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 void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx);
 116
 117 static inline int tx_work_todo(struct xenvif_queue *queue);
 118
 119 static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
 120                                        u16 idx)
 121 {
 122         return page_to_pfn(queue->mmap_pages[idx]);
 123 }
 124
 125 static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
 126                                          u16 idx)
 127 {
 128         return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
 129 }
 130
 131 #define callback_param(vif, pending_idx) \
 132         (vif->pending_tx_info[pending_idx].callback_struct)
 133
 134 /* Find the containing VIF's structure from a pointer in pending_tx_info array
 135  */
 136 static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info_msgzc *ubuf)
 137 {
 138         u16 pending_idx = ubuf->desc;
 139         struct pending_tx_info *temp =
 140                 container_of(ubuf, struct pending_tx_info, callback_struct);
 141         return container_of(temp - pending_idx,
 142                             struct xenvif_queue,
 143                             pending_tx_info[0]);
 144 }
 145
 146 static u16 frag_get_pending_idx(skb_frag_t *frag)
 147 {
 148         return (u16)skb_frag_off(frag);
 149 }
 150
 151 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
 152 {
 153         skb_frag_off_set(frag, pending_idx);
 154 }
 155
 156 static inline pending_ring_idx_t pending_index(unsigned i)
 157 {
 158         return i & (MAX_PENDING_REQS-1);
 159 }
 160
 161 void xenvif_kick_thread(struct xenvif_queue *queue)
 162 {
 163         wake_up(&queue->wq);
 164 }
 165
 166 void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
 167 {
 168         int more_to_do;
 169
 170         RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
 171
 172         if (more_to_do)
 173                 napi_schedule(&queue->napi);
 174         else if (atomic_fetch_andnot(NETBK_TX_EOI | NETBK_COMMON_EOI,
 175                                      &queue->eoi_pending) &
 176                  (NETBK_TX_EOI | NETBK_COMMON_EOI))
 177                 xen_irq_lateeoi(queue->tx_irq, 0);
 178 }
 179
 180 static void tx_add_credit(struct xenvif_queue *queue)
 181 {
 182         unsigned long max_burst, max_credit;
 183
 184         /*
 185          * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
 186          * Otherwise the interface can seize up due to insufficient credit.
 187          */
 188         max_burst = max(131072UL, queue->credit_bytes);
 189
 190         /* Take care that adding a new chunk of credit doesn't wrap to zero. */
 191         max_credit = queue->remaining_credit + queue->credit_bytes;
 192         if (max_credit < queue->remaining_credit)
 193                 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
 194
 195         queue->remaining_credit = min(max_credit, max_burst);
 196         queue->rate_limited = false;
 197 }
 198
 199 void xenvif_tx_credit_callback(struct timer_list *t)
 200 {
 201         struct xenvif_queue *queue = from_timer(queue, t, credit_timeout);
 202         tx_add_credit(queue);
 203         xenvif_napi_schedule_or_enable_events(queue);
 204 }
 205
 206 static void xenvif_tx_err(struct xenvif_queue *queue,
 207                           struct xen_netif_tx_request *txp,
 208                           unsigned int extra_count, RING_IDX end)
 209 {
 210         RING_IDX cons = queue->tx.req_cons;
 211         unsigned long flags;
 212
 213         do {
 214                 spin_lock_irqsave(&queue->response_lock, flags);
 215                 make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR);
 216                 push_tx_responses(queue);
 217                 spin_unlock_irqrestore(&queue->response_lock, flags);
 218                 if (cons == end)
 219                         break;
 220                 RING_COPY_REQUEST(&queue->tx, cons++, txp);
 221                 extra_count = 0; /* only the first frag can have extras */
 222         } while (1);
 223         queue->tx.req_cons = cons;
 224 }
 225
 226 static void xenvif_fatal_tx_err(struct xenvif *vif)
 227 {
 228         netdev_err(vif->dev, "fatal error; disabling device\n");
 229         vif->disabled = true;
 230         /* Disable the vif from queue 0's kthread */
 231         if (vif->num_queues)
 232                 xenvif_kick_thread(&vif->queues[0]);
 233 }
 234
 235 static int xenvif_count_requests(struct xenvif_queue *queue,
 236                                  struct xen_netif_tx_request *first,
 237                                  unsigned int extra_count,
 238                                  struct xen_netif_tx_request *txp,
 239                                  int work_to_do)
 240 {
 241         RING_IDX cons = queue->tx.req_cons;
 242         int slots = 0;
 243         int drop_err = 0;
 244         int more_data;
 245
 246         if (!(first->flags & XEN_NETTXF_more_data))
 247                 return 0;
 248
 249         do {
 250                 struct xen_netif_tx_request dropped_tx = { 0 };
 251
 252                 if (slots >= work_to_do) {
 253                         netdev_err(queue->vif->dev,
 254                                    "Asked for %d slots but exceeds this limit\n",
 255                                    work_to_do);
 256                         xenvif_fatal_tx_err(queue->vif);
 257                         return -ENODATA;
 258                 }
 259
 260                 /* This guest is really using too many slots and
 261                  * considered malicious.
 262                  */
 263                 if (unlikely(slots >= fatal_skb_slots)) {
 264                         netdev_err(queue->vif->dev,
 265                                    "Malicious frontend using %d slots, threshold %u\n",
 266                                    slots, fatal_skb_slots);
 267                         xenvif_fatal_tx_err(queue->vif);
 268                         return -E2BIG;
 269                 }
 270
 271                 /* Xen network protocol had implicit dependency on
 272                  * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
 273                  * the historical MAX_SKB_FRAGS value 18 to honor the
 274                  * same behavior as before. Any packet using more than
 275                  * 18 slots but less than fatal_skb_slots slots is
 276                  * dropped
 277                  */
 278                 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
 279                         if (net_ratelimit())
 280                                 netdev_dbg(queue->vif->dev,
 281                                            "Too many slots (%d) exceeding limit (%d), dropping packet\n",
 282                                            slots, XEN_NETBK_LEGACY_SLOTS_MAX);
 283                         drop_err = -E2BIG;
 284                 }
 285
 286                 if (drop_err)
 287                         txp = &dropped_tx;
 288
 289                 RING_COPY_REQUEST(&queue->tx, cons + slots, txp);
 290
 291                 /* If the guest submitted a frame >= 64 KiB then
 292                  * first->size overflowed and following slots will
 293                  * appear to be larger than the frame.
 294                  *
 295                  * This cannot be fatal error as there are buggy
 296                  * frontends that do this.
 297                  *
 298                  * Consume all slots and drop the packet.
