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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Xenbus code for netif backend
4 *
5 * Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au>
6 * Copyright (C) 2005 XenSource Ltd
7*/
8
9#include "common.h"
10#include <linux/vmalloc.h>
11#include <linux/rtnetlink.h>
12
13static int connect_data_rings(struct backend_info *be,
14 struct xenvif_queue *queue);
15static void connect(struct backend_info *be);
16static int read_xenbus_vif_flags(struct backend_info *be);
17static int backend_create_xenvif(struct backend_info *be);
18static void unregister_hotplug_status_watch(struct backend_info *be);
19static void xen_unregister_watchers(struct xenvif *vif);
20static void set_backend_state(struct backend_info *be,
21 enum xenbus_state state);
22
23#ifdef CONFIG_DEBUG_FS
24struct dentry *xen_netback_dbg_root = NULL;
25
26static int xenvif_read_io_ring(struct seq_file *m, void *v)
27{
28 struct xenvif_queue *queue = m->private;
29 struct xen_netif_tx_back_ring *tx_ring = &queue->tx;
30 struct xen_netif_rx_back_ring *rx_ring = &queue->rx;
31 struct netdev_queue *dev_queue;
32
33 if (tx_ring->sring) {
34 struct xen_netif_tx_sring *sring = tx_ring->sring;
35
36 seq_printf(m, "Queue %d\nTX: nr_ents %u\n", queue->id,
37 tx_ring->nr_ents);
38 seq_printf(m, "req prod %u (%d) cons %u (%d) event %u (%d)\n",
39 sring->req_prod,
40 sring->req_prod - sring->rsp_prod,
41 tx_ring->req_cons,
42 tx_ring->req_cons - sring->rsp_prod,
43 sring->req_event,
44 sring->req_event - sring->rsp_prod);
45 seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n",
46 sring->rsp_prod,
47 tx_ring->rsp_prod_pvt,
48 tx_ring->rsp_prod_pvt - sring->rsp_prod,
49 sring->rsp_event,
50 sring->rsp_event - sring->rsp_prod);
51 seq_printf(m, "pending prod %u pending cons %u nr_pending_reqs %u\n",
52 queue->pending_prod,
53 queue->pending_cons,
54 nr_pending_reqs(queue));
55 seq_printf(m, "dealloc prod %u dealloc cons %u dealloc_queue %u\n\n",
56 queue->dealloc_prod,
57 queue->dealloc_cons,
58 queue->dealloc_prod - queue->dealloc_cons);
59 }
60
61 if (rx_ring->sring) {
62 struct xen_netif_rx_sring *sring = rx_ring->sring;
63
64 seq_printf(m, "RX: nr_ents %u\n", rx_ring->nr_ents);
65 seq_printf(m, "req prod %u (%d) cons %u (%d) event %u (%d)\n",
66 sring->req_prod,
67 sring->req_prod - sring->rsp_prod,
68 rx_ring->req_cons,
69 rx_ring->req_cons - sring->rsp_prod,
70 sring->req_event,
71 sring->req_event - sring->rsp_prod);
72 seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n\n",
73 sring->rsp_prod,
74 rx_ring->rsp_prod_pvt,
75 rx_ring->rsp_prod_pvt - sring->rsp_prod,
76 sring->rsp_event,
77 sring->rsp_event - sring->rsp_prod);
78 }
79
80 seq_printf(m, "NAPI state: %lx NAPI weight: %d TX queue len %u\n"
81 "Credit timer_pending: %d, credit: %lu, usec: %lu\n"
82 "remaining: %lu, expires: %lu, now: %lu\n",
83 queue->napi.state, queue->napi.weight,
84 skb_queue_len(&queue->tx_queue),
85 timer_pending(&queue->credit_timeout),
86 queue->credit_bytes,
87 queue->credit_usec,
88 queue->remaining_credit,
89 queue->credit_timeout.expires,
90 jiffies);
91
92 dev_queue = netdev_get_tx_queue(queue->vif->dev, queue->id);
93
94 seq_printf(m, "\nRx internal queue: len %u max %u pkts %u %s\n",
95 queue->rx_queue_len, queue->rx_queue_max,
96 skb_queue_len(&queue->rx_queue),
97 netif_tx_queue_stopped(dev_queue) ? "stopped" : "running");
98
99 return 0;
100}
101
102#define XENVIF_KICK_STR "kick"
103#define BUFFER_SIZE 32
104
105static ssize_t
106xenvif_write_io_ring(struct file *filp, const char __user *buf, size_t count,
107 loff_t *ppos)
108{
109 struct xenvif_queue *queue =
110 ((struct seq_file *)filp->private_data)->private;
111 int len;
112 char write[BUFFER_SIZE];
113
114 /* don't allow partial writes and check the length */
115 if (*ppos != 0)
116 return 0;
117 if (count >= sizeof(write))
118 return -ENOSPC;
119
120 len = simple_write_to_buffer(write,
121 sizeof(write) - 1,
122 ppos,
123 buf,
124 count);
125 if (len < 0)
126 return len;
127
128 write[len] = '\0';
129
130 if (!strncmp(write, XENVIF_KICK_STR, sizeof(XENVIF_KICK_STR) - 1))
131 xenvif_interrupt(0, (void *)queue);
132 else {
133 pr_warn("Unknown command to io_ring_q%d. Available: kick\n",
134 queue->id);
135 count = -EINVAL;
136 }
137 return count;
138}
139
140static int xenvif_io_ring_open(struct inode *inode, struct file *filp)
141{
142 int ret;
143 void *queue = NULL;
144
145 if (inode->i_private)
146 queue = inode->i_private;
147 ret = single_open(filp, xenvif_read_io_ring, queue);
148 filp->f_mode |= FMODE_PWRITE;
149 return ret;
150}
151
152static const struct file_operations xenvif_dbg_io_ring_ops_fops = {
153 .owner = THIS_MODULE,
154 .open = xenvif_io_ring_open,
155 .read = seq_read,
156 .llseek = seq_lseek,
157 .release = single_release,
158 .write = xenvif_write_io_ring,
159};
160
161static int xenvif_ctrl_show(struct seq_file *m, void *v)
162{
163 struct xenvif *vif = m->private;
164
165 xenvif_dump_hash_info(vif, m);
166
167 return 0;
168}
169DEFINE_SHOW_ATTRIBUTE(xenvif_ctrl);
170
171static void xenvif_debugfs_addif(struct xenvif *vif)
172{
173 int i;
174
175 vif->xenvif_dbg_root = debugfs_create_dir(vif->dev->name,
176 xen_netback_dbg_root);
177 for (i = 0; i < vif->num_queues; ++i) {
178 char filename[sizeof("io_ring_q") + 4];
179
180 snprintf(filename, sizeof(filename), "io_ring_q%d", i);
181 debugfs_create_file(filename, 0600, vif->xenvif_dbg_root,
182 &vif->queues[i],
183 &xenvif_dbg_io_ring_ops_fops);
184 }
185
186 if (vif->ctrl_irq)
187 debugfs_create_file("ctrl", 0400, vif->xenvif_dbg_root, vif,
188 &xenvif_ctrl_fops);
189}
190
191static void xenvif_debugfs_delif(struct xenvif *vif)
192{
193 debugfs_remove_recursive(vif->xenvif_dbg_root);
194 vif->xenvif_dbg_root = NULL;
195}
196#endif /* CONFIG_DEBUG_FS */
197
198static int netback_remove(struct xenbus_device *dev)
199{
200 struct backend_info *be = dev_get_drvdata(&dev->dev);
201
202 set_backend_state(be, XenbusStateClosed);
203
204 unregister_hotplug_status_watch(be);
205 if (be->vif) {
206 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
207 xen_unregister_watchers(be->vif);
208 xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
209 xenvif_free(be->vif);
210 be->vif = NULL;
211 }
212 kfree(be->hotplug_script);
213 kfree(be);
214 dev_set_drvdata(&dev->dev, NULL);
215 return 0;
216}
217
218
219/**
220 * Entry point to this code when a new device is created. Allocate the basic
221 * structures and switch to InitWait.
