linux/drivers/net/xen-netback/netback.c
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   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 */
  55bool separate_tx_rx_irq = true;
  56module_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 */
  61unsigned int rx_drain_timeout_msecs = 10000;
  62module_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 */
  67unsigned int rx_stall_timeout_msecs = 60000;
  68module_param(rx_stall_timeout_msecs, uint, 0444);
  69
  70#define MAX_QUEUES_DEFAULT 8
  71unsigned int xenvif_max_queues;
  72module_param_named(max_queues, xenvif_max_queues, uint, 0644);
  73MODULE_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
  81static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
  82module_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
  95unsigned int xenvif_hash_cache_size = XENVIF_HASH_CACHE_SIZE_DEFAULT;
  96module_param_named(hash_cache_size, xenvif_hash_cache_size, uint, 0644);
  97MODULE_PARM_DESC(hash_cache_size, "Number of flows in the hash cache");
  98
  99static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
 100                               u8 status);
 101
 102static void make_tx_response(struct xenvif_queue *queue,
 103                             struct xen_netif_tx_request *txp,
 104                             unsigned int extra_count,
 105                             s8       st);
 106static void push_tx_responses(struct xenvif_queue *queue);
 107
 108static inline int tx_work_todo(struct xenvif_queue *queue);
 109
 110static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
 111                                       u16 idx)
 112{
 113        return page_to_pfn(queue->mmap_pages[idx]);
 114}
 115
 116static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
 117                                         u16 idx)
 118{
 119        return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
 120}
 121
 122#define callback_param(vif, pending_idx) \
 123        (vif->pending_tx_info[pending_idx].callback_struct)
 124
 125/* Find the containing VIF's structure from a pointer in pending_tx_info array
 126 */
 127static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
 128{
 129        u16 pending_idx = ubuf->desc;
 130        struct pending_tx_info *temp =
 131                container_of(ubuf, struct pending_tx_info, callback_struct);
 132        return container_of(temp - pending_idx,
 133                            struct xenvif_queue,
 134                            pending_tx_info[0]);
 135}
 136
 137static u16 frag_get_pending_idx(skb_frag_t *frag)
 138{
 139        return (u16)frag->page_offset;
 140}
 141
 142static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
 143{
 144        frag->page_offset = pending_idx;
 145}
 146
 147static inline pending_ring_idx_t pending_index(unsigned i)
 148{
 149        return i & (MAX_PENDING_REQS-1);
 150}
 151
 152void xenvif_kick_thread(struct xenvif_queue *queue)
 153{
 154        wake_up(&queue->wq);
 155}
 156
 157void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
 158{
 159        int more_to_do;
 160
 161        RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
 162
 163        if (more_to_do)
 164                napi_schedule(&queue->napi);
 165}
 166
 167static void tx_add_credit(struct xenvif_queue *queue)
 168{
 169        unsigned long max_burst, max_credit;
 170
 171        /*
 172         * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
 173         * Otherwise the interface can seize up due to insufficient credit.
 174         */
 175        max_burst = max(131072UL, queue->credit_bytes);
 176
 177        /* Take care that adding a new chunk of credit doesn't wrap to zero. */
 178        max_credit = queue->remaining_credit + queue->credit_bytes;
 179        if (max_credit < queue->remaining_credit)
 180                max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
 181
 182        queue->remaining_credit = min(max_credit, max_burst);
 183        queue->rate_limited = false;
 184}
 185
 186void xenvif_tx_credit_callback(struct timer_list *t)
 187{
 188        struct xenvif_queue *queue = from_timer(queue, t, credit_timeout);
 189        tx_add_credit(queue);
 190        xenvif_napi_schedule_or_enable_events(queue);
 191}
 192
 193static void xenvif_tx_err(struct xenvif_queue *queue,
 194                          struct xen_netif_tx_request *txp,
 195                          unsigned int extra_count, RING_IDX end)
 196{
 197        RING_IDX cons = queue->tx.req_cons;
 198        unsigned long flags;
 199
 200        do {
 201                spin_lock_irqsave(&queue->response_lock, flags);
 202                make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR);
 203                push_tx_responses(queue);
 204                spin_unlock_irqrestore(&queue->response_lock, flags);
 205                if (cons == end)
 206                        break;
 207                RING_COPY_REQUEST(&queue->tx, cons++, txp);
 208                extra_count = 0; /* only the first frag can have extras */
 209        } while (1);
 210        queue->tx.req_cons = cons;
 211}
 212
 213static void xenvif_fatal_tx_err(struct xenvif *vif)
 214{
 215        netdev_err(vif->dev, "fatal error; disabling device\n");
 216        vif->disabled = true;
 217        /* Disable the vif from queue 0's kthread */
 218        if (vif->num_queues)
 219                xenvif_kick_thread(&vif->queues[0]);
 220}
 221
 222static int xenvif_count_requests(struct xenvif_queue *queue,
 223                                 struct xen_netif_tx_request *first,
 224                                 unsigned int extra_count,
 225                                 struct xen_netif_tx_request *txp,
 226                                 int work_to_do)
 227{
 228        RING_IDX cons = queue->tx.req_cons;
 229        int slots = 0;
 230        int drop_err = 0;
 231        int more_data;
 232
 233        if (!(first->flags & XEN_NETTXF_more_data))
 234                return 0;
 235
 236        do {
 237                struct xen_netif_tx_request dropped_tx = { 0 };
 238
 239                if (slots >= work_to_do) {
 240                        netdev_err(queue->vif->dev,
 241                                   "Asked for %d slots but exceeds this limit\n",
 242                                   work_to_do);
 243                        xenvif_fatal_tx_err(queue->vif);
 244                        return -ENODATA;
 245                }
 246
 247                /* This guest is really using too many slots and
 248                 * considered malicious.
 249                 */
 250                if (unlikely(slots >= fatal_skb_slots)) {
 251                        netdev_err(queue->vif->dev,
 252                                   "Malicious frontend using %d slots, threshold %u\n",
 253                                   slots, fatal_skb_slots);
 254                        xenvif_fatal_tx_err(queue->vif);
 255                        return -E2BIG;
 256                }
 257
 258                /* Xen network protocol had implicit dependency on
 259                 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
 260                 * the historical MAX_SKB_FRAGS value 18 to honor the
 261                 * same behavior as before. Any packet using more than
 262                 * 18 slots but less than fatal_skb_slots slots is
 263                 * dropped
 264                 */
 265                if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
 266                        if (net_ratelimit())
 267                                netdev_dbg(queue->vif->dev,
 268                                           "Too many slots (%d) exceeding limit (%d), dropping packet\n",
 269                                           slots, XEN_NETBK_LEGACY_SLOTS_MAX);
 270                        drop_err = -E2BIG;
 271                }
 272
 273                if (drop_err)
 274                        txp = &dropped_tx;
 275
 276                RING_COPY_REQUEST(&queue->tx, cons + slots, txp);
 277
 278                /* If the guest submitted a frame >= 64 KiB then
 279                 * first->size overflowed and following slots will
 280                 * appear to be larger than the frame.
