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
  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 */
 103bool provides_xdp_headroom = true;
 104module_param(provides_xdp_headroom, bool, 0644);
 105
 106static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
 107                               u8 status);
 108
 109static void make_tx_response(struct xenvif_queue *queue,
 110                             struct xen_netif_tx_request *txp,
 111                             unsigned int extra_count,
 112                             s8       st);
 113static void push_tx_responses(struct xenvif_queue *queue);
 114
 115static inline int tx_work_todo(struct xenvif_queue *queue);
 116
 117static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
 118                                       u16 idx)
 119{
 120        return page_to_pfn(queue->mmap_pages[idx]);
 121}
 122
 123static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
 124                                         u16 idx)
 125{
 126        return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
 127}
 128
 129#define callback_param(vif, pending_idx) \
 130        (vif->pending_tx_info[pending_idx].callback_struct)
 131
 132/* Find the containing VIF's structure from a pointer in pending_tx_info array
 133 */
 134static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
 135{
 136        u16 pending_idx = ubuf->desc;
 137        struct pending_tx_info *temp =
 138                container_of(ubuf, struct pending_tx_info, callback_struct);
 139        return container_of(temp - pending_idx,
 140                            struct xenvif_queue,
 141                            pending_tx_info[0]);
 142}
 143
 144static u16 frag_get_pending_idx(skb_frag_t *frag)
 145{
 146        return (u16)skb_frag_off(frag);
 147}
 148
 149static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
 150{
 151        skb_frag_off_set(frag, pending_idx);
 152}
 153
 154static inline pending_ring_idx_t pending_index(unsigned i)
 155{
 156        return i & (MAX_PENDING_REQS-1);
 157}
 158
 159void xenvif_kick_thread(struct xenvif_queue *queue)
 160{
 161        wake_up(&queue->wq);
 162}
 163
 164void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
 165{
 166        int more_to_do;
 167
 168        RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
 169
 170        if (more_to_do)
 171                napi_schedule(&queue->napi);
 172        else if (atomic_fetch_andnot(NETBK_TX_EOI | NETBK_COMMON_EOI,
 173                                     &queue->eoi_pending) &
 174                 (NETBK_TX_EOI | NETBK_COMMON_EOI))
 175                xen_irq_lateeoi(queue->tx_irq, 0);
 176}
 177
 178static void tx_add_credit(struct xenvif_queue *queue)
 179{
 180        unsigned long max_burst, max_credit;
 181
 182        /*
 183         * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
 184         * Otherwise the interface can seize up due to insufficient credit.
 185         */
 186        max_burst = max(131072UL, queue->credit_bytes);
 187
 188        /* Take care that adding a new chunk of credit doesn't wrap to zero. */
 189        max_credit = queue->remaining_credit + queue->credit_bytes;
 190        if (max_credit < queue->remaining_credit)
 191                max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
 192
 193        queue->remaining_credit = min(max_credit, max_burst);
 194        queue->rate_limited = false;
 195}
 196
 197void xenvif_tx_credit_callback(struct timer_list *t)
 198{
 199        struct xenvif_queue *queue = from_timer(queue, t, credit_timeout);
 200        tx_add_credit(queue);
 201        xenvif_napi_schedule_or_enable_events(queue);
 202}
 203
 204static void xenvif_tx_err(struct xenvif_queue *queue,
 205                          struct xen_netif_tx_request *txp,
 206                          unsigned int extra_count, RING_IDX end)
 207{
 208        RING_IDX cons = queue->tx.req_cons;
 209        unsigned long flags;
 210
 211        do {
 212                spin_lock_irqsave(&queue->response_lock, flags);
 213                make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR);
 214                push_tx_responses(queue);
 215                spin_unlock_irqrestore(&queue->response_lock, flags);
 216                if (cons == end)
 217                        break;
 218                RING_COPY_REQUEST(&queue->tx, cons++, txp);
 219                extra_count = 0; /* only the first frag can have extras */
 220        } while (1);
 221        queue->tx.req_cons = cons;
 222}
 223
 224static void xenvif_fatal_tx_err(struct xenvif *vif)
 225{
 226        netdev_err(vif->dev, "fatal error; disabling device\n");
 227        vif->disabled = true;
 228        /* Disable the vif from queue 0's kthread */
 229        if (vif->num_queues)
 230                xenvif_kick_thread(&vif->queues[0]);
 231}
 232
 233static int xenvif_count_requests(struct xenvif_queue *queue,
 234                                 struct xen_netif_tx_request *first,
 235                                 unsigned int extra_count,
 236                                 struct xen_netif_tx_request *txp,
 237                                 int work_to_do)
 238{
 239        RING_IDX cons = queue->tx.req_cons;
 240        int slots = 0;
 241        int drop_err = 0;
 242        int more_data;
 243
 244        if (!(first->flags & XEN_NETTXF_more_data))
 245                return 0;
 246
 247        do {
 248                struct xen_netif_tx_request dropped_tx = { 0 };
 249
 250                if (slots >= work_to_do) {
 251                        netdev_err(queue->vif->dev,
 252                                   "Asked for %d slots but exceeds this limit\n",
 253                                   work_to_do);
 254                        xenvif_fatal_tx_err(queue->vif);
 255                        return -ENODATA;
 256                }
 257
 258                /* This guest is really using too many slots and
 259                 * considered malicious.
 260                 */
 261                if (unlikely(slots >= fatal_skb_slots)) {
 262                        netdev_err(queue->vif->dev,
 263                                   "Malicious frontend using %d slots, threshold %u\n",
 264                                   slots, fatal_skb_slots);
 265                        xenvif_fatal_tx_err(queue->vif);
 266                        return -E2BIG;
 267                }
 268
 269                /* Xen network protocol had implicit dependency on
 270                 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
 271                 * the historical MAX_SKB_FRAGS value 18 to honor the
 272                 * same behavior as before. Any packet using more than
 273                 * 18 slots but less than fatal_skb_slots slots is
 274                 * dropped
 275                 */
 276                if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
 277                        if (net_ratelimit())
 278                                netdev_dbg(queue->vif->dev,
 279                                           "Too many slots (%d) exceeding limit (%d), dropping packet\n",
 280                                           slots, XEN_NETBK_LEGACY_SLOTS_MAX);
 281                        drop_err = -E2BIG;
 282                }
 283
 284                if (drop_err)
 285                        txp = &dropped_tx;
 286
 287                RING_COPY_REQUEST(&queue->tx, cons + slots, txp);
 288
 289                /* If the guest submitted a frame >= 64 KiB then
 290                 * first->size overflowed and following slots will
 291                 * appear to be larger than the frame.
 292                 *
 293                 * This cannot be fatal error as there are buggy
 294                 * frontends that do this.
 295                 *
 296                 * Consume all slots and drop the packet.