222 */
223static int netback_probe(struct xenbus_device *dev,
224 const struct xenbus_device_id *id)
225{
226 const char *message;
227 struct xenbus_transaction xbt;
228 int err;
229 int sg;
230 const char *script;
231 struct backend_info *be = kzalloc(sizeof(struct backend_info),
232 GFP_KERNEL);
233 if (!be) {
234 xenbus_dev_fatal(dev, -ENOMEM,
235 "allocating backend structure");
236 return -ENOMEM;
237 }
238
239 be->dev = dev;
240 dev_set_drvdata(&dev->dev, be);
241
242 be->state = XenbusStateInitialising;
243 err = xenbus_switch_state(dev, XenbusStateInitialising);
244 if (err)
245 goto fail;
246
247 sg = 1;
248
249 do {
250 err = xenbus_transaction_start(&xbt);
251 if (err) {
252 xenbus_dev_fatal(dev, err, "starting transaction");
253 goto fail;
254 }
255
256 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", sg);
257 if (err) {
258 message = "writing feature-sg";
259 goto abort_transaction;
260 }
261
262 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4",
263 "%d", sg);
264 if (err) {
265 message = "writing feature-gso-tcpv4";
266 goto abort_transaction;
267 }
268
269 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv6",
270 "%d", sg);
271 if (err) {
272 message = "writing feature-gso-tcpv6";
273 goto abort_transaction;
274 }
275
276 /* We support partial checksum setup for IPv6 packets */
277 err = xenbus_printf(xbt, dev->nodename,
278 "feature-ipv6-csum-offload",
279 "%d", 1);
280 if (err) {
281 message = "writing feature-ipv6-csum-offload";
282 goto abort_transaction;
283 }
284
285 /* We support rx-copy path. */
286 err = xenbus_printf(xbt, dev->nodename,
287 "feature-rx-copy", "%d", 1);
288 if (err) {
289 message = "writing feature-rx-copy";
290 goto abort_transaction;
291 }
292
293 /*
294 * We don't support rx-flip path (except old guests who don't
295 * grok this feature flag).
296 */
297 err = xenbus_printf(xbt, dev->nodename,
298 "feature-rx-flip", "%d", 0);
299 if (err) {
300 message = "writing feature-rx-flip";
301 goto abort_transaction;
302 }
303
304 /* We support dynamic multicast-control. */
305 err = xenbus_printf(xbt, dev->nodename,
306 "feature-multicast-control", "%d", 1);
307 if (err) {
308 message = "writing feature-multicast-control";
309 goto abort_transaction;
310 }
311
312 err = xenbus_printf(xbt, dev->nodename,
313 "feature-dynamic-multicast-control",
314 "%d", 1);
315 if (err) {
316 message = "writing feature-dynamic-multicast-control";
317 goto abort_transaction;
318 }
319
320 err = xenbus_transaction_end(xbt, 0);
321 } while (err == -EAGAIN);
322
323 if (err) {
324 xenbus_dev_fatal(dev, err, "completing transaction");
325 goto fail;
326 }
327
328 /*
329 * Split event channels support, this is optional so it is not
330 * put inside the above loop.
331 */
332 err = xenbus_printf(XBT_NIL, dev->nodename,
333 "feature-split-event-channels",
334 "%u", separate_tx_rx_irq);
335 if (err)
336 pr_debug("Error writing feature-split-event-channels\n");
337
338 /* Multi-queue support: This is an optional feature. */
339 err = xenbus_printf(XBT_NIL, dev->nodename,
340 "multi-queue-max-queues", "%u", xenvif_max_queues);
341 if (err)
342 pr_debug("Error writing multi-queue-max-queues\n");
343
344 err = xenbus_printf(XBT_NIL, dev->nodename,
345 "feature-ctrl-ring",
346 "%u", true);
347 if (err)
348 pr_debug("Error writing feature-ctrl-ring\n");
349
350 script = xenbus_read(XBT_NIL, dev->nodename, "script", NULL);
351 if (IS_ERR(script)) {
352 err = PTR_ERR(script);
353 xenbus_dev_fatal(dev, err, "reading script");
354 goto fail;
355 }
356
357 be->hotplug_script = script;
358
359
360 /* This kicks hotplug scripts, so do it immediately. */
361 err = backend_create_xenvif(be);
362 if (err)
363 goto fail;
364
365 return 0;
366
367abort_transaction:
368 xenbus_transaction_end(xbt, 1);
369 xenbus_dev_fatal(dev, err, "%s", message);
370fail:
371 pr_debug("failed\n");
372 netback_remove(dev);
373 return err;
374}
375
376
377/*
378 * Handle the creation of the hotplug script environment. We add the script
379 * and vif variables to the environment, for the benefit of the vif-* hotplug
380 * scripts.
381 */
382static int netback_uevent(struct xenbus_device *xdev,
383 struct kobj_uevent_env *env)
384{
385 struct backend_info *be = dev_get_drvdata(&xdev->dev);
386
387 if (!be)
388 return 0;
389
390 if (add_uevent_var(env, "script=%s", be->hotplug_script))
391 return -ENOMEM;
392
393 if (!be->vif)
394 return 0;
395
396 return add_uevent_var(env, "vif=%s", be->vif->dev->name);
397}
398
399
400static int backend_create_xenvif(struct backend_info *be)
401{
402 int err;
403 long handle;
404 struct xenbus_device *dev = be->dev;
405 struct xenvif *vif;
406
407 if (be->vif != NULL)
408 return 0;
409
410 err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle);
411 if (err != 1) {
412 xenbus_dev_fatal(dev, err, "reading handle");
413 return (err < 0) ? err : -EINVAL;
414 }
415
416 vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle);
417 if (IS_ERR(vif)) {
418 err = PTR_ERR(vif);
419 xenbus_dev_fatal(dev, err, "creating interface");
420 return err;
421 }
422 be->vif = vif;
423 vif->be = be;
424
425 kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE);
426 return 0;
427}
428
429static void backend_disconnect(struct backend_info *be)
430{
431 struct xenvif *vif = be->vif;
432
433 if (vif) {
434 unsigned int num_queues = vif->num_queues;
435 unsigned int queue_index;
436
437 xen_unregister_watchers(vif);
438#ifdef CONFIG_DEBUG_FS
439 xenvif_debugfs_delif(vif);
440#endif /* CONFIG_DEBUG_FS */
441 xenvif_disconnect_data(vif);
442
443 /* At this point some of the handlers may still be active
444 * so we need to have additional synchronization here.
445 */
446 vif->num_queues = 0;
447 synchronize_net();
448
449 for (queue_index = 0; queue_index < num_queues; ++queue_index)
450 xenvif_deinit_queue(&vif->queues[queue_index]);
451
452 vfree(vif->queues);
453 vif->queues = NULL;
454
455 xenvif_disconnect_ctrl(vif);
456 }
457}
458
459static void backend_connect(struct backend_info *be)
460{
461 if (be->vif)
462 connect(be);
463}
464
465static inline void backend_switch_state(struct backend_info *be,
466 enum xenbus_state state)
467{
468 struct xenbus_device *dev = be->dev;
469
470 pr_debug("%s -> %s\n", dev->nodename, xenbus_strstate(state));
471 be->state = state;
472
473 /* If we are waiting for a hotplug script then defer the
474 * actual xenbus state change.
475 */
476 if (!be->have_hotplug_status_watch)
477 xenbus_switch_state(dev, state);
478}
479
480/* Handle backend state transitions:
481 *
482 * The backend state starts in Initialising and the following transitions are
483 * allowed.
484 *
485 * Initialising -> InitWait -> Connected
486 * \
487 * \ ^ \ |
488 * \ | \ |
489 * \ | \ |
490 * \ | \ |
491 * \ | \ |
492 * \ | \ |
493 * V | V V
494 *
495 * Closed <-> Closing
496 *
497 * The state argument specifies the eventual state of the backend and the
498 * function transitions to that state via the shortest path.
499 */
500static void set_backend_state(struct backend_info *be,
501 enum xenbus_state state)
502{
503 while (be->state != state) {
504 switch (be->state) {
505 case XenbusStateInitialising:
506 switch (state) {
507 case XenbusStateInitWait:
508 case XenbusStateConnected:
509 case XenbusStateClosing:
510 backend_switch_state(be, XenbusStateInitWait);
511 break;
512 case XenbusStateClosed:
513 backend_switch_state(be, XenbusStateClosed);
514 break;
515 default:
516 BUG();
517 }
518 break;
519 case XenbusStateClosed:
520 switch (state) {
521 case XenbusStateInitWait:
522 case XenbusStateConnected:
523 backend_switch_state(be, XenbusStateInitWait);
524 break;
525 case XenbusStateClosing:
526 backend_switch_state(be, XenbusStateClosing);
527 break;
528 default:
529 BUG();
530 }
531 break;
532 case XenbusStateInitWait:
533 switch (state) {
534 case XenbusStateConnected:
535 backend_connect(be);
536 backend_switch_state(be, XenbusStateConnected);
537 break;
538 case XenbusStateClosing:
539 case XenbusStateClosed:
540 backend_switch_state(be, XenbusStateClosing);
541 break;
542 default:
543 BUG();
544 }
545 break;
546 case XenbusStateConnected:
547 switch (state) {
548 case XenbusStateInitWait:
549 case XenbusStateClosing:
550 case XenbusStateClosed:
551 backend_disconnect(be);
552 backend_switch_state(be, XenbusStateClosing);
553 break;
554 default:
555 BUG();
556 }
557 break;
558 case XenbusStateClosing:
559 switch (state) {
560 case XenbusStateInitWait:
561 case XenbusStateConnected:
562 case XenbusStateClosed:
563 backend_switch_state(be, XenbusStateClosed);
564 break;
565 default:
566 BUG();
567 }
568 break;
569 default:
570 BUG();
571 }
572 }
573}
574
575/**
576 * Callback received when the frontend's state changes.