 281                 *
 282                 * This cannot be fatal error as there are buggy
 283                 * frontends that do this.
 284                 *
 285                 * Consume all slots and drop the packet.
 286                 */
 287                if (!drop_err && txp->size > first->size) {
 288                        if (net_ratelimit())
 289                                netdev_dbg(queue->vif->dev,
 290                                           "Invalid tx request, slot size %u > remaining size %u\n",
 291                                           txp->size, first->size);
 292                        drop_err = -EIO;
 293                }
 294
 295                first->size -= txp->size;
 296                slots++;
 297
 298                if (unlikely((txp->offset + txp->size) > XEN_PAGE_SIZE)) {
 299                        netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n",
 300                                 txp->offset, txp->size);
 301                        xenvif_fatal_tx_err(queue->vif);
 302                        return -EINVAL;
 303                }
 304
 305                more_data = txp->flags & XEN_NETTXF_more_data;
 306
 307                if (!drop_err)
 308                        txp++;
 309
 310        } while (more_data);
 311
 312        if (drop_err) {
 313                xenvif_tx_err(queue, first, extra_count, cons + slots);
 314                return drop_err;
 315        }
 316
 317        return slots;
 318}
 319
 320
 321struct xenvif_tx_cb {
 322        u16 pending_idx;
 323};
 324
 325#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
 326
 327static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
 328                                           u16 pending_idx,
 329                                           struct xen_netif_tx_request *txp,
 330                                           unsigned int extra_count,
 331                                           struct gnttab_map_grant_ref *mop)
 332{
 333        queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
 334        gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
 335                          GNTMAP_host_map | GNTMAP_readonly,
 336                          txp->gref, queue->vif->domid);
 337
 338        memcpy(&queue->pending_tx_info[pending_idx].req, txp,
 339               sizeof(*txp));
 340        queue->pending_tx_info[pending_idx].extra_count = extra_count;
 341}
 342
 343static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
 344{
 345        struct sk_buff *skb =
 346                alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
 347                          GFP_ATOMIC | __GFP_NOWARN);
 348        if (unlikely(skb == NULL))
 349                return NULL;
 350
 351        /* Packets passed to netif_rx() must have some headroom. */
 352        skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
 353
 354        /* Initialize it here to avoid later surprises */
 355        skb_shinfo(skb)->destructor_arg = NULL;
 356
 357        return skb;
 358}
 359
 360static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
 361                                                        struct sk_buff *skb,
 362                                                        struct xen_netif_tx_request *txp,
 363                                                        struct gnttab_map_grant_ref *gop,
 364                                                        unsigned int frag_overflow,
 365                                                        struct sk_buff *nskb)
 366{
 367        struct skb_shared_info *shinfo = skb_shinfo(skb);
 368        skb_frag_t *frags = shinfo->frags;
 369        u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
 370        int start;
 371        pending_ring_idx_t index;
 372        unsigned int nr_slots;
 373
 374        nr_slots = shinfo->nr_frags;
 375
 376        /* Skip first skb fragment if it is on same page as header fragment. */
 377        start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
 378
 379        for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
 380             shinfo->nr_frags++, txp++, gop++) {
 381                index = pending_index(queue->pending_cons++);
 382                pending_idx = queue->pending_ring[index];
 383                xenvif_tx_create_map_op(queue, pending_idx, txp, 0, gop);
 384                frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
 385        }
 386
 387        if (frag_overflow) {
 388
 389                shinfo = skb_shinfo(nskb);
 390                frags = shinfo->frags;
 391
 392                for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
 393                     shinfo->nr_frags++, txp++, gop++) {
 394                        index = pending_index(queue->pending_cons++);
 395                        pending_idx = queue->pending_ring[index];
 396                        xenvif_tx_create_map_op(queue, pending_idx, txp, 0,
 397                                                gop);
 398                        frag_set_pending_idx(&frags[shinfo->nr_frags],
 399                                             pending_idx);
 400                }
 401
 402                skb_shinfo(skb)->frag_list = nskb;
 403        }
 404
 405        return gop;
 406}
 407
 408static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
 409                                           u16 pending_idx,
 410                                           grant_handle_t handle)
 411{
 412        if (unlikely(queue->grant_tx_handle[pending_idx] !=
 413                     NETBACK_INVALID_HANDLE)) {
 414                netdev_err(queue->vif->dev,
 415                           "Trying to overwrite active handle! pending_idx: 0x%x\n",
 416                           pending_idx);
 417                BUG();
 418        }
 419        queue->grant_tx_handle[pending_idx] = handle;
 420}
 421
 422static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
 423                                             u16 pending_idx)
 424{
 425        if (unlikely(queue->grant_tx_handle[pending_idx] ==
 426                     NETBACK_INVALID_HANDLE)) {
 427                netdev_err(queue->vif->dev,
 428                           "Trying to unmap invalid handle! pending_idx: 0x%x\n",
 429                           pending_idx);
 430                BUG();
 431        }
 432        queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
 433}
 434
 435static int xenvif_tx_check_gop(struct xenvif_queue *queue,
 436                               struct sk_buff *skb,
 437                               struct gnttab_map_grant_ref **gopp_map,
 438                               struct gnttab_copy **gopp_copy)
 439{
 440        struct gnttab_map_grant_ref *gop_map = *gopp_map;
 441        u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
 442        /* This always points to the shinfo of the skb being checked, which
 443         * could be either the first or the one on the frag_list
 444         */
 445        struct skb_shared_info *shinfo = skb_shinfo(skb);
 446        /* If this is non-NULL, we are currently checking the frag_list skb, and
 447         * this points to the shinfo of the first one
 448         */
 449        struct skb_shared_info *first_shinfo = NULL;
 450        int nr_frags = shinfo->nr_frags;
 451        const bool sharedslot = nr_frags &&
 452                                frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
 453        int i, err;
 454
 455        /* Check status of header. */
 456        err = (*gopp_copy)->status;
 457        if (unlikely(err)) {
 458                if (net_ratelimit())
 459                        netdev_dbg(queue->vif->dev,
 460                                   "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
 461                                   (*gopp_copy)->status,
 462                                   pending_idx,
 463                                   (*gopp_copy)->source.u.ref);
 464                /* The first frag might still have this slot mapped */
 465                if (!sharedslot)
 466                        xenvif_idx_release(queue, pending_idx,
 467                                           XEN_NETIF_RSP_ERROR);
 468        }
 469        (*gopp_copy)++;
 470
 471check_frags:
 472        for (i = 0; i < nr_frags; i++, gop_map++) {
 473                int j, newerr;
 474
 475                pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
 476
 477                /* Check error status: if okay then remember grant handle. */
 478                newerr = gop_map->status;
 479
 480                if (likely(!newerr)) {
 481                        xenvif_grant_handle_set(queue,
 482                                                pending_idx,
 483                                                gop_map->handle);
 484                        /* Had a previous error? Invalidate this fragment. */
 485                        if (unlikely(err)) {
 486                                xenvif_idx_unmap(queue, pending_idx);
 487                                /* If the mapping of the first frag was OK, but
 488                                 * the header's copy failed, and they are
 489                                 * sharing a slot, send an error
 490                                 */
 491                                if (i == 0 && sharedslot)
 492                                        xenvif_idx_release(queue, pending_idx,
 493                                                           XEN_NETIF_RSP_ERROR);
 494                                else
 495                                        xenvif_idx_release(queue, pending_idx,
 496                                                           XEN_NETIF_RSP_OKAY);
 497                        }
 498                        continue;
 499                }
 500
 501                /* Error on this fragment: respond to client with an error. */
 502                if (net_ratelimit())
 503                        netdev_dbg(queue->vif->dev,
 504                                   "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
 505                                   i,
 506                                   gop_map->status,
 507                                   pending_idx,
 508                                   gop_map->ref);
 509
 510                xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
 511
 512                /* Not the first error? Preceding frags already invalidated. */
 513                if (err)
 514                        continue;
 515
 516                /* First error: if the header haven't shared a slot with the
 517                 * first frag, release it as well.