 297                 */
 298                if (!drop_err && txp->size > first->size) {
 299                        if (net_ratelimit())
 300                                netdev_dbg(queue->vif->dev,
 301                                           "Invalid tx request, slot size %u > remaining size %u\n",
 302                                           txp->size, first->size);
 303                        drop_err = -EIO;
 304                }
 305
 306                first->size -= txp->size;
 307                slots++;
 308
 309                if (unlikely((txp->offset + txp->size) > XEN_PAGE_SIZE)) {
 310                        netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n",
 311                                 txp->offset, txp->size);
 312                        xenvif_fatal_tx_err(queue->vif);
 313                        return -EINVAL;
 314                }
 315
 316                more_data = txp->flags & XEN_NETTXF_more_data;
 317
 318                if (!drop_err)
 319                        txp++;
 320
 321        } while (more_data);
 322
 323        if (drop_err) {
 324                xenvif_tx_err(queue, first, extra_count, cons + slots);
 325                return drop_err;
 326        }
 327
 328        return slots;
 329}
 330
 331
 332struct xenvif_tx_cb {
 333        u16 pending_idx;
 334};
 335
 336#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
 337
 338static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
 339                                           u16 pending_idx,
 340                                           struct xen_netif_tx_request *txp,
 341                                           unsigned int extra_count,
 342                                           struct gnttab_map_grant_ref *mop)
 343{
 344        queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
 345        gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
 346                          GNTMAP_host_map | GNTMAP_readonly,
 347                          txp->gref, queue->vif->domid);
 348
 349        memcpy(&queue->pending_tx_info[pending_idx].req, txp,
 350               sizeof(*txp));
 351        queue->pending_tx_info[pending_idx].extra_count = extra_count;
 352}
 353
 354static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
 355{
 356        struct sk_buff *skb =
 357                alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
 358                          GFP_ATOMIC | __GFP_NOWARN);
 359        if (unlikely(skb == NULL))
 360                return NULL;
 361
 362        /* Packets passed to netif_rx() must have some headroom. */
 363        skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
 364
 365        /* Initialize it here to avoid later surprises */
 366        skb_shinfo(skb)->destructor_arg = NULL;
 367
 368        return skb;
 369}
 370
 371static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
 372                                                        struct sk_buff *skb,
 373                                                        struct xen_netif_tx_request *txp,
 374                                                        struct gnttab_map_grant_ref *gop,
 375                                                        unsigned int frag_overflow,
 376                                                        struct sk_buff *nskb)
 377{
 378        struct skb_shared_info *shinfo = skb_shinfo(skb);
 379        skb_frag_t *frags = shinfo->frags;
 380        u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
 381        int start;
 382        pending_ring_idx_t index;
 383        unsigned int nr_slots;
 384
 385        nr_slots = shinfo->nr_frags;
 386
 387        /* Skip first skb fragment if it is on same page as header fragment. */
 388        start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
 389
 390        for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
 391             shinfo->nr_frags++, txp++, gop++) {
 392                index = pending_index(queue->pending_cons++);
 393                pending_idx = queue->pending_ring[index];
 394                xenvif_tx_create_map_op(queue, pending_idx, txp, 0, gop);
 395                frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
 396        }
 397
 398        if (frag_overflow) {
 399
 400                shinfo = skb_shinfo(nskb);
 401                frags = shinfo->frags;
 402
 403                for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
 404                     shinfo->nr_frags++, txp++, gop++) {
 405                        index = pending_index(queue->pending_cons++);
 406                        pending_idx = queue->pending_ring[index];
 407                        xenvif_tx_create_map_op(queue, pending_idx, txp, 0,
 408                                                gop);
 409                        frag_set_pending_idx(&frags[shinfo->nr_frags],
 410                                             pending_idx);
 411                }
 412
 413                skb_shinfo(skb)->frag_list = nskb;
 414        }
 415
 416        return gop;
 417}
 418
 419static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
 420                                           u16 pending_idx,
 421                                           grant_handle_t handle)
 422{
 423        if (unlikely(queue->grant_tx_handle[pending_idx] !=
 424                     NETBACK_INVALID_HANDLE)) {
 425                netdev_err(queue->vif->dev,
 426                           "Trying to overwrite active handle! pending_idx: 0x%x\n",
 427                           pending_idx);
 428                BUG();
 429        }
 430        queue->grant_tx_handle[pending_idx] = handle;
 431}
 432
 433static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
 434                                             u16 pending_idx)
 435{
 436        if (unlikely(queue->grant_tx_handle[pending_idx] ==
 437                     NETBACK_INVALID_HANDLE)) {
 438                netdev_err(queue->vif->dev,
 439                           "Trying to unmap invalid handle! pending_idx: 0x%x\n",
 440                           pending_idx);
 441                BUG();
 442        }
 443        queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
 444}
 445
 446static int xenvif_tx_check_gop(struct xenvif_queue *queue,
 447                               struct sk_buff *skb,
 448                               struct gnttab_map_grant_ref **gopp_map,
 449                               struct gnttab_copy **gopp_copy)
 450{
 451        struct gnttab_map_grant_ref *gop_map = *gopp_map;
 452        u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
 453        /* This always points to the shinfo of the skb being checked, which
 454         * could be either the first or the one on the frag_list
 455         */
 456        struct skb_shared_info *shinfo = skb_shinfo(skb);
 457        /* If this is non-NULL, we are currently checking the frag_list skb, and
 458         * this points to the shinfo of the first one
 459         */
 460        struct skb_shared_info *first_shinfo = NULL;
 461        int nr_frags = shinfo->nr_frags;
 462        const bool sharedslot = nr_frags &&
 463                                frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
 464        int i, err;
 465
 466        /* Check status of header. */
 467        err = (*gopp_copy)->status;
 468        if (unlikely(err)) {
 469                if (net_ratelimit())
 470                        netdev_dbg(queue->vif->dev,
 471                                   "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
 472                                   (*gopp_copy)->status,
 473                                   pending_idx,
 474                                   (*gopp_copy)->source.u.ref);
 475                /* The first frag might still have this slot mapped */
 476                if (!sharedslot)
 477                        xenvif_idx_release(queue, pending_idx,
 478                                           XEN_NETIF_RSP_ERROR);
 479        }
 480        (*gopp_copy)++;
 481
 482check_frags:
 483        for (i = 0; i < nr_frags; i++, gop_map++) {
 484                int j, newerr;
 485
 486                pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
 487
 488                /* Check error status: if okay then remember grant handle. */
 489                newerr = gop_map->status;
 490
 491                if (likely(!newerr)) {
 492                        xenvif_grant_handle_set(queue,
 493                                                pending_idx,
 494                                                gop_map->handle);
 495                        /* Had a previous error? Invalidate this fragment. */
 496                        if (unlikely(err)) {
 497                                xenvif_idx_unmap(queue, pending_idx);
 498                                /* If the mapping of the first frag was OK, but
 499                                 * the header's copy failed, and they are
 500                                 * sharing a slot, send an error
 501                                 */
 502                                if (i == 0 && sharedslot)
 503                                        xenvif_idx_release(queue, pending_idx,
 504                                                           XEN_NETIF_RSP_ERROR);
 505                                else
 506                                        xenvif_idx_release(queue, pending_idx,
 507                                                           XEN_NETIF_RSP_OKAY);
 508                        }
 509                        continue;
 510                }
 511
 512                /* Error on this fragment: respond to client with an error. */
 513                if (net_ratelimit())
 514                        netdev_dbg(queue->vif->dev,
 515                                   "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
 516                                   i,
 517                                   gop_map->status,
 518                                   pending_idx,
 519                                   gop_map->ref);
 520
 521                xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
 522
 523                /* Not the first error? Preceding frags already invalidated. */
 524                if (err)
 525                        continue;
 526
 527                /* First error: if the header haven't shared a slot with the
 528                 * first frag, release it as well.
