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_ctrl_show(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 DEFINE_SHOW_ATTRIBUTE(xenvif_ctrl);
 198
 199 static void xenvif_debugfs_addif(struct xenvif *vif)
 200 {
 201         struct dentry *pfile;
 202         int i;
 203
 204         if (IS_ERR_OR_NULL(xen_netback_dbg_root))
 205                 return;
 206
 207         vif->xenvif_dbg_root = debugfs_create_dir(vif->dev->name,
 208                                                   xen_netback_dbg_root);
 209         if (!IS_ERR_OR_NULL(vif->xenvif_dbg_root)) {
 210                 for (i = 0; i < vif->num_queues; ++i) {
 211                         char filename[sizeof("io_ring_q") + 4];
 212
 213                         snprintf(filename, sizeof(filename), "io_ring_q%d", i);
 214                         pfile = debugfs_create_file(filename,
 215                                                     0600,
 216                                                     vif->xenvif_dbg_root,
 217                                                     &vif->queues[i],
 218                                                     &xenvif_dbg_io_ring_ops_fops);
 219                         if (IS_ERR_OR_NULL(pfile))
 220                                 pr_warn("Creation of io_ring file returned %ld!\n",
 221                                         PTR_ERR(pfile));
 222                 }
 223
 224                 if (vif->ctrl_irq) {
 225                         pfile = debugfs_create_file("ctrl",
 226                                                     0400,
 227                                                     vif->xenvif_dbg_root,
 228                                                     vif,
 229                                                     &xenvif_ctrl_fops);
 230                         if (IS_ERR_OR_NULL(pfile))
 231                                 pr_warn("Creation of ctrl file returned %ld!\n",
 232                                         PTR_ERR(pfile));
 233                 }
 234         } else
 235                 netdev_warn(vif->dev,
 236                             "Creation of vif debugfs dir returned %ld!\n",
 237                             PTR_ERR(vif->xenvif_dbg_root));
 238 }
 239
 240 static void xenvif_debugfs_delif(struct xenvif *vif)
 241 {
 242         if (IS_ERR_OR_NULL(xen_netback_dbg_root))
 243                 return;
 244
 245         debugfs_remove_recursive(vif->xenvif_dbg_root);
 246         vif->xenvif_dbg_root = NULL;
 247 }
 248 #endif /* CONFIG_DEBUG_FS */
 249
 250 static int netback_remove(struct xenbus_device *dev)
 251 {
 252         struct backend_info *be = dev_get_drvdata(&dev->dev);
 253
 254         set_backend_state(be, XenbusStateClosed);
 255
 256         unregister_hotplug_status_watch(be);
 257         if (be->vif) {
 258                 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
 259                 xen_unregister_watchers(be->vif);
 260                 xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
 261                 xenvif_free(be->vif);
 262                 be->vif = NULL;
 263         }
 264         kfree(be->hotplug_script);
 265         kfree(be);
 266         dev_set_drvdata(&dev->dev, NULL);
 267         return 0;
 268 }
 269
 270
 271 /**
 272  * Entry point to this code when a new device is created.  Allocate the basic
 273  * structures and switch to InitWait.
 274  */
 275 static int netback_probe(struct xenbus_device *dev,
 276                          const struct xenbus_device_id *id)
 277 {
 278         const char *message;
 279         struct xenbus_transaction xbt;
 280         int err;
 281         int sg;
 282         const char *script;
 283         struct backend_info *be = kzalloc(sizeof(struct backend_info),
 284                                           GFP_KERNEL);
 285         if (!be) {
 286                 xenbus_dev_fatal(dev, -ENOMEM,
 287                                  "allocating backend structure");
 288                 return -ENOMEM;
 289         }
 290
 291         be->dev = dev;
 292         dev_set_drvdata(&dev->dev, be);
 293
 294         be->state = XenbusStateInitialising;
 295         err = xenbus_switch_state(dev, XenbusStateInitialising);
 296         if (err)
 297                 goto fail;
 298
 299         sg = 1;
 300
 301         do {
 302                 err = xenbus_transaction_start(&xbt);
 303                 if (err) {
 304                         xenbus_dev_fatal(dev, err, "starting transaction");
 305                         goto fail;
 306                 }
 307
 308                 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", sg);
 309                 if (err) {
 310                         message = "writing feature-sg";
 311                         goto abort_transaction;
 312                 }
 313
 314                 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4",
 315                                     "%d", sg);
 316                 if (err) {
 317                         message = "writing feature-gso-tcpv4";
 318                         goto abort_transaction;
 319                 }
 320
 321                 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv6",
 322                                     "%d", sg);
 323                 if (err) {
 324                         message = "writing feature-gso-tcpv6";
 325                         goto abort_transaction;
 326                 }
 327
 328                 /* We support partial checksum setup for IPv6 packets */
 329                 err = xenbus_printf(xbt, dev->nodename,
 330                                     "feature-ipv6-csum-offload",
 331                                     "%d", 1);
 332                 if (err) {
 333                         message = "writing feature-ipv6-csum-offload";
 334                         goto abort_transaction;
 335                 }
 336
 337                 /* We support rx-copy path. */
 338                 err = xenbus_printf(xbt, dev->nodename,
 339                                     "feature-rx-copy", "%d", 1);
 340                 if (err) {
 341                         message = "writing feature-rx-copy";
 342                         goto abort_transaction;
 343                 }
 344
 345                 /*
 346                  * We don't support rx-flip path (except old guests who don't
 347                  * grok this feature flag).
