drivers/net/xen-netback/xenbus.c

   1 /*
   2  * Xenbus code for netif backend
   3  *
   4  * Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au>
   5  * Copyright (C) 2005 XenSource Ltd
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "common.h"
  22 #include <linux/vmalloc.h>
  23 #include <linux/rtnetlink.h>
  24
  25 struct backend_info {
  26         struct xenbus_device *dev;
  27         struct xenvif *vif;
  28
  29         /* This is the state that will be reflected in xenstore when any
  30          * active hotplug script completes.
  31          */
  32         enum xenbus_state state;
  33
  34         enum xenbus_state frontend_state;
  35         struct xenbus_watch hotplug_status_watch;
  36         u8 have_hotplug_status_watch:1;
  37 };
  38
  39 static int connect_rings(struct backend_info *be, struct xenvif_queue *queue);
  40 static void connect(struct backend_info *be);
  41 static int read_xenbus_vif_flags(struct backend_info *be);
  42 static void backend_create_xenvif(struct backend_info *be);
  43 static void unregister_hotplug_status_watch(struct backend_info *be);
  44 static void set_backend_state(struct backend_info *be,
  45                               enum xenbus_state state);
  46
  47 #ifdef CONFIG_DEBUG_FS
  48 struct dentry *xen_netback_dbg_root = NULL;
  49
  50 static int xenvif_read_io_ring(struct seq_file *m, void *v)
  51 {
  52         struct xenvif_queue *queue = m->private;
  53         struct xen_netif_tx_back_ring *tx_ring = &queue->tx;
  54         struct xen_netif_rx_back_ring *rx_ring = &queue->rx;
  55
  56         if (tx_ring->sring) {
  57                 struct xen_netif_tx_sring *sring = tx_ring->sring;
  58
  59                 seq_printf(m, "Queue %d\nTX: nr_ents %u\n", queue->id,
  60                            tx_ring->nr_ents);
  61                 seq_printf(m, "req prod %u (%d) cons %u (%d) event %u (%d)\n",
  62                            sring->req_prod,
  63                            sring->req_prod - sring->rsp_prod,
  64                            tx_ring->req_cons,
  65                            tx_ring->req_cons - sring->rsp_prod,
  66                            sring->req_event,
  67                            sring->req_event - sring->rsp_prod);
  68                 seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n",
  69                            sring->rsp_prod,
  70                            tx_ring->rsp_prod_pvt,
  71                            tx_ring->rsp_prod_pvt - sring->rsp_prod,
  72                            sring->rsp_event,
  73                            sring->rsp_event - sring->rsp_prod);
  74                 seq_printf(m, "pending prod %u pending cons %u nr_pending_reqs %u\n",
  75                            queue->pending_prod,
  76                            queue->pending_cons,
  77                            nr_pending_reqs(queue));
  78                 seq_printf(m, "dealloc prod %u dealloc cons %u dealloc_queue %u\n\n",
  79                            queue->dealloc_prod,
  80                            queue->dealloc_cons,
  81                            queue->dealloc_prod - queue->dealloc_cons);
  82         }
  83
  84         if (rx_ring->sring) {
  85                 struct xen_netif_rx_sring *sring = rx_ring->sring;
  86
  87                 seq_printf(m, "RX: nr_ents %u\n", rx_ring->nr_ents);
  88                 seq_printf(m, "req prod %u (%d) cons %u (%d) event %u (%d)\n",
  89                            sring->req_prod,
  90                            sring->req_prod - sring->rsp_prod,
  91                            rx_ring->req_cons,
  92                            rx_ring->req_cons - sring->rsp_prod,
  93                            sring->req_event,
  94                            sring->req_event - sring->rsp_prod);
  95                 seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n\n",
  96                            sring->rsp_prod,
  97                            rx_ring->rsp_prod_pvt,
  98                            rx_ring->rsp_prod_pvt - sring->rsp_prod,
  99                            sring->rsp_event,
 100                            sring->rsp_event - sring->rsp_prod);
 101         }
 102
 103         seq_printf(m, "NAPI state: %lx NAPI weight: %d TX queue len %u\n"
 104                    "Credit timer_pending: %d, credit: %lu, usec: %lu\n"
 105                    "remaining: %lu, expires: %lu, now: %lu\n",
 106                    queue->napi.state, queue->napi.weight,
 107                    skb_queue_len(&queue->tx_queue),
 108                    timer_pending(&queue->credit_timeout),
 109                    queue->credit_bytes,
 110                    queue->credit_usec,
 111                    queue->remaining_credit,