 529                 */
 530                if (!sharedslot)
 531                        xenvif_idx_release(queue,
 532                                           XENVIF_TX_CB(skb)->pending_idx,
 533                                           XEN_NETIF_RSP_OKAY);
 534
 535                /* Invalidate preceding fragments of this skb. */
 536                for (j = 0; j < i; j++) {
 537                        pending_idx = frag_get_pending_idx(&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                /* And if we found the error while checking the frag_list, unmap
 544                 * the first skb's frags
 545                 */
 546                if (first_shinfo) {
 547                        for (j = 0; j < first_shinfo->nr_frags; j++) {
 548                                pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
 549                                xenvif_idx_unmap(queue, pending_idx);
 550                                xenvif_idx_release(queue, pending_idx,
 551                                                   XEN_NETIF_RSP_OKAY);
 552                        }
 553                }
 554
 555                /* Remember the error: invalidate all subsequent fragments. */
 556                err = newerr;
 557        }
 558
 559        if (skb_has_frag_list(skb) && !first_shinfo) {
 560                first_shinfo = shinfo;
 561                shinfo = skb_shinfo(shinfo->frag_list);
 562                nr_frags = shinfo->nr_frags;
 563
 564                goto check_frags;
 565        }
 566
 567        *gopp_map = gop_map;
 568        return err;
 569}
 570
 571static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
 572{
 573        struct skb_shared_info *shinfo = skb_shinfo(skb);
 574        int nr_frags = shinfo->nr_frags;
 575        int i;
 576        u16 prev_pending_idx = INVALID_PENDING_IDX;
 577
 578        for (i = 0; i < nr_frags; i++) {
 579                skb_frag_t *frag = shinfo->frags + i;
 580                struct xen_netif_tx_request *txp;
 581                struct page *page;
 582                u16 pending_idx;
 583
 584                pending_idx = frag_get_pending_idx(frag);
 585
 586                /* If this is not the first frag, chain it to the previous*/
 587                if (prev_pending_idx == INVALID_PENDING_IDX)
 588                        skb_shinfo(skb)->destructor_arg =
 589                                &callback_param(queue, pending_idx);
 590                else
 591                        callback_param(queue, prev_pending_idx).ctx =
 592                                &callback_param(queue, pending_idx);
 593
 594                callback_param(queue, pending_idx).ctx = NULL;
 595                prev_pending_idx = pending_idx;
 596
 597                txp = &queue->pending_tx_info[pending_idx].req;
 598                page = virt_to_page(idx_to_kaddr(queue, pending_idx));
 599                __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
 600                skb->len += txp->size;
 601                skb->data_len += txp->size;
 602                skb->truesize += txp->size;
 603
 604                /* Take an extra reference to offset network stack's put_page */
 605                get_page(queue->mmap_pages[pending_idx]);
 606        }
 607}
 608
 609static int xenvif_get_extras(struct xenvif_queue *queue,
 610                             struct xen_netif_extra_info *extras,
 611                             unsigned int *extra_count,
 612                             int work_to_do)
 613{
 614        struct xen_netif_extra_info extra;
 615        RING_IDX cons = queue->tx.req_cons;
 616
 617        do {
 618                if (unlikely(work_to_do-- <= 0)) {
 619                        netdev_err(queue->vif->dev, "Missing extra info\n");
 620                        xenvif_fatal_tx_err(queue->vif);
 621                        return -EBADR;
 622                }
 623
 624                RING_COPY_REQUEST(&queue->tx, cons, &extra);
 625
 626                queue->tx.req_cons = ++cons;
 627                (*extra_count)++;
 628
 629                if (unlikely(!extra.type ||
 630                             extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 631                        netdev_err(queue->vif->dev,
 632                                   "Invalid extra type: %d\n", extra.type);
 633                        xenvif_fatal_tx_err(queue->vif);
 634                        return -EINVAL;
 635                }
 636
 637                memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
 638        } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
 639
 640        return work_to_do;
 641}
 642
 643static int xenvif_set_skb_gso(struct xenvif *vif,
 644                              struct sk_buff *skb,
 645                              struct xen_netif_extra_info *gso)
 646{
 647        if (!gso->u.gso.size) {
 648                netdev_err(vif->dev, "GSO size must not be zero.\n");
 649                xenvif_fatal_tx_err(vif);
 650                return -EINVAL;
 651        }
 652
 653        switch (gso->u.gso.type) {
 654        case XEN_NETIF_GSO_TYPE_TCPV4:
 655                skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 656                break;
 657        case XEN_NETIF_GSO_TYPE_TCPV6:
 658                skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 659                break;
 660        default:
 661                netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
 662                xenvif_fatal_tx_err(vif);
 663                return -EINVAL;
 664        }
 665
 666        skb_shinfo(skb)->gso_size = gso->u.gso.size;
 667        /* gso_segs will be calculated later */
 668
 669        return 0;
 670}
 671
 672static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
 673{
 674        bool recalculate_partial_csum = false;
 675
 676        /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 677         * peers can fail to set NETRXF_csum_blank when sending a GSO
 678         * frame. In this case force the SKB to CHECKSUM_PARTIAL and
 679         * recalculate the partial checksum.