 348                  */
 349                 err = xenbus_printf(xbt, dev->nodename,
 350                                     "feature-rx-flip", "%d", 0);
 351                 if (err) {
 352                         message = "writing feature-rx-flip";
 353                         goto abort_transaction;
 354                 }
 355
 356                 /* We support dynamic multicast-control. */
 357                 err = xenbus_printf(xbt, dev->nodename,
 358                                     "feature-multicast-control", "%d", 1);
 359                 if (err) {
 360                         message = "writing feature-multicast-control";
 361                         goto abort_transaction;
 362                 }
 363
 364                 err = xenbus_printf(xbt, dev->nodename,
 365                                     "feature-dynamic-multicast-control",
 366                                     "%d", 1);
 367                 if (err) {
 368                         message = "writing feature-dynamic-multicast-control";
 369                         goto abort_transaction;
 370                 }
 371
 372                 err = xenbus_transaction_end(xbt, 0);
 373         } while (err == -EAGAIN);
 374
 375         if (err) {
 376                 xenbus_dev_fatal(dev, err, "completing transaction");
 377                 goto fail;
 378         }
 379
 380         /*
 381          * Split event channels support, this is optional so it is not
 382          * put inside the above loop.
 383          */
 384         err = xenbus_printf(XBT_NIL, dev->nodename,
 385                             "feature-split-event-channels",
 386                             "%u", separate_tx_rx_irq);
 387         if (err)
 388                 pr_debug("Error writing feature-split-event-channels\n");
 389
 390         /* Multi-queue support: This is an optional feature. */
 391         err = xenbus_printf(XBT_NIL, dev->nodename,
 392                             "multi-queue-max-queues", "%u", xenvif_max_queues);
 393         if (err)
 394                 pr_debug("Error writing multi-queue-max-queues\n");
 395
 396         err = xenbus_printf(XBT_NIL, dev->nodename,
 397                             "feature-ctrl-ring",
 398                             "%u", true);
 399         if (err)
 400                 pr_debug("Error writing feature-ctrl-ring\n");
 401
 402         script = xenbus_read(XBT_NIL, dev->nodename, "script", NULL);
 403         if (IS_ERR(script)) {
 404                 err = PTR_ERR(script);
 405                 xenbus_dev_fatal(dev, err, "reading script");
 406                 goto fail;
 407         }
 408
 409         be->hotplug_script = script;
 410
 411
 412         /* This kicks hotplug scripts, so do it immediately. */
 413         err = backend_create_xenvif(be);
 414         if (err)
 415                 goto fail;
 416
 417         return 0;
 418
 419 abort_transaction:
 420         xenbus_transaction_end(xbt, 1);
 421         xenbus_dev_fatal(dev, err, "%s", message);
 422 fail:
 423         pr_debug("failed\n");
 424         netback_remove(dev);
 425         return err;
 426 }
 427
 428
 429 /*
 430  * Handle the creation of the hotplug script environment.  We add the script
 431  * and vif variables to the environment, for the benefit of the vif-* hotplug
 432  * scripts.
