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 /* This is the maximum number of flows in the hash cache. */
  94 #define XENVIF_HASH_CACHE_SIZE_DEFAULT 64
  95 unsigned int xenvif_hash_cache_size = XENVIF_HASH_CACHE_SIZE_DEFAULT;
  96 module_param_named(hash_cache_size, xenvif_hash_cache_size, uint, 0644);
  97 MODULE_PARM_DESC(hash_cache_size, "Number of flows in the hash cache");
  98
  99 /* The module parameter tells that we have to put data
 100  * for xen-netfront with the XDP_PACKET_HEADROOM offset
 101  * needed for XDP processing
 102  */
 103 bool provides_xdp_headroom = true;
 104 module_param(provides_xdp_headroom, bool, 0644);
 105
 106 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
 107                                u8 status);
 108
 109 static void make_tx_response(struct xenvif_queue *queue,
 110                              struct xen_netif_tx_request *txp,
 111                              unsigned int extra_count,
 112                              s8       st);
 113 static void push_tx_responses(struct xenvif_queue *queue);
 114
 115 static inline int tx_work_todo(struct xenvif_queue *queue);
 116
 117 static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
 118                                        u16 idx)
 119 {
 120         return page_to_pfn(queue->mmap_pages[idx]);
 121 }
 122
 123 static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
 124                                          u16 idx)
 125 {
 126         return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
 127 }
 128
 129 #define callback_param(vif, pending_idx) \
 130         (vif->pending_tx_info[pending_idx].callback_struct)
 131
 132 /* Find the containing VIF's structure from a pointer in pending_tx_info array
 133  */
 134 static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
 135 {
 136         u16 pending_idx = ubuf->desc;
 137         struct pending_tx_info *temp =
 138                 container_of(ubuf, struct pending_tx_info, callback_struct);
 139         return container_of(temp - pending_idx,
 140                             struct xenvif_queue,
 141                             pending_tx_info[0]);
 142 }
 143
 144 static u16 frag_get_pending_idx(skb_frag_t *frag)
 145 {
 146         return (u16)skb_frag_off(frag);
 147 }
 148
 149 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
 150 {
 151         skb_frag_off_set(frag, pending_idx);
 152 }
 153
 154 static inline pending_ring_idx_t pending_index(unsigned i)
 155 {
 156         return i & (MAX_PENDING_REQS-1);
 157 }
 158
 159 void xenvif_kick_thread(struct xenvif_queue *queue)
 160 {
 161         wake_up(&queue->wq);
 162 }
 163
 164 void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
 165 {
 166         int more_to_do;
 167
 168         RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
 169
 170         if (more_to_do)
 171                 napi_schedule(&queue->napi);
 172 }
 173
 174 static void tx_add_credit(struct xenvif_queue *queue)
 175 {
 176         unsigned long max_burst, max_credit;
 177
 178         /*
 179          * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
 180          * Otherwise the interface can seize up due to insufficient credit.
 181          */
 182         max_burst = max(131072UL, queue->credit_bytes);
 183
 184         /* Take care that adding a new chunk of credit doesn't wrap to zero. */
 185         max_credit = queue->remaining_credit + queue->credit_bytes;
 186         if (max_credit < queue->remaining_credit)
 187                 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
 188
 189         queue->remaining_credit = min(max_credit, max_burst);
 190         queue->rate_limited = false;
 191 }
 192
 193 void xenvif_tx_credit_callback(struct timer_list *t)
 194 {
 195         struct xenvif_queue *queue = from_timer(queue, t, credit_timeout);
 196         tx_add_credit(queue);
 197         xenvif_napi_schedule_or_enable_events(queue);
 198 }
 199
 200 static void xenvif_tx_err(struct xenvif_queue *queue,
 201                           struct xen_netif_tx_request *txp,
 202                           unsigned int extra_count, RING_IDX end)
 203 {
 204         RING_IDX cons = queue->tx.req_cons;
 205         unsigned long flags;
 206
 207         do {
 208                 spin_lock_irqsave(&queue->response_lock, flags);
 209                 make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR);
 210                 push_tx_responses(queue);
 211                 spin_unlock_irqrestore(&queue->response_lock, flags);
 212                 if (cons == end)
 213                         break;
 214                 RING_COPY_REQUEST(&queue->tx, cons++, txp);
 215                 extra_count = 0; /* only the first frag can have extras */
 216         } while (1);
 217         queue->tx.req_cons = cons;
 218 }
 219
 220 static void xenvif_fatal_tx_err(struct xenvif *vif)
 221 {
 222         netdev_err(vif->dev, "fatal error; disabling device\n");
 223         vif->disabled = true;
 224         /* Disable the vif from queue 0's kthread */
 225         if (vif->num_queues)
 226                 xenvif_kick_thread(&vif->queues[0]);
 227 }
 228
 229 static int xenvif_count_requests(struct xenvif_queue *queue,
 230                                  struct xen_netif_tx_request *first,
 231                                  unsigned int extra_count,
 232                                  struct xen_netif_tx_request *txp,
 233                                  int work_to_do)
 234 {
 235         RING_IDX cons = queue->tx.req_cons;
 236         int slots = 0;
 237         int drop_err = 0;
 238         int more_data;
 239
 240         if (!(first->flags & XEN_NETTXF_more_data))
 241                 return 0;
 242
 243         do {
 244                 struct xen_netif_tx_request dropped_tx = { 0 };
 245
 246                 if (slots >= work_to_do) {
 247                         netdev_err(queue->vif->dev,
 248                                    "Asked for %d slots but exceeds this limit\n",
 249                                    work_to_do);
 250                         xenvif_fatal_tx_err(queue->vif);
 251                         return -ENODATA;
 252                 }
 253
 254                 /* This guest is really using too many slots and
 255                  * considered malicious.
 256                  */
 257                 if (unlikely(slots >= fatal_skb_slots)) {
 258                         netdev_err(queue->vif->dev,
 259                                    "Malicious frontend using %d slots, threshold %u\n",
 260                                    slots, fatal_skb_slots);
 261                         xenvif_fatal_tx_err(queue->vif);
 262                         return -E2BIG;
 263                 }
 264
 265                 /* Xen network protocol had implicit dependency on
 266                  * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
 267                  * the historical MAX_SKB_FRAGS value 18 to honor the
 268                  * same behavior as before. Any packet using more than
 269                  * 18 slots but less than fatal_skb_slots slots is
 270                  * dropped
 271                  */
 272                 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
 273                         if (net_ratelimit())
 274                                 netdev_dbg(queue->vif->dev,
 275                                            "Too many slots (%d) exceeding limit (%d), dropping packet\n",
 276                                            slots, XEN_NETBK_LEGACY_SLOTS_MAX);
 277                         drop_err = -E2BIG;
 278                 }
 279
 280                 if (drop_err)
 281                         txp = &dropped_tx;
 282
 283                 RING_COPY_REQUEST(&queue->tx, cons + slots, txp);
 284
 285                 /* If the guest submitted a frame >= 64 KiB then
 286                  * first->size overflowed and following slots will
 287                  * appear to be larger than the frame.
