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 err
= xenbus_transaction_end(xbt
, 0);
331 } while (err
== -EAGAIN
);
334 xenbus_dev_fatal(dev
, err
, "completing transaction");
339 * Split event channels support, this is optional so it is not
340 * put inside the above loop.
342 err
= xenbus_printf(XBT_NIL
, dev
->nodename
,
343 "feature-split-event-channels",
344 "%u", separate_tx_rx_irq
);
346 pr_debug("Error writing feature-split-event-channels\n");
348 /* Multi-queue support: This is an optional feature. */
349 err
= xenbus_printf(XBT_NIL
, dev
->nodename
,
350 "multi-queue-max-queues", "%u", xenvif_max_queues
);
352 pr_debug("Error writing multi-queue-max-queues\n");
354 script
= xenbus_read(XBT_NIL
, dev
->nodename
, "script", NULL
);
355 if (IS_ERR(script
)) {
356 err
= PTR_ERR(script
);
357 xenbus_dev_fatal(dev
, err
, "reading script");
361 be
->hotplug_script
= script
;
363 err
= xenbus_switch_state(dev
, XenbusStateInitWait
);
367 be
->state
= XenbusStateInitWait
;
369 /* This kicks hotplug scripts, so do it immediately. */
370 err
= backend_create_xenvif(be
);
377 xenbus_transaction_end(xbt
, 1);
378 xenbus_dev_fatal(dev
, err
, "%s", message
);
380 pr_debug("failed\n");
387 * Handle the creation of the hotplug script environment. We add the script
388 * and vif variables to the environment, for the benefit of the vif-* hotplug
391 static int netback_uevent(struct xenbus_device
*xdev
,
392 struct kobj_uevent_env
*env
)
394 struct backend_info
*be
= dev_get_drvdata(&xdev
->dev
);
399 if (add_uevent_var(env
, "script=%s", be
->hotplug_script
))
405 return add_uevent_var(env
, "vif=%s", be
->vif
->dev
->name
);
409 static int backend_create_xenvif(struct backend_info
*be
)
413 struct xenbus_device
*dev
= be
->dev
;
419 err
= xenbus_scanf(XBT_NIL
, dev
->nodename
, "handle", "%li", &handle
);
421 xenbus_dev_fatal(dev
, err
, "reading handle");
422 return (err
< 0) ? err
: -EINVAL
;
425 vif
= xenvif_alloc(&dev
->dev
, dev
->otherend_id
, handle
);
428 xenbus_dev_fatal(dev
, err
, "creating interface");
433 kobject_uevent(&dev
->dev
.kobj
, KOBJ_ONLINE
);
437 static void backend_disconnect(struct backend_info
*be
)
440 xen_unregister_watchers(be
->vif
);
441 #ifdef CONFIG_DEBUG_FS
442 xenvif_debugfs_delif(be
->vif
);
443 #endif /* CONFIG_DEBUG_FS */
444 xenvif_disconnect(be
->vif
);
448 static void backend_connect(struct backend_info
*be
)
454 static inline void backend_switch_state(struct backend_info
*be
,
455 enum xenbus_state state
)
457 struct xenbus_device
*dev
= be
->dev
;
459 pr_debug("%s -> %s\n", dev
->nodename
, xenbus_strstate(state
));
462 /* If we are waiting for a hotplug script then defer the
463 * actual xenbus state change.
465 if (!be
->have_hotplug_status_watch
)
466 xenbus_switch_state(dev
, state
);
469 /* Handle backend state transitions:
471 * The backend state starts in InitWait and the following transitions are
474 * InitWait -> Connected
486 * The state argument specifies the eventual state of the backend and the
487 * function transitions to that state via the shortest path.
489 static void set_backend_state(struct backend_info
*be
,
490 enum xenbus_state state
)
492 while (be
->state
!= state
) {
494 case XenbusStateClosed
:
496 case XenbusStateInitWait
:
497 case XenbusStateConnected
:
498 pr_info("%s: prepare for reconnect\n",
500 backend_switch_state(be
, XenbusStateInitWait
);
502 case XenbusStateClosing
:
503 backend_switch_state(be
, XenbusStateClosing
);
509 case XenbusStateInitWait
:
511 case XenbusStateConnected
:
513 backend_switch_state(be
, XenbusStateConnected
);
515 case XenbusStateClosing
:
516 case XenbusStateClosed
:
517 backend_switch_state(be
, XenbusStateClosing
);
523 case XenbusStateConnected
:
525 case XenbusStateInitWait
:
526 case XenbusStateClosing
:
527 case XenbusStateClosed
:
528 backend_disconnect(be
);
529 backend_switch_state(be
, XenbusStateClosing
);
535 case XenbusStateClosing
:
537 case XenbusStateInitWait
:
538 case XenbusStateConnected
:
539 case XenbusStateClosed
:
540 backend_switch_state(be
, XenbusStateClosed
);
553 * Callback received when the frontend's state changes.
555 static void frontend_changed(struct xenbus_device
*dev
,
556 enum xenbus_state frontend_state
)
558 struct backend_info
*be
= dev_get_drvdata(&dev
->dev
);
560 pr_debug("%s -> %s\n", dev
->otherend
, xenbus_strstate(frontend_state
));
562 be
->frontend_state
= frontend_state
;
564 switch (frontend_state
) {
565 case XenbusStateInitialising
:
566 set_backend_state(be
, XenbusStateInitWait
);
569 case XenbusStateInitialised
:
572 case XenbusStateConnected
:
573 set_backend_state(be
, XenbusStateConnected
);
576 case XenbusStateClosing
:
577 set_backend_state(be
, XenbusStateClosing
);
580 case XenbusStateClosed
:
581 set_backend_state(be
, XenbusStateClosed
);
582 if (xenbus_dev_is_online(dev
))
584 /* fall through if not online */
585 case XenbusStateUnknown
:
586 set_backend_state(be
, XenbusStateClosed
);
587 device_unregister(&dev
->dev
);
591 xenbus_dev_fatal(dev
, -EINVAL
, "saw state %d at frontend",
598 static void xen_net_read_rate(struct xenbus_device
*dev
,
599 unsigned long *bytes
, unsigned long *usec
)
605 /* Default to unlimited bandwidth. */
609 ratestr
= xenbus_read(XBT_NIL
, dev
->nodename
, "rate", NULL
);
614 b
= simple_strtoul(s
, &e
, 10);
615 if ((s
== e
) || (*e
!= ','))
619 u
= simple_strtoul(s
, &e
, 10);
620 if ((s
== e
) || (*e
!= '\0'))
630 pr_warn("Failed to parse network rate limit. Traffic unlimited.\n");
634 static int xen_net_read_mac(struct xenbus_device
*dev
, u8 mac
[])
636 char *s
, *e
, *macstr
;
639 macstr
= s
= xenbus_read(XBT_NIL
, dev
->nodename
, "mac", NULL
);
641 return PTR_ERR(macstr
);
643 for (i
= 0; i
< ETH_ALEN
; i
++) {
644 mac
[i
] = simple_strtoul(s
, &e
, 16);
645 if ((s
== e
) || (*e
!= ((i
== ETH_ALEN
-1) ? '\0' : ':'))) {
656 static void xen_net_rate_changed(struct xenbus_watch
*watch
,
657 const char **vec
, unsigned int len
)
659 struct xenvif
*vif
= container_of(watch
, struct xenvif
, credit_watch
);
660 struct xenbus_device
*dev
= xenvif_to_xenbus_device(vif
);
661 unsigned long credit_bytes
;
662 unsigned long credit_usec
;
663 unsigned int queue_index
;
665 xen_net_read_rate(dev
, &credit_bytes
, &credit_usec
);
666 for (queue_index
= 0; queue_index
< vif
->num_queues
; queue_index
++) {
667 struct xenvif_queue
*queue
= &vif
->queues
[queue_index
];
669 queue
->credit_bytes
= credit_bytes
;
670 queue
->credit_usec
= credit_usec
;
671 if (!mod_timer_pending(&queue
->credit_timeout
, jiffies
) &&
672 queue
->remaining_credit
> queue
->credit_bytes
) {
673 queue
->remaining_credit
= queue
->credit_bytes
;
678 static int xen_register_watchers(struct xenbus_device
*dev
, struct xenvif
*vif
)
682 unsigned maxlen
= strlen(dev
->nodename
) + sizeof("/rate");
684 if (vif
->credit_watch
.node
)
687 node
= kmalloc(maxlen
, GFP_KERNEL
);
690 snprintf(node
, maxlen
, "%s/rate", dev
->nodename
);
691 vif
->credit_watch
.node
= node
;
692 vif
->credit_watch
.callback
= xen_net_rate_changed
;
693 err
= register_xenbus_watch(&vif
->credit_watch
);
695 pr_err("Failed to set watcher %s\n", vif
->credit_watch
.node
);
697 vif
->credit_watch
.node
= NULL
;
698 vif
->credit_watch
.callback
= NULL
;
703 static void xen_unregister_watchers(struct xenvif
*vif
)
705 if (vif
->credit_watch
.node
) {
706 unregister_xenbus_watch(&vif
->credit_watch
);
707 kfree(vif
->credit_watch
.node
);
708 vif
->credit_watch
.node
= NULL
;
712 static void unregister_hotplug_status_watch(struct backend_info
*be
)
714 if (be
->have_hotplug_status_watch
) {
715 unregister_xenbus_watch(&be
->hotplug_status_watch
);
716 kfree(be
->hotplug_status_watch
.node
);
718 be
->have_hotplug_status_watch
= 0;
721 static void hotplug_status_changed(struct xenbus_watch
*watch
,
723 unsigned int vec_size
)
725 struct backend_info
*be
= container_of(watch
,
727 hotplug_status_watch
);
731 str
= xenbus_read(XBT_NIL
, be
->dev
->nodename
, "hotplug-status", &len
);
734 if (len
== sizeof("connected")-1 && !memcmp(str
, "connected", len
)) {
735 /* Complete any pending state change */
736 xenbus_switch_state(be
->dev
, be
->state
);
738 /* Not interested in this watch anymore. */
739 unregister_hotplug_status_watch(be
);
744 static void connect(struct backend_info
*be
)
747 struct xenbus_device
*dev
= be
->dev
;
748 unsigned long credit_bytes
, credit_usec
;
749 unsigned int queue_index
;
750 unsigned int requested_num_queues
;
751 struct xenvif_queue
*queue
;
753 /* Check whether the frontend requested multiple queues
754 * and read the number requested.
756 err
= xenbus_scanf(XBT_NIL
, dev
->otherend
,
757 "multi-queue-num-queues",
758 "%u", &requested_num_queues
);
760 requested_num_queues
= 1; /* Fall back to single queue */
761 } else if (requested_num_queues
> xenvif_max_queues
) {
762 /* buggy or malicious guest */
763 xenbus_dev_fatal(dev
, err
,
764 "guest requested %u queues, exceeding the maximum of %u.",
765 requested_num_queues
, xenvif_max_queues
);
769 err
= xen_net_read_mac(dev
, be
->vif
->fe_dev_addr
);
771 xenbus_dev_fatal(dev
, err
, "parsing %s/mac", dev
->nodename
);
775 xen_net_read_rate(dev
, &credit_bytes
, &credit_usec
);
776 xen_unregister_watchers(be
->vif
);
777 xen_register_watchers(dev
, be
->vif
);
778 read_xenbus_vif_flags(be
);
780 /* Use the number of queues requested by the frontend */
781 be
->vif
->queues
= vzalloc(requested_num_queues
*
782 sizeof(struct xenvif_queue
));
783 be
->vif
->num_queues
= requested_num_queues
;
784 be
->vif
->stalled_queues
= requested_num_queues
;
786 for (queue_index
= 0; queue_index
< requested_num_queues
; ++queue_index
) {
787 queue
= &be
->vif
->queues
[queue_index
];
788 queue
->vif
= be
->vif
;
789 queue
->id
= queue_index
;
790 snprintf(queue
->name
, sizeof(queue
->name
), "%s-q%u",
791 be
->vif
->dev
->name
, queue
->id
);
793 err
= xenvif_init_queue(queue
);
795 /* xenvif_init_queue() cleans up after itself on
796 * failure, but we need to clean up any previously
797 * initialised queues. Set num_queues to i so that
798 * earlier queues can be destroyed using the regular
801 be
->vif
->num_queues
= queue_index
;
805 queue
->credit_bytes
= credit_bytes
;
806 queue
->remaining_credit
= credit_bytes
;
807 queue
->credit_usec
= credit_usec
;
809 err
= connect_rings(be
, queue
);
811 /* connect_rings() cleans up after itself on failure,
812 * but we need to clean up after xenvif_init_queue() here,
813 * and also clean up any previously initialised queues.
815 xenvif_deinit_queue(queue
);
816 be
->vif
->num_queues
= queue_index
;
821 #ifdef CONFIG_DEBUG_FS
822 xenvif_debugfs_addif(be
->vif
);
823 #endif /* CONFIG_DEBUG_FS */
825 /* Initialisation completed, tell core driver the number of
829 netif_set_real_num_tx_queues(be
->vif
->dev
, requested_num_queues
);
830 netif_set_real_num_rx_queues(be
->vif
->dev
, requested_num_queues
);
833 xenvif_carrier_on(be
->vif
);
835 unregister_hotplug_status_watch(be
);
836 err
= xenbus_watch_pathfmt(dev
, &be
->hotplug_status_watch
,
837 hotplug_status_changed
,
838 "%s/%s", dev
->nodename
, "hotplug-status");
840 be
->have_hotplug_status_watch
= 1;
842 netif_tx_wake_all_queues(be
->vif
->dev
);
847 if (be
->vif
->num_queues
> 0)
848 xenvif_disconnect(be
->vif
); /* Clean up existing queues */
849 vfree(be
->vif
->queues
);
850 be
->vif
->queues
= NULL
;
851 be
->vif
->num_queues
= 0;
856 static int connect_rings(struct backend_info
*be
, struct xenvif_queue
*queue
)
858 struct xenbus_device
*dev
= be
->dev
;
859 unsigned int num_queues
= queue
->vif
->num_queues
;
860 unsigned long tx_ring_ref
, rx_ring_ref
;
861 unsigned int tx_evtchn
, rx_evtchn
;
865 const size_t xenstore_path_ext_size
= 11; /* sufficient for "/queue-NNN" */
867 /* If the frontend requested 1 queue, or we have fallen back
868 * to single queue due to lack of frontend support for multi-
869 * queue, expect the remaining XenStore keys in the toplevel
870 * directory. Otherwise, expect them in a subdirectory called
873 if (num_queues
== 1) {
874 xspath
= kzalloc(strlen(dev
->otherend
) + 1, GFP_KERNEL
);
876 xenbus_dev_fatal(dev
, -ENOMEM
,
877 "reading ring references");
880 strcpy(xspath
, dev
->otherend
);
882 xspathsize
= strlen(dev
->otherend
) + xenstore_path_ext_size
;
883 xspath
= kzalloc(xspathsize
, GFP_KERNEL
);
885 xenbus_dev_fatal(dev
, -ENOMEM
,
886 "reading ring references");
889 snprintf(xspath
, xspathsize
, "%s/queue-%u", dev
->otherend
,
893 err
= xenbus_gather(XBT_NIL
, xspath
,
894 "tx-ring-ref", "%lu", &tx_ring_ref
,
895 "rx-ring-ref", "%lu", &rx_ring_ref
, NULL
);
897 xenbus_dev_fatal(dev
, err
,
898 "reading %s/ring-ref",
903 /* Try split event channels first, then single event channel. */
904 err
= xenbus_gather(XBT_NIL
, xspath
,
905 "event-channel-tx", "%u", &tx_evtchn
,
906 "event-channel-rx", "%u", &rx_evtchn
, NULL
);
908 err
= xenbus_scanf(XBT_NIL
, xspath
,
909 "event-channel", "%u", &tx_evtchn
);
911 xenbus_dev_fatal(dev
, err
,
912 "reading %s/event-channel(-tx/rx)",
916 rx_evtchn
= tx_evtchn
;
919 /* Map the shared frame, irq etc. */
920 err
= xenvif_connect(queue
, tx_ring_ref
, rx_ring_ref
,
921 tx_evtchn
, rx_evtchn
);
923 xenbus_dev_fatal(dev
, err
,
924 "mapping shared-frames %lu/%lu port tx %u rx %u",
925 tx_ring_ref
, rx_ring_ref
,
926 tx_evtchn
, rx_evtchn
);
931 err
: /* Regular return falls through with err == 0 */
936 static int read_xenbus_vif_flags(struct backend_info
*be
)
938 struct xenvif
*vif
= be
->vif
;
939 struct xenbus_device
*dev
= be
->dev
;
940 unsigned int rx_copy
;
943 err
= xenbus_scanf(XBT_NIL
, dev
->otherend
, "request-rx-copy", "%u",
945 if (err
== -ENOENT
) {
950 xenbus_dev_fatal(dev
, err
, "reading %s/request-rx-copy",
957 if (xenbus_scanf(XBT_NIL
, dev
->otherend
,
958 "feature-rx-notify", "%d", &val
) < 0)
961 /* - Reduce drain timeout to poll more frequently for
963 * - Disable Rx stall detection.
965 be
->vif
->drain_timeout
= msecs_to_jiffies(30);
966 be
->vif
->stall_timeout
= 0;
969 if (xenbus_scanf(XBT_NIL
, dev
->otherend
, "feature-sg",
975 vif
->gso_prefix_mask
= 0;
977 if (xenbus_scanf(XBT_NIL
, dev
->otherend
, "feature-gso-tcpv4",
981 vif
->gso_mask
|= GSO_BIT(TCPV4
);
983 if (xenbus_scanf(XBT_NIL
, dev
->otherend
, "feature-gso-tcpv4-prefix",
987 vif
->gso_prefix_mask
|= GSO_BIT(TCPV4
);
989 if (xenbus