 433  */
 434 static int netback_uevent(struct xenbus_device *xdev,
 435                           struct kobj_uevent_env *env)
 436 {
 437         struct backend_info *be = dev_get_drvdata(&xdev->dev);
 438
 439         if (!be)
 440                 return 0;
 441
 442         if (add_uevent_var(env, "script=%s", be->hotplug_script))
 443                 return -ENOMEM;
 444
 445         if (!be->vif)
 446                 return 0;
 447
 448         return add_uevent_var(env, "vif=%s", be->vif->dev->name);
 449 }
 450
 451
 452 static int backend_create_xenvif(struct backend_info *be)
 453 {
 454         int err;
 455         long handle;
 456         struct xenbus_device *dev = be->dev;
 457         struct xenvif *vif;
 458
 459         if (be->vif != NULL)
 460                 return 0;
 461
 462         err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle);
 463         if (err != 1) {
 464                 xenbus_dev_fatal(dev, err, "reading handle");
 465                 return (err < 0) ? err : -EINVAL;
 466         }
 467
 468         vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle);
 469         if (IS_ERR(vif)) {
 470                 err = PTR_ERR(vif);
 471                 xenbus_dev_fatal(dev, err, "creating interface");
 472                 return err;
 473         }
 474         be->vif = vif;
 475
 476         kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE);
 477         return 0;
 478 }
 479
 480 static void backend_disconnect(struct backend_info *be)
 481 {
 482         struct xenvif *vif = be->vif;
 483
 484         if (vif) {
 485                 unsigned int num_queues = vif->num_queues;
 486                 unsigned int queue_index;
 487
 488                 xen_unregister_watchers(vif);
 489 #ifdef CONFIG_DEBUG_FS
 490                 xenvif_debugfs_delif(vif);
 491 #endif /* CONFIG_DEBUG_FS */
 492                 xenvif_disconnect_data(vif);
 493
 494                 /* At this point some of the handlers may still be active
 495                  * so we need to have additional synchronization here.
 496                  */
 497                 vif->num_queues = 0;
 498                 synchronize_net();
 499
 500                 for (queue_index = 0; queue_index < num_queues; ++queue_index)
 501                         xenvif_deinit_queue(&vif->queues[queue_index]);
 502
 503                 vfree(vif->queues);
 504                 vif->queues = NULL;
 505
 506                 xenvif_disconnect_ctrl(vif);
 507         }
 508 }
 509
 510 static void backend_connect(struct backend_info *be)
 511 {
 512         if (be->vif)
 513                 connect(be);
 514 }
 515
 516 static inline void backend_switch_state(struct backend_info *be,
 517                                         enum xenbus_state state)
 518 {
 519         struct xenbus_device *dev = be->dev;
 520
 521         pr_debug("%s -> %s\n", dev->nodename, xenbus_strstate(state));
 522         be->state = state;
 523
 524         /* If we are waiting for a hotplug script then defer the
 525          * actual xenbus state change.
 526          */
 527         if (!be->have_hotplug_status_watch)
 528                 xenbus_switch_state(dev, state);
 529 }
 530
 531 /* Handle backend state transitions:
 532  *
 533  * The backend state starts in Initialising and the following transitions are
 534  * allowed.
 535  *
 536  * Initialising -> InitWait -> Connected
 537  *          \
 538  *           \        ^    \         |
 539  *            \       |     \        |
 540  *             \      |      \       |
 541  *              \     |       \      |
 542  *               \    |        \     |
 543  *                \   |         \    |
 544  *                 V  |          V   V
 545  *
 546  *                  Closed  <-> Closing
 547  *
 548  * The state argument specifies the eventual state of the backend and the
 549  * function transitions to that state via the shortest path.
