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_io_ring_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_io_ring_open,
 183         .read = seq_read,
 184         .llseek = seq_lseek,
 185         .release = single_release,
 186         .write = xenvif_write_io_ring,
 187 };
 188
 189 static int xenvif_read_ctrl(struct seq_file *m, void *v)
 190 {
 191         struct xenvif *vif = m->private;
 192
 193         xenvif_dump_hash_info(vif, m);
 194
 195         return 0;
 196 }
 197
 198 static int xenvif_ctrl_open(struct inode *inode, struct file *filp)
 199 {
 200         return single_open(filp, xenvif_read_ctrl, inode->i_private);
 201 }
 202
 203 static const struct file_operations xenvif_dbg_ctrl_ops_fops = {
 204         .owner = THIS_MODULE,
 205         .open = xenvif_ctrl_open,
 206         .read = seq_read,
 207         .llseek = seq_lseek,
 208         .release = single_release,
 209 };
 210
 211 static void xenvif_debugfs_addif(struct xenvif *vif)
 212 {
 213         struct dentry *pfile;
 214         int i;
 215
 216         if (IS_ERR_OR_NULL(xen_netback_dbg_root))
 217                 return;
 218
 219         vif->xenvif_dbg_root = debugfs_create_dir(vif->dev->name,
 220                                                   xen_netback_dbg_root);
 221         if (!IS_ERR_OR_NULL(vif->xenvif_dbg_root)) {
 222                 for (i = 0; i < vif->num_queues; ++i) {
 223                         char filename[sizeof("io_ring_q") + 4];
 224
 225                         snprintf(filename, sizeof(filename), "io_ring_q%d", i);
 226                         pfile = debugfs_create_file(filename,
 227                                                     S_IRUSR | S_IWUSR,
 228                                                     vif->xenvif_dbg_root,
 229                                                     &vif->queues[i],
 230                                                     &xenvif_dbg_io_ring_ops_fops);
 231                         if (IS_ERR_OR_NULL(pfile))
 232                                 pr_warn("Creation of io_ring file returned %ld!\n",
 233                                         PTR_ERR(pfile));
 234                 }
 235
 236                 if (vif->ctrl_irq) {
 237                         pfile = debugfs_create_file("ctrl",
 238                                                     S_IRUSR,
 239                                                     vif->xenvif_dbg_root,
 240                                                     vif,
 241                                                     &xenvif_dbg_ctrl_ops_fops);
 242                         if (IS_ERR_OR_NULL(pfile))
 243                                 pr_warn("Creation of ctrl file returned %ld!\n",
 244                                         PTR_ERR(pfile));
 245                 }
 246         } else
 247                 netdev_warn(vif->dev,
 248                             "Creation of vif debugfs dir returned %ld!\n",
 249                             PTR_ERR(vif->xenvif_dbg_root));
 250 }
 251
 252 static void xenvif_debugfs_delif(struct xenvif *vif)
 253 {
 254         if (IS_ERR_OR_NULL(xen_netback_dbg_root))
 255                 return;
 256
 257         if (!IS_ERR_OR_NULL(vif->xenvif_dbg_root))
 258                 debugfs_remove_recursive(vif->xenvif_dbg_root);
 259         vif->xenvif_dbg_root = NULL;
 260 }
 261 #endif /* CONFIG_DEBUG_FS */
 262
 263 static int netback_remove(struct xenbus_device *dev)
 264 {
 265         struct backend_info *be = dev_get_drvdata(&dev->dev);
 266
 267         set_backend_state(be, XenbusStateClosed);
 268
 269         unregister_hotplug_status_watch(be);
 270         if (be->vif) {
 271                 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
 272                 xen_unregister_watchers(be->vif);
 273                 xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
 274                 xenvif_free(be->vif);
 275                 be->vif = NULL;
 276         }
 277         kfree(be->hotplug_script);
 278         kfree(be);
 279         dev_set_drvdata(&dev->dev, NULL);
 280         return 0;
 281 }
 282
 283
 284 /**
 285  * Entry point to this code when a new device is created.  Allocate the basic
 286  * structures and switch to InitWait.