 518                 */
 519                if (!sharedslot)
 520                        xenvif_idx_release(queue,
 521                                           XENVIF_TX_CB(skb)->pending_idx,
 522                                           XEN_NETIF_RSP_OKAY);
 523
 524                /* Invalidate preceding fragments of this skb. */
 525                for (j = 0; j < i; j++) {
 526                        pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
 527                        xenvif_idx_unmap(queue, pending_idx);
 528                        xenvif_idx_release(queue, pending_idx,
 529                                           XEN_NETIF_RSP_OKAY);
 530                }
 531
 532                /* And if we found the error while checking the frag_list, unmap
 533                 * the first skb's frags
 534                 */
 535                if (first_shinfo) {
 536                        for (j = 0; j < first_shinfo->nr_frags; j++) {
 537                                pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
 538                                xenvif_idx_unmap(queue, pending_idx);
 539                                xenvif_idx_release(queue, pending_idx,
 540                                                   XEN_NETIF_RSP_OKAY);
 541                        }
 542                }
 543
 544                /* Remember the error: invalidate all subsequent fragments. */
 545                err = newerr;
 546        }
 547
 548        if (skb_has_frag_list(skb) && !first_shinfo) {
 549                first_shinfo = skb_shinfo(skb);
 550                shinfo = skb_shinfo(skb_shinfo(skb)->frag_list);
 551                nr_frags = shinfo->nr_frags;
 552
 553                goto check_frags;
 554        }
 555
 556        *gopp_map = gop_map;
 557        return err;
 558}
 559
 560static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
 561{
 562        struct skb_shared_info *shinfo = skb_shinfo(skb);
 563        int nr_frags = shinfo->nr_frags;
 564        int i;
 565        u16 prev_pending_idx = INVALID_PENDING_IDX;
 566
 567        for (i = 0; i < nr_frags; i++) {
 568                skb_frag_t *frag = shinfo->frags + i;
 569                struct xen_netif_tx_request *txp;
 570                struct page *page;
 571                u16 pending_idx;
 572
 573                pending_idx = frag_get_pending_idx(frag);
 574
 575                /* If this is not the first frag, chain it to the previous*/
 576                if (prev_pending_idx == INVALID_PENDING_IDX)
 577                        skb_shinfo(skb)->destructor_arg =
 578                                &callback_param(queue, pending_idx);
 579                else
 580                        callback_param(queue, prev_pending_idx).ctx =
 581                                &callback_param(queue, pending_idx);
 582
 583                callback_param(queue, pending_idx).ctx = NULL;
 584                prev_pending_idx = pending_idx;
 585
 586                txp = &queue->pending_tx_info[pending_idx].req;
 587                page = virt_to_page(idx_to_kaddr(queue, pending_idx));
 588                __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
 589                skb->len += txp->size;
 590                skb->data_len += txp->size;
 591                skb->truesize += txp->size;
 592
 593                /* Take an extra reference to offset network stack's put_page */
 594                get_page(queue->mmap_pages[pending_idx]);
 595        }
 596}
 597
 598static int xenvif_get_extras(struct xenvif_queue *queue,
 599                             struct xen_netif_extra_info *extras,
 600                             unsigned int *extra_count,
 601                             int work_to_do)
 602{
 603        struct xen_netif_extra_info extra;
 604        RING_IDX cons = queue->tx.req_cons;
 605
 606        do {
 607                if (unlikely(work_to_do-- <= 0)) {
 608                        netdev_err(queue->vif->dev, "Missing extra info\n");
 609                        xenvif_fatal_tx_err(queue->vif);
 610                        return -EBADR;
 611                }
 612
 613                RING_COPY_REQUEST(&queue->tx, cons, &extra);
 614
 615                queue->tx.req_cons = ++cons;
 616                (*extra_count)++;
 617
 618                if (unlikely(!extra.type ||
 619                             extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 620                        netdev_err(queue->vif->dev,
 621                                   "Invalid extra type: %d\n", extra.type);
 622                        xenvif_fatal_tx_err(queue->vif);
 623                        return -EINVAL;
 624                }
 625
 626                memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
 627        } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
 628
 629        return work_to_do;
 630}
 631
 632static int xenvif_set_skb_gso(struct xenvif *vif,
 633                              struct sk_buff *skb,
 634                              struct xen_netif_extra_info *gso)
 635{
 636        if (!gso->u.gso.size) {
 637                netdev_err(vif->dev, "GSO size must not be zero.\n");
 638                xenvif_fatal_tx_err(vif);
 639                return -EINVAL;
 640        }
 641
 642        switch (gso->u.gso.type) {
 643        case XEN_NETIF_GSO_TYPE_TCPV4:
 644                skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 645                break;
 646        case XEN_NETIF_GSO_TYPE_TCPV6:
 647                skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 648                break;
 649        default:
 650                netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
 651                xenvif_fatal_tx_err(vif);
 652                return -EINVAL;
 653        }
 654
 655        skb_shinfo(skb)->gso_size = gso->u.gso.size;
 656        /* gso_segs will be calculated later */
 657
 658        return 0;
 659}
 660
 661static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
 662{
 663        bool recalculate_partial_csum = false;
 664
 665        /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 666         * peers can fail to set NETRXF_csum_blank when sending a GSO
 667         * frame. In this case force the SKB to CHECKSUM_PARTIAL and
 668         * recalculate the partial checksum.
