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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 0600,
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 0400,
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 struct xenvif *vif = be->vif;
496
497 if (vif) {
498 unsigned int num_queues = vif->num_queues;
499 unsigned int queue_index;
500
501 xen_unregister_watchers(vif);
502#ifdef CONFIG_DEBUG_FS
503 xenvif_debugfs_delif(vif);
504#endif /* CONFIG_DEBUG_FS */
505 xenvif_disconnect_data(vif);
506
507 /* At this point some of the handlers may still be active
508 * so we need to have additional synchronization here.
509 */
510 vif->num_queues = 0;
511 synchronize_net();
512
513 for (queue_index = 0; queue_index < num_queues; ++queue_index)
514 xenvif_deinit_queue(&vif->queues[queue_index]);
515
516 vfree(vif->queues);
517 vif->queues = NULL;
518
519 xenvif_disconnect_ctrl(vif);
520 }
521}
522
523static void backend_connect(struct backend_info *be)
524{
525 if (be->vif)
526 connect(be);
527}
528
529static inline void backend_switch_state(struct backend_info *be,
530 enum xenbus_state state)
531{
532 struct xenbus_device *dev = be->dev;
533
534 pr_debug("%s -> %s\n", dev->nodename, xenbus_strstate(state));
535 be->state = state;
536
537 /* If we are waiting for a hotplug script then defer the
538 * actual xenbus state change.
539 */
540 if (!be->have_hotplug_status_watch)
541 xenbus_switch_state(dev, state);
542}
543
544/* Handle backend state transitions:
545 *
546 * The backend state starts in Initialising and the following transitions are
547 * allowed.
548 *
549 * Initialising -> InitWait -> Connected
550 * \
551 * \ ^ \ |
552 * \ | \ |
553 * \ | \ |
554 * \ | \ |
555 * \ | \ |
556 * \ | \ |
557 * V | V V
558 *
559 * Closed <-> Closing
560 *
561 * The state argument specifies the eventual state of the backend and the
562 * function transitions to that state via the shortest path.
563 */
564static void set_backend_state(struct backend_info *be,
565 enum xenbus_state state)
566{
567 while (be->state != state) {
568 switch (be->state) {
569 case XenbusStateInitialising:
570 switch (state) {
571 case XenbusStateInitWait:
572 case XenbusStateConnected:
573 case XenbusStateClosing:
574 backend_switch_state(be, XenbusStateInitWait);
575 break;
576 case XenbusStateClosed:
577 backend_switch_state(be, XenbusStateClosed);
578 break;
579 default:
580 BUG();
581 }
582 break;
583 case XenbusStateClosed:
584 switch (state) {
585 case XenbusStateInitWait:
586 case XenbusStateConnected:
587 backend_switch_state(be, XenbusStateInitWait);
588 break;
589 case XenbusStateClosing:
590 backend_switch_state(be, XenbusStateClosing);
591 break;
592 default:
593 BUG();
594 }
595 break;
596 case XenbusStateInitWait:
597 switch (state) {
598 case XenbusStateConnected:
599 backend_connect(be);
600 backend_switch_state(be, XenbusStateConnected);
601 break;
602 case XenbusStateClosing:
603 case XenbusStateClosed:
604 backend_switch_state(be, XenbusStateClosing);
605 break;
606 default:
607 BUG();
608 }
609 break;
610 case XenbusStateConnected:
611 switch (state) {
612 case XenbusStateInitWait:
613 case XenbusStateClosing:
614 case XenbusStateClosed:
615 backend_disconnect(be);
616 backend_switch_state(be, XenbusStateClosing);
617 break;
618 default:
619 BUG();
620 }
621 break;
622 case XenbusStateClosing:
623 switch (state) {
624 case XenbusStateInitWait:
625 case XenbusStateConnected:
626 case XenbusStateClosed:
627 backend_switch_state(be, XenbusStateClosed);
628 break;
629 default:
630 BUG();
631 }
632 break;
633 default:
634 BUG();
635 }
636 }
637}
638
639/**
640 * Callback received when the frontend's state changes.
641 */
642static void frontend_changed(struct xenbus_device *dev,
643 enum xenbus_state frontend_state)
644{
645 struct backend_info *be = dev_get_drvdata(&dev->dev);
646
647 pr_debug("%s -> %s\n", dev->otherend, xenbus_strstate(frontend_state));
648
649 be->frontend_state = frontend_state;
650
651 switch (frontend_state) {
652 case XenbusStateInitialising:
653 set_backend_state(be, XenbusStateInitWait);
654 break;
655
656 case XenbusStateInitialised:
657 break;
658
659 case XenbusStateConnected:
660 set_backend_state(be, XenbusStateConnected);
661 break;
662
663 case XenbusStateClosing:
664 set_backend_state(be, XenbusStateClosing);
665 break;
666
667 case XenbusStateClosed:
668 set_backend_state(be, XenbusStateClosed);
669 if (xenbus_dev_is_online(dev))
670 break;
671 /* fall through if not online */
672 case XenbusStateUnknown:
673 set_backend_state(be, XenbusStateClosed);
674 device_unregister(&dev->dev);
675 break;
676
677 default:
678 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
679 frontend_state);
680 break;
681 }
682}
683
684
685static void xen_net_read_rate(struct xenbus_device *dev,
686 unsigned long *bytes, unsigned long *usec)
687{
688 char *s, *e;
689 unsigned long b, u;
690 char *ratestr;
691
692 /* Default to unlimited bandwidth. */
693 *bytes = ~0UL;
694 *usec = 0;
695
696 ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL);
697 if (IS_ERR(ratestr))
698 return;
699
700 s = ratestr;
701 b = simple_strtoul(s, &e, 10);
702 if ((s == e) || (*e != ','))
703 goto fail;
704
705 s = e + 1;
706 u = simple_strtoul(s, &e, 10);
707 if ((s == e) || (*e != '\0'))
708 goto fail;
709
710 *bytes = b;
711 *usec = u;
712
713 kfree(ratestr);
714 return;
715
716 fail:
717 pr_warn("Failed to parse network rate limit. Traffic unlimited.\n");
718 kfree(ratestr);
719}
720
721static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
722{
723 char *s, *e, *macstr;
724 int i;
725
726 macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
727 if (IS_ERR(macstr))
728 return PTR_ERR(macstr);
729
730 for (i = 0; i < ETH_ALEN; i++) {
731 mac[i] = simple_strtoul(s, &e, 16);
732 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
733 kfree(macstr);
734 return -ENOENT;
735 }
736 s = e+1;