 299                  */
 300                 if (!drop_err && txp->size > first->size) {
 301                         if (net_ratelimit())
 302                                 netdev_dbg(queue->vif->dev,
 303                                            "Invalid tx request, slot size %u > remaining size %u\n",
 304                                            txp->size, first->size);
 305                         drop_err = -EIO;
 306                 }
 307
 308                 first->size -= txp->size;
 309                 slots++;
 310
 311                 if (unlikely((txp->offset + txp->size) > XEN_PAGE_SIZE)) {
 312                         netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n",
 313                                  txp->offset, txp->size);
 314                         xenvif_fatal_tx_err(queue->vif);
 315                         return -EINVAL;
 316                 }
 317
 318                 more_data = txp->flags & XEN_NETTXF_more_data;
 319
 320                 if (!drop_err)
 321                         txp++;
 322
 323         } while (more_data);
 324
 325         if (drop_err) {
 326                 xenvif_tx_err(queue, first, extra_count, cons + slots);
 327                 return drop_err;
 328         }
 329
 330         return slots;
 331 }
 332
 333
 334 struct xenvif_tx_cb {
 335         u16 copy_pending_idx[XEN_NETBK_LEGACY_SLOTS_MAX + 1];
 336         u8 copy_count;
 337         u32 split_mask;
 338 };
 339
 340 #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
 341 #define copy_pending_idx(skb, i) (XENVIF_TX_CB(skb)->copy_pending_idx[i])
 342 #define copy_count(skb) (XENVIF_TX_CB(skb)->copy_count)
 343
 344 static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
 345                                            u16 pending_idx,
 346                                            struct xen_netif_tx_request *txp,
 347                                            unsigned int extra_count,
 348                                            struct gnttab_map_grant_ref *mop)
 349 {
 350         queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
 351         gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
 352                           GNTMAP_host_map | GNTMAP_readonly,
 353                           txp->gref, queue->vif->domid);
 354
 355         memcpy(&queue->pending_tx_info[pending_idx].req, txp,
 356                sizeof(*txp));
 357         queue->pending_tx_info[pending_idx].extra_count = extra_count;
 358 }
 359
 360 static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
 361 {
 362         struct sk_buff *skb =
 363                 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
 364                           GFP_ATOMIC | __GFP_NOWARN);
 365
 366         BUILD_BUG_ON(sizeof(*XENVIF_TX_CB(skb)) > sizeof(skb->cb));
 367         if (unlikely(skb == NULL))
 368                 return NULL;
 369
 370         /* Packets passed to netif_rx() must have some headroom. */
 371         skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
 372
 373         /* Initialize it here to avoid later surprises */
 374         skb_shinfo(skb)->destructor_arg = NULL;
 375
 376         return skb;
 377 }
 378
 379 static void xenvif_get_requests(struct xenvif_queue *queue,
 380                                 struct sk_buff *skb,
 381                                 struct xen_netif_tx_request *first,
 382                                 struct xen_netif_tx_request *txfrags,
 383                                 unsigned *copy_ops,
 384                                 unsigned *map_ops,
 385                                 unsigned int frag_overflow,
 386                                 struct sk_buff *nskb,
 387                                 unsigned int extra_count,
 388                                 unsigned int data_len)
 389 {
 390         struct skb_shared_info *shinfo = skb_shinfo(skb);
 391         skb_frag_t *frags = shinfo->frags;
 392         u16 pending_idx;
 393         pending_ring_idx_t index;
 394         unsigned int nr_slots;
 395         struct gnttab_copy *cop = queue->tx_copy_ops + *copy_ops;
 396         struct gnttab_map_grant_ref *gop = queue->tx_map_ops + *map_ops;
 397         struct xen_netif_tx_request *txp = first;
 398
 399         nr_slots = shinfo->nr_frags + frag_overflow + 1;
 400
 401         copy_count(skb) = 0;
 402         XENVIF_TX_CB(skb)->split_mask = 0;
 403
 404         /* Create copy ops for exactly data_len bytes into the skb head. */
 405         __skb_put(skb, data_len);
 406         while (data_len > 0) {
 407                 int amount = data_len > txp->size ? txp->size : data_len;
 408                 bool split = false;
 409
 410                 cop->source.u.ref = txp->gref;
 411                 cop->source.domid = queue->vif->domid;
 412                 cop->source.offset = txp->offset;
 413
 414                 cop->dest.domid = DOMID_SELF;
 415                 cop->dest.offset = (offset_in_page(skb->data +
 416                                                    skb_headlen(skb) -
 417                                                    data_len)) & ~XEN_PAGE_MASK;
 418                 cop->dest.u.gmfn = virt_to_gfn(skb->data + skb_headlen(skb)
 419                                                - data_len);
 420
 421                 /* Don't cross local page boundary! */
 422                 if (cop->dest.offset + amount > XEN_PAGE_SIZE) {
 423                         amount = XEN_PAGE_SIZE - cop->dest.offset;
 424                         XENVIF_TX_CB(skb)->split_mask |= 1U << copy_count(skb);
 425                         split = true;
 426                 }
 427
 428                 cop->len = amount;
 429                 cop->flags = GNTCOPY_source_gref;
 430
 431                 index = pending_index(queue->pending_cons);
 432                 pending_idx = queue->pending_ring[index];
 433                 callback_param(queue, pending_idx).ctx = NULL;
 434                 copy_pending_idx(skb, copy_count(skb)) = pending_idx;
 435                 if (!split)
 436                         copy_count(skb)++;
 437
 438                 cop++;
 439                 data_len -= amount;
 440
 441                 if (amount == txp->size) {
 442                         /* The copy op covered the full tx_request */
 443
 444                         memcpy(&queue->pending_tx_info[pending_idx].req,
 445                                txp, sizeof(*txp));
 446                         queue->pending_tx_info[pending_idx].extra_count =
 447                                 (txp == first) ? extra_count : 0;
 448
 449                         if (txp == first)
 450                                 txp = txfrags;
 451                         else
 452                                 txp++;
 453                         queue->pending_cons++;
 454                         nr_slots--;
 455                 } else {
 456                         /* The copy op partially covered the tx_request.
 457                          * The remainder will be mapped or copied in the next
 458                          * iteration.
 459                          */
 460                         txp->offset += amount;
 461                         txp->size -= amount;
 462                 }
 463         }
 464
 465         for (shinfo->nr_frags = 0; nr_slots > 0 && shinfo->nr_frags < MAX_SKB_FRAGS;
 466              shinfo->nr_frags++, gop++, nr_slots--) {
 467                 index = pending_index(queue->pending_cons++);
 468                 pending_idx = queue->pending_ring[index];
 469                 xenvif_tx_create_map_op(queue, pending_idx, txp,
 470                                         txp == first ? extra_count : 0, gop);
 471                 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
 472
 473                 if (txp == first)
 474                         txp = txfrags;
 475                 else
 476                         txp++;
 477         }
 478
 479         if (nr_slots > 0) {
 480
 481                 shinfo = skb_shinfo(nskb);
 482                 frags = shinfo->frags;
 483
 484                 for (shinfo->nr_frags = 0; shinfo->nr_frags < nr_slots;
 485                      shinfo->nr_frags++, txp++, gop++) {
 486                         index = pending_index(queue->pending_cons++);
 487                         pending_idx = queue->pending_ring[index];
 488                         xenvif_tx_create_map_op(queue, pending_idx, txp, 0,
 489                                                 gop);
 490                         frag_set_pending_idx(&frags[shinfo->nr_frags],
 491                                              pending_idx);
 492                 }
 493
 494                 skb_shinfo(skb)->frag_list = nskb;
 495         } else if (nskb) {
 496                 /* A frag_list skb was allocated but it is no longer needed
 497                  * because enough slots were converted to copy ops above.
