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         const char *hotplug_script;
  39 };
  40
  41 static int connect_data_rings(struct backend_info *be,
  42                               struct xenvif_queue *queue);
  43 static void connect(struct backend_info *be);
  44 static int read_xenbus_vif_flags(struct backend_info *be);
  45 static int backend_create_xenvif(struct backend_info *be);
  46 static void unregister_hotplug_status_watch(struct backend_info *be);
  47 static void xen_unregister_watchers(struct xenvif *vif);
  48 static void set_backend_state(struct backend_info *be,
  49                               enum xenbus_state state);
  50
  51 #ifdef CONFIG_DEBUG_FS
  52 struct dentry *xen_netback_dbg_root = NULL;
  53
  54 static int xenvif_read_io_ring(struct seq_file *m, void *v)
  55 {
  56         struct xenvif_queue *queue = m->private;
  57         struct xen_netif_tx_back_ring *tx_ring = &queue->tx;
  58         struct xen_netif_rx_back_ring *rx_ring = &queue->rx;
  59         struct netdev_queue *dev_queue;
  60
  61         if (tx_ring->sring) {
  62                 struct xen_netif_tx_sring *sring = tx_ring->sring;
  63
  64                 seq_printf(m, "Queue %d\nTX: nr_ents %u\n", queue->id,
  65                            tx_ring->nr_ents);
  66                 seq_printf(m, "req prod %u (%d) cons %u (%d) event %u (%d)\n",
  67                            sring->req_prod,
  68                            sring->req_prod - sring->rsp_prod,
  69                            tx_ring->req_cons,
  70                            tx_ring->req_cons - sring->rsp_prod,
  71                            sring->req_event,
  72                            sring->req_event - sring->rsp_prod);
  73                 seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n",
  74                            sring->rsp_prod,
  75                            tx_ring->rsp_prod_pvt,
  76                            tx_ring->rsp_prod_pvt - sring->rsp_prod,
  77                            sring->rsp_event,
  78                            sring->rsp_event - sring->rsp_prod);
  79                 seq_printf(m, "pending prod %u pending cons %u nr_pending_reqs %u\n",
  80                            queue->pending_prod,
  81                            queue->pending_cons,
  82                            nr_pending_reqs(queue));
  83                 seq_printf(m, "dealloc prod %u dealloc cons %u dealloc_queue %u\n\n",
  84                            queue->dealloc_prod,
  85                            queue->dealloc_cons,
  86                            queue->dealloc_prod - queue->dealloc_cons);
  87         }
  88
  89         if (rx_ring->sring) {
  90                 struct xen_netif_rx_sring *sring = rx_ring->sring;
  91
  92                 seq_printf(m, "RX: nr_ents %u\n", rx_ring->nr_ents);
  93                 seq_printf(m, "req prod %u (%d) cons %u (%d) event %u (%d)\n",
  94                            sring->req_prod,
  95                            sring->req_prod - sring->rsp_prod,
  96                            rx_ring->req_cons,
  97                            rx_ring->req_cons - sring->rsp_prod,
  98                            sring->req_event,
  99                            sring->req_event - sring->rsp_prod);
 100                 seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n\n",
 101                            sring->rsp_prod,
 102                            rx_ring->rsp_prod_pvt,
 103                            rx_ring->rsp_prod_pvt - sring->rsp_prod,
 104                            sring->rsp_event,
 105                            sring->rsp_event - sring->rsp_prod);
 106         }
 107
 108         seq_printf(m, "NAPI state: %lx NAPI weight: %d TX queue len %u\n"
 109                    "Credit timer_pending: %d, credit: %lu, usec: %lu\n"
 110                    "remaining: %lu, expires: %lu, now: %lu\n",
 111                    queue->napi.state, queue->napi.weight,
 112                    skb_queue_len(&queue->tx_queue),
 113                    timer_pending(&queue->credit_timeout),
 114                    queue->credit_bytes,
 115                    queue->credit_usec,
 116                    queue->remaining_credit,
 117                    queue->credit_timeout.expires,
 118                    jiffies);
 119
 120         dev_queue = netdev_get_tx_queue(queue->vif->dev, queue->id);
 121
 122         seq_printf(m, "\nRx internal queue: len %u max %u pkts %u %s\n",
 123                    queue->rx_queue_len, queue->rx_queue_max,
 124                    skb_queue_len(&queue->rx_queue),
 125                    netif_tx_queue_stopped(dev_queue) ? "stopped" : "running");
 126
 127         return 0;
 128 }