 112                    queue->credit_timeout.expires,
 113                    jiffies);
 114
 115         return 0;
 116 }
 117
 118 #define XENVIF_KICK_STR "kick"
 119
 120 static ssize_t
 121 xenvif_write_io_ring(struct file *filp, const char __user *buf, size_t count,
 122                      loff_t *ppos)
 123 {
 124         struct xenvif_queue *queue =
 125                 ((struct seq_file *)filp->private_data)->private;
 126         int len;
 127         char write[sizeof(XENVIF_KICK_STR)];
 128
 129         /* don't allow partial writes and check the length */
 130         if (*ppos != 0)
 131                 return 0;
 132         if (count < sizeof(XENVIF_KICK_STR) - 1)
 133                 return -ENOSPC;
 134
 135         len = simple_write_to_buffer(write,
 136                                      sizeof(write),
 137                                      ppos,
 138                                      buf,
 139                                      count);
 140         if (len < 0)
 141                 return len;
 142
 143         if (!strncmp(write, XENVIF_KICK_STR, sizeof(XENVIF_KICK_STR) - 1))
 144                 xenvif_interrupt(0, (void *)queue);
 145         else {
 146                 pr_warn("Unknown command to io_ring_q%d. Available: kick\n",
 147                         queue->id);
 148                 count = -EINVAL;
 149         }
 150         return count;
 151 }
 152
 153 static int xenvif_dump_open(struct inode *inode, struct file *filp)
 154 {
 155         int ret;
 156         void *queue = NULL;
 157
 158         if (inode->i_private)
 159                 queue = inode->i_private;
 160         ret = single_open(filp, xenvif_read_io_ring, queue);
 161         filp->f_mode |= FMODE_PWRITE;
 162         return ret;
 163 }
 164
 165 static const struct file_operations xenvif_dbg_io_ring_ops_fops = {
 166         .owner = THIS_MODULE,
 167         .open = xenvif_dump_open,
 168         .read = seq_read,
 169         .llseek = seq_lseek,
 170         .release = single_release,
 171         .write = xenvif_write_io_ring,
 172 };
 173
 174 static void xenvif_debugfs_addif(struct xenvif_queue *queue)
 175 {
 176         struct dentry *pfile;
 177         struct xenvif *vif = queue->vif;
 178         int i;
 179
 180         if (IS_ERR_OR_NULL(xen_netback_dbg_root))
 181                 return;
 182
 183         vif->xenvif_dbg_root = debugfs_create_dir(vif->dev->name,
 184                                                   xen_netback_dbg_root);
 185         if (!IS_ERR_OR_NULL(vif->xenvif_dbg_root)) {
 186                 for (i = 0; i < vif->num_queues; ++i) {
 187                         char filename[sizeof("io_ring_q") + 4];
 188
 189                         snprintf(filename, sizeof(filename), "io_ring_q%d", i);
 190                         pfile = debugfs_create_file(filename,
 191                                                     S_IRUSR | S_IWUSR,
 192                                                     vif->xenvif_dbg_root,
 193                                                     &vif->queues[i],
 194                                                     &xenvif_dbg_io_ring_ops_fops);
 195                         if (IS_ERR_OR_NULL(pfile))
 196                                 pr_warn("Creation of io_ring file returned %ld!\n",
 197                                         PTR_ERR(pfile));
 198                 }
 199         } else
 200                 netdev_warn(vif->dev,
 201                             "Creation of vif debugfs dir returned %ld!\n",
 202                             PTR_ERR(vif->xenvif_dbg_root));
 203 }
 204
 205 static void xenvif_debugfs_delif(struct xenvif *vif)
 206 {
 207         if (IS_ERR_OR_NULL(xen_netback_dbg_root))
 208                 return;
 209
 210         if (!IS_ERR_OR_NULL(vif->xenvif_dbg_root))
 211                 debugfs_remove_recursive(vif->xenvif_dbg_root);
 212         vif->xenvif_dbg_root = NULL;
 213 }
 214 #endif /* CONFIG_DEBUG_FS */
 215
 216 static int netback_remove(struct xenbus_device *dev)
 217 {
 218         struct backend_info *be = dev_get_drvdata(&dev->dev);
 219
 220         set_backend_state(be, XenbusStateClosed);
 221
 222         unregister_hotplug_status_watch(be);
 223         if (be->vif) {
 224                 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
 225                 xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
 226                 xenvif_free(be->vif);
 227                 be->vif = NULL;
 228         }
 229         kfree(be);
 230         dev_set_drvdata(&dev->dev, NULL);
 231         return 0;
 232 }
 233
 234
 235 /**
 236  * Entry point to this code when a new device is created.  Allocate the basic
 237  * structures and switch to InitWait.