 680         */
 681        if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
 682                queue->stats.rx_gso_checksum_fixup++;
 683                skb->ip_summed = CHECKSUM_PARTIAL;
 684                recalculate_partial_csum = true;
 685        }
 686
 687        /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
 688        if (skb->ip_summed != CHECKSUM_PARTIAL)
 689                return 0;
 690
 691        return skb_checksum_setup(skb, recalculate_partial_csum);
 692}
 693
 694static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
 695{
 696        u64 now = get_jiffies_64();
 697        u64 next_credit = queue->credit_window_start +
 698                msecs_to_jiffies(queue->credit_usec / 1000);
 699
 700        /* Timer could already be pending in rare cases. */
 701        if (timer_pending(&queue->credit_timeout)) {
 702                queue->rate_limited = true;
 703                return true;
 704        }
 705
 706        /* Passed the point where we can replenish credit? */
 707        if (time_after_eq64(now, next_credit)) {
 708                queue->credit_window_start = now;
 709                tx_add_credit(queue);
 710        }
 711
 712        /* Still too big to send right now? Set a callback. */
 713        if (size > queue->remaining_credit) {
 714                mod_timer(&queue->credit_timeout,
 715                          next_credit);
 716                queue->credit_window_start = next_credit;
 717                queue->rate_limited = true;
 718
 719                return true;
 720        }
 721
 722        return false;
 723}
 724
 725/* No locking is required in xenvif_mcast_add/del() as they are
 726 * only ever invoked from NAPI poll. An RCU list is used because
 727 * xenvif_mcast_match() is called asynchronously, during start_xmit.
 728 */
 729
 730static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
 731{
 732        struct xenvif_mcast_addr *mcast;
 733
 734        if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
 735                if (net_ratelimit())
 736                        netdev_err(vif->dev,
 737                                   "Too many multicast addresses\n");
 738                return -ENOSPC;
 739        }
 740
 741        mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
 742        if (!mcast)
 743                return -ENOMEM;
 744
 745        ether_addr_copy(mcast->addr, addr);
 746        list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
 747        vif->fe_mcast_count++;
 748
 749        return 0;
 750}
 751
 752static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
 753{
 754        struct xenvif_mcast_addr *mcast;
 755
 756        list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
 757                if (ether_addr_equal(addr, mcast->addr)) {
 758                        --vif->fe_mcast_count;
 759                        list_del_rcu(&mcast->entry);
 760                        kfree_rcu(mcast, rcu);
 761                        break;
 762                }
 763        }
 764}
 765
 766bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
 767{
 768        struct xenvif_mcast_addr *mcast;
 769
 770        rcu_read_lock();
 771        list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
 772                if (ether_addr_equal(addr, mcast->addr)) {
 773                        rcu_read_unlock();
 774                        return true;
 775                }
 776        }
 777        rcu_read_unlock();
 778
 779        return false;
 780}
 781
 782void xenvif_mcast_addr_list_free(struct xenvif *vif)
 783{
 784        /* No need for locking or RCU here. NAPI poll and TX queue
 785         * are stopped.
 786         */
 787        while (!list_empty(&vif->fe_mcast_addr)) {
 788                struct xenvif_mcast_addr *mcast;
 789
 790                mcast = list_first_entry(&vif->fe_mcast_addr,
 791                                         struct xenvif_mcast_addr,
 792                                         entry);
 793                --vif->fe_mcast_count;
 794                list_del(&mcast->entry);
 795                kfree(mcast);
 796        }
 797}
 798
 799static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 800                                     int budget,
 801                                     unsigned *copy_ops,
 802                                     unsigned *map_ops)
 803{
 804        struct gnttab_map_grant_ref *gop = queue->tx_map_ops;
 805        struct sk_buff *skb, *nskb;
 806        int ret;
 807        unsigned int frag_overflow;
 808
 809        while (skb_queue_len(&queue->tx_queue) < budget) {
 810                struct xen_netif_tx_request txreq;
 811                struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
 812                struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
 813                unsigned int extra_count;
 814                u16 pending_idx;
 815                RING_IDX idx;
 816                int work_to_do;
 817                unsigned int data_len;
 818                pending_ring_idx_t index;
 819
 820                if (queue->tx.sring->req_prod - queue->tx.req_cons >
 821                    XEN_NETIF_TX_RING_SIZE) {
 822                        netdev_err(queue->vif->dev,
 823                                   "Impossible number of requests. "
 824                                   "req_prod %d, req_cons %d, size %ld\n",
 825                                   queue->tx.sring->req_prod, queue->tx.req_cons,
 826                                   XEN_NETIF_TX_RING_SIZE);
 827                        xenvif_fatal_tx_err(queue->vif);
 828                        break;
 829                }
 830
 831                work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
 832                if (!work_to_do)
 833                        break;
 834
 835                idx = queue->tx.req_cons;
 836                rmb(); /* Ensure that we see the request before we copy it. */
 837                RING_COPY_REQUEST(&queue->tx, idx, &txreq);
 838
 839                /* Credit-based scheduling. */
 840                if (txreq.size > queue->remaining_credit &&
 841                    tx_credit_exceeded(queue, txreq.size))
 842                        break;
 843
 844                queue->remaining_credit -= txreq.size;
 845
 846                work_to_do--;
 847                queue->tx.req_cons = ++idx;
 848
 849                memset(extras, 0, sizeof(extras));
 850                extra_count = 0;
 851                if (txreq.flags & XEN_NETTXF_extra_info) {
 852                        work_to_do = xenvif_get_extras(queue, extras,
 853                                                       &extra_count,
 854                                                       work_to_do);
 855                        idx = queue->tx.req_cons;
 856                        if (unlikely(work_to_do < 0))
 857                                break;
 858                }
 859
 860                if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
 861                        struct xen_netif_extra_info *extra;
 862
 863                        extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
 864                        ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
 865
 866                        make_tx_response(queue, &txreq, extra_count,
 867                                         (ret == 0) ?