 129
 130 #define XENVIF_KICK_STR "kick"
 131 #define BUFFER_SIZE     32
 132
 133 static ssize_t
 134 xenvif_write_io_ring(struct file *filp, const char __user *buf, size_t count,
 135                      loff_t *ppos)
 136 {
 137         struct xenvif_queue *queue =
 138                 ((struct seq_file *)filp->private_data)->private;
 139         int len;
 140         char write[BUFFER_SIZE];
 141
 142         /* don't allow partial writes and check the length */
 143         if (*ppos != 0)
 144                 return 0;
 145         if (count >= sizeof(write))
 146                 return -ENOSPC;
 147
 148         len = simple_write_to_buffer(write,
 149                                      sizeof(write) - 1,
 150                                      ppos,
 151                                      buf,
 152                                      count);
 153         if (len < 0)
 154                 return len;
 155
 156         write[len] = '\0';
 157
 158         if (!strncmp(write, XENVIF_KICK_STR, sizeof(XENVIF_KICK_STR) - 1))
 159                 xenvif_interrupt(0, (void *)queue);
 160         else {
 161                 pr_warn("Unknown command to io_ring_q%d. Available: kick\n",
 162                         queue->id);
 163                 count = -EINVAL;
 164         }
 165         return count;
 166 }
 167
 168 static int xenvif_dump_open(struct inode *inode, struct file *filp)
 169 {
 170         int ret;
 171         void *queue = NULL;
 172
 173         if (inode->i_private)
 174                 queue = inode->i_private;
 175         ret = single_open(filp, xenvif_read_io_ring, queue);
 176         filp->f_mode |= FMODE_PWRITE;
 177         return ret;
 178 }
 179
 180 static const struct file_operations xenvif_dbg_io_ring_ops_fops = {
 181         .owner = THIS_MODULE,
 182         .open = xenvif_dump_open,
 183         .read = seq_read,
 184         .llseek = seq_lseek,
 185         .release = single_release,
 186         .write = xenvif_write_io_ring,
 187 };
 188
 189 static void xenvif_debugfs_addif(struct xenvif *vif)
 190 {
 191         struct dentry *pfile;
 192         int i;
 193
 194         if (IS_ERR_OR_NULL(xen_netback_dbg_root))
 195                 return;
 196
 197         vif->xenvif_dbg_root = debugfs_create_dir(vif->dev->name,
 198                                                   xen_netback_dbg_root);
 199         if (!IS_ERR_OR_NULL(vif->xenvif_dbg_root)) {
 200                 for (i = 0; i < vif->num_queues; ++i) {
 201                         char filename[sizeof("io_ring_q") + 4];
 202
 203                         snprintf(filename, sizeof(filename), "io_ring_q%d", i);
 204                         pfile = debugfs_create_file(filename,
 205                                                     S_IRUSR | S_IWUSR,
 206                                                     vif->xenvif_dbg_root,
 207                                                     &vif->queues[i],
 208                                                     &xenvif_dbg_io_ring_ops_fops);
 209                         if (IS_ERR_OR_NULL(pfile))
 210                                 pr_warn("Creation of io_ring file returned %ld!\n",
 211                                         PTR_ERR(pfile));
 212                 }
 213         } else
 214                 netdev_warn(vif->dev,
 215                             "Creation of vif debugfs dir returned %ld!\n",
 216                             PTR_ERR(vif->xenvif_dbg_root));
 217 }
 218
 219 static void xenvif_debugfs_delif(struct xenvif *vif)
 220 {
 221         if (IS_ERR_OR_NULL(xen_netback_dbg_root))
 222                 return;
 223
 224         if (!IS_ERR_OR_NULL(vif->xenvif_dbg_root))
 225                 debugfs_remove_recursive(vif->xenvif_dbg_root);
 226         vif->xenvif_dbg_root = NULL;
 227 }
 228 #endif /* CONFIG_DEBUG_FS */
 229
 230 static int netback_remove(struct xenbus_device *dev)
 231 {
 232         struct backend_info *be = dev_get_drvdata(&dev->dev);
 233
 234         set_backend_state(be, XenbusStateClosed);
 235
 236         unregister_hotplug_status_watch(be);
 237         if (be->vif) {
 238                 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
 239                 xen_unregister_watchers(be->vif);
 240                 xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
 241                 xenvif_free(be->vif);
 242                 be->vif = NULL;
 243         }
 244         kfree(be->hotplug_script);
 245         kfree(be);
 246         dev_set_drvdata(&dev->dev, NULL);
 247         return 0;
 248 }
 249
 250
 251 /**
 252  * Entry point to this code when a new device is created.  Allocate the basic
 253  * structures and switch to InitWait.