 288                  *
 289                  * This cannot be fatal error as there are buggy
 290                  * frontends that do this.
 291                  *
 292                  * Consume all slots and drop the packet.
 293                  */
 294                 if (!drop_err && txp->size > first->size) {
 295                         if (net_ratelimit())
 296                                 netdev_dbg(queue->vif->dev,
 297                                            "Invalid tx request, slot size %u > remaining size %u\n",
 298                                            txp->size, first->size);
 299                         drop_err = -EIO;
 300                 }
 301
 302                 first->size -= txp->size;
 303                 slots++;
 304
 305                 if (unlikely((txp->offset + txp->size) > XEN_PAGE_SIZE)) {
 306                         netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n",
 307                                  txp->offset, txp->size);
 308                         xenvif_fatal_tx_err(queue->vif);
 309                         return -EINVAL;
 310                 }
 311
 312                 more_data = txp->flags & XEN_NETTXF_more_data;
 313
 314                 if (!drop_err)
 315                         txp++;
 316
 317         } while (more_data);
 318
 319         if (drop_err) {
 320                 xenvif_tx_err(queue, first, extra_count, cons + slots);
 321                 return drop_err;
 322         }
 323
 324         return slots;
 325 }
 326
 327
 328 struct xenvif_tx_cb {
 329         u16 pending_idx;
 330 };
 331
 332 #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
 333
 334 static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
 335                                            u16 pending_idx,
 336                                            struct xen_netif_tx_request *txp,
 337                                            unsigned int extra_count,
 338                                            struct gnttab_map_grant_ref *mop)
 339 {
 340         queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
 341         gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
 342                           GNTMAP_host_map | GNTMAP_readonly,
 343                           txp->gref, queue->vif->domid);
 344
 345         memcpy(&queue->pending_tx_info[pending_idx].req, txp,
 346                sizeof(*txp));
 347         queue->pending_tx_info[pending_idx].extra_count = extra_count;
 348 }
 349
 350 static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
 351 {
 352         struct sk_buff *skb =
 353                 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
 354                           GFP_ATOMIC | __GFP_NOWARN);
 355         if (unlikely(skb == NULL))
 356                 return NULL;
 357
 358         /* Packets passed to netif_rx() must have some headroom. */
 359         skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
 360
 361         /* Initialize it here to avoid later surprises */
 362         skb_shinfo(skb)->destructor_arg = NULL;
 363
 364         return skb;
 365 }
 366
 367 static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
 368                                                         struct sk_buff *skb,
 369                                                         struct xen_netif_tx_request *txp,
 370                                                         struct gnttab_map_grant_ref *gop,
 371                                                         unsigned int frag_overflow,
 372                                                         struct sk_buff *nskb)
 373 {
 374         struct skb_shared_info *shinfo = skb_shinfo(skb);
 375         skb_frag_t *frags = shinfo->frags;
 376         u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
 377         int start;
 378         pending_ring_idx_t index;
 379         unsigned int nr_slots;
 380
 381         nr_slots = shinfo->nr_frags;
 382
 383         /* Skip first skb fragment if it is on same page as header fragment. */
 384         start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
 385
 386         for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
 387              shinfo->nr_frags++, txp++, gop++) {
 388                 index = pending_index(queue->pending_cons++);
 389                 pending_idx = queue->pending_ring[index];
 390                 xenvif_tx_create_map_op(queue, pending_idx, txp, 0, gop);
 391                 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
 392         }
 393
 394         if (frag_overflow) {
 395
 396                 shinfo = skb_shinfo(nskb);
 397                 frags = shinfo->frags;
 398
 399                 for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
 400                      shinfo->nr_frags++, txp++, gop++) {
 401                         index = pending_index(queue->pending_cons++);
 402                         pending_idx = queue->pending_ring[index];
 403                         xenvif_tx_create_map_op(queue, pending_idx, txp, 0,
 404                                                 gop);
 405                         frag_set_pending_idx(&frags[shinfo->nr_frags],
 406                                              pending_idx);
 407                 }
 408
 409                 skb_shinfo(skb)->frag_list = nskb;
 410         }
 411
 412         return gop;
 413 }
 414
 415 static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
 416                                            u16 pending_idx,
 417                                            grant_handle_t handle)
 418 {
 419         if (unlikely(queue->grant_tx_handle[pending_idx] !=
 420                      NETBACK_INVALID_HANDLE)) {
 421                 netdev_err(queue->vif->dev,
 422                            "Trying to overwrite active handle! pending_idx: 0x%x\n",
 423                            pending_idx);
 424                 BUG();
 425         }
 426         queue->grant_tx_handle[pending_idx] = handle;
 427 }
 428
 429 static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
 430                                              u16 pending_idx)
 431 {
 432         if (unlikely(queue->grant_tx_handle[pending_idx] ==
 433                      NETBACK_INVALID_HANDLE)) {
 434                 netdev_err(queue->vif->dev,
 435                            "Trying to unmap invalid handle! pending_idx: 0x%x\n",
 436                            pending_idx);
 437                 BUG();
 438         }
 439         queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
 440 }
 441
 442 static int xenvif_tx_check_gop(struct xenvif_queue *queue,
 443                                struct sk_buff *skb,
 444                                struct gnttab_map_grant_ref **gopp_map,
 445                                struct gnttab_copy **gopp_copy)
 446 {
 447         struct gnttab_map_grant_ref *gop_map = *gopp_map;
 448         u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
 449         /* This always points to the shinfo of the skb being checked, which
 450          * could be either the first or the one on the frag_list
 451          */
 452         struct skb_shared_info *shinfo = skb_shinfo(skb);
 453         /* If this is non-NULL, we are currently checking the frag_list skb, and
 454          * this points to the shinfo of the first one
 455          */
 456         struct skb_shared_info *first_shinfo = NULL;
 457         int nr_frags = shinfo->nr_frags;
 458         const bool sharedslot = nr_frags &&
 459                                 frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
 460         int i, err;
 461
 462         /* Check status of header. */
 463         err = (*gopp_copy)->status;
 464         if (unlikely(err)) {
 465                 if (net_ratelimit())
 466                         netdev_dbg(queue->vif->dev,
 467                                    "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
 468                                    (*gopp_copy)->status,
 469                                    pending_idx,
 470                                    (*gopp_copy)->source.u.ref);
 471                 /* The first frag might still have this slot mapped */
 472                 if (!sharedslot)
 473                         xenvif_idx_release(queue, pending_idx,
 474                                            XEN_NETIF_RSP_ERROR);
 475         }
 476         (*gopp_copy)++;
 477
 478 check_frags:
 479         for (i = 0; i < nr_frags; i++, gop_map++) {
 480                 int j, newerr;
 481
 482                 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
 483
 484                 /* Check error status: if okay then remember grant handle. */
 485                 newerr = gop_map->status;
 486
 487                 if (likely(!newerr)) {
 488                         xenvif_grant_handle_set(queue,
 489                                                 pending_idx,
 490                                                 gop_map->handle);
 491                         /* Had a previous error? Invalidate this fragment. */
 492                         if (unlikely(err)) {
 493                                 xenvif_idx_unmap(queue, pending_idx);
 494                                 /* If the mapping of the first frag was OK, but
 495                                  * the header's copy failed, and they are
 496                                  * sharing a slot, send an error
 497                                  */
 498                                 if (i == 0 && sharedslot)
 499                                         xenvif_idx_release(queue, pending_idx,
 500                                                            XEN_NETIF_RSP_ERROR);
 501                                 else
 502                                         xenvif_idx_release(queue, pending_idx,
 503                                                            XEN_NETIF_RSP_OKAY);
 504                         }
 505                         continue;
 506                 }
 507
 508                 /* Error on this fragment: respond to client with an error. */
 509                 if (net_ratelimit())
 510                         netdev_dbg(queue->vif->dev,
 511                                    "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
 512                                    i,
 513                                    gop_map->status,
 514                                    pending_idx,
 515                                    gop_map->ref);
 516
 517                 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
 518
 519                 /* Not the first error? Preceding frags already invalidated. */
 520                 if (err)
 521                         continue;
 522
 523                 /* First error: if the header haven't shared a slot with the
 524                  * first frag, release it as well.