 287  */
 288 static int netback_probe(struct xenbus_device *dev,
 289                          const struct xenbus_device_id *id)
 290 {
 291         const char *message;
 292         struct xenbus_transaction xbt;
 293         int err;
 294         int sg;
 295         const char *script;
 296         struct backend_info *be = kzalloc(sizeof(struct backend_info),
 297                                           GFP_KERNEL);
 298         if (!be) {
 299                 xenbus_dev_fatal(dev, -ENOMEM,
 300                                  "allocating backend structure");
 301                 return -ENOMEM;
 302         }
 303
 304         be->dev = dev;
 305         dev_set_drvdata(&dev->dev, be);
 306
 307         be->state = XenbusStateInitialising;
 308         err = xenbus_switch_state(dev, XenbusStateInitialising);
 309         if (err)
 310                 goto fail;
 311
 312         sg = 1;
 313
 314         do {
 315                 err = xenbus_transaction_start(&xbt);
 316                 if (err) {
 317                         xenbus_dev_fatal(dev, err, "starting transaction");
 318                         goto fail;
 319                 }
 320
 321                 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", sg);
 322                 if (err) {
 323                         message = "writing feature-sg";
 324                         goto abort_transaction;
 325                 }
 326
 327                 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4",
 328                                     "%d", sg);
 329                 if (err) {
 330                         message = "writing feature-gso-tcpv4";
 331                         goto abort_transaction;
 332                 }
 333
 334                 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv6",
 335                                     "%d", sg);
 336                 if (err) {
 337                         message = "writing feature-gso-tcpv6";
 338                         goto abort_transaction;
 339                 }
 340
 341                 /* We support partial checksum setup for IPv6 packets */
 342                 err = xenbus_printf(xbt, dev->nodename,
 343                                     "feature-ipv6-csum-offload",
 344                                     "%d", 1);
 345                 if (err) {
 346                         message = "writing feature-ipv6-csum-offload";
 347                         goto abort_transaction;
 348                 }
 349
 350                 /* We support rx-copy path. */
 351                 err = xenbus_printf(xbt, dev->nodename,
 352                                     "feature-rx-copy", "%d", 1);
 353                 if (err) {
 354                         message = "writing feature-rx-copy";
 355                         goto abort_transaction;
 356                 }
 357
 358                 /*
 359                  * We don't support rx-flip path (except old guests who don't
 360                  * grok this feature flag).
 361                  */
 362                 err = xenbus_printf(xbt, dev->nodename,
 363                                     "feature-rx-flip", "%d", 0);
 364                 if (err) {
 365                         message = "writing feature-rx-flip";
 366                         goto abort_transaction;
 367                 }
 368
 369                 /* We support dynamic multicast-control. */
 370                 err = xenbus_printf(xbt, dev->nodename,
 371                                     "feature-multicast-control", "%d", 1);
 372                 if (err) {
 373                         message = "writing feature-multicast-control";
 374                         goto abort_transaction;
 375                 }
 376
 377                 err = xenbus_printf(xbt, dev->nodename,
 378                                     "feature-dynamic-multicast-control",
 379                                     "%d", 1);
 380                 if (err) {
 381                         message = "writing feature-dynamic-multicast-control";
 382                         goto abort_transaction;
 383                 }
 384
 385                 err = xenbus_transaction_end(xbt, 0);
 386         } while (err == -EAGAIN);
 387
 388         if (err) {
 389                 xenbus_dev_fatal(dev, err, "completing transaction");
 390                 goto fail;
 391         }
 392
 393         /*
 394          * Split event channels support, this is optional so it is not
 395          * put inside the above loop.
 396          */
 397         err = xenbus_printf(XBT_NIL, dev->nodename,
 398                             "feature-split-event-channels",
 399                             "%u", separate_tx_rx_irq);
 400         if (err)
 401                 pr_debug("Error writing feature-split-event-channels\n");
 402
 403         /* Multi-queue support: This is an optional feature. */
 404         err = xenbus_printf(XBT_NIL, dev->nodename,
 405                             "multi-queue-max-queues", "%u", xenvif_max_queues);
 406         if (err)
 407                 pr_debug("Error writing multi-queue-max-queues\n");
 408
 409         err = xenbus_printf(XBT_NIL, dev->nodename,
 410                             "feature-ctrl-ring",
 411                             "%u", true);
 412         if (err)
 413                 pr_debug("Error writing feature-ctrl-ring\n");
 414
 415         script = xenbus_read(XBT_NIL, dev->nodename, "script", NULL);
 416         if (IS_ERR(script)) {
 417                 err = PTR_ERR(script);
 418                 xenbus_dev_fatal(dev, err, "reading script");
 419                 goto fail;
 420         }
 421
 422         be->hotplug_script = script;
 423
 424
 425         /* This kicks hotplug scripts, so do it immediately. */
 426         err = backend_create_xenvif(be);
 427         if (err)
 428                 goto fail;
 429
 430         return 0;
 431
 432 abort_transaction:
 433         xenbus_transaction_end(xbt, 1);
 434         xenbus_dev_fatal(dev, err, "%s", message);
 435 fail:
 436         pr_debug("failed\n");
 437         netback_remove(dev);
 438         return err;
 439 }
 440
 441
 442 /*
 443  * Handle the creation of the hotplug script environment.  We add the script
 444  * and vif variables to the environment, for the benefit of the vif-* hotplug
 445  * scripts.