 550  */
 551 static void set_backend_state(struct backend_info *be,
 552                               enum xenbus_state state)
 553 {
 554         while (be->state != state) {
 555                 switch (be->state) {
 556                 case XenbusStateInitialising:
 557                         switch (state) {
 558                         case XenbusStateInitWait:
 559                         case XenbusStateConnected:
 560                         case XenbusStateClosing:
 561                                 backend_switch_state(be, XenbusStateInitWait);
 562                                 break;
 563                         case XenbusStateClosed:
 564                                 backend_switch_state(be, XenbusStateClosed);
 565                                 break;
 566                         default:
 567                                 BUG();
 568                         }
 569                         break;
 570                 case XenbusStateClosed:
 571                         switch (state) {
 572                         case XenbusStateInitWait:
 573                         case XenbusStateConnected:
 574                                 backend_switch_state(be, XenbusStateInitWait);
 575                                 break;
 576                         case XenbusStateClosing:
 577                                 backend_switch_state(be, XenbusStateClosing);
 578                                 break;
 579                         default:
 580                                 BUG();
 581                         }
 582                         break;
 583                 case XenbusStateInitWait:
 584                         switch (state) {
 585                         case XenbusStateConnected:
 586                                 backend_connect(be);
 587                                 backend_switch_state(be, XenbusStateConnected);
 588                                 break;
 589                         case XenbusStateClosing:
 590                         case XenbusStateClosed:
 591                                 backend_switch_state(be, XenbusStateClosing);
 592                                 break;
 593                         default:
 594                                 BUG();
 595                         }
 596                         break;
 597                 case XenbusStateConnected:
 598                         switch (state) {
 599                         case XenbusStateInitWait:
 600                         case XenbusStateClosing:
 601                         case XenbusStateClosed:
 602                                 backend_disconnect(be);
 603                                 backend_switch_state(be, XenbusStateClosing);
 604                                 break;
 605                         default:
 606                                 BUG();
 607                         }
 608                         break;
 609                 case XenbusStateClosing:
 610                         switch (state) {
 611                         case XenbusStateInitWait:
 612                         case XenbusStateConnected:
 613                         case XenbusStateClosed:
 614                                 backend_switch_state(be, XenbusStateClosed);
 615                                 break;
 616                         default:
 617                                 BUG();
 618                         }
 619                         break;
 620                 default:
 621                         BUG();
 622                 }
 623         }
 624 }
 625
 626 /**
 627  * Callback received when the frontend's state changes.
 628  */
 629 static void frontend_changed(struct xenbus_device *dev,
 630                              enum xenbus_state frontend_state)
 631 {
 632         struct backend_info *be = dev_get_drvdata(&dev->dev);
 633
 634         pr_debug("%s -> %s\n", dev->otherend, xenbus_strstate(frontend_state));
 635
 636         be->frontend_state = frontend_state;
 637
 638         switch (frontend_state) {
 639         case XenbusStateInitialising:
 640                 set_backend_state(be, XenbusStateInitWait);
 641                 break;
 642
 643         case XenbusStateInitialised:
 644                 break;
 645
 646         case XenbusStateConnected:
 647                 set_backend_state(be, XenbusStateConnected);
 648                 break;
 649
 650         case XenbusStateClosing:
 651                 set_backend_state(be, XenbusStateClosing);
 652                 break;
 653
 654         case XenbusStateClosed:
 655                 set_backend_state(be, XenbusStateClosed);
 656                 if (xenbus_dev_is_online(dev))
 657                         break;
 658                 /* fall through - if not online */
 659         case XenbusStateUnknown:
 660                 set_backend_state(be, XenbusStateClosed);
 661                 device_unregister(&dev->dev);
 662                 break;
 663
 664         default:
 665                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
 666                                  frontend_state);
 667                 break;
 668         }
 669 }
 670
 671
 672 static void xen_net_read_rate(struct xenbus_device *dev,
 673                               unsigned long *bytes, unsigned long *usec)
 674 {
 675         char *s, *e;
 676         unsigned long b, u;
 677         char *ratestr;
 678
 679         /* Default to unlimited bandwidth. */
 680         *bytes = ~0UL;
 681         *usec = 0;
 682
 683         ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL);
 684         if (IS_ERR(ratestr))
 685                 return;
 686
 687         s = ratestr;
 688         b = simple_strtoul(s, &e, 10);
 689         if ((s == e) || (*e != ','))
 690                 goto fail;
 691
 692         s = e + 1;