577 */
578static void frontend_changed(struct xenbus_device *dev,
579 enum xenbus_state frontend_state)
580{
581 struct backend_info *be = dev_get_drvdata(&dev->dev);
582
583 pr_debug("%s -> %s\n", dev->otherend, xenbus_strstate(frontend_state));
584
585 be->frontend_state = frontend_state;
586
587 switch (frontend_state) {
588 case XenbusStateInitialising:
589 set_backend_state(be, XenbusStateInitWait);
590 break;
591
592 case XenbusStateInitialised:
593 break;
594
595 case XenbusStateConnected:
596 set_backend_state(be, XenbusStateConnected);
597 break;
598
599 case XenbusStateClosing:
600 set_backend_state(be, XenbusStateClosing);
601 break;
602
603 case XenbusStateClosed:
604 set_backend_state(be, XenbusStateClosed);
605 if (xenbus_dev_is_online(dev))
606 break;
607 /* fall through - if not online */
608 case XenbusStateUnknown:
609 set_backend_state(be, XenbusStateClosed);
610 device_unregister(&dev->dev);
611 break;
612
613 default:
614 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
615 frontend_state);
616 break;
617 }
618}
619
620
621static void xen_net_read_rate(struct xenbus_device *dev,
622 unsigned long *bytes, unsigned long *usec)
623{
624 char *s, *e;
625 unsigned long b, u;
626 char *ratestr;
627
628 /* Default to unlimited bandwidth. */
629 *bytes = ~0UL;
630 *usec = 0;
631
632 ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL);
633 if (IS_ERR(ratestr))
634 return;
635
636 s = ratestr;
637 b = simple_strtoul(s, &e, 10);
638 if ((s == e) || (*e != ','))
639 goto fail;
640
641 s = e + 1;
642 u = simple_strtoul(s, &e, 10);
643 if ((s == e) || (*e != '\0'))
644 goto fail;
645
646 *bytes = b;
647 *usec = u;
648
649 kfree(ratestr);
650 return;
651
652 fail:
653 pr_warn("Failed to parse network rate limit. Traffic unlimited.\n");
654 kfree(ratestr);
655}
656
657static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
658{
659 char *s, *e, *macstr;
660 int i;
661
662 macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
663 if (IS_ERR(macstr))
664 return PTR_ERR(macstr);
665
666 for (i = 0; i < ETH_ALEN; i++) {
667 mac[i] = simple_strtoul(s, &e, 16);
668 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
669 kfree(macstr);
670 return -ENOENT;
671 }
672 s = e+1;
673 }
674
675 kfree(macstr);
676 return 0;
677}
678
679static void xen_net_rate_changed(struct xenbus_watch *watch,
680 const char *path, const char *token)
681{
682 struct xenvif *vif = container_of(watch, struct xenvif, credit_watch);
683 struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
684 unsigned long credit_bytes;
685 unsigned long credit_usec;
686 unsigned int queue_index;
687
688 xen_net_read_rate(dev, &credit_bytes, &credit_usec);
689 for (queue_index = 0; queue_index < vif->num_queues; queue_index++) {
690 struct xenvif_queue *queue = &vif->queues[queue_index];
691
692 queue->credit_bytes = credit_bytes;
693 queue->credit_usec = credit_usec;
694 if (!mod_timer_pending(&queue->credit_timeout, jiffies) &&
695 queue->remaining_credit > queue->credit_bytes) {
696 queue->remaining_credit = queue->credit_bytes;
697 }
698 }
699}
700
701static int xen_register_credit_watch(struct xenbus_device *dev,
702 struct xenvif *vif)
703{
704 int err = 0;
705 char *node;
706 unsigned maxlen = strlen(dev->nodename) + sizeof("/rate");
707
708 if (vif->credit_watch.node)
709 return -EADDRINUSE;
710
711 node = kmalloc(maxlen, GFP_KERNEL);
712 if (!node)
713 return -ENOMEM;
714 snprintf(node, maxlen, "%s/rate", dev->nodename);
715 vif->credit_watch.node = node;
716 vif->credit_watch.callback = xen_net_rate_changed;
717 err = register_xenbus_watch(&vif->credit_watch);
718 if (err) {
719 pr_err("Failed to set watcher %s\n", vif->credit_watch.node);
720 kfree(node);
721 vif->credit_watch.node = NULL;
722 vif->credit_watch.callback = NULL;
723 }
724 return err;
725}
726
727static void xen_unregister_credit_watch(struct xenvif *vif)
728{
729 if (vif->credit_watch.node) {
730 unregister_xenbus_watch(&vif->credit_watch);
731 kfree(vif->credit_watch.node);
732 vif->credit_watch.node = NULL;
733 }
734}
735
736static void xen_mcast_ctrl_changed(struct xenbus_watch *watch,
737 const char *path, const char *token)
738{
739 struct xenvif *vif = container_of(watch, struct xenvif,
740 mcast_ctrl_watch);
741 struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
742
743 vif->multicast_control = !!xenbus_read_unsigned(dev->otherend,
744 "request-multicast-control", 0);
745}
746
747static int xen_register_mcast_ctrl_watch(struct xenbus_device *dev,
748 struct xenvif *vif)
749{
750 int err = 0;
751 char *node;
752 unsigned maxlen = strlen(dev->otherend) +
753 sizeof("/request-multicast-control");
754
755 if (vif->mcast_ctrl_watch.node) {
756 pr_err_ratelimited("Watch is already registered\n");
757 return -EADDRINUSE;
758 }
759
760 node = kmalloc(maxlen, GFP_KERNEL);
761 if (!node) {
762 pr_err("Failed to allocate memory for watch\n");
763 return -ENOMEM;
764 }
765 snprintf(node, maxlen, "%s/request-multicast-control",
766 dev->otherend);
767 vif->mcast_ctrl_watch.node = node;
768 vif->mcast_ctrl_watch.callback = xen_mcast_ctrl_changed;
769 err = register_xenbus_watch(&vif->mcast_ctrl_watch);
770 if (err) {
771 pr_err("Failed to set watcher %s\n",
772 vif->mcast_ctrl_watch.node);
773 kfree(node);
774 vif->mcast_ctrl_watch.node = NULL;
775 vif->mcast_ctrl_watch.callback = NULL;
776 }
777 return err;
778}
779
780static void xen_unregister_mcast_ctrl_watch(struct xenvif *vif)
781{
782 if (vif->mcast_ctrl_watch.node) {
783 unregister_xenbus_watch(&vif->mcast_ctrl_watch);
784 kfree(vif->mcast_ctrl_watch.node);
785 vif->mcast_ctrl_watch.node = NULL;
786 }
787}
788
789static void xen_register_watchers(struct xenbus_device *dev,
790 struct xenvif *vif)
791{
792 xen_register_credit_watch(dev, vif);
793 xen_register_mcast_ctrl_watch(dev, vif);
794}
795
796static void xen_unregister_watchers(struct xenvif *vif)
797{
798 xen_unregister_mcast_ctrl_watch(vif);
799 xen_unregister_credit_watch(vif);
800}
801
802static void unregister_hotplug_status_watch(struct backend_info *be)
803{
804 if (be->have_hotplug_status_watch) {
805 unregister_xenbus_watch(&be->hotplug_status_watch);
806 kfree(be->hotplug_status_watch.node);
807 }
808 be->have_hotplug_status_watch = 0;
809}
810
811static void hotplug_status_changed(struct xenbus_watch *watch,
812 const char *path,
813 const char *token)
814{
815 struct backend_info *be = container_of(watch,
816 struct backend_info,
817 hotplug_status_watch);
818 char *str;
819 unsigned int len;
820
821 str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len);
822 if (IS_ERR(str))
823 return;
824 if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) {
825 /* Complete any pending state change */
826 xenbus_switch_state(be->dev, be->state);
827
828 /* Not interested in this watch anymore. */
829 unregister_hotplug_status_watch(be);
830 }
831 kfree(str);
832}
833
834static int connect_ctrl_ring(struct backend_info *be)
835{
836 struct xenbus_device *dev = be->dev;
837 struct xenvif *vif = be->vif;
838 unsigned int val;
839 grant_ref_t ring_ref;
840 unsigned int evtchn;
841 int err;
842
843 err = xenbus_scanf(XBT_NIL, dev->otherend,
844 "ctrl-ring-ref", "%u", &val);
845 if (err < 0)
846 goto done; /* The frontend does not have a control ring */
847
848 ring_ref = val;
849
850 err = xenbus_scanf(XBT_NIL, dev->otherend,
851 "event-channel-ctrl", "%u", &val);
852 if (err < 0) {
853 xenbus_dev_fatal(dev, err,
854 "reading %s/event-channel-ctrl",
855 dev->otherend);
856 goto fail;
857 }
858
859 evtchn = val;
860
861 err = xenvif_connect_ctrl(vif, ring_ref, evtchn);
862 if (err) {
863 xenbus_dev_fatal(dev, err,
864 "mapping shared-frame %u port %u",
865 ring_ref, evtchn);
866 goto fail;
867 }
868
869done:
870 return 0;
871
872fail:
873 return err;
874}
875
876static void connect(struct backend_info *be)
877{
878 int err;
879 struct xenbus_device *dev = be->dev;
880 unsigned long credit_bytes, credit_usec;
881 unsigned int queue_index;
882 unsigned int requested_num_queues;
883 struct xenvif_queue *queue;
884
885 /* Check whether the frontend requested multiple queues
886 * and read the number requested.