 669         */
 670        if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
 671                queue->stats.rx_gso_checksum_fixup++;
 672                skb->ip_summed = CHECKSUM_PARTIAL;
 673                recalculate_partial_csum = true;
 674        }
 675
 676        /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
 677        if (skb->ip_summed != CHECKSUM_PARTIAL)
 678                return 0;
 679
 680        return skb_checksum_setup(skb, recalculate_partial_csum);
 681}
 682
 683static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
 684{
 685        u64 now = get_jiffies_64();
 686        u64 next_credit = queue->credit_window_start +
 687                msecs_to_jiffies(queue->credit_usec / 1000);
 688
 689        /* Timer could already be pending in rare cases. */
 690        if (timer_pending(&queue->credit_timeout)) {
 691                queue->rate_limited = true;
 692                return true;
 693        }
 694
 695        /* Passed the point where we can replenish credit? */
 696        if (time_after_eq64(now, next_credit)) {
 697                queue->credit_window_start = now;
 698                tx_add_credit(queue);
 699        }
 700
 701        /* Still too big to send right now? Set a callback. */
 702        if (size > queue->remaining_credit) {
 703                mod_timer(&queue->credit_timeout,
 704                          next_credit);
 705                queue->credit_window_start = next_credit;
 706                queue->rate_limited = true;
 707
 708                return true;
 709        }
 710
 711        return false;
 712}
 713
 714/* No locking is required in xenvif_mcast_add/del() as they are
 715 * only ever invoked from NAPI poll. An RCU list is used because
 716 * xenvif_mcast_match() is called asynchronously, during start_xmit.
 717 */
 718
 719static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
 720{
 721        struct xenvif_mcast_addr *mcast;
 722
 723        if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
 724                if (net_ratelimit())
 725                        netdev_err(vif->dev,
 726                                   "Too many multicast addresses\n");
 727                return -ENOSPC;
 728        }
 729
 730        mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
 731        if (!mcast)
 732                return -ENOMEM;
 733
 734        ether_addr_copy(mcast->addr, addr);
 735        list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
 736        vif->fe_mcast_count++;
 737
 738        return 0;
 739}
 740
 741static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
 742{
 743        struct xenvif_mcast_addr *mcast;
 744
 745        list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
 746                if (ether_addr_equal(addr, mcast->addr)) {
 747                        --vif->fe_mcast_count;
 748                        list_del_rcu(&mcast->entry);
 749                        kfree_rcu(mcast, rcu);
 750                        break;
 751                }
 752        }
 753}
 754
 755bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
 756{
 757        struct xenvif_mcast_addr *mcast;
 758
 759        rcu_read_lock();
 760        list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
 761                if (ether_addr_equal(addr, mcast->addr)) {
 762                        rcu_read_unlock();
 763                        return true;
 764                }
 765        }
 766        rcu_read_unlock();
 767
 768        return false;
 769}
 770
 771void xenvif_mcast_addr_list_free(struct xenvif *vif)
 772{
 773        /* No need for locking or RCU here. NAPI poll and TX queue
 774         * are stopped.
 775         */
 776        while (!list_empty(&vif->fe_mcast_addr)) {
 777                struct xenvif_mcast_addr *mcast;
 778
 779                mcast = list_first_entry(&vif->fe_mcast_addr,
 780                                         struct xenvif_mcast_addr,
 781                                         entry);
 782                --vif->fe_mcast_count;
 783                list_del(&mcast->entry);
 784                kfree(mcast);
 785        }
 786}
 787
 788static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 789                                     int budget,
 790                                     unsigned *copy_ops,
 791                                     unsigned *map_ops)
 792{
 793        struct gnttab_map_grant_ref *gop = queue->tx_map_ops;
 794        struct sk_buff *skb, *nskb;
 795        int ret;
 796        unsigned int frag_overflow;
 797
 798        while (skb_queue_len(&queue->tx_queue) < budget) {
 799                struct xen_netif_tx_request txreq;
 800                struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
 801                struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
 802                unsigned int extra_count;
 803                u16 pending_idx;
 804                RING_IDX idx;
 805                int work_to_do;
 806                unsigned int data_len;
 807                pending_ring_idx_t index;
 808
 809                if (queue->tx.sring->req_prod - queue->tx.req_cons >
 810                    XEN_NETIF_TX_RING_SIZE) {
 811                        netdev_err(queue->vif->dev,
 812                                   "Impossible number of requests. "
 813                                   "req_prod %d, req_cons %d, size %ld\n",
 814                                   queue->tx.sring->req_prod, queue->tx.req_cons,
 815                                   XEN_NETIF_TX_RING_SIZE);
 816                        xenvif_fatal_tx_err(queue->vif);
 817                        break;
 818                }
 819
 820                work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
 821                if (!work_to_do)
 822                        break;
 823
 824                idx = queue->tx.req_cons;
 825                rmb(); /* Ensure that we see the request before we copy it. */
 826                RING_COPY_REQUEST(&queue->tx, idx, &txreq);
 827
 828                /* Credit-based scheduling. */
 829                if (txreq.size > queue->remaining_credit &&
 830                    tx_credit_exceeded(queue, txreq.size))
 831                        break;
 832
 833                queue->remaining_credit -= txreq.size;
 834
 835                work_to_do--;
 836                queue->tx.req_cons = ++idx;
 837
 838                memset(extras, 0, sizeof(extras));
 839                extra_count = 0;
 840                if (txreq.flags & XEN_NETTXF_extra_info) {
 841                        work_to_do = xenvif_get_extras(queue, extras,
 842                                                       &extra_count,
 843                                                       work_to_do);
 844                        idx = queue->tx.req_cons;
 845                        if (unlikely(work_to_do < 0))
 846                                break;
 847                }
 848
 849                if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
 850                        struct xen_netif_extra_info *extra;
 851
 852                        extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
 853                        ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
 854
 855                        make_tx_response(queue, &txreq, extra_count,
 856                                         (ret == 0) ?