 693         u = simple_strtoul(s, &e, 10);
 694         if ((s == e) || (*e != '\0'))
 695                 goto fail;
 696
 697         *bytes = b;
 698         *usec = u;
 699
 700         kfree(ratestr);
 701         return;
 702
 703  fail:
 704         pr_warn("Failed to parse network rate limit. Traffic unlimited.\n");
 705         kfree(ratestr);
 706 }
 707
 708 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
 709 {
 710         char *s, *e, *macstr;
 711         int i;
 712
 713         macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
 714         if (IS_ERR(macstr))
 715                 return PTR_ERR(macstr);
 716
 717         for (i = 0; i < ETH_ALEN; i++) {
 718                 mac[i] = simple_strtoul(s, &e, 16);
 719                 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
 720                         kfree(macstr);
 721                         return -ENOENT;
 722                 }
 723                 s = e+1;
 724         }
 725
 726         kfree(macstr);
 727         return 0;
 728 }
 729
 730 static void xen_net_rate_changed(struct xenbus_watch *watch,
 731                                  const char *path, const char *token)
 732 {
 733         struct xenvif *vif = container_of(watch, struct xenvif, credit_watch);
 734         struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
 735         unsigned long   credit_bytes;
 736         unsigned long   credit_usec;
 737         unsigned int queue_index;
 738
 739         xen_net_read_rate(dev, &credit_bytes, &credit_usec);
 740         for (queue_index = 0; queue_index < vif->num_queues; queue_index++) {
 741                 struct xenvif_queue *queue = &vif->queues[queue_index];
 742
 743                 queue->credit_bytes = credit_bytes;
 744                 queue->credit_usec = credit_usec;
 745                 if (!mod_timer_pending(&queue->credit_timeout, jiffies) &&
 746                         queue->remaining_credit > queue->credit_bytes) {
 747                         queue->remaining_credit = queue->credit_bytes;
 748                 }
 749         }
 750 }
 751
 752 static int xen_register_credit_watch(struct xenbus_device *dev,
 753                                      struct xenvif *vif)
 754 {
 755         int err = 0;
 756         char *node;
 757         unsigned maxlen = strlen(dev->nodename) + sizeof("/rate");
 758
 759         if (vif->credit_watch.node)
 760                 return -EADDRINUSE;
 761
 762         node = kmalloc(maxlen, GFP_KERNEL);
 763         if (!node)
 764                 return -ENOMEM;
 765         snprintf(node, maxlen, "%s/rate", dev->nodename);
 766         vif->credit_watch.node = node;
 767         vif->credit_watch.callback = xen_net_rate_changed;
 768         err = register_xenbus_watch(&vif->credit_watch);
 769         if (err) {
 770                 pr_err("Failed to set watcher %s\n", vif->credit_watch.node);
 771                 kfree(node);
 772                 vif->credit_watch.node = NULL;
 773                 vif->credit_watch.callback = NULL;
 774         }
 775         return err;
 776 }
 777
 778 static void xen_unregister_credit_watch(struct xenvif *vif)
 779 {
 780         if (vif->credit_watch.node) {
 781                 unregister_xenbus_watch(&vif->credit_watch);
 782                 kfree(vif->credit_watch.node);
 783                 vif->credit_watch.node = NULL;
 784         }
 785 }
 786
 787 static void xen_mcast_ctrl_changed(struct xenbus_watch *watch,
 788                                    const char *path, const char *token)
 789 {
 790         struct xenvif *vif = container_of(watch, struct xenvif,
 791                                           mcast_ctrl_watch);
 792         struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
 793
 794         vif->multicast_control = !!xenbus_read_unsigned(dev->otherend,
 795                                         "request-multicast-control", 0);
 796 }
 797
 798 static int xen_register_mcast_ctrl_watch(struct xenbus_device *dev,
 799                                          struct xenvif *vif)
 800 {
 801         int err = 0;
 802         char *node;
 803         unsigned maxlen = strlen(dev->otherend) +
 804                 sizeof("/request-multicast-control");
 805
 806         if (vif->mcast_ctrl_watch.node) {
 807                 pr_err_ratelimited("Watch is already registered\n");
 808                 return -EADDRINUSE;
 809         }
 810
 811         node = kmalloc(maxlen, GFP_KERNEL);
 812         if (!node) {
 813                 pr_err("Failed to allocate memory for watch\n");
 814                 return -ENOMEM;
 815         }
 816         snprintf(node, maxlen, "%s/request-multicast-control",
 817                  dev->otherend);
 818         vif->mcast_ctrl_watch.node = node;
 819         vif->mcast_ctrl_watch.callback = xen_mcast_ctrl_changed;
 820         err = register_xenbus_watch(&vif->mcast_ctrl_watch);
 821         if (err) {
 822                 pr_err("Failed to set watcher %s\n",
 823                        vif->mcast_ctrl_watch.node);
 824                 kfree(node);
 825                 vif->mcast_ctrl_watch.node = NULL;
 826                 vif->mcast_ctrl_watch.callback = NULL;
 827         }
 828         return err;
 829 }
 830
 831 static void xen_unregister_mcast_ctrl_watch(struct xenvif *vif)
 832 {
 833         if (vif->mcast_ctrl_watch.node) {
 834                 unregister_xenbus_watch(&vif->mcast_ctrl_watch);
 835                 kfree(vif->mcast_ctrl_watch.node);
 836                 vif->mcast_ctrl_watch.node = NULL;
 837         }
 838 }
 839
 840 static void xen_register_watchers(struct xenbus_device *dev,
 841                                   struct xenvif *vif)
 842 {
 843         xen_register_credit_watch(dev, vif);
 844         xen_register_mcast_ctrl_watch(dev, vif);
 845 }
 846