737 }
738
739 kfree(macstr);
740 return 0;
741}
742
743static void xen_net_rate_changed(struct xenbus_watch *watch,
744 const char *path, const char *token)
745{
746 struct xenvif *vif = container_of(watch, struct xenvif, credit_watch);
747 struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
748 unsigned long credit_bytes;
749 unsigned long credit_usec;
750 unsigned int queue_index;
751
752 xen_net_read_rate(dev, &credit_bytes, &credit_usec);
753 for (queue_index = 0; queue_index < vif->num_queues; queue_index++) {
754 struct xenvif_queue *queue = &vif->queues[queue_index];
755
756 queue->credit_bytes = credit_bytes;
757 queue->credit_usec = credit_usec;
758 if (!mod_timer_pending(&queue->credit_timeout, jiffies) &&
759 queue->remaining_credit > queue->credit_bytes) {
760 queue->remaining_credit = queue->credit_bytes;
761 }
762 }
763}
764
765static int xen_register_credit_watch(struct xenbus_device *dev,
766 struct xenvif *vif)
767{
768 int err = 0;
769 char *node;
770 unsigned maxlen = strlen(dev->nodename) + sizeof("/rate");
771
772 if (vif->credit_watch.node)
773 return -EADDRINUSE;
774
775 node = kmalloc(maxlen, GFP_KERNEL);
776 if (!node)
777 return -ENOMEM;
778 snprintf(node, maxlen, "%s/rate", dev->nodename);
779 vif->credit_watch.node = node;
780 vif->credit_watch.callback = xen_net_rate_changed;
781 err = register_xenbus_watch(&vif->credit_watch);
782 if (err) {
783 pr_err("Failed to set watcher %s\n", vif->credit_watch.node);
784 kfree(node);
785 vif->credit_watch.node = NULL;
786 vif->credit_watch.callback = NULL;
787 }
788 return err;
789}
790
791static void xen_unregister_credit_watch(struct xenvif *vif)
792{
793 if (vif->credit_watch.node) {
794 unregister_xenbus_watch(&vif->credit_watch);
795 kfree(vif->credit_watch.node);
796 vif->credit_watch.node = NULL;
797 }
798}
799
800static void xen_mcast_ctrl_changed(struct xenbus_watch *watch,
801 const char *path, const char *token)
802{
803 struct xenvif *vif = container_of(watch, struct xenvif,
804 mcast_ctrl_watch);
805 struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
806
807 vif->multicast_control = !!xenbus_read_unsigned(dev->otherend,
808 "request-multicast-control", 0);
809}
810
811static int xen_register_mcast_ctrl_watch(struct xenbus_device *dev,
812 struct xenvif *vif)
813{
814 int err = 0;
815 char *node;
816 unsigned maxlen = strlen(dev->otherend) +
817 sizeof("/request-multicast-control");
818
819 if (vif->mcast_ctrl_watch.node) {
820 pr_err_ratelimited("Watch is already registered\n");
821 return -EADDRINUSE;
822 }
823
824 node = kmalloc(maxlen, GFP_KERNEL);
825 if (!node) {
826 pr_err("Failed to allocate memory for watch\n");
827 return -ENOMEM;
828 }
829 snprintf(node, maxlen, "%s/request-multicast-control",
830 dev->otherend);
831 vif->mcast_ctrl_watch.node = node;
832 vif->mcast_ctrl_watch.callback = xen_mcast_ctrl_changed;
833 err = register_xenbus_watch(&vif->mcast_ctrl_watch);
834 if (err) {
835 pr_err("Failed to set watcher %s\n",
836 vif->mcast_ctrl_watch.node);
837 kfree(node);
838 vif->mcast_ctrl_watch.node = NULL;
839 vif->mcast_ctrl_watch.callback = NULL;
840 }
841 return err;
842}
843
844static void xen_unregister_mcast_ctrl_watch(struct xenvif *vif)
845{
846 if (vif->mcast_ctrl_watch.node) {
847 unregister_xenbus_watch(&vif->mcast_ctrl_watch);
848 kfree(vif->mcast_ctrl_watch.node);
849 vif->mcast_ctrl_watch.node = NULL;
850 }
851}
852
853static void xen_register_watchers(struct xenbus_device *dev,
854 struct xenvif *vif)
855{
856 xen_register_credit_watch(dev, vif);
857 xen_register_mcast_ctrl_watch(dev, vif);
858}
859
860static void xen_unregister_watchers(struct xenvif *vif)
861{
862 xen_unregister_mcast_ctrl_watch(vif);
863 xen_unregister_credit_watch(vif);
864}
865
866static void unregister_hotplug_status_watch(struct backend_info *be)
867{
868 if (be->have_hotplug_status_watch) {
869 unregister_xenbus_watch(&be->hotplug_status_watch);
870 kfree(be->hotplug_status_watch.node);
871 }
872 be->have_hotplug_status_watch = 0;
873}
874
875static void hotplug_status_changed(struct xenbus_watch *watch,
876 const char *path,
877 const char *token)
878{
879 struct backend_info *be = container_of(watch,
880 struct backend_info,
881 hotplug_status_watch);
882 char *str;
883 unsigned int len;
884
885 str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len);
886 if (IS_ERR(str))
887 return;
888 if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) {
889 /* Complete any pending state change */
890 xenbus_switch_state(be->dev, be->state);
891
892 /* Not interested in this watch anymore. */
893 unregister_hotplug_status_watch(be);
894 }
895 kfree(str);
896}
897
898static int connect_ctrl_ring(struct backend_info *be)
899{
900 struct xenbus_device *dev = be->dev;
901 struct xenvif *vif = be->vif;
902 unsigned int val;
903 grant_ref_t ring_ref;
904 unsigned int evtchn;
905 int err;
906
907 err = xenbus_scanf(XBT_NIL, dev->otherend,
908 "ctrl-ring-ref", "%u", &val);
909 if (err < 0)
910 goto done; /* The frontend does not have a control ring */
911
912 ring_ref = val;
913
914 err = xenbus_scanf(XBT_NIL, dev->otherend,
915 "event-channel-ctrl", "%u", &val);
916 if (err < 0) {
917 xenbus_dev_fatal(dev, err,
918 "reading %s/event-channel-ctrl",
919 dev->otherend);
920 goto fail;
921 }
922
923 evtchn = val;
924
925 err = xenvif_connect_ctrl(vif, ring_ref, evtchn);
926 if (err) {
927 xenbus_dev_fatal(dev, err,
928 "mapping shared-frame %u port %u",
929 ring_ref, evtchn);
930 goto fail;
931 }
932
933done:
934 return 0;
935
936fail:
937 return err;
938}
939
940static void connect(struct backend_info *be)
941{
942 int err;
943 struct xenbus_device *dev = be->dev;
944 unsigned long credit_bytes, credit_usec;
945 unsigned int queue_index;
946 unsigned int requested_num_queues;
947 struct xenvif_queue *queue;
948
949 /* Check whether the frontend requested multiple queues
950 * and read the number requested.