 254  */
 255 static int netback_probe(struct xenbus_device *dev,
 256                          const struct xenbus_device_id *id)
 257 {
 258         const char *message;
 259         struct xenbus_transaction xbt;
 260         int err;
 261         int sg;
 262         const char *script;
 263         struct backend_info *be = kzalloc(sizeof(struct backend_info),
 264                                           GFP_KERNEL);
 265         if (!be) {
 266                 xenbus_dev_fatal(dev, -ENOMEM,
 267                                  "allocating backend structure");
 268                 return -ENOMEM;
 269         }
 270
 271         be->dev = dev;
 272         dev_set_drvdata(&dev->dev, be);
 273
 274         be->state = XenbusStateInitialising;
 275         err = xenbus_switch_state(dev, XenbusStateInitialising);
 276         if (err)
 277                 goto fail;
 278
 279         sg = 1;
 280
 281         do {
 282                 err = xenbus_transaction_start(&xbt);
 283                 if (err) {
 284                         xenbus_dev_fatal(dev, err, "starting transaction");
 285                         goto fail;
 286                 }
 287
 288                 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", sg);
 289                 if (err) {
 290                         message = "writing feature-sg";
 291                         goto abort_transaction;
 292                 }
 293
 294                 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4",
 295                                     "%d", sg);
 296                 if (err) {
 297                         message = "writing feature-gso-tcpv4";
 298                         goto abort_transaction;
 299                 }
 300
 301                 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv6",
 302                                     "%d", sg);
 303                 if (err) {
 304                         message = "writing feature-gso-tcpv6";
 305                         goto abort_transaction;
 306                 }
 307
 308                 /* We support partial checksum setup for IPv6 packets */
 309                 err = xenbus_printf(xbt, dev->nodename,
 310                                     "feature-ipv6-csum-offload",
 311                                     "%d", 1);
 312                 if (err) {
 313                         message = "writing feature-ipv6-csum-offload";
 314                         goto abort_transaction;
 315                 }
 316
 317                 /* We support rx-copy path. */
 318                 err = xenbus_printf(xbt, dev->nodename,
 319                                     "feature-rx-copy", "%d", 1);
 320                 if (err) {
 321                         message = "writing feature-rx-copy";
 322                         goto abort_transaction;
 323                 }
 324
 325                 /*
 326                  * We don't support rx-flip path (except old guests who don't
 327                  * grok this feature flag).
 328                  */
 329                 err = xenbus_printf(xbt, dev->nodename,
 330                                     "feature-rx-flip", "%d", 0);
 331                 if (err) {
 332                         message = "writing feature-rx-flip";
 333                         goto abort_transaction;
 334                 }
 335
 336                 /* We support dynamic multicast-control. */
 337                 err = xenbus_printf(xbt, dev->nodename,
 338                                     "feature-multicast-control", "%d", 1);
 339                 if (err) {
 340                         message = "writing feature-multicast-control";
 341                         goto abort_transaction;
 342                 }
 343
 344                 err = xenbus_printf(xbt, dev->nodename,
 345                                     "feature-dynamic-multicast-control",
 346                                     "%d", 1);
 347                 if (err) {
 348                         message = "writing feature-dynamic-multicast-control";
 349                         goto abort_transaction;
 350                 }
 351
 352                 err = xenbus_transaction_end(xbt, 0);
 353         } while (err == -EAGAIN);
 354
 355         if (err) {
 356                 xenbus_dev_fatal(dev, err, "completing transaction");
 357                 goto fail;
 358         }
 359
 360         /*
 361          * Split event channels support, this is optional so it is not
 362          * put inside the above loop.
 363          */
 364         err = xenbus_printf(XBT_NIL, dev->nodename,
 365                             "feature-split-event-channels",
 366                             "%u", separate_tx_rx_irq);
 367         if (err)
 368                 pr_debug("Error writing feature-split-event-channels\n");
 369
 370         /* Multi-queue support: This is an optional feature. */
 371         err = xenbus_printf(XBT_NIL, dev->nodename,
 372                             "multi-queue-max-queues", "%u", xenvif_max_queues);
 373         if (err)
 374                 pr_debug("Error writing multi-queue-max-queues\n");
 375
 376         err = xenbus_printf(XBT_NIL, dev->nodename,
 377                             "feature-ctrl-ring",
 378                             "%u", true);
 379         if (err)
 380                 pr_debug("Error writing feature-ctrl-ring\n");
 381
 382         script = xenbus_read(XBT_NIL, dev->nodename, "script", NULL);
 383         if (IS_ERR(script)) {
 384                 err = PTR_ERR(script);
 385                 xenbus_dev_fatal(dev, err, "reading script");
 386                 goto fail;
 387         }
 388
 389         be->hotplug_script = script;
 390
 391
 392         /* This kicks hotplug scripts, so do it immediately. */
 393         err = backend_create_xenvif(be);
 394         if (err)
 395                 goto fail;
 396
 397         return 0;
 398
 399 abort_transaction:
 400         xenbus_transaction_end(xbt, 1);
 401         xenbus_dev_fatal(dev, err, "%s", message);
 402 fail:
 403         pr_debug("failed\n");
 404         netback_remove(dev);
 405         return err;
 406 }
 407
 408
 409 /*
 410  * Handle the creation of the hotplug script environment.  We add the script
 411  * and vif variables to the environment, for the benefit of the vif-* hotplug
 412  * scripts.
