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