drivers/net/xen-netback/netback.c

   1 /*
   2  * Back-end of the driver for virtual network devices. This portion of the
   3  * driver exports a 'unified' network-device interface that can be accessed
   4  * by any operating system that implements a compatible front end. A
   5  * reference front-end implementation can be found in:
   6  *  drivers/net/xen-netfront.c
   7  *
   8  * Copyright (c) 2002-2005, K A Fraser
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License version 2
  12  * as published by the Free Software Foundation; or, when distributed
  13  * separately from the Linux kernel or incorporated into other
  14  * software packages, subject to the following license:
  15  *
  16  * Permission is hereby granted, free of charge, to any person obtaining a copy
  17  * of this source file (the "Software"), to deal in the Software without
  18  * restriction, including without limitation the rights to use, copy, modify,
  19  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  20  * and to permit persons to whom the Software is furnished to do so, subject to
  21  * the following conditions:
  22  *
  23  * The above copyright notice and this permission notice shall be included in
  24  * all copies or substantial portions of the Software.
  25  *
  26  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  27  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  28  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  29  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  30  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  31  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  32  * IN THE SOFTWARE.
  33  */
  34
  35 #include "common.h"
  36
  37 #include <linux/kthread.h>
  38 #include <linux/if_vlan.h>
  39 #include <linux/udp.h>
  40 #include <linux/highmem.h>
  41
  42 #include <net/tcp.h>
  43
  44 #include <xen/xen.h>
  45 #include <xen/events.h>
  46 #include <xen/interface/memory.h>
  47 #include <xen/page.h>
  48
  49 #include <asm/xen/hypercall.h>
  50
  51 /* Provide an option to disable split event channels at load time as
  52  * event channels are limited resource. Split event channels are
  53  * enabled by default.
  54  */
  55 bool separate_tx_rx_irq = true;
  56 module_param(separate_tx_rx_irq, bool, 0644);
  57
  58 /* The time that packets can stay on the guest Rx internal queue
  59  * before they are dropped.
  60  */
  61 unsigned int rx_drain_timeout_msecs = 10000;
  62 module_param(rx_drain_timeout_msecs, uint, 0444);
  63
  64 /* The length of time before the frontend is considered unresponsive
  65  * because it isn't providing Rx slots.
  66  */
  67 unsigned int rx_stall_timeout_msecs = 60000;
  68 module_param(rx_stall_timeout_msecs, uint, 0444);
  69
  70 #define MAX_QUEUES_DEFAULT 8
  71 unsigned int xenvif_max_queues;
  72 module_param_named(max_queues, xenvif_max_queues, uint, 0644);
  73 MODULE_PARM_DESC(max_queues,
  74                  "Maximum number of queues per virtual interface");
  75
  76 /*
  77  * This is the maximum slots a skb can have. If a guest sends a skb
  78  * which exceeds this limit it is considered malicious.
  79  */
  80 #define FATAL_SKB_SLOTS_DEFAULT 20
  81 static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
  82 module_param(fatal_skb_slots, uint, 0444);
  83
  84 /* The amount to copy out of the first guest Tx slot into the skb's
  85  * linear area.  If the first slot has more data, it will be mapped
  86  * and put into the first frag.
  87  *
  88  * This is sized to avoid pulling headers from the frags for most
  89  * TCP/IP packets.
  90  */
  91 #define XEN_NETBACK_TX_COPY_LEN 128
  92
  93
  94 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
  95                                u8 status);
  96
  97 static void make_tx_response(struct xenvif_queue *queue,
  98                              struct xen_netif_tx_request *txp,
  99                              s8       st);
 100 static void push_tx_responses(struct xenvif_queue *queue);
 101
 102 static inline int tx_work_todo(struct xenvif_queue *queue);
 103
 104 static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
 105                                              u16      id,
 106                                              s8       st,
 107                                              u16      offset,
 108                                              u16      size,
 109                                              u16      flags);
 110
 111 static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
 112                                        u16 idx)
 113 {
 114         return page_to_pfn(queue->mmap_pages[idx]);
 115 }
 116
 117 static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
 118                                          u16 idx)
 119 {
 120         return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
 121 }
 122
 123 #define callback_param(vif, pending_idx) \
 124         (vif->pending_tx_info[pending_idx].callback_struct)
 125
 126 /* Find the containing VIF's structure from a pointer in pending_tx_info array
 127  */
 128 static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
 129 {
 130         u16 pending_idx = ubuf->desc;
 131         struct pending_tx_info *temp =
 132                 container_of(ubuf, struct pending_tx_info, callback_struct);
 133         return container_of(temp - pending_idx,
 134                             struct xenvif_queue,
 135                             pending_tx_info[0]);
 136 }
 137
 138 static u16 frag_get_pending_idx(skb_frag_t *frag)
 139 {
 140         return (u16)frag->page_offset;
 141 }
 142
 143 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
 144 {
 145         frag->page_offset = pending_idx;
 146 }
 147
 148 static inline pending_ring_idx_t pending_index(unsigned i)
 149 {
 150         return i & (MAX_PENDING_REQS-1);
 151 }
 152
 153 static int xenvif_rx_ring_slots_needed(struct xenvif *vif)
 154 {
 155         if (vif->gso_mask)
 156                 return DIV_ROUND_UP(vif->dev->gso_max_size, XEN_PAGE_SIZE) + 1;
 157         else
 158                 return DIV_ROUND_UP(vif->dev->mtu, XEN_PAGE_SIZE);
 159 }
 160
 161 static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
 162 {
 163         RING_IDX prod, cons;
 164         int needed;
 165
 166         needed = xenvif_rx_ring_slots_needed(queue->vif);
 167
 168         do {
 169                 prod = queue->rx.sring->req_prod;
 170                 cons = queue->rx.req_cons;
 171
 172                 if (prod - cons >= needed)
 173                         return true;
 174
 175                 queue->rx.sring->req_event = prod + 1;
 176
 177                 /* Make sure event is visible before we check prod
 178                  * again.
 179                  */
 180                 mb();
 181         } while (queue->rx.sring->req_prod != prod);
 182
 183         return false;
 184 }
 185
 186 void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb)
 187 {
 188         unsigned long flags;
 189
 190         spin_lock_irqsave(&queue->rx_queue.lock, flags);
 191
 192         __skb_queue_tail(&queue->rx_queue, skb);
 193
 194         queue->rx_queue_len += skb->len;
 195         if (queue->rx_queue_len > queue->rx_queue_max)
 196                 netif_tx_stop_queue(netdev_get_tx_queue(queue->vif->dev, queue->id));
 197
 198         spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
 199 }
 200
 201 static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue)
 202 {
 203         struct sk_buff *skb;
 204
 205         spin_lock_irq(&queue->rx_queue.lock);
 206
 207         skb = __skb_dequeue(&queue->rx_queue);
 208         if (skb)
 209                 queue->rx_queue_len -= skb->len;
 210
 211         spin_unlock_irq(&queue->rx_queue.lock);
 212
 213         return skb;
 214 }
 215
 216 static void xenvif_rx_queue_maybe_wake(struct xenvif_queue *queue)
 217 {
 218         spin_lock_irq(&queue->rx_queue.lock);
 219
 220         if (queue->rx_queue_len < queue->rx_queue_max)
 221                 netif_tx_wake_queue(netdev_get_tx_queue(queue->vif->dev, queue->id));
 222
 223         spin_unlock_irq(&queue->rx_queue.lock);
 224 }
 225
 226
 227 static void xenvif_rx_queue_purge(struct xenvif_queue *queue)
 228 {
 229         struct sk_buff *skb;
 230         while ((skb = xenvif_rx_dequeue(queue)) != NULL)
 231                 kfree_skb(skb);
 232 }
 233
 234 static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue)
 235 {
 236         struct sk_buff *skb;
 237
 238         for(;;) {
 239                 skb = skb_peek(&queue->rx_queue);
 240                 if (!skb)
 241                         break;
 242                 if (time_before(jiffies, XENVIF_RX_CB(skb)->expires))
 243                         break;
 244                 xenvif_rx_dequeue(queue);
 245                 kfree_skb(skb);
 246         }
 247 }
 248
 249 struct netrx_pending_operations {
 250         unsigned copy_prod, copy_cons;
 251         unsigned meta_prod, meta_cons;
 252         struct gnttab_copy *copy;
 253         struct xenvif_rx_meta *meta;
 254         int copy_off;
 255         grant_ref_t copy_gref;
 256 };
 257
 258 static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif_queue *queue,
 259                                                  struct netrx_pending_operations *npo)
 260 {
 261         struct xenvif_rx_meta *meta;
 262         struct xen_netif_rx_request req;
 263
 264         RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req);
 265
 266         meta = npo->meta + npo->meta_prod++;
 267         meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
 268         meta->gso_size = 0;
 269         meta->size = 0;
 270         meta->id = req.id;
 271
 272         npo->copy_off = 0;
 273         npo->copy_gref = req.gref;
 274
 275         return meta;
 276 }
 277
 278 struct gop_frag_copy {
 279         struct xenvif_queue *queue;
 280         struct netrx_pending_operations *npo;
 281         struct xenvif_rx_meta *meta;
 282         int head;
 283         int gso_type;
 284
 285         struct page *page;
 286 };
 287
 288 static void xenvif_setup_copy_gop(unsigned long gfn,
 289                                   unsigned int offset,
 290                                   unsigned int *len,
 291                                   struct gop_frag_copy *info)
 292 {
 293         struct gnttab_copy *copy_gop;
 294         struct xen_page_foreign *foreign;
 295         /* Convenient aliases */
 296         struct xenvif_queue *queue = info->queue;
 297         struct netrx_pending_operations *npo = info->npo;
 298         struct page *page = info->page;
 299
 300         BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
 301
 302         if (npo->copy_off == MAX_BUFFER_OFFSET)
 303                 info->meta = get_next_rx_buffer(queue, npo);
 304
 305         if (npo->copy_off + *len > MAX_BUFFER_OFFSET)
 306                 *len = MAX_BUFFER_OFFSET - npo->copy_off;
 307
 308         copy_gop = npo->copy + npo->copy_prod++;
 309         copy_gop->flags = GNTCOPY_dest_gref;
 310         copy_gop->len = *len;
 311
 312         foreign = xen_page_foreign(page);
 313         if (foreign) {
 314                 copy_gop->source.domid = foreign->domid;
 315                 copy_gop->source.u.ref = foreign->gref;
 316                 copy_gop->flags |= GNTCOPY_source_gref;
 317         } else {
 318                 copy_gop->source.domid = DOMID_SELF;
 319                 copy_gop->source.u.gmfn = gfn;
 320         }
 321         copy_gop->source.offset = offset;
 322
 323         copy_gop->dest.domid = queue->vif->domid;
 324         copy_gop->dest.offset = npo->copy_off;
 325         copy_gop->dest.u.ref = npo->copy_gref;
 326
 327         npo->copy_off += *len;
 328         info->meta->size += *len;
 329
 330         /* Leave a gap for the GSO descriptor. */
 331         if (info->head && ((1 << info->gso_type) & queue->vif->gso_mask))
 332                 queue->rx.req_cons++;
 333
 334         info->head = 0; /* There must be something in this buffer now */
 335 }
 336
 337 static void xenvif_gop_frag_copy_grant(unsigned long gfn,
 338                                        unsigned offset,
 339                                        unsigned int len,
 340                                        void *data)
 341 {
 342         unsigned int bytes;
 343
 344         while (len) {
 345                 bytes = len;
 346                 xenvif_setup_copy_gop(gfn, offset, &bytes, data);
 347                 offset += bytes;
 348                 len -= bytes;
 349         }
 350 }
 351
 352 /*
 353  * Set up the grant operations for this fragment. If it's a flipping
 354  * interface, we also set up the unmap request from here.