 857                                         XEN_NETIF_RSP_OKAY :
 858                                         XEN_NETIF_RSP_ERROR);
 859                        push_tx_responses(queue);
 860                        continue;
 861                }
 862
 863                if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
 864                        struct xen_netif_extra_info *extra;
 865
 866                        extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
 867                        xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
 868
 869                        make_tx_response(queue, &txreq, extra_count,
 870                                         XEN_NETIF_RSP_OKAY);
 871                        push_tx_responses(queue);
 872                        continue;
 873                }
 874
 875                ret = xenvif_count_requests(queue, &txreq, extra_count,
 876                                            txfrags, work_to_do);
 877                if (unlikely(ret < 0))
 878                        break;
 879
 880                idx += ret;
 881
 882                if (unlikely(txreq.size < ETH_HLEN)) {
 883                        netdev_dbg(queue->vif->dev,
 884                                   "Bad packet size: %d\n", txreq.size);
 885                        xenvif_tx_err(queue, &txreq, extra_count, idx);
 886                        break;
 887                }
 888
 889                /* No crossing a page as the payload mustn't fragment. */
 890                if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
 891                        netdev_err(queue->vif->dev,
 892                                   "txreq.offset: %u, size: %u, end: %lu\n",
 893                                   txreq.offset, txreq.size,
 894                                   (unsigned long)(txreq.offset&~XEN_PAGE_MASK) + txreq.size);
 895                        xenvif_fatal_tx_err(queue->vif);
 896                        break;
 897                }
 898
 899                index = pending_index(queue->pending_cons);
 900                pending_idx = queue->pending_ring[index];
 901
 902                data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
 903                            ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
 904                        XEN_NETBACK_TX_COPY_LEN : txreq.size;
 905
 906                skb = xenvif_alloc_skb(data_len);
 907                if (unlikely(skb == NULL)) {
 908                        netdev_dbg(queue->vif->dev,
 909                                   "Can't allocate a skb in start_xmit.\n");
 910                        xenvif_tx_err(queue, &txreq, extra_count, idx);
 911                        break;
 912                }
 913
 914                skb_shinfo(skb)->nr_frags = ret;
 915                if (data_len < txreq.size)
 916                        skb_shinfo(skb)->nr_frags++;
 917                /* At this point shinfo->nr_frags is in fact the number of
 918                 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
 919                 */
 920                frag_overflow = 0;
 921                nskb = NULL;
 922                if (skb_shinfo(skb)->nr_frags > MAX_SKB_FRAGS) {
 923                        frag_overflow = skb_shinfo(skb)->nr_frags - MAX_SKB_FRAGS;
 924                        BUG_ON(frag_overflow > MAX_SKB_FRAGS);
 925                        skb_shinfo(skb)->nr_frags = MAX_SKB_FRAGS;
 926                        nskb = xenvif_alloc_skb(0);
 927                        if (unlikely(nskb == NULL)) {
 928                                kfree_skb(skb);
 929                                xenvif_tx_err(queue, &txreq, extra_count, idx);
 930                                if (net_ratelimit())
 931                                        netdev_err(queue->vif->dev,
 932                                                   "Can't allocate the frag_list skb.\n");
 933                                break;
 934                        }
 935                }
 936
 937                if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
 938                        struct xen_netif_extra_info *gso;
 939                        gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
 940
 941                        if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
 942                                /* Failure in xenvif_set_skb_gso is fatal. */
 943                                kfree_skb(skb);
 944                                kfree_skb(nskb);
 945                                break;
 946                        }
 947                }
 948
 949                if (extras[XEN_NETIF_EXTRA_TYPE_HASH - 1].type) {
 950                        struct xen_netif_extra_info *extra;
 951                        enum pkt_hash_types type = PKT_HASH_TYPE_NONE;
 952
 953                        extra = &extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
 954
 955                        switch (extra->u.hash.type) {
 956                        case _XEN_NETIF_CTRL_HASH_TYPE_IPV4:
 957                        case _XEN_NETIF_CTRL_HASH_TYPE_IPV6:
 958                                type = PKT_HASH_TYPE_L3;
 959                                break;
 960
 961                        case _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP:
 962                        case _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP:
 963                                type = PKT_HASH_TYPE_L4;
 964                                break;
 965
 966                        default:
 967                                break;
 968                        }
 969
 970                        if (type != PKT_HASH_TYPE_NONE)
 971                                skb_set_hash(skb,
 972                                             *(u32 *)extra->u.hash.value,
 973                                             type);
 974                }
 975
 976                XENVIF_TX_CB(skb)->pending_idx = pending_idx;
 977
 978                __skb_put(skb, data_len);
 979                queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
 980                queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
 981                queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
 982
 983                queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
 984                        virt_to_gfn(skb->data);
 985                queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
 986                queue->tx_copy_ops[*copy_ops].dest.offset =
 987                        offset_in_page(skb->data) & ~XEN_PAGE_MASK;
 988
 989                queue->tx_copy_ops[*copy_ops].len = data_len;
 990                queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
 991
 992                (*copy_ops)++;
 993
 994                if (data_len < txreq.size) {
 995                        frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
 996                                             pending_idx);
 997                        xenvif_tx_create_map_op(queue, pending_idx, &txreq,
 998                                                extra_count, gop);
 999                        gop++;
1000                } else {
1001                        frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1002                                             INVALID_PENDING_IDX);
1003                        memcpy(&queue->pending_tx_info[pending_idx].req,
1004                               &txreq, sizeof(txreq));
1005                        queue->pending_tx_info[pending_idx].extra_count =
1006                                extra_count;
1007                }
1008
1009                queue->pending_cons++;
1010
1011                gop = xenvif_get_requests(queue, skb, txfrags, gop,
1012                                          frag_overflow, nskb);
1013
1014                __skb_queue_tail(&queue->tx_queue, skb);
1015
1016                queue->tx.req_cons = idx;
1017
1018                if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
1019                    (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
1020                        break;
1021        }
1022
1023        (*map_ops) = gop - queue->tx_map_ops;
1024        return;
1025}
1026
1027/* Consolidate skb with a frag_list into a brand new one with local pages on
1028 * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1029 */
1030static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1031{
1032        unsigned int offset = skb_headlen(skb);
1033        skb_frag_t frags[MAX_SKB_FRAGS];
1034        int i, f;
