_addr_set(info->netdev, addr);
2286
2287         info->netback_has_xdp_headroom = xenbus_read_unsigned(info->xbdev->otherend,
2288                                                               "feature-xdp-headroom", 0);
2289         if (info->netback_has_xdp_headroom) {
2290                 /* set the current xen-netfront xdp state */
2291                 err = talk_to_netback_xdp(info, info->netfront_xdp_enabled ?
2292                                           NETBACK_XDP_HEADROOM_ENABLE :
2293                                           NETBACK_XDP_HEADROOM_DISABLE);
2294                 if (err)
2295                         goto out_unlocked;
2296         }
2297
2298         rtnl_lock();
2299         if (info->queues)
2300                 xennet_destroy_queues(info);
2301
2302         /* For the case of a reconnect reset the "broken" indicator. */
2303         info->broken = false;
2304
2305         err = xennet_create_queues(info, &num_queues);
2306         if (err < 0) {
2307                 xenbus_dev_fatal(dev, err, "creating queues");
2308                 kfree(info->queues);
2309                 info->queues = NULL;
2310                 goto out;
2311         }
2312         rtnl_unlock();
2313
2314         /* Create shared ring, alloc event channel -- for each queue */
2315         for (i = 0; i < num_queues; ++i) {
2316                 queue = &info->queues[i];
2317                 err = setup_netfront(dev, queue, feature_split_evtchn);
2318                 if (err)
2319                         goto destroy_ring;
2320         }
2321
2322 again:
2323         err = xenbus_transaction_start(&xbt);
2324         if (err) {
2325                 xenbus_dev_fatal(dev, err, "starting transaction");
2326                 goto destroy_ring;
2327         }
2328
2329         if (xenbus_exists(XBT_NIL,
2330                           info->xbdev->otherend, "multi-queue-max-queues")) {
2331                 /* Write the number of queues */
2332                 err = xenbus_printf(xbt, dev->nodename,
2333                                     "multi-queue-num-queues", "%u", num_queues);
2334                 if (err) {
2335                         message = "writing multi-queue-num-queues";
2336                         goto abort_transaction_no_dev_fatal;
2337                 }
2338         }
2339
2340         if (num_queues == 1) {
2341                 err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
2342                 if (err)
2343                         goto abort_transaction_no_dev_fatal;
2344         } else {
2345                 /* Write the keys for each queue */
2346                 for (i = 0; i < num_queues; ++i) {
2347                         queue = &info->queues[i];
2348                         err = write_queue_xenstore_keys(queue, &xbt, 1); /* hierarchical */
2349                         if (err)
2350                                 goto abort_transaction_no_dev_fatal;
2351                 }
2352         }
2353
2354         /* The remaining keys are not queue-specific */
2355         err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
2356                             1);
2357         if (err) {
2358                 message = "writing request-rx-copy";
2359                 goto abort_transaction;
2360         }
2361
2362         err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
2363         if (err) {
2364                 message = "writing feature-rx-notify";
2365                 goto abort_transaction;
2366         }
2367
2368         err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
2369         if (err) {
2370                 message = "writing feature-sg";
2371                 goto abort_transaction;
2372         }
2373
2374         err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
2375         if (err) {
2376                 message = "writing feature-gso-tcpv4";
2377                 goto abort_transaction;
2378         }
2379
2380         err = xenbus_write(xbt, dev->nodename, "feature-gso-tcpv6", "1");
2381         if (err) {
2382                 message = "writing feature-gso-tcpv6";
2383                 goto abort_transaction;
2384         }
2385
2386         err = xenbus_write(xbt, dev->nodename, "feature-ipv6-csum-offload",
2387                            "1");
2388         if (err) {
2389                 message = "writing feature-ipv6-csum-offload";
2390                 goto abort_transaction;
2391         }
2392
2393         err = xenbus_transaction_end(xbt, 0);
2394         if (err) {
2395                 if (err == -EAGAIN)
2396                         goto again;
2397                 xenbus_dev_fatal(dev, err, "completing transaction");
2398                 goto destroy_ring;
2399         }
2400
2401         return 0;
2402
2403  abort_transaction:
2404         xenbus_dev_fatal(dev, err, "%s", message);
2405 abort_transaction_no_dev_fatal:
2406         xenbus_transaction_end(xbt, 1);
2407  destroy_ring:
2408         xennet_disconnect_backend(info);
2409         rtnl_lock();
2410         xennet_destroy_queues(info);
2411  out:
2412         rtnl_unlock();
2413 out_unlocked:
2414         device_unregister(&dev->dev);
2415         return err;
2416 }
2417
2418 static int xennet_connect(struct net_device *dev)
2419 {
2420         struct netfront_info *np = netdev_priv(dev);
2421         unsigned int num_queues = 0;
2422         int err;
2423         unsigned int j = 0;
2424         struct netfront_queue *queue = NULL;
2425
2426         if (!xenbus_read_unsigned(np->xbdev->otherend, "feature-rx-copy", 0)) {
2427                 dev_info(&dev->dev,
2428                          "backend does not support copying receive path\n");
2429                 return -ENODEV;
2430         }
2431
2432         err = talk_to_netback(np->xbdev, np);
2433         if (err)
2434                 return err;
2435         if (np->netback_has_xdp_headroom)
2436                 pr_info("backend supports XDP headroom\n");
2437         if (np->bounce)
2438                 dev_info(&np->xbdev->dev,
2439                          "bouncing transmitted data to zeroed pages\n");
2440
2441         /* talk_to_netback() sets the correct number of queues */
2442         num_queues = dev->real_num_tx_queues;
2443
2444         if (dev->reg_state == NETREG_UNINITIALIZED) {
2445                 err = register_netdev(dev);
2446                 if (err) {
2447                         pr_warn("%s: register_netdev err=%d\n", __func__, err);
2448                         device_unregister(&np->xbdev->dev);
2449                         return err;
2450                 }
2451         }
2452
2453         rtnl_lock();
2454         netdev_update_features(dev);
2455         rtnl_unlock();
2456
2457         /*
2458          * All public and private state should now be sane.  Get
2459          * ready to start sending and receiving packets and give the driver
2460          * domain a kick because we've probably just requeued some
2461          * packets.