 355  */
 356 static void xenvif_gop_frag_copy(struct xenvif_queue *queue, struct sk_buff *skb,
 357                                  struct netrx_pending_operations *npo,
 358                                  struct page *page, unsigned long size,
 359                                  unsigned long offset, int *head)
 360 {
 361         struct gop_frag_copy info = {
 362                 .queue = queue,
 363                 .npo = npo,
 364                 .head = *head,
 365                 .gso_type = XEN_NETIF_GSO_TYPE_NONE,
 366         };
 367         unsigned long bytes;
 368
 369         if (skb_is_gso(skb)) {
 370                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 371                         info.gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
 372                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 373                         info.gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
 374         }
 375
 376         /* Data must not cross a page boundary. */
 377         BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
 378
 379         info.meta = npo->meta + npo->meta_prod - 1;
 380
 381         /* Skip unused frames from start of page */
 382         page += offset >> PAGE_SHIFT;
 383         offset &= ~PAGE_MASK;
 384
 385         while (size > 0) {
 386                 BUG_ON(offset >= PAGE_SIZE);
 387
 388                 bytes = PAGE_SIZE - offset;
 389                 if (bytes > size)
 390                         bytes = size;
 391
 392                 info.page = page;
 393                 gnttab_foreach_grant_in_range(page, offset, bytes,
 394                                               xenvif_gop_frag_copy_grant,
 395                                               &info);
 396                 size -= bytes;
 397                 offset = 0;
 398
 399                 /* Next page */
 400                 if (size) {
 401                         BUG_ON(!PageCompound(page));
 402                         page++;
 403                 }
 404         }
 405
 406         *head = info.head;
 407 }
 408
 409 /*
 410  * Prepare an SKB to be transmitted to the frontend.
 411  *
 412  * This function is responsible for allocating grant operations, meta
 413  * structures, etc.
 414  *
 415  * It returns the number of meta structures consumed. The number of
 416  * ring slots used is always equal to the number of meta slots used
 417  * plus the number of GSO descriptors used. Currently, we use either
 418  * zero GSO descriptors (for non-GSO packets) or one descriptor (for
 419  * frontend-side LRO).
 420  */
 421 static int xenvif_gop_skb(struct sk_buff *skb,
 422                           struct netrx_pending_operations *npo,
 423                           struct xenvif_queue *queue)
 424 {
 425         struct xenvif *vif = netdev_priv(skb->dev);
 426         int nr_frags = skb_shinfo(skb)->nr_frags;
 427         int i;
 428         struct xen_netif_rx_request req;
 429         struct xenvif_rx_meta *meta;
 430         unsigned char *data;
 431         int head = 1;
 432         int old_meta_prod;
 433         int gso_type;
 434
 435         old_meta_prod = npo->meta_prod;
 436
 437         gso_type = XEN_NETIF_GSO_TYPE_NONE;
 438         if (skb_is_gso(skb)) {
 439                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 440                         gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
 441                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 442                         gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
 443         }
 444
 445         /* Set up a GSO prefix descriptor, if necessary */
 446         if ((1 << gso_type) & vif->gso_prefix_mask) {
 447                 RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req);
 448                 meta = npo->meta + npo->meta_prod++;
 449                 meta->gso_type = gso_type;
 450                 meta->gso_size = skb_shinfo(skb)->gso_size;
 451                 meta->size = 0;
 452                 meta->id = req.id;
 453         }
 454
 455         RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req);
 456         meta = npo->meta + npo->meta_prod++;
 457
 458         if ((1 << gso_type) & vif->gso_mask) {
 459                 meta->gso_type = gso_type;
 460                 meta->gso_size = skb_shinfo(skb)->gso_size;
 461         } else {
 462                 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
 463                 meta->gso_size = 0;
 464         }
 465
 466         meta->size = 0;
 467         meta->id = req.id;
 468         npo->copy_off = 0;
 469         npo->copy_gref = req.gref;
 470
 471         data = skb->data;
 472         while (data < skb_tail_pointer(skb)) {
 473                 unsigned int offset = offset_in_page(data);
 474                 unsigned int len = PAGE_SIZE - offset;
 475
 476                 if (data + len > skb_tail_pointer(skb))
 477                         len = skb_tail_pointer(skb) - data;
 478
 479                 xenvif_gop_frag_copy(queue, skb, npo,
 480                                      virt_to_page(data), len, offset, &head);
 481                 data += len;
 482         }
 483
 484         for (i = 0; i < nr_frags; i++) {
 485                 xenvif_gop_frag_copy(queue, skb, npo,
 486                                      skb_frag_page(&skb_shinfo(skb)->frags[i]),
 487                                      skb_frag_size(&skb_shinfo(skb)->frags[i]),
 488                                      skb_shinfo(skb)->frags[i].page_offset,
 489                                      &head);
 490         }
 491
 492         return npo->meta_prod - old_meta_prod;
 493 }
 494
 495 /*
 496  * This is a twin to xenvif_gop_skb.  Assume that xenvif_gop_skb was
 497  * used to set up the operations on the top of
 498  * netrx_pending_operations, which have since been done.  Check that
 499  * they didn't give any errors and advance over them.