1035        struct ubuf_info *uarg;
1036        struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1037
1038        queue->stats.tx_zerocopy_sent += 2;
1039        queue->stats.tx_frag_overflow++;
1040
1041        xenvif_fill_frags(queue, nskb);
1042        /* Subtract frags size, we will correct it later */
1043        skb->truesize -= skb->data_len;
1044        skb->len += nskb->len;
1045        skb->data_len += nskb->len;
1046
1047        /* create a brand new frags array and coalesce there */
1048        for (i = 0; offset < skb->len; i++) {
1049                struct page *page;
1050                unsigned int len;
1051
1052                BUG_ON(i >= MAX_SKB_FRAGS);
1053                page = alloc_page(GFP_ATOMIC);
1054                if (!page) {
1055                        int j;
1056                        skb->truesize += skb->data_len;
1057                        for (j = 0; j < i; j++)
1058                                put_page(frags[j].page.p);
1059                        return -ENOMEM;
1060                }
1061
1062                if (offset + PAGE_SIZE < skb->len)
1063                        len = PAGE_SIZE;
1064                else
1065                        len = skb->len - offset;
1066                if (skb_copy_bits(skb, offset, page_address(page), len))
1067                        BUG();
1068
1069                offset += len;
1070                frags[i].page.p = page;
1071                frags[i].page_offset = 0;
1072                skb_frag_size_set(&frags[i], len);
1073        }
1074
1075        /* Copied all the bits from the frag list -- free it. */
1076        skb_frag_list_init(skb);
1077        xenvif_skb_zerocopy_prepare(queue, nskb);
1078        kfree_skb(nskb);
1079
1080        /* Release all the original (foreign) frags. */
1081        for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
1082                skb_frag_unref(skb, f);
1083        uarg = skb_shinfo(skb)->destructor_arg;
1084        /* increase inflight counter to offset decrement in callback */
1085        atomic_inc(&queue->inflight_packets);
1086        uarg->callback(uarg, true);
1087        skb_shinfo(skb)->destructor_arg = NULL;
1088
1089        /* Fill the skb with the new (local) frags. */
1090        memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
1091        skb_shinfo(skb)->nr_frags = i;
1092        skb->truesize += i * PAGE_SIZE;
1093
1094        return 0;
1095}
1096
1097static int xenvif_tx_submit(struct xenvif_queue *queue)
1098{
1099        struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1100        struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1101        struct sk_buff *skb;
1102        int work_done = 0;
1103
1104        while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1105                struct xen_netif_tx_request *txp;
1106                u16 pending_idx;
1107                unsigned data_len;
1108
1109                pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1110                txp = &queue->pending_tx_info[pending_idx].req;
1111
1112                /* Check the remap error code. */
1113                if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1114                        /* If there was an error, xenvif_tx_check_gop is
1115                         * expected to release all the frags which were mapped,
1116                         * so kfree_skb shouldn't do it again
1117                         */
1118                        skb_shinfo(skb)->nr_frags = 0;
1119                        if (skb_has_frag_list(skb)) {
1120                                struct sk_buff *nskb =
1121                                                skb_shinfo(skb)->frag_list;
1122                                skb_shinfo(nskb)->nr_frags = 0;
1123                        }
1124                        kfree_skb(skb);
1125                        continue;
1126                }
1127
1128                data_len = skb->len;
1129                callback_param(queue, pending_idx).ctx = NULL;
1130                if (data_len < txp->size) {
1131                        /* Append the packet payload as a fragment. */
1132                        txp->offset += data_len;
1133                        txp->size -= data_len;
1134                } else {
1135                        /* Schedule a response immediately. */
1136                        xenvif_idx_release(queue, pending_idx,
1137                                           XEN_NETIF_RSP_OKAY);
1138                }
1139
1140                if (txp->flags & XEN_NETTXF_csum_blank)
1141                        skb->ip_summed = CHECKSUM_PARTIAL;
1142                else if (txp->flags & XEN_NETTXF_data_validated)
1143                        skb->ip_summed = CHECKSUM_UNNECESSARY;
1144
1145                xenvif_fill_frags(queue, skb);
1146
1147                if (unlikely(skb_has_frag_list(skb))) {
1148                        if (xenvif_handle_frag_list(queue, skb)) {
1149                                if (net_ratelimit())
1150                                        netdev_err(queue->vif->dev,
1151                                                   "Not enough memory to consolidate frag_list!\n");
1152                                xenvif_skb_zerocopy_prepare(queue, skb);
1153                                kfree_skb(skb);
1154                                continue;
1155                        }
1156                }
1157
1158                skb->dev      = queue->vif->dev;
1159                skb->protocol = eth_type_trans(skb, skb->dev);
1160                skb_reset_network_header(skb);
1161
1162                if (checksum_setup(queue, skb)) {
1163                        netdev_dbg(queue->vif->dev,
1164                                   "Can't setup checksum in net_tx_action\n");
1165                        /* We have to set this flag to trigger the callback */
1166                        if (skb_shinfo(skb)->destructor_arg)
1167                                xenvif_skb_zerocopy_prepare(queue, skb);
1168                        kfree_skb(skb);
1169                        continue;
1170                }
1171
1172                skb_probe_transport_header(skb, 0);
1173
1174                /* If the packet is GSO then we will have just set up the
1175                 * transport header offset in checksum_setup so it's now
1176                 * straightforward to calculate gso_segs.
1177                 */
1178                if (skb_is_gso(skb)) {
1179                        int mss = skb_shinfo(skb)->gso_size;
1180                        int hdrlen = skb_transport_header(skb) -
1181                                skb_mac_header(skb) +
1182                                tcp_hdrlen(skb);
1183
1184                        skb_shinfo(skb)->gso_segs =
1185                                DIV_ROUND_UP(skb->len - hdrlen, mss);
1186                }
1187
1188                queue->stats.rx_bytes += skb->len;
1189                queue->stats.rx_packets++;
1190
1191                work_done++;
1192
1193                /* Set this flag right before netif_receive_skb, otherwise
1194                 * someone might think this packet already left netback, and
1195                 * do a skb_copy_ubufs while we are still in control of the
1196                 * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1197                 */
1198                if (skb_shinfo(skb)->destructor_arg) {
1199                        xenvif_skb_zerocopy_prepare(queue, skb);
1200                        queue->stats.tx_zerocopy_sent++;
1201                }
1202
1203                netif_receive_skb(skb);
1204        }
1205
1206        return work_done;
1207}
1208
1209void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
1210{
1211        unsigned long flags;
1212        pending_ring_idx_t index;
1213        struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1214
1215        /* This is the only place where we grab this lock, to protect callbacks
1216         * from each other.
1217         */
1218        spin_lock_irqsave(&queue->callback_lock, flags);
1219        do {
1220                u16 pending_idx = ubuf->desc;
1221                ubuf = (struct ubuf_info *) ubuf->ctx;
1222                BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1223                        MAX_PENDING_REQS);
1224                index = pending_index(queue->dealloc_prod);
1225                queue->dealloc_ring[index] = pending_idx;
1226                /* Sync with xenvif_tx_dealloc_action:
1227                 * insert idx then incr producer.
