2 * Xenbus code for netif backend
4 * Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au>
5 * Copyright (C) 2005 XenSource Ltd
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.
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.
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/>.
22 #include <linux/vmalloc.h>
23 #include <linux/rtnetlink.h>
26 struct xenbus_device *dev;
29 /* This is the state that will be reflected in xenstore when any
30 * active hotplug script completes.
32 enum xenbus_state state;
34 enum xenbus_state frontend_state;
35 struct xenbus_watch hotplug_status_watch;
36 u8 have_hotplug_status_watch:1;
38 const char *hotplug_script;
41 static int connect_rings(struct backend_info *be, struct xenvif_queue *queue);
42 static void connect(struct backend_info *be);
43 static int read_xenbus_vif_flags(struct backend_info *be);
44 static int backend_create_xenvif(struct backend_info *be);
45 static void unregister_hotplug_status_watch(struct backend_info *be);
46 static void xen_unregister_watchers(struct xenvif *vif);
47 static void set_backend_state(struct backend_info *be,
48 enum xenbus_state state);
50 #ifdef CONFIG_DEBUG_FS
51 struct dentry *xen_netback_dbg_root = NULL;
53 static int xenvif_read_io_ring(struct seq_file *m, void *v)
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;
61 struct xen_netif_tx_sring *sring = tx_ring->sring;
63 seq_printf(m, "Queue %d\nTX: nr_ents %u\n", queue->id,
65 seq_printf(m, "req prod %u (%d) cons %u (%d) event %u (%d)\n",
67 sring->req_prod - sring->rsp_prod,
69 tx_ring->req_cons - sring->rsp_prod,
71 sring->req_event - sring->rsp_prod);
72 seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n",
74 tx_ring->rsp_prod_pvt,
75 tx_ring->rsp_prod_pvt - sring->rsp_prod,
77 sring->rsp_event - sring->rsp_prod);
78 seq_printf(m, "pending prod %u pending cons %u nr_pending_reqs %u\n",
81 nr_pending_reqs(queue));
82 seq_printf(m, "dealloc prod %u dealloc cons %u dealloc_queue %u\n\n",
85 queue->dealloc_prod - queue->dealloc_cons);
89 struct xen_netif_rx_sring *sring = rx_ring->sring;
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",
94 sring->req_prod - sring->rsp_prod,
96 rx_ring->req_cons - sring->rsp_prod,
98 sring->req_event - sring->rsp_prod);
99 seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n\n",
101 rx_ring->rsp_prod_pvt,
102 rx_ring->rsp_prod_pvt - sring->rsp_prod,
104 sring->rsp_event - sring->rsp_prod);
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),
115 queue->remaining_credit,
116 queue->credit_timeout.expires,
119 dev_queue = netdev_get_tx_queue(queue->vif->dev, queue->id);
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");
129 #define XENVIF_KICK_STR "kick"
130 #define BUFFER_SIZE 32
133 xenvif_write_io_ring(struct file *filp, const char __user *buf, size_t count,
136 struct xenvif_queue *queue =
137 ((struct seq_file *)filp->private_data)->private;
139 char write[BUFFER_SIZE];
141 /* don't allow partial writes and check the length */
144 if (count >= sizeof(write))
147 len = simple_write_to_buffer(write,
157 if (!strncmp(write, XENVIF_KICK_STR, sizeof(XENVIF_KICK_STR) - 1))
158 xenvif_interrupt(0, (void *)queue);
160 pr_warn("Unknown command to io_ring_q%d. Available: kick\n",
167 static int xenvif_dump_open(struct inode *inode, struct file *filp)
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;
179 static const struct file_operations xenvif_dbg_io_ring_ops_fops = {
180 .owner = THIS_MODULE,
181 .open = xenvif_dump_open,
184 .release = single_release,
185 .write = xenvif_write_io_ring,
188 static void xenvif_debugfs_addif(struct xenvif *vif)
190 struct dentry *pfile;
193 if (IS_ERR_OR_NULL(xen_netback_dbg_root))
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];
202 snprintf(filename, sizeof(filename), "io_ring_q%d", i);
203 pfile = debugfs_create_file(filename,
205 vif->xenvif_dbg_root,
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",
213 netdev_warn(vif->dev,
214 "Creation of vif debugfs dir returned %ld!\n",
215 PTR_ERR(vif->xenvif_dbg_root));
218 static void xenvif_debugfs_delif(struct xenvif *vif)
220 if (IS_ERR_OR_NULL(xen_netback_dbg_root))
223 if (!IS_ERR_OR_NULL(vif->xenvif_dbg_root))
224 debugfs_remove_recursive(vif->xenvif_dbg_root);
225 vif->xenvif_dbg_root = NULL;
227 #endif /* CONFIG_DEBUG_FS */
229 static int netback_remove(struct xenbus_device *dev)
231 struct backend_info *be = dev_get_drvdata(&dev->dev);
233 set_backend_state(be, XenbusStateClosed);
235 unregister_hotplug_status_watch(be);
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);
243 kfree(be->hotplug_script);
245 dev_set_drvdata(&dev->dev, NULL);
251 * Entry point to this code when a new device is created. Allocate the basic
252 * structures and switch to InitWait.