 500  */
 501 static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots,
 502                             struct netrx_pending_operations *npo)
 503 {
 504         struct gnttab_copy     *copy_op;
 505         int status = XEN_NETIF_RSP_OKAY;
 506         int i;
 507
 508         for (i = 0; i < nr_meta_slots; i++) {
 509                 copy_op = npo->copy + npo->copy_cons++;
 510                 if (copy_op->status != GNTST_okay) {
 511                         netdev_dbg(vif->dev,
 512                                    "Bad status %d from copy to DOM%d.\n",
 513                                    copy_op->status, vif->domid);
 514                         status = XEN_NETIF_RSP_ERROR;
 515                 }
 516         }
 517
 518         return status;
 519 }
 520
 521 static void xenvif_add_frag_responses(struct xenvif_queue *queue, int status,
 522                                       struct xenvif_rx_meta *meta,
 523                                       int nr_meta_slots)
 524 {
 525         int i;
 526         unsigned long offset;
 527
 528         /* No fragments used */
 529         if (nr_meta_slots <= 1)
 530                 return;
 531
 532         nr_meta_slots--;
 533
 534         for (i = 0; i < nr_meta_slots; i++) {
 535                 int flags;
 536                 if (i == nr_meta_slots - 1)
 537                         flags = 0;
 538                 else
 539                         flags = XEN_NETRXF_more_data;
 540
 541                 offset = 0;
 542                 make_rx_response(queue, meta[i].id, status, offset,
 543                                  meta[i].size, flags);
 544         }
 545 }
 546
 547 void xenvif_kick_thread(struct xenvif_queue *queue)
 548 {
 549         wake_up(&queue->wq);
 550 }
 551
 552 static void xenvif_rx_action(struct xenvif_queue *queue)
 553 {
 554         s8 status;
 555         u16 flags;
 556         struct xen_netif_rx_response *resp;
 557         struct sk_buff_head rxq;
 558         struct sk_buff *skb;
 559         LIST_HEAD(notify);
 560         int ret;
 561         unsigned long offset;
 562         bool need_to_notify = false;
 563
 564         struct netrx_pending_operations npo = {
 565                 .copy  = queue->grant_copy_op,
 566                 .meta  = queue->meta,
 567         };
 568
 569         skb_queue_head_init(&rxq);
 570
 571         while (xenvif_rx_ring_slots_available(queue)
 572                && (skb = xenvif_rx_dequeue(queue)) != NULL) {
 573                 queue->last_rx_time = jiffies;
 574
 575                 XENVIF_RX_CB(skb)->meta_slots_used = xenvif_gop_skb(skb, &npo, queue);
 576
 577                 __skb_queue_tail(&rxq, skb);
 578         }
 579
 580         BUG_ON(npo.meta_prod > ARRAY_SIZE(queue->meta));
 581
 582         if (!npo.copy_prod)
 583                 goto done;
 584
 585         BUG_ON(npo.copy_prod > MAX_GRANT_COPY_OPS);
 586         gnttab_batch_copy(queue->grant_copy_op, npo.copy_prod);
 587
 588         while ((skb = __skb_dequeue(&rxq)) != NULL) {
 589
 590                 if ((1 << queue->meta[npo.meta_cons].gso_type) &
 591                     queue->vif->gso_prefix_mask) {
 592                         resp = RING_GET_RESPONSE(&queue->rx,
 593                                                  queue->rx.rsp_prod_pvt++);
 594
 595                         resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
 596
 597                         resp->offset = queue->meta[npo.meta_cons].gso_size;
 598                         resp->id = queue->meta[npo.meta_cons].id;
 599                         resp->status = XENVIF_RX_CB(skb)->meta_slots_used;
 600
 601                         npo.meta_cons++;
 602                         XENVIF_RX_CB(skb)->meta_slots_used--;
 603                 }
 604
 605
 606                 queue->stats.tx_bytes += skb->len;
 607                 queue->stats.tx_packets++;
 608
 609                 status = xenvif_check_gop(queue->vif,
 610                                           XENVIF_RX_CB(skb)->meta_slots_used,
 611                                           &npo);
 612
 613                 if (XENVIF_RX_CB(skb)->meta_slots_used == 1)
 614                         flags = 0;
 615                 else
 616                         flags = XEN_NETRXF_more_data;
 617
 618                 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
 619                         flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
 620                 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
 621                         /* remote but checksummed. */
 622                         flags |= XEN_NETRXF_data_validated;
 623
 624                 offset = 0;
 625                 resp = make_rx_response(queue, queue->meta[npo.meta_cons].id,
 626                                         status, offset,
 627                                         queue->meta[npo.meta_cons].size,
 628                                         flags);
 629
 630                 if ((1 << queue->meta[npo.meta_cons].gso_type) &
 631                     queue->vif->gso_mask) {
 632                         struct xen_netif_extra_info *gso =
 633                                 (struct xen_netif_extra_info *)
 634                                 RING_GET_RESPONSE(&queue->rx,
 635                                                   queue->rx.rsp_prod_pvt++);
 636
 637                         resp->flags |= XEN_NETRXF_extra_info;
 638
 639                         gso->u.gso.type = queue->meta[npo.meta_cons].gso_type;
 640                         gso->u.gso.size = queue->meta[npo.meta_cons].gso_size;
 641                         gso->u.gso.pad = 0;
 642                         gso->u.gso.features = 0;
 643
 644                         gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
 645                         gso->flags = 0;
 646                 }
 647
 648                 xenvif_add_frag_responses(queue, status,
 649                                           queue->meta + npo.meta_cons + 1,
 650                                           XENVIF_RX_CB(skb)->meta_slots_used);
 651
 652                 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, ret);
 653
 654                 need_to_notify |= !!ret;
 655
 656                 npo.meta_cons += XENVIF_RX_CB(skb)->meta_slots_used;
 657                 dev_kfree_skb(skb);
 658         }
 659
 660 done:
 661         if (need_to_notify)
 662                 notify_remote_via_irq(queue->rx_irq);
 663 }
 664
 665 void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
 666 {
 667         int more_to_do;
 668
 669         RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
 670
 671         if (more_to_do)
 672                 napi_schedule(&queue->napi);
 673         else if (xenvif_atomic_fetch_andnot(NETBK_TX_EOI | NETBK_COMMON_EOI,
 674                                      &queue->eoi_pending) &
 675                  (NETBK_TX_EOI | NETBK_COMMON_EOI))
 676                 xen_irq_lateeoi(queue->tx_irq, 0);
 677 }
 678
 679 static void tx_add_credit(struct xenvif_queue *queue)
 680 {
 681         unsigned long max_burst, max_credit;
 682
 683         /*
 684          * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
 685          * Otherwise the interface can seize up due to insufficient credit.
 686          */
 687         max_burst = max(131072UL, queue->credit_bytes);
 688
 689         /* Take care that adding a new chunk of credit doesn't wrap to zero. */
 690         max_credit = queue->remaining_credit + queue->credit_bytes;
 691         if (max_credit < queue->remaining_credit)
 692                 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
 693
 694         queue->remaining_credit = min(max_credit, max_burst);
 695         queue->rate_limited = false;
 696 }
 697
 698 void xenvif_tx_credit_callback(unsigned long data)
 699 {
 700         struct xenvif_queue *queue = (struct xenvif_queue *)data;
 701         tx_add_credit(queue);
 702         xenvif_napi_schedule_or_enable_events(queue);
 703 }
 704
 705 static void xenvif_tx_err(struct xenvif_queue *queue,
 706                           struct xen_netif_tx_request *txp, RING_IDX end)
 707 {
 708         RING_IDX cons = queue->tx.req_cons;
 709         unsigned long flags;
 710
 711         do {
 712                 spin_lock_irqsave(&queue->response_lock, flags);
 713                 make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR);
 714                 push_tx_responses(queue);
 715                 spin_unlock_irqrestore(&queue->response_lock, flags);
 716                 if (cons == end)
 717                         break;
 718                 RING_COPY_REQUEST(&queue->tx, cons++, txp);
 719         } while (1);
 720         queue->tx.req_cons = cons;
 721 }
 722
 723 static void xenvif_fatal_tx_err(struct xenvif *vif)
 724 {
 725         netdev_err(vif->dev, "fatal error; disabling device\n");
 726         vif->disabled = true;
 727         /* Disable the vif from queue 0's kthread */
 728         if (vif->queues)
 729                 xenvif_kick_thread(&vif->queues[0]);
 730 }
 731
 732 static int xenvif_count_requests(struct xenvif_queue *queue,
 733                                  struct xen_netif_tx_request *first,
 734                                  struct xen_netif_tx_request *txp,
 735                                  int work_to_do)
 736 {
 737         RING_IDX cons = queue->tx.req_cons;
 738         int slots = 0;
 739         int drop_err = 0;
 740         int more_data;
 741
 742         if (!(first->flags & XEN_NETTXF_more_data))
 743                 return 0;
 744
 745         do {
 746                 struct xen_netif_tx_request dropped_tx = { 0 };
 747
 748                 if (slots >= work_to_do) {
 749                         netdev_err(queue->vif->dev,
 750                                    "Asked for %d slots but exceeds this limit\n",
 751                                    work_to_do);
 752                         xenvif_fatal_tx_err(queue->vif);
 753                         return -ENODATA;
 754                 }
 755
 756                 /* This guest is really using too many slots and
 757                  * considered malicious.
 758                  */
 759                 if (unlikely(slots >= fatal_skb_slots)) {
 760                         netdev_err(queue->vif->dev,
 761                                    "Malicious frontend using %d slots, threshold %u\n",
 762                                    slots, fatal_skb_slots);
 763                         xenvif_fatal_tx_err(queue->vif);
 764                         return -E2BIG;
 765                 }
 766
 767                 /* Xen network protocol had implicit dependency on
 768                  * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
 769                  * the historical MAX_SKB_FRAGS value 18 to honor the
 770                  * same behavior as before. Any packet using more than
 771                  * 18 slots but less than fatal_skb_slots slots is
 772                  * dropped
 773                  */
 774                 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
 775                         if (net_ratelimit())
 776                                 netdev_dbg(queue->vif->dev,
 777                                            "Too many slots (%d) exceeding limit (%d), dropping packet\n",
 778                                            slots, XEN_NETBK_LEGACY_SLOTS_MAX);
 779                         drop_err = -E2BIG;
 780                 }
 781
 782                 if (drop_err)
 783                         txp = &dropped_tx;
 784
 785                 RING_COPY_REQUEST(&queue->tx, cons + slots, txp);
 786
 787                 /* If the guest submitted a frame >= 64 KiB then
 788                  * first->size overflowed and following slots will
 789                  * appear to be larger than the frame.
 790                  *
 791                  * This cannot be fatal error as there are buggy
 792                  * frontends that do this.
 793                  *
 794                  * Consume all slots and drop the packet.