1228                 */
1229                smp_wmb();
1230                queue->dealloc_prod++;
1231        } while (ubuf);
1232        spin_unlock_irqrestore(&queue->callback_lock, flags);
1233
1234        if (likely(zerocopy_success))
1235                queue->stats.tx_zerocopy_success++;
1236        else
1237                queue->stats.tx_zerocopy_fail++;
1238        xenvif_skb_zerocopy_complete(queue);
1239}
1240
1241static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1242{
1243        struct gnttab_unmap_grant_ref *gop;
1244        pending_ring_idx_t dc, dp;
1245        u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1246        unsigned int i = 0;
1247
1248        dc = queue->dealloc_cons;
1249        gop = queue->tx_unmap_ops;
1250
1251        /* Free up any grants we have finished using */
1252        do {
1253                dp = queue->dealloc_prod;
1254
1255                /* Ensure we see all indices enqueued by all
1256                 * xenvif_zerocopy_callback().
1257                 */
1258                smp_rmb();
1259
1260                while (dc != dp) {
1261                        BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS);
1262                        pending_idx =
1263                                queue->dealloc_ring[pending_index(dc++)];
1264
1265                        pending_idx_release[gop - queue->tx_unmap_ops] =
1266                                pending_idx;
1267                        queue->pages_to_unmap[gop - queue->tx_unmap_ops] =
1268                                queue->mmap_pages[pending_idx];
1269                        gnttab_set_unmap_op(gop,
1270                                            idx_to_kaddr(queue, pending_idx),
1271                                            GNTMAP_host_map,
1272                                            queue->grant_tx_handle[pending_idx]);
1273                        xenvif_grant_handle_reset(queue, pending_idx);
1274                        ++gop;
1275                }
1276
1277        } while (dp != queue->dealloc_prod);
1278
1279        queue->dealloc_cons = dc;
1280
1281        if (gop - queue->tx_unmap_ops > 0) {
1282                int ret;
1283                ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1284                                        NULL,
1285                                        queue->pages_to_unmap,
1286                                        gop - queue->tx_unmap_ops);
1287                if (ret) {
1288                        netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tu ret %d\n",
1289                                   gop - queue->tx_unmap_ops, ret);
1290                        for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1291                                if (gop[i].status != GNTST_okay)
1292                                        netdev_err(queue->vif->dev,
1293                                                   " host_addr: 0x%llx handle: 0x%x status: %d\n",
1294                                                   gop[i].host_addr,
1295                                                   gop[i].handle,
1296                                                   gop[i].status);
1297                        }
1298                        BUG();
1299                }
1300        }
1301
1302        for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1303                xenvif_idx_release(queue, pending_idx_release[i],
1304                                   XEN_NETIF_RSP_OKAY);
1305}
1306
1307
1308/* Called after netfront has transmitted */
1309int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1310{
1311        unsigned nr_mops, nr_cops = 0;
1312        int work_done, ret;
1313
1314        if (unlikely(!tx_work_todo(queue)))
1315                return 0;
1316
1317        xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1318
1319        if (nr_cops == 0)
1320                return 0;
1321
1322        gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1323        if (nr_mops != 0) {
1324                ret = gnttab_map_refs(queue->tx_map_ops,
1325                                      NULL,
1326                                      queue->pages_to_map,
1327                                      nr_mops);
1328                BUG_ON(ret);
1329        }
1330
1331        work_done = xenvif_tx_submit(queue);
1332
1333        return work_done;
1334}
1335
1336static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1337                               u8 status)
1338{
1339        struct pending_tx_info *pending_tx_info;
1340        pending_ring_idx_t index;
1341        unsigned long flags;
1342
1343        pending_tx_info = &queue->pending_tx_info[pending_idx];
1344
1345        spin_lock_irqsave(&queue->response_lock, flags);
1346
1347        make_tx_response(queue, &pending_tx_info->req,
1348                         pending_tx_info->extra_count, status);
1349
1350        /* Release the pending index before pusing the Tx response so
1351         * its available before a new Tx request is pushed by the
1352         * frontend.
1353         */
1354        index = pending_index(queue->pending_prod++);
1355        queue->pending_ring[index] = pending_idx;
1356
1357        push_tx_responses(queue);
1358
1359        spin_unlock_irqrestore(&queue->response_lock, flags);
1360}
1361
1362
1363static void make_tx_response(struct xenvif_queue *queue,
1364                             struct xen_netif_tx_request *txp,
1365                             unsigned int extra_count,
1366                             s8       st)
1367{
1368        RING_IDX i = queue->tx.rsp_prod_pvt;
1369        struct xen_netif_tx_response *resp;
1370
1371        resp = RING_GET_RESPONSE(&queue->tx, i);
1372        resp->id     = txp->id;
1373        resp->status = st;
1374
1375        while (extra_count-- != 0)
1376                RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1377
1378        queue->tx.rsp_prod_pvt = ++i;
1379}
1380
1381static void push_tx_responses(struct xenvif_queue *queue)
1382{
1383        int notify;
1384
1385        RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1386        if (notify)
1387                notify_remote_via_irq(queue->tx_irq);
1388}
1389
1390void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1391{
1392        int ret;
1393        struct gnttab_unmap_grant_ref tx_unmap_op;
1394
1395        gnttab_set_unmap_op(&tx_unmap_op,
1396                            idx_to_kaddr(queue, pending_idx),
1397                            GNTMAP_host_map,
1398                            queue->grant_tx_handle[pending_idx]);
1399        xenvif_grant_handle_reset(queue, pending_idx);
1400
1401        ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1402                                &queue->mmap_pages[pending_idx], 1);
1403        if (ret) {
1404                netdev_err(queue->vif->dev,
1405                           "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: 0x%x status: %d\n",
1406                           ret,
1407                           pending_idx,
1408                           tx_unmap_op.host_addr,
1409                           tx_unmap_op.handle,
1410                           tx_unmap_op.status);
1411                BUG();
1412        }
1413}
1414
1415static inline int tx_work_todo(struct xenvif_queue *queue)
1416{
1417        if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1418                return 1;
1419
1420        return 0;
1421}
1422
1423static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1424{
1425        return queue->dealloc_cons != queue->dealloc_prod;
1426}
1427
1428void xenvif_unmap_frontend_data_rings(struct xenvif_queue *queue)
1429{
1430        if (queue->tx.sring)
1431                xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1432                                        queue->tx.sring);
1433        if (queue->rx.sring)
1434                xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1435                                        queue->rx.sring);
1436}
1437
1438int xenvif_map_frontend_data_rings(struct xenvif_queue *queue,
1439                                   grant_ref_t tx_ring_ref,
1440                                   grant_ref_t rx_ring_ref)
1441{
1442        void *addr;
1443        struct xen_netif_tx_sring *txs;
1444        struct xen_netif_rx_sring *rxs;
1445
1446        int err = -ENOMEM;
1447
1448        err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1449                                     &tx_ring_ref, 1, &addr);
1450        if (err)
1451                goto err;
1452
1453        txs = (struct xen_netif_tx_sring *)addr;
1454        BACK_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
1455
1456        err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1457                                     &rx_ring_ref, 1, &addr);
1458        if (err)
1459                goto err;
1460
1461        rxs = (struct xen_netif_rx_sring *)addr;
1462        BACK_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
1463
1464        return 0;
1465
1466err:
1467        xenvif_unmap_frontend_data_rings(queue);
1468        return err;
1469}
1470
1471static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
1472{
1473        /* Dealloc thread must remain running until all inflight
1474         * packets complete.