2462          */
2463         netif_tx_lock_bh(np->netdev);
2464         netif_device_attach(np->netdev);
2465         netif_tx_unlock_bh(np->netdev);
2466
2467         netif_carrier_on(np->netdev);
2468         for (j = 0; j < num_queues; ++j) {
2469                 queue = &np->queues[j];
2470
2471                 notify_remote_via_irq(queue->tx_irq);
2472                 if (queue->tx_irq != queue->rx_irq)
2473                         notify_remote_via_irq(queue->rx_irq);
2474
2475                 spin_lock_bh(&queue->rx_lock);
2476                 xennet_alloc_rx_buffers(queue);
2477                 spin_unlock_bh(&queue->rx_lock);
2478         }
2479
2480         return 0;
2481 }
2482
2483 /*
2484  * Callback received when the backend's state changes.
2485  */
2486 static void netback_changed(struct xenbus_device *dev,
2487                             enum xenbus_state backend_state)
2488 {
2489         struct netfront_info *np = dev_get_drvdata(&dev->dev);
2490         struct net_device *netdev = np->netdev;
2491
2492         dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
2493
2494         wake_up_all(&module_wq);
2495
2496         switch (backend_state) {
2497         case XenbusStateInitialising:
2498         case XenbusStateInitialised:
2499         case XenbusStateReconfiguring:
2500         case XenbusStateReconfigured:
2501         case XenbusStateUnknown:
2502                 break;
2503
2504         case XenbusStateInitWait:
2505                 if (dev->state != XenbusStateInitialising)
2506                         break;
2507                 if (xennet_connect(netdev) != 0)
2508                         break;
2509                 xenbus_switch_state(dev, XenbusStateConnected);
2510                 break;
2511
2512         case XenbusStateConnected:
2513                 netdev_notify_peers(netdev);
2514                 break;
2515
2516         case XenbusStateClosed:
2517                 if (dev->state == XenbusStateClosed)
2518                         break;
2519                 fallthrough;    /* Missed the backend's CLOSING state */
2520         case XenbusStateClosing:
2521                 xenbus_frontend_closed(dev);
2522                 break;
2523         }
2524 }
2525
2526 static const struct xennet_stat {
2527         char name[ETH_GSTRING_LEN];
2528         u16 offset;
2529 } xennet_stats[] = {
2530         {
2531                 "rx_gso_checksum_fixup",
2532                 offsetof(struct netfront_info, rx_gso_checksum_fixup)
2533         },
2534 };
2535
2536 static int xennet_get_sset_count(struct net_device *dev, int string_set)
2537 {
2538         switch (string_set) {
2539         case ETH_SS_STATS:
2540                 return ARRAY_SIZE(xennet_stats);
2541         default:
2542                 return -EINVAL;
2543         }
2544 }
2545
2546 static void xennet_get_ethtool_stats(struct net_device *dev,
2547                                      struct ethtool_stats *stats, u64 * data)
2548 {
2549         void *np = netdev_priv(dev);
2550         int i;
2551
2552         for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2553                 data[i] = atomic_read((atomic_t *)(np + xennet_stats[i].offset));
2554 }
2555
2556 static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data)
2557 {
2558         int i;
2559
2560         switch (stringset) {
2561         case ETH_SS_STATS:
2562                 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2563                         memcpy(data + i * ETH_GSTRING_LEN,
2564                                xennet_stats[i].name, ETH_GSTRING_LEN);
2565                 break;
2566         }
2567 }
2568
2569 static const struct ethtool_ops xennet_ethtool_ops =
2570 {
2571         .get_link = ethtool_op_get_link,
2572
2573         .get_sset_count = xennet_get_sset_count,
2574         .get_ethtool_stats = xennet_get_ethtool_stats,
2575         .get_strings = xennet_get_strings,
2576         .get_ts_info = ethtool_op_get_ts_info,
2577 };
2578
2579 #ifdef CONFIG_SYSFS
2580 static ssize_t show_rxbuf(struct device *dev,
2581                           struct device_attribute *attr, char *buf)
2582 {
2583         return sprintf(buf, "%lu\n", NET_RX_RING_SIZE);
2584 }
2585
2586 static ssize_t store_rxbuf(struct device *dev,
2587                            struct device_attribute *attr,
2588                            const char *buf, size_t len)