 413  */
 414 static int netback_uevent(struct xenbus_device *xdev,
 415                           struct kobj_uevent_env *env)
 416 {
 417         struct backend_info *be = dev_get_drvdata(&xdev->dev);
 418
 419         if (!be)
 420                 return 0;
 421
 422         if (add_uevent_var(env, "script=%s", be->hotplug_script))
 423                 return -ENOMEM;
 424
 425         if (!be->vif)
 426                 return 0;
 427
 428         return add_uevent_var(env, "vif=%s", be->vif->dev->name);
 429 }
 430
 431
 432 static int backend_create_xenvif(struct backend_info *be)
 433 {
 434         int err;
 435         long handle;
 436         struct xenbus_device *dev = be->dev;
 437         struct xenvif *vif;
 438
 439         if (be->vif != NULL)
 440                 return 0;
 441
 442         err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle);
 443         if (err != 1) {
 444                 xenbus_dev_fatal(dev, err, "reading handle");
 445                 return (err < 0) ? err : -EINVAL;
 446         }
 447
 448         vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle);
 449         if (IS_ERR(vif)) {
 450                 err = PTR_ERR(vif);
 451                 xenbus_dev_fatal(dev, err, "creating interface");
 452                 return err;
 453         }
 454         be->vif = vif;
 455
 456         kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE);
 457         return 0;
 458 }
 459
 460 static void backend_disconnect(struct backend_info *be)
 461 {
 462         if (be->vif) {
 463                 xen_unregister_watchers(be->vif);
 464 #ifdef CONFIG_DEBUG_FS
 465                 xenvif_debugfs_delif(be->vif);
 466 #endif /* CONFIG_DEBUG_FS */
 467                 xenvif_disconnect_data(be->vif);
 468                 xenvif_disconnect_ctrl(be->vif);
 469         }
 470 }
 471
 472 static void backend_connect(struct backend_info *be)
 473 {
 474         if (be->vif)
 475                 connect(be);
 476 }
 477
 478 static inline void backend_switch_state(struct backend_info *be,
 479                                         enum xenbus_state state)
 480 {
 481         struct xenbus_device *dev = be->dev;
 482
 483         pr_debug("%s -> %s\n", dev->nodename, xenbus_strstate(state));
 484         be->state = state;
 485
 486         /* If we are waiting for a hotplug script then defer the
 487          * actual xenbus state change.
 488          */
 489         if (!be->have_hotplug_status_watch)
 490                 xenbus_switch_state(dev, state);
 491 }
 492
 493 /* Handle backend state transitions:
 494  *
 495  * The backend state starts in Initialising and the following transitions are
 496  * allowed.
 497  *
 498  * Initialising -> InitWait -> Connected
 499  *          \
 500  *           \        ^    \         |
 501  *            \       |     \        |
 502  *             \      |      \       |
 503  *              \     |       \      |
 504  *               \    |        \     |
 505  *                \   |         \    |
 506  *                 V  |          V   V
 507  *
 508  *                  Closed  <-> Closing
 509  *
 510  * The state argument specifies the eventual state of the backend and the
 511  * function transitions to that state via the shortest path.
 512  */
 513 static void set_backend_state(struct backend_info *be,
 514                               enum xenbus_state state)
 515 {
 516         while (be->state != state) {
 517                 switch (be->state) {
 518                 case XenbusStateInitialising:
 519                         switch (state) {
 520                         case XenbusStateInitWait:
 521                         case XenbusStateConnected:
 522                         case XenbusStateClosing:
 523                                 backend_switch_state(be, XenbusStateInitWait);
 524                                 break;
 525                         case XenbusStateClosed:
 526                                 backend_switch_state(be, XenbusStateClosed);
 527                                 break;
 528                         default:
 529                                 BUG();
 530                         }
 531                         break;
 532                 case XenbusStateClosed:
 533                         switch (state) {
 534                         case XenbusStateInitWait:
 535                         case XenbusStateConnected:
 536                                 backend_switch_state(be, XenbusStateInitWait);
 537                                 break;
 538                         case XenbusStateClosing:
 539                                 backend_switch_state(be, XenbusStateClosing);
 540                                 break;
 541                         default:
 542                                 BUG();
 543                         }
 544                         break;
 545                 case XenbusStateInitWait:
 546                         switch (state) {
 547                         case XenbusStateConnected:
 548                                 backend_connect(be);
 549                                 backend_switch_state(be, XenbusStateConnected);
 550                                 break;
 551                         case XenbusStateClosing:
 552                         case XenbusStateClosed:
 553                                 backend_switch_state(be, XenbusStateClosing);
 554                                 break;
 555                         default:
 556                                 BUG();
 557                         }
 558                         break;
 559                 case XenbusStateConnected:
 560                         switch (state) {
 561                         case XenbusStateInitWait:
 562                         case XenbusStateClosing:
 563                         case XenbusStateClosed:
 564                                 backend_disconnect(be);
 565                                 backend_switch_state(be, XenbusStateClosing);
 566                                 break;
 567                         default:
 568                                 BUG();
 569                         }
 570                         break;
 571                 case XenbusStateClosing:
 572                         switch (state) {
 573                         case XenbusStateInitWait:
 574                         case XenbusStateConnected:
 575                         case XenbusStateClosed:
 576                                 backend_switch_state(be, XenbusStateClosed);
 577                                 break;
 578                         default:
 579                                 BUG();
 580                         }
 581                         break;
 582                 default:
 583                         BUG();
 584                 }
 585         }
 586 }
 587
 588 /**
 589  * Callback received when the frontend's state changes.
