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
  25struct 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
  41static int connect_data_rings(struct backend_info *be,
  42			      struct xenvif_queue *queue);
  43static void connect(struct backend_info *be);
  44static int read_xenbus_vif_flags(struct backend_info *be);
  45static int backend_create_xenvif(struct backend_info *be);
  46static void unregister_hotplug_status_watch(struct backend_info *be);
  47static void xen_unregister_watchers(struct xenvif *vif);
  48static void set_backend_state(struct backend_info *be,
  49			      enum xenbus_state state);
  50
  51#ifdef CONFIG_DEBUG_FS
  52struct dentry *xen_netback_dbg_root = NULL;
  53
  54static 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
 133static ssize_t
 134xenvif_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
 168static 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
 180static 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
 189static 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
 198static int xenvif_ctrl_open(struct inode *inode, struct file *filp)
 199{
 200	return single_open(filp, xenvif_read_ctrl, inode->i_private);
 201}
 202
 203static 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
 211static 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
 252static 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
 263static 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 */
 288static 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
 432abort_transaction:
 433	xenbus_transaction_end(xbt, 1);
 434	xenbus_dev_fatal(dev, err, "%s", message);
 435fail:
 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 */
 447static 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
 465static 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
 493static void backend_disconnect(struct backend_info *be)
 494{
 495	if (be->vif) {
 496		unsigned int queue_index;
 497
 498		xen_unregister_watchers(be->vif);
 499#ifdef CONFIG_DEBUG_FS
 500		xenvif_debugfs_delif(be->vif);
 501#endif /* CONFIG_DEBUG_FS */
 502		xenvif_disconnect_data(be->vif);
 503		for (queue_index = 0; queue_index < be->vif->num_queues; ++queue_index)
 504			xenvif_deinit_queue(&be->vif->queues[queue_index]);
 505
 506		spin_lock(&be->vif->lock);
 507		vfree(be->vif->queues);
 508		be->vif->num_queues = 0;
 509		be->vif->queues = NULL;
 510		spin_unlock(&be->vif->lock);
 511
 512		xenvif_disconnect_ctrl(be->vif);
 513	}
 514}
 515
 516static void backend_connect(struct backend_info *be)
 517{
 518	if (be->vif)
 519		connect(be);
 520}
 521
 522static inline void backend_switch_state(struct backend_info *be,
 523					enum xenbus_state state)
 524{
 525	struct xenbus_device *dev = be->dev;
 526
 527	pr_debug("%s -> %s\n", dev->nodename, xenbus_strstate(state));
 528	be->state = state;
 529
 530	/* If we are waiting for a hotplug script then defer the
 531	 * actual xenbus state change.
 532	 */
 533	if (!be->have_hotplug_status_watch)
 534		xenbus_switch_state(dev, state);
 535}
 536
 537/* Handle backend state transitions:
 538 *
 539 * The backend state starts in Initialising and the following transitions are
 540 * allowed.
 541 *
 542 * Initialising -> InitWait -> Connected
 543 *          \
 544 *           \        ^    \         |
 545 *            \       |     \        |
 546 *             \      |      \       |
 547 *              \     |       \      |
 548 *               \    |        \     |
 549 *                \   |         \    |
 550 *                 V  |          V   V
 551 *
 552 *                  Closed  <-> Closing
 553 *
 554 * The state argument specifies the eventual state of the backend and the
 555 * function transitions to that state via the shortest path.
 556 */
 557static void set_backend_state(struct backend_info *be,
 558			      enum xenbus_state state)
 559{
 560	while (be->state != state) {
 561		switch (be->state) {
 562		case XenbusStateInitialising:
 563			switch (state) {
 564			case XenbusStateInitWait:
 565			case XenbusStateConnected:
 566			case XenbusStateClosing:
 567				backend_switch_state(be, XenbusStateInitWait);
 568				break;
 569			case XenbusStateClosed:
 570				backend_switch_state(be, XenbusStateClosed);
 571				break;
 572			default:
 573				BUG();
 574			}
 575			break;
 576		case XenbusStateClosed:
 577			switch (state) {
 578			case XenbusStateInitWait:
 579			case XenbusStateConnected:
 580				backend_switch_state(be, XenbusStateInitWait);
 581				break;
 582			case XenbusStateClosing:
 583				backend_switch_state(be, XenbusStateClosing);
 584				break;
 585			default:
 586				BUG();
 587			}
 588			break;
 589		case XenbusStateInitWait:
 590			switch (state) {
 591			case XenbusStateConnected:
 592				backend_connect(be);
 593				backend_switch_state(be, XenbusStateConnected);
 594				break;
 595			case XenbusStateClosing:
 596			case XenbusStateClosed:
 597				backend_switch_state(be, XenbusStateClosing);
 598				break;
 599			default:
 600				BUG();
 601			}
 602			break;
 603		case XenbusStateConnected:
 604			switch (state) {
 605			case XenbusStateInitWait:
 606			case XenbusStateClosing:
 607			case XenbusStateClosed:
 608				backend_disconnect(be);
 609				backend_switch_state(be, XenbusStateClosing);
 610				break;
 611			default:
 612				BUG();
 613			}
 614			break;
 615		case XenbusStateClosing:
 616			switch (state) {
 617			case XenbusStateInitWait:
 618			case XenbusStateConnected:
 619			case XenbusStateClosed:
 620				backend_switch_state(be, XenbusStateClosed);
 621				break;
 622			default:
 623				BUG();
 624			}
 625			break;
 626		default:
 627			BUG();
 628		}
 629	}
 630}
 631
 632/**
 633 * Callback received when the frontend's state changes.
 634 */
 635static void frontend_changed(struct xenbus_device *dev,
 636			     enum xenbus_state frontend_state)
 637{
 638	struct backend_info *be = dev_get_drvdata(&dev->dev);
 639
 640	pr_debug("%s -> %s\n", dev->otherend, xenbus_strstate(frontend_state));
 641
 642	be->frontend_state = frontend_state;
 643
 644	switch (frontend_state) {
 645	case XenbusStateInitialising:
 646		set_backend_state(be, XenbusStateInitWait);
 