887 */
888 requested_num_queues = xenbus_read_unsigned(dev->otherend,
889 "multi-queue-num-queues", 1);
890 if (requested_num_queues > xenvif_max_queues) {
891 /* buggy or malicious guest */
892 xenbus_dev_fatal(dev, -EINVAL,
893 "guest requested %u queues, exceeding the maximum of %u.",
894 requested_num_queues, xenvif_max_queues);
895 return;
896 }
897
898 err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
899 if (err) {
900 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
901 return;
902 }
903
904 xen_net_read_rate(dev, &credit_bytes, &credit_usec);
905 xen_unregister_watchers(be->vif);
906 xen_register_watchers(dev, be->vif);
907 read_xenbus_vif_flags(be);
908
909 err = connect_ctrl_ring(be);
910 if (err) {
911 xenbus_dev_fatal(dev, err, "connecting control ring");
912 return;
913 }
914
915 /* Use the number of queues requested by the frontend */
916 be->vif->queues = vzalloc(array_size(requested_num_queues,
917 sizeof(struct xenvif_queue)));
918 if (!be->vif->queues) {
919 xenbus_dev_fatal(dev, -ENOMEM,
920 "allocating queues");
921 return;
922 }
923
924 be->vif->num_queues = requested_num_queues;
925 be->vif->stalled_queues = requested_num_queues;
926
927 for (queue_index = 0; queue_index < requested_num_queues; ++queue_index) {
928 queue = &be->vif->queues[queue_index];
929 queue->vif = be->vif;
930 queue->id = queue_index;
931 snprintf(queue->name, sizeof(queue->name), "%s-q%u",
932 be->vif->dev->name, queue->id);
933
934 err = xenvif_init_queue(queue);
935 if (err) {
936 /* xenvif_init_queue() cleans up after itself on
937 * failure, but we need to clean up any previously
938 * initialised queues. Set num_queues to i so that
939 * earlier queues can be destroyed using the regular
940 * disconnect logic.
941 */
942 be->vif->num_queues = queue_index;
943 goto err;
944 }
945
946 queue->credit_bytes = credit_bytes;
947 queue->remaining_credit = credit_bytes;
948 queue->credit_usec = credit_usec;
949
950 err = connect_data_rings(be, queue);
951 if (err) {
952 /* connect_data_rings() cleans up after itself on
953 * failure, but we need to clean up after
954 * xenvif_init_queue() here, and also clean up any
955 * previously initialised queues.
956 */
957 xenvif_deinit_queue(queue);
958 be->vif->num_queues = queue_index;
959 goto err;
960 }
961 }
962
963#ifdef CONFIG_DEBUG_FS
964 xenvif_debugfs_addif(be->vif);
965#endif /* CONFIG_DEBUG_FS */
966
967 /* Initialisation completed, tell core driver the number of
968 * active queues.
969 */
970 rtnl_lock();
971 netif_set_real_num_tx_queues(be->vif->dev, requested_num_queues);
972 netif_set_real_num_rx_queues(be->vif->dev, requested_num_queues);
973 rtnl_unlock();
974
975 xenvif_carrier_on(be->vif);
976
977 unregister_hotplug_status_watch(be);
978 err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
979 hotplug_status_changed,
980 "%s/%s", dev->nodename, "hotplug-status");
981 if (!err)
982 be->have_hotplug_status_watch = 1;
983
984 netif_tx_wake_all_queues(be->vif->dev);
985
986 return;
987
988err:
989 if (be->vif->num_queues > 0)
990 xenvif_disconnect_data(be->vif); /* Clean up existing queues */
991 for (queue_index = 0; queue_index < be->vif->num_queues; ++queue_index)
992 xenvif_deinit_queue(&be->vif->queues[queue_index]);
993 vfree(be->vif->queues);
994 be->vif->queues = NULL;
995 be->vif->num_queues = 0;
996 xenvif_disconnect_ctrl(be->vif);
997 return;
998}
999
1000
1001static int connect_data_rings(struct backend_info *be,
1002 struct xenvif_queue *queue)
1003{
1004 struct xenbus_device *dev = be->dev;
1005 unsigned int num_queues = queue->vif->num_queues;
1006 unsigned long tx_ring_ref, rx_ring_ref;
1007 unsigned int tx_evtchn, rx_evtchn;
1008 int err;
1009 char *xspath;
1010 size_t xspathsize;
1011 const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */
1012
1013 /* If the frontend requested 1 queue, or we have fallen back
1014 * to single queue due to lack of frontend support for multi-
1015 * queue, expect the remaining XenStore keys in the toplevel
1016 * directory. Otherwise, expect them in a subdirectory called
1017 * queue-N.
1018 */
1019 if (num_queues == 1) {
1020 xspath = kzalloc(strlen(dev->otherend) + 1, GFP_KERNEL);
1021 if (!xspath) {
1022 xenbus_dev_fatal(dev, -ENOMEM,
1023 "reading ring references");
1024 return -ENOMEM;
1025 }
1026 strcpy(xspath, dev->otherend);
1027 } else {
1028 xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
1029 xspath = kzalloc(xspathsize, GFP_KERNEL);
1030 if (!xspath) {
1031 xenbus_dev_fatal(dev, -ENOMEM,
1032 "reading ring references");
1033 return -ENOMEM;
1034 }
1035 snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend,
1036 queue->id);
1037 }
1038
1039 err = xenbus_gather(XBT_NIL, xspath,
1040 "tx-ring-ref", "%lu", &tx_ring_ref,
1041 "rx-ring-ref", "%lu", &rx_ring_ref, NULL);
1042 if (err) {
1043 xenbus_dev_fatal(dev, err,
1044 "reading %s/ring-ref",
1045 xspath);
1046 goto err;
1047 }
1048
1049 /* Try split event channels first, then single event channel. */
1050 err = xenbus_gather(XBT_NIL, xspath,
1051 "event-channel-tx", "%u", &tx_evtchn,
1052 "event-channel-rx", "%u", &rx_evtchn, NULL);
1053 if (err < 0) {
1054 err = xenbus_scanf(XBT_NIL, xspath,
1055 "event-channel", "%u", &tx_evtchn);
1056 if (err < 0) {
1057 xenbus_dev_fatal(dev, err,
1058 "reading %s/event-channel(-tx/rx)",
1059 xspath);
1060 goto err;
1061 }
1062 rx_evtchn = tx_evtchn;
1063 }
1064
1065 /* Map the shared frame, irq etc. */
1066 err = xenvif_connect_data(queue, tx_ring_ref, rx_ring_ref,
1067 tx_evtchn, rx_evtchn);
1068 if (err) {
1069 xenbus_dev_fatal(dev, err,
1070 "mapping shared-frames %lu/%lu port tx %u rx %u",
1071 tx_ring_ref, rx_ring_ref,
1072 tx_evtchn, rx_evtchn);
1073 goto err;
1074 }
1075
1076 err = 0;
1077err: /* Regular return falls through with err == 0 */
1078 kfree(xspath);
1079 return err;
1080}
1081
1082static int read_xenbus_vif_flags(struct backend_info *be)
1083{
1084 struct xenvif *vif = be->vif;
1085 struct xenbus_device *dev = be->dev;
1086 unsigned int rx_copy;
1087 int err;
1088
1089 err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
1090 &rx_copy);
1091 if (err == -ENOENT) {
1092 err = 0;
1093 rx_copy = 0;
1094 }
1095 if (err < 0) {
1096 xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy",
1097 dev->otherend);
1098 return err;
1099 }
1100 if (!rx_copy)
1101 return -EOPNOTSUPP;
1102
1103 if (!xenbus_read_unsigned(dev->otherend, "feature-rx-notify", 0)) {
1104 /* - Reduce drain timeout to poll more frequently for
1105 * Rx requests.
1106 * - Disable Rx stall detection.