951 */
952 requested_num_queues = xenbus_read_unsigned(dev->otherend,
953 "multi-queue-num-queues", 1);
954 if (requested_num_queues > xenvif_max_queues) {
955 /* buggy or malicious guest */
956 xenbus_dev_fatal(dev, -EINVAL,
957 "guest requested %u queues, exceeding the maximum of %u.",
958 requested_num_queues, xenvif_max_queues);
959 return;
960 }
961
962 err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
963 if (err) {
964 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
965 return;
966 }
967
968 xen_net_read_rate(dev, &credit_bytes, &credit_usec);
969 xen_unregister_watchers(be->vif);
970 xen_register_watchers(dev, be->vif);
971 read_xenbus_vif_flags(be);
972
973 err = connect_ctrl_ring(be);
974 if (err) {
975 xenbus_dev_fatal(dev, err, "connecting control ring");
976 return;
977 }
978
979 /* Use the number of queues requested by the frontend */
980 be->vif->queues = vzalloc(requested_num_queues *
981 sizeof(struct xenvif_queue));
982 if (!be->vif->queues) {
983 xenbus_dev_fatal(dev, -ENOMEM,
984 "allocating queues");
985 return;
986 }
987
988 be->vif->num_queues = requested_num_queues;
989 be->vif->stalled_queues = requested_num_queues;
990
991 for (queue_index = 0; queue_index < requested_num_queues; ++queue_index) {
992 queue = &be->vif->queues[queue_index];
993 queue->vif = be->vif;
994 queue->id = queue_index;
995 snprintf(queue->name, sizeof(queue->name), "%s-q%u",
996 be->vif->dev->name, queue->id);
997
998 err = xenvif_init_queue(queue);
999 if (err) {
1000 /* xenvif_init_queue() cleans up after itself on
1001 * failure, but we need to clean up any previously
1002 * initialised queues. Set num_queues to i so that
1003 * earlier queues can be destroyed using the regular
1004 * disconnect logic.
1005 */
1006 be->vif->num_queues = queue_index;
1007 goto err;
1008 }
1009
1010 queue->credit_bytes = credit_bytes;
1011 queue->remaining_credit = credit_bytes;
1012 queue->credit_usec = credit_usec;
1013
1014 err = connect_data_rings(be, queue);
1015 if (err) {
1016 /* connect_data_rings() cleans up after itself on
1017 * failure, but we need to clean up after
1018 * xenvif_init_queue() here, and also clean up any
1019 * previously initialised queues.
1020 */
1021 xenvif_deinit_queue(queue);
1022 be->vif->num_queues = queue_index;
1023 goto err;
1024 }
1025 }
1026
1027#ifdef CONFIG_DEBUG_FS
1028 xenvif_debugfs_addif(be->vif);
1029#endif /* CONFIG_DEBUG_FS */
1030
1031 /* Initialisation completed, tell core driver the number of
1032 * active queues.
1033 */
1034 rtnl_lock();
1035 netif_set_real_num_tx_queues(be->vif->dev, requested_num_queues);
1036 netif_set_real_num_rx_queues(be->vif->dev, requested_num_queues);
1037 rtnl_unlock();
1038
1039 xenvif_carrier_on(be->vif);
1040
1041 unregister_hotplug_status_watch(be);
1042 err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
1043 hotplug_status_changed,
1044 "%s/%s", dev->nodename, "hotplug-status");
1045 if (!err)
1046 be->have_hotplug_status_watch = 1;
1047
1048 netif_tx_wake_all_queues(be->vif->dev);
1049
1050 return;
1051
1052err:
1053 if (be->vif->num_queues > 0)
1054 xenvif_disconnect_data(be->vif); /* Clean up existing queues */
1055 for (queue_index = 0; queue_index < be->vif->num_queues; ++queue_index)
1056 xenvif_deinit_queue(&be->vif->queues[queue_index]);
1057 vfree(be->vif->queues);
1058 be->vif->queues = NULL;
1059 be->vif->num_queues = 0;
1060 xenvif_disconnect_ctrl(be->vif);
1061 return;
1062}
1063
1064
1065static int connect_data_rings(struct backend_info *be,
1066 struct xenvif_queue *queue)
1067{
1068 struct xenbus_device *dev = be->dev;
1069 unsigned int num_queues = queue->vif->num_queues;
1070 unsigned long tx_ring_ref, rx_ring_ref;
1071 unsigned int tx_evtchn, rx_evtchn;
1072 int err;
1073 char *xspath;
1074 size_t xspathsize;
1075 const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */
1076
1077 /* If the frontend requested 1 queue, or we have fallen back
1078 * to single queue due to lack of frontend support for multi-
1079 * queue, expect the remaining XenStore keys in the toplevel
1080 * directory. Otherwise, expect them in a subdirectory called
1081 * queue-N.
1082 */
1083 if (num_queues == 1) {
1084 xspath = kzalloc(strlen(dev->otherend) + 1, GFP_KERNEL);
1085 if (!xspath) {
1086 xenbus_dev_fatal(dev, -ENOMEM,
1087 "reading ring references");
1088 return -ENOMEM;
1089 }
1090 strcpy(xspath, dev->otherend);
1091 } else {
1092 xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
1093 xspath = kzalloc(xspathsize, GFP_KERNEL);
1094 if (!xspath) {
1095 xenbus_dev_fatal(dev, -ENOMEM,
1096 "reading ring references");
1097 return -ENOMEM;
1098 }
1099 snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend,
1100 queue->id);
1101 }
1102
1103 err = xenbus_gather(XBT_NIL, xspath,
1104 "tx-ring-ref", "%lu", &tx_ring_ref,
1105 "rx-ring-ref", "%lu", &rx_ring_ref, NULL);
1106 if (err) {
1107 xenbus_dev_fatal(dev, err,
1108 "reading %s/ring-ref",
1109 xspath);
1110 goto err;
1111 }
1112
1113 /* Try split event channels first, then single event channel. */
1114 err = xenbus_gather(XBT_NIL, xspath,
1115 "event-channel-tx", "%u", &tx_evtchn,
1116 "event-channel-rx", "%u", &rx_evtchn, NULL);
1117 if (err < 0) {
1118 err = xenbus_scanf(XBT_NIL, xspath,
1119 "event-channel", "%u", &tx_evtchn);
1120 if (err < 0) {
1121 xenbus_dev_fatal(dev, err,
1122 "reading %s/event-channel(-tx/rx)",
1123 xspath);
1124 goto err;
1125 }
1126 rx_evtchn = tx_evtchn;
1127 }
1128
1129 /* Map the shared frame, irq etc. */
1130 err = xenvif_connect_data(queue, tx_ring_ref, rx_ring_ref,
1131 tx_evtchn, rx_evtchn);
1132 if (err) {
1133 xenbus_dev_fatal(dev, err,
1134 "mapping shared-frames %lu/%lu port tx %u rx %u",
1135 tx_ring_ref, rx_ring_ref,
1136 tx_evtchn, rx_evtchn);
1137 goto err;
1138 }
1139
1140 err = 0;
1141err: /* Regular return falls through with err == 0 */
1142 kfree(xspath);
1143 return err;
1144}
1145
1146static int read_xenbus_vif_flags(struct backend_info *be)
1147{
1148 struct xenvif *vif = be->vif;
1149 struct xenbus_device *dev = be->dev;
1150 unsigned int rx_copy;
1151 int err;
1152
1153 err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
1154 &rx_copy);
1155 if (err == -ENOENT) {
1156 err = 0;
1157 rx_copy = 0;
1158 }
1159 if (err < 0) {
1160 xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy",
1161 dev->otherend);
1162 return err;
1163 }
1164 if (!rx_copy)
1165 return -EOPNOTSUPP;
1166
1167 if (!xenbus_read_unsigned(dev->otherend, "feature-rx-notify", 0)) {
1168 /* - Reduce drain timeout to poll more frequently for
1169 * Rx requests.