 
 
 
 647		break;
 648
 649	case XenbusStateInitialised:
 650		break;
 651
 652	case XenbusStateConnected:
 653		set_backend_state(be, XenbusStateConnected);
 
 
 
 
 654		break;
 655
 656	case XenbusStateClosing:
 657		set_backend_state(be, XenbusStateClosing);
 
 
 
 658		break;
 659
 660	case XenbusStateClosed:
 661		set_backend_state(be, XenbusStateClosed);
 662		if (xenbus_dev_is_online(dev))
 663			break;
 664		/* fall through if not online */
 665	case XenbusStateUnknown:
 666		set_backend_state(be, XenbusStateClosed);
 667		device_unregister(&dev->dev);
 668		break;
 669
 670	default:
 671		xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
 672				 frontend_state);
 673		break;
 674	}
 675}
 676
 677
 678static void xen_net_read_rate(struct xenbus_device *dev,
 679			      unsigned long *bytes, unsigned long *usec)
 680{
 681	char *s, *e;
 682	unsigned long b, u;
 683	char *ratestr;
 684
 685	/* Default to unlimited bandwidth. */
 686	*bytes = ~0UL;
 687	*usec = 0;
 688
 689	ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL);
 690	if (IS_ERR(ratestr))
 691		return;
 692
 693	s = ratestr;
 694	b = simple_strtoul(s, &e, 10);
 695	if ((s == e) || (*e != ','))
 696		goto fail;
 697
 698	s = e + 1;
 699	u = simple_strtoul(s, &e, 10);
 700	if ((s == e) || (*e != '\0'))
 701		goto fail;
 702
 703	*bytes = b;
 704	*usec = u;
 705
 706	kfree(ratestr);
 707	return;
 708
 709 fail:
 710	pr_warn("Failed to parse network rate limit. Traffic unlimited.\n");
 711	kfree(ratestr);
 712}
 713
 714static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
 715{
 716	char *s, *e, *macstr;
 717	int i;
 718
 719	macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
 720	if (IS_ERR(macstr))
 721		return PTR_ERR(macstr);
 722
 723	for (i = 0; i < ETH_ALEN; i++) {
 724		mac[i] = simple_strtoul(s, &e, 16);
 725		if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
 726			kfree(macstr);
 727			return -ENOENT;
 728		}
 729		s = e+1;
 730	}
 731
 732	kfree(macstr);
 733	return 0;
 734}
 735
 736static void xen_net_rate_changed(struct xenbus_watch *watch,
 737				const char **vec, unsigned int len)
 738{
 739	struct xenvif *vif = container_of(watch, struct xenvif, credit_watch);
 740	struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
 741	unsigned long   credit_bytes;
 742	unsigned long   credit_usec;
 743	unsigned int queue_index;
 744
 745	xen_net_read_rate(dev, &credit_bytes, &credit_usec);
 746	for (queue_index = 0; queue_index < vif->num_queues; queue_index++) {
 747		struct xenvif_queue *queue = &vif->queues[queue_index];
 748
 749		queue->credit_bytes = credit_bytes;
 750		queue->credit_usec = credit_usec;
 751		if (!mod_timer_pending(&queue->credit_timeout, jiffies) &&
 752			queue->remaining_credit > queue->credit_bytes) {
 753			queue->remaining_credit = queue->credit_bytes;
 754		}
 755	}
 756}
 757
 758static int xen_register_credit_watch(struct xenbus_device *dev,
 759				     struct xenvif *vif)
 760{
 761	int err = 0;
 762	char *node;
 763	unsigned maxlen = strlen(dev->nodename) + sizeof("/rate");
 764
 765	if (vif->credit_watch.node)
 766		return -EADDRINUSE;
 767
 768	node = kmalloc(maxlen, GFP_KERNEL);
 769	if (!node)
 770		return -ENOMEM;
 771	snprintf(node, maxlen, "%s/rate", dev->nodename);
 772	vif->credit_watch.node = node;
 773	vif->credit_watch.callback = xen_net_rate_changed;
 774	err = register_xenbus_watch(&vif->credit_watch);
 775	if (err) {
 776		pr_err("Failed to set watcher %s\n", vif->credit_watch.node);
 777		kfree(node);
 778		vif->credit_watch.node = NULL;
 779		vif->credit_watch.callback = NULL;
 780	}
 781	return err;
 782}
 783
 784static void xen_unregister_credit_watch(struct xenvif *vif)
 785{
 786	if (vif->credit_watch.node) {
 787		unregister_xenbus_watch(&vif->credit_watch);