 238  */
 239 static int netback_probe(struct xenbus_device *dev,
 240                          const struct xenbus_device_id *id)
 241 {
 242         const char *message;
 243         struct xenbus_transaction xbt;
 244         int err;
 245         int sg;
 246         struct backend_info *be = kzalloc(sizeof(struct backend_info),
 247                                           GFP_KERNEL);
 248         if (!be) {
 249                 xenbus_dev_fatal(dev, -ENOMEM,
 250                                  "allocating backend structure");
 251                 return -ENOMEM;
 252         }
 253
 254         be->dev = dev;
 255         dev_set_drvdata(&dev->dev, be);
 256
 257         sg = 1;
 258
 259         do {
 260                 err = xenbus_transaction_start(&xbt);
 261                 if (err) {
 262                         xenbus_dev_fatal(dev, err, "starting transaction");
 263                         goto fail;
 264                 }
 265
 266                 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", sg);
 267                 if (err) {
 268                         message = "writing feature-sg";
 269                         goto abort_transaction;
 270                 }
 271
 272                 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4",
 273                                     "%d", sg);
 274                 if (err) {
 275                         message = "writing feature-gso-tcpv4";
 276                         goto abort_transaction;
 277                 }
 278
 279                 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv6",
 280                                     "%d", sg);
 281                 if (err) {
 282                         message = "writing feature-gso-tcpv6";
 283                         goto abort_transaction;
 284                 }
 285
 286                 /* We support partial checksum setup for IPv6 packets */
 287                 err = xenbus_printf(xbt, dev->nodename,
 288                                     "feature-ipv6-csum-offload",
 289                                     "%d", 1);
 290                 if (err) {
 291                         message = "writing feature-ipv6-csum-offload";
 292                         goto abort_transaction;
 293                 }
 294
 295                 /* We support rx-copy path. */
 296                 err = xenbus_printf(xbt, dev->nodename,
 297                                     "feature-rx-copy", "%d", 1);
 298                 if (err) {
 299                         message = "writing feature-rx-copy";
 300                         goto abort_transaction;
 301                 }
 302
 303                 /*
 304                  * We don't support rx-flip path (except old guests who don't
 305                  * grok this feature flag).
 306                  */
 307                 err = xenbus_printf(xbt, dev->nodename,
 308                                     "feature-rx-flip", "%d", 0);
 309                 if (err) {
 310                         message = "writing feature-rx-flip";
 311                         goto abort_transaction;
 312                 }
 313
 314                 err = xenbus_transaction_end(xbt, 0);
 315         } while (err == -EAGAIN);
 316
 317         if (err) {
 318                 xenbus_dev_fatal(dev, err, "completing transaction");
 319                 goto fail;
 320         }
 321
 322         /*
 323          * Split event channels support, this is optional so it is not
 324          * put inside the above loop.