254 static int netback_probe(struct xenbus_device *dev,
255 const struct xenbus_device_id *id)
258 struct xenbus_transaction xbt;
262 struct backend_info *be = kzalloc(sizeof(struct backend_info),
265 xenbus_dev_fatal(dev, -ENOMEM,
266 "allocating backend structure");
271 dev_set_drvdata(&dev->dev, be);
276 err = xenbus_transaction_start(&xbt);
278 xenbus_dev_fatal(dev, err, "starting transaction");
282 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", sg);
284 message = "writing feature-sg";
285 goto abort_transaction;
288 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4",
291 message = "writing feature-gso-tcpv4";
292 goto abort_transaction;
295 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv6",
298 message = "writing feature-gso-tcpv6";
299 goto abort_transaction;
302 /* We support partial checksum setup for IPv6 packets */
303 err = xenbus_printf(xbt, dev->nodename,
304 "feature-ipv6-csum-offload",
307 message = "writing feature-ipv6-csum-offload";
308 goto abort_transaction;
311 /* We support rx-copy path. */
312 err = xenbus_printf(xbt, dev->nodename,
313 "feature-rx-copy", "%d", 1);
315 message = "writing feature-rx-copy";
316 goto abort_transaction;
320 * We don't support rx-flip path (except old guests who don't
321 * grok this feature flag).
323 err = xenbus_printf(xbt, dev->nodename,
324 "feature-rx-flip", "%d", 0);
326 message = "writing feature-rx-flip";
327 goto abort_transaction;
330 /* We support dynamic multicast-control. */
331 err = xenbus_printf(xbt, dev->nodename,
332 "feature-multicast-control", "%d", 1);
334 message = "writing feature-multicast-control";
335 goto abort_transaction;
338 err = xenbus_printf(xbt, dev->nodename,
339 "feature-dynamic-multicast-control",
342 message = "writing feature-dynamic-multicast-control";
343 goto abort_transaction;
346 err = xenbus_transaction_end(xbt, 0);
347 } while (err == -EAGAIN);
350 xenbus_dev_fatal(dev, err, "completing transaction");
355 * Split event channels support, this is optional so it is not
356 * put inside the above loop.