 788		kfree(vif->credit_watch.node);
 789		vif->credit_watch.node = NULL;
 790	}
 791}
 792
 793static void xen_mcast_ctrl_changed(struct xenbus_watch *watch,
 794				   const char **vec, unsigned int len)
 795{
 796	struct xenvif *vif = container_of(watch, struct xenvif,
 797					  mcast_ctrl_watch);
 798	struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
 799
 800	vif->multicast_control = !!xenbus_read_unsigned(dev->otherend,
 801					"request-multicast-control", 0);
 802}
 803
 804static int xen_register_mcast_ctrl_watch(struct xenbus_device *dev,
 805					 struct xenvif *vif)
 806{
 807	int err = 0;
 808	char *node;
 809	unsigned maxlen = strlen(dev->otherend) +
 810		sizeof("/request-multicast-control");
 811
 812	if (vif->mcast_ctrl_watch.node) {
 813		pr_err_ratelimited("Watch is already registered\n");
 814		return -EADDRINUSE;
 815	}
 816
 817	node = kmalloc(maxlen, GFP_KERNEL);
 818	if (!node) {
 819		pr_err("Failed to allocate memory for watch\n");
 820		return -ENOMEM;
 821	}
 822	snprintf(node, maxlen, "%s/request-multicast-control",
 823		 dev->otherend);
 824	vif->mcast_ctrl_watch.node = node;
 825	vif->mcast_ctrl_watch.callback = xen_mcast_ctrl_changed;
 826	err = register_xenbus_watch(&vif->mcast_ctrl_watch);
 827	if (err) {
 828		pr_err("Failed to set watcher %s\n",
 829		       vif->mcast_ctrl_watch.node);
 830		kfree(node);
 831		vif->mcast_ctrl_watch.node = NULL;
 832		vif->mcast_ctrl_watch.callback = NULL;
 833	}
 834	return err;
 835}
 836
 837static void xen_unregister_mcast_ctrl_watch(struct xenvif *vif)
 838{
 839	if (vif->mcast_ctrl_watch.node) {
 840		unregister_xenbus_watch(&vif->mcast_ctrl_watch);
 841		kfree(vif->mcast_ctrl_watch.node);
 842		vif->mcast_ctrl_watch.node = NULL;
 843	}
 844}
 845
 846static void xen_register_watchers(struct xenbus_device *dev,
 847				  struct xenvif *vif)
 848{
 849	xen_register_credit_watch(dev, vif);
 850	xen_register_mcast_ctrl_watch(dev, vif);
 851}
 852
 853static void xen_unregister_watchers(struct xenvif *vif)
 854{
 855	xen_unregister_mcast_ctrl_watch(vif);
 856	xen_unregister_credit_watch(vif);
 857}
 858
 859static void unregister_hotplug_status_watch(struct backend_info *be)
 860{
 861	if (be->have_hotplug_status_watch) {
 862		unregister_xenbus_watch(&be->hotplug_status_watch);
 863		kfree(be->hotplug_status_watch.node);
 864	}
 865	be->have_hotplug_status_watch = 0;
 866}
 867
 868static void hotplug_status_changed(struct xenbus_watch *watch,
 869				   const char **vec,
 870				   unsigned int vec_size)
 871{
 872	struct backend_info *be = container_of(watch,
 873					       struct backend_info,
 874					       hotplug_status_watch);
 875	char *str;
 876	unsigned int len;
 877
 878	str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len);
 879	if (IS_ERR(str))
 880		return;
 881	if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) {
 882		/* Complete any pending state change */
 883		xenbus_switch_state(be->dev, be->state);
 884
 885		/* Not interested in this watch anymore. */
 886		unregister_hotplug_status_watch(be);
 887	}
 888	kfree(str);
 889}
 890
 891static int connect_ctrl_ring(struct backend_info *be)
 892{
 893	struct xenbus_device *dev = be->dev;
 894	struct xenvif *vif = be->vif;
 895	unsigned int val;
 896	grant_ref_t ring_ref;
 897	unsigned int evtchn;
 898	int err;
 899
 900	err = xenbus_scanf(XBT_NIL, dev->otherend,
 901			   "ctrl-ring-ref", "%u", &val);
 902	if (err < 0)
 903		goto done; /* The frontend does not have a control ring */
 904
 905	ring_ref = val;
 906
 907	err = xenbus_scanf(XBT_NIL, dev->otherend,
 908			   "event-channel-ctrl", "%u", &val);
 909	if (err < 0) {
 910		xenbus_dev_fatal(dev, err,
 911				 "reading %s/event-channel-ctrl",
 912				 dev->otherend);