 868                                         XEN_NETIF_RSP_OKAY :
 869                                         XEN_NETIF_RSP_ERROR);
 870                        push_tx_responses(queue);
 871                        continue;
 872                }
 873
 874                if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
 875                        struct xen_netif_extra_info *extra;
 876
 877                        extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
 878                        xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
 879
 880                        make_tx_response(queue, &txreq, extra_count,
 881                                         XEN_NETIF_RSP_OKAY);
 882                        push_tx_responses(queue);
 883                        continue;
 884                }
 885
 886                ret = xenvif_count_requests(queue, &txreq, extra_count,
 887                                            txfrags, work_to_do);
 888                if (unlikely(ret < 0))
 889                        break;
 890
 891                idx += ret;
 892
 893                if (unlikely(txreq.size < ETH_HLEN)) {
 894                        netdev_dbg(queue->vif->dev,
 895                                   "Bad packet size: %d\n", txreq.size);
 896                        xenvif_tx_err(queue, &txreq, extra_count, idx);
 897                        break;
 898                }
 899
 900                /* No crossing a page as the payload mustn't fragment. */
 901                if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
 902                        netdev_err(queue->vif->dev,
 903                                   "txreq.offset: %u, size: %u, end: %lu\n",
 904                                   txreq.offset, txreq.size,
 905                                   (unsigned long)(txreq.offset&~XEN_PAGE_MASK) + txreq.size);
 906                        xenvif_fatal_tx_err(queue->vif);
 907                        break;
 908                }
 909
 910                index = pending_index(queue->pending_cons);
 911                pending_idx = queue->pending_ring[index];
 912
 913                data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
 914                            ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
 915                        XEN_NETBACK_TX_COPY_LEN : txreq.size;
 916
 917                skb = xenvif_alloc_skb(data_len);
 918                if (unlikely(skb == NULL)) {
 919                        netdev_dbg(queue->vif->dev,
 920                                   "Can't allocate a skb in start_xmit.\n");
 921                        xenvif_tx_err(queue, &txreq, extra_count, idx);
 922                        break;
 923                }
 924
 925                skb_shinfo(skb)->nr_frags = ret;
 926                if (data_len < txreq.size)
 927                        skb_shinfo(skb)->nr_frags++;
 928                /* At this point shinfo->nr_frags is in fact the number of
 929                 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
 930                 */
 931                frag_overflow = 0;
 932                nskb = NULL;
 933                if (skb_shinfo(skb)->nr_frags > MAX_SKB_FRAGS) {
 934                        frag_overflow = skb_shinfo(skb)->nr_frags - MAX_SKB_FRAGS;
 935                        BUG_ON(frag_overflow > MAX_SKB_FRAGS);
 936                        skb_shinfo(skb)->nr_frags = MAX_SKB_FRAGS;
 937                        nskb = xenvif_alloc_skb(0);
 938                        if (unlikely(nskb == NULL)) {
 939                                skb_shinfo(skb)->nr_frags = 0;
 940                                kfree_skb(skb);
 941                                xenvif_tx_err(queue, &txreq, extra_count, idx);
 942                                if (net_ratelimit())
 943                                        netdev_err(queue->vif->dev,
 944                                                   "Can't allocate the frag_list skb.\n");
 945                                break;
 946                        }
 947                }
 948
 949                if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
 950                        struct xen_netif_extra_info *gso;
 951                        gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
 952
 953                        if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
 954                                /* Failure in xenvif_set_skb_gso is fatal. */
 955                                skb_shinfo(skb)->nr_frags = 0;
 956                                kfree_skb(skb);
 957                                kfree_skb(nskb);
 958                                break;
 959                        }
 960                }
 961
 962                if (extras[XEN_NETIF_EXTRA_TYPE_HASH - 1].type) {
 963                        struct xen_netif_extra_info *extra;
 964                        enum pkt_hash_types type = PKT_HASH_TYPE_NONE;
 965
 966                        extra = &extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
 967
 968                        switch (extra->u.hash.type) {
 969                        case _XEN_NETIF_CTRL_HASH_TYPE_IPV4:
 970                        case _XEN_NETIF_CTRL_HASH_TYPE_IPV6:
 971                                type = PKT_HASH_TYPE_L3;
 972                                break;
 973
 974                        case _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP:
 975                        case _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP:
 976                                type = PKT_HASH_TYPE_L4;
 977                                break;
 978
 979                        default:
 980                                break;
 981                        }
 982
 983                        if (type != PKT_HASH_TYPE_NONE)
 984                                skb_set_hash(skb,
 985                                             *(u32 *)extra->u.hash.value,
 986                                             type);
 987                }
 988
 989                XENVIF_TX_CB(skb)->pending_idx = pending_idx;
 990
 991                __skb_put(skb, data_len);
 992                queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
 993                queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
 994                queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
 995
 996                queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
 997                        virt_to_gfn(skb->data);
 998                queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
 999                queue->tx_copy_ops[*copy_ops].dest.offset =
1000                        offset_in_page(skb->data) & ~XEN_PAGE_MASK;
1001
1002                queue->tx_copy_ops[*copy_ops].len = data_len;
1003                queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
1004
1005                (*copy_ops)++;
1006
1007                if (data_len < txreq.size) {
1008                        frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1009                                             pending_idx);
1010                        xenvif_tx_create_map_op(queue, pending_idx, &txreq,
1011                                                extra_count, gop);
1012                        gop++;
1013                } else {
1014                        frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1015                                             INVALID_PENDING_IDX);
1016                        memcpy(&queue->pending_tx_info[pending_idx].req,
1017                               &txreq, sizeof(txreq));
1018                        queue->pending_tx_info[pending_idx].extra_count =
1019                                extra_count;
1020                }
1021
1022                queue->pending_cons++;
1023
1024                gop = xenvif_get_requests(queue, skb, txfrags, gop,
1025                                          frag_overflow, nskb);
1026
1027                __skb_queue_tail(&queue->tx_queue, skb);
1028
1029                queue->tx.req_cons = idx;
1030
1031                if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
1032                    (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
1033                        break;
1034        }
1035
1036        (*map_ops) = gop - queue->tx_map_ops;
1037        return;
1038}
1039
1040/* Consolidate skb with a frag_list into a brand new one with local pages on
1041 * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1042 */
1043static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1044{
1045        unsigned int offset = skb_headlen(skb);
1046        skb_frag_t frags[MAX_SKB_FRAGS];
1047        int i, f;
1048        struct ubuf_info *uarg;
1049        struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1050
1051        queue->stats.tx_zerocopy_sent += 2;
1052        queue->stats.tx_frag_overflow++;
1053
1054        xenvif_fill_frags(queue, nskb);
1055        /* Subtract frags size, we will correct it later */
1056        skb->truesize -= skb->data_len;
1057        skb->len += nskb->len;
1058        skb->data_len += nskb->len;
1059
1060        /* create a brand new frags array and coalesce there */
1061        for (i = 0; offset < skb->len; i++) {
1062                struct page *page;
1063                unsigned int len;
1064
1065                BUG_ON(i >= MAX_SKB_FRAGS);
1066                page = alloc_page(GFP_ATOMIC);
1067                if (!page) {