 590  */
 591 static void frontend_changed(struct xenbus_device *dev,
 592                              enum xenbus_state frontend_state)
 593 {
 594         struct backend_info *be = dev_get_drvdata(&dev->dev);
 595
 596         pr_debug("%s -> %s\n", dev->otherend, xenbus_strstate(frontend_state));
 597
 598         be->frontend_state = frontend_state;
 599
 600         switch (frontend_state) {
 601         case XenbusStateInitialising:
 602                 set_backend_state(be, XenbusStateInitWait);
 603                 break;
 604
 605         case XenbusStateInitialised:
 606                 break;
 607
 608         case XenbusStateConnected:
 609                 set_backend_state(be, XenbusStateConnected);
 610                 break;
 611
 612         case XenbusStateClosing:
 613                 set_backend_state(be, XenbusStateClosing);
 614                 break;
 615
 616         case XenbusStateClosed:
 617                 set_backend_state(be, XenbusStateClosed);
 618                 if (xenbus_dev_is_online(dev))
 619                         break;
 620                 /* fall through if not online */
 621         case XenbusStateUnknown:
 622                 set_backend_state(be, XenbusStateClosed);
 623                 device_unregister(&dev->dev);
 624                 break;
 625
 626         default:
 627                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
 628                                  frontend_state);
 629                 break;
 630         }
 631 }
 632
 633
 634 static void xen_net_read_rate(struct xenbus_device *dev,
 635                               unsigned long *bytes, unsigned long *usec)
 636 {
 637         char *s, *e;
 638         unsigned long b, u;
 639         char *ratestr;
 640
 641         /* Default to unlimited bandwidth. */
 642         *bytes = ~0UL;
 643         *usec = 0;
 644
 645         ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL);
 646         if (IS_ERR(ratestr))
 647                 return;
 648
 649         s = ratestr;
 650         b = simple_strtoul(s, &e, 10);
 651         if ((s == e) || (*e != ','))
 652                 goto fail;
 653
 654         s = e + 1;
 655         u = simple_strtoul(s, &e, 10);
 656         if ((s == e) || (*e != '\0'))
 657                 goto fail;
 658
 659         *bytes = b;
 660         *usec = u;
 661
 662         kfree(ratestr);
 663         return;
 664
 665  fail:
 666         pr_warn("Failed to parse network rate limit. Traffic unlimited.\n");
 667         kfree(ratestr);
 668 }
 669
 670 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
 671 {
 672         char *s, *e, *macstr;
 673         int i;
 674
 675         macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
 676         if (IS_ERR(macstr))
 677                 return PTR_ERR(macstr);
 678
 679         for (i = 0; i < ETH_ALEN; i++) {
 680                 mac[i] = simple_strtoul(s, &e, 16);
 681                 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
 682                         kfree(macstr);
 683                         return -ENOENT;
 684                 }
 685                 s = e+1;
 686         }
 687
 688         kfree(macstr);
 689         return 0;
 690 }
 691
 692 static void xen_net_rate_changed(struct xenbus_watch *watch,
 693                                 const char **vec, unsigned int len)
 694 {
 695         struct xenvif *vif = container_of(watch, struct xenvif, credit_watch);
 696         struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
 697         unsigned long   credit_bytes;
 698         unsigned long   credit_usec;
 699         unsigned int queue_index;
 700
 701         xen_net_read_rate(dev, &credit_bytes, &credit_usec);
 702         for (queue_index = 0; queue_index < vif->num_queues; queue_index++) {
 703                 struct xenvif_queue *queue = &vif->queues[queue_index];
 704
 705                 queue->credit_bytes = credit_bytes;
 706                 queue->credit_usec = credit_usec;
 707                 if (!mod_timer_pending(&queue->credit_timeout, jiffies) &&
 708                         queue->remaining_credit > queue->credit_bytes) {
 709                         queue->remaining_credit = queue->credit_bytes;
 710                 }
 711         }
 712 }
 713
 714 static int xen_register_credit_watch(struct xenbus_device *dev,
 715                                      struct xenvif *vif)
 716 {
 717         int err = 0;
 718         char *node;
 719         unsigned maxlen = strlen(dev->nodename) + sizeof("/rate");
 720
 721         if (vif->credit_watch.node)
 722                 return -EADDRINUSE;
 723
 724         node = kmalloc(maxlen, GFP_KERNEL);
 725         if (!node)
 726                 return -ENOMEM;
 727         snprintf(node, maxlen, "%s/rate", dev->nodename);
 728         vif->credit_watch.node = node;
 729         vif->credit_watch.callback = xen_net_rate_changed;
 730         err = register_xenbus_watch(&vif->credit_watch);
 731         if (err) {
 732                 pr_err("Failed to set watcher %s\n", vif->credit_watch.node);
 733                 kfree(node);
 734                 vif->credit_watch.node = NULL;
 735                 vif->credit_watch.callback = NULL;
 736         }
 737         return err;
 738 }
 739
 740 static void xen_unregister_credit_watch(struct xenvif *vif)
 741 {
 742         if (vif->credit_watch.node) {
 743                 unregister_xenbus_watch(&vif->credit_watch);
 744                 kfree(vif->credit_watch.node);
 745                 vif->credit_watch.node = NULL;
 746         }
 747 }
 748
 749 static void xen_mcast_ctrl_changed(struct xenbus_watch *watch,