 525                  */
 526                 if (!sharedslot)
 527                         xenvif_idx_release(queue,
 528                                            XENVIF_TX_CB(skb)->pending_idx,
 529                                            XEN_NETIF_RSP_OKAY);
 530
 531                 /* Invalidate preceding fragments of this skb. */
 532                 for (j = 0; j < i; j++) {
 533                         pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
 534                         xenvif_idx_unmap(queue, pending_idx);
 535                         xenvif_idx_release(queue, pending_idx,
 536                                            XEN_NETIF_RSP_OKAY);
 537                 }
 538
 539                 /* And if we found the error while checking the frag_list, unmap
 540                  * the first skb's frags
 541                  */
 542                 if (first_shinfo) {
 543                         for (j = 0; j < first_shinfo->nr_frags; j++) {
 544                                 pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
 545                                 xenvif_idx_unmap(queue, pending_idx);
 546                                 xenvif_idx_release(queue, pending_idx,
 547                                                    XEN_NETIF_RSP_OKAY);
 548                         }
 549                 }
 550
 551                 /* Remember the error: invalidate all subsequent fragments. */
 552                 err = newerr;
 553         }
 554
 555         if (skb_has_frag_list(skb) && !first_shinfo) {
 556                 first_shinfo = skb_shinfo(skb);
 557                 shinfo = skb_shinfo(skb_shinfo(skb)->frag_list);
 558                 nr_frags = shinfo->nr_frags;
 559
 560                 goto check_frags;
 561         }
 562
 563         *gopp_map = gop_map;
 564         return err;
 565 }
 566
 567 static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
 568 {
 569         struct skb_shared_info *shinfo = skb_shinfo(skb);
 570         int nr_frags = shinfo->nr_frags;
 571         int i;
 572         u16 prev_pending_idx = INVALID_PENDING_IDX;
 573
 574         for (i = 0; i < nr_frags; i++) {
 575                 skb_frag_t *frag = shinfo->frags + i;
 576                 struct xen_netif_tx_request *txp;
 577                 struct page *page;
 578                 u16 pending_idx;
 579
 580                 pending_idx = frag_get_pending_idx(frag);
 581
 582                 /* If this is not the first frag, chain it to the previous*/
 583                 if (prev_pending_idx == INVALID_PENDING_IDX)
 584                         skb_shinfo(skb)->destructor_arg =
 585                                 &callback_param(queue, pending_idx);
 586                 else
 587                         callback_param(queue, prev_pending_idx).ctx =
 588                                 &callback_param(queue, pending_idx);
 589
 590                 callback_param(queue, pending_idx).ctx = NULL;
 591                 prev_pending_idx = pending_idx;
 592
 593                 txp = &queue->pending_tx_info[pending_idx].req;
 594                 page = virt_to_page(idx_to_kaddr(queue, pending_idx));
 595                 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
 596                 skb->len += txp->size;
 597                 skb->data_len += txp->size;
 598                 skb->truesize += txp->size;
 599
 600                 /* Take an extra reference to offset network stack's put_page */
 601                 get_page(queue->mmap_pages[pending_idx]);
 602         }
 603 }
 604
 605 static int xenvif_get_extras(struct xenvif_queue *queue,
 606                              struct xen_netif_extra_info *extras,
 607                              unsigned int *extra_count,
 608                              int work_to_do)
 609 {
 610         struct xen_netif_extra_info extra;
 611         RING_IDX cons = queue->tx.req_cons;
 612
 613         do {
 614                 if (unlikely(work_to_do-- <= 0)) {
 615                         netdev_err(queue->vif->dev, "Missing extra info\n");
 616                         xenvif_fatal_tx_err(queue->vif);
 617                         return -EBADR;
 618                 }
 619
 620                 RING_COPY_REQUEST(&queue->tx, cons, &extra);
 621
 622                 queue->tx.req_cons = ++cons;
 623                 (*extra_count)++;
 624
 625                 if (unlikely(!extra.type ||
 626                              extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 627                         netdev_err(queue->vif->dev,
 628                                    "Invalid extra type: %d\n", extra.type);
 629                         xenvif_fatal_tx_err(queue->vif);
 630                         return -EINVAL;
 631                 }
 632
 633                 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
 634         } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
 635
 636         return work_to_do;
 637 }
 638
 639 static int xenvif_set_skb_gso(struct xenvif *vif,
 640                               struct sk_buff *skb,
 641                               struct xen_netif_extra_info *gso)
 642 {
 643         if (!gso->u.gso.size) {
 644                 netdev_err(vif->dev, "GSO size must not be zero.\n");
 645                 xenvif_fatal_tx_err(vif);
 646                 return -EINVAL;
 647         }
 648
 649         switch (gso->u.gso.type) {
 650         case XEN_NETIF_GSO_TYPE_TCPV4:
 651                 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 652                 break;
 653         case XEN_NETIF_GSO_TYPE_TCPV6:
 654                 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 655                 break;
 656         default:
 657                 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
 658                 xenvif_fatal_tx_err(vif);
 659                 return -EINVAL;
 660         }
 661
 662         skb_shinfo(skb)->gso_size = gso->u.gso.size;
 663         /* gso_segs will be calculated later */
 664
 665         return 0;
 666 }
 667
 668 static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
 669 {
 670         bool recalculate_partial_csum = false;
 671
 672         /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 673          * peers can fail to set NETRXF_csum_blank when sending a GSO
 674          * frame. In this case force the SKB to CHECKSUM_PARTIAL and
 675          * recalculate the partial checksum.