1068                        int j;
1069                        skb->truesize += skb->data_len;
1070                        for (j = 0; j < i; j++)
1071                                put_page(skb_frag_page(&frags[j]));
1072                        return -ENOMEM;
1073                }
1074
1075                if (offset + PAGE_SIZE < skb->len)
1076                        len = PAGE_SIZE;
1077                else
1078                        len = skb->len - offset;
1079                if (skb_copy_bits(skb, offset, page_address(page), len))
1080                        BUG();
1081
1082                offset += len;
1083                __skb_frag_set_page(&frags[i], page);
1084                skb_frag_off_set(&frags[i], 0);
1085                skb_frag_size_set(&frags[i], len);
1086        }
1087
1088        /* Release all the original (foreign) frags. */
1089        for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
1090                skb_frag_unref(skb, f);
1091        uarg = skb_shinfo(skb)->destructor_arg;
1092        /* increase inflight counter to offset decrement in callback */
1093        atomic_inc(&queue->inflight_packets);
1094        uarg->callback(NULL, uarg, true);
1095        skb_shinfo(skb)->destructor_arg = NULL;
1096
1097        /* Fill the skb with the new (local) frags. */
1098        memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
1099        skb_shinfo(skb)->nr_frags = i;
1100        skb->truesize += i * PAGE_SIZE;
1101
1102        return 0;
1103}
1104
1105static int xenvif_tx_submit(struct xenvif_queue *queue)
1106{
1107        struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1108        struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1109        struct sk_buff *skb;
1110        int work_done = 0;
1111
1112        while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1113                struct xen_netif_tx_request *txp;
1114                u16 pending_idx;
1115                unsigned data_len;
1116
1117                pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1118                txp = &queue->pending_tx_info[pending_idx].req;
1119
1120                /* Check the remap error code. */
1121                if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1122                        /* If there was an error, xenvif_tx_check_gop is
1123                         * expected to release all the frags which were mapped,
1124                         * so kfree_skb shouldn't do it again
1125                         */
1126                        skb_shinfo(skb)->nr_frags = 0;
1127                        if (skb_has_frag_list(skb)) {
1128                                struct sk_buff *nskb =
1129                                                skb_shinfo(skb)->frag_list;
1130                                skb_shinfo(nskb)->nr_frags = 0;
1131                        }
1132                        kfree_skb(skb);
1133                        continue;
1134                }
1135
1136                data_len = skb->len;
1137                callback_param(queue, pending_idx).ctx = NULL;
1138                if (data_len < txp->size) {
1139                        /* Append the packet payload as a fragment. */
1140                        txp->offset += data_len;
1141                        txp->size -= data_len;
1142                } else {
1143                        /* Schedule a response immediately. */
1144                        xenvif_idx_release(queue, pending_idx,
1145                                           XEN_NETIF_RSP_OKAY);
1146                }
1147
1148                if (txp->flags & XEN_NETTXF_csum_blank)
1149                        skb->ip_summed = CHECKSUM_PARTIAL;
1150                else if (txp->flags & XEN_NETTXF_data_validated)
1151                        skb->ip_summed = CHECKSUM_UNNECESSARY;
1152
1153                xenvif_fill_frags(queue, skb);
1154
1155                if (unlikely(skb_has_frag_list(skb))) {
1156                        struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1157                        xenvif_skb_zerocopy_prepare(queue, nskb);
1158                        if (xenvif_handle_frag_list(queue, skb)) {
1159                                if (net_ratelimit())
1160                                        netdev_err(queue->vif->dev,
1161                                                   "Not enough memory to consolidate frag_list!\n");
1162                                xenvif_skb_zerocopy_prepare(queue, skb);
1163                                kfree_skb(skb);
1164                                continue;
1165                        }
1166                        /* Copied all the bits from the frag list -- free it. */
1167                        skb_frag_list_init(skb);
1168                        kfree_skb(nskb);
1169                }
1170
1171                skb->dev      = queue->vif->dev;
1172                skb->protocol = eth_type_trans(skb, skb->dev);
1173                skb_reset_network_header(skb);
1174
1175                if (checksum_setup(queue, skb)) {
1176                        netdev_dbg(queue->vif->dev,
1177                                   "Can't setup checksum in net_tx_action\n");
1178                        /* We have to set this flag to trigger the callback */
1179                        if (skb_shinfo(skb)->destructor_arg)
1180                                xenvif_skb_zerocopy_prepare(queue, skb);
1181                        kfree_skb(skb);
1182                        continue;
1183                }
1184
1185                skb_probe_transport_header(skb);
1186
1187                /* If the packet is GSO then we will have just set up the
1188                 * transport header offset in checksum_setup so it's now
1189                 * straightforward to calculate gso_segs.
1190                 */
1191                if (skb_is_gso(skb)) {
1192                        int mss, hdrlen;
1193
1194                        /* GSO implies having the L4 header. */
1195                        WARN_ON_ONCE(!skb_transport_header_was_set(skb));
1196                        if (unlikely(!skb_transport_header_was_set(skb))) {
1197                                kfree_skb(skb);
1198                                continue;
1199                        }
1200
1201                        mss = skb_shinfo(skb)->gso_size;
1202                        hdrlen = skb_transport_header(skb) -
1203                                skb_mac_header(skb) +
1204                                tcp_hdrlen(skb);
1205
1206                        skb_shinfo(skb)->gso_segs =
1207                                DIV_ROUND_UP(skb->len - hdrlen, mss);
1208                }
1209
1210                queue->stats.rx_bytes += skb->len;
1211                queue->stats.rx_packets++;
1212
1213                work_done++;
1214
1215                /* Set this flag right before netif_receive_skb, otherwise
1216                 * someone might think this packet already left netback, and
1217                 * do a skb_copy_ubufs while we are still in control of the
1218                 * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1219                 */
1220                if (skb_shinfo(skb)->destructor_arg) {
1221                        xenvif_skb_zerocopy_prepare(queue, skb);
1222                        queue->stats.tx_zerocopy_sent++;
1223                }
1224
1225                netif_receive_skb(skb);
1226        }
1227
1228        return work_done;
1229}
1230
1231void xenvif_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *ubuf,
1232                              bool zerocopy_success)
1233{
1234        unsigned long flags;
1235        pending_ring_idx_t index;
1236        struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1237
1238        /* This is the only place where we grab this lock, to protect callbacks
1239         * from each other.
1240         */
1241        spin_lock_irqsave(&queue->callback_lock, flags);
1242        do {
1243                u16 pending_idx = ubuf->desc;
1244                ubuf = (struct ubuf_info *) ubuf->ctx;
1245                BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1246                        MAX_PENDING_REQS);
1247                index = pending_index(queue->dealloc_prod);
1248                queue->dealloc_ring[index] = pending_idx;
1249                /* Sync with xenvif_tx_dealloc_action:
1250                 * insert idx then incr producer.
1251                 */
1252                smp_wmb();
1253                queue->dealloc_prod++;
1254        } while (ubuf);
1255        spin_unlock_irqrestore(&queue->callback_lock, flags);
1256
1257        if (likely(zerocopy_success))
1258                queue->stats.tx_zerocopy_success++;
1259        else
1260                queue->stats.tx_zerocopy_fail++;
1261        xenvif_skb_zerocopy_complete(queue);
1262}
1263
1264static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1265{
1266        struct gnttab_unmap_grant_ref *gop;
1267        pending_ring_idx_t dc, dp;
1268        u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1269        unsigned int i = 0;
1270
1271        dc = queue->dealloc_cons;
1272        gop = queue->tx_unmap_ops;
1273
1274        /* Free up any grants we have finished using */
1275        do {
1276                dp = queue->dealloc_prod;
1277
1278                /* Ensure we see all indices enqueued by all
1279                 * xenvif_zerocopy_callback().