 446  */
 447 static int netback_uevent(struct xenbus_device *xdev,
 448                           struct kobj_uevent_env *env)
 449 {
 450         struct backend_info *be = dev_get_drvdata(&xdev->dev);
 451
 452         if (!be)
 453                 return 0;
 454
 455         if (add_uevent_var(env, "script=%s", be->hotplug_script))
 456                 return -ENOMEM;
 457
 458         if (!be->vif)
 459                 return 0;
 460
 461         return add_uevent_var(env, "vif=%s", be->vif->dev->name);
 462 }
 463
 464
 465 static int backend_create_xenvif(struct backend_info *be)
 466 {
 467         int err;
 468         long handle;
 469         struct xenbus_device *dev = be->dev;
 470         struct xenvif *vif;
 471
 472         if (be->vif != NULL)
 473                 return 0;
 474
 475         err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle);
 476         if (err != 1) {
 477                 xenbus_dev_fatal(dev, err, "reading handle");
 478                 return (err < 0) ? err : -EINVAL;
 479         }
 480
 481         vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle);
 482         if (IS_ERR(vif)) {
 483                 err = PTR_ERR(vif);
 484                 xenbus_dev_fatal(dev, err, "creating interface");
 485                 return err;
 486         }
 487         be->vif = vif;
 488
 489         kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE);
 490         return 0;
 491 }
 492
 493 static void backend_disconnect(struct backend_info *be)
 494 {
 495         if (be->vif) {
 496                 xen_unregister_watchers(be->vif);
 497 #ifdef CONFIG_DEBUG_FS
 498                 xenvif_debugfs_delif(be->vif);
 499 #endif /* CONFIG_DEBUG_FS */
 500                 xenvif_disconnect_data(be->vif);
 501                 xenvif_disconnect_ctrl(be->vif);
 502         }
 503 }
 504
 505 static void backend_connect(struct backend_info *be)
 506 {
 507         if (be->vif)
 508                 connect(be);
 509 }
 510
 511 static inline void backend_switch_state(struct backend_info *be,
 512                                         enum xenbus_state state)
 513 {
 514         struct xenbus_device *dev = be->dev;
 515
 516         pr_debug("%s -> %s\n", dev->nodename, xenbus_strstate(state));
 517         be->state = state;
 518
 519         /* If we are waiting for a hotplug script then defer the
 520          * actual xenbus state change.
 521          */
 522         if (!be->have_hotplug_status_watch)
 523                 xenbus_switch_state(dev, state);
 524 }
 525
 526 /* Handle backend state transitions:
 527  *
 528  * The backend state starts in Initialising and the following transitions are
 529  * allowed.
 530  *
 531  * Initialising -> InitWait -> Connected
 532  *          \
 533  *           \        ^    \         |
 534  *            \       |     \        |
 535  *             \      |      \       |
 536  *              \     |       \      |
 537  *               \    |        \     |
 538  *                \   |         \    |
 539  *                 V  |          V   V
 540  *
 541  *                  Closed  <-> Closing
 542  *
 543  * The state argument specifies the eventual state of the backend and the
 544  * function transitions to that state via the shortest path.