 913		goto fail;
 914	}
 915
 916	evtchn = val;
 917
 918	err = xenvif_connect_ctrl(vif, ring_ref, evtchn);
 919	if (err) {
 920		xenbus_dev_fatal(dev, err,
 921				 "mapping shared-frame %u port %u",
 922				 ring_ref, evtchn);
 923		goto fail;
 924	}
 925
 926done:
 927	return 0;
 928
 929fail:
 930	return err;
 931}
 932
 933static void connect(struct backend_info *be)
 934{
 935	int err;
 936	struct xenbus_device *dev = be->dev;
 937	unsigned long credit_bytes, credit_usec;
 938	unsigned int queue_index;
 939	unsigned int requested_num_queues;
 940	struct xenvif_queue *queue;
 941
 942	/* Check whether the frontend requested multiple queues
 943	 * and read the number requested.
 944	 */
 945	requested_num_queues = xenbus_read_unsigned(dev->otherend,
 946					"multi-queue-num-queues", 1);
 947	if (requested_num_queues > xenvif_max_queues) {
 948		/* buggy or malicious guest */
 949		xenbus_dev_fatal(dev, -EINVAL,
 950				 "guest requested %u queues, exceeding the maximum of %u.",
 951				 requested_num_queues, xenvif_max_queues);
 952		return;
 953	}
 954
 955	err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
 956	if (err) {
 957		xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
 958		return;
 959	}
 960
 961	xen_net_read_rate(dev, &credit_bytes, &credit_usec);
 962	xen_unregister_watchers(be->vif);
 963	xen_register_watchers(dev, be->vif);
 964	read_xenbus_vif_flags(be);
 965
 966	err = connect_ctrl_ring(be);
 967	if (err) {
 968		xenbus_dev_fatal(dev, err, "connecting control ring");
 969		return;
 970	}
 971
 972	/* Use the number of queues requested by the frontend */
 973	be->vif->queues = vzalloc(requested_num_queues *
 974				  sizeof(struct xenvif_queue));
 975	if (!be->vif->queues) {
 976		xenbus_dev_fatal(dev, -ENOMEM,
 977				 "allocating queues");
 978		return;
 979	}
 980
 981	be->vif->num_queues = requested_num_queues;
 982	be->vif->stalled_queues = requested_num_queues;
 983
 984	for (queue_index = 0; queue_index < requested_num_queues; ++queue_index) {
 985		queue = &be->vif->queues[queue_index];
 986		queue->vif = be->vif;
 987		queue->id = queue_index;
 988		snprintf(queue->name, sizeof(queue->name), "%s-q%u",
 989				be->vif->dev->name, queue->id);
 990
 991		err = xenvif_init_queue(queue);
 992		if (err) {
 993			/* xenvif_init_queue() cleans up after itself on
 994			 * failure, but we need to clean up any previously
 995			 * initialised queues. Set num_queues to i so that
 996			 * earlier queues can be destroyed using the regular
 997			 * disconnect logic.
 998			 */
 999			be->vif->num_queues = queue_index;
1000			goto err;
1001		}
1002
1003		queue->credit_bytes = credit_bytes;
1004		queue->remaining_credit = credit_bytes;
1005		queue->credit_usec = credit_usec;
1006
1007		err = connect_data_rings(be, queue);
1008		if (err) {
1009			/* connect_data_rings() cleans up after itself on
1010			 * failure, but we need to clean up after
1011			 * xenvif_init_queue() here, and also clean up any
1012			 * previously initialised queues.
1013			 */
1014			xenvif_deinit_queue(queue);
1015			be->vif->num_queues = queue_index;
1016			goto err;
1017		}
1018	}
1019
1020#ifdef CONFIG_DEBUG_FS
1021	xenvif_debugfs_addif(be->vif);
1022#endif /* CONFIG_DEBUG_FS */
1023
1024	/* Initialisation completed, tell core driver the number of
1025	 * active queues.
1026	 */
1027	rtnl_lock();
1028	netif_set_real_num_tx_queues(be->vif->dev, requested_num_queues);
1029	netif_set_real_num_rx_queues(be->vif->dev, requested_num_queues);
1030	rtnl_unlock();
1031
1032	xenvif_carrier_on(be->vif);
1033
1034	unregister_hotplug_status_watch(be);
1035	err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
1036				   hotplug_status_changed,
1037				   "%s/%s", dev->nodename, "hotplug-status");
1038	if (!err)
 