358 err = xenbus_printf(XBT_NIL, dev->nodename,
359 "feature-split-event-channels",
360 "%u", separate_tx_rx_irq);
362 pr_debug("Error writing feature-split-event-channels\n");
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);
368 pr_debug("Error writing multi-queue-max-queues\n");
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");
377 be->hotplug_script = script;
379 err = xenbus_switch_state(dev, XenbusStateInitWait);
383 be->state = XenbusStateInitWait;
385 /* This kicks hotplug scripts, so do it immediately. */
386 err = backend_create_xenvif(be);
393 xenbus_transaction_end(xbt, 1);
394 xenbus_dev_fatal(dev, err, "%s", message);
396 pr_debug("failed\n");
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
407 static int netback_uevent(struct xenbus_device *xdev,
408 struct kobj_uevent_env *env)
410 struct backend_info *be = dev_get_drvdata(&xdev->dev);
415 if (add_uevent_var(env, "script=%s", be->hotplug_script))
421 return add_uevent_var(env, "vif=%s", be->vif->dev->name);
425 static int backend_create_xenvif(struct backend_info *be)
429 struct xenbus_device *dev = be->dev;
435 err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle);
437 xenbus_dev_fatal(dev, err, "reading handle");
438 return (err < 0) ? err : -EINVAL;
441 vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle);
444 xenbus_dev_fatal(dev, err, "creating interface");
449 kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE);
453 static void backend_disconnect(struct backend_info *be)
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);
464 static void backend_connect(struct backend_info *be)
470 static inline void backend_switch_state(struct backend_info *be,
471 enum xenbus_state state)
473 struct xenbus_device *dev = be->dev;
475 pr_debug("%s -> %s\n", dev->nodename, xenbus_strstate(state));
478 /* If we are waiting for a hotplug script then defer the
479 * actual xenbus state change.
481 if (!be->have_hotplug_status_watch)
482 xenbus_switch_state(dev, state);
485 /* Handle backend state transitions:
487 * The backend state starts in InitWait and the following transitions are
490 * InitWait -> Connected
502 * The state argument specifies the eventual state of the backend and the
503 * function transitions to that state via the shortest path.
505 static void set_backend_state(struct backend_info *be,
506 enum xenbus_state state)
508 while (be->state != state) {
510 case XenbusStateClosed:
512 case XenbusStateInitWait:
513 case XenbusStateConnected:
514 pr_info("%s: prepare for reconnect\n",
516 backend_switch_state(be, XenbusStateInitWait);
518 case XenbusStateClosing:
519 backend_switch_state(be, XenbusStateClosing);
525 case XenbusStateInitWait:
527 case XenbusStateConnected:
529 backend_switch_state(be, XenbusStateConnected);
531 case XenbusStateClosing:
532 case XenbusStateClosed:
533 backend_switch_state(be, XenbusStateClosing);
539 case XenbusStateConnected:
541 case XenbusStateInitWait:
542 case XenbusStateClosing:
543 case XenbusStateClosed:
544 backend_disconnect(be);
545 backend_switch_state(be, XenbusStateClosing);
551 case XenbusStateClosing:
553 case XenbusStateInitWait:
554 case XenbusStateConnected:
555 case XenbusStateClosed:
556 backend_switch_state(be, XenbusStateClosed);
569 * Callback received when the frontend's state changes.
571 static void frontend_changed(struct xenbus_device *dev,
572 enum xenbus_state frontend_state)
574 struct backend_info *be = dev_get_drvdata(&dev->dev);
576 pr_debug("%s -> %s\n", dev->otherend, xenbus_strstate(frontend_state));
578 be->frontend_state = frontend_state;
580 switch (frontend_state) {
581 case XenbusStateInitialising:
582 set_backend_state(be, XenbusStateInitWait);
585 case XenbusStateInitialised:
588 case XenbusStateConnected:
589 set_backend_state(be, XenbusStateConnected);
592 case XenbusStateClosing:
593 set_backend_state(be, XenbusStateClosing);
596 case XenbusStateClosed:
597 set_backend_state(be, XenbusStateClosed);
598 if (xenbus_dev_is_online(dev))
600 /* fall through if not online */
601 case XenbusStateUnknown:
602 set_backend_state(be, XenbusStateClosed);
603 device_unregister(&dev->dev);
607 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
614 static void xen_net_read_rate(struct xenbus_device *dev,
615 unsigned long *bytes, unsigned long *usec)
621 /* Default to unlimited bandwidth. */
625 ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL);
630 b = simple_strtoul(s, &e, 10);
631 if ((s == e) || (*e != ','))
635 u = simple_strtoul(s, &e, 10);
636 if ((s == e) || (*e != '\0'))