 498                  */
 499                 kfree_skb(nskb);
 500         }
 501
 502         (*copy_ops) = cop - queue->tx_copy_ops;
 503         (*map_ops) = gop - queue->tx_map_ops;
 504 }
 505
 506 static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
 507                                            u16 pending_idx,
 508                                            grant_handle_t handle)
 509 {
 510         if (unlikely(queue->grant_tx_handle[pending_idx] !=
 511                      NETBACK_INVALID_HANDLE)) {
 512                 netdev_err(queue->vif->dev,
 513                            "Trying to overwrite active handle! pending_idx: 0x%x\n",
 514                            pending_idx);
 515                 BUG();
 516         }
 517         queue->grant_tx_handle[pending_idx] = handle;
 518 }
 519
 520 static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
 521                                              u16 pending_idx)
 522 {
 523         if (unlikely(queue->grant_tx_handle[pending_idx] ==
 524                      NETBACK_INVALID_HANDLE)) {
 525                 netdev_err(queue->vif->dev,
 526                            "Trying to unmap invalid handle! pending_idx: 0x%x\n",
 527                            pending_idx);
 528                 BUG();
 529         }
 530         queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
 531 }
 532
 533 static int xenvif_tx_check_gop(struct xenvif_queue *queue,
 534                                struct sk_buff *skb,
 535                                struct gnttab_map_grant_ref **gopp_map,
 536                                struct gnttab_copy **gopp_copy)
 537 {
 538         struct gnttab_map_grant_ref *gop_map = *gopp_map;
 539         u16 pending_idx;
 540         /* This always points to the shinfo of the skb being checked, which
 541          * could be either the first or the one on the frag_list
 542          */
 543         struct skb_shared_info *shinfo = skb_shinfo(skb);
 544         /* If this is non-NULL, we are currently checking the frag_list skb, and
 545          * this points to the shinfo of the first one
 546          */
 547         struct skb_shared_info *first_shinfo = NULL;
 548         int nr_frags = shinfo->nr_frags;
 549         const bool sharedslot = nr_frags &&
 550                                 frag_get_pending_idx(&shinfo->frags[0]) ==
 551                                     copy_pending_idx(skb, copy_count(skb) - 1);
 552         int i, err = 0;
 553
 554         for (i = 0; i < copy_count(skb); i++) {
 555                 int newerr;
 556
 557                 /* Check status of header. */
 558                 pending_idx = copy_pending_idx(skb, i);
 559
 560                 newerr = (*gopp_copy)->status;
 561
 562                 /* Split copies need to be handled together. */
 563                 if (XENVIF_TX_CB(skb)->split_mask & (1U << i)) {
 564                         (*gopp_copy)++;
 565                         if (!newerr)
 566                                 newerr = (*gopp_copy)->status;
 567                 }
 568                 if (likely(!newerr)) {
 569                         /* The first frag might still have this slot mapped */
 570                         if (i < copy_count(skb) - 1 || !sharedslot)
 571                                 xenvif_idx_release(queue, pending_idx,
 572                                                    XEN_NETIF_RSP_OKAY);
 573                 } else {
 574                         err = newerr;
 575                         if (net_ratelimit())
 576                                 netdev_dbg(queue->vif->dev,
 577                                            "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
 578                                            (*gopp_copy)->status,
 579                                            pending_idx,
 580                                            (*gopp_copy)->source.u.ref);
 581                         /* The first frag might still have this slot mapped */
 582                         if (i < copy_count(skb) - 1 || !sharedslot)
 583                                 xenvif_idx_release(queue, pending_idx,
 584                                                    XEN_NETIF_RSP_ERROR);
 585                 }
 586                 (*gopp_copy)++;
 587         }
 588
 589 check_frags:
 590         for (i = 0; i < nr_frags; i++, gop_map++) {
 591                 int j, newerr;
 592
 593                 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
 594
 595                 /* Check error status: if okay then remember grant handle. */
 596                 newerr = gop_map->status;
 597
 598                 if (likely(!newerr)) {
 599                         xenvif_grant_handle_set(queue,
 600                                                 pending_idx,
 601                                                 gop_map->handle);
 602                         /* Had a previous error? Invalidate this fragment. */
 603                         if (unlikely(err)) {
 604                                 xenvif_idx_unmap(queue, pending_idx);
 605                                 /* If the mapping of the first frag was OK, but
 606                                  * the header's copy failed, and they are
 607                                  * sharing a slot, send an error
 608                                  */
 609                                 if (i == 0 && !first_shinfo && sharedslot)
 610                                         xenvif_idx_release(queue, pending_idx,
 611                                                            XEN_NETIF_RSP_ERROR);
 612                                 else
 613                                         xenvif_idx_release(queue, pending_idx,
 614                                                            XEN_NETIF_RSP_OKAY);
 615                         }
 616                         continue;
 617                 }
 618
 619                 /* Error on this fragment: respond to client with an error. */
 620                 if (net_ratelimit())
 621                         netdev_dbg(queue->vif->dev,
 622                                    "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
 623                                    i,
 624                                    gop_map->status,
 625                                    pending_idx,
 626                                    gop_map->ref);
 627
 628                 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
 629
 630                 /* Not the first error? Preceding frags already invalidated. */
 631                 if (err)
 632                         continue;
 633
 634                 /* Invalidate preceding fragments of this skb. */
 635                 for (j = 0; j < i; j++) {
 636                         pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
 637                         xenvif_idx_unmap(queue, pending_idx);
 638                         xenvif_idx_release(queue, pending_idx,
 639                                            XEN_NETIF_RSP_OKAY);
 640                 }
 641
 642                 /* And if we found the error while checking the frag_list, unmap
 643                  * the first skb's frags
 644                  */
 645                 if (first_shinfo) {
 646                         for (j = 0; j < first_shinfo->nr_frags; j++) {
 647                                 pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
 648                                 xenvif_idx_unmap(queue, pending_idx);
 649                                 xenvif_idx_release(queue, pending_idx,
 650                                                    XEN_NETIF_RSP_OKAY);
 651                         }
 652                 }
 653
 654                 /* Remember the error: invalidate all subsequent fragments. */
 655                 err = newerr;
 656         }
 657
 658         if (skb_has_frag_list(skb) && !first_shinfo) {
 659                 first_shinfo = shinfo;
 660                 shinfo = skb_shinfo(shinfo->frag_list);
 661                 nr_frags = shinfo->nr_frags;
 662
 663                 goto check_frags;
 664         }
 665
 666         *gopp_map = gop_map;
 667         return err;
 668 }
 669
 670 static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
 671 {