 676          */
 677         if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
 678                 queue->stats.rx_gso_checksum_fixup++;
 679                 skb->ip_summed = CHECKSUM_PARTIAL;
 680                 recalculate_partial_csum = true;
 681         }
 682
 683         /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
 684         if (skb->ip_summed != CHECKSUM_PARTIAL)
 685                 return 0;
 686
 687         return skb_checksum_setup(skb, recalculate_partial_csum);
 688 }
 689
 690 static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
 691 {
 692         u64 now = get_jiffies_64();
 693         u64 next_credit = queue->credit_window_start +
 694                 msecs_to_jiffies(queue->credit_usec / 1000);
 695
 696         /* Timer could already be pending in rare cases. */
 697         if (timer_pending(&queue->credit_timeout)) {
 698                 queue->rate_limited = true;
 699                 return true;
 700         }
 701
 702         /* Passed the point where we can replenish credit? */
 703         if (time_after_eq64(now, next_credit)) {
 704                 queue->credit_window_start = now;
 705                 tx_add_credit(queue);
 706         }
 707
 708         /* Still too big to send right now? Set a callback. */
 709         if (size > queue->remaining_credit) {
 710                 mod_timer(&queue->credit_timeout,
 711                           next_credit);
 712                 queue->credit_window_start = next_credit;
 713                 queue->rate_limited = true;
 714
 715                 return true;
 716         }
 717
 718         return false;
 719 }
 720
 721 /* No locking is required in xenvif_mcast_add/del() as they are
 722  * only ever invoked from NAPI poll. An RCU list is used because
 723  * xenvif_mcast_match() is called asynchronously, during start_xmit.
 724  */
 725
 726 static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
 727 {
 728         struct xenvif_mcast_addr *mcast;
 729
 730         if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
 731                 if (net_ratelimit())
 732                         netdev_err(vif->dev,
 733                                    "Too many multicast addresses\n");
 734                 return -ENOSPC;
 735         }
 736
 737         mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
 738         if (!mcast)
 739                 return -ENOMEM;
 740
 741         ether_addr_copy(mcast->addr, addr);
 742         list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
 743         vif->fe_mcast_count++;
 744
 745         return 0;
 746 }
 747
 748 static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
 749 {
 750         struct xenvif_mcast_addr *mcast;
 751
 752         list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
 753                 if (ether_addr_equal(addr, mcast->addr)) {
 754                         --vif->fe_mcast_count;
 755                         list_del_rcu(&mcast->entry);
 756                         kfree_rcu(mcast, rcu);
 757                         break;
 758                 }
 759         }
 760 }
 761
 762 bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
 763 {
 764         struct xenvif_mcast_addr *mcast;
 765
 766         rcu_read_lock();
 767         list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
 768                 if (ether_addr_equal(addr, mcast->addr)) {
 769                         rcu_read_unlock();
 770                         return true;
 771                 }
 772         }
 773         rcu_read_unlock();
 774
 775         return false;
 776 }
 777
 778 void xenvif_mcast_addr_list_free(struct xenvif *vif)
 779 {
 780         /* No need for locking or RCU here. NAPI poll and TX queue
 781          * are stopped.
 782          */
 783         while (!list_empty(&vif->fe_mcast_addr)) {
 784                 struct xenvif_mcast_addr *mcast;
 785
 786                 mcast = list_first_entry(&vif->fe_mcast_addr,
 787                                          struct xenvif_mcast_addr,
 788                                          entry);
 789                 --vif->fe_mcast_count;
 790                 list_del(&mcast->entry);
 791                 kfree(mcast);
 792         }
 793 }
 794
 795 static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 796                                      int budget,
 797                                      unsigned *copy_ops,
 798                                      unsigned *map_ops)
 799 {
 800         struct gnttab_map_grant_ref *gop = queue->tx_map_ops;
 801         struct sk_buff *skb, *nskb;
 802         int ret;
 803         unsigned int frag_overflow;
 804
 805         while (skb_queue_len(&queue->tx_queue) < budget) {
 806                 struct xen_netif_tx_request txreq;
 807                 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
 808                 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
 809                 unsigned int extra_count;
 810                 u16 pending_idx;
 811                 RING_IDX idx;
 812                 int work_to_do;
 813                 unsigned int data_len;
 814                 pending_ring_idx_t index;
 815
 816                 if (queue->tx.sring->req_prod - queue->tx.req_cons >
 817                     XEN_NETIF_TX_RING_SIZE) {
 818                         netdev_err(queue->vif->dev,
 819                                    "Impossible number of requests. "
 820                                    "req_prod %d, req_cons %d, size %ld\n",
 821                                    queue->tx.sring->req_prod, queue->tx.req_cons,
 822                                    XEN_NETIF_TX_RING_SIZE);
 823                         xenvif_fatal_tx_err(queue->vif);
 824                         break;
 825                 }
 826
 827                 work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
 828                 if (!work_to_do)
 829                         break;
 830
 831                 idx = queue->tx.req_cons;
 832                 rmb(); /* Ensure that we see the request before we copy it. */
 833                 RING_COPY_REQUEST(&queue->tx, idx, &txreq);
 834
 835                 /* Credit-based scheduling. */
 836                 if (txreq.size > queue->remaining_credit &&
 837                     tx_credit_exceeded(queue, txreq.size))
 838                         break;
 839
 840                 queue->remaining_credit -= txreq.size;
 841
 842                 work_to_do--;
 843                 queue->tx.req_cons = ++idx;
 844
 845                 memset(extras, 0, sizeof(extras));
 846                 extra_count = 0;
 847                 if (txreq.flags & XEN_NETTXF_extra_info) {
 848                         work_to_do = xenvif_get_extras(queue, extras,
 849                                                        &extra_count,
 850                                                        work_to_do);
 851                         idx = queue->tx.req_cons;
 852                         if (unlikely(work_to_do < 0))
 853                                 break;
 854                 }
 855
 856                 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
 857                         struct xen_netif_extra_info *extra;
 858
 859                         extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
 860                         ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
 861
 862                         make_tx_response(queue, &txreq, extra_count,
 863                                          (ret == 0) ?