646 pr_warn("Failed to parse network rate limit. Traffic unlimited.\n");
650 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
652 char *s, *e, *macstr;
655 macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
657 return PTR_ERR(macstr);
659 for (i = 0; i < ETH_ALEN; i++) {
660 mac[i] = simple_strtoul(s, &e, 16);
661 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
672 static void xen_net_rate_changed(struct xenbus_watch *watch,
673 const char **vec, unsigned int len)
675 struct xenvif *vif = container_of(watch, struct xenvif, credit_watch);
676 struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
677 unsigned long credit_bytes;
678 unsigned long credit_usec;
679 unsigned int queue_index;
681 xen_net_read_rate(dev, &credit_bytes, &credit_usec);
682 for (queue_index = 0; queue_index < vif->num_queues; queue_index++) {
683 struct xenvif_queue *queue = &vif->queues[queue_index];
685 queue->credit_bytes = credit_bytes;
686 queue->credit_usec = credit_usec;
687 if (!mod_timer_pending(&queue->credit_timeout, jiffies) &&
688 queue->remaining_credit > queue->credit_bytes) {
689 queue->remaining_credit = queue->credit_bytes;
694 static int xen_register_credit_watch(struct xenbus_device *dev,
699 unsigned maxlen = strlen(dev->nodename) + sizeof("/rate");
701 if (vif->credit_watch.node)
704 node = kmalloc(maxlen, GFP_KERNEL);
707 snprintf(node, maxlen, "%s/rate", dev->nodename);
708 vif->credit_watch.node = node;
709 vif->credit_watch.callback = xen_net_rate_changed;
710 err = register_xenbus_watch(&vif->credit_watch);
712 pr_err("Failed to set watcher %s\n", vif->credit_watch.node);
714 vif->credit_watch.node = NULL;
715 vif->credit_watch.callback = NULL;
720 static void xen_unregister_credit_watch(struct xenvif *vif)
722 if (vif->credit_watch.node) {
723 unregister_xenbus_watch(&vif->credit_watch);
724 kfree(vif->credit_watch.node);
725 vif->credit_watch.node = NULL;
729 static void xen_mcast_ctrl_changed(struct xenbus_watch *watch,
730 const char **vec, unsigned int len)
732 struct xenvif *vif = container_of(watch, struct xenvif,
734 struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
737 if (xenbus_scanf(XBT_NIL, dev->otherend,
738 "request-multicast-control", "%d", &val) < 0)
740 vif->multicast_control = !!val;
743 static int xen_register_mcast_ctrl_watch(struct xenbus_device *dev,
748 unsigned maxlen = strlen(dev->otherend) +
749 sizeof("/request-multicast-control");
751 if (vif->mcast_ctrl_watch.node) {
752 pr_err_ratelimited("Watch is already registered\n");
756 node = kmalloc(maxlen, GFP_KERNEL);
758 pr_err("Failed to allocate memory for watch\n");
761 snprintf(node, maxlen, "%s/request-multicast-control",
763 vif->mcast_ctrl_watch.node = node;
764 vif->mcast_ctrl_watch.callback = xen_mcast_ctrl_changed;
765 err = register_xenbus_watch(&vif->mcast_ctrl_watch);
767 pr_err("Failed to set watcher %s\n",
768 vif->mcast_ctrl_watch.node);
770 vif->mcast_ctrl_watch.node = NULL;
771 vif->mcast_ctrl_watch.callback = NULL;
776 static void xen_unregister_mcast_ctrl_watch(struct xenvif *vif)
778 if (vif->mcast_ctrl_watch.node) {
779 unregister_xenbus_watch(&vif->mcast_ctrl_watch);
780 kfree(vif->mcast_ctrl_watch.node);
781 vif->mcast_ctrl_watch.node = NULL;
785 static void xen_register_watchers(struct xenbus_device *dev,
788 xen_register_credit_watch(dev, vif);
789 xen_register_mcast_ctrl_watch(dev, vif);
792 static void xen_unregister_watchers(struct xenvif *vif)
794 xen_unregister_mcast_ctrl_watch(vif);
795 xen_unregister_credit_watch(vif);
798 static void unregister_hotplug_status_watch(struct backend_info *be)
800 if (be->have_hotplug_status_watch) {
801 unregister_xenbus_watch(&be->hotplug_status_watch);
802 kfree(be->hotplug_status_watch.node);
804 be->have_hotplug_status_watch = 0;
807 static void hotplug_status_changed(struct xenbus_watch *watch,
809 unsigned int vec_size)
811 struct backend_info *be = container_of(watch,
813 hotplug_status_watch);
817 str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len);
820 if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) {
821 /* Complete any pending state change */
822 xenbus_switch_state(be->dev, be->state);
824 /* Not interested in this watch anymore. */
825 unregister_hotplug_status_watch(be);
830 static void connect(struct backend_info *be)
833 struct xenbus_device *dev = be->dev;
834 unsigned long credit_bytes, credit_usec;
835 unsigned int queue_index;
836 unsigned int requested_num_queues;
837 struct xenvif_queue *queue;
839 /* Check whether the frontend requested multiple queues
840 * and read the number requested.