 795                  */
 796                 if (!drop_err && txp->size > first->size) {
 797                         if (net_ratelimit())
 798                                 netdev_dbg(queue->vif->dev,
 799                                            "Invalid tx request, slot size %u > remaining size %u\n",
 800                                            txp->size, first->size);
 801                         drop_err = -EIO;
 802                 }
 803
 804                 first->size -= txp->size;
 805                 slots++;
 806
 807                 if (unlikely((txp->offset + txp->size) > XEN_PAGE_SIZE)) {
 808                         netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n",
 809                                  txp->offset, txp->size);
 810                         xenvif_fatal_tx_err(queue->vif);
 811                         return -EINVAL;
 812                 }
 813
 814                 more_data = txp->flags & XEN_NETTXF_more_data;
 815
 816                 if (!drop_err)
 817                         txp++;
 818
 819         } while (more_data);
 820
 821         if (drop_err) {
 822                 xenvif_tx_err(queue, first, cons + slots);
 823                 return drop_err;
 824         }
 825
 826         return slots;
 827 }
 828
 829
 830 struct xenvif_tx_cb {
 831         u16 pending_idx;
 832 };
 833
 834 #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
 835
 836 static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
 837                                           u16 pending_idx,
 838                                           struct xen_netif_tx_request *txp,
 839                                           struct gnttab_map_grant_ref *mop)
 840 {
 841         queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
 842         gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
 843                           GNTMAP_host_map | GNTMAP_readonly,
 844                           txp->gref, queue->vif->domid);
 845
 846         memcpy(&queue->pending_tx_info[pending_idx].req, txp,
 847                sizeof(*txp));
 848 }
 849
 850 static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
 851 {
 852         struct sk_buff *skb =
 853                 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
 854                           GFP_ATOMIC | __GFP_NOWARN);
 855         if (unlikely(skb == NULL))
 856                 return NULL;
 857
 858         /* Packets passed to netif_rx() must have some headroom. */
 859         skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
 860
 861         /* Initialize it here to avoid later surprises */
 862         skb_shinfo(skb)->destructor_arg = NULL;
 863
 864         return skb;
 865 }
 866
 867 static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
 868                                                         struct sk_buff *skb,
 869                                                         struct xen_netif_tx_request *txp,
 870                                                         struct gnttab_map_grant_ref *gop,
 871                                                         unsigned int frag_overflow,
 872                                                         struct sk_buff *nskb)
 873 {
 874         struct skb_shared_info *shinfo = skb_shinfo(skb);
 875         skb_frag_t *frags = shinfo->frags;
 876         u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
 877         int start;
 878         pending_ring_idx_t index;
 879         unsigned int nr_slots;
 880
 881         nr_slots = shinfo->nr_frags;
 882
 883         /* Skip first skb fragment if it is on same page as header fragment. */
 884         start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
 885
 886         for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
 887              shinfo->nr_frags++, txp++, gop++) {
 888                 index = pending_index(queue->pending_cons++);
 889                 pending_idx = queue->pending_ring[index];
 890                 xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
 891                 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
 892         }
 893
 894         if (frag_overflow) {
 895
 896                 shinfo = skb_shinfo(nskb);
 897                 frags = shinfo->frags;
 898
 899                 for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
 900                      shinfo->nr_frags++, txp++, gop++) {
 901                         index = pending_index(queue->pending_cons++);
 902                         pending_idx = queue->pending_ring[index];
 903                         xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
 904                         frag_set_pending_idx(&frags[shinfo->nr_frags],
 905                                              pending_idx);
 906                 }
 907
 908                 skb_shinfo(skb)->frag_list = nskb;
 909         }
 910
 911         return gop;
 912 }
 913
 914 static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
 915                                            u16 pending_idx,
 916                                            grant_handle_t handle)
 917 {
 918         if (unlikely(queue->grant_tx_handle[pending_idx] !=
 919                      NETBACK_INVALID_HANDLE)) {
 920                 netdev_err(queue->vif->dev,
 921                            "Trying to overwrite active handle! pending_idx: 0x%x\n",
 922                            pending_idx);
 923                 BUG();
 924         }
 925         queue->grant_tx_handle[pending_idx] = handle;
 926 }
 927
 928 static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
 929                                              u16 pending_idx)
 930 {
 931         if (unlikely(queue->grant_tx_handle[pending_idx] ==
 932                      NETBACK_INVALID_HANDLE)) {
 933                 netdev_err(queue->vif->dev,
 934                            "Trying to unmap invalid handle! pending_idx: 0x%x\n",
 935                            pending_idx);
 936                 BUG();
 937         }
 938         queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
 939 }
 940
 941 static int xenvif_tx_check_gop(struct xenvif_queue *queue,
 942                                struct sk_buff *skb,
 943                                struct gnttab_map_grant_ref **gopp_map,
 944                                struct gnttab_copy **gopp_copy)
 945 {
 946         struct gnttab_map_grant_ref *gop_map = *gopp_map;
 947         u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
 948         /* This always points to the shinfo of the skb being checked, which
 949          * could be either the first or the one on the frag_list
 950          */
 951         struct skb_shared_info *shinfo = skb_shinfo(skb);
 952         /* If this is non-NULL, we are currently checking the frag_list skb, and
 953          * this points to the shinfo of the first one
 954          */
 955         struct skb_shared_info *first_shinfo = NULL;
 956         int nr_frags = shinfo->nr_frags;
 957         const bool sharedslot = nr_frags &&
 958                                 frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
 959         int i, err;
 960
 961         /* Check status of header. */
 962         err = (*gopp_copy)->status;
 963         if (unlikely(err)) {
 964                 if (net_ratelimit())
 965                         netdev_dbg(queue->vif->dev,
 966                                    "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
 967                                    (*gopp_copy)->status,
 968                                    pending_idx,
 969                                    (*gopp_copy)->source.u.ref);
 970                 /* The first frag might still have this slot mapped */
 971                 if (!sharedslot)
 972                         xenvif_idx_release(queue, pending_idx,
 973                                            XEN_NETIF_RSP_ERROR);
 974         }
 975         (*gopp_copy)++;
 976
 977 check_frags:
 978         for (i = 0; i < nr_frags; i++, gop_map++) {
 979                 int j, newerr;
 980
 981                 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
 982
 983                 /* Check error status: if okay then remember grant handle. */
 984                 newerr = gop_map->status;
 985
 986                 if (likely(!newerr)) {
 987                         xenvif_grant_handle_set(queue,
 988                                                 pending_idx,
 989                                                 gop_map->handle);
 990                         /* Had a previous error? Invalidate this fragment. */
 991                         if (unlikely(err)) {
 992                                 xenvif_idx_unmap(queue, pending_idx);
 993                                 /* If the mapping of the first frag was OK, but
 994                                  * the header's copy failed, and they are
 995                                  * sharing a slot, send an error
 996                                  */
 997                                 if (i == 0 && !first_shinfo && sharedslot)
 998                                         xenvif_idx_release(queue, pending_idx,
 999                                                            XEN_NETIF_RSP_ERROR);
1000                                 else
1001                                         xenvif_idx_release(queue, pending_idx,
1002                                                            XEN_NETIF_RSP_OKAY);
1003                         }
1004                         continue;
1005                 }
1006
1007                 /* Error on this fragment: respond to client with an error. */
1008                 if (net_ratelimit())
1009                         netdev_dbg(queue->vif->dev,
1010                                    "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
1011                                    i,
1012                                    gop_map->status,
1013                                    pending_idx,
1014                                    gop_map->ref);
1015
1016                 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
1017
1018                 /* Not the first error? Preceding frags already invalidated. */
1019                 if (err)
1020                         continue;
1021
1022                 /* First error: if the header haven't shared a slot with the
1023                  * first frag, release it as well.
1024                  */
1025                 if (!sharedslot)
1026                         xenvif_idx_release(queue,
1027                                            XENVIF_TX_CB(skb)->pending_idx,
1028                                            XEN_NETIF_RSP_OKAY);
1029
1030                 /* Invalidate preceding fragments of this skb. */
1031                 for (j = 0; j < i; j++) {
1032                         pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
1033                         xenvif_idx_unmap(queue, pending_idx);
1034                         xenvif_idx_release(queue, pending_idx,
1035                                            XEN_NETIF_RSP_OKAY);
1036                 }
1037
1038                 /* And if we found the error while checking the frag_list, unmap
1039                  * the first skb's frags
1040                  */
1041                 if (first_shinfo) {
1042                         for (j = 0; j < first_shinfo->nr_frags; j++) {
1043                                 pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
1044                                 xenvif_idx_unmap(queue, pending_idx);
1045                                 xenvif_idx_release(queue, pending_idx,
1046                                                    XEN_NETIF_RSP_OKAY);
1047                         }
1048                 }
1049
1050                 /* Remember the error: invalidate all subsequent fragments. */
1051                 err = newerr;
1052         }
1053
1054         if (skb_has_frag_list(skb) && !first_shinfo) {
1055                 first_shinfo = skb_shinfo(skb);
1056                 shinfo = skb_shinfo(skb_shinfo(skb)->frag_list);
1057                 nr_frags = shinfo->nr_frags;
1058
1059                 goto check_frags;
1060         }
1061
1062         *gopp_map = gop_map;
1063         return err;
1064 }
1065
1066 static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
1067 {
1068         struct skb_shared_info *shinfo = skb_shinfo(skb);
1069         int nr_frags = shinfo->nr_frags;
1070         int i;
1071         u16 prev_pending_idx = INVALID_PENDING_IDX;
1072
1073         for (i = 0; i < nr_frags; i++) {
1074                 skb_frag_t *frag = shinfo->frags + i;
1075                 struct xen_netif_tx_request *txp;
1076                 struct page *page;
1077                 u16 pending_idx;
1078
1079                 pending_idx = frag_get_pending_idx(frag);
1080
1081                 /* If this is not the first frag, chain it to the previous*/
1082                 if (prev_pending_idx == INVALID_PENDING_IDX)
1083                         skb_shinfo(skb)->destructor_arg =
1084                                 &callback_param(queue, pending_idx);
1085                 else
1086                         callback_param(queue, prev_pending_idx).ctx =
1087                                 &callback_param(queue, pending_idx);
1088
1089                 callback_param(queue, pending_idx).ctx = NULL;
1090                 prev_pending_idx = pending_idx;
1091
1092                 txp = &queue->pending_tx_info[pending_idx].req;
1093                 page = virt_to_page(idx_to_kaddr(queue, pending_idx));
1094                 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
1095                 skb->len += txp->size;
1096                 skb->data_len += txp->size;
1097                 skb->truesize += txp->size;
1098
1099                 /* Take an extra reference to offset network stack's put_page */
1100                 get_page(queue->mmap_pages[pending_idx]);
1101         }
1102 }
1103
1104 static int xenvif_get_extras(struct xenvif_queue *queue,
1105                                 struct xen_netif_extra_info *extras,
1106                                 int work_to_do)
1107 {
1108         struct xen_netif_extra_info extra;
1109         RING_IDX cons = queue->tx.req_cons;
1110
1111         do {
1112                 if (unlikely(work_to_do-- <= 0)) {
1113                         netdev_err(queue->vif->dev, "Missing extra info\n");
1114                         xenvif_fatal_tx_err(queue->vif);
1115                         return -EBADR;
1116                 }
1117
1118                 RING_COPY_REQUEST(&queue->tx, cons, &extra);
1119                 if (unlikely(!extra.type ||
1120                              extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1121                         queue->tx.req_cons = ++cons;
1122                         netdev_err(queue->vif->dev,
1123                                    "Invalid extra type: %d\n", extra.type);
1124                         xenvif_fatal_tx_err(queue->vif);
1125                         return -EINVAL;
1126                 }
1127
1128                 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1129                 queue->tx.req_cons = ++cons;
1130         } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1131
1132         return work_to_do;
1133 }
1134
1135 static int xenvif_set_skb_gso(struct xenvif *vif,
1136                               struct sk_buff *skb,
1137                               struct xen_netif_extra_info *gso)
1138 {
1139         if (!gso->u.gso.size) {
1140                 netdev_err(vif->dev, "GSO size must not be zero.\n");
1141                 xenvif_fatal_tx_err(vif);
1142                 return -EINVAL;
1143         }
1144
1145         switch (gso->u.gso.type) {
1146         case XEN_NETIF_GSO_TYPE_TCPV4:
1147                 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1148                 break;
1149         case XEN_NETIF_GSO_TYPE_TCPV6:
1150                 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1151                 break;
1152         default:
1153                 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1154                 xenvif_fatal_tx_err(vif);
1155                 return -EINVAL;
1156         }
1157
1158         skb_shinfo(skb)->gso_size = gso->u.gso.size;
1159         /* gso_segs will be calculated later */
1160
1161         return 0;
1162 }
1163
1164 static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
1165 {
1166         bool recalculate_partial_csum = false;
1167
1168         /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1169          * peers can fail to set NETRXF_csum_blank when sending a GSO
1170          * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1171          * recalculate the partial checksum.