1107 */
1108 be->vif->drain_timeout = msecs_to_jiffies(30);
1109 be->vif->stall_timeout = 0;
1110 }
1111
1112 vif->can_sg = !!xenbus_read_unsigned(dev->otherend, "feature-sg", 0);
1113
1114 vif->gso_mask = 0;
1115
1116 if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv4", 0))
1117 vif->gso_mask |= GSO_BIT(TCPV4);
1118
1119 if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv6", 0))
1120 vif->gso_mask |= GSO_BIT(TCPV6);
1121
1122 vif->ip_csum = !xenbus_read_unsigned(dev->otherend,
1123 "feature-no-csum-offload", 0);
1124
1125 vif->ipv6_csum = !!xenbus_read_unsigned(dev->otherend,
1126 "feature-ipv6-csum-offload", 0);
1127
1128 return 0;
1129}
1130
1131static const struct xenbus_device_id netback_ids[] = {
1132 { "vif" },
1133 { "" }
1134};
1135
1136static struct xenbus_driver netback_driver = {
1137 .ids = netback_ids,
1138 .probe = netback_probe,
1139 .remove = netback_remove,
1140 .uevent = netback_uevent,
1141 .otherend_changed = frontend_changed,
1142};
1143
1144int xenvif_xenbus_init(void)
1145{
1146 return xenbus_register_backend(&netback_driver);
1147}
1148
1149void xenvif_xenbus_fini(void)
1150{
1151 return xenbus_unregister_driver(&netback_driver);
1152}
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_rings(struct backend_info *be, struct xenvif_queue *queue);
42static void connect(struct backend_info *be);
43static int read_xenbus_vif_flags(struct backend_info *be);
44static int backend_create_xenvif(struct backend_info *be);
45static void unregister_hotplug_status_watch(struct backend_info *be);
46static void xen_unregister_watchers(struct xenvif *vif);
47static void set_backend_state(struct backend_info *be,
48 enum xenbus_state state);
49
50#ifdef CONFIG_DEBUG_FS
51struct dentry *xen_netback_dbg_root = NULL;
52
53static int xenvif_read_io_ring(struct seq_file *m, void *v)
54{
55 struct xenvif_queue *queue = m->private;
56 struct xen_netif_tx_back_ring *tx_ring = &queue->tx;
57 struct xen_netif_rx_back_ring *rx_ring = &queue->rx;
58 struct netdev_queue *dev_queue;
59
60 if (tx_ring->sring) {
61 struct xen_netif_tx_sring *sring = tx_ring->sring;
62
63 seq_printf(m, "Queue %d\nTX: nr_ents %u\n", queue->id,
64 tx_ring->nr_ents);
65 seq_printf(m, "req prod %u (%d) cons %u (%d) event %u (%d)\n",
66 sring->req_prod,
67 sring->req_prod - sring->rsp_prod,
68 tx_ring->req_cons,
69 tx_ring->req_cons - sring->rsp_prod,
70 sring->req_event,
71 sring->req_event - sring->rsp_prod);
72 seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n",
73 sring->rsp_prod,
74 tx_ring->rsp_prod_pvt,
75 tx_ring->rsp_prod_pvt - sring->rsp_prod,
76 sring->rsp_event,
77 sring->rsp_event - sring->rsp_prod);
78 seq_printf(m, "pending prod %u pending cons %u nr_pending_reqs %u\n",
79 queue->pending_prod,
80 queue->pending_cons,
81 nr_pending_reqs(queue));
82 seq_printf(m, "dealloc prod %u dealloc cons %u dealloc_queue %u\n\n",
83 queue->dealloc_prod,
84 queue->dealloc_cons,
85 queue->dealloc_prod - queue->dealloc_cons);
86 }
87
88 if (rx_ring->sring) {
89 struct xen_netif_rx_sring *sring = rx_ring->sring;
90
91 seq_printf(m, "RX: nr_ents %u\n", rx_ring->nr_ents);
92 seq_printf(m, "req prod %u (%d) cons %u (%d) event %u (%d)\n",
93 sring->req_prod,
94 sring->req_prod - sring->rsp_prod,
95 rx_ring->req_cons,
96 rx_ring->req_cons - sring->rsp_prod,
97 sring->req_event,
98 sring->req_event - sring->rsp_prod);
99 seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n\n",
100 sring->rsp_prod,
101 rx_ring->rsp_prod_pvt,
102 rx_ring->rsp_prod_pvt - sring->rsp_prod,
103 sring->rsp_event,
104 sring->rsp_event - sring->rsp_prod);
105 }
106
107 seq_printf(m, "NAPI state: %lx NAPI weight: %d TX queue len %u\n"
108 "Credit timer_pending: %d, credit: %lu, usec: %lu\n"
109 "remaining: %lu, expires: %lu, now: %lu\n",
110 queue->napi.state, queue->napi.weight,
111 skb_queue_len(&queue->tx_queue),
112 timer_pending(&queue->credit_timeout),
113 queue->credit_bytes,
114 queue->credit_usec,
115 queue->remaining_credit,
116 queue->credit_timeout.expires,
117 jiffies);
118
119 dev_queue = netdev_get_tx_queue(queue->vif->dev, queue->id);
120
121 seq_printf(m, "\nRx internal queue: len %u max %u pkts %u %s\n",
122 queue->rx_queue_len, queue->rx_queue_max,
123 skb_queue_len(&queue->rx_queue),
124 netif_tx_queue_stopped(dev_queue) ? "stopped" : "running");
125
126 return 0;
127}
128
129#define XENVIF_KICK_STR "kick"
130#define BUFFER_SIZE 32
131
132static ssize_t
133xenvif_write_io_ring(struct file *filp, const char __user *buf, size_t count,
134 loff_t *ppos)
135{
136 struct xenvif_queue *queue =
137 ((struct seq_file *)filp->private_data)->private;
138 int len;
139 char write[BUFFER_SIZE];
140
141 /* don't allow partial writes and check the length */
142 if (*ppos != 0)
143 return 0;
144 if (count >= sizeof(write))
145 return -ENOSPC;
146
147 len = simple_write_to_buffer(write,
148 sizeof(write) - 1,
149 ppos,
150 buf,
151 count);
152 if (len < 0)
153 return len;
154
155 write[len] = '\0';
156
157 if (!strncmp(write, XENVIF_KICK_STR, sizeof(XENVIF_KICK_STR) - 1))
158 xenvif_interrupt(0, (void *)queue);
159 else {
160 pr_warn("Unknown command to io_ring_q%d. Available: kick\n",
161 queue->id);
162 count = -EINVAL;
163 }
164 return count;
165}
166
167static int xenvif_dump_open(struct inode *inode, struct file *filp)
168{
169 int ret;
170 void *queue = NULL;
171
172 if (inode->i_private)
173 queue = inode->i_private;
174 ret = single_open(filp, xenvif_read_io_ring, queue);
175 filp->f_mode |= FMODE_PWRITE;
176 return ret;
177}
178
179static const struct file_operations xenvif_dbg_io_ring_ops_fops = {
180 .owner = THIS_MODULE,
181 .open = xenvif_dump_open,
182 .read = seq_read,
183 .llseek = seq_lseek,
184 .release = single_release,
185 .write = xenvif_write_io_ring,
186};
187
188static void xenvif_debugfs_addif(struct xenvif *vif)
189{
190 struct dentry *pfile;
191 int i;
192
193 if (IS_ERR_OR_NULL(xen_netback_dbg_root))
194 return;
195
196 vif->xenvif_dbg_root = debugfs_create_dir(vif->dev->name,
197 xen_netback_dbg_root);
198 if (!IS_ERR_OR_NULL(vif->xenvif_dbg_root)) {
199 for (i = 0; i < vif->num_queues; ++i) {
200 char filename[sizeof("io_ring_q") + 4];
201
202 snprintf(filename, sizeof(filename), "io_ring_q%d", i);
203 pfile = debugfs_create_file(filename,
204 S_IRUSR | S_IWUSR,
205 vif->xenvif_dbg_root,
206 &vif->queues[i],
207 &xenvif_dbg_io_ring_ops_fops);
208 if (IS_ERR_OR_NULL(pfile))
209 pr_warn("Creation of io_ring file returned %ld!\n",
210 PTR_ERR(pfile));
211 }
212 } else
213 netdev_warn(vif->dev,
214 "Creation of vif debugfs dir returned %ld!\n",
215 PTR_ERR(vif->xenvif_dbg_root));
216}
217
218static void xenvif_debugfs_delif(struct xenvif *vif)
219{
220 if (IS_ERR_OR_NULL(xen_netback_dbg_root))
221 return;
222
223 if (!IS_ERR_OR_NULL(vif->xenvif_dbg_root))
224 debugfs_remove_recursive(vif->xenvif_dbg_root);
225 vif->xenvif_dbg_root = NULL;
226}
227#endif /* CONFIG_DEBUG_FS */
228
229static int netback_remove(struct xenbus_device *dev)
230{
231 struct backend_info *be = dev_get_drvdata(&dev->dev);
232
233 set_backend_state(be, XenbusStateClosed);
234
235 unregister_hotplug_status_watch(be);
236 if (be->vif) {
237 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
238 xen_unregister_watchers(be->vif);
239 xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
240 xenvif_free(be->vif);
241 be->vif = NULL;
242 }
243 kfree(be->hotplug_script);
244 kfree(be);
245 dev_set_drvdata(&dev->dev, NULL);
246 return 0;
247}
248
249
250/**
251 * Entry point to this code when a new device is created. Allocate the basic
252 * structures and switch to InitWait.