1170 * - Disable Rx stall detection.
1171 */
1172 be->vif->drain_timeout = msecs_to_jiffies(30);
1173 be->vif->stall_timeout = 0;
1174 }
1175
1176 vif->can_sg = !!xenbus_read_unsigned(dev->otherend, "feature-sg", 0);
1177
1178 vif->gso_mask = 0;
1179
1180 if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv4", 0))
1181 vif->gso_mask |= GSO_BIT(TCPV4);
1182
1183 if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv6", 0))
1184 vif->gso_mask |= GSO_BIT(TCPV6);
1185
1186 vif->ip_csum = !xenbus_read_unsigned(dev->otherend,
1187 "feature-no-csum-offload", 0);
1188
1189 vif->ipv6_csum = !!xenbus_read_unsigned(dev->otherend,
1190 "feature-ipv6-csum-offload", 0);
1191
1192 return 0;
1193}
1194
1195static const struct xenbus_device_id netback_ids[] = {
1196 { "vif" },
1197 { "" }
1198};
1199
1200static struct xenbus_driver netback_driver = {
1201 .ids = netback_ids,
1202 .probe = netback_probe,
1203 .remove = netback_remove,
1204 .uevent = netback_uevent,
1205 .otherend_changed = frontend_changed,
1206};
1207
1208int xenvif_xenbus_init(void)
1209{
1210 return xenbus_register_backend(&netback_driver);
1211}
1212
1213void xenvif_xenbus_fini(void)
1214{
1215 return xenbus_unregister_driver(&netback_driver);
1216}
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
198/*
199 * Handle the creation of the hotplug script environment. We add the script
200 * and vif variables to the environment, for the benefit of the vif-* hotplug
201 * scripts.
202 */
203static int netback_uevent(struct xenbus_device *xdev,
204 struct kobj_uevent_env *env)
205{
206 struct backend_info *be = dev_get_drvdata(&xdev->dev);
207
208 if (!be)
209 return 0;
210
211 if (add_uevent_var(env, "script=%s", be->hotplug_script))
212 return -ENOMEM;
213
214 if (!be->vif)
215 return 0;
216
217 return add_uevent_var(env, "vif=%s", be->vif->dev->name);
218}
219
220
221static int backend_create_xenvif(struct backend_info *be)
222{
223 int err;
224 long handle;
225 struct xenbus_device *dev = be->dev;
226 struct xenvif *vif;
227
228 if (be->vif != NULL)
229 return 0;
230
231 err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle);
232 if (err != 1) {
233 xenbus_dev_fatal(dev, err, "reading handle");
234 return (err < 0) ? err : -EINVAL;
235 }
236
237 vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle);
238 if (IS_ERR(vif)) {
239 err = PTR_ERR(vif);
240 xenbus_dev_fatal(dev, err, "creating interface");
241 return err;
242 }
243 be->vif = vif;
244 vif->be = be;
245
246 kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE);
247 return 0;
248}
249
250static void backend_disconnect(struct backend_info *be)
251{
252 struct xenvif *vif = be->vif;
253
254 if (vif) {
255 unsigned int num_queues = vif->num_queues;
256 unsigned int queue_index;
257
258 xen_unregister_watchers(vif);
259#ifdef CONFIG_DEBUG_FS
260 xenvif_debugfs_delif(vif);
261#endif /* CONFIG_DEBUG_FS */
262 xenvif_disconnect_data(vif);
263
264 /* At this point some of the handlers may still be active
265 * so we need to have additional synchronization here.
266 */
267 vif->num_queues = 0;
268 synchronize_net();
269
270 for (queue_index = 0; queue_index < num_queues; ++queue_index)
271 xenvif_deinit_queue(&vif->queues[queue_index]);
272
273 vfree(vif->queues);
274 vif->queues = NULL;
275
276 xenvif_disconnect_ctrl(vif);
277 }
278}
279
280static void backend_connect(struct backend_info *be)
281{
282 if (be->vif)
283 connect(be);
284}
285
286static inline void backend_switch_state(struct backend_info *be,
287 enum xenbus_state state)
288{
289 struct xenbus_device *dev = be->dev;
290
291 pr_debug("%s -> %s\n", dev->nodename, xenbus_strstate(state));
292 be->state = state;
293
294 /* If we are waiting for a hotplug script then defer the
295 * actual xenbus state change.
296 */
297 if (!be->have_hotplug_status_watch)
298 xenbus_switch_state(dev, state);
299}
300
301/* Handle backend state transitions:
302 *
303 * The backend state starts in Initialising and the following transitions are
304 * allowed.
305 *
306 * Initialising -> InitWait -> Connected
307 * \
308 * \ ^ \ |
309 * \ | \ |
310 * \ | \ |
311 * \ | \ |
312 * \ | \ |
313 * \ | \ |
314 * V | V V
315 *
316 * Closed <-> Closing
317 *
318 * The state argument specifies the eventual state of the backend and the
319 * function transitions to that state via the shortest path.