842 err = xenbus_scanf(XBT_NIL, dev->otherend,
843 "multi-queue-num-queues",
844 "%u", &requested_num_queues);
846 requested_num_queues = 1; /* Fall back to single queue */
847 } else if (requested_num_queues > xenvif_max_queues) {
848 /* buggy or malicious guest */
849 xenbus_dev_fatal(dev, err,
850 "guest requested %u queues, exceeding the maximum of %u.",
851 requested_num_queues, xenvif_max_queues);
855 err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
857 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
861 xen_net_read_rate(dev, &credit_bytes, &credit_usec);
862 xen_unregister_watchers(be->vif);
863 xen_register_watchers(dev, be->vif);
864 read_xenbus_vif_flags(be);
866 /* Use the number of queues requested by the frontend */
867 be->vif->queues = vzalloc(requested_num_queues *
868 sizeof(struct xenvif_queue));
869 if (!be->vif->queues) {
870 xenbus_dev_fatal(dev, -ENOMEM,
871 "allocating queues");
875 be->vif->num_queues = requested_num_queues;
876 be->vif->stalled_queues = requested_num_queues;
878 for (queue_index = 0; queue_index < requested_num_queues; ++queue_index) {
879 queue = &be->vif->queues[queue_index];
880 queue->vif = be->vif;
881 queue->id = queue_index;
882 snprintf(queue->name, sizeof(queue->name), "%s-q%u",
883 be->vif->dev->name, queue->id);
885 err = xenvif_init_queue(queue);
887 /* xenvif_init_queue() cleans up after itself on
888 * failure, but we need to clean up any previously
889 * initialised queues. Set num_queues to i so that
890 * earlier queues can be destroyed using the regular
893 be->vif->num_queues = queue_index;
897 queue->credit_bytes = credit_bytes;
898 queue->remaining_credit = credit_bytes;
899 queue->credit_usec = credit_usec;
901 err = connect_rings(be, queue);
903 /* connect_rings() cleans up after itself on failure,
904 * but we need to clean up after xenvif_init_queue() here,
905 * and also clean up any previously initialised queues.
907 xenvif_deinit_queue(queue);
908 be->vif->num_queues = queue_index;
913 #ifdef CONFIG_DEBUG_FS
914 xenvif_debugfs_addif(be->vif);
915 #endif /* CONFIG_DEBUG_FS */
917 /* Initialisation completed, tell core driver the number of
921 netif_set_real_num_tx_queues(be->vif->dev, requested_num_queues);
922 netif_set_real_num_rx_queues(be->vif->dev, requested_num_queues);
925 xenvif_carrier_on(be->vif);
927 unregister_hotplug_status_watch(be);
928 err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
929 hotplug_status_changed,
930 "%s/%s", dev->nodename, "hotplug-status");
932 be->have_hotplug_status_watch = 1;
934 netif_tx_wake_all_queues(be->vif->dev);
939 if (be->vif->num_queues > 0)
940 xenvif_disconnect(be->vif); /* Clean up existing queues */
941 vfree(be->vif->queues);
942 be->vif->queues = NULL;
943 be->vif->num_queues = 0;
948 static int connect_rings(struct backend_info *be, struct xenvif_queue *queue)
950 struct xenbus_device *dev = be->dev;
951 unsigned int num_queues = queue->vif->num_queues;
952 unsigned long tx_ring_ref, rx_ring_ref;
953 unsigned int tx_evtchn, rx_evtchn;
957 const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */
959 /* If the frontend requested 1 queue, or we have fallen back
960 * to single queue due to lack of frontend support for multi-
961 * queue, expect the remaining XenStore keys in the toplevel