 864                                          XEN_NETIF_RSP_OKAY :
 865                                          XEN_NETIF_RSP_ERROR);
 866                         push_tx_responses(queue);
 867                         continue;
 868                 }
 869
 870                 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
 871                         struct xen_netif_extra_info *extra;
 872
 873                         extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
 874                         xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
 875
 876                         make_tx_response(queue, &txreq, extra_count,
 877                                          XEN_NETIF_RSP_OKAY);
 878                         push_tx_responses(queue);
 879                         continue;
 880                 }
 881
 882                 ret = xenvif_count_requests(queue, &txreq, extra_count,
 883                                             txfrags, work_to_do);
 884                 if (unlikely(ret < 0))
 885                         break;
 886
 887                 idx += ret;
 888
 889                 if (unlikely(txreq.size < ETH_HLEN)) {
 890                         netdev_dbg(queue->vif->dev,
 891                                    "Bad packet size: %d\n", txreq.size);
 892                         xenvif_tx_err(queue, &txreq, extra_count, idx);
 893                         break;
 894                 }
 895
 896                 /* No crossing a page as the payload mustn't fragment. */
 897                 if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
 898                         netdev_err(queue->vif->dev,
 899                                    "txreq.offset: %u, size: %u, end: %lu\n",
 900                                    txreq.offset, txreq.size,
 901                                    (unsigned long)(txreq.offset&~XEN_PAGE_MASK) + txreq.size);
 902                         xenvif_fatal_tx_err(queue->vif);
 903                         break;
 904                 }
 905
 906                 index = pending_index(queue->pending_cons);
 907                 pending_idx = queue->pending_ring[index];
 908
 909                 data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
 910                             ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
 911                         XEN_NETBACK_TX_COPY_LEN : txreq.size;
 912
 913                 skb = xenvif_alloc_skb(data_len);
 914                 if (unlikely(skb == NULL)) {
 915                         netdev_dbg(queue->vif->dev,
 916                                    "Can't allocate a skb in start_xmit.\n");
 917                         xenvif_tx_err(queue, &txreq, extra_count, idx);
 918                         break;
 919                 }
 920
 921                 skb_shinfo(skb)->nr_frags = ret;
 922                 if (data_len < txreq.size)
 923                         skb_shinfo(skb)->nr_frags++;
 924                 /* At this point shinfo->nr_frags is in fact the number of
 925                  * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
 926                  */
 927                 frag_overflow = 0;
 928                 nskb = NULL;
 929                 if (skb_shinfo(skb)->nr_frags > MAX_SKB_FRAGS) {
 930                         frag_overflow = skb_shinfo(skb)->nr_frags - MAX_SKB_FRAGS;
 931                         BUG_ON(frag_overflow > MAX_SKB_FRAGS);
 932                         skb_shinfo(skb)->nr_frags = MAX_SKB_FRAGS;
 933                         nskb = xenvif_alloc_skb(0);
 934                         if (unlikely(nskb == NULL)) {
 935                                 skb_shinfo(skb)->nr_frags = 0;
 936                                 kfree_skb(skb);
 937                                 xenvif_tx_err(queue, &txreq, extra_count, idx);
 938                                 if (net_ratelimit())
 939                                         netdev_err(queue->vif->dev,
 940                                                    "Can't allocate the frag_list skb.\n");
 941                                 break;
 942                         }
 943                 }
 944
 945                 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
 946                         struct xen_netif_extra_info *gso;
 947                         gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
 948
 949                         if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
 950                                 /* Failure in xenvif_set_skb_gso is fatal. */
 951                                 skb_shinfo(skb)->nr_frags = 0;
 952                                 kfree_skb(skb);
 953                                 kfree_skb(nskb);
 954                                 break;
 955                         }
 956                 }
 957
 958                 if (extras[XEN_NETIF_EXTRA_TYPE_HASH - 1].type) {
 959                         struct xen_netif_extra_info *extra;
 960                         enum pkt_hash_types type = PKT_HASH_TYPE_NONE;
 961
 962                         extra = &extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
 963
 964                         switch (extra->u.hash.type) {
 965                         case _XEN_NETIF_CTRL_HASH_TYPE_IPV4:
 966                         case _XEN_NETIF_CTRL_HASH_TYPE_IPV6:
 967                                 type = PKT_HASH_TYPE_L3;
 968                                 break;
 969
 970                         case _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP:
 971                         case _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP:
 972                                 type = PKT_HASH_TYPE_L4;
 973                                 break;
 974
 975                         default:
 976                                 break;
 977                         }
 978
 979                         if (type != PKT_HASH_TYPE_NONE)
 980                                 skb_set_hash(skb,
 981                                              *(u32 *)extra->u.hash.value,
 982                                              type);
 983                 }
 984
 985                 XENVIF_TX_CB(skb)->pending_idx = pending_idx;
 986
 987                 __skb_put(skb, data_len);
 988                 queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
 989                 queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
 990                 queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
 991
 992                 queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
 993                         virt_to_gfn(skb->data);
 994                 queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
 995                 queue->tx_copy_ops[*copy_ops].dest.offset =
 996                         offset_in_page(skb->data) & ~XEN_PAGE_MASK;
 997
 998                 queue->tx_copy_ops[*copy_ops].len = data_len;
 999                 queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
1000
1001                 (*copy_ops)++;
1002
1003                 if (data_len < txreq.size) {
1004                         frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1005                                              pending_idx);
1006                         xenvif_tx_create_map_op(queue, pending_idx, &txreq,
1007                                                 extra_count, gop);
1008                         gop++;
1009                 } else {
1010                         frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1011                                              INVALID_PENDING_IDX);
1012                         memcpy(&queue->pending_tx_info[pending_idx].req,
1013                                &txreq, sizeof(txreq));
1014                         queue->pending_tx_info[pending_idx].extra_count =
1015                                 extra_count;
1016                 }
1017
1018                 queue->pending_cons++;
1019
1020                 gop = xenvif_get_requests(queue, skb, txfrags, gop,
1021                                           frag_overflow, nskb);
1022
1023                 __skb_queue_tail(&queue->tx_queue, skb);
1024
1025                 queue->tx.req_cons = idx;
1026
1027                 if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
1028                     (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
1029                         break;
1030         }
1031
1032         (*map_ops) = gop - queue->tx_map_ops;
1033         return;
1034 }
1035
1036 /* Consolidate skb with a frag_list into a brand new one with local pages on
1037  * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1038  */
1039 static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1040 {
1041         unsigned int offset = skb_headlen(skb);
1042         skb_frag_t frags[MAX_SKB_FRAGS];
1043         int i, f;
1044         struct ubuf_info *uarg;
1045         struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1046
1047         queue->stats.tx_zerocopy_sent += 2;
1048         queue->stats.tx_frag_overflow++;
1049
1050         xenvif_fill_frags(queue, nskb);
1051         /* Subtract frags size, we will correct it later */
1052         skb->truesize -= skb->data_len;
1053         skb->len += nskb->len;
1054         skb->data_len += nskb->len;
1055
1056         /* create a brand new frags array and coalesce there */
1057         for (i = 0; offset < skb->len; i++) {
1058                 struct page *page;
1059                 unsigned int len;
1060
1061                 BUG_ON(i >= MAX_SKB_FRAGS);
1062                 page = alloc_page(GFP_ATOMIC);