253 */
254static int netback_probe(struct xenbus_device *dev,
255 const struct xenbus_device_id *id)
256{
257 const char *message;
258 struct xenbus_transaction xbt;
259 int err;
260 int sg;
261 const char *script;
262 struct backend_info *be = kzalloc(sizeof(struct backend_info),
263 GFP_KERNEL);
264 if (!be) {
265 xenbus_dev_fatal(dev, -ENOMEM,
266 "allocating backend structure");
267 return -ENOMEM;
268 }
269
270 be->dev = dev;
271 dev_set_drvdata(&dev->dev, be);
272
273 sg = 1;
274
275 do {
276 err = xenbus_transaction_start(&xbt);
277 if (err) {
278 xenbus_dev_fatal(dev, err, "starting transaction");
279 goto fail;
280 }
281
282 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", sg);
283 if (err) {
284 message = "writing feature-sg";
285 goto abort_transaction;
286 }
287
288 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4",
289 "%d", sg);
290 if (err) {
291 message = "writing feature-gso-tcpv4";
292 goto abort_transaction;
293 }
294
295 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv6",
296 "%d", sg);
297 if (err) {
298 message = "writing feature-gso-tcpv6";
299 goto abort_transaction;
300 }
301
302 /* We support partial checksum setup for IPv6 packets */
303 err = xenbus_printf(xbt, dev->nodename,
304 "feature-ipv6-csum-offload",
305 "%d", 1);
306 if (err) {
307 message = "writing feature-ipv6-csum-offload";
308 goto abort_transaction;
309 }
310
311 /* We support rx-copy path. */
312 err = xenbus_printf(xbt, dev->nodename,
313 "feature-rx-copy", "%d", 1);
314 if (err) {
315 message = "writing feature-rx-copy";
316 goto abort_transaction;
317 }
318
319 /*
320 * We don't support rx-flip path (except old guests who don't
321 * grok this feature flag).
322 */
323 err = xenbus_printf(xbt, dev->nodename,
324 "feature-rx-flip", "%d", 0);
325 if (err) {
326 message = "writing feature-rx-flip";
327 goto abort_transaction;
328 }
329
330 /* We support dynamic multicast-control. */
331 err = xenbus_printf(xbt, dev->nodename,
332 "feature-multicast-control", "%d", 1);
333 if (err) {
334 message = "writing feature-multicast-control";
335 goto abort_transaction;
336 }
337
338 err = xenbus_printf(xbt, dev->nodename,
339 "feature-dynamic-multicast-control",
340 "%d", 1);
341 if (err) {
342 message = "writing feature-dynamic-multicast-control";
343 goto abort_transaction;
344 }
345
346 err = xenbus_transaction_end(xbt, 0);
347 } while (err == -EAGAIN);
348
349 if (err) {
350 xenbus_dev_fatal(dev, err, "completing transaction");
351 goto fail;
352 }
353
354 /*
355 * Split event channels support, this is optional so it is not
356 * put inside the above loop.
357 */
358 err = xenbus_printf(XBT_NIL, dev->nodename,
359 "feature-split-event-channels",
360 "%u", separate_tx_rx_irq);
361 if (err)
362 pr_debug("Error writing feature-split-event-channels\n");
363
364 /* Multi-queue support: This is an optional feature. */
365 err = xenbus_printf(XBT_NIL, dev->nodename,
366 "multi-queue-max-queues", "%u", xenvif_max_queues);
367 if (err)
368 pr_debug("Error writing multi-queue-max-queues\n");
369
370 script = xenbus_read(XBT_NIL, dev->nodename, "script", NULL);
371 if (IS_ERR(script)) {
372 err = PTR_ERR(script);
373 xenbus_dev_fatal(dev, err, "reading script");
374 goto fail;
375 }
376
377 be->hotplug_script = script;
378
379 err = xenbus_switch_state(dev, XenbusStateInitWait);
380 if (err)
381 goto fail;
382
383 be->state = XenbusStateInitWait;
384
385 /* This kicks hotplug scripts, so do it immediately. */
386 err = backend_create_xenvif(be);
387 if (err)
388 goto fail;
389
390 return 0;
391
392abort_transaction:
393 xenbus_transaction_end(xbt, 1);
394 xenbus_dev_fatal(dev, err, "%s", message);
395fail:
396 pr_debug("failed\n");
397 netback_remove(dev);
398 return err;
399}
400
401
402/*
403 * Handle the creation of the hotplug script environment. We add the script
404 * and vif variables to the environment, for the benefit of the vif-* hotplug
405 * scripts.
406 */
407static int netback_uevent(struct xenbus_device *xdev,
408 struct kobj_uevent_env *env)
409{
410 struct backend_info *be = dev_get_drvdata(&xdev->dev);
411
412 if (!be)
413 return 0;
414
415 if (add_uevent_var(env, "script=%s", be->hotplug_script))
416 return -ENOMEM;
417
418 if (!be->vif)
419 return 0;
420
421 return add_uevent_var(env, "vif=%s", be->vif->dev->name);
422}
423
424
425static int backend_create_xenvif(struct backend_info *be)
426{
427 int err;
428 long handle;
429 struct xenbus_device *dev = be->dev;
430 struct xenvif *vif;
431
432 if (be->vif != NULL)
433 return 0;
434
435 err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle);
436 if (err != 1) {
437 xenbus_dev_fatal(dev, err, "reading handle");
438 return (err < 0) ? err : -EINVAL;
439 }
440
441 vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle);
442 if (IS_ERR(vif)) {
443 err = PTR_ERR(vif);
444 xenbus_dev_fatal(dev, err, "creating interface");
445 return err;
446 }
447 be->vif = vif;
448
449 kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE);
450 return 0;
451}
452
453static void backend_disconnect(struct backend_info *be)
454{
455 if (be->vif) {
456 xen_unregister_watchers(be->vif);
457#ifdef CONFIG_DEBUG_FS
458 xenvif_debugfs_delif(be->vif);
459#endif /* CONFIG_DEBUG_FS */
460 xenvif_disconnect(be->vif);
461 }
462}
463
464static void backend_connect(struct backend_info *be)
465{
466 if (be->vif)
467 connect(be);
468}
469
470static inline void backend_switch_state(struct backend_info *be,
471 enum xenbus_state state)
472{
473 struct xenbus_device *dev = be->dev;
474
475 pr_debug("%s -> %s\n", dev->nodename, xenbus_strstate(state));
476 be->state = state;
477
478 /* If we are waiting for a hotplug script then defer the
479 * actual xenbus state change.
480 */
481 if (!be->have_hotplug_status_watch)
482 xenbus_switch_state(dev, state);
483}
484
485/* Handle backend state transitions:
486 *
487 * The backend state starts in InitWait and the following transitions are
488 * allowed.
489 *
490 * InitWait -> Connected
491 *
492 * ^ \ |
493 * | \ |
494 * | \ |
495 * | \ |
496 * | \ |
497 * | \ |
498 * | V V
499 *
500 * Closed <-> Closing
501 *
502 * The state argument specifies the eventual state of the backend and the
503 * function transitions to that state via the shortest path.
504 */
505static void set_backend_state(struct backend_info *be,
506 enum xenbus_state state)
507{
508 while (be->state != state) {
509 switch (be->state) {
510 case XenbusStateClosed:
511 switch (state) {
512 case XenbusStateInitWait:
513 case XenbusStateConnected:
514 backend_switch_state(be, XenbusStateInitWait);
515 break;
516 case XenbusStateClosing:
517 backend_switch_state(be, XenbusStateClosing);
518 break;
519 default:
520 BUG();
521 }
522 break;
523 case XenbusStateInitWait:
524 switch (state) {
525 case XenbusStateConnected:
526 backend_connect(be);
527 backend_switch_state(be, XenbusStateConnected);
528 break;
529 case XenbusStateClosing:
530 case XenbusStateClosed:
531 backend_switch_state(be, XenbusStateClosing);
532 break;
533 default:
534 BUG();
535 }
536 break;
537 case XenbusStateConnected:
538 switch (state) {
539 case XenbusStateInitWait:
540 case XenbusStateClosing:
541 case XenbusStateClosed:
542 backend_disconnect(be);
543 backend_switch_state(be, XenbusStateClosing);
544 break;
545 default:
546 BUG();
547 }
548 break;
549 case XenbusStateClosing:
550 switch (state) {
551 case XenbusStateInitWait:
552 case XenbusStateConnected:
553 case XenbusStateClosed:
554 backend_switch_state(be, XenbusStateClosed);
555 break;
556 default:
557 BUG();
558 }
559 break;
560 default:
561 BUG();
562 }
563 }
564}
565
566/**
567 * Callback received when the frontend's state changes.