 545  */
 546 static void set_backend_state(struct backend_info *be,
 547                               enum xenbus_state state)
 548 {
 549         while (be->state != state) {
 550                 switch (be->state) {
 551                 case XenbusStateInitialising:
 552                         switch (state) {
 553                         case XenbusStateInitWait:
 554                         case XenbusStateConnected:
 555                         case XenbusStateClosing:
 556                                 backend_switch_state(be, XenbusStateInitWait);
 557                                 break;
 558                         case XenbusStateClosed:
 559                                 backend_switch_state(be, XenbusStateClosed);
 560                                 break;
 561                         default:
 562                                 BUG();
 563                         }
 564                         break;
 565                 case XenbusStateClosed:
 566                         switch (state) {
 567                         case XenbusStateInitWait:
 568                         case XenbusStateConnected:
 569                                 backend_switch_state(be, XenbusStateInitWait);
 570                                 break;
 571                         case XenbusStateClosing:
 572                                 backend_switch_state(be, XenbusStateClosing);
 573                                 break;
 574                         default:
 575                                 BUG();
 576                         }
 577                         break;
 578                 case XenbusStateInitWait:
 579                         switch (state) {
 580                         case XenbusStateConnected:
 581                                 backend_connect(be);
 582                                 backend_switch_state(be, XenbusStateConnected);
 583                                 break;
 584                         case XenbusStateClosing:
 585                         case XenbusStateClosed:
 586                                 backend_switch_state(be, XenbusStateClosing);
 587                                 break;
 588                         default:
 589                                 BUG();
 590                         }
 591                         break;
 592                 case XenbusStateConnected:
 593                         switch (state) {
 594                         case XenbusStateInitWait:
 595                         case XenbusStateClosing:
 596                         case XenbusStateClosed:
 597                                 backend_disconnect(be);
 598                                 backend_switch_state(be, XenbusStateClosing);
 599                                 break;
 600                         default:
 601                                 BUG();
 602                         }
 603                         break;
 604                 case XenbusStateClosing:
 605                         switch (state) {
 606                         case XenbusStateInitWait:
 607                         case XenbusStateConnected:
 608                         case XenbusStateClosed:
 609                                 backend_switch_state(be, XenbusStateClosed);
 610                                 break;
 611                         default:
 612                                 BUG();
 613                         }
 614                         break;
 615                 default:
 616                         BUG();
 617                 }
 618         }
 619 }
 620
 621 /**
 622  * Callback received when the frontend's state changes.
 623  */
 624 static void frontend_changed(struct xenbus_device *dev,
 625                              enum xenbus_state frontend_state)
 626 {
 627         struct backend_info *be = dev_get_drvdata(&dev->dev);
 628
 629         pr_debug("%s -> %s\n", dev->otherend, xenbus_strstate(frontend_state));
 630
 631         be->frontend_state = frontend_state;
 632
 633         switch (frontend_state) {
 634         case XenbusStateInitialising:
 635                 set_backend_state(be, XenbusStateInitWait);
 636                 break;
 637
 638         case XenbusStateInitialised:
 639                 break;
 640
 641         case XenbusStateConnected:
 642                 set_backend_state(be, XenbusStateConnected);
 643                 break;
 644
 645         case XenbusStateClosing:
 646                 set_backend_state(be, XenbusStateClosing);
 647                 break;
 648
 649         case XenbusStateClosed:
 650                 set_backend_state(be, XenbusStateClosed);
 651                 if (xenbus_dev_is_online(dev))
 652                         break;
 653                 /* fall through if not online */
 654         case XenbusStateUnknown:
 655                 set_backend_state(be, XenbusStateClosed);
 656                 device_unregister(&dev->dev);
 657                 break;
 658
 659         default:
 660                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
 661                                  frontend_state);
 662                 break;
 663         }
 664 }
 665
 666
 667 static void xen_net_read_rate(struct xenbus_device *dev,
 668                               unsigned long *bytes, unsigned long *usec)
 669 {
 670         char *s, *e;
 671         unsigned long b, u;
 672         char *ratestr;
 673
 674         /* Default to unlimited bandwidth. */
 675         *bytes = ~0UL;
 676         *usec = 0;
 677
 678         ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL);
 679         if (IS_ERR(ratestr))
 680                 return;
 681
 682         s = ratestr;
 683         b = simple_strtoul(s, &e, 10);
 684         if ((s == e) || (*e != ','))
 685                 goto fail;
 686
 687         s = e + 1;
 688         u = simple_strtoul(s, &e, 10);
 689         if ((s == e) || (*e != '\0'))
 690                 goto fail;
 691
 692         *bytes = b;
 693         *usec = u;
 694
 695         kfree(ratestr);
 696         return;
 697
 698  fail:
 699         pr_warn("Failed to parse network rate limit. Traffic unlimited.\n");
 700         kfree(ratestr);
 701 }
 702
 703 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
 704 {
 705         char *s, *e, *macstr;
 706         int i;
 707
 708         macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
 709         if (IS_ERR(macstr))
 710                 return PTR_ERR(macstr);
 711
 712         for (i = 0; i < ETH_ALEN; i++) {
 713                 mac[i] = simple_strtoul(s, &e, 16);
 714                 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
 715                         kfree(macstr);
 716                         return -ENOENT;
 717                 }
 718                 s = e+1;
 719         }
 720
 721         kfree(macstr);
 722         return 0;
 723 }
 724
 725 static void xen_net_rate_changed(struct xenbus_watch *watch,
 726                                 const char **vec, unsigned int len)
 727 {
 728         struct xenvif *vif = container_of(watch, struct xenvif, credit_watch);
 729         struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
 730         unsigned long   credit_bytes;
 731         unsigned long   credit_usec;
 732         unsigned int queue_index;
 733
 734         xen_net_read_rate(dev, &credit_bytes, &credit_usec);
 735         for (queue_index = 0; queue_index < vif->num_queues; queue_index++) {
 736                 struct xenvif_queue *queue = &vif->queues[queue_index];
 737
 738                 queue->credit_bytes = credit_bytes;
 739                 queue->credit_usec = credit_usec;
 740                 if (!mod_timer_pending(&queue->credit_timeout, jiffies) &&
 741                         queue->remaining_credit > queue->credit_bytes) {
 742                         queue->remaining_credit = queue->credit_bytes;
 743                 }
 744         }
 745 }
 746
 747 static int xen_register_credit_watch(struct xenbus_device *dev,
 748                                      struct xenvif *vif)
 749 {
 750         int err = 0;
 751         char *node;
 752         unsigned maxlen = strlen(dev->nodename) + sizeof("/rate");
 753
 754         if (vif->credit_watch.node)
 755                 return -EADDRINUSE;
 756
 757         node = kmalloc(maxlen, GFP_KERNEL);
 758         if (!node)
 759                 return -ENOMEM;
 760         snprintf(node, maxlen, "%s/rate", dev->nodename);
 761         vif->credit_watch.node = node;
 762         vif->credit_watch.callback = xen_net_rate_changed;
 763         err = register_xenbus_watch(&vif->credit_watch);
 764         if (err) {
 765                 pr_err("Failed to set watcher %s\n", vif->credit_watch.node);
 766                 kfree(node);
 767                 vif->credit_watch.node = NULL;
 768                 vif->credit_watch.callback = NULL;
 769         }
 770         return err;
 771 }
 772
 773 static void xen_unregister_credit_watch(struct xenvif *vif)
 774 {
 775         if (vif->credit_watch.node) {
 776                 unregister_xenbus_watch(&vif->credit_watch);
 777                 kfree(vif->credit_watch.node);
 778                 vif->credit_watch.node = NULL;
 779         }
 780 }
 781
 782 static void xen_mcast_ctrl_changed(struct xenbus_watch *watch,
 783                                    const char **vec, unsigned int len)
 784 {
 785         struct xenvif *vif = container_of(watch, struct xenvif,
 786                                           mcast_ctrl_watch);
 787         struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
 788
 789         vif->multicast_control = !!xenbus_read_unsigned(dev->otherend,
 790                                         "request-multicast-control", 0);
 791 }
 792
 793 static int xen_register_mcast_ctrl_watch(struct xenbus_device *dev,
 794                                          struct xenvif *vif)
 795 {
 796         int err = 0;
 797         char *node;