 325          */
 326         err = xenbus_printf(XBT_NIL, dev->nodename,
 327                             "feature-split-event-channels",
 328                             "%u", separate_tx_rx_irq);
 329         if (err)
 330                 pr_debug("Error writing feature-split-event-channels\n");
 331
 332         /* Multi-queue support: This is an optional feature. */
 333         err = xenbus_printf(XBT_NIL, dev->nodename,
 334                             "multi-queue-max-queues", "%u", xenvif_max_queues);
 335         if (err)
 336                 pr_debug("Error writing multi-queue-max-queues\n");
 337
 338         err = xenbus_switch_state(dev, XenbusStateInitWait);
 339         if (err)
 340                 goto fail;
 341
 342         be->state = XenbusStateInitWait;
 343
 344         /* This kicks hotplug scripts, so do it immediately. */
 345         backend_create_xenvif(be);
 346
 347         return 0;
 348
 349 abort_transaction:
 350         xenbus_transaction_end(xbt, 1);
 351         xenbus_dev_fatal(dev, err, "%s", message);
 352 fail:
 353         pr_debug("failed\n");
 354         netback_remove(dev);
 355         return err;
 356 }
 357
 358
 359 /*
 360  * Handle the creation of the hotplug script environment.  We add the script
 361  * and vif variables to the environment, for the benefit of the vif-* hotplug
 362  * scripts.
 363  */
 364 static int netback_uevent(struct xenbus_device *xdev,
 365                           struct kobj_uevent_env *env)
 366 {
 367         struct backend_info *be = dev_get_drvdata(&xdev->dev);
 368         char *val;
 369
 370         val = xenbus_read(XBT_NIL, xdev->nodename, "script", NULL);
 371         if (IS_ERR(val)) {
 372                 int err = PTR_ERR(val);
 373                 xenbus_dev_fatal(xdev, err, "reading script");
 374                 return err;
 375         } else {
 376                 if (add_uevent_var(env, "script=%s", val)) {
 377                         kfree(val);
 378                         return -ENOMEM;
 379                 }
 380                 kfree(val);
 381         }
 382
 383         if (!be || !be->vif)
 384                 return 0;
 385
 386         return add_uevent_var(env, "vif=%s", be->vif->dev->name);
 387 }
 388
 389
 390 static void backend_create_xenvif(struct backend_info *be)
 391 {
 392         int err;
 393         long handle;
 394         struct xenbus_device *dev = be->dev;
 395
 396         if (be->vif != NULL)
 397                 return;
 398
 399         err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle);
 400         if (err != 1) {
 401                 xenbus_dev_fatal(dev, err, "reading handle");
 402                 return;
 403         }
 404
 405         be->vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle);
 406         if (IS_ERR(be->vif)) {
 407                 err = PTR_ERR(be->vif);
 408                 be->vif = NULL;
 409                 xenbus_dev_fatal(dev, err, "creating interface");
 410                 return;
 411         }
 412
 413         kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE);
 414 }
 415
 416 static void backend_disconnect(struct backend_info *be)
 417 {
 418         if (be->vif) {
 419 #ifdef CONFIG_DEBUG_FS
 420                 xenvif_debugfs_delif(be->vif);
 421 #endif /* CONFIG_DEBUG_FS */
 422                 xenvif_disconnect(be->vif);
 423         }
 424 }
 425
 426 static void backend_connect(struct backend_info *be)
 427 {
 428         if (be->vif)
 429                 connect(be);
 430 }
 431
 432 static inline void backend_switch_state(struct backend_info *be,
 433                                         enum xenbus_state state)
 434 {
 435         struct xenbus_device *dev = be->dev;
 436
 437         pr_debug("%s -> %s\n", dev->nodename, xenbus_strstate(state));
 438         be->state = state;
 439
 440         /* If we are waiting for a hotplug script then defer the
 441          * actual xenbus state change.
 442          */
 443         if (!be->have_hotplug_status_watch)
 444                 xenbus_switch_state(dev, state);
 445 }
 446
 447 /* Handle backend state transitions:
 448  *
 449  * The backend state starts in InitWait and the following transitions are
 450  * allowed.
 451  *
 452  * InitWait -> Connected
 453  *
 454  *    ^    \         |
 455  *    |     \        |
 456  *    |      \       |
 457  *    |       \      |
 458  *    |        \     |
 459  *    |         \    |
 460  *    |          V   V
 461  *
 462  *  Closed  <-> Closing
 463  *
 464  * The state argument specifies the eventual state of the backend and the
 465  * function transitions to that state via the shortest path.