1172          */
1173         if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1174                 queue->stats.rx_gso_checksum_fixup++;
1175                 skb->ip_summed = CHECKSUM_PARTIAL;
1176                 recalculate_partial_csum = true;
1177         }
1178
1179         /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1180         if (skb->ip_summed != CHECKSUM_PARTIAL)
1181                 return 0;
1182
1183         return skb_checksum_setup(skb, recalculate_partial_csum);
1184 }
1185
1186 static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
1187 {
1188         u64 now = get_jiffies_64();
1189         u64 next_credit = queue->credit_window_start +
1190                 msecs_to_jiffies(queue->credit_usec / 1000);
1191
1192         /* Timer could already be pending in rare cases. */
1193         if (timer_pending(&queue->credit_timeout)) {
1194                 queue->rate_limited = true;
1195                 return true;
1196         }
1197
1198         /* Passed the point where we can replenish credit? */
1199         if (time_after_eq64(now, next_credit)) {
1200                 queue->credit_window_start = now;
1201                 tx_add_credit(queue);
1202         }
1203
1204         /* Still too big to send right now? Set a callback. */
1205         if (size > queue->remaining_credit) {
1206                 queue->credit_timeout.data     =
1207                         (unsigned long)queue;
1208                 mod_timer(&queue->credit_timeout,
1209                           next_credit);
1210                 queue->credit_window_start = next_credit;
1211                 queue->rate_limited = true;
1212
1213                 return true;
1214         }
1215
1216         return false;
1217 }
1218
1219 /* No locking is required in xenvif_mcast_add/del() as they are
1220  * only ever invoked from NAPI poll. An RCU list is used because
1221  * xenvif_mcast_match() is called asynchronously, during start_xmit.
1222  */
1223
1224 static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
1225 {
1226         struct xenvif_mcast_addr *mcast;
1227
1228         if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
1229                 if (net_ratelimit())
1230                         netdev_err(vif->dev,
1231                                    "Too many multicast addresses\n");
1232                 return -ENOSPC;
1233         }
1234
1235         mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
1236         if (!mcast)
1237                 return -ENOMEM;
1238
1239         ether_addr_copy(mcast->addr, addr);
1240         list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
1241         vif->fe_mcast_count++;
1242
1243         return 0;
1244 }
1245
1246 static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
1247 {
1248         struct xenvif_mcast_addr *mcast;
1249
1250         list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
1251                 if (ether_addr_equal(addr, mcast->addr)) {
1252                         --vif->fe_mcast_count;
1253                         list_del_rcu(&mcast->entry);
1254                         kfree_rcu(mcast, rcu);
1255                         break;
1256                 }
1257         }
1258 }
1259
1260 bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
1261 {
1262         struct xenvif_mcast_addr *mcast;
1263
1264         rcu_read_lock();
1265         list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
1266                 if (ether_addr_equal(addr, mcast->addr)) {
1267                         rcu_read_unlock();
1268                         return true;
1269                 }
1270         }
1271         rcu_read_unlock();
1272
1273         return false;
1274 }
1275
1276 void xenvif_mcast_addr_list_free(struct xenvif *vif)
1277 {
1278         /* No need for locking or RCU here. NAPI poll and TX queue
1279          * are stopped.
1280          */
1281         while (!list_empty(&vif->fe_mcast_addr)) {
1282                 struct xenvif_mcast_addr *mcast;
1283
1284                 mcast = list_first_entry(&vif->fe_mcast_addr,
1285                                          struct xenvif_mcast_addr,
1286                                          entry);
1287                 --vif->fe_mcast_count;
1288                 list_del(&mcast->entry);
1289                 kfree(mcast);
1290         }
1291 }
1292
1293 static void xenvif_tx_build_gops(struct xenvif_queue *queue,
1294                                      int budget,
1295                                      unsigned *copy_ops,
1296                                      unsigned *map_ops)
1297 {
1298         struct gnttab_map_grant_ref *gop = queue->tx_map_ops;
1299         struct sk_buff *skb, *nskb;
1300         int ret;
1301         unsigned int frag_overflow;
1302
1303         while (skb_queue_len(&queue->tx_queue) < budget) {
1304                 struct xen_netif_tx_request txreq;
1305                 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
1306                 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1307                 u16 pending_idx;
1308                 RING_IDX idx;
1309                 int work_to_do;
1310                 unsigned int data_len;
1311                 pending_ring_idx_t index;
1312
1313                 if (queue->tx.sring->req_prod - queue->tx.req_cons >
1314                     XEN_NETIF_TX_RING_SIZE) {
1315                         netdev_err(queue->vif->dev,
1316                                    "Impossible number of requests. "
1317                                    "req_prod %d, req_cons %d, size %ld\n",
1318                                    queue->tx.sring->req_prod, queue->tx.req_cons,
1319                                    XEN_NETIF_TX_RING_SIZE);
1320                         xenvif_fatal_tx_err(queue->vif);
1321                         break;
1322                 }
1323
1324                 work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
1325                 if (!work_to_do)
1326                         break;
1327
1328                 idx = queue->tx.req_cons;
1329                 rmb(); /* Ensure that we see the request before we copy it. */
1330                 RING_COPY_REQUEST(&queue->tx, idx, &txreq);
1331
1332                 /* Credit-based scheduling. */
1333                 if (txreq.size > queue->remaining_credit &&
1334                     tx_credit_exceeded(queue, txreq.size))
1335                         break;
1336
1337                 queue->remaining_credit -= txreq.size;
1338
1339                 work_to_do--;
1340                 queue->tx.req_cons = ++idx;
1341
1342                 memset(extras, 0, sizeof(extras));
1343                 if (txreq.flags & XEN_NETTXF_extra_info) {
1344                         work_to_do = xenvif_get_extras(queue, extras,
1345                                                        work_to_do);
1346                         idx = queue->tx.req_cons;
1347                         if (unlikely(work_to_do < 0))
1348                                 break;
1349                 }
1350
1351                 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
1352                         struct xen_netif_extra_info *extra;
1353
1354                         extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
1355                         ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
1356
1357                         make_tx_response(queue, &txreq,
1358                                          (ret == 0) ?