 847 static void xen_unregister_watchers(struct xenvif *vif)
 848 {
 849         xen_unregister_mcast_ctrl_watch(vif);
 850         xen_unregister_credit_watch(vif);
 851 }
 852
 853 static void unregister_hotplug_status_watch(struct backend_info *be)
 854 {
 855         if (be->have_hotplug_status_watch) {
 856                 unregister_xenbus_watch(&be->hotplug_status_watch);
 857                 kfree(be->hotplug_status_watch.node);
 858         }
 859         be->have_hotplug_status_watch = 0;
 860 }
 861
 862 static void hotplug_status_changed(struct xenbus_watch *watch,
 863                                    const char *path,
 864                                    const char *token)
 865 {
 866         struct backend_info *be = container_of(watch,
 867                                                struct backend_info,
 868                                                hotplug_status_watch);
 869         char *str;
 870         unsigned int len;
 871
 872         str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len);
 873         if (IS_ERR(str))
 874                 return;
 875         if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) {
 876                 /* Complete any pending state change */
 877                 xenbus_switch_state(be->dev, be->state);
 878
 879                 /* Not interested in this watch anymore. */
 880                 unregister_hotplug_status_watch(be);
 881         }
 882         kfree(str);
 883 }
 884
 885 static int connect_ctrl_ring(struct backend_info *be)
 886 {
 887         struct xenbus_device *dev = be->dev;
 888         struct xenvif *vif = be->vif;
 889         unsigned int val;
 890         grant_ref_t ring_ref;
 891         unsigned int evtchn;
 892         int err;
 893
 894         err = xenbus_scanf(XBT_NIL, dev->otherend,
 895                            "ctrl-ring-ref", "%u", &val);
 896         if (err < 0)
 897                 goto done; /* The frontend does not have a control ring */
 898
 899         ring_ref = val;
 900
 901         err = xenbus_scanf(XBT_NIL, dev->otherend,
 902                            "event-channel-ctrl", "%u", &val);
 903         if (err < 0) {
 904                 xenbus_dev_fatal(dev, err,
 905                                  "reading %s/event-channel-ctrl",
 906                                  dev->otherend);
 907                 goto fail;
 908         }
 909
 910         evtchn = val;
 911
 912         err = xenvif_connect_ctrl(vif, ring_ref, evtchn);
 913         if (err) {
 914                 xenbus_dev_fatal(dev, err,
 915                                  "mapping shared-frame %u port %u",
 916                                  ring_ref, evtchn);
 917                 goto fail;
 918         }
 919
 920 done:
 921         return 0;
 922
 923 fail:
 924         return err;
 925 }
 926
 927 static void connect(struct backend_info *be)
 928 {
 929         int err;
 930         struct xenbus_device *dev = be->dev;
 931         unsigned long credit_bytes, credit_usec;
 932         unsigned int queue_index;
 933         unsigned int requested_num_queues;
 934         struct xenvif_queue *queue;
 935
 936         /* Check whether the frontend requested multiple queues
 937          * and read the number requested.
 938          */
 939         requested_num_queues = xenbus_read_unsigned(dev->otherend,
 940                                         "multi-queue-num-queues", 1);
 941         if (requested_num_queues > xenvif_max_queues) {
 942                 /* buggy or malicious guest */
 943                 xenbus_dev_fatal(dev, -EINVAL,
 944                                  "guest requested %u queues, exceeding the maximum of %u.",
 945                                  requested_num_queues, xenvif_max_queues);
 946                 return;
 947         }
 948
 949         err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
 950         if (err) {
 951                 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
 952                 return;
 953         }
 954
 955         xen_net_read_rate(dev, &credit_bytes, &credit_usec);
 956         xen_unregister_watchers(be->vif);
 957         xen_register_watchers(dev, be->vif);
 958         read_xenbus_vif_flags(be);
 959
 960         err = connect_ctrl_ring(be);
 961         if (err) {
 962                 xenbus_dev_fatal(dev, err, "connecting control ring");
 963                 return;
 964         }
 965
 966         /* Use the number of queues requested by the frontend */
 967         be->vif->queues = vzalloc(array_size(requested_num_queues,
 968                                              sizeof(struct xenvif_queue)));
 969         if (!be->vif->queues) {
 970                 xenbus_dev_fatal(dev, -ENOMEM,
 971                                  "allocating queues");
 972                 return;
 973         }
 974
 975         be->vif->num_queues = requested_num_queues;
 976         be->vif->stalled_queues = requested_num_queues;
 977
 978         for (queue_index = 0; queue_index < requested_num_queues; ++queue_index) {
 979                 queue = &be->vif->queues[queue_index];
 980                 queue->vif = be->vif;
 981                 queue->id = queue_index;
 982                 snprintf(queue->name, sizeof(queue->name), "%s-q%u",
 983                                 be->vif->dev->name, queue->id);
 984
 985                 err = xenvif_init_queue(queue);
 986                 if (err) {
 987                         /* xenvif_init_queue() cleans up after itself on
 988                          * failure, but we need to clean up any previously
 989                          * initialised queues. Set num_queues to i so that
 990                          * earlier queues can be destroyed using the regular
 991                          * disconnect logic.