 672         struct skb_shared_info *shinfo = skb_shinfo(skb);
 673         int nr_frags = shinfo->nr_frags;
 674         int i;
 675         u16 prev_pending_idx = INVALID_PENDING_IDX;
 676
 677         for (i = 0; i < nr_frags; i++) {
 678                 skb_frag_t *frag = shinfo->frags + i;
 679                 struct xen_netif_tx_request *txp;
 680                 struct page *page;
 681                 u16 pending_idx;
 682
 683                 pending_idx = frag_get_pending_idx(frag);
 684
 685                 /* If this is not the first frag, chain it to the previous*/
 686                 if (prev_pending_idx == INVALID_PENDING_IDX)
 687                         skb_shinfo(skb)->destructor_arg =
 688                                 &callback_param(queue, pending_idx);
 689                 else
 690                         callback_param(queue, prev_pending_idx).ctx =
 691                                 &callback_param(queue, pending_idx);
 692
 693                 callback_param(queue, pending_idx).ctx = NULL;
 694                 prev_pending_idx = pending_idx;
 695
 696                 txp = &queue->pending_tx_info[pending_idx].req;
 697                 page = virt_to_page((void *)idx_to_kaddr(queue, pending_idx));
 698                 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
 699                 skb->len += txp->size;
 700                 skb->data_len += txp->size;
 701                 skb->truesize += txp->size;
 702
 703                 /* Take an extra reference to offset network stack's put_page */
 704                 get_page(queue->mmap_pages[pending_idx]);
 705         }
 706 }
 707
 708 static int xenvif_get_extras(struct xenvif_queue *queue,
 709                              struct xen_netif_extra_info *extras,
 710                              unsigned int *extra_count,
 711                              int work_to_do)
 712 {
 713         struct xen_netif_extra_info extra;
 714         RING_IDX cons = queue->tx.req_cons;
 715
 716         do {
 717                 if (unlikely(work_to_do-- <= 0)) {
 718                         netdev_err(queue->vif->dev, "Missing extra info\n");
 719                         xenvif_fatal_tx_err(queue->vif);
 720                         return -EBADR;
 721                 }
 722
 723                 RING_COPY_REQUEST(&queue->tx, cons, &extra);
 724
 725                 queue->tx.req_cons = ++cons;
 726                 (*extra_count)++;
 727
 728                 if (unlikely(!extra.type ||
 729                              extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 730                         netdev_err(queue->vif->dev,
 731                                    "Invalid extra type: %d\n", extra.type);
 732                         xenvif_fatal_tx_err(queue->vif);
 733                         return -EINVAL;
 734                 }
 735
 736                 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
 737         } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
 738
 739         return work_to_do;
 740 }
 741
 742 static int xenvif_set_skb_gso(struct xenvif *vif,
 743                               struct sk_buff *skb,
 744                               struct xen_netif_extra_info *gso)
 745 {
 746         if (!gso->u.gso.size) {
 747                 netdev_err(vif->dev, "GSO size must not be zero.\n");
 748                 xenvif_fatal_tx_err(vif);
 749                 return -EINVAL;
 750         }
 751
 752         switch (gso->u.gso.type) {
 753         case XEN_NETIF_GSO_TYPE_TCPV4:
 754                 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 755                 break;
 756         case XEN_NETIF_GSO_TYPE_TCPV6:
 757                 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 758                 break;
 759         default:
 760                 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
 761                 xenvif_fatal_tx_err(vif);
 762                 return -EINVAL;
 763         }
 764
 765         skb_shinfo(skb)->gso_size = gso->u.gso.size;
 766         /* gso_segs will be calculated later */
 767
 768         return 0;
 769 }
 770
 771 static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
 772 {
 773         bool recalculate_partial_csum = false;
 774
 775         /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 776          * peers can fail to set NETRXF_csum_blank when sending a GSO
 777          * frame. In this case force the SKB to CHECKSUM_PARTIAL and
 778          * recalculate the partial checksum.
 779          */
 780         if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
 781                 queue->stats.rx_gso_checksum_fixup++;
 782                 skb->ip_summed = CHECKSUM_PARTIAL;
 783                 recalculate_partial_csum = true;
 784         }
 785
 786         /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
 787         if (skb->ip_summed != CHECKSUM_PARTIAL)
 788                 return 0;
 789
 790         return skb_checksum_setup(skb, recalculate_partial_csum);
 791 }
 792
 793 static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
 794 {
 795         u64 now = get_jiffies_64();
 796         u64 next_credit = queue->credit_window_start +
 797                 msecs_to_jiffies(queue->credit_usec / 1000);
 798
 799         /* Timer could already be pending in rare cases. */
 800         if (timer_pending(&queue->credit_timeout)) {
 801                 queue->rate_limited = true;
 802                 return true;
 803         }
 804
 805         /* Passed the point where we can replenish credit? */
 806         if (time_after_eq64(now, next_credit)) {
 807                 queue->credit_window_start = now;
 808                 tx_add_credit(queue);
 809         }
 810
 811         /* Still too big to send right now? Set a callback. */
 812         if (size > queue->remaining_credit) {
 813                 mod_timer(&queue->credit_timeout,
 814                           next_credit);
 815                 queue->credit_window_start = next_credit;
 816                 queue->rate_limited = true;
 817
 818                 return true;
 819         }
 820
 821         return false;
 822 }
 823
 824 /* No locking is required in xenvif_mcast_add/del() as they are
 825  * only ever invoked from NAPI poll. An RCU list is used because
 826  * xenvif_mcast_match() is called asynchronously, during start_xmit.
 827  */
 828
 829 static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
 830 {
 831         struct xenvif_mcast_addr *mcast;
 832
 833         if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
 834                 if (net_ratelimit())
 835                         netdev_err(vif->dev,
 836                                    "Too many multicast addresses\n");
 837                 return -ENOSPC;
 838         }
 839
 840         mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
 841         if (!mcast)
 842                 return -ENOMEM;
 843
 844         ether_addr_copy(mcast->addr, addr);
 845         list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
 846         vif->fe_mcast_count++;
 847
 848         return 0;
 849 }
 850
 851 static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
 852 {
 853         struct xenvif_mcast_addr *mcast;
 854
 855         list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
 856                 if (ether_addr_equal(addr, mcast->addr)) {
 857                         --vif->fe_mcast_count;
 858                         list_del_rcu(&mcast->entry);
 859                         kfree_rcu(mcast, rcu);
 860                         break;
 861                 }
 862         }
 863 }
 864
 865 bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
 866 {
 867         struct xenvif_mcast_addr *mcast;
 868
 869         rcu_read_lock();
 870         list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
 871                 if (ether_addr_equal(addr, mcast->addr)) {
 872                         rcu_read_unlock();
 873                         return true;
 874                 }
 875         }
 876         rcu_read_unlock();
 877
 878         return false;
 879 }
 880
 881 void xenvif_mcast_addr_list_free(struct xenvif *vif)
 882 {
 883         /* No need for locking or RCU here. NAPI poll and TX queue
 884          * are stopped.