 750                                    const char **vec, unsigned int len)
 751 {
 752         struct xenvif *vif = container_of(watch, struct xenvif,
 753                                           mcast_ctrl_watch);
 754         struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
 755         int val;
 756
 757         if (xenbus_scanf(XBT_NIL, dev->otherend,
 758                          "request-multicast-control", "%d", &val) < 0)
 759                 val = 0;
 760         vif->multicast_control = !!val;
 761 }
 762
 763 static int xen_register_mcast_ctrl_watch(struct xenbus_device *dev,
 764                                          struct xenvif *vif)
 765 {
 766         int err = 0;
 767         char *node;
 768         unsigned maxlen = strlen(dev->otherend) +
 769                 sizeof("/request-multicast-control");
 770
 771         if (vif->mcast_ctrl_watch.node) {
 772                 pr_err_ratelimited("Watch is already registered\n");
 773                 return -EADDRINUSE;
 774         }
 775
 776         node = kmalloc(maxlen, GFP_KERNEL);
 777         if (!node) {
 778                 pr_err("Failed to allocate memory for watch\n");
 779                 return -ENOMEM;
 780         }
 781         snprintf(node, maxlen, "%s/request-multicast-control",
 782                  dev->otherend);
 783         vif->mcast_ctrl_watch.node = node;
 784         vif->mcast_ctrl_watch.callback = xen_mcast_ctrl_changed;
 785         err = register_xenbus_watch(&vif->mcast_ctrl_watch);
 786         if (err) {
 787                 pr_err("Failed to set watcher %s\n",
 788                        vif->mcast_ctrl_watch.node);
 789                 kfree(node);
 790                 vif->mcast_ctrl_watch.node = NULL;
 791                 vif->mcast_ctrl_watch.callback = NULL;
 792         }
 793         return err;
 794 }
 795
 796 static void xen_unregister_mcast_ctrl_watch(struct xenvif *vif)
 797 {
 798         if (vif->mcast_ctrl_watch.node) {
 799                 unregister_xenbus_watch(&vif->mcast_ctrl_watch);
 800                 kfree(vif->mcast_ctrl_watch.node);
 801                 vif->mcast_ctrl_watch.node = NULL;
 802         }
 803 }
 804
 805 static void xen_register_watchers(struct xenbus_device *dev,
 806                                   struct xenvif *vif)
 807 {
 808         xen_register_credit_watch(dev, vif);
 809         xen_register_mcast_ctrl_watch(dev, vif);
 810 }
 811
 812 static void xen_unregister_watchers(struct xenvif *vif)
 813 {
 814         xen_unregister_mcast_ctrl_watch(vif);
 815         xen_unregister_credit_watch(vif);
 816 }
 817
 818 static void unregister_hotplug_status_watch(struct backend_info *be)
 819 {
 820         if (be->have_hotplug_status_watch) {
 821                 unregister_xenbus_watch(&be->hotplug_status_watch);
 822                 kfree(be->hotplug_status_watch.node);
 823         }
 824         be->have_hotplug_status_watch = 0;
 825 }
 826
 827 static void hotplug_status_changed(struct xenbus_watch *watch,
 828                                    const char **vec,
 829                                    unsigned int vec_size)
 830 {
 831         struct backend_info *be = container_of(watch,
 832                                                struct backend_info,
 833                                                hotplug_status_watch);
 834         char *str;
 835         unsigned int len;
 836
 837         str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len);
 838         if (IS_ERR(str))
 839                 return;
 840         if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) {
 841                 /* Complete any pending state change */
 842                 xenbus_switch_state(be->dev, be->state);
 843
 844                 /* Not interested in this watch anymore. */
 845                 unregister_hotplug_status_watch(be);
 846         }
 847         kfree(str);
 848 }
 849
 850 static int connect_ctrl_ring(struct backend_info *be)
 851 {
 852         struct xenbus_device *dev = be->dev;
 853         struct xenvif *vif = be->vif;
 854         unsigned int val;
 855         grant_ref_t ring_ref;
 856         unsigned int evtchn;
 857         int err;
 858
 859         err = xenbus_gather(XBT_NIL, dev->otherend,
 860                             "ctrl-ring-ref", "%u", &val, NULL);
 861         if (err)
 862                 goto done; /* The frontend does not have a control ring */
 863
 864         ring_ref = val;
 865
 866         err = xenbus_gather(XBT_NIL, dev->otherend,
 867                             "event-channel-ctrl", "%u", &val, NULL);
 868         if (err) {
 869                 xenbus_dev_fatal(dev, err,
 870                                  "reading %s/event-channel-ctrl",
 871                                  dev->otherend);
 872                 goto fail;
 873         }
 874
 875         evtchn = val;
 876
 877         err = xenvif_connect_ctrl(vif, ring_ref, evtchn);
 878         if (err) {
 879                 xenbus_dev_fatal(dev, err,
 880                                  "mapping shared-frame %u port %u",
 881                                  ring_ref, evtchn);
 882                 goto fail;
 883         }
 884
 885 done:
 886         return 0;
 887
 888 fail:
 889         return err;
 890 }
 891
 892 static void connect(struct backend_info *be)
 893 {
 894         int err;
 895         struct xenbus_device *dev = be->dev;
 896         unsigned long credit_bytes, credit_usec;
 897         unsigned int queue_index;
 898         unsigned int requested_num_queues;
 899         struct xenvif_queue *queue;
 900
 901         /* Check whether the frontend requested multiple queues
 902          * and read the number requested.