 
 
1039		be->have_hotplug_status_watch = 1;
 
1040
1041	netif_tx_wake_all_queues(be->vif->dev);
1042
1043	return;
1044
1045err:
1046	if (be->vif->num_queues > 0)
1047		xenvif_disconnect_data(be->vif); /* Clean up existing queues */
1048	for (queue_index = 0; queue_index < be->vif->num_queues; ++queue_index)
1049		xenvif_deinit_queue(&be->vif->queues[queue_index]);
1050	vfree(be->vif->queues);
1051	be->vif->queues = NULL;
1052	be->vif->num_queues = 0;
1053	xenvif_disconnect_ctrl(be->vif);
1054	return;
1055}
1056
1057
1058static int connect_data_rings(struct backend_info *be,
1059			      struct xenvif_queue *queue)
1060{
 
1061	struct xenbus_device *dev = be->dev;
1062	unsigned int num_queues = queue->vif->num_queues;
1063	unsigned long tx_ring_ref, rx_ring_ref;
1064	unsigned int tx_evtchn, rx_evtchn;
1065	int err;
1066	char *xspath;
1067	size_t xspathsize;
1068	const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */
1069
1070	/* If the frontend requested 1 queue, or we have fallen back
1071	 * to single queue due to lack of frontend support for multi-
1072	 * queue, expect the remaining XenStore keys in the toplevel
1073	 * directory. Otherwise, expect them in a subdirectory called
1074	 * queue-N.
1075	 */
1076	if (num_queues == 1) {
1077		xspath = kzalloc(strlen(dev->otherend) + 1, GFP_KERNEL);
1078		if (!xspath) {
1079			xenbus_dev_fatal(dev, -ENOMEM,
1080					 "reading ring references");
1081			return -ENOMEM;
1082		}
1083		strcpy(xspath, dev->otherend);
1084	} else {
1085		xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
1086		xspath = kzalloc(xspathsize, GFP_KERNEL);
1087		if (!xspath) {
1088			xenbus_dev_fatal(dev, -ENOMEM,
1089					 "reading ring references");
1090			return -ENOMEM;
1091		}
1092		snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend,
1093			 queue->id);
1094	}
1095
1096	err = xenbus_gather(XBT_NIL, xspath,
1097			    "tx-ring-ref", "%lu", &tx_ring_ref,
1098			    "rx-ring-ref", "%lu", &rx_ring_ref, NULL);
1099	if (err) {
1100		xenbus_dev_fatal(dev, err,
1101				 "reading %s/ring-ref",
1102				 xspath);
1103		goto err;
1104	}
1105
1106	/* Try split event channels first, then single event channel. */
1107	err = xenbus_gather(XBT_NIL, xspath,
1108			    "event-channel-tx", "%u", &tx_evtchn,
1109			    "event-channel-rx", "%u", &rx_evtchn, NULL);
1110	if (err < 0) {
1111		err = xenbus_scanf(XBT_NIL, xspath,
1112				   "event-channel", "%u", &tx_evtchn);
1113		if (err < 0) {
1114			xenbus_dev_fatal(dev, err,
1115					 "reading %s/event-channel(-tx/rx)",