1063                 if (!page) {
1064                         int j;
1065                         skb->truesize += skb->data_len;
1066                         for (j = 0; j < i; j++)
1067                                 put_page(skb_frag_page(&frags[j]));
1068                         return -ENOMEM;
1069                 }
1070
1071                 if (offset + PAGE_SIZE < skb->len)
1072                         len = PAGE_SIZE;
1073                 else
1074                         len = skb->len - offset;
1075                 if (skb_copy_bits(skb, offset, page_address(page), len))
1076                         BUG();
1077
1078                 offset += len;
1079                 __skb_frag_set_page(&frags[i], page);
1080                 skb_frag_off_set(&frags[i], 0);
1081                 skb_frag_size_set(&frags[i], len);
1082         }
1083
1084         /* Release all the original (foreign) frags. */
1085         for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
1086                 skb_frag_unref(skb, f);
1087         uarg = skb_shinfo(skb)->destructor_arg;
1088         /* increase inflight counter to offset decrement in callback */
1089         atomic_inc(&queue->inflight_packets);
1090         uarg->callback(uarg, true);
1091         skb_shinfo(skb)->destructor_arg = NULL;
1092
1093         /* Fill the skb with the new (local) frags. */
1094         memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
1095         skb_shinfo(skb)->nr_frags = i;
1096         skb->truesize += i * PAGE_SIZE;
1097
1098         return 0;
1099 }
1100
1101 static int xenvif_tx_submit(struct xenvif_queue *queue)
1102 {
1103         struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1104         struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1105         struct sk_buff *skb;
1106         int work_done = 0;
1107
1108         while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1109                 struct xen_netif_tx_request *txp;
1110                 u16 pending_idx;
1111                 unsigned data_len;
1112
1113                 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1114                 txp = &queue->pending_tx_info[pending_idx].req;
1115
1116                 /* Check the remap error code. */
1117                 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1118                         /* If there was an error, xenvif_tx_check_gop is
1119                          * expected to release all the frags which were mapped,
1120                          * so kfree_skb shouldn't do it again
1121                          */
1122                         skb_shinfo(skb)->nr_frags = 0;
1123                         if (skb_has_frag_list(skb)) {
1124                                 struct sk_buff *nskb =
1125                                                 skb_shinfo(skb)->frag_list;
1126                                 skb_shinfo(nskb)->nr_frags = 0;
1127                         }
1128                         kfree_skb(skb);
1129                         continue;
1130                 }
1131
1132                 data_len = skb->len;
1133                 callback_param(queue, pending_idx).ctx = NULL;
1134                 if (data_len < txp->size) {
1135                         /* Append the packet payload as a fragment. */
1136                         txp->offset += data_len;
1137                         txp->size -= data_len;
1138                 } else {
1139                         /* Schedule a response immediately. */
1140                         xenvif_idx_release(queue, pending_idx,
1141                                            XEN_NETIF_RSP_OKAY);
1142                 }
1143
1144                 if (txp->flags & XEN_NETTXF_csum_blank)
1145                         skb->ip_summed = CHECKSUM_PARTIAL;
1146                 else if (txp->flags & XEN_NETTXF_data_validated)
1147                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1148
1149                 xenvif_fill_frags(queue, skb);
1150
1151                 if (unlikely(skb_has_frag_list(skb))) {
1152                         struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1153                         xenvif_skb_zerocopy_prepare(queue, nskb);
1154                         if (xenvif_handle_frag_list(queue, skb)) {
1155                                 if (net_ratelimit())
1156                                         netdev_err(queue->vif->dev,
1157                                                    "Not enough memory to consolidate frag_list!\n");
1158                                 xenvif_skb_zerocopy_prepare(queue, skb);
1159                                 kfree_skb(skb);
1160                                 continue;
1161                         }
1162                         /* Copied all the bits from the frag list -- free it. */
1163                         skb_frag_list_init(skb);
1164                         kfree_skb(nskb);
1165                 }
1166
1167                 skb->dev      = queue->vif->dev;
1168                 skb->protocol = eth_type_trans(skb, skb->dev);
1169                 skb_reset_network_header(skb);
1170
1171                 if (checksum_setup(queue, skb)) {
1172                         netdev_dbg(queue->vif->dev,
1173                                    "Can't setup checksum in net_tx_action\n");
1174                         /* We have to set this flag to trigger the callback */
1175                         if (skb_shinfo(skb)->destructor_arg)
1176                                 xenvif_skb_zerocopy_prepare(queue, skb);
1177                         kfree_skb(skb);
1178                         continue;
1179                 }
1180
1181                 skb_probe_transport_header(skb);
1182
1183                 /* If the packet is GSO then we will have just set up the
1184                  * transport header offset in checksum_setup so it's now
1185                  * straightforward to calculate gso_segs.
1186                  */
1187                 if (skb_is_gso(skb)) {
1188                         int mss, hdrlen;
1189
1190                         /* GSO implies having the L4 header. */
1191                         WARN_ON_ONCE(!skb_transport_header_was_set(skb));
1192                         if (unlikely(!skb_transport_header_was_set(skb))) {
1193                                 kfree_skb(skb);
1194                                 continue;
1195                         }
1196
1197                         mss = skb_shinfo(skb)->gso_size;
1198                         hdrlen = skb_transport_header(skb) -
1199                                 skb_mac_header(skb) +
1200                                 tcp_hdrlen(skb);
1201
1202                         skb_shinfo(skb)->gso_segs =
1203                                 DIV_ROUND_UP(skb->len - hdrlen, mss);
1204                 }
1205
1206                 queue->stats.rx_bytes += skb->len;
1207                 queue->stats.rx_packets++;
1208
1209                 work_done++;
1210
1211                 /* Set this flag right before netif_receive_skb, otherwise
1212                  * someone might think this packet already left netback, and
1213                  * do a skb_copy_ubufs while we are still in control of the
1214                  * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1215                  */
1216                 if (skb_shinfo(skb)->destructor_arg) {
1217                         xenvif_skb_zerocopy_prepare(queue, skb);
1218                         queue->stats.tx_zerocopy_sent++;
1219                 }
1220
1221                 netif_receive_skb(skb);
1222         }
1223
1224         return work_done;
1225 }
1226
1227 void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
1228 {
1229         unsigned long flags;
1230         pending_ring_idx_t index;
1231         struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1232
1233         /* This is the only place where we grab this lock, to protect callbacks
1234          * from each other.
1235          */
1236         spin_lock_irqsave(&queue->callback_lock, flags);
1237         do {
1238                 u16 pending_idx = ubuf->desc;
1239                 ubuf = (struct ubuf_info *) ubuf->ctx;
1240                 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1241                         MAX_PENDING_REQS);
1242                 index = pending_index(queue->dealloc_prod);
1243                 queue->dealloc_ring[index] = pending_idx;
1244                 /* Sync with xenvif_tx_dealloc_action:
1245                  * insert idx then incr producer.
1246                  */
1247                 smp_wmb();
1248                 queue->dealloc_prod++;
1249         } while (ubuf);
1250         spin_unlock_irqrestore(&queue->callback_lock, flags);
1251
1252         if (likely(zerocopy_success))
1253                 queue->stats.tx_zerocopy_success++;
1254         else
1255                 queue->stats.tx_zerocopy_fail++;
1256         xenvif_skb_zerocopy_complete(queue);
1257 }
1258
1259 static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1260 {
1261         struct gnttab_unmap_grant_ref *gop;
1262         pending_ring_idx_t dc, dp;
1263         u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1264         unsigned int i = 0;
1265
1266         dc = queue->dealloc_cons;
1267         gop = queue->tx_unmap_ops;
1268
1269         /* Free up any grants we have finished using */
1270         do {
1271                 dp = queue->dealloc_prod;
1272
1273                 /* Ensure we see all indices enqueued by all
1274                  * xenvif_zerocopy_callback().