 992                          */
 993                         be->vif->num_queues = queue_index;
 994                         goto err;
 995                 }
 996
 997                 queue->credit_bytes = credit_bytes;
 998                 queue->remaining_credit = credit_bytes;
 999                 queue->credit_usec = credit_usec;
1000
1001                 err = connect_data_rings(be, queue);
1002                 if (err) {
1003                         /* connect_data_rings() cleans up after itself on
1004                          * failure, but we need to clean up after
1005                          * xenvif_init_queue() here, and also clean up any
1006                          * previously initialised queues.
1007                          */
1008                         xenvif_deinit_queue(queue);
1009                         be->vif->num_queues = queue_index;
1010                         goto err;
1011                 }
1012         }
1013
1014 #ifdef CONFIG_DEBUG_FS
1015         xenvif_debugfs_addif(be->vif);
1016 #endif /* CONFIG_DEBUG_FS */
1017
1018         /* Initialisation completed, tell core driver the number of
1019          * active queues.
1020          */
1021         rtnl_lock();
1022         netif_set_real_num_tx_queues(be->vif->dev, requested_num_queues);
1023         netif_set_real_num_rx_queues(be->vif->dev, requested_num_queues);
1024         rtnl_unlock();
1025
1026         xenvif_carrier_on(be->vif);
1027
1028         unregister_hotplug_status_watch(be);
1029         err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
1030                                    hotplug_status_changed,
1031                                    "%s/%s", dev->nodename, "hotplug-status");
1032         if (!err)
1033                 be->have_hotplug_status_watch = 1;
1034
1035         netif_tx_wake_all_queues(be->vif->dev);
1036
1037         return;
1038
1039 err:
1040         if (be->vif->num_queues > 0)
1041                 xenvif_disconnect_data(be->vif); /* Clean up existing queues */
1042         for (queue_index = 0; queue_index < be->vif->num_queues; ++queue_index)
1043                 xenvif_deinit_queue(&be->vif->queues[queue_index]);
1044         vfree(be->vif->queues);
1045         be->vif->queues = NULL;
1046         be->vif->num_queues = 0;
1047         xenvif_disconnect_ctrl(be->vif);
1048         return;
1049 }
1050
1051
1052 static int connect_data_rings(struct backend_info *be,
1053                               struct xenvif_queue *queue)
1054 {
1055         struct xenbus_device *dev = be->dev;
1056         unsigned int num_queues = queue->vif->num_queues;
1057         unsigned long tx_ring_ref, rx_ring_ref;
1058         unsigned int tx_evtchn, rx_evtchn;
1059         int err;
1060         char *xspath;
1061         size_t xspathsize;
1062         const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */
1063
1064         /* If the frontend requested 1 queue, or we have fallen back
1065          * to single queue due to lack of frontend support for multi-
1066          * queue, expect the remaining XenStore keys in the toplevel
1067          * directory. Otherwise, expect them in a subdirectory called
1068          * queue-N.