 885          */
 886         while (!list_empty(&vif->fe_mcast_addr)) {
 887                 struct xenvif_mcast_addr *mcast;
 888
 889                 mcast = list_first_entry(&vif->fe_mcast_addr,
 890                                          struct xenvif_mcast_addr,
 891                                          entry);
 892                 --vif->fe_mcast_count;
 893                 list_del(&mcast->entry);
 894                 kfree(mcast);
 895         }
 896 }
 897
 898 static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 899                                      int budget,
 900                                      unsigned *copy_ops,
 901                                      unsigned *map_ops)
 902 {
 903         struct sk_buff *skb, *nskb;
 904         int ret;
 905         unsigned int frag_overflow;
 906
 907         while (skb_queue_len(&queue->tx_queue) < budget) {
 908                 struct xen_netif_tx_request txreq;
 909                 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
 910                 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
 911                 unsigned int extra_count;
 912                 RING_IDX idx;
 913                 int work_to_do;
 914                 unsigned int data_len;
 915
 916                 if (queue->tx.sring->req_prod - queue->tx.req_cons >
 917                     XEN_NETIF_TX_RING_SIZE) {
 918                         netdev_err(queue->vif->dev,
 919                                    "Impossible number of requests. "
 920                                    "req_prod %d, req_cons %d, size %ld\n",
 921                                    queue->tx.sring->req_prod, queue->tx.req_cons,
 922                                    XEN_NETIF_TX_RING_SIZE);
 923                         xenvif_fatal_tx_err(queue->vif);
 924                         break;
 925                 }
 926
 927                 work_to_do = XEN_RING_NR_UNCONSUMED_REQUESTS(&queue->tx);
 928                 if (!work_to_do)
 929                         break;
 930
 931                 idx = queue->tx.req_cons;
 932                 rmb(); /* Ensure that we see the request before we copy it. */
 933                 RING_COPY_REQUEST(&queue->tx, idx, &txreq);
 934
 935                 /* Credit-based scheduling. */
 936                 if (txreq.size > queue->remaining_credit &&
 937                     tx_credit_exceeded(queue, txreq.size))
 938                         break;
 939
 940                 queue->remaining_credit -= txreq.size;
 941
 942                 work_to_do--;
 943                 queue->tx.req_cons = ++idx;
 944
 945                 memset(extras, 0, sizeof(extras));
 946                 extra_count = 0;
 947                 if (txreq.flags & XEN_NETTXF_extra_info) {
 948                         work_to_do = xenvif_get_extras(queue, extras,
 949                                                        &extra_count,
 950                                                        work_to_do);
 951                         idx = queue->tx.req_cons;
 952                         if (unlikely(work_to_do < 0))
 953                                 break;
 954                 }
 955
 956                 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
 957                         struct xen_netif_extra_info *extra;
 958
 959                         extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
 960                         ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
 961
 962                         make_tx_response(queue, &txreq, extra_count,
 963                                          (ret == 0) ?
 964                                          XEN_NETIF_RSP_OKAY :
 965                                          XEN_NETIF_RSP_ERROR);
 966                         push_tx_responses(queue);
 967                         continue;
 968                 }
 969
 970                 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
 971                         struct xen_netif_extra_info *extra;
 972
 973                         extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
 974                         xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
 975
 976                         make_tx_response(queue, &txreq, extra_count,
 977                                          XEN_NETIF_RSP_OKAY);
 978                         push_tx_responses(queue);
 979                         continue;
 980                 }
 981
 982                 data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN) ?
 983                         XEN_NETBACK_TX_COPY_LEN : txreq.size;
 984
 985                 ret = xenvif_count_requests(queue, &txreq, extra_count,
 986                                             txfrags, work_to_do);
 987
 988                 if (unlikely(ret < 0))
 989                         break;
 990
 991                 idx += ret;
 992
 993                 if (unlikely(txreq.size < ETH_HLEN)) {
 994                         netdev_dbg(queue->vif->dev,
 995                                    "Bad packet size: %d\n", txreq.size);
 996                         xenvif_tx_err(queue, &txreq, extra_count, idx);
 997                         break;
 998                 }
 999
1000                 /* No crossing a page as the payload mustn't fragment. */
1001                 if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
1002                         netdev_err(queue->vif->dev, "Cross page boundary, txreq.offset: %u, size: %u\n",
1003                                    txreq.offset, txreq.size);
1004                         xenvif_fatal_tx_err(queue->vif);
1005                         break;
1006                 }
1007
1008                 if (ret >= XEN_NETBK_LEGACY_SLOTS_MAX - 1 && data_len < txreq.size)
1009                         data_len = txreq.size;
1010
1011                 skb = xenvif_alloc_skb(data_len);
1012                 if (unlikely(skb == NULL)) {
1013                         netdev_dbg(queue->vif->dev,
1014                                    "Can't allocate a skb in start_xmit.\n");
1015                         xenvif_tx_err(queue, &txreq, extra_count, idx);
1016                         break;
1017                 }
1018
1019                 skb_shinfo(skb)->nr_frags = ret;
1020                 /* At this point shinfo->nr_frags is in fact the number of
1021                  * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
1022                  */
1023                 frag_overflow = 0;
1024                 nskb = NULL;
1025                 if (skb_shinfo(skb)->nr_frags > MAX_SKB_FRAGS) {
1026                         frag_overflow = skb_shinfo(skb)->nr_frags - MAX_SKB_FRAGS;
1027                         BUG_ON(frag_overflow > MAX_SKB_FRAGS);
1028                         skb_shinfo(skb)->nr_frags = MAX_SKB_FRAGS;
1029                         nskb = xenvif_alloc_skb(0);
1030                         if (unlikely(nskb == NULL)) {
1031                                 skb_shinfo(skb)->nr_frags = 0;
1032                                 kfree_skb(skb);
1033                                 xenvif_tx_err(queue, &txreq, extra_count, idx);
1034                                 if (net_ratelimit())
1035                                         netdev_err(queue->vif->dev,
1036                                                    "Can't allocate the frag_list skb.\n");
1037                                 break;
1038                         }
1039                 }
1040
1041                 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1042                         struct xen_netif_extra_info *gso;
1043                         gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1044
1045                         if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
1046                                 /* Failure in xenvif_set_skb_gso is fatal. */
1047                                 skb_shinfo(skb)->nr_frags = 0;
1048                                 kfree_skb(skb);
1049                                 kfree_skb(nskb);
1050                                 break;
1051                         }
1052                 }
1053
1054                 if (extras[XEN_NETIF_EXTRA_TYPE_HASH - 1].type) {
1055                         struct xen_netif_extra_info *extra;
1056                         enum pkt_hash_types type = PKT_HASH_TYPE_NONE;
1057
1058                         extra = &extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
1059
1060                         switch (extra->u.hash.type) {
1061                         case _XEN_NETIF_CTRL_HASH_TYPE_IPV4:
1062                         case _XEN_NETIF_CTRL_HASH_TYPE_IPV6:
1063                                 type = PKT_HASH_TYPE_L3;
1064                                 break;
1065
1066                         case _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP:
1067                         case _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP:
1068                                 type = PKT_HASH_TYPE_L4;
1069                                 break;
1070
1071                         default:
1072                                 break;
1073                         }
1074
1075                         if (type != PKT_HASH_TYPE_NONE)
1076                                 skb_set_hash(skb,
1077                                              *(u32 *)extra->u.hash.value,