320 */
321static void set_backend_state(struct backend_info *be,
322 enum xenbus_state state)
323{
324 while (be->state != state) {
325 switch (be->state) {
326 case XenbusStateInitialising:
327 switch (state) {
328 case XenbusStateInitWait:
329 case XenbusStateConnected:
330 case XenbusStateClosing:
331 backend_switch_state(be, XenbusStateInitWait);
332 break;
333 case XenbusStateClosed:
334 backend_switch_state(be, XenbusStateClosed);
335 break;
336 default:
337 BUG();
338 }
339 break;
340 case XenbusStateClosed:
341 switch (state) {
342 case XenbusStateInitWait:
343 case XenbusStateConnected:
344 backend_switch_state(be, XenbusStateInitWait);
345 break;
346 case XenbusStateClosing:
347 backend_switch_state(be, XenbusStateClosing);
348 break;
349 default:
350 BUG();
351 }
352 break;
353 case XenbusStateInitWait:
354 switch (state) {
355 case XenbusStateConnected:
356 backend_connect(be);
357 backend_switch_state(be, XenbusStateConnected);
358 break;
359 case XenbusStateClosing:
360 case XenbusStateClosed:
361 backend_switch_state(be, XenbusStateClosing);
362 break;
363 default:
364 BUG();
365 }
366 break;
367 case XenbusStateConnected:
368 switch (state) {
369 case XenbusStateInitWait:
370 case XenbusStateClosing:
371 case XenbusStateClosed:
372 backend_disconnect(be);
373 backend_switch_state(be, XenbusStateClosing);
374 break;
375 default:
376 BUG();
377 }
378 break;
379 case XenbusStateClosing:
380 switch (state) {
381 case XenbusStateInitWait:
382 case XenbusStateConnected:
383 case XenbusStateClosed:
384 backend_switch_state(be, XenbusStateClosed);
385 break;
386 default:
387 BUG();
388 }
389 break;
390 default:
391 BUG();
392 }
393 }
394}
395
396static void read_xenbus_frontend_xdp(struct backend_info *be,
397 struct xenbus_device *dev)
398{
399 struct xenvif *vif = be->vif;
400 u16 headroom;
401 int err;
402
403 err = xenbus_scanf(XBT_NIL, dev->otherend,
404 "xdp-headroom", "%hu", &headroom);
405 if (err != 1) {
406 vif->xdp_headroom = 0;
407 return;
408 }
409 if (headroom > XEN_NETIF_MAX_XDP_HEADROOM)
410 headroom = XEN_NETIF_MAX_XDP_HEADROOM;
411 vif->xdp_headroom = headroom;
412}
413
414/**
415 * Callback received when the frontend's state changes.
416 */
417static void frontend_changed(struct xenbus_device *dev,
418 enum xenbus_state frontend_state)
419{
420 struct backend_info *be = dev_get_drvdata(&dev->dev);
421
422 pr_debug("%s -> %s\n", dev->otherend, xenbus_strstate(frontend_state));
423
424 be->frontend_state = frontend_state;
425
426 switch (frontend_state) {
427 case XenbusStateInitialising:
428 set_backend_state(be, XenbusStateInitWait);
429 break;
430
431 case XenbusStateInitialised:
432 break;
433
434 case XenbusStateConnected:
435 set_backend_state(be, XenbusStateConnected);
436 break;
437
438 case XenbusStateReconfiguring:
439 read_xenbus_frontend_xdp(be, dev);
440 xenbus_switch_state(dev, XenbusStateReconfigured);
441 break;
442
443 case XenbusStateClosing:
444 set_backend_state(be, XenbusStateClosing);
445 break;
446
447 case XenbusStateClosed:
448 set_backend_state(be, XenbusStateClosed);
449 if (xenbus_dev_is_online(dev))
450 break;
451 fallthrough; /* if not online */
452 case XenbusStateUnknown:
453 set_backend_state(be, XenbusStateClosed);
454 device_unregister(&dev->dev);
455 break;
456
457 default:
458 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
459 frontend_state);
460 break;
461 }
462}
463
464
465static void xen_net_read_rate(struct xenbus_device *dev,
466 unsigned long *bytes, unsigned long *usec)
467{
468 char *s, *e;
469 unsigned long b, u;
470 char *ratestr;
471
472 /* Default to unlimited bandwidth. */
473 *bytes = ~0UL;
474 *usec = 0;
475
476 ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL);
477 if (IS_ERR(ratestr))
478 return;
479
480 s = ratestr;
481 b = simple_strtoul(s, &e, 10);
482 if ((s == e) || (*e != ','))
483 goto fail;
484
485 s = e + 1;
486 u = simple_strtoul(s, &e, 10);
487 if ((s == e) || (*e != '\0'))
488 goto fail;
489
490 *bytes = b;
491 *usec = u;
492
493 kfree(ratestr);
494 return;
495
496 fail:
497 pr_warn("Failed to parse network rate limit. Traffic unlimited.\n");
498 kfree(ratestr);
499}
500
501static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
502{
503 char *s, *e, *macstr;
504 int i;
505
506 macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
507 if (IS_ERR(macstr))
508 return PTR_ERR(macstr);
509
510 for (i = 0; i < ETH_ALEN; i++) {
511 mac[i] = simple_strtoul(s, &e, 16);
512 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
513 kfree(macstr);
514 return -ENOENT;
515 }
516 s = e+1;
517 }
518
519 kfree(macstr);
520 return 0;
521}
522
523static void xen_net_rate_changed(struct xenbus_watch *watch,
524 const char *path, const char *token)
525{
526 struct xenvif *vif = container_of(watch, struct xenvif, credit_watch);
527 struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
528 unsigned long credit_bytes;
529 unsigned long credit_usec;
530 unsigned int queue_index;
531
532 xen_net_read_rate(dev, &credit_bytes, &credit_usec);
533 for (queue_index = 0; queue_index < vif->num_queues; queue_index++) {
534 struct xenvif_queue *queue = &vif->queues[queue_index];
535
536 queue->credit_bytes = credit_bytes;
537 queue->credit_usec = credit_usec;
538 if (!mod_timer_pending(&queue->credit_timeout, jiffies) &&
539 queue->remaining_credit > queue->credit_bytes) {
540 queue->remaining_credit = queue->credit_bytes;
541 }
542 }
543}
544
545static int xen_register_credit_watch(struct xenbus_device *dev,
546 struct xenvif *vif)
547{
548 int err = 0;
549 char *node;
550 unsigned maxlen = strlen(dev->nodename) + sizeof("/rate");
551
552 if (vif->credit_watch.node)
553 return -EADDRINUSE;
554
555 node = kmalloc(maxlen, GFP_KERNEL);
556 if (!node)
557 return -ENOMEM;
558 snprintf(node, maxlen, "%s/rate", dev->nodename);
559 vif->credit_watch.node = node;
560 vif->credit_watch.callback = xen_net_rate_changed;
561 err = register_xenbus_watch(&vif->credit_watch);
562 if (err) {
563 pr_err("Failed to set watcher %s\n", vif->credit_watch.node);
564 kfree(node);
565 vif->credit_watch.node = NULL;
566 vif->credit_watch.callback = NULL;
567 }
568 return err;