1280                 */
1281                smp_rmb();
1282
1283                while (dc != dp) {
1284                        BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS);
1285                        pending_idx =
1286                                queue->dealloc_ring[pending_index(dc++)];
1287
1288                        pending_idx_release[gop - queue->tx_unmap_ops] =
1289                                pending_idx;
1290                        queue->pages_to_unmap[gop - queue->tx_unmap_ops] =
1291                                queue->mmap_pages[pending_idx];
1292                        gnttab_set_unmap_op(gop,
1293                                            idx_to_kaddr(queue, pending_idx),
1294                                            GNTMAP_host_map,
1295                                            queue->grant_tx_handle[pending_idx]);
1296                        xenvif_grant_handle_reset(queue, pending_idx);
1297                        ++gop;
1298                }
1299
1300        } while (dp != queue->dealloc_prod);
1301
1302        queue->dealloc_cons = dc;
1303
1304        if (gop - queue->tx_unmap_ops > 0) {
1305                int ret;
1306                ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1307                                        NULL,
1308                                        queue->pages_to_unmap,
1309                                        gop - queue->tx_unmap_ops);
1310                if (ret) {
1311                        netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tu ret %d\n",
1312                                   gop - queue->tx_unmap_ops, ret);
1313                        for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1314                                if (gop[i].status != GNTST_okay)
1315                                        netdev_err(queue->vif->dev,
1316                                                   " host_addr: 0x%llx handle: 0x%x status: %d\n",
1317                                                   gop[i].host_addr,
1318                                                   gop[i].handle,
1319                                                   gop[i].status);
1320                        }
1321                        BUG();
1322                }
1323        }
1324
1325        for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1326                xenvif_idx_release(queue, pending_idx_release[i],
1327                                   XEN_NETIF_RSP_OKAY);
1328}
1329
1330
1331/* Called after netfront has transmitted */
1332int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1333{
1334        unsigned nr_mops, nr_cops = 0;
1335        int work_done, ret;
1336
1337        if (unlikely(!tx_work_todo(queue)))
1338                return 0;
1339
1340        xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1341
1342        if (nr_cops == 0)
1343                return 0;
1344
1345        gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1346        if (nr_mops != 0) {
1347                ret = gnttab_map_refs(queue->tx_map_ops,
1348                                      NULL,
1349                                      queue->pages_to_map,
1350                                      nr_mops);
1351                if (ret) {
1352                        unsigned int i;
1353
1354                        netdev_err(queue->vif->dev, "Map fail: nr %u ret %d\n",
1355                                   nr_mops, ret);
1356                        for (i = 0; i < nr_mops; ++i)
1357                                WARN_ON_ONCE(queue->tx_map_ops[i].status ==
1358                                             GNTST_okay);
1359                }
1360        }
1361
1362        work_done = xenvif_tx_submit(queue);
1363
1364        return work_done;
1365}
1366
1367static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1368                               u8 status)
1369{
1370        struct pending_tx_info *pending_tx_info;
1371        pending_ring_idx_t index;
1372        unsigned long flags;
1373
1374        pending_tx_info = &queue->pending_tx_info[pending_idx];
1375
1376        spin_lock_irqsave(&queue->response_lock, flags);
1377
1378        make_tx_response(queue, &pending_tx_info->req,
1379                         pending_tx_info->extra_count, status);
1380
1381        /* Release the pending index before pusing the Tx response so
1382         * its available before a new Tx request is pushed by the
1383         * frontend.
1384         */
1385        index = pending_index(queue->pending_prod++);
1386        queue->pending_ring[index] = pending_idx;
1387
1388        push_tx_responses(queue);
1389
1390        spin_unlock_irqrestore(&queue->response_lock, flags);
1391}
1392
1393
1394static void make_tx_response(struct xenvif_queue *queue,
1395                             struct xen_netif_tx_request *txp,
1396                             unsigned int extra_count,
1397                             s8       st)
1398{
1399        RING_IDX i = queue->tx.rsp_prod_pvt;
1400        struct xen_netif_tx_response *resp;
1401
1402        resp = RING_GET_RESPONSE(&queue->tx, i);
1403        resp->id     = txp->id;
1404        resp->status = st;
1405
1406        while (extra_count-- != 0)
1407                RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1408
1409        queue->tx.rsp_prod_pvt = ++i;
1410}
1411
1412static void push_tx_responses(struct xenvif_queue *queue)
1413{
1414        int notify;
1415
1416        RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1417        if (notify)
1418                notify_remote_via_irq(queue->tx_irq);
1419}
1420
1421void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1422{
1423        int ret;
1424        struct gnttab_unmap_grant_ref tx_unmap_op;
1425
1426        gnttab_set_unmap_op(&tx_unmap_op,
1427                            idx_to_kaddr(queue, pending_idx),
1428                            GNTMAP_host_map,
1429                            queue->grant_tx_handle[pending_idx]);
1430        xenvif_grant_handle_reset(queue, pending_idx);
1431
1432        ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1433                                &queue->mmap_pages[pending_idx], 1);
1434        if (ret) {
1435                netdev_err(queue->vif->dev,
1436                           "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: 0x%x status: %d\n",
1437                           ret,
1438                           pending_idx,
1439                           tx_unmap_op.host_addr,
1440                           tx_unmap_op.handle,
1441                           tx_unmap_op.status);
1442                BUG();
1443        }
1444}
1445
1446static inline int tx_work_todo(struct xenvif_queue *queue)
1447{
1448        if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1449                return 1;
1450
1451        return 0;
1452}
1453
1454static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1455{
1456        return queue->dealloc_cons != queue->dealloc_prod;
1457}
1458
1459void xenvif_unmap_frontend_data_rings(struct xenvif_queue *queue)
1460{
1461        if (queue->tx.sring)
1462                xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1463                                        queue->tx.sring);
1464        if (queue->rx.sring)
1465                xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1466                                        queue->rx.sring);
1467}
1468
1469int xenvif_map_frontend_data_rings(struct xenvif_queue *queue,
1470                                   grant_ref_t tx_ring_ref,
1471                                   grant_ref_t rx_ring_ref)
1472{
1473        void *addr;
1474        struct xen_netif_tx_sring *txs;
1475        struct xen_netif_rx_sring *rxs;
1476        RING_IDX rsp_prod, req_prod;
1477        int err = -ENOMEM;
1478
1479        err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1480                                     &tx_ring_ref, 1, &addr);
1481        if (err)
1482                goto err;
1483
1484        txs = (struct xen_netif_tx_sring *)addr;
1485        rsp_prod = READ_ONCE(txs->rsp_prod);
1486        req_prod = READ_ONCE(txs->req_prod);
1487
1488        BACK_RING_ATTACH(&queue->tx, txs, rsp_prod, XEN_PAGE_SIZE);
1489
1490        err = -EIO;
1491        if (req_prod - rsp_prod > RING_SIZE(&queue->tx))
1492                goto err;
1493
1494        err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1495                                     &rx_ring_ref, 1, &addr);
1496        if (err)
1497                goto err;
1498
1499        rxs = (struct xen_netif_rx_sring *)addr;
1500        rsp_prod = READ_ONCE(rxs->rsp_prod);
1501        req_prod = READ_ONCE(rxs->req_prod);
1502
1503        BACK_RING_ATTACH(&queue->rx, rxs, rsp_prod, XEN_PAGE_SIZE);
1504
1505        err = -EIO;
1506        if (req_prod - rsp_prod > RING_SIZE(&queue->rx))
1507                goto err;
1508
1509        return 0;
1510
1511err:
1512        xenvif_unmap_frontend_data_rings(queue);
1513        return err;
1514}
1515
1516static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
1517{
1518        /* Dealloc thread must remain running until all inflight
1519         * packets complete.