1078                                              type);
1079                 }
1080
1081                 xenvif_get_requests(queue, skb, &txreq, txfrags, copy_ops,
1082                                     map_ops, frag_overflow, nskb, extra_count,
1083                                     data_len);
1084
1085                 __skb_queue_tail(&queue->tx_queue, skb);
1086
1087                 queue->tx.req_cons = idx;
1088         }
1089
1090         return;
1091 }
1092
1093 /* Consolidate skb with a frag_list into a brand new one with local pages on
1094  * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1095  */
1096 static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1097 {
1098         unsigned int offset = skb_headlen(skb);
1099         skb_frag_t frags[MAX_SKB_FRAGS];
1100         int i, f;
1101         struct ubuf_info *uarg;
1102         struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1103
1104         queue->stats.tx_zerocopy_sent += 2;
1105         queue->stats.tx_frag_overflow++;
1106
1107         xenvif_fill_frags(queue, nskb);
1108         /* Subtract frags size, we will correct it later */
1109         skb->truesize -= skb->data_len;
1110         skb->len += nskb->len;
1111         skb->data_len += nskb->len;
1112
1113         /* create a brand new frags array and coalesce there */
1114         for (i = 0; offset < skb->len; i++) {
1115                 struct page *page;
1116                 unsigned int len;
1117
1118                 BUG_ON(i >= MAX_SKB_FRAGS);
1119                 page = alloc_page(GFP_ATOMIC);
1120                 if (!page) {
1121                         int j;
1122                         skb->truesize += skb->data_len;
1123                         for (j = 0; j < i; j++)
1124                                 put_page(skb_frag_page(&frags[j]));
1125                         return -ENOMEM;
1126                 }
1127
1128                 if (offset + PAGE_SIZE < skb->len)
1129                         len = PAGE_SIZE;
1130                 else
1131                         len = skb->len - offset;
1132                 if (skb_copy_bits(skb, offset, page_address(page), len))
1133                         BUG();
1134
1135                 offset += len;
1136                 skb_frag_fill_page_desc(&frags[i], page, 0, len);
1137         }
1138
1139         /* Release all the original (foreign) frags. */
1140         for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
1141                 skb_frag_unref(skb, f);
1142         uarg = skb_shinfo(skb)->destructor_arg;
1143         /* increase inflight counter to offset decrement in callback */
1144         atomic_inc(&queue->inflight_packets);
1145         uarg->callback(NULL, uarg, true);
1146         skb_shinfo(skb)->destructor_arg = NULL;
1147
1148         /* Fill the skb with the new (local) frags. */
1149         memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
1150         skb_shinfo(skb)->nr_frags = i;
1151         skb->truesize += i * PAGE_SIZE;
1152
1153         return 0;
1154 }
1155
1156 static int xenvif_tx_submit(struct xenvif_queue *queue)
1157 {
1158         struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1159         struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1160         struct sk_buff *skb;
1161         int work_done = 0;
1162
1163         while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1164                 struct xen_netif_tx_request *txp;
1165                 u16 pending_idx;
1166
1167                 pending_idx = copy_pending_idx(skb, 0);
1168                 txp = &queue->pending_tx_info[pending_idx].req;
1169
1170                 /* Check the remap error code. */
1171                 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1172                         /* If there was an error, xenvif_tx_check_gop is
1173                          * expected to release all the frags which were mapped,
1174                          * so kfree_skb shouldn't do it again
1175                          */
1176                         skb_shinfo(skb)->nr_frags = 0;
1177                         if (skb_has_frag_list(skb)) {
1178                                 struct sk_buff *nskb =
1179                                                 skb_shinfo(skb)->frag_list;
1180                                 skb_shinfo(nskb)->nr_frags = 0;
1181                         }
1182                         kfree_skb(skb);
1183                         continue;
1184                 }
1185
1186                 if (txp->flags & XEN_NETTXF_csum_blank)
1187                         skb->ip_summed = CHECKSUM_PARTIAL;
1188                 else if (txp->flags & XEN_NETTXF_data_validated)
1189                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1190
1191                 xenvif_fill_frags(queue, skb);
1192
1193                 if (unlikely(skb_has_frag_list(skb))) {
1194                         struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1195                         xenvif_skb_zerocopy_prepare(queue, nskb);
1196                         if (xenvif_handle_frag_list(queue, skb)) {
1197                                 if (net_ratelimit())
1198                                         netdev_err(queue->vif->dev,
1199                                                    "Not enough memory to consolidate frag_list!\n");
1200                                 xenvif_skb_zerocopy_prepare(queue, skb);
1201                                 kfree_skb(skb);
1202                                 continue;
1203                         }
1204                         /* Copied all the bits from the frag list -- free it. */
1205                         skb_frag_list_init(skb);
1206                         kfree_skb(nskb);
1207                 }
1208
1209                 skb->dev      = queue->vif->dev;
1210                 skb->protocol = eth_type_trans(skb, skb->dev);
1211                 skb_reset_network_header(skb);
1212
1213                 if (checksum_setup(queue, skb)) {
1214                         netdev_dbg(queue->vif->dev,
1215                                    "Can't setup checksum in net_tx_action\n");
1216                         /* We have to set this flag to trigger the callback */
1217                         if (skb_shinfo(skb)->destructor_arg)
1218                                 xenvif_skb_zerocopy_prepare(queue, skb);
1219                         kfree_skb(skb);
1220                         continue;
1221                 }
1222
1223                 skb_probe_transport_header(skb);
1224
1225                 /* If the packet is GSO then we will have just set up the
1226                  * transport header offset in checksum_setup so it's now
1227                  * straightforward to calculate gso_segs.
1228                  */
1229                 if (skb_is_gso(skb)) {
1230                         int mss, hdrlen;
1231
1232                         /* GSO implies having the L4 header. */
1233                         WARN_ON_ONCE(!skb_transport_header_was_set(skb));
1234                         if (unlikely(!skb_transport_header_was_set(skb))) {
1235                                 kfree_skb(skb);
1236                                 continue;
1237                         }
1238
1239                         mss = skb_shinfo(skb)->gso_size;
1240                         hdrlen = skb_tcp_all_headers(skb);
1241
1242                         skb_shinfo(skb)->gso_segs =
1243                                 DIV_ROUND_UP(skb->len - hdrlen, mss);
1244                 }
1245
1246                 queue->stats.rx_bytes += skb->len;
1247                 queue->stats.rx_packets++;
1248
1249                 work_done++;
1250
1251                 /* Set this flag right before netif_receive_skb, otherwise
1252                  * someone might think this packet already left netback, and
1253                  * do a skb_copy_ubufs while we are still in control of the
1254                  * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1255                  */
1256                 if (skb_shinfo(skb)->destructor_arg) {
1257                         xenvif_skb_zerocopy_prepare(queue, skb);
1258                         queue->stats.tx_zerocopy_sent++;
1259                 }
1260
1261                 netif_receive_skb(skb);
1262         }
1263
1264         return work_done;
1265 }
1266
1267 void xenvif_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *ubuf_base,
1268                               bool zerocopy_success)
1269 {
1270         unsigned long flags;
1271         pending_ring_idx_t index;
1272         struct ubuf_info_msgzc *ubuf = uarg_to_msgzc(ubuf_base);
1273         struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1274
1275         /* This is the only place where we grab this lock, to protect callbacks
1276          * from each other.
1277          */
1278         spin_lock_irqsave(&queue->callback_lock, flags);
1279         do {
1280                 u16 pending_idx = ubuf->desc;
1281                 ubuf = (struct ubuf_info_msgzc *) ubuf->ctx;
1282                 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1283                         MAX_PENDING_REQS);
1284                 index = pending_index(queue->dealloc_prod);
1285                 queue->dealloc_ring[index] = pending_idx;
1286                 /* Sync with xenvif_tx_dealloc_action:
1287                  * insert idx then incr producer.