568 */
569static void frontend_changed(struct xenbus_device *dev,
570 enum xenbus_state frontend_state)
571{
572 struct backend_info *be = dev_get_drvdata(&dev->dev);
573
574 pr_debug("%s -> %s\n", dev->otherend, xenbus_strstate(frontend_state));
575
576 be->frontend_state = frontend_state;
577
578 switch (frontend_state) {
579 case XenbusStateInitialising:
580 set_backend_state(be, XenbusStateInitWait);
581 break;
582
583 case XenbusStateInitialised:
584 break;
585
586 case XenbusStateConnected:
587 set_backend_state(be, XenbusStateConnected);
588 break;
589
590 case XenbusStateClosing:
591 set_backend_state(be, XenbusStateClosing);
592 break;
593
594 case XenbusStateClosed:
595 set_backend_state(be, XenbusStateClosed);
596 if (xenbus_dev_is_online(dev))
597 break;
598 /* fall through if not online */
599 case XenbusStateUnknown:
600 set_backend_state(be, XenbusStateClosed);
601 device_unregister(&dev->dev);
602 break;
603
604 default:
605 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
606 frontend_state);
607 break;
608 }
609}
610
611
612static void xen_net_read_rate(struct xenbus_device *dev,
613 unsigned long *bytes, unsigned long *usec)
614{
615 char *s, *e;
616 unsigned long b, u;
617 char *ratestr;
618
619 /* Default to unlimited bandwidth. */
620 *bytes = ~0UL;
621 *usec = 0;
622
623 ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL);
624 if (IS_ERR(ratestr))
625 return;
626
627 s = ratestr;
628 b = simple_strtoul(s, &e, 10);
629 if ((s == e) || (*e != ','))
630 goto fail;
631
632 s = e + 1;
633 u = simple_strtoul(s, &e, 10);
634 if ((s == e) || (*e != '\0'))
635 goto fail;
636
637 *bytes = b;
638 *usec = u;
639
640 kfree(ratestr);
641 return;
642
643 fail:
644 pr_warn("Failed to parse network rate limit. Traffic unlimited.\n");
645 kfree(ratestr);
646}
647
648static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
649{
650 char *s, *e, *macstr;
651 int i;
652
653 macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
654 if (IS_ERR(macstr))
655 return PTR_ERR(macstr);
656
657 for (i = 0; i < ETH_ALEN; i++) {
658 mac[i] = simple_strtoul(s, &e, 16);
659 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
660 kfree(macstr);
661 return -ENOENT;
662 }
663 s = e+1;
664 }
665
666 kfree(macstr);
667 return 0;
668}
669
670static void xen_net_rate_changed(struct xenbus_watch *watch,
671 const char **vec, unsigned int len)
672{
673 struct xenvif *vif = container_of(watch, struct xenvif, credit_watch);
674 struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
675 unsigned long credit_bytes;
676 unsigned long credit_usec;
677 unsigned int queue_index;
678
679 xen_net_read_rate(dev, &credit_bytes, &credit_usec);
680 for (queue_index = 0; queue_index < vif->num_queues; queue_index++) {
681 struct xenvif_queue *queue = &vif->queues[queue_index];
682
683 queue->credit_bytes = credit_bytes;
684 queue->credit_usec = credit_usec;
685 if (!mod_timer_pending(&queue->credit_timeout, jiffies) &&
686 queue->remaining_credit > queue->credit_bytes) {
687 queue->remaining_credit = queue->credit_bytes;
688 }
689 }
690}
691
692static int xen_register_credit_watch(struct xenbus_device *dev,
693 struct xenvif *vif)
694{
695 int err = 0;
696 char *node;
697 unsigned maxlen = strlen(dev->nodename) + sizeof("/rate");
698
699 if (vif->credit_watch.node)
700 return -EADDRINUSE;
701
702 node = kmalloc(maxlen, GFP_KERNEL);
703 if (!node)
704 return -ENOMEM;
705 snprintf(node, maxlen, "%s/rate", dev->nodename);
706 vif->credit_watch.node = node;
707 vif->credit_watch.callback = xen_net_rate_changed;
708 err = register_xenbus_watch(&vif->credit_watch);
709 if (err) {
710 pr_err("Failed to set watcher %s\n", vif->credit_watch.node);
711 kfree(node);
712 vif->credit_watch.node = NULL;
713 vif->credit_watch.callback = NULL;
714 }
715 return err;
716}
717
718static void xen_unregister_credit_watch(struct xenvif *vif)
719{
720 if (vif->credit_watch.node) {
721 unregister_xenbus_watch(&vif->credit_watch);
722 kfree(vif->credit_watch.node);
723 vif->credit_watch.node = NULL;
724 }
725}
726
727static void xen_mcast_ctrl_changed(struct xenbus_watch *watch,
728 const char **vec, unsigned int len)
729{
730 struct xenvif *vif = container_of(watch, struct xenvif,
731 mcast_ctrl_watch);
732 struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
733 int val;
734
735 if (xenbus_scanf(XBT_NIL, dev->otherend,
736 "request-multicast-control", "%d", &val) < 0)
737 val = 0;
738 vif->multicast_control = !!val;
739}
740
741static int xen_register_mcast_ctrl_watch(struct xenbus_device *dev,
742 struct xenvif *vif)
743{
744 int err = 0;
745 char *node;
746 unsigned maxlen = strlen(dev->otherend) +
747 sizeof("/request-multicast-control");
748
749 if (vif->mcast_ctrl_watch.node) {
750 pr_err_ratelimited("Watch is already registered\n");
751 return -EADDRINUSE;
752 }
753
754 node = kmalloc(maxlen, GFP_KERNEL);
755 if (!node) {
756 pr_err("Failed to allocate memory for watch\n");
757 return -ENOMEM;
758 }
759 snprintf(node, maxlen, "%s/request-multicast-control",
760 dev->otherend);
761 vif->mcast_ctrl_watch.node = node;
762 vif->mcast_ctrl_watch.callback = xen_mcast_ctrl_changed;
763 err = register_xenbus_watch(&vif->mcast_ctrl_watch);
764 if (err) {
765 pr_err("Failed to set watcher %s\n",
766 vif->mcast_ctrl_watch.node);
767 kfree(node);
768 vif->mcast_ctrl_watch.node = NULL;
769 vif->mcast_ctrl_watch.callback = NULL;
770 }
771 return err;
772}
773
774static void xen_unregister_mcast_ctrl_watch(struct xenvif *vif)
775{
776 if (vif->mcast_ctrl_watch.node) {
777 unregister_xenbus_watch(&vif->mcast_ctrl_watch);
778 kfree(vif->mcast_ctrl_watch.node);
779 vif->mcast_ctrl_watch.node = NULL;
780 }
781}
782
783static void xen_register_watchers(struct xenbus_device *dev,
784 struct xenvif *vif)
785{
786 xen_register_credit_watch(dev, vif);
787 xen_register_mcast_ctrl_watch(dev, vif);
788}
789
790static void xen_unregister_watchers(struct xenvif *vif)
791{
792 xen_unregister_mcast_ctrl_watch(vif);
793 xen_unregister_credit_watch(vif);
794}
795
796static void unregister_hotplug_status_watch(struct backend_info *be)
797{
798 if (be->have_hotplug_status_watch) {
799 unregister_xenbus_watch(&be->hotplug_status_watch);
800 kfree(be->hotplug_status_watch.node);
801 }
802 be->have_hotplug_status_watch = 0;
803}
804
805static void hotplug_status_changed(struct xenbus_watch *watch,
806 const char **vec,
807 unsigned int vec_size)
808{
809 struct backend_info *be = container_of(watch,
810 struct backend_info,
811 hotplug_status_watch);
812 char *str;
813 unsigned int len;
814
815 str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len);
816 if (IS_ERR(str))
817 return;
818 if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) {
819 /* Complete any pending state change */
820 xenbus_switch_state(be->dev, be->state);
821
822 /* Not interested in this watch anymore. */
823 unregister_hotplug_status_watch(be);
824 }
825 kfree(str);
826}
827
828static void connect(struct backend_info *be)
829{
830 int err;
831 struct xenbus_device *dev = be->dev;
832 unsigned long credit_bytes, credit_usec;
833 unsigned int queue_index;
834 unsigned int requested_num_queues;
835 struct xenvif_queue *queue;
836
837 /* Check whether the frontend requested multiple queues
838 * and read the number requested.