1359                                          XEN_NETIF_RSP_OKAY :
1360                                          XEN_NETIF_RSP_ERROR);
1361                         push_tx_responses(queue);
1362                         continue;
1363                 }
1364
1365                 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
1366                         struct xen_netif_extra_info *extra;
1367
1368                         extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
1369                         xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
1370
1371                         make_tx_response(queue, &txreq, XEN_NETIF_RSP_OKAY);
1372                         push_tx_responses(queue);
1373                         continue;
1374                 }
1375
1376                 ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do);
1377                 if (unlikely(ret < 0))
1378                         break;
1379
1380                 idx += ret;
1381
1382                 if (unlikely(txreq.size < ETH_HLEN)) {
1383                         netdev_dbg(queue->vif->dev,
1384                                    "Bad packet size: %d\n", txreq.size);
1385                         xenvif_tx_err(queue, &txreq, idx);
1386                         break;
1387                 }
1388
1389                 /* No crossing a page as the payload mustn't fragment. */
1390                 if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
1391                         netdev_err(queue->vif->dev,
1392                                    "txreq.offset: %u, size: %u, end: %lu\n",
1393                                    txreq.offset, txreq.size,
1394                                    (unsigned long)(txreq.offset&~XEN_PAGE_MASK) + txreq.size);
1395                         xenvif_fatal_tx_err(queue->vif);
1396                         break;
1397                 }
1398
1399                 index = pending_index(queue->pending_cons);
1400                 pending_idx = queue->pending_ring[index];
1401
1402                 data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
1403                             ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
1404                         XEN_NETBACK_TX_COPY_LEN : txreq.size;
1405
1406                 skb = xenvif_alloc_skb(data_len);
1407                 if (unlikely(skb == NULL)) {
1408                         netdev_dbg(queue->vif->dev,
1409                                    "Can't allocate a skb in start_xmit.\n");
1410                         xenvif_tx_err(queue, &txreq, idx);
1411                         break;
1412                 }
1413
1414                 skb_shinfo(skb)->nr_frags = ret;
1415                 if (data_len < txreq.size)
1416                         skb_shinfo(skb)->nr_frags++;
1417                 /* At this point shinfo->nr_frags is in fact the number of
1418                  * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
1419                  */
1420                 frag_overflow = 0;
1421                 nskb = NULL;
1422                 if (skb_shinfo(skb)->nr_frags > MAX_SKB_FRAGS) {
1423                         frag_overflow = skb_shinfo(skb)->nr_frags - MAX_SKB_FRAGS;
1424                         BUG_ON(frag_overflow > MAX_SKB_FRAGS);
1425                         skb_shinfo(skb)->nr_frags = MAX_SKB_FRAGS;
1426                         nskb = xenvif_alloc_skb(0);
1427                         if (unlikely(nskb == NULL)) {
1428                                 skb_shinfo(skb)->nr_frags = 0;
1429                                 kfree_skb(skb);
1430                                 xenvif_tx_err(queue, &txreq, idx);
1431                                 if (net_ratelimit())
1432                                         netdev_err(queue->vif->dev,
1433                                                    "Can't allocate the frag_list skb.\n");
1434                                 break;
1435                         }
1436                 }
1437
1438                 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1439                         struct xen_netif_extra_info *gso;
1440                         gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1441
1442                         if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
1443                                 /* Failure in xenvif_set_skb_gso is fatal. */
1444                                 skb_shinfo(skb)->nr_frags = 0;
1445                                 kfree_skb(skb);
1446                                 kfree_skb(nskb);
1447                                 break;
1448                         }
1449                 }
1450
1451                 XENVIF_TX_CB(skb)->pending_idx = pending_idx;
1452
1453                 __skb_put(skb, data_len);
1454                 queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
1455                 queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
1456                 queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
1457
1458                 queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
1459                         virt_to_gfn(skb->data);
1460                 queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
1461                 queue->tx_copy_ops[*copy_ops].dest.offset =
1462                         offset_in_page(skb->data) & ~XEN_PAGE_MASK;
1463
1464                 queue->tx_copy_ops[*copy_ops].len = data_len;
1465                 queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
1466
1467                 (*copy_ops)++;
1468
1469                 if (data_len < txreq.size) {
1470                         frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1471                                              pending_idx);
1472                         xenvif_tx_create_map_op(queue, pending_idx, &txreq, gop);
1473                         gop++;
1474                 } else {
1475                         frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1476                                              INVALID_PENDING_IDX);
1477                         memcpy(&queue->pending_tx_info[pending_idx].req, &txreq,
1478                                sizeof(txreq));
1479                 }
1480
1481                 queue->pending_cons++;
1482
1483                 gop = xenvif_get_requests(queue, skb, txfrags, gop,
1484                                           frag_overflow, nskb);
1485
1486                 __skb_queue_tail(&queue->tx_queue, skb);
1487
1488                 queue->tx.req_cons = idx;
1489
1490                 if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
1491                     (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
1492                         break;
1493         }
1494
1495         (*map_ops) = gop - queue->tx_map_ops;
1496         return;
1497 }
1498
1499 /* Consolidate skb with a frag_list into a brand new one with local pages on
1500  * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1501  */
1502 static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1503 {
1504         unsigned int offset = skb_headlen(skb);
1505         skb_frag_t frags[MAX_SKB_FRAGS];
1506         int i, f;
1507         struct ubuf_info *uarg;
1508         struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1509
1510         queue->stats.tx_zerocopy_sent += 2;
1511         queue->stats.tx_frag_overflow++;
1512
1513         xenvif_fill_frags(queue, nskb);
1514         /* Subtract frags size, we will correct it later */
1515         skb->truesize -= skb->data_len;
1516         skb->len += nskb->len;
1517         skb->data_len += nskb->len;
1518
1519         /* create a brand new frags array and coalesce there */
1520         for (i = 0; offset < skb->len; i++) {
1521                 struct page *page;
1522                 unsigned int len;
1523
1524                 BUG_ON(i >= MAX_SKB_FRAGS);
1525                 page = alloc_page(GFP_ATOMIC);
1526                 if (!page) {
1527                         int j;
1528                         skb->truesize += skb->data_len;
1529                         for (j = 0; j < i; j++)
1530                                 put_page(frags[j].page.p);
1531                         return -ENOMEM;
1532                 }
1533
1534                 if (offset + PAGE_SIZE < skb->len)
1535                         len = PAGE_SIZE;
1536                 else
1537                         len = skb->len - offset;
1538                 if (skb_copy_bits(skb, offset, page_address(page), len))
1539                         BUG();
1540
1541                 offset += len;
1542                 frags[i].page.p = page;
1543                 frags[i].page_offset = 0;
1544                 skb_frag_size_set(&frags[i], len);
1545         }
1546
1547         /* Release all the original (foreign) frags. */
1548         for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
1549                 skb_frag_unref(skb, f);
1550         uarg = skb_shinfo(skb)->destructor_arg;
1551         /* increase inflight counter to offset decrement in callback */
1552         atomic_inc(&queue->inflight_packets);
1553         uarg->callback(uarg, true);
1554         skb_shinfo(skb)->destructor_arg = NULL;
1555
1556         /* Fill the skb with the new (local) frags. */
1557         memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
1558         skb_shinfo(skb)->nr_frags = i;
1559         skb->truesize += i * PAGE_SIZE;
1560
1561         return 0;
1562 }
1563
1564 static int xenvif_tx_submit(struct xenvif_queue *queue)
1565 {
1566         struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1567         struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1568         struct sk_buff *skb;
1569         int work_done = 0;
1570
1571         while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1572                 struct xen_netif_tx_request *txp;
1573                 u16 pending_idx;
1574                 unsigned data_len;
1575
1576                 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1577                 txp = &queue->pending_tx_info[pending_idx].req;
1578
1579                 /* Check the remap error code. */
1580                 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1581                         /* If there was an error, xenvif_tx_check_gop is
1582                          * expected to release all the frags which were mapped,
1583                          * so kfree_skb shouldn't do it again
1584                          */
1585                         skb_shinfo(skb)->nr_frags = 0;
1586                         if (skb_has_frag_list(skb)) {
1587                                 struct sk_buff *nskb =
1588                                                 skb_shinfo(skb)->frag_list;
1589                                 skb_shinfo(nskb)->nr_frags = 0;
1590                         }
1591                         kfree_skb(skb);
1592                         continue;
1593                 }
1594
1595                 data_len = skb->len;
1596                 callback_param(queue, pending_idx).ctx = NULL;
1597                 if (data_len < txp->size) {
1598                         /* Append the packet payload as a fragment. */
1599                         txp->offset += data_len;
1600                         txp->size -= data_len;
1601                 } else {
1602                         /* Schedule a response immediately. */
1603                         xenvif_idx_release(queue, pending_idx,
1604                                            XEN_NETIF_RSP_OKAY);
1605                 }
1606
1607                 if (txp->flags & XEN_NETTXF_csum_blank)
1608                         skb->ip_summed = CHECKSUM_PARTIAL;
1609                 else if (txp->flags & XEN_NETTXF_data_validated)
1610                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1611
1612                 xenvif_fill_frags(queue, skb);
1613
1614                 if (unlikely(skb_has_frag_list(skb))) {
1615                         struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1616                         xenvif_skb_zerocopy_prepare(queue, nskb);
1617                         if (xenvif_handle_frag_list(queue, skb)) {
1618                                 if (net_ratelimit())
1619                                         netdev_err(queue->vif->dev,
1620                                                    "Not enough memory to consolidate frag_list!\n");
1621                                 xenvif_skb_zerocopy_prepare(queue, skb);
1622                                 kfree_skb(skb);
1623                                 continue;
1624                         }
1625                         /* Copied all the bits from the frag list -- free it. */
1626                         skb_frag_list_init(skb);
1627                         kfree_skb(nskb);
1628                 }
1629
1630                 skb->dev      = queue->vif->dev;
1631                 skb->protocol = eth_type_trans(skb, skb->dev);
1632                 skb_reset_network_header(skb);
1633
1634                 if (checksum_setup(queue, skb)) {
1635                         netdev_dbg(queue->vif->dev,
1636                                    "Can't setup checksum in net_tx_action\n");
1637                         /* We have to set this flag to trigger the callback */
1638                         if (skb_shinfo(skb)->destructor_arg)
1639                                 xenvif_skb_zerocopy_prepare(queue, skb);
1640                         kfree_skb(skb);
1641                         continue;
1642                 }
1643
1644                 skb_probe_transport_header(skb, 0);
1645
1646                 /* If the packet is GSO then we will have just set up the
1647                  * transport header offset in checksum_setup so it's now
1648                  * straightforward to calculate gso_segs.