 798         unsigned maxlen = strlen(dev->otherend) +
 799                 sizeof("/request-multicast-control");
 800
 801         if (vif->mcast_ctrl_watch.node) {
 802                 pr_err_ratelimited("Watch is already registered\n");
 803                 return -EADDRINUSE;
 804         }
 805
 806         node = kmalloc(maxlen, GFP_KERNEL);
 807         if (!node) {
 808                 pr_err("Failed to allocate memory for watch\n");
 809                 return -ENOMEM;
 810         }
 811         snprintf(node, maxlen, "%s/request-multicast-control",
 812                  dev->otherend);
 813         vif->mcast_ctrl_watch.node = node;
 814         vif->mcast_ctrl_watch.callback = xen_mcast_ctrl_changed;
 815         err = register_xenbus_watch(&vif->mcast_ctrl_watch);
 816         if (err) {
 817                 pr_err("Failed to set watcher %s\n",
 818                        vif->mcast_ctrl_watch.node);
 819                 kfree(node);
 820                 vif->mcast_ctrl_watch.node = NULL;
 821                 vif->mcast_ctrl_watch.callback = NULL;
 822         }
 823         return err;
 824 }
 825
 826 static void xen_unregister_mcast_ctrl_watch(struct xenvif *vif)
 827 {
 828         if (vif->mcast_ctrl_watch.node) {
 829                 unregister_xenbus_watch(&vif->mcast_ctrl_watch);
 830                 kfree(vif->mcast_ctrl_watch.node);
 831                 vif->mcast_ctrl_watch.node = NULL;
 832         }
 833 }
 834
 835 static void xen_register_watchers(struct xenbus_device *dev,
 836                                   struct xenvif *vif)
 837 {
 838         xen_register_credit_watch(dev, vif);
 839         xen_register_mcast_ctrl_watch(dev, vif);
 840 }
 841
 842 static void xen_unregister_watchers(struct xenvif *vif)
 843 {
 844         xen_unregister_mcast_ctrl_watch(vif);
 845         xen_unregister_credit_watch(vif);
 846 }
 847
 848 static void unregister_hotplug_status_watch(struct backend_info *be)
 849 {
 850         if (be->have_hotplug_status_watch) {
 851                 unregister_xenbus_watch(&be->hotplug_status_watch);
 852                 kfree(be->hotplug_status_watch.node);
 853         }
 854         be->have_hotplug_status_watch = 0;
 855 }
 856
 857 static void hotplug_status_changed(struct xenbus_watch *watch,
 858                                    const char **vec,
 859                                    unsigned int vec_size)
 860 {
 861         struct backend_info *be = container_of(watch,
 862                                                struct backend_info,
 863                                                hotplug_status_watch);
 864         char *str;
 865         unsigned int len;
 866
 867         str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len);
 868         if (IS_ERR(str))
 869                 return;
 870         if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) {
 871                 /* Complete any pending state change */
 872                 xenbus_switch_state(be->dev, be->state);
 873
 874                 /* Not interested in this watch anymore. */
 875                 unregister_hotplug_status_watch(be);
 876         }
 877         kfree(str);
 878 }
 879
 880 static int connect_ctrl_ring(struct backend_info *be)
 881 {
 882         struct xenbus_device *dev = be->dev;
 883         struct xenvif *vif = be->vif;
 884         unsigned int val;
 885         grant_ref_t ring_ref;
 886         unsigned int evtchn;
 887         int err;
 888
 889         err = xenbus_scanf(XBT_NIL, dev->otherend,
 890                            "ctrl-ring-ref", "%u", &val);
 891         if (err < 0)
 892                 goto done; /* The frontend does not have a control ring */
 893
 894         ring_ref = val;
 895
 896         err = xenbus_scanf(XBT_NIL, dev->otherend,
 897                            "event-channel-ctrl", "%u", &val);
 898         if (err < 0) {
 899                 xenbus_dev_fatal(dev, err,
 900                                  "reading %s/event-channel-ctrl",
 901                                  dev->otherend);
 902                 goto fail;
 903         }
 904
 905         evtchn = val;
 906
 907         err = xenvif_connect_ctrl(vif, ring_ref, evtchn);
 908         if (err) {
 909                 xenbus_dev_fatal(dev, err,
 910                                  "mapping shared-frame %u port %u",
 911                                  ring_ref, evtchn);
 912                 goto fail;
 913         }
 914
 915 done:
 916         return 0;
 917
 918 fail:
 919         return err;
 920 }
 921
 922 static void connect(struct backend_info *be)
 923 {
 924         int err;
 925         struct xenbus_device *dev = be->dev;
 926         unsigned long credit_bytes, credit_usec;
 927         unsigned int queue_index;
 928         unsigned int requested_num_queues;
 929         struct xenvif_queue *queue;
 930
 931         /* Check whether the frontend requested multiple queues
 932          * and read the number requested.