839 */
840 err = xenbus_scanf(XBT_NIL, dev->otherend,
841 "multi-queue-num-queues",
842 "%u", &requested_num_queues);
843 if (err < 0) {
844 requested_num_queues = 1; /* Fall back to single queue */
845 } else if (requested_num_queues > xenvif_max_queues) {
846 /* buggy or malicious guest */
847 xenbus_dev_fatal(dev, err,
848 "guest requested %u queues, exceeding the maximum of %u.",
849 requested_num_queues, xenvif_max_queues);
850 return;
851 }
852
853 err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
854 if (err) {
855 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
856 return;
857 }
858
859 xen_net_read_rate(dev, &credit_bytes, &credit_usec);
860 xen_unregister_watchers(be->vif);
861 xen_register_watchers(dev, be->vif);
862 read_xenbus_vif_flags(be);
863
864 /* Use the number of queues requested by the frontend */
865 be->vif->queues = vzalloc(requested_num_queues *
866 sizeof(struct xenvif_queue));
867 if (!be->vif->queues) {
868 xenbus_dev_fatal(dev, -ENOMEM,
869 "allocating queues");
870 return;
871 }
872
873 be->vif->num_queues = requested_num_queues;
874 be->vif->stalled_queues = requested_num_queues;
875
876 for (queue_index = 0; queue_index < requested_num_queues; ++queue_index) {
877 queue = &be->vif->queues[queue_index];
878 queue->vif = be->vif;
879 queue->id = queue_index;
880 snprintf(queue->name, sizeof(queue->name), "%s-q%u",
881 be->vif->dev->name, queue->id);
882
883 err = xenvif_init_queue(queue);
884 if (err) {
885 /* xenvif_init_queue() cleans up after itself on
886 * failure, but we need to clean up any previously
887 * initialised queues. Set num_queues to i so that
888 * earlier queues can be destroyed using the regular
889 * disconnect logic.
890 */
891 be->vif->num_queues = queue_index;
892 goto err;
893 }
894
895 queue->credit_bytes = credit_bytes;
896 queue->remaining_credit = credit_bytes;
897 queue->credit_usec = credit_usec;
898
899 err = connect_rings(be, queue);
900 if (err) {
901 /* connect_rings() cleans up after itself on failure,
902 * but we need to clean up after xenvif_init_queue() here,
903 * and also clean up any previously initialised queues.
904 */
905 xenvif_deinit_queue(queue);
906 be->vif->num_queues = queue_index;
907 goto err;
908 }
909 }
910
911#ifdef CONFIG_DEBUG_FS
912 xenvif_debugfs_addif(be->vif);
913#endif /* CONFIG_DEBUG_FS */
914
915 /* Initialisation completed, tell core driver the number of
916 * active queues.
917 */
918 rtnl_lock();
919 netif_set_real_num_tx_queues(be->vif->dev, requested_num_queues);
920 netif_set_real_num_rx_queues(be->vif->dev, requested_num_queues);
921 rtnl_unlock();
922
923 xenvif_carrier_on(be->vif);
924
925 unregister_hotplug_status_watch(be);
926 err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
927 hotplug_status_changed,
928 "%s/%s", dev->nodename, "hotplug-status");
929 if (!err)
930 be->have_hotplug_status_watch = 1;
931
932 netif_tx_wake_all_queues(be->vif->dev);
933
934 return;
935
936err:
937 if (be->vif->num_queues > 0)
938 xenvif_disconnect(be->vif); /* Clean up existing queues */
939 vfree(be->vif->queues);
940 be->vif->queues = NULL;
941 be->vif->num_queues = 0;
942 return;
943}
944
945
946static int connect_rings(struct backend_info *be, struct xenvif_queue *queue)
947{
948 struct xenbus_device *dev = be->dev;
949 unsigned int num_queues = queue->vif->num_queues;
950 unsigned long tx_ring_ref, rx_ring_ref;
951 unsigned int tx_evtchn, rx_evtchn;
952 int err;
953 char *xspath;
954 size_t xspathsize;
955 const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */
956
957 /* If the frontend requested 1 queue, or we have fallen back
958 * to single queue due to lack of frontend support for multi-
959 * queue, expect the remaining XenStore keys in the toplevel
960 * directory. Otherwise, expect them in a subdirectory called
961 * queue-N.
962 */
963 if (num_queues == 1) {
964 xspath = kzalloc(strlen(dev->otherend) + 1, GFP_KERNEL);
965 if (!xspath) {
966 xenbus_dev_fatal(dev, -ENOMEM,
967 "reading ring references");
968 return -ENOMEM;
969 }
970 strcpy(xspath, dev->otherend);
971 } else {
972 xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
973 xspath = kzalloc(xspathsize, GFP_KERNEL);
974 if (!xspath) {
975 xenbus_dev_fatal(dev, -ENOMEM,
976 "reading ring references");
977 return -ENOMEM;
978 }
979 snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend,
980 queue->id);
981 }
982
983 err = xenbus_gather(XBT_NIL, xspath,
984 "tx-ring-ref", "%lu", &tx_ring_ref,
985 "rx-ring-ref", "%lu", &rx_ring_ref, NULL);
986 if (err) {
987 xenbus_dev_fatal(dev, err,
988 "reading %s/ring-ref",
989 xspath);
990 goto err;
991 }
992
993 /* Try split event channels first, then single event channel. */
994 err = xenbus_gather(XBT_NIL, xspath,
995 "event-channel-tx", "%u", &tx_evtchn,
996 "event-channel-rx", "%u", &rx_evtchn, NULL);
997 if (err < 0) {
998 err = xenbus_scanf(XBT_NIL, xspath,
999 "event-channel", "%u", &tx_evtchn);
1000 if (err < 0) {
1001 xenbus_dev_fatal(dev, err,
1002 "reading %s/event-channel(-tx/rx)",
1003 xspath);
1004 goto err;
1005 }
1006 rx_evtchn = tx_evtchn;
1007 }
1008
1009 /* Map the shared frame, irq etc. */
1010 err = xenvif_connect(queue, tx_ring_ref, rx_ring_ref,
1011 tx_evtchn, rx_evtchn);
1012 if (err) {
1013 xenbus_dev_fatal(dev, err,
1014 "mapping shared-frames %lu/%lu port tx %u rx %u",
1015 tx_ring_ref, rx_ring_ref,
1016 tx_evtchn, rx_evtchn);
1017 goto err;
1018 }
1019
1020 err = 0;
1021err: /* Regular return falls through with err == 0 */
1022 kfree(xspath);
1023 return err;
1024}
1025
1026static int read_xenbus_vif_flags(struct backend_info *be)
1027{
1028 struct xenvif *vif = be->vif;
1029 struct xenbus_device *dev = be->dev;
1030 unsigned int rx_copy;
1031 int err, val;
1032
1033 err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
1034 &rx_copy);
1035 if (err == -ENOENT) {
1036 err = 0;
1037 rx_copy = 0;
1038 }
1039 if (err < 0) {
1040 xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy",
1041 dev->otherend);
1042 return err;
1043 }
1044 if (!rx_copy)
1045 return -EOPNOTSUPP;
1046
1047 if (xenbus_scanf(XBT_NIL, dev->otherend,
1048 "feature-rx-notify", "%d", &val) < 0)
1049 val = 0;
1050 if (!val) {
1051 /* - Reduce drain timeout to poll more frequently for
1052 * Rx requests.
1053 * - Disable Rx stall detection.
1054 */
1055 be->vif->drain_timeout = msecs_to_jiffies(30);
1056 be->vif->stall_timeout = 0;
1057 }
1058
1059 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg",
1060 "%d", &val) < 0)
1061 val = 0;
1062 vif->can_sg = !!val;
1063
1064 vif->gso_mask = 0;
1065 vif->gso_prefix_mask = 0;
1066
1067 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4",
1068 "%d", &val) < 0)
1069 val = 0;
1070 if (val)
1071 vif->gso_mask |= GSO_BIT(TCPV4);
1072
1073 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4-prefix",
1074 "%d", &val) < 0)
1075 val = 0;
1076 if (val)
1077 vif->gso_prefix_mask |= GSO_BIT(TCPV4);
1078
1079 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv6",
1080 "%d", &val) < 0)
1081 val = 0;
1082 if (val)
1083 vif->gso_mask |= GSO_BIT(TCPV6);
1084
1085 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv6-prefix",
1086 "%d", &val) < 0)
1087 val = 0;
1088 if (val)
1089 vif->gso_prefix_mask |= GSO_BIT(TCPV6);
1090
1091 if (vif->gso_mask & vif->gso_prefix_mask) {
1092 xenbus_dev_fatal(dev, err,
1093 "%s: gso and gso prefix flags are not "
1094 "mutually exclusive",
1095 dev->otherend);
1096 return -EOPNOTSUPP;
1097 }
1098
1099 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload",
1100 "%d", &val) < 0)
1101 val = 0;
1102 vif->ip_csum = !val;
1103
1104 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-ipv6-csum-offload",
1105 "%d", &val) < 0)
1106 val = 0;
1107 vif->ipv6_csum = !!val;
1108
1109 return 0;
1110}
1111
1112static const struct xenbus_device_id netback_ids[] = {
1113 { "vif" },
1114 { "" }
1115};
1116
1117static struct xenbus_driver netback_driver = {
1118 .ids = netback_ids,
1119 .probe = netback_probe,
1120 .remove = netback_remove,
1121 .uevent = netback_uevent,
1122 .otherend_changed = frontend_changed,
1123};
1124
1125int xenvif_xenbus_init(void)
1126{
1127 return xenbus_register_backend(&netback_driver);
1128}
1129
1130void xenvif_xenbus_fini(void)
1131{
1132 return xenbus_unregister_driver(&netback_driver);
1133}