1649                  */
1650                 if (skb_is_gso(skb)) {
1651                         int mss = skb_shinfo(skb)->gso_size;
1652                         int hdrlen = skb_transport_header(skb) -
1653                                 skb_mac_header(skb) +
1654                                 tcp_hdrlen(skb);
1655
1656                         skb_shinfo(skb)->gso_segs =
1657                                 DIV_ROUND_UP(skb->len - hdrlen, mss);
1658                 }
1659
1660                 queue->stats.rx_bytes += skb->len;
1661                 queue->stats.rx_packets++;
1662
1663                 work_done++;
1664
1665                 /* Set this flag right before netif_receive_skb, otherwise
1666                  * someone might think this packet already left netback, and
1667                  * do a skb_copy_ubufs while we are still in control of the
1668                  * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1669                  */
1670                 if (skb_shinfo(skb)->destructor_arg) {
1671                         xenvif_skb_zerocopy_prepare(queue, skb);
1672                         queue->stats.tx_zerocopy_sent++;
1673                 }
1674
1675                 netif_receive_skb(skb);
1676         }
1677
1678         return work_done;
1679 }
1680
1681 void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
1682 {
1683         unsigned long flags;
1684         pending_ring_idx_t index;
1685         struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1686
1687         /* This is the only place where we grab this lock, to protect callbacks
1688          * from each other.
1689          */
1690         spin_lock_irqsave(&queue->callback_lock, flags);
1691         do {
1692                 u16 pending_idx = ubuf->desc;
1693                 ubuf = (struct ubuf_info *) ubuf->ctx;
1694                 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1695                         MAX_PENDING_REQS);
1696                 index = pending_index(queue->dealloc_prod);
1697                 queue->dealloc_ring[index] = pending_idx;
1698                 /* Sync with xenvif_tx_dealloc_action:
1699                  * insert idx then incr producer.
1700                  */
1701                 smp_wmb();
1702                 queue->dealloc_prod++;
1703         } while (ubuf);
1704         spin_unlock_irqrestore(&queue->callback_lock, flags);
1705
1706         if (likely(zerocopy_success))
1707                 queue->stats.tx_zerocopy_success++;
1708         else
1709                 queue->stats.tx_zerocopy_fail++;
1710         xenvif_skb_zerocopy_complete(queue);
1711 }
1712
1713 static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1714 {
1715         struct gnttab_unmap_grant_ref *gop;
1716         pending_ring_idx_t dc, dp;
1717         u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1718         unsigned int i = 0;
1719
1720         dc = queue->dealloc_cons;
1721         gop = queue->tx_unmap_ops;
1722
1723         /* Free up any grants we have finished using */
1724         do {
1725                 dp = queue->dealloc_prod;
1726
1727                 /* Ensure we see all indices enqueued by all
1728                  * xenvif_zerocopy_callback().
1729                  */
1730                 smp_rmb();
1731
1732                 while (dc != dp) {
1733                         BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS);
1734                         pending_idx =
1735                                 queue->dealloc_ring[pending_index(dc++)];
1736
1737                         pending_idx_release[gop - queue->tx_unmap_ops] =
1738                                 pending_idx;
1739                         queue->pages_to_unmap[gop - queue->tx_unmap_ops] =
1740                                 queue->mmap_pages[pending_idx];
1741                         gnttab_set_unmap_op(gop,
1742                                             idx_to_kaddr(queue, pending_idx),
1743                                             GNTMAP_host_map,
1744                                             queue->grant_tx_handle[pending_idx]);
1745                         xenvif_grant_handle_reset(queue, pending_idx);
1746                         ++gop;
1747                 }
1748
1749         } while (dp != queue->dealloc_prod);
1750
1751         queue->dealloc_cons = dc;
1752
1753         if (gop - queue->tx_unmap_ops > 0) {
1754                 int ret;
1755                 ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1756                                         NULL,
1757                                         queue->pages_to_unmap,
1758                                         gop - queue->tx_unmap_ops);
1759                 if (ret) {
1760                         netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tu ret %d\n",
1761                                    gop - queue->tx_unmap_ops, ret);
1762                         for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1763                                 if (gop[i].status != GNTST_okay)
1764                                         netdev_err(queue->vif->dev,
1765                                                    " host_addr: 0x%llx handle: 0x%x status: %d\n",
1766                                                    gop[i].host_addr,
1767                                                    gop[i].handle,
1768                                                    gop[i].status);
1769                         }
1770                         BUG();
1771                 }
1772         }
1773
1774         for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1775                 xenvif_idx_release(queue, pending_idx_release[i],
1776                                    XEN_NETIF_RSP_OKAY);
1777 }
1778
1779
1780 /* Called after netfront has transmitted */
1781 int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1782 {
1783         unsigned nr_mops, nr_cops = 0;
1784         int work_done, ret;
1785
1786         if (unlikely(!tx_work_todo(queue)))
1787                 return 0;
1788
1789         xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1790
1791         if (nr_cops == 0)
1792                 return 0;
1793
1794         gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1795         if (nr_mops != 0) {
1796                 ret = gnttab_map_refs(queue->tx_map_ops,
1797                                       NULL,
1798                                       queue->pages_to_map,
1799                                       nr_mops);
1800                 if (ret) {
1801                         unsigned int i;
1802
1803                         netdev_err(queue->vif->dev, "Map fail: nr %u ret %d\n",
1804                                    nr_mops, ret);
1805                         for (i = 0; i < nr_mops; ++i)
1806                                 WARN_ON_ONCE(queue->tx_map_ops[i].status ==
1807                                              GNTST_okay);
1808                 }
1809         }
1810
1811         work_done = xenvif_tx_submit(queue);
1812
1813         return work_done;
1814 }
1815
1816 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1817                                u8 status)
1818 {
1819         struct pending_tx_info *pending_tx_info;
1820         pending_ring_idx_t index;
1821         unsigned long flags;
1822
1823         pending_tx_info = &queue->pending_tx_info[pending_idx];
1824
1825         spin_lock_irqsave(&queue->response_lock, flags);
1826
1827         make_tx_response(queue, &pending_tx_info->req, status);
1828
1829         /* Release the pending index before pusing the Tx response so
1830          * its available before a new Tx request is pushed by the
1831          * frontend.
1832          */
1833         index = pending_index(queue->pending_prod++);
1834         queue->pending_ring[index] = pending_idx;
1835
1836         push_tx_responses(queue);
1837
1838         spin_unlock_irqrestore(&queue->response_lock, flags);
1839 }
1840
1841
1842 static void make_tx_response(struct xenvif_queue *queue,
1843                              struct xen_netif_tx_request *txp,
1844                              s8       st)
1845 {
1846         RING_IDX i = queue->tx.rsp_prod_pvt;
1847         struct xen_netif_tx_response *resp;
1848
1849         resp = RING_GET_RESPONSE(&queue->tx, i);
1850         resp->id     = txp->id;
1851         resp->status = st;
1852
1853         if (txp->flags & XEN_NETTXF_extra_info)
1854                 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1855
1856         queue->tx.rsp_prod_pvt = ++i;
1857 }
1858
1859 static void push_tx_responses(struct xenvif_queue *queue)
1860 {
1861         int notify;
1862
1863         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1864         if (notify)
1865                 notify_remote_via_irq(queue->tx_irq);
1866 }
1867
1868 static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
1869                                              u16      id,
1870                                              s8       st,
1871                                              u16      offset,
1872                                              u16      size,
1873                                              u16      flags)
1874 {
1875         RING_IDX i = queue->rx.rsp_prod_pvt;
1876         struct xen_netif_rx_response *resp;
1877
1878         resp = RING_GET_RESPONSE(&queue->rx, i);
1879         resp->offset     = offset;
1880         resp->flags      = flags;
1881         resp->id         = id;
1882         resp->status     = (s16)size;
1883         if (st < 0)
1884                 resp->status = (s16)st;
1885
1886         queue->rx.rsp_prod_pvt = ++i;
1887
1888         return resp;
1889 }
1890
1891 void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1892 {
1893         int ret;
1894         struct gnttab_unmap_grant_ref tx_unmap_op;
1895
1896         gnttab_set_unmap_op(&tx_unmap_op,
1897                             idx_to_kaddr(queue, pending_idx),
1898                             GNTMAP_host_map,
1899                             queue->grant_tx_handle[pending_idx]);
1900         xenvif_grant_handle_reset(queue, pending_idx);
1901
1902         ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1903                                 &queue->mmap_pages[pending_idx], 1);
1904         if (ret) {
1905                 netdev_err(queue->vif->dev,
1906                            "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: 0x%x status: %d\n",
1907                            ret,
1908                            pending_idx,
1909                            tx_unmap_op.host_addr,
1910                            tx_unmap_op.handle,
1911                            tx_unmap_op.status);
1912                 BUG();
1913         }
1914 }
1915
1916 static inline int tx_work_todo(struct xenvif_queue *queue)
1917 {