 466  */
 467 static void set_backend_state(struct backend_info *be,
 468                               enum xenbus_state state)
 469 {
 470         while (be->state != state) {
 471                 switch (be->state) {
 472                 case XenbusStateClosed:
 473                         switch (state) {
 474                         case XenbusStateInitWait:
 475                         case XenbusStateConnected:
 476                                 pr_info("%s: prepare for reconnect\n",
 477                                         be->dev->nodename);
 478                                 backend_switch_state(be, XenbusStateInitWait);
 479                                 break;
 480                         case XenbusStateClosing:
 481                                 backend_switch_state(be, XenbusStateClosing);
 482                                 break;
 483                         default:
 484                                 BUG();
 485                         }
 486                         break;
 487                 case XenbusStateInitWait:
 488                         switch (state) {
 489                         case XenbusStateConnected:
 490                                 backend_connect(be);
 491                                 backend_switch_state(be, XenbusStateConnected);
 492                                 break;
 493                         case XenbusStateClosing:
 494                         case XenbusStateClosed:
 495                                 backend_switch_state(be, XenbusStateClosing);
 496                                 break;
 497                         default:
 498                                 BUG();
 499                         }
 500                         break;
 501                 case XenbusStateConnected:
 502                         switch (state) {
 503                         case XenbusStateInitWait:
 504                         case XenbusStateClosing:
 505                         case XenbusStateClosed:
 506                                 backend_disconnect(be);
 507                                 backend_switch_state(be, XenbusStateClosing);
 508                                 break;
 509                         default:
 510                                 BUG();
 511                         }
 512                         break;
 513                 case XenbusStateClosing:
 514                         switch (state) {
 515                         case XenbusStateInitWait:
 516                         case XenbusStateConnected:
 517                         case XenbusStateClosed:
 518                                 backend_switch_state(be, XenbusStateClosed);
 519                                 break;
 520                         default:
 521                                 BUG();
 522                         }
 523                         break;
 524                 default:
 525                         BUG();
 526                 }
 527         }
 528 }
 529
 530 /**
 531  * Callback received when the frontend's state changes.
 532  */
 533 static void frontend_changed(struct xenbus_device *dev,
 534                              enum xenbus_state frontend_state)
 535 {
 536         struct backend_info *be = dev_get_drvdata(&dev->dev);
 537
 538         pr_debug("%s -> %s\n", dev->otherend, xenbus_strstate(frontend_state));
 539
 540         be->frontend_state = frontend_state;
 541
 542         switch (frontend_state) {
 543         case XenbusStateInitialising:
 544                 set_backend_state(be, XenbusStateInitWait);
 545                 break;
 546
 547         case XenbusStateInitialised:
 548                 break;
 549
 550         case XenbusStateConnected:
 551                 set_backend_state(be, XenbusStateConnected);
 552                 break;
 553
 554         case XenbusStateClosing:
 555                 set_backend_state(be, XenbusStateClosing);
 556                 break;
 557
 558         case XenbusStateClosed:
 559                 set_backend_state(be, XenbusStateClosed);
 560                 if (xenbus_dev_is_online(dev))
 561                         break;
 562                 /* fall through if not online */
 563         case XenbusStateUnknown:
 564                 set_backend_state(be, XenbusStateClosed);
 565                 device_unregister(&dev->dev);
 566                 break;
 567
 568         default:
 569                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
 570                                  frontend_state);
 571                 break;
 572         }
 573 }
 574
 575
 576 static void xen_net_read_rate(struct xenbus_device *dev,
 577                               unsigned long *bytes, unsigned long *usec)
 578 {
 579         char *s, *e;
 580         unsigned long b, u;
 581         char *ratestr;
 582
 583         /* Default to unlimited bandwidth. */
 584         *bytes = ~0UL;
 585         *usec = 0;
 586
 587         ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL);
 588         if (IS_ERR(ratestr))
 589                 return;
 590
 591         s = ratestr;