1288                  */
1289                 smp_wmb();
1290                 queue->dealloc_prod++;
1291         } while (ubuf);
1292         spin_unlock_irqrestore(&queue->callback_lock, flags);
1293
1294         if (likely(zerocopy_success))
1295                 queue->stats.tx_zerocopy_success++;
1296         else
1297                 queue->stats.tx_zerocopy_fail++;
1298         xenvif_skb_zerocopy_complete(queue);
1299 }
1300
1301 static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1302 {
1303         struct gnttab_unmap_grant_ref *gop;
1304         pending_ring_idx_t dc, dp;
1305         u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1306         unsigned int i = 0;
1307
1308         dc = queue->dealloc_cons;
1309         gop = queue->tx_unmap_ops;
1310
1311         /* Free up any grants we have finished using */
1312         do {
1313                 dp = queue->dealloc_prod;
1314
1315                 /* Ensure we see all indices enqueued by all
1316                  * xenvif_zerocopy_callback().
1317                  */
1318                 smp_rmb();
1319
1320                 while (dc != dp) {
1321                         BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS);
1322                         pending_idx =
1323                                 queue->dealloc_ring[pending_index(dc++)];
1324
1325                         pending_idx_release[gop - queue->tx_unmap_ops] =
1326                                 pending_idx;
1327                         queue->pages_to_unmap[gop - queue->tx_unmap_ops] =
1328                                 queue->mmap_pages[pending_idx];
1329                         gnttab_set_unmap_op(gop,
1330                                             idx_to_kaddr(queue, pending_idx),
1331                                             GNTMAP_host_map,
1332                                             queue->grant_tx_handle[pending_idx]);
1333                         xenvif_grant_handle_reset(queue, pending_idx);
1334                         ++gop;
1335                 }
1336
1337         } while (dp != queue->dealloc_prod);
1338
1339         queue->dealloc_cons = dc;
1340
1341         if (gop - queue->tx_unmap_ops > 0) {
1342                 int ret;
1343                 ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1344                                         NULL,
1345                                         queue->pages_to_unmap,
1346                                         gop - queue->tx_unmap_ops);
1347                 if (ret) {
1348                         netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tu ret %d\n",
1349                                    gop - queue->tx_unmap_ops, ret);
1350                         for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1351                                 if (gop[i].status != GNTST_okay)
1352                                         netdev_err(queue->vif->dev,
1353                                                    " host_addr: 0x%llx handle: 0x%x status: %d\n",
1354                                                    gop[i].host_addr,
1355                                                    gop[i].handle,
1356                                                    gop[i].status);
1357                         }
1358                         BUG();
1359                 }
1360         }
1361
1362         for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1363                 xenvif_idx_release(queue, pending_idx_release[i],
1364                                    XEN_NETIF_RSP_OKAY);
1365 }
1366
1367
1368 /* Called after netfront has transmitted */
1369 int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1370 {
1371         unsigned nr_mops = 0, nr_cops = 0;
1372         int work_done, ret;
1373
1374         if (unlikely(!tx_work_todo(queue)))
1375                 return 0;
1376
1377         xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1378
1379         if (nr_cops == 0)
1380                 return 0;
1381
1382         gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1383         if (nr_mops != 0) {
1384                 ret = gnttab_map_refs(queue->tx_map_ops,
1385                                       NULL,
1386                                       queue->pages_to_map,
1387                                       nr_mops);
1388                 if (ret) {
1389                         unsigned int i;
1390
1391                         netdev_err(queue->vif->dev, "Map fail: nr %u ret %d\n",
1392                                    nr_mops, ret);
1393                         for (i = 0; i < nr_mops; ++i)
1394                                 WARN_ON_ONCE(queue->tx_map_ops[i].status ==
1395                                              GNTST_okay);
1396                 }
1397         }
1398
1399         work_done = xenvif_tx_submit(queue);
1400
1401         return work_done;
1402 }
1403
1404 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1405                                u8 status)
1406 {
1407         struct pending_tx_info *pending_tx_info;
1408         pending_ring_idx_t index;
1409         unsigned long flags;
1410
1411         pending_tx_info = &queue->pending_tx_info[pending_idx];
1412
1413         spin_lock_irqsave(&queue->response_lock, flags);
1414
1415         make_tx_response(queue, &pending_tx_info->req,
1416                          pending_tx_info->extra_count, status);
1417
1418         /* Release the pending index before pusing the Tx response so
1419          * its available before a new Tx request is pushed by the
1420          * frontend.
1421          */
1422         index = pending_index(queue->pending_prod++);
1423         queue->pending_ring[index] = pending_idx;
1424
1425         push_tx_responses(queue);
1426
1427         spin_unlock_irqrestore(&queue->response_lock, flags);
1428 }
1429
1430
1431 static void make_tx_response(struct xenvif_queue *queue,
1432                              struct xen_netif_tx_request *txp,
1433                              unsigned int extra_count,
1434                              s8       st)
1435 {
1436         RING_IDX i = queue->tx.rsp_prod_pvt;
1437         struct xen_netif_tx_response *resp;
1438
1439         resp = RING_GET_RESPONSE(&queue->tx, i);
1440         resp->id     = txp->id;
1441         resp->status = st;
1442
1443         while (extra_count-- != 0)
1444                 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1445
1446         queue->tx.rsp_prod_pvt = ++i;
1447 }
1448
1449 static void push_tx_responses(struct xenvif_queue *queue)
1450 {
1451         int notify;
1452
1453         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1454         if (notify)
1455                 notify_remote_via_irq(queue->tx_irq);
1456 }
1457
1458 static void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1459 {
1460         int ret;
1461         struct gnttab_unmap_grant_ref tx_unmap_op;
1462
1463         gnttab_set_unmap_op(&tx_unmap_op,
1464                             idx_to_kaddr(queue, pending_idx),
1465                             GNTMAP_host_map,
1466                             queue->grant_tx_handle[pending_idx]);
1467         xenvif_grant_handle_reset(queue, pending_idx);
1468
1469         ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1470                                 &queue->mmap_pages[pending_idx], 1);
1471         if (ret) {
1472                 netdev_err(queue->vif->dev,
1473                            "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: 0x%x status: %d\n",
1474                            ret,
1475                            pending_idx,
1476                            tx_unmap_op.host_addr,
1477                            tx_unmap_op.handle,
1478                            tx_unmap_op.status);
1479                 BUG();
1480         }
1481 }
1482
1483 static inline int tx_work_todo(struct xenvif_queue *queue)
1484 {
1485         if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1486                 return 1;
1487
1488         return 0;
1489 }
1490
1491 static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1492 {
1493         return queue->dealloc_cons != queue->dealloc_prod;
1494 }
1495
1496 void xenvif_unmap_frontend_data_rings(struct xenvif_queue *queue)
1497 {
1498         if (queue->tx.sring)
1499                 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1500                                         queue->tx.sring);
1501         if (queue->rx.sring)
1502                 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1503                                         queue->rx.sring);
1504 }
1505
1506 int xenvif_map_frontend_data_rings(struct xenvif_queue *queue,
1507                                    grant_ref_t tx_ring_ref,
1508                                    grant_ref_t rx_ring_ref)
1509 {
1510         void *addr;
1511         struct xen_netif_tx_sring *txs;
1512         struct xen_netif_rx_sring *rxs;
1513         RING_IDX rsp_prod, req_prod;
1514         int err;
1515
1516         err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1517                                      &tx_ring_ref, 1, &addr);
1518         if (err)
1519                 goto err;
1520
1521         txs = (struct xen_netif_tx_sring *)addr;
1522         rsp_prod = READ_ONCE(txs->rsp_prod);
1523         req_prod = READ_ONCE(txs->req_prod);
1524
1525         BACK_RING_ATTACH(&queue->tx, txs, rsp_prod, XEN_PAGE_SIZE);
1526
1527         err = -EIO;
1528         if (req_prod - rsp_prod > RING_SIZE(&queue->tx))
1529                 goto err;
1530
1531         err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1532                                      &rx_ring_ref, 1, &addr);
1533         if (err)
1534                 goto err;
1535
1536         rxs = (struct xen_netif_rx_sring *)addr;
1537         rsp_prod = READ_ONCE(rxs->rsp_prod);
1538         req_prod = READ_ONCE(rxs->req_prod);
1539
1540         BACK_RING_ATTACH(&queue->rx, rxs, rsp_prod, XEN_PAGE_SIZE);
1541
1542         err = -EIO;
1543         if (req_prod - rsp_prod > RING_SIZE(&queue->rx))
1544                 goto err;
1545
1546         return 0;
1547
1548 err:
1549         xenvif_unmap_frontend_data_rings(queue);
1550         return err;
1551 }
1552
1553 static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
1554 {
1555         /* Dealloc thread must remain running until all inflight
1556          * packets complete.