 933          */
 934         requested_num_queues = xenbus_read_unsigned(dev->otherend,
 935                                         "multi-queue-num-queues", 1);
 936         if (requested_num_queues > xenvif_max_queues) {
 937                 /* buggy or malicious guest */
 938                 xenbus_dev_fatal(dev, -EINVAL,
 939                                  "guest requested %u queues, exceeding the maximum of %u.",
 940                                  requested_num_queues, xenvif_max_queues);
 941                 return;
 942         }
 943
 944         err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
 945         if (err) {
 946                 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
 947                 return;
 948         }
 949
 950         xen_net_read_rate(dev, &credit_bytes, &credit_usec);
 951         xen_unregister_watchers(be->vif);
 952         xen_register_watchers(dev, be->vif);
 953         read_xenbus_vif_flags(be);
 954
 955         err = connect_ctrl_ring(be);
 956         if (err) {
 957                 xenbus_dev_fatal(dev, err, "connecting control ring");
 958                 return;
 959         }
 960
 961         /* Use the number of queues requested by the frontend */
 962         be->vif->queues = vzalloc(requested_num_queues *
 963                                   sizeof(struct xenvif_queue));
 964         if (!be->vif->queues) {
 965                 xenbus_dev_fatal(dev, -ENOMEM,
 966                                  "allocating queues");
 967                 return;
 968         }
 969
 970         be->vif->num_queues = requested_num_queues;
 971         be->vif->stalled_queues = requested_num_queues;
 972
 973         for (queue_index = 0; queue_index < requested_num_queues; ++queue_index) {
 974                 queue = &be->vif->queues[queue_index];
 975                 queue->vif = be->vif;
 976                 queue->id = queue_index;
 977                 snprintf(queue->name, sizeof(queue->name), "%s-q%u",
 978                                 be->vif->dev->name, queue->id);
 979
 980                 err = xenvif_init_queue(queue);
 981                 if (err) {
 982                         /* xenvif_init_queue() cleans up after itself on
 983                          * failure, but we need to clean up any previously
 984                          * initialised queues. Set num_queues to i so that
 985                          * earlier queues can be destroyed using the regular
 986                          * disconnect logic.
 987                          */
 988                         be->vif->num_queues = queue_index;
 989                         goto err;
 990                 }
 991
 992                 queue->credit_bytes = credit_bytes;
 993                 queue->remaining_credit = credit_bytes;
 994                 queue->credit_usec = credit_usec;
 995
 996                 err = connect_data_rings(be, queue);
 997                 if (err) {
 998                         /* connect_data_rings() cleans up after itself on
 999                          * failure, but we need to clean up after
1000                          * xenvif_init_queue() here, and also clean up any
1001                          * previously initialised queues.
1002                          */
1003                         xenvif_deinit_queue(queue);
1004                         be->vif->num_queues = queue_index;
1005                         goto err;
1006                 }
1007         }
1008
1009 #ifdef CONFIG_DEBUG_FS
1010         xenvif_debugfs_addif(be->vif);
1011 #endif /* CONFIG_DEBUG_FS */
1012
1013         /* Initialisation completed, tell core driver the number of
1014          * active queues.
1015          */
1016         rtnl_lock();
1017         netif_set_real_num_tx_queues(be->vif->dev, requested_num_queues);
1018         netif_set_real_num_rx_queues(be->vif->dev, requested_num_queues);
1019         rtnl_unlock();
1020
1021         xenvif_carrier_on(be->vif);
1022
1023         unregister_hotplug_status_watch(be);
1024         err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
1025                                    hotplug_status_changed,
1026                                    "%s/%s", dev->nodename, "hotplug-status");
1027         if (!err)
1028                 be->have_hotplug_status_watch = 1;
1029
1030         netif_tx_wake_all_queues(be->vif->dev);
1031
1032         return;
1033
1034 err:
1035         if (be->vif->num_queues > 0)
1036                 xenvif_disconnect_data(be->vif); /* Clean up existing queues */
1037         vfree(be->vif->queues);
1038         be->vif->queues = NULL;
1039         be->vif->num_queues = 0;
1040         xenvif_disconnect_ctrl(be->vif);
1041         return;
1042 }
1043
1044
1045 static int connect_data_rings(struct backend_info *be,
1046                               struct xenvif_queue *queue)
1047 {
1048         struct xenbus_device *dev = be->dev;
1049         unsigned int num_queues = queue->vif->num_queues;
1050         unsigned long tx_ring_ref, rx_ring_ref;
1051         unsigned int tx_evtchn, rx_evtchn;
1052         int err;
1053         char *xspath;
1054         size_t xspathsize;
1055         const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */
1056
1057         /* If the frontend requested 1 queue, or we have fallen back
1058          * to single queue due to lack of frontend support for multi-
1059          * queue, expect the remaining XenStore keys in the toplevel
1060          * directory. Otherwise, expect them in a subdirectory called
1061          * queue-N.