 592         b = simple_strtoul(s, &e, 10);
 593         if ((s == e) || (*e != ','))
 594                 goto fail;
 595
 596         s = e + 1;
 597         u = simple_strtoul(s, &e, 10);
 598         if ((s == e) || (*e != '\0'))
 599                 goto fail;
 600
 601         *bytes = b;
 602         *usec = u;
 603
 604         kfree(ratestr);
 605         return;
 606
 607  fail:
 608         pr_warn("Failed to parse network rate limit. Traffic unlimited.\n");
 609         kfree(ratestr);
 610 }
 611
 612 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
 613 {
 614         char *s, *e, *macstr;
 615         int i;
 616
 617         macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
 618         if (IS_ERR(macstr))
 619                 return PTR_ERR(macstr);
 620
 621         for (i = 0; i < ETH_ALEN; i++) {
 622                 mac[i] = simple_strtoul(s, &e, 16);
 623                 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
 624                         kfree(macstr);
 625                         return -ENOENT;
 626                 }
 627                 s = e+1;
 628         }
 629
 630         kfree(macstr);
 631         return 0;
 632 }
 633
 634 static void unregister_hotplug_status_watch(struct backend_info *be)
 635 {
 636         if (be->have_hotplug_status_watch) {
 637                 unregister_xenbus_watch(&be->hotplug_status_watch);
 638                 kfree(be->hotplug_status_watch.node);
 639         }
 640         be->have_hotplug_status_watch = 0;
 641 }
 642
 643 static void hotplug_status_changed(struct xenbus_watch *watch,
 644                                    const char **vec,
 645                                    unsigned int vec_size)
 646 {
 647         struct backend_info *be = container_of(watch,
 648                                                struct backend_info,
 649                                                hotplug_status_watch);
 650         char *str;
 651         unsigned int len;
 652
 653         str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len);
 654         if (IS_ERR(str))
 655                 return;
 656         if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) {
 657                 /* Complete any pending state change */
 658                 xenbus_switch_state(be->dev, be->state);
 659
 660                 /* Not interested in this watch anymore. */
 661                 unregister_hotplug_status_watch(be);
 662         }
 663         kfree(str);
 664 }
 665
 666 static void connect(struct backend_info *be)
 667 {
 668         int err;
 669         struct xenbus_device *dev = be->dev;
 670         unsigned long credit_bytes, credit_usec;
 671         unsigned int queue_index;
 672         unsigned int requested_num_queues;
 673         struct xenvif_queue *queue;
 674
 675         /* Check whether the frontend requested multiple queues
 676          * and read the number requested.
 677          */
 678         err = xenbus_scanf(XBT_NIL, dev->otherend,
 679                            "multi-queue-num-queues",
 680                            "%u", &requested_num_queues);
 681         if (err < 0) {
 682                 requested_num_queues = 1; /* Fall back to single queue */
 683         } else if (requested_num_queues > xenvif_max_queues) {
 684                 /* buggy or malicious guest */
 685                 xenbus_dev_fatal(dev, err,
 686                                  "guest requested %u queues, exceeding the maximum of %u.",
 687                                  requested_num_queues, xenvif_max_queues);
 688                 return;
 689         }
 690
 691         err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
 692         if (err) {
 693                 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
 694                 return;
 695         }
 696
 697         xen_net_read_rate(dev, &credit_bytes, &credit_usec);
 698         read_xenbus_vif_flags(be);
 699
 700         /* Use the number of queues requested by the frontend */
 701         be->vif->queues = vzalloc(requested_num_queues *
 702                                   sizeof(struct xenvif_queue));
 703         be->vif->num_queues = requested_num_queues;
 704
 705         for (queue_index = 0; queue_index < requested_num_queues; ++queue_index) {
 706                 queue = &be->vif->queues[queue_index];
 707                 queue->vif = be->vif;
 708                 queue->id = queue_index;
 709                 snprintf(queue->name, sizeof(queue->name), "%s-q%u",
 710                                 be->vif->dev->name, queue->id);
 711
 712                 err = xenvif_init_queue(queue);
 713                 if (err) {
 714                         /* xenvif_init_queue() cleans up after itself on
 715                          * failure, but we need to clean up any previously
 716                          * initialised queues. Set num_queues to i so that
 717                          * earlier queues can be destroyed using the regular
 718                          * disconnect logic.