1275                  */
1276                 smp_rmb();
1277
1278                 while (dc != dp) {
1279                         BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS);
1280                         pending_idx =
1281                                 queue->dealloc_ring[pending_index(dc++)];
1282
1283                         pending_idx_release[gop - queue->tx_unmap_ops] =
1284                                 pending_idx;
1285                         queue->pages_to_unmap[gop - queue->tx_unmap_ops] =
1286                                 queue->mmap_pages[pending_idx];
1287                         gnttab_set_unmap_op(gop,
1288                                             idx_to_kaddr(queue, pending_idx),
1289                                             GNTMAP_host_map,
1290                                             queue->grant_tx_handle[pending_idx]);
1291                         xenvif_grant_handle_reset(queue, pending_idx);
1292                         ++gop;
1293                 }
1294
1295         } while (dp != queue->dealloc_prod);
1296
1297         queue->dealloc_cons = dc;
1298
1299         if (gop - queue->tx_unmap_ops > 0) {
1300                 int ret;
1301                 ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1302                                         NULL,
1303                                         queue->pages_to_unmap,
1304                                         gop - queue->tx_unmap_ops);
1305                 if (ret) {
1306                         netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tu ret %d\n",
1307                                    gop - queue->tx_unmap_ops, ret);
1308                         for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1309                                 if (gop[i].status != GNTST_okay)
1310                                         netdev_err(queue->vif->dev,
1311                                                    " host_addr: 0x%llx handle: 0x%x status: %d\n",
1312                                                    gop[i].host_addr,
1313                                                    gop[i].handle,
1314                                                    gop[i].status);
1315                         }
1316                         BUG();
1317                 }
1318         }
1319
1320         for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1321                 xenvif_idx_release(queue, pending_idx_release[i],
1322                                    XEN_NETIF_RSP_OKAY);
1323 }
1324
1325
1326 /* Called after netfront has transmitted */
1327 int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1328 {
1329         unsigned nr_mops, nr_cops = 0;
1330         int work_done, ret;
1331
1332         if (unlikely(!tx_work_todo(queue)))
1333                 return 0;
1334
1335         xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1336
1337         if (nr_cops == 0)
1338                 return 0;
1339
1340         gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1341         if (nr_mops != 0) {
1342                 ret = gnttab_map_refs(queue->tx_map_ops,
1343                                       NULL,
1344                                       queue->pages_to_map,
1345                                       nr_mops);
1346                 BUG_ON(ret);
1347         }
1348
1349         work_done = xenvif_tx_submit(queue);
1350
1351         return work_done;
1352 }
1353
1354 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1355                                u8 status)
1356 {
1357         struct pending_tx_info *pending_tx_info;
1358         pending_ring_idx_t index;
1359         unsigned long flags;
1360
1361         pending_tx_info = &queue->pending_tx_info[pending_idx];
1362
1363         spin_lock_irqsave(&queue->response_lock, flags);
1364
1365         make_tx_response(queue, &pending_tx_info->req,
1366                          pending_tx_info->extra_count, status);
1367
1368         /* Release the pending index before pusing the Tx response so
1369          * its available before a new Tx request is pushed by the
1370          * frontend.
1371          */
1372         index = pending_index(queue->pending_prod++);
1373         queue->pending_ring[index] = pending_idx;
1374
1375         push_tx_responses(queue);
1376
1377         spin_unlock_irqrestore(&queue->response_lock, flags);
1378 }
1379
1380
1381 static void make_tx_response(struct xenvif_queue *queue,
1382                              struct xen_netif_tx_request *txp,
1383                              unsigned int extra_count,
1384                              s8       st)
1385 {
1386         RING_IDX i = queue->tx.rsp_prod_pvt;
1387         struct xen_netif_tx_response *resp;
1388
1389         resp = RING_GET_RESPONSE(&queue->tx, i);
1390         resp->id     = txp->id;
1391         resp->status = st;
1392
1393         while (extra_count-- != 0)
1394                 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1395
1396         queue->tx.rsp_prod_pvt = ++i;
1397 }
1398
1399 static void push_tx_responses(struct xenvif_queue *queue)
1400 {
1401         int notify;
1402
1403         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1404         if (notify)
1405                 notify_remote_via_irq(queue->tx_irq);
1406 }
1407
1408 void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1409 {
1410         int ret;
1411         struct gnttab_unmap_grant_ref tx_unmap_op;
1412
1413         gnttab_set_unmap_op(&tx_unmap_op,
1414                             idx_to_kaddr(queue, pending_idx),
1415                             GNTMAP_host_map,
1416                             queue->grant_tx_handle[pending_idx]);
1417         xenvif_grant_handle_reset(queue, pending_idx);
1418
1419         ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1420                                 &queue->mmap_pages[pending_idx], 1);
1421         if (ret) {
1422                 netdev_err(queue->vif->dev,
1423                            "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: 0x%x status: %d\n",
1424                            ret,
1425                            pending_idx,
1426                            tx_unmap_op.host_addr,
1427                            tx_unmap_op.handle,
1428                            tx_unmap_op.status);
1429                 BUG();
1430         }
1431 }
1432
1433 static inline int tx_work_todo(struct xenvif_queue *queue)
1434 {
1435         if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1436                 return 1;
1437
1438         return 0;
1439 }
1440
1441 static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1442 {
1443         return queue->dealloc_cons != queue->dealloc_prod;
1444 }
1445
1446 void xenvif_unmap_frontend_data_rings(struct xenvif_queue *queue)
1447 {
1448         if (queue->tx.sring)
1449                 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1450                                         queue->tx.sring);
1451         if (queue->rx.sring)
1452                 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1453                                         queue->rx.sring);
1454 }
1455
1456 int xenvif_map_frontend_data_rings(struct xenvif_queue *queue,
1457                                    grant_ref_t tx_ring_ref,
1458                                    grant_ref_t rx_ring_ref)
1459 {
1460         void *addr;
1461         struct xen_netif_tx_sring *txs;
1462         struct xen_netif_rx_sring *rxs;
1463         RING_IDX rsp_prod, req_prod;
1464         int err = -ENOMEM;
1465
1466         err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1467                                      &tx_ring_ref, 1, &addr);
1468         if (err)
1469                 goto err;
1470
1471         txs = (struct xen_netif_tx_sring *)addr;
1472         rsp_prod = READ_ONCE(txs->rsp_prod);
1473         req_prod = READ_ONCE(txs->req_prod);
1474
1475         BACK_RING_ATTACH(&queue->tx, txs, rsp_prod, XEN_PAGE_SIZE);
1476
1477         err = -EIO;
1478         if (req_prod - rsp_prod > RING_SIZE(&queue->tx))
1479                 goto err;
1480
1481         err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1482                                      &rx_ring_ref, 1, &addr);
1483         if (err)
1484                 goto err;
1485
1486         rxs = (struct xen_netif_rx_sring *)addr;
1487         rsp_prod = READ_ONCE(rxs->rsp_prod);
1488         req_prod = READ_ONCE(rxs->req_prod);
1489
1490         BACK_RING_ATTACH(&queue->rx, rxs, rsp_prod, XEN_PAGE_SIZE);
1491
1492         err = -EIO;
1493         if (req_prod - rsp_prod > RING_SIZE(&queue->rx))
1494                 goto err;
1495
1496         return 0;
1497
1498 err:
1499         xenvif_unmap_frontend_data_rings(queue);
1500         return err;
1501 }
1502
1503 static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
1504 {
1505         /* Dealloc thread must remain running until all inflight
1506          * packets complete.