1069          */
1070         if (num_queues == 1) {
1071                 xspath = kzalloc(strlen(dev->otherend) + 1, GFP_KERNEL);
1072                 if (!xspath) {
1073                         xenbus_dev_fatal(dev, -ENOMEM,
1074                                          "reading ring references");
1075                         return -ENOMEM;
1076                 }
1077                 strcpy(xspath, dev->otherend);
1078         } else {
1079                 xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
1080                 xspath = kzalloc(xspathsize, GFP_KERNEL);
1081                 if (!xspath) {
1082                         xenbus_dev_fatal(dev, -ENOMEM,
1083                                          "reading ring references");
1084                         return -ENOMEM;
1085                 }
1086                 snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend,
1087                          queue->id);
1088         }
1089
1090         err = xenbus_gather(XBT_NIL, xspath,
1091                             "tx-ring-ref", "%lu", &tx_ring_ref,
1092                             "rx-ring-ref", "%lu", &rx_ring_ref, NULL);
1093         if (err) {
1094                 xenbus_dev_fatal(dev, err,
1095                                  "reading %s/ring-ref",
1096                                  xspath);
1097                 goto err;
1098         }
1099
1100         /* Try split event channels first, then single event channel. */
1101         err = xenbus_gather(XBT_NIL, xspath,
1102                             "event-channel-tx", "%u", &tx_evtchn,
1103                             "event-channel-rx", "%u", &rx_evtchn, NULL);
1104         if (err < 0) {
1105                 err = xenbus_scanf(XBT_NIL, xspath,
1106                                    "event-channel", "%u", &tx_evtchn);
1107                 if (err < 0) {
1108                         xenbus_dev_fatal(dev, err,
1109                                          "reading %s/event-channel(-tx/rx)",
1110                                          xspath);
1111                         goto err;
1112                 }
1113                 rx_evtchn = tx_evtchn;
1114         }
1115
1116         /* Map the shared frame, irq etc. */
1117         err = xenvif_connect_data(queue, tx_ring_ref, rx_ring_ref,
1118                                   tx_evtchn, rx_evtchn);
1119         if (err) {
1120                 xenbus_dev_fatal(dev, err,
1121                                  "mapping shared-frames %lu/%lu port tx %u rx %u",
1122                                  tx_ring_ref, rx_ring_ref,
1123                                  tx_evtchn, rx_evtchn);
1124                 goto err;
1125         }
1126
1127         err = 0;
1128 err: /* Regular return falls through with err == 0 */
1129         kfree(xspath);
1130         return err;
1131 }
1132
1133 static int read_xenbus_vif_flags(struct backend_info *be)
1134 {
1135         struct xenvif *vif = be->vif;
1136         struct xenbus_device *dev = be->dev;
1137         unsigned int rx_copy;
1138         int err;
1139
1140         err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
1141                            &rx_copy);
1142         if (err == -ENOENT) {
1143                 err = 0;
1144                 rx_copy = 0;
1145         }
1146         if (err < 0) {
1147                 xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy",
1148                                  dev->otherend);
1149                 return err;
1150         }
1151         if (!rx_copy)
1152                 return -EOPNOTSUPP;
1153
1154         if (!xenbus_read_unsigned(dev->otherend, "feature-rx-notify", 0)) {
1155                 /* - Reduce drain timeout to poll more frequently for
1156                  *   Rx requests.
1157                  * - Disable Rx stall detection.
1158                  */
1159                 be->vif->drain_timeout = msecs_to_jiffies(30);
1160                 be->vif->stall_timeout = 0;
1161         }
1162
1163         vif->can_sg = !!xenbus_read_unsigned(dev->otherend, "feature-sg", 0);
1164
1165         vif->gso_mask = 0;
1166
1167         if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv4", 0))
1168                 vif->gso_mask |= GSO_BIT(TCPV4);
1169
1170         if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv6", 0))
1171                 vif->gso_mask |= GSO_BIT(TCPV6);
1172
1173         vif->ip_csum = !xenbus_read_unsigned(dev->otherend,
1174                                              "feature-no-csum-offload", 0);
1175
1176         vif->ipv6_csum = !!xenbus_read_unsigned(dev->otherend,
1177                                                 "feature-ipv6-csum-offload", 0);
1178
1179         return 0;
1180 }
1181
1182 static const struct xenbus_device_id netback_ids[] = {
1183         { "vif" },
1184         { "" }
1185 };
1186
1187 static struct xenbus_driver netback_driver = {
1188         .ids = netback_ids,
1189         .probe = netback_probe,
1190         .remove = netback_remove,
1191         .uevent = netback_uevent,
1192         .otherend_changed = frontend_changed,
1193 };
1194
1195 int xenvif_xenbus_init(void)
1196 {
1197         return xenbus_register_backend(&netback_driver);
1198 }
1199
1200 void xenvif_xenbus_fini(void)
1201 {
1202         return xenbus_unregister_driver(&netback_driver);
1203 }