569}
570
571static void xen_unregister_credit_watch(struct xenvif *vif)
572{
573 if (vif->credit_watch.node) {
574 unregister_xenbus_watch(&vif->credit_watch);
575 kfree(vif->credit_watch.node);
576 vif->credit_watch.node = NULL;
577 }
578}
579
580static void xen_mcast_ctrl_changed(struct xenbus_watch *watch,
581 const char *path, const char *token)
582{
583 struct xenvif *vif = container_of(watch, struct xenvif,
584 mcast_ctrl_watch);
585 struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
586
587 vif->multicast_control = !!xenbus_read_unsigned(dev->otherend,
588 "request-multicast-control", 0);
589}
590
591static int xen_register_mcast_ctrl_watch(struct xenbus_device *dev,
592 struct xenvif *vif)
593{
594 int err = 0;
595 char *node;
596 unsigned maxlen = strlen(dev->otherend) +
597 sizeof("/request-multicast-control");
598
599 if (vif->mcast_ctrl_watch.node) {
600 pr_err_ratelimited("Watch is already registered\n");
601 return -EADDRINUSE;
602 }
603
604 node = kmalloc(maxlen, GFP_KERNEL);
605 if (!node) {
606 pr_err("Failed to allocate memory for watch\n");
607 return -ENOMEM;
608 }
609 snprintf(node, maxlen, "%s/request-multicast-control",
610 dev->otherend);
611 vif->mcast_ctrl_watch.node = node;
612 vif->mcast_ctrl_watch.callback = xen_mcast_ctrl_changed;
613 err = register_xenbus_watch(&vif->mcast_ctrl_watch);
614 if (err) {
615 pr_err("Failed to set watcher %s\n",
616 vif->mcast_ctrl_watch.node);
617 kfree(node);
618 vif->mcast_ctrl_watch.node = NULL;
619 vif->mcast_ctrl_watch.callback = NULL;
620 }
621 return err;
622}
623
624static void xen_unregister_mcast_ctrl_watch(struct xenvif *vif)
625{
626 if (vif->mcast_ctrl_watch.node) {
627 unregister_xenbus_watch(&vif->mcast_ctrl_watch);
628 kfree(vif->mcast_ctrl_watch.node);
629 vif->mcast_ctrl_watch.node = NULL;
630 }
631}
632
633static void xen_register_watchers(struct xenbus_device *dev,
634 struct xenvif *vif)
635{
636 xen_register_credit_watch(dev, vif);
637 xen_register_mcast_ctrl_watch(dev, vif);
638}
639
640static void xen_unregister_watchers(struct xenvif *vif)
641{
642 xen_unregister_mcast_ctrl_watch(vif);
643 xen_unregister_credit_watch(vif);
644}
645
646static void unregister_hotplug_status_watch(struct backend_info *be)
647{
648 if (be->have_hotplug_status_watch) {
649 unregister_xenbus_watch(&be->hotplug_status_watch);
650 kfree(be->hotplug_status_watch.node);
651 }
652 be->have_hotplug_status_watch = 0;
653}
654
655static void hotplug_status_changed(struct xenbus_watch *watch,
656 const char *path,
657 const char *token)
658{
659 struct backend_info *be = container_of(watch,
660 struct backend_info,
661 hotplug_status_watch);
662 char *str;
663 unsigned int len;
664
665 str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len);
666 if (IS_ERR(str))
667 return;
668 if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) {
669 /* Complete any pending state change */
670 xenbus_switch_state(be->dev, be->state);
671
672 /* Not interested in this watch anymore. */
673 unregister_hotplug_status_watch(be);
674 xenbus_rm(XBT_NIL, be->dev->nodename, "hotplug-status");
675 }
676 kfree(str);
677}
678
679static int connect_ctrl_ring(struct backend_info *be)
680{
681 struct xenbus_device *dev = be->dev;
682 struct xenvif *vif = be->vif;
683 unsigned int val;
684 grant_ref_t ring_ref;
685 unsigned int evtchn;
686 int err;
687
688 err = xenbus_scanf(XBT_NIL, dev->otherend,
689 "ctrl-ring-ref", "%u", &val);
690 if (err < 0)
691 goto done; /* The frontend does not have a control ring */
692
693 ring_ref = val;
694
695 err = xenbus_scanf(XBT_NIL, dev->otherend,
696 "event-channel-ctrl", "%u", &val);
697 if (err < 0) {
698 xenbus_dev_fatal(dev, err,
699 "reading %s/event-channel-ctrl",
700 dev->otherend);
701 goto fail;
702 }
703
704 evtchn = val;
705
706 err = xenvif_connect_ctrl(vif, ring_ref, evtchn);
707 if (err) {
708 xenbus_dev_fatal(dev, err,
709 "mapping shared-frame %u port %u",
710 ring_ref, evtchn);
711 goto fail;
712 }
713
714done:
715 return 0;
716
717fail:
718 return err;
719}
720
721static void connect(struct backend_info *be)
722{
723 int err;
724 struct xenbus_device *dev = be->dev;
725 unsigned long credit_bytes, credit_usec;
726 unsigned int queue_index;
727 unsigned int requested_num_queues;
728 struct xenvif_queue *queue;
729
730 /* Check whether the frontend requested multiple queues
731 * and read the number requested.
732 */
733 requested_num_queues = xenbus_read_unsigned(dev->otherend,
734 "multi-queue-num-queues", 1);
735 if (requested_num_queues > xenvif_max_queues) {
736 /* buggy or malicious guest */
737 xenbus_dev_fatal(dev, -EINVAL,
738 "guest requested %u queues, exceeding the maximum of %u.",
739 requested_num_queues, xenvif_max_queues);
740 return;
741 }
742
743 err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
744 if (err) {
745 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
746 return;
747 }
748
749 xen_net_read_rate(dev, &credit_bytes, &credit_usec);
750 xen_unregister_watchers(be->vif);
751 xen_register_watchers(dev, be->vif);
752 read_xenbus_vif_flags(be);
753
754 err = connect_ctrl_ring(be);
755 if (err) {
756 xenbus_dev_fatal(dev, err, "connecting control ring");
757 return;
758 }
759
760 /* Use the number of queues requested by the frontend */
761 be->vif->queues = vzalloc(array_size(requested_num_queues,
762 sizeof(struct xenvif_queue)));
763 if (!be->vif->queues) {
764 xenbus_dev_fatal(dev, -ENOMEM,
765 "allocating queues");
766 return;
767 }
768
769 be->vif->num_queues = requested_num_queues;
770 be->vif->stalled_queues = requested_num_queues;
771
772 for (queue_index = 0; queue_index < requested_num_queues; ++queue_index) {
773 queue = &be->vif->queues[queue_index];
774 queue->vif = be->vif;
775 queue->id = queue_index;
776 snprintf(queue->name, sizeof(queue->name), "%s-q%u",
777 be->vif->dev->name, queue->id);
778
779 err = xenvif_init_queue(queue);
780 if (err) {
781 /* xenvif_init_queue() cleans up after itself on
782 * failure, but we need to clean up any previously
783 * initialised queues. Set num_queues to i so that
784 * earlier queues can be destroyed using the regular
785 * disconnect logic.