1918         if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1919                 return 1;
1920
1921         return 0;
1922 }
1923
1924 static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1925 {
1926         return queue->dealloc_cons != queue->dealloc_prod;
1927 }
1928
1929 void xenvif_unmap_frontend_rings(struct xenvif_queue *queue)
1930 {
1931         if (queue->tx.sring)
1932                 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1933                                         queue->tx.sring);
1934         if (queue->rx.sring)
1935                 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1936                                         queue->rx.sring);
1937 }
1938
1939 int xenvif_map_frontend_rings(struct xenvif_queue *queue,
1940                               grant_ref_t tx_ring_ref,
1941                               grant_ref_t rx_ring_ref)
1942 {
1943         void *addr;
1944         struct xen_netif_tx_sring *txs;
1945         struct xen_netif_rx_sring *rxs;
1946
1947         int err = -ENOMEM;
1948
1949         err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1950                                      &tx_ring_ref, 1, &addr);
1951         if (err)
1952                 goto err;
1953
1954         txs = (struct xen_netif_tx_sring *)addr;
1955         BACK_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
1956
1957         err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1958                                      &rx_ring_ref, 1, &addr);
1959         if (err)
1960                 goto err;
1961
1962         rxs = (struct xen_netif_rx_sring *)addr;
1963         BACK_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
1964
1965         return 0;
1966
1967 err:
1968         xenvif_unmap_frontend_rings(queue);
1969         return err;
1970 }
1971
1972 static void xenvif_queue_carrier_off(struct xenvif_queue *queue)
1973 {
1974         struct xenvif *vif = queue->vif;
1975
1976         queue->stalled = true;
1977
1978         /* At least one queue has stalled? Disable the carrier. */
1979         spin_lock(&vif->lock);
1980         if (vif->stalled_queues++ == 0) {
1981                 netdev_info(vif->dev, "Guest Rx stalled");
1982                 netif_carrier_off(vif->dev);
1983         }
1984         spin_unlock(&vif->lock);
1985 }
1986
1987 static void xenvif_queue_carrier_on(struct xenvif_queue *queue)
1988 {
1989         struct xenvif *vif = queue->vif;
1990
1991         queue->last_rx_time = jiffies; /* Reset Rx stall detection. */
1992         queue->stalled = false;
1993
1994         /* All queues are ready? Enable the carrier. */
1995         spin_lock(&vif->lock);
1996         if (--vif->stalled_queues == 0) {
1997                 netdev_info(vif->dev, "Guest Rx ready");
1998                 netif_carrier_on(vif->dev);
1999         }
2000         spin_unlock(&vif->lock);
2001 }
2002
2003 static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue)
2004 {
2005         RING_IDX prod, cons;
2006
2007         prod = queue->rx.sring->req_prod;
2008         cons = queue->rx.req_cons;
2009
2010         return !queue->stalled && prod - cons < 1
2011                 && time_after(jiffies,
2012                               queue->last_rx_time + queue->vif->stall_timeout);
2013 }
2014
2015 static bool xenvif_rx_queue_ready(struct xenvif_queue *queue)
2016 {
2017         RING_IDX prod, cons;
2018
2019         prod = queue->rx.sring->req_prod;
2020         cons = queue->rx.req_cons;
2021
2022         return queue->stalled && prod - cons >= 1;
2023 }
2024
2025 bool xenvif_have_rx_work(struct xenvif_queue *queue, bool test_kthread)
2026 {
2027         return (!skb_queue_empty(&queue->rx_queue)
2028                 && xenvif_rx_ring_slots_available(queue))
2029                 || (queue->vif->stall_timeout &&
2030                     (xenvif_rx_queue_stalled(queue)
2031                      || xenvif_rx_queue_ready(queue)))
2032                 || (test_kthread && kthread_should_stop())
2033                 || queue->vif->disabled;
2034 }
2035
2036 static long xenvif_rx_queue_timeout(struct xenvif_queue *queue)
2037 {
2038         struct sk_buff *skb;
2039         long timeout;
2040
2041         skb = skb_peek(&queue->rx_queue);
2042         if (!skb)
2043                 return MAX_SCHEDULE_TIMEOUT;
2044
2045         timeout = XENVIF_RX_CB(skb)->expires - jiffies;
2046         return timeout < 0 ? 0 : timeout;
2047 }
2048
2049 /* Wait until the guest Rx thread has work.
2050  *
2051  * The timeout needs to be adjusted based on the current head of the
2052  * queue (and not just the head at the beginning).  In particular, if
2053  * the queue is initially empty an infinite timeout is used and this
2054  * needs to be reduced when a skb is queued.
2055  *
2056  * This cannot be done with wait_event_timeout() because it only
2057  * calculates the timeout once.
2058  */
2059 static void xenvif_wait_for_rx_work(struct xenvif_queue *queue)
2060 {
2061         DEFINE_WAIT(wait);
2062
2063         if (xenvif_have_rx_work(queue, true))
2064                 return;
2065
2066         for (;;) {
2067                 long ret;
2068
2069                 prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE);
2070                 if (xenvif_have_rx_work(queue, true))
2071                         break;
2072                 if (xenvif_atomic_fetch_andnot(NETBK_RX_EOI | NETBK_COMMON_EOI,
2073                                         &queue->eoi_pending) &
2074                     (NETBK_RX_EOI | NETBK_COMMON_EOI))
2075                         xen_irq_lateeoi(queue->rx_irq, 0);
2076
2077                 ret = schedule_timeout(xenvif_rx_queue_timeout(queue));
2078                 if (!ret)
2079                         break;
2080         }
2081         finish_wait(&queue->wq, &wait);
2082 }
2083
2084 int xenvif_kthread_guest_rx(void *data)
2085 {
2086         struct xenvif_queue *queue = data;
2087         struct xenvif *vif = queue->vif;
2088
2089         if (!vif->stall_timeout)
2090                 xenvif_queue_carrier_on(queue);
2091
2092         for (;;) {
2093                 xenvif_wait_for_rx_work(queue);
2094
2095                 if (kthread_should_stop())
2096                         break;
2097
2098                 /* This frontend is found to be rogue, disable it in
2099                  * kthread context. Currently this is only set when
2100                  * netback finds out frontend sends malformed packet,
2101                  * but we cannot disable the interface in softirq
2102                  * context so we defer it here, if this thread is
2103                  * associated with queue 0.
2104                  */
2105                 if (unlikely(vif->disabled && queue->id == 0)) {
2106                         xenvif_carrier_off(vif);
2107                         break;
2108                 }
2109
2110                 if (!skb_queue_empty(&queue->rx_queue))
2111                         xenvif_rx_action(queue);
2112
2113                 /* If the guest hasn't provided any Rx slots for a
2114                  * while it's probably not responsive, drop the
2115                  * carrier so packets are dropped earlier.
2116                  */
2117                 if (vif->stall_timeout) {
2118                         if (xenvif_rx_queue_stalled(queue))
2119                                 xenvif_queue_carrier_off(queue);
2120                         else if (xenvif_rx_queue_ready(queue))
2121                                 xenvif_queue_carrier_on(queue);
2122                 }
2123
2124                 /* Queued packets may have foreign pages from other
2125                  * domains.  These cannot be queued indefinitely as
2126                  * this would starve guests of grant refs and transmit
2127                  * slots.
2128                  */
2129                 xenvif_rx_queue_drop_expired(queue);
2130
2131                 xenvif_rx_queue_maybe_wake(queue);
2132
2133                 cond_resched();
2134         }
2135
2136         /* Bin any remaining skbs */
2137         xenvif_rx_queue_purge(queue);
2138
2139         return 0;
2140 }
2141
2142 static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
2143 {
2144         /* Dealloc thread must remain running until all inflight
2145          * packets complete.
2146          */
2147         return kthread_should_stop() &&
2148                 !atomic_read(&queue->inflight_packets);
2149 }
2150
2151 int xenvif_dealloc_kthread(void *data)
2152 {
2153         struct xenvif_queue *queue = data;
2154
2155         for (;;) {
2156                 wait_event_interruptible(queue->dealloc_wq,
2157                                          tx_dealloc_work_todo(queue) ||
2158                                          xenvif_dealloc_kthread_should_stop(queue));
2159                 if (xenvif_dealloc_kthread_should_stop(queue))
2160                         break;
2161
2162                 xenvif_tx_dealloc_action(queue);
2163                 cond_resched();
2164         }
2165
2166         /* Unmap anything remaining*/
2167         if (tx_dealloc_work_todo(queue))
2168                 xenvif_tx_dealloc_action(queue);
2169
2170         return 0;
2171 }
2172
2173 static int __init netback_init(void)
2174 {
2175         int rc = 0;
2176
2177         if (!xen_domain())
2178                 return -ENODEV;
2179
2180         /* Allow as many queues as there are CPUs but max. 8 if user has not
2181          * specified a value.
2182          */
2183         if (xenvif_max_queues == 0)
2184                 xenvif_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
2185                                           num_online_cpus());
2186
2187         if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
2188                 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
2189                         fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
2190                 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
2191         }
2192
2193         rc = xenvif_xenbus_init();
2194         if (rc)
2195                 goto failed_init;
2196
2197 #ifdef CONFIG_DEBUG_FS
2198         xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
2199         if (IS_ERR_OR_NULL(xen_netback_dbg_root))
2200                 pr_warn("Init of debugfs returned %ld!\n",
2201                         PTR_ERR(xen_netback_dbg_root));
2202 #endif /* CONFIG_DEBUG_FS */
2203
2204         return 0;
2205
2206 failed_init:
2207         return rc;
2208 }
2209
2210 module_init(netback_init);
2211
2212 static void __exit netback_fini(void)
2213 {
2214 #ifdef CONFIG_DEBUG_FS
2215         if (!IS_ERR_OR_NULL(xen_netback_dbg_root))
2216                 debugfs_remove_recursive(xen_netback_dbg_root);
2217 #endif /* CONFIG_DEBUG_FS */
2218         xenvif_xenbus_fini();
2219 }
2220 module_exit(netback_fini);
2221
2222 MODULE_LICENSE("Dual BSD/GPL");
2223 MODULE_ALIAS("xen-backend:vif");