1062          */
1063         if (num_queues == 1) {
1064                 xspath = kzalloc(strlen(dev->otherend) + 1, GFP_KERNEL);
1065                 if (!xspath) {
1066                         xenbus_dev_fatal(dev, -ENOMEM,
1067                                          "reading ring references");
1068                         return -ENOMEM;
1069                 }
1070                 strcpy(xspath, dev->otherend);
1071         } else {
1072                 xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
1073                 xspath = kzalloc(xspathsize, GFP_KERNEL);
1074                 if (!xspath) {
1075                         xenbus_dev_fatal(dev, -ENOMEM,
1076                                          "reading ring references");
1077                         return -ENOMEM;
1078                 }
1079                 snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend,
1080                          queue->id);
1081         }
1082
1083         err = xenbus_gather(XBT_NIL, xspath,
1084                             "tx-ring-ref", "%lu", &tx_ring_ref,
1085                             "rx-ring-ref", "%lu", &rx_ring_ref, NULL);
1086         if (err) {
1087                 xenbus_dev_fatal(dev, err,
1088                                  "reading %s/ring-ref",
1089                                  xspath);
1090                 goto err;
1091         }
1092
1093         /* Try split event channels first, then single event channel. */
1094         err = xenbus_gather(XBT_NIL, xspath,
1095                             "event-channel-tx", "%u", &tx_evtchn,
1096                             "event-channel-rx", "%u", &rx_evtchn, NULL);
1097         if (err < 0) {
1098                 err = xenbus_scanf(XBT_NIL, xspath,
1099                                    "event-channel", "%u", &tx_evtchn);
1100                 if (err < 0) {
1101                         xenbus_dev_fatal(dev, err,
1102                                          "reading %s/event-channel(-tx/rx)",
1103                                          xspath);
1104                         goto err;
1105                 }
1106                 rx_evtchn = tx_evtchn;
1107         }
1108
1109         /* Map the shared frame, irq etc. */
1110         err = xenvif_connect_data(queue, tx_ring_ref, rx_ring_ref,
1111                                   tx_evtchn, rx_evtchn);
1112         if (err) {
1113                 xenbus_dev_fatal(dev, err,
1114                                  "mapping shared-frames %lu/%lu port tx %u rx %u",
1115                                  tx_ring_ref, rx_ring_ref,
1116                                  tx_evtchn, rx_evtchn);
1117                 goto err;
1118         }
1119
1120         err = 0;
1121 err: /* Regular return falls through with err == 0 */
1122         kfree(xspath);
1123         return err;
1124 }
1125
1126 static int read_xenbus_vif_flags(struct backend_info *be)
1127 {
1128         struct xenvif *vif = be->vif;
1129         struct xenbus_device *dev = be->dev;
1130         unsigned int rx_copy;
1131         int err;
1132
1133         err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
1134                            &rx_copy);
1135         if (err == -ENOENT) {
1136                 err = 0;
1137                 rx_copy = 0;
1138         }
1139         if (err < 0) {
1140                 xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy",
1141                                  dev->otherend);
1142                 return err;
1143         }
1144         if (!rx_copy)
1145                 return -EOPNOTSUPP;
1146
1147         if (!xenbus_read_unsigned(dev->otherend, "feature-rx-notify", 0)) {
1148                 /* - Reduce drain timeout to poll more frequently for
1149                  *   Rx requests.
1150                  * - Disable Rx stall detection.
1151                  */
1152                 be->vif->drain_timeout = msecs_to_jiffies(30);
1153                 be->vif->stall_timeout = 0;
1154         }
1155
1156         vif->can_sg = !!xenbus_read_unsigned(dev->otherend, "feature-sg", 0);
1157
1158         vif->gso_mask = 0;
1159
1160         if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv4", 0))
1161                 vif->gso_mask |= GSO_BIT(TCPV4);
1162
1163         if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv6", 0))
1164                 vif->gso_mask |= GSO_BIT(TCPV6);
1165
1166         vif->ip_csum = !xenbus_read_unsigned(dev->otherend,
1167                                              "feature-no-csum-offload", 0);
1168
1169         vif->ipv6_csum = !!xenbus_read_unsigned(dev->otherend,
1170                                                 "feature-ipv6-csum-offload", 0);
1171
1172         return 0;
1173 }
1174
1175 static const struct xenbus_device_id netback_ids[] = {
1176         { "vif" },
1177         { "" }
1178 };
1179
1180 static struct xenbus_driver netback_driver = {
1181         .ids = netback_ids,
1182         .probe = netback_probe,
1183         .remove = netback_remove,
1184         .uevent = netback_uevent,
1185         .otherend_changed = frontend_changed,
1186 };
1187
1188 int xenvif_xenbus_init(void)
1189 {
1190         return xenbus_register_backend(&netback_driver);
1191 }
1192
1193 void xenvif_xenbus_fini(void)
1194 {
1195         return xenbus_unregister_driver(&netback_driver);
1196 }