 903          */
 904         err = xenbus_scanf(XBT_NIL, dev->otherend,
 905                            "multi-queue-num-queues",
 906                            "%u", &requested_num_queues);
 907         if (err < 0) {
 908                 requested_num_queues = 1; /* Fall back to single queue */
 909         } else if (requested_num_queues > xenvif_max_queues) {
 910                 /* buggy or malicious guest */
 911                 xenbus_dev_fatal(dev, err,
 912                                  "guest requested %u queues, exceeding the maximum of %u.",
 913                                  requested_num_queues, xenvif_max_queues);
 914                 return;
 915         }
 916
 917         err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
 918         if (err) {
 919                 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
 920                 return;
 921         }
 922
 923         xen_net_read_rate(dev, &credit_bytes, &credit_usec);
 924         xen_unregister_watchers(be->vif);
 925         xen_register_watchers(dev, be->vif);
 926         read_xenbus_vif_flags(be);
 927
 928         err = connect_ctrl_ring(be);
 929         if (err) {
 930                 xenbus_dev_fatal(dev, err, "connecting control ring");
 931                 return;
 932         }
 933
 934         /* Use the number of queues requested by the frontend */
 935         be->vif->queues = vzalloc(requested_num_queues *
 936                                   sizeof(struct xenvif_queue));
 937         if (!be->vif->queues) {
 938                 xenbus_dev_fatal(dev, -ENOMEM,
 939                                  "allocating queues");
 940                 return;
 941         }
 942
 943         be->vif->num_queues = requested_num_queues;
 944         be->vif->stalled_queues = requested_num_queues;
 945
 946         for (queue_index = 0; queue_index < requested_num_queues; ++queue_index) {
 947                 queue = &be->vif->queues[queue_index];
 948                 queue->vif = be->vif;
 949                 queue->id = queue_index;
 950                 snprintf(queue->name, sizeof(queue->name), "%s-q%u",
 951                                 be->vif->dev->name, queue->id);
 952
 953                 err = xenvif_init_queue(queue);
 954                 if (err) {
 955                         /* xenvif_init_queue() cleans up after itself on
 956                          * failure, but we need to clean up any previously
 957                          * initialised queues. Set num_queues to i so that
 958                          * earlier queues can be destroyed using the regular
 959                          * disconnect logic.
 960                          */
 961                         be->vif->num_queues = queue_index;
 962                         goto err;
 963                 }
 964
 965                 queue->credit_bytes = credit_bytes;
 966                 queue->remaining_credit = credit_bytes;
 967                 queue->credit_usec = credit_usec;
 968
 969                 err = connect_data_rings(be, queue);
 970                 if (err) {
 971                         /* connect_data_rings() cleans up after itself on
 972                          * failure, but we need to clean up after
 973                          * xenvif_init_queue() here, and also clean up any
 974                          * previously initialised queues.
 975                          */
 976                         xenvif_deinit_queue(queue);
 977                         be->vif->num_queues = queue_index;
 978                         goto err;
 979                 }
 980         }
 981
 982 #ifdef CONFIG_DEBUG_FS
 983         xenvif_debugfs_addif(be->vif);
 984 #endif /* CONFIG_DEBUG_FS */
 985
 986         /* Initialisation completed, tell core driver the number of
 987          * active queues.
 988          */
 989         rtnl_lock();
 990         netif_set_real_num_tx_queues(be->vif->dev, requested_num_queues);
 991         netif_set_real_num_rx_queues(be->vif->dev, requested_num_queues);
 992         rtnl_unlock();
 993
 994         xenvif_carrier_on(be->vif);
 995
 996         unregister_hotplug_status_watch(be);
 997         err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
 998                                    hotplug_status_changed,
 999                                    "%s/%s", dev->nodename, "hotplug-status");
1000         if (!err)
1001                 be->have_hotplug_status_watch = 1;
1002
1003         netif_tx_wake_all_queues(be->vif->dev);
1004
1005         return;
1006
1007 err:
1008         if (be->vif->num_queues > 0)
1009                 xenvif_disconnect_data(be->vif); /* Clean up existing queues */
1010         vfree(be->vif->queues);
1011         be->vif->queues = NULL;
1012         be->vif->num_queues = 0;
1013         xenvif_disconnect_ctrl(be->vif);
1014         return;
1015 }
1016
1017
1018 static int connect_data_rings(struct backend_info *be,
1019                               struct xenvif_queue *queue)
1020 {
1021         struct xenbus_device *dev = be->dev;
1022         unsigned int num_queues = queue->vif->num_queues;
1023         unsigned long tx_ring_ref, rx_ring_ref;
1024         unsigned int tx_evtchn, rx_evtchn;
1025         int err;
1026         char *xspath;
1027         size_t xspathsize;
1028         const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */
1029
1030         /* If the frontend requested 1 queue, or we have fallen back
1031          * to single queue due to lack of frontend support for multi-
1032          * queue, expect the remaining XenStore keys in the toplevel
1033          * directory. Otherwise, expect them in a subdirectory called
1034          * queue-N.