962 * directory. Otherwise, expect them in a subdirectory called
965 if (num_queues == 1) {
966 xspath = kzalloc(strlen(dev->otherend) + 1, GFP_KERNEL);
968 xenbus_dev_fatal(dev, -ENOMEM,
969 "reading ring references");
972 strcpy(xspath, dev->otherend);
974 xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
975 xspath = kzalloc(xspathsize, GFP_KERNEL);
977 xenbus_dev_fatal(dev, -ENOMEM,
978 "reading ring references");
981 snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend,
985 err = xenbus_gather(XBT_NIL, xspath,
986 "tx-ring-ref", "%lu", &tx_ring_ref,
987 "rx-ring-ref", "%lu", &rx_ring_ref, NULL);
989 xenbus_dev_fatal(dev, err,
990 "reading %s/ring-ref",
995 /* Try split event channels first, then single event channel. */
996 err = xenbus_gather(XBT_NIL, xspath,
997 "event-channel-tx", "%u", &tx_evtchn,
998 "event-channel-rx", "%u", &rx_evtchn, NULL);
1000 err = xenbus_scanf(XBT_NIL, xspath,
1001 "event-channel", "%u", &tx_evtchn);
1003 xenbus_dev_fatal(dev, err,
1004 "reading %s/event-channel(-tx/rx)",
1008 rx_evtchn = tx_evtchn;
1011 /* Map the shared frame, irq etc. */
1012 err = xenvif_connect(queue, tx_ring_ref, rx_ring_ref,
1013 tx_evtchn, rx_evtchn);
1015 xenbus_dev_fatal(dev, err,
1016 "mapping shared-frames %lu/%lu port tx %u rx %u",
1017 tx_ring_ref, rx_ring_ref,
1018 tx_evtchn, rx_evtchn);
1023 err: /* Regular return falls through with err == 0 */
1028 static int read_xenbus_vif_flags(struct backend_info *be)
1030 struct xenvif *vif = be->vif;
1031 struct xenbus_device *dev = be->dev;
1032 unsigned int rx_copy;
1035 err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
1037 if (err == -ENOENT) {
1042 xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy",
1049 if (xenbus_scanf(XBT_NIL, dev->otherend,
1050 "feature-rx-notify", "%d", &val) < 0)
1053 /* - Reduce drain timeout to poll more frequently for
1055 * - Disable Rx stall detection.
1057 be->vif->drain_timeout = msecs_to_jiffies(30);
1058 be->vif->stall_timeout = 0;
1061 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg",
1064 vif->can_sg = !!val;
1067 vif->gso_prefix_mask = 0;
1069 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4",
1073 vif->gso_mask |= GSO_BIT(TCPV4);
1075 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4-prefix",
1079 vif->gso_prefix_mask |= GSO_BIT(TCPV4);
1081 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv6",
1085 vif->gso_mask |= GSO_BIT(TCPV6);
1087 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv6-prefix",
1091 vif->gso_prefix_mask |= GSO_BIT(TCPV6);
1093 if (vif->gso_mask & vif->gso_prefix_mask) {
1094 xenbus_dev_fatal(dev, err,
1095 "%s: gso and gso prefix flags are not "
1096 "mutually exclusive",
1101 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload",
1104 vif->ip_csum = !val;
1106 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-ipv6-csum-offload",
1109 vif->ipv6_csum = !!val;
1114 static const struct xenbus_device_id netback_ids[] = {
1119 static struct xenbus_driver netback_driver = {
1121 .probe = netback_probe,
1122 .remove = netback_remove,
1123 .uevent = netback_uevent,
1124 .otherend_changed = frontend_changed,
1127 int xenvif_xenbus_init(void)
1129 return xenbus_register_backend(&netback_driver);
1132 void xenvif_xenbus_fini(void)
1134 return xenbus_unregister_driver(&netback_driver);