2589 {
2590         char *endp;
2591
2592         if (!capable(CAP_NET_ADMIN))
2593                 return -EPERM;
2594
2595         simple_strtoul(buf, &endp, 0);
2596         if (endp == buf)
2597                 return -EBADMSG;
2598
2599         /* rxbuf_min and rxbuf_max are no longer configurable. */
2600
2601         return len;
2602 }
2603
2604 static DEVICE_ATTR(rxbuf_min, 0644, show_rxbuf, store_rxbuf);
2605 static DEVICE_ATTR(rxbuf_max, 0644, show_rxbuf, store_rxbuf);
2606 static DEVICE_ATTR(rxbuf_cur, 0444, show_rxbuf, NULL);
2607
2608 static struct attribute *xennet_dev_attrs[] = {
2609         &dev_attr_rxbuf_min.attr,
2610         &dev_attr_rxbuf_max.attr,
2611         &dev_attr_rxbuf_cur.attr,
2612         NULL
2613 };
2614
2615 static const struct attribute_group xennet_dev_group = {
2616         .attrs = xennet_dev_attrs
2617 };
2618 #endif /* CONFIG_SYSFS */
2619
2620 static void xennet_bus_close(struct xenbus_device *dev)
2621 {
2622         int ret;
2623
2624         if (xenbus_read_driver_state(dev->otherend) == XenbusStateClosed)
2625                 return;
2626         do {
2627                 xenbus_switch_state(dev, XenbusStateClosing);
2628                 ret = wait_event_timeout(module_wq,
2629                                    xenbus_read_driver_state(dev->otherend) ==
2630                                    XenbusStateClosing ||
2631                                    xenbus_read_driver_state(dev->otherend) ==
2632                                    XenbusStateClosed ||
2633                                    xenbus_read_driver_state(dev->otherend) ==
2634                                    XenbusStateUnknown,
2635                                    XENNET_TIMEOUT);
2636         } while (!ret);
2637
2638         if (xenbus_read_driver_state(dev->otherend) == XenbusStateClosed)
2639                 return;
2640
2641         do {
2642                 xenbus_switch_state(dev, XenbusStateClosed);
2643                 ret = wait_event_timeout(module_wq,
2644                                    xenbus_read_driver_state(dev->otherend) ==
2645                                    XenbusStateClosed ||
2646                                    xenbus_read_driver_state(dev->otherend) ==
2647                                    XenbusStateUnknown,
2648                                    XENNET_TIMEOUT);
2649         } while (!ret);
2650 }
2651
2652 static void xennet_remove(struct xenbus_device *dev)
2653 {
2654         struct netfront_info *info = dev_get_drvdata(&dev->dev);
2655
2656         xennet_bus_close(dev);
2657         xennet_disconnect_backend(info);
2658
2659         if (info->netdev->reg_state == NETREG_REGISTERED)
2660                 unregister_netdev(info->netdev);
2661
2662         if (info->queues) {
2663                 rtnl_lock();
2664                 xennet_destroy_queues(info);
2665                 rtnl_unlock();
2666         }
2667         xennet_free_netdev(info->netdev);
2668 }
2669
2670 static const struct xenbus_device_id netfront_ids[] = {
2671         { "vif" },
2672         { "" }
2673 };
2674
2675 static struct xenbus_driver netfront_driver = {
2676         .ids = netfront_ids,
2677         .probe = netfront_probe,
2678         .remove = xennet_remove,
2679         .resume = netfront_resume,
2680         .otherend_changed = netback_changed,
2681 };
2682
2683 static int __init netif_init(void)
2684 {
2685         if (!xen_domain())
2686                 return -ENODEV;
2687
2688         if (!xen_has_pv_nic_devices())
2689                 return -ENODEV;
2690
2691         pr_info("Initialising Xen virtual ethernet driver\n");
2692
2693         /* Allow as many queues as there are CPUs inut max. 8 if user has not
2694          * specified a value.
2695          */
2696         if (xennet_max_queues == 0)
2697                 xennet_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
2698                                           num_online_cpus());
2699
2700         return xenbus_register_frontend(&netfront_driver);
2701 }
2702 module_init(netif_init);
2703
2704
2705 static void __exit netif_exit(void)
2706 {
2707         xenbus_unregister_driver(&netfront_driver);
2708 }
2709 module_exit(netif_exit);
2710
2711 MODULE_DESCRIPTION("Xen virtual network device frontend");
2712 MODULE_LICENSE("GPL");
2713 MODULE_ALIAS("xen:vif");
2714 MODULE_ALIAS("xennet");