1475         */
1476        return kthread_should_stop() &&
1477                !atomic_read(&queue->inflight_packets);
1478}
1479
1480int xenvif_dealloc_kthread(void *data)
1481{
1482        struct xenvif_queue *queue = data;
1483
1484        for (;;) {
1485                wait_event_interruptible(queue->dealloc_wq,
1486                                         tx_dealloc_work_todo(queue) ||
1487                                         xenvif_dealloc_kthread_should_stop(queue));
1488                if (xenvif_dealloc_kthread_should_stop(queue))
1489                        break;
1490
1491                xenvif_tx_dealloc_action(queue);
1492                cond_resched();
1493        }
1494
1495        /* Unmap anything remaining*/
1496        if (tx_dealloc_work_todo(queue))
1497                xenvif_tx_dealloc_action(queue);
1498
1499        return 0;
1500}
1501
1502static void make_ctrl_response(struct xenvif *vif,
1503                               const struct xen_netif_ctrl_request *req,
1504                               u32 status, u32 data)
1505{
1506        RING_IDX idx = vif->ctrl.rsp_prod_pvt;
1507        struct xen_netif_ctrl_response rsp = {
1508                .id = req->id,
1509                .type = req->type,
1510                .status = status,
1511                .data = data,
1512        };
1513
1514        *RING_GET_RESPONSE(&vif->ctrl, idx) = rsp;
1515        vif->ctrl.rsp_prod_pvt = ++idx;
1516}
1517
1518static void push_ctrl_response(struct xenvif *vif)
1519{
1520        int notify;
1521
1522        RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->ctrl, notify);
1523        if (notify)
1524                notify_remote_via_irq(vif->ctrl_irq);
1525}
1526
1527static void process_ctrl_request(struct xenvif *vif,
1528                                 const struct xen_netif_ctrl_request *req)
1529{
1530        u32 status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED;
1531        u32 data = 0;
1532
1533        switch (req->type) {
1534        case XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM:
1535                status = xenvif_set_hash_alg(vif, req->data[0]);
1536                break;
1537
1538        case XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS:
1539                status = xenvif_get_hash_flags(vif, &data);
1540                break;
1541
1542        case XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS:
1543                status = xenvif_set_hash_flags(vif, req->data[0]);
1544                break;
1545
1546        case XEN_NETIF_CTRL_TYPE_SET_HASH_KEY:
1547                status = xenvif_set_hash_key(vif, req->data[0],
1548                                             req->data[1]);
1549                break;
1550
1551        case XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE:
1552                status = XEN_NETIF_CTRL_STATUS_SUCCESS;
1553                data = XEN_NETBK_MAX_HASH_MAPPING_SIZE;
1554                break;
1555
1556        case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE:
1557                status = xenvif_set_hash_mapping_size(vif,
1558                                                      req->data[0]);
1559                break;
1560
1561        case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING:
1562                status = xenvif_set_hash_mapping(vif, req->data[0],
1563                                                 req->data[1],
1564                                                 req->data[2]);
1565                break;
1566
1567        default:
1568                break;
1569        }
1570
1571        make_ctrl_response(vif, req, status, data);
1572        push_ctrl_response(vif);
1573}
1574
1575static void xenvif_ctrl_action(struct xenvif *vif)
1576{
1577        for (;;) {
1578                RING_IDX req_prod, req_cons;
1579
1580                req_prod = vif->ctrl.sring->req_prod;
1581                req_cons = vif->ctrl.req_cons;
1582
1583                /* Make sure we can see requests before we process them. */
1584                rmb();
1585
1586                if (req_cons == req_prod)
1587                        break;
1588
1589                while (req_cons != req_prod) {
1590                        struct xen_netif_ctrl_request req;
1591
1592                        RING_COPY_REQUEST(&vif->ctrl, req_cons, &req);
1593                        req_cons++;
1594
1595                        process_ctrl_request(vif, &req);
1596                }
1597
1598                vif->ctrl.req_cons = req_cons;
1599                vif->ctrl.sring->req_event = req_cons + 1;
1600        }
1601}
1602
1603static bool xenvif_ctrl_work_todo(struct xenvif *vif)
1604{
1605        if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->ctrl)))
1606                return 1;
1607
1608        return 0;
1609}
1610
1611irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data)
1612{
1613        struct xenvif *vif = data;
1614
1615        while (xenvif_ctrl_work_todo(vif))
1616                xenvif_ctrl_action(vif);
1617
1618        return IRQ_HANDLED;
1619}
1620
1621static int __init netback_init(void)
1622{
1623        int rc = 0;
1624
1625        if (!xen_domain())
1626                return -ENODEV;
1627
1628        /* Allow as many queues as there are CPUs but max. 8 if user has not
1629         * specified a value.
1630         */
1631        if (xenvif_max_queues == 0)
1632                xenvif_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
1633                                          num_online_cpus());
1634
1635        if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1636                pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1637                        fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1638                fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1639        }
1640
1641        rc = xenvif_xenbus_init();
1642        if (rc)
1643                goto failed_init;
1644
1645#ifdef CONFIG_DEBUG_FS
1646        xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
1647        if (IS_ERR_OR_NULL(xen_netback_dbg_root))
1648                pr_warn("Init of debugfs returned %ld!\n",
1649                        PTR_ERR(xen_netback_dbg_root));
1650#endif /* CONFIG_DEBUG_FS */
1651
1652        return 0;
1653
1654failed_init:
1655        return rc;
1656}
1657
1658module_init(netback_init);
1659
1660static void __exit netback_fini(void)
1661{
1662#ifdef CONFIG_DEBUG_FS
1663        if (!IS_ERR_OR_NULL(xen_netback_dbg_root))
1664                debugfs_remove_recursive(xen_netback_dbg_root);
1665#endif /* CONFIG_DEBUG_FS */
1666        xenvif_xenbus_fini();
1667}
1668module_exit(netback_fini);
1669
1670MODULE_LICENSE("Dual BSD/GPL");
1671MODULE_ALIAS("xen-backend:vif");
1672