 719                          */
 720                         be->vif->num_queues = queue_index;
 721                         goto err;
 722                 }
 723
 724                 queue->remaining_credit = credit_bytes;
 725
 726                 err = connect_rings(be, queue);
 727                 if (err) {
 728                         /* connect_rings() cleans up after itself on failure,
 729                          * but we need to clean up after xenvif_init_queue() here,
 730                          * and also clean up any previously initialised queues.
 731                          */
 732                         xenvif_deinit_queue(queue);
 733                         be->vif->num_queues = queue_index;
 734                         goto err;
 735                 }
 736 #ifdef CONFIG_DEBUG_FS
 737                 xenvif_debugfs_addif(queue);
 738 #endif /* CONFIG_DEBUG_FS */
 739         }
 740
 741         /* Initialisation completed, tell core driver the number of
 742          * active queues.
 743          */
 744         rtnl_lock();
 745         netif_set_real_num_tx_queues(be->vif->dev, requested_num_queues);
 746         netif_set_real_num_rx_queues(be->vif->dev, requested_num_queues);
 747         rtnl_unlock();
 748
 749         xenvif_carrier_on(be->vif);
 750
 751         unregister_hotplug_status_watch(be);
 752         err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
 753                                    hotplug_status_changed,
 754                                    "%s/%s", dev->nodename, "hotplug-status");
 755         if (!err)
 756                 be->have_hotplug_status_watch = 1;
 757
 758         netif_tx_wake_all_queues(be->vif->dev);
 759
 760         return;
 761
 762 err:
 763         if (be->vif->num_queues > 0)
 764                 xenvif_disconnect(be->vif); /* Clean up existing queues */
 765         vfree(be->vif->queues);
 766         be->vif->queues = NULL;
 767         be->vif->num_queues = 0;
 768         return;
 769 }
 770
 771
 772 static int connect_rings(struct backend_info *be, struct xenvif_queue *queue)
 773 {
 774         struct xenbus_device *dev = be->dev;
 775         unsigned int num_queues = queue->vif->num_queues;
 776         unsigned long tx_ring_ref, rx_ring_ref;
 777         unsigned int tx_evtchn, rx_evtchn;
 778         int err;
 779         char *xspath;
 780         size_t xspathsize;
 781         const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */
 782
 783         /* If the frontend requested 1 queue, or we have fallen back
 784          * to single queue due to lack of frontend support for multi-
 785          * queue, expect the remaining XenStore keys in the toplevel
 786          * directory. Otherwise, expect them in a subdirectory called
 787          * queue-N.
 788          */
 789         if (num_queues == 1) {
 790                 xspath = kzalloc(strlen(dev->otherend) + 1, GFP_KERNEL);
 791                 if (!xspath) {
 792                         xenbus_dev_fatal(dev, -ENOMEM,
 793                                          "reading ring references");
 794                         return -ENOMEM;
 795                 }
 796                 strcpy(xspath, dev->otherend);
 797         } else {
 798                 xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
 799                 xspath = kzalloc(xspathsize, GFP_KERNEL);
 800                 if (!xspath) {
 801                         xenbus_dev_fatal(dev, -ENOMEM,
 802                                          "reading ring references");
 803                         return -ENOMEM;
 804                 }
 805                 snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend,
 806                          queue->id);
 807         }
 808
 809         err = xenbus_gather(XBT_NIL, xspath,
 810                             "tx-ring-ref", "%lu", &tx_ring_ref,
 811                             "rx-ring-ref", "%lu", &rx_ring_ref, NULL);
 812         if (err) {
 813                 xenbus_dev_fatal(dev, err,
 814                                  "reading %s/ring-ref",
 815                                  xspath);
 816                 goto err;
 817         }
 818
 819         /* Try split event channels first, then single event channel. */
 820         err = xenbus_gather(XBT_NIL, xspath,
 821                             "event-channel-tx", "%u", &tx_evtchn,
 822                             "event-channel-rx", "%u", &rx_evtchn, NULL);
 823         if (err < 0) {
 824                 err = xenbus_scanf(XBT_NIL, xspath,
 825                                    "event-channel", "%u", &tx_evtchn);
 826                 if (err < 0) {
 827                         xenbus_dev_fatal(dev, err,