1520         */
1521        return kthread_should_stop() &&
1522                !atomic_read(&queue->inflight_packets);
1523}
1524
1525int xenvif_dealloc_kthread(void *data)
1526{
1527        struct xenvif_queue *queue = data;
1528
1529        for (;;) {
1530                wait_event_interruptible(queue->dealloc_wq,
1531                                         tx_dealloc_work_todo(queue) ||
1532                                         xenvif_dealloc_kthread_should_stop(queue));
1533                if (xenvif_dealloc_kthread_should_stop(queue))
1534                        break;
1535
1536                xenvif_tx_dealloc_action(queue);
1537                cond_resched();
1538        }
1539
1540        /* Unmap anything remaining*/
1541        if (tx_dealloc_work_todo(queue))
1542                xenvif_tx_dealloc_action(queue);
1543
1544        return 0;
1545}
1546
1547static void make_ctrl_response(struct xenvif *vif,
1548                               const struct xen_netif_ctrl_request *req,
1549                               u32 status, u32 data)
1550{
1551        RING_IDX idx = vif->ctrl.rsp_prod_pvt;
1552        struct xen_netif_ctrl_response rsp = {
1553                .id = req->id,
1554                .type = req->type,
1555                .status = status,
1556                .data = data,
1557        };
1558
1559        *RING_GET_RESPONSE(&vif->ctrl, idx) = rsp;
1560        vif->ctrl.rsp_prod_pvt = ++idx;
1561}
1562
1563static void push_ctrl_response(struct xenvif *vif)
1564{
1565        int notify;
1566
1567        RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->ctrl, notify);
1568        if (notify)
1569                notify_remote_via_irq(vif->ctrl_irq);
1570}
1571
1572static void process_ctrl_request(struct xenvif *vif,
1573                                 const struct xen_netif_ctrl_request *req)
1574{
1575        u32 status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED;
1576        u32 data = 0;
1577
1578        switch (req->type) {
1579        case XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM:
1580                status = xenvif_set_hash_alg(vif, req->data[0]);
1581                break;
1582
1583        case XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS:
1584                status = xenvif_get_hash_flags(vif, &data);
1585                break;
1586
1587        case XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS:
1588                status = xenvif_set_hash_flags(vif, req->data[0]);
1589                break;
1590
1591        case XEN_NETIF_CTRL_TYPE_SET_HASH_KEY:
1592                status = xenvif_set_hash_key(vif, req->data[0],
1593                                             req->data[1]);
1594                break;
1595
1596        case XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE:
1597                status = XEN_NETIF_CTRL_STATUS_SUCCESS;
1598                data = XEN_NETBK_MAX_HASH_MAPPING_SIZE;
1599                break;
1600
1601        case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE:
1602                status = xenvif_set_hash_mapping_size(vif,
1603                                                      req->data[0]);
1604                break;
1605
1606        case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING:
1607                status = xenvif_set_hash_mapping(vif, req->data[0],
1608                                                 req->data[1],
1609                                                 req->data[2]);
1610                break;
1611
1612        default:
1613                break;
1614        }
1615
1616        make_ctrl_response(vif, req, status, data);
1617        push_ctrl_response(vif);
1618}
1619
1620static void xenvif_ctrl_action(struct xenvif *vif)
1621{
1622        for (;;) {
1623                RING_IDX req_prod, req_cons;
1624
1625                req_prod = vif->ctrl.sring->req_prod;
1626                req_cons = vif->ctrl.req_cons;
1627
1628                /* Make sure we can see requests before we process them. */
1629                rmb();
1630
1631                if (req_cons == req_prod)
1632                        break;
1633
1634                while (req_cons != req_prod) {
1635                        struct xen_netif_ctrl_request req;
1636
1637                        RING_COPY_REQUEST(&vif->ctrl, req_cons, &req);
1638                        req_cons++;
1639
1640                        process_ctrl_request(vif, &req);
1641                }
1642
1643                vif->ctrl.req_cons = req_cons;
1644                vif->ctrl.sring->req_event = req_cons + 1;
1645        }
1646}
1647
1648static bool xenvif_ctrl_work_todo(struct xenvif *vif)
1649{
1650        if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->ctrl)))
1651                return true;
1652
1653        return false;
1654}
1655
1656irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data)
1657{
1658        struct xenvif *vif = data;
1659        unsigned int eoi_flag = XEN_EOI_FLAG_SPURIOUS;
1660
1661        while (xenvif_ctrl_work_todo(vif)) {
1662                xenvif_ctrl_action(vif);
1663                eoi_flag = 0;
1664        }
1665
1666        xen_irq_lateeoi(irq, eoi_flag);
1667
1668        return IRQ_HANDLED;
1669}
1670
1671static int __init netback_init(void)
1672{
1673        int rc = 0;
1674
1675        if (!xen_domain())
1676                return -ENODEV;
1677
1678        /* Allow as many queues as there are CPUs but max. 8 if user has not
1679         * specified a value.
1680         */
1681        if (xenvif_max_queues == 0)
1682                xenvif_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
1683                                          num_online_cpus());
1684
1685        if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1686                pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1687                        fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1688                fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1689        }
1690
1691        rc = xenvif_xenbus_init();
1692        if (rc)
1693                goto failed_init;
1694
1695#ifdef CONFIG_DEBUG_FS
1696        xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
1697#endif /* CONFIG_DEBUG_FS */
1698
1699        return 0;
1700
1701failed_init:
1702        return rc;
1703}
1704
1705module_init(netback_init);
1706
1707static void __exit netback_fini(void)
1708{
1709#ifdef CONFIG_DEBUG_FS
1710        debugfs_remove_recursive(xen_netback_dbg_root);
1711#endif /* CONFIG_DEBUG_FS */
1712        xenvif_xenbus_fini();
1713}
1714module_exit(netback_fini);
1715
1716MODULE_LICENSE("Dual BSD/GPL");
1717MODULE_ALIAS("xen-backend:vif");
1718