1507          */
1508         return kthread_should_stop() &&
1509                 !atomic_read(&queue->inflight_packets);
1510 }
1511
1512 int xenvif_dealloc_kthread(void *data)
1513 {
1514         struct xenvif_queue *queue = data;
1515
1516         for (;;) {
1517                 wait_event_interruptible(queue->dealloc_wq,
1518                                          tx_dealloc_work_todo(queue) ||
1519                                          xenvif_dealloc_kthread_should_stop(queue));
1520                 if (xenvif_dealloc_kthread_should_stop(queue))
1521                         break;
1522
1523                 xenvif_tx_dealloc_action(queue);
1524                 cond_resched();
1525         }
1526
1527         /* Unmap anything remaining*/
1528         if (tx_dealloc_work_todo(queue))
1529                 xenvif_tx_dealloc_action(queue);
1530
1531         return 0;
1532 }
1533
1534 static void make_ctrl_response(struct xenvif *vif,
1535                                const struct xen_netif_ctrl_request *req,
1536                                u32 status, u32 data)
1537 {
1538         RING_IDX idx = vif->ctrl.rsp_prod_pvt;
1539         struct xen_netif_ctrl_response rsp = {
1540                 .id = req->id,
1541                 .type = req->type,
1542                 .status = status,
1543                 .data = data,
1544         };
1545
1546         *RING_GET_RESPONSE(&vif->ctrl, idx) = rsp;
1547         vif->ctrl.rsp_prod_pvt = ++idx;
1548 }
1549
1550 static void push_ctrl_response(struct xenvif *vif)
1551 {
1552         int notify;
1553
1554         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->ctrl, notify);
1555         if (notify)
1556                 notify_remote_via_irq(vif->ctrl_irq);
1557 }
1558
1559 static void process_ctrl_request(struct xenvif *vif,
1560                                  const struct xen_netif_ctrl_request *req)
1561 {
1562         u32 status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED;
1563         u32 data = 0;
1564
1565         switch (req->type) {
1566         case XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM:
1567                 status = xenvif_set_hash_alg(vif, req->data[0]);
1568                 break;
1569
1570         case XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS:
1571                 status = xenvif_get_hash_flags(vif, &data);
1572                 break;
1573
1574         case XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS:
1575                 status = xenvif_set_hash_flags(vif, req->data[0]);
1576                 break;
1577
1578         case XEN_NETIF_CTRL_TYPE_SET_HASH_KEY:
1579                 status = xenvif_set_hash_key(vif, req->data[0],
1580                                              req->data[1]);
1581                 break;
1582
1583         case XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE:
1584                 status = XEN_NETIF_CTRL_STATUS_SUCCESS;
1585                 data = XEN_NETBK_MAX_HASH_MAPPING_SIZE;
1586                 break;
1587
1588         case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE:
1589                 status = xenvif_set_hash_mapping_size(vif,
1590                                                       req->data[0]);
1591                 break;
1592
1593         case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING:
1594                 status = xenvif_set_hash_mapping(vif, req->data[0],
1595                                                  req->data[1],
1596                                                  req->data[2]);
1597                 break;
1598
1599         default:
1600                 break;
1601         }
1602
1603         make_ctrl_response(vif, req, status, data);
1604         push_ctrl_response(vif);
1605 }
1606
1607 static void xenvif_ctrl_action(struct xenvif *vif)
1608 {
1609         for (;;) {
1610                 RING_IDX req_prod, req_cons;
1611
1612                 req_prod = vif->ctrl.sring->req_prod;
1613                 req_cons = vif->ctrl.req_cons;
1614
1615                 /* Make sure we can see requests before we process them. */
1616                 rmb();
1617
1618                 if (req_cons == req_prod)
1619                         break;
1620
1621                 while (req_cons != req_prod) {
1622                         struct xen_netif_ctrl_request req;
1623
1624                         RING_COPY_REQUEST(&vif->ctrl, req_cons, &req);
1625                         req_cons++;
1626
1627                         process_ctrl_request(vif, &req);
1628                 }
1629
1630                 vif->ctrl.req_cons = req_cons;
1631                 vif->ctrl.sring->req_event = req_cons + 1;
1632         }
1633 }
1634
1635 static bool xenvif_ctrl_work_todo(struct xenvif *vif)
1636 {
1637         if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->ctrl)))
1638                 return true;
1639
1640         return false;
1641 }
1642
1643 irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data)
1644 {
1645         struct xenvif *vif = data;
1646
1647         while (xenvif_ctrl_work_todo(vif))
1648                 xenvif_ctrl_action(vif);
1649
1650         return IRQ_HANDLED;
1651 }
1652
1653 static int __init netback_init(void)
1654 {
1655         int rc = 0;
1656
1657         if (!xen_domain())
1658                 return -ENODEV;
1659
1660         /* Allow as many queues as there are CPUs but max. 8 if user has not
1661          * specified a value.
1662          */
1663         if (xenvif_max_queues == 0)
1664                 xenvif_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
1665                                           num_online_cpus());
1666
1667         if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1668                 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1669                         fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1670                 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1671         }
1672
1673         rc = xenvif_xenbus_init();
1674         if (rc)
1675                 goto failed_init;
1676
1677 #ifdef CONFIG_DEBUG_FS
1678         xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
1679 #endif /* CONFIG_DEBUG_FS */
1680
1681         return 0;
1682
1683 failed_init:
1684         return rc;
1685 }
1686
1687 module_init(netback_init);
1688
1689 static void __exit netback_fini(void)
1690 {
1691 #ifdef CONFIG_DEBUG_FS
1692         debugfs_remove_recursive(xen_netback_dbg_root);
1693 #endif /* CONFIG_DEBUG_FS */
1694         xenvif_xenbus_fini();
1695 }
1696 module_exit(netback_fini);
1697
1698 MODULE_LICENSE("Dual BSD/GPL");
1699 MODULE_ALIAS("xen-backend:vif");