 828                                          "reading %s/event-channel(-tx/rx)",
 829                                          xspath);
 830                         goto err;
 831                 }
 832                 rx_evtchn = tx_evtchn;
 833         }
 834
 835         /* Map the shared frame, irq etc. */
 836         err = xenvif_connect(queue, tx_ring_ref, rx_ring_ref,
 837                              tx_evtchn, rx_evtchn);
 838         if (err) {
 839                 xenbus_dev_fatal(dev, err,
 840                                  "mapping shared-frames %lu/%lu port tx %u rx %u",
 841                                  tx_ring_ref, rx_ring_ref,
 842                                  tx_evtchn, rx_evtchn);
 843                 goto err;
 844         }
 845
 846         err = 0;
 847 err: /* Regular return falls through with err == 0 */
 848         kfree(xspath);
 849         return err;
 850 }
 851
 852 static int read_xenbus_vif_flags(struct backend_info *be)
 853 {
 854         struct xenvif *vif = be->vif;
 855         struct xenbus_device *dev = be->dev;
 856         unsigned int rx_copy;
 857         int err, val;
 858
 859         err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
 860                            &rx_copy);
 861         if (err == -ENOENT) {
 862                 err = 0;
 863                 rx_copy = 0;
 864         }
 865         if (err < 0) {
 866                 xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy",
 867                                  dev->otherend);
 868                 return err;
 869         }
 870         if (!rx_copy)
 871                 return -EOPNOTSUPP;
 872
 873         if (vif->dev->tx_queue_len != 0) {
 874                 if (xenbus_scanf(XBT_NIL, dev->otherend,
 875                                  "feature-rx-notify", "%d", &val) < 0)
 876                         val = 0;
 877                 if (val)
 878                         vif->can_queue = 1;
 879                 else
 880                         /* Must be non-zero for pfifo_fast to work. */
 881                         vif->dev->tx_queue_len = 1;
 882         }
 883
 884         if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg",
 885                          "%d", &val) < 0)
 886                 val = 0;
 887         vif->can_sg = !!val;
 888
 889         vif->gso_mask = 0;
 890         vif->gso_prefix_mask = 0;
 891
 892         if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4",
 893                          "%d", &val) < 0)
 894                 val = 0;
 895         if (val)
 896                 vif->gso_mask |= GSO_BIT(TCPV4);
 897
 898         if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4-prefix",
 899                          "%d", &val) < 0)
 900                 val = 0;
 901         if (val)
 902                 vif->gso_prefix_mask |= GSO_BIT(TCPV4);
 903
 904         if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv6",
 905                          "%d", &val) < 0)
 906                 val = 0;
 907         if (val)
 908                 vif->gso_mask |= GSO_BIT(TCPV6);
 909
 910         if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv6-prefix",
 911                          "%d", &val) < 0)
 912                 val = 0;
 913         if (val)
 914                 vif->gso_prefix_mask |= GSO_BIT(TCPV6);
 915
 916         if (vif->gso_mask & vif->gso_prefix_mask) {
 917                 xenbus_dev_fatal(dev, err,
 918                                  "%s: gso and gso prefix flags are not "
 919                                  "mutually exclusive",
 920                                  dev->otherend);
 921                 return -EOPNOTSUPP;
 922         }
 923
 924         if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload",
 925                          "%d", &val) < 0)
 926                 val = 0;
 927         vif->ip_csum = !val;
 928
 929         if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-ipv6-csum-offload",
 930                          "%d", &val) < 0)
 931                 val = 0;
 932         vif->ipv6_csum = !!val;
 933
 934         return 0;
 935 }
 936
 937
 938 /* ** Driver Registration ** */
 939
 940
 941 static const struct xenbus_device_id netback_ids[] = {
 942         { "vif" },
 943         { "" }
 944 };
 945
 946
 947 static DEFINE_XENBUS_DRIVER(netback, ,
 948         .probe = netback_probe,
 949         .remove = netback_remove,
 950         .uevent = netback_uevent,
 951         .otherend_changed = frontend_changed,
 952 );
 953
 954 int xenvif_xenbus_init(void)
 955 {
 956         return xenbus_register_backend(&netback_driver);
 957 }
 958
 959 void xenvif_xenbus_fini(void)
 960 {
 961         return xenbus_unregister_driver(&netback_driver);
 962 }