1557          */
1558         return kthread_should_stop() &&
1559                 !atomic_read(&queue->inflight_packets);
1560 }
1561
1562 int xenvif_dealloc_kthread(void *data)
1563 {
1564         struct xenvif_queue *queue = data;
1565
1566         for (;;) {
1567                 wait_event_interruptible(queue->dealloc_wq,
1568                                          tx_dealloc_work_todo(queue) ||
1569                                          xenvif_dealloc_kthread_should_stop(queue));
1570                 if (xenvif_dealloc_kthread_should_stop(queue))
1571                         break;
1572
1573                 xenvif_tx_dealloc_action(queue);
1574                 cond_resched();
1575         }
1576
1577         /* Unmap anything remaining*/
1578         if (tx_dealloc_work_todo(queue))
1579                 xenvif_tx_dealloc_action(queue);
1580
1581         return 0;
1582 }
1583
1584 static void make_ctrl_response(struct xenvif *vif,
1585                                const struct xen_netif_ctrl_request *req,
1586                                u32 status, u32 data)
1587 {
1588         RING_IDX idx = vif->ctrl.rsp_prod_pvt;
1589         struct xen_netif_ctrl_response rsp = {
1590                 .id = req->id,
1591                 .type = req->type,
1592                 .status = status,
1593                 .data = data,
1594         };
1595
1596         *RING_GET_RESPONSE(&vif->ctrl, idx) = rsp;
1597         vif->ctrl.rsp_prod_pvt = ++idx;
1598 }
1599
1600 static void push_ctrl_response(struct xenvif *vif)
1601 {
1602         int notify;
1603
1604         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->ctrl, notify);
1605         if (notify)
1606                 notify_remote_via_irq(vif->ctrl_irq);
1607 }
1608
1609 static void process_ctrl_request(struct xenvif *vif,
1610                                  const struct xen_netif_ctrl_request *req)
1611 {
1612         u32 status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED;
1613         u32 data = 0;
1614
1615         switch (req->type) {
1616         case XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM:
1617                 status = xenvif_set_hash_alg(vif, req->data[0]);
1618                 break;
1619
1620         case XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS:
1621                 status = xenvif_get_hash_flags(vif, &data);
1622                 break;
1623
1624         case XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS:
1625                 status = xenvif_set_hash_flags(vif, req->data[0]);
1626                 break;
1627
1628         case XEN_NETIF_CTRL_TYPE_SET_HASH_KEY:
1629                 status = xenvif_set_hash_key(vif, req->data[0],
1630                                              req->data[1]);
1631                 break;
1632
1633         case XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE:
1634                 status = XEN_NETIF_CTRL_STATUS_SUCCESS;
1635                 data = XEN_NETBK_MAX_HASH_MAPPING_SIZE;
1636                 break;
1637
1638         case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE:
1639                 status = xenvif_set_hash_mapping_size(vif,
1640                                                       req->data[0]);
1641                 break;
1642
1643         case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING:
1644                 status = xenvif_set_hash_mapping(vif, req->data[0],
1645                                                  req->data[1],
1646                                                  req->data[2]);
1647                 break;
1648
1649         default:
1650                 break;
1651         }
1652
1653         make_ctrl_response(vif, req, status, data);
1654         push_ctrl_response(vif);
1655 }
1656
1657 static void xenvif_ctrl_action(struct xenvif *vif)
1658 {
1659         for (;;) {
1660                 RING_IDX req_prod, req_cons;
1661
1662                 req_prod = vif->ctrl.sring->req_prod;
1663                 req_cons = vif->ctrl.req_cons;
1664
1665                 /* Make sure we can see requests before we process them. */
1666                 rmb();
1667
1668                 if (req_cons == req_prod)
1669                         break;
1670
1671                 while (req_cons != req_prod) {
1672                         struct xen_netif_ctrl_request req;
1673
1674                         RING_COPY_REQUEST(&vif->ctrl, req_cons, &req);
1675                         req_cons++;
1676
1677                         process_ctrl_request(vif, &req);
1678                 }
1679
1680                 vif->ctrl.req_cons = req_cons;
1681                 vif->ctrl.sring->req_event = req_cons + 1;
1682         }
1683 }
1684
1685 static bool xenvif_ctrl_work_todo(struct xenvif *vif)
1686 {
1687         if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->ctrl)))
1688                 return true;
1689
1690         return false;
1691 }
1692
1693 irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data)
1694 {
1695         struct xenvif *vif = data;
1696         unsigned int eoi_flag = XEN_EOI_FLAG_SPURIOUS;
1697
1698         while (xenvif_ctrl_work_todo(vif)) {
1699                 xenvif_ctrl_action(vif);
1700                 eoi_flag = 0;
1701         }
1702
1703         xen_irq_lateeoi(irq, eoi_flag);
1704
1705         return IRQ_HANDLED;
1706 }
1707
1708 static int __init netback_init(void)
1709 {
1710         int rc = 0;
1711
1712         if (!xen_domain())
1713                 return -ENODEV;
1714
1715         /* Allow as many queues as there are CPUs but max. 8 if user has not
1716          * specified a value.
1717          */
1718         if (xenvif_max_queues == 0)
1719                 xenvif_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
1720                                           num_online_cpus());
1721
1722         if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1723                 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1724                         fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1725                 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1726         }
1727
1728         rc = xenvif_xenbus_init();
1729         if (rc)
1730                 goto failed_init;
1731
1732 #ifdef CONFIG_DEBUG_FS
1733         xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
1734 #endif /* CONFIG_DEBUG_FS */
1735
1736         return 0;
1737
1738 failed_init:
1739         return rc;
1740 }
1741
1742 module_init(netback_init);
1743
1744 static void __exit netback_fini(void)
1745 {
1746 #ifdef CONFIG_DEBUG_FS
1747         debugfs_remove_recursive(xen_netback_dbg_root);
1748 #endif /* CONFIG_DEBUG_FS */
1749         xenvif_xenbus_fini();
1750 }
1751 module_exit(netback_fini);
1752
1753 MODULE_LICENSE("Dual BSD/GPL");
1754 MODULE_ALIAS("xen-backend:vif");