1116					 xspath);
1117			goto err;
1118		}
1119		rx_evtchn = tx_evtchn;
1120	}
1121
1122	/* Map the shared frame, irq etc. */
1123	err = xenvif_connect_data(queue, tx_ring_ref, rx_ring_ref,
1124				  tx_evtchn, rx_evtchn);
1125	if (err) {
1126		xenbus_dev_fatal(dev, err,
1127				 "mapping shared-frames %lu/%lu port tx %u rx %u",
1128				 tx_ring_ref, rx_ring_ref,
1129				 tx_evtchn, rx_evtchn);
1130		goto err;
1131	}
1132
1133	err = 0;
1134err: /* Regular return falls through with err == 0 */
1135	kfree(xspath);
1136	return err;
1137}
1138
1139static int read_xenbus_vif_flags(struct backend_info *be)
1140{
1141	struct xenvif *vif = be->vif;
1142	struct xenbus_device *dev = be->dev;
1143	unsigned int rx_copy;
1144	int err;
1145
1146	err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
1147			   &rx_copy);
1148	if (err == -ENOENT) {
1149		err = 0;
1150		rx_copy = 0;
1151	}
1152	if (err < 0) {
1153		xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy",
1154				 dev->otherend);
1155		return err;
1156	}
1157	if (!rx_copy)
1158		return -EOPNOTSUPP;
1159
1160	if (!xenbus_read_unsigned(dev->otherend, "feature-rx-notify", 0)) {
1161		/* - Reduce drain timeout to poll more frequently for
1162		 *   Rx requests.
1163		 * - Disable Rx stall detection.
1164		 */
1165		be->vif->drain_timeout = msecs_to_jiffies(30);
1166		be->vif->stall_timeout = 0;
1167	}
1168
1169	vif->can_sg = !!xenbus_read_unsigned(dev->otherend, "feature-sg", 0);
1170
1171	vif->gso_mask = 0;
1172
1173	if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv4", 0))
1174		vif->gso_mask |= GSO_BIT(TCPV4);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1175
1176	if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv6", 0))
1177		vif->gso_mask |= GSO_BIT(TCPV6);
 
 
 
 
 
 
 
 
1178
1179	vif->ip_csum = !xenbus_read_unsigned(dev->otherend,
1180					     "feature-no-csum-offload", 0);
1181
1182	vif->ipv6_csum = !!xenbus_read_unsigned(dev->otherend,
1183						"feature-ipv6-csum-offload", 0);
1184
1185	return 0;
1186}
1187
1188static const struct xenbus_device_id netback_ids[] = {
1189	{ "vif" },
1190	{ "" }
1191};
1192
1193static struct xenbus_driver netback_driver = {
1194	.ids = netback_ids,
1195	.probe = netback_probe,
1196	.remove = netback_remove,
1197	.uevent = netback_uevent,
1198	.otherend_changed = frontend_changed,
1199};
1200
1201int xenvif_xenbus_init(void)
1202{
1203	return xenbus_register_backend(&netback_driver);
1204}
1205
1206void xenvif_xenbus_fini(void)
1207{
1208	return xenbus_unregister_driver(&netback_driver);
1209}