1035          */
1036         if (num_queues == 1) {
1037                 xspath = kzalloc(strlen(dev->otherend) + 1, GFP_KERNEL);
1038                 if (!xspath) {
1039                         xenbus_dev_fatal(dev, -ENOMEM,
1040                                          "reading ring references");
1041                         return -ENOMEM;
1042                 }
1043                 strcpy(xspath, dev->otherend);
1044         } else {
1045                 xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
1046                 xspath = kzalloc(xspathsize, GFP_KERNEL);
1047                 if (!xspath) {
1048                         xenbus_dev_fatal(dev, -ENOMEM,
1049                                          "reading ring references");
1050                         return -ENOMEM;
1051                 }
1052                 snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend,
1053                          queue->id);
1054         }
1055
1056         err = xenbus_gather(XBT_NIL, xspath,
1057                             "tx-ring-ref", "%lu", &tx_ring_ref,
1058                             "rx-ring-ref", "%lu", &rx_ring_ref, NULL);
1059         if (err) {
1060                 xenbus_dev_fatal(dev, err,
1061                                  "reading %s/ring-ref",
1062                                  xspath);
1063                 goto err;
1064         }
1065
1066         /* Try split event channels first, then single event channel. */
1067         err = xenbus_gather(XBT_NIL, xspath,
1068                             "event-channel-tx", "%u", &tx_evtchn,
1069                             "event-channel-rx", "%u", &rx_evtchn, NULL);
1070         if (err < 0) {
1071                 err = xenbus_scanf(XBT_NIL, xspath,
1072                                    "event-channel", "%u", &tx_evtchn);
1073                 if (err < 0) {
1074                         xenbus_dev_fatal(dev, err,
1075                                          "reading %s/event-channel(-tx/rx)",
1076                                          xspath);
1077                         goto err;
1078                 }
1079                 rx_evtchn = tx_evtchn;
1080         }
1081
1082         /* Map the shared frame, irq etc. */
1083         err = xenvif_connect_data(queue, tx_ring_ref, rx_ring_ref,
1084                                   tx_evtchn, rx_evtchn);
1085         if (err) {
1086                 xenbus_dev_fatal(dev, err,
1087                                  "mapping shared-frames %lu/%lu port tx %u rx %u",
1088                                  tx_ring_ref, rx_ring_ref,
1089                                  tx_evtchn, rx_evtchn);
1090                 goto err;
1091         }
1092
1093         err = 0;
1094 err: /* Regular return falls through with err == 0 */
1095         kfree(xspath);
1096         return err;
1097 }
1098
1099 static int read_xenbus_vif_flags(struct backend_info *be)
1100 {
1101         struct xenvif *vif = be->vif;
1102         struct xenbus_device *dev = be->dev;
1103         unsigned int rx_copy;
1104         int err, val;
1105
1106         err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
1107                            &rx_copy);
1108         if (err == -ENOENT) {
1109                 err = 0;
1110                 rx_copy = 0;
1111         }
1112         if (err < 0) {
1113                 xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy",
1114                                  dev->otherend);
1115                 return err;
1116         }
1117         if (!rx_copy)
1118                 return -EOPNOTSUPP;
1119
1120         if (xenbus_scanf(XBT_NIL, dev->otherend,
1121                          "feature-rx-notify", "%d", &val) < 0)
1122                 val = 0;
1123         if (!val) {
1124                 /* - Reduce drain timeout to poll more frequently for
1125                  *   Rx requests.
1126                  * - Disable Rx stall detection.
1127                  */
1128                 be->vif->drain_timeout = msecs_to_jiffies(30);
1129                 be->vif->stall_timeout = 0;
1130         }
1131
1132         if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg",
1133                          "%d", &val) < 0)
1134                 val = 0;
1135         vif->can_sg = !!val;
1136
1137         vif->gso_mask = 0;
1138
1139         if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4",
1140                          "%d", &val) < 0)
1141                 val = 0;
1142         if (val)
1143                 vif->gso_mask |= GSO_BIT(TCPV4);
1144
1145         if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv6",
1146                          "%d", &val) < 0)
1147                 val = 0;
1148         if (val)
1149                 vif->gso_mask |= GSO_BIT(TCPV6);
1150
1151         if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload",
1152                          "%d", &val) < 0)
1153                 val = 0;
1154         vif->ip_csum = !val;
1155
1156         if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-ipv6-csum-offload",
1157                          "%d", &val) < 0)
1158                 val = 0;
1159         vif->ipv6_csum = !!val;
1160
1161         return 0;
1162 }
1163
1164 static const struct xenbus_device_id netback_ids[] = {
1165         { "vif" },
1166         { "" }
1167 };
1168
1169 static struct xenbus_driver netback_driver = {
1170         .ids = netback_ids,
1171         .probe = netback_probe,
1172         .remove = netback_remove,
1173         .uevent = netback_uevent,
1174         .otherend_changed = frontend_changed,
1175 };
1176
1177 int xenvif_xenbus_init(void)
1178 {
1179         return xenbus_register_backend(&netback_driver);
1180 }
1181
1182 void xenvif_xenbus_fini(void)
1183 {
1184         return xenbus_unregister_driver(&netback_driver);
1185 }