786 */
787 be->vif->num_queues = queue_index;
788 goto err;
789 }
790
791 queue->credit_bytes = credit_bytes;
792 queue->remaining_credit = credit_bytes;
793 queue->credit_usec = credit_usec;
794
795 err = connect_data_rings(be, queue);
796 if (err) {
797 /* connect_data_rings() cleans up after itself on
798 * failure, but we need to clean up after
799 * xenvif_init_queue() here, and also clean up any
800 * previously initialised queues.
801 */
802 xenvif_deinit_queue(queue);
803 be->vif->num_queues = queue_index;
804 goto err;
805 }
806 }
807
808#ifdef CONFIG_DEBUG_FS
809 xenvif_debugfs_addif(be->vif);
810#endif /* CONFIG_DEBUG_FS */
811
812 /* Initialisation completed, tell core driver the number of
813 * active queues.
814 */
815 rtnl_lock();
816 netif_set_real_num_tx_queues(be->vif->dev, requested_num_queues);
817 netif_set_real_num_rx_queues(be->vif->dev, requested_num_queues);
818 rtnl_unlock();
819
820 xenvif_carrier_on(be->vif);
821
822 unregister_hotplug_status_watch(be);
823 err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
824 hotplug_status_changed,
825 "%s/%s", dev->nodename, "hotplug-status");
826 if (!err)
827 be->have_hotplug_status_watch = 1;
828
829 netif_tx_wake_all_queues(be->vif->dev);
830
831 return;
832
833err:
834 if (be->vif->num_queues > 0)
835 xenvif_disconnect_data(be->vif); /* Clean up existing queues */
836 for (queue_index = 0; queue_index < be->vif->num_queues; ++queue_index)
837 xenvif_deinit_queue(&be->vif->queues[queue_index]);
838 vfree(be->vif->queues);
839 be->vif->queues = NULL;
840 be->vif->num_queues = 0;
841 xenvif_disconnect_ctrl(be->vif);
842 return;
843}
844
845
846static int connect_data_rings(struct backend_info *be,
847 struct xenvif_queue *queue)
848{
849 struct xenbus_device *dev = be->dev;
850 unsigned int num_queues = queue->vif->num_queues;
851 unsigned long tx_ring_ref, rx_ring_ref;
852 unsigned int tx_evtchn, rx_evtchn;
853 int err;
854 char *xspath;
855 size_t xspathsize;
856 const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */
857
858 /* If the frontend requested 1 queue, or we have fallen back
859 * to single queue due to lack of frontend support for multi-
860 * queue, expect the remaining XenStore keys in the toplevel
861 * directory. Otherwise, expect them in a subdirectory called
862 * queue-N.
863 */
864 if (num_queues == 1) {
865 xspath = kzalloc(strlen(dev->otherend) + 1, GFP_KERNEL);
866 if (!xspath) {
867 xenbus_dev_fatal(dev, -ENOMEM,
868 "reading ring references");
869 return -ENOMEM;
870 }
871 strcpy(xspath, dev->otherend);
872 } else {
873 xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
874 xspath = kzalloc(xspathsize, GFP_KERNEL);
875 if (!xspath) {
876 xenbus_dev_fatal(dev, -ENOMEM,
877 "reading ring references");
878 return -ENOMEM;
879 }
880 snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend,
881 queue->id);
882 }
883
884 err = xenbus_gather(XBT_NIL, xspath,
885 "tx-ring-ref", "%lu", &tx_ring_ref,
886 "rx-ring-ref", "%lu", &rx_ring_ref, NULL);
887 if (err) {
888 xenbus_dev_fatal(dev, err,
889 "reading %s/ring-ref",
890 xspath);
891 goto err;
892 }
893
894 /* Try split event channels first, then single event channel. */
895 err = xenbus_gather(XBT_NIL, xspath,
896 "event-channel-tx", "%u", &tx_evtchn,
897 "event-channel-rx", "%u", &rx_evtchn, NULL);
898 if (err < 0) {
899 err = xenbus_scanf(XBT_NIL, xspath,
900 "event-channel", "%u", &tx_evtchn);
901 if (err < 0) {
902 xenbus_dev_fatal(dev, err,
903 "reading %s/event-channel(-tx/rx)",
904 xspath);
905 goto err;
906 }
907 rx_evtchn = tx_evtchn;
908 }
909
910 /* Map the shared frame, irq etc. */
911 err = xenvif_connect_data(queue, tx_ring_ref, rx_ring_ref,
912 tx_evtchn, rx_evtchn);
913 if (err) {
914 xenbus_dev_fatal(dev, err,
915 "mapping shared-frames %lu/%lu port tx %u rx %u",
916 tx_ring_ref, rx_ring_ref,
917 tx_evtchn, rx_evtchn);
918 goto err;
919 }
920
921 err = 0;
922err: /* Regular return falls through with err == 0 */
923 kfree(xspath);
924 return err;
925}
926
927static int read_xenbus_vif_flags(struct backend_info *be)
928{
929 struct xenvif *vif = be->vif;
930 struct xenbus_device *dev = be->dev;
931 unsigned int rx_copy;
932 int err;
933
934 err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
935 &rx_copy);
936 if (err == -ENOENT) {
937 err = 0;
938 rx_copy = 0;
939 }
940 if (err < 0) {
941 xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy",
942 dev->otherend);
943 return err;
944 }
945 if (!rx_copy)
946 return -EOPNOTSUPP;
947
948 if (!xenbus_read_unsigned(dev->otherend, "feature-rx-notify", 0)) {
949 /* - Reduce drain timeout to poll more frequently for
950 * Rx requests.
951 * - Disable Rx stall detection.
952 */
953 be->vif->drain_timeout = msecs_to_jiffies(30);
954 be->vif->stall_timeout = 0;
955 }
956
957 vif->can_sg = !!xenbus_read_unsigned(dev->otherend, "feature-sg", 0);
958
959 vif->gso_mask = 0;
960
961 if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv4", 0))
962 vif->gso_mask |= GSO_BIT(TCPV4);
963
964 if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv6", 0))
965 vif->gso_mask |= GSO_BIT(TCPV6);
966
967 vif->ip_csum = !xenbus_read_unsigned(dev->otherend,
968 "feature-no-csum-offload", 0);
969
970 vif->ipv6_csum = !!xenbus_read_unsigned(dev->otherend,
971 "feature-ipv6-csum-offload", 0);
972
973 read_xenbus_frontend_xdp(be, dev);
974
975 return 0;
976}
977
978static int netback_remove(struct xenbus_device *dev)
979{
980 struct backend_info *be = dev_get_drvdata(&dev->dev);
981
982 unregister_hotplug_status_watch(be);
983 if (be->vif) {
984 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
985 backend_disconnect(be);
986 xenvif_free(be->vif);
987 be->vif = NULL;
988 }
989 kfree(be->hotplug_script);
990 kfree(be);
991 dev_set_drvdata(&dev->dev, NULL);
992 return 0;
993}
994
995/**
996 * Entry point to this code when a new device is created. Allocate the basic
997 * structures and switch to InitWait.
998 */
999static int netback_probe(struct xenbus_device *dev,
1000 const struct xenbus_device_id *id)
1001{
1002 const char *message;
1003 struct xenbus_transaction xbt;
1004 int err;
1005 int sg;
1006 const char *script;
1007 struct backend_info *be = kzalloc(sizeof(*be), GFP_KERNEL);
1008
1009 if (!be) {
1010 xenbus_dev_fatal(dev, -ENOMEM,
1011 "allocating backend structure");
1012 return -ENOMEM;
1013 }
1014
1015 be->dev = dev;
1016 dev_set_drvdata(&dev->dev, be);
1017
1018 sg = 1;
1019
1020 do {
1021 err = xenbus_transaction_start(&xbt);
1022 if (err) {
1023 xenbus_dev_fatal(dev, err, "starting transaction");
1024 goto fail;
1025 }
1026
1027 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", sg);
1028 if (err) {
1029 message = "writing feature-sg";
1030 goto abort_transaction;
1031 }
1032
1033 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4",
1034 "%d", sg);
1035 if (err) {
1036 message = "writing feature-gso-tcpv4";
1037 goto abort_transaction;
1038 }
1039
1040 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv6",
1041 "%d", sg);
1042 if (err) {
1043 message = "writing feature-gso-tcpv6";
1044 goto abort_transaction;
1045 }
1046
1047 /* We support partial checksum setup for IPv6 packets */
1048 err = xenbus_printf(xbt, dev->nodename,
1049 "feature-ipv6-csum-offload",
1050 "%d", 1);
1051 if (err) {
1052 message = "writing feature-ipv6-csum-offload";
1053 goto abort_transaction;
1054 }
1055
1056 /* We support rx-copy path. */
1057 err = xenbus_printf(xbt, dev->nodename,
1058 "feature-rx-copy", "%d", 1);
1059 if (err) {
1060 message = "writing feature-rx-copy";
1061 goto abort_transaction;
1062 }
1063
1064 /* we can adjust a headroom for netfront XDP processing */
1065 err = xenbus_printf(xbt, dev->nodename,
1066 "feature-xdp-headroom", "%d",
1067 provides_xdp_headroom);
1068 if (err) {
1069 message = "writing feature-xdp-headroom";
1070 goto abort_transaction;
1071 }
1072
1073 /* We don't support rx-flip path (except old guests who
1074 * don't grok this feature flag).
1075 */
1076 err = xenbus_printf(xbt, dev->nodename,
1077 "feature-rx-flip", "%d", 0);
1078 if (err) {
1079 message = "writing feature-rx-flip";
1080 goto abort_transaction;
1081 }
1082
1083 /* We support dynamic multicast-control. */
1084 err = xenbus_printf(xbt, dev->nodename,
1085 "feature-multicast-control", "%d", 1);
1086 if (err) {
1087 message = "writing feature-multicast-control";
1088 goto abort_transaction;
1089 }
1090
1091 err = xenbus_printf(xbt, dev->nodename,
1092 "feature-dynamic-multicast-control",
1093 "%d", 1);
1094 if (err) {
1095 message = "writing feature-dynamic-multicast-control";
1096 goto abort_transaction;
1097 }
1098
1099 err = xenbus_transaction_end(xbt, 0);
1100 } while (err == -EAGAIN);
1101
1102 if (err) {
1103 xenbus_dev_fatal(dev, err, "completing transaction");
1104 goto fail;
1105 }
1106
1107 /* Split event channels support, this is optional so it is not
1108 * put inside the above loop.
1109 */
1110 err = xenbus_printf(XBT_NIL, dev->nodename,
1111 "feature-split-event-channels",
1112 "%u", separate_tx_rx_irq);
1113 if (err)
1114 pr_debug("Error writing feature-split-event-channels\n");
1115
1116 /* Multi-queue support: This is an optional feature. */
1117 err = xenbus_printf(XBT_NIL, dev->nodename,
1118 "multi-queue-max-queues", "%u", xenvif_max_queues);
1119 if (err)
1120 pr_debug("Error writing multi-queue-max-queues\n");
1121
1122 err = xenbus_printf(XBT_NIL, dev->nodename,
1123 "feature-ctrl-ring",
1124 "%u", true);
1125 if (err)
1126 pr_debug("Error writing feature-ctrl-ring\n");
1127
1128 backend_switch_state(be, XenbusStateInitWait);
1129
1130 script = xenbus_read(XBT_NIL, dev->nodename, "script", NULL);
1131 if (IS_ERR(script)) {
1132 err = PTR_ERR(script);
1133 xenbus_dev_fatal(dev, err, "reading script");
1134 goto fail;
1135 }
1136
1137 be->hotplug_script = script;
1138
1139 /* This kicks hotplug scripts, so do it immediately. */
1140 err = backend_create_xenvif(be);
1141 if (err)
1142 goto fail;
1143
1144 return 0;
1145
1146abort_transaction:
1147 xenbus_transaction_end(xbt, 1);
1148 xenbus_dev_fatal(dev, err, "%s", message);
1149fail:
1150 pr_debug("failed\n");
1151 netback_remove(dev);
1152 return err;
1153}
1154
1155static const struct xenbus_device_id netback_ids[] = {
1156 { "vif" },
1157 { "" }
1158};
1159
1160static struct xenbus_driver netback_driver = {
1161 .ids = netback_ids,
1162 .probe = netback_probe,
1163 .remove = netback_remove,
1164 .uevent = netback_uevent,
1165 .otherend_changed = frontend_changed,
1166 .allow_rebind = true,
1167};
1168
1169int xenvif_xenbus_init(void)
1170{
1171 return xenbus_register_backend(&netback_driver);
1172}
1173
1174void xenvif_xenbus_fini(void)
1175{
1176 return xenbus_unregister_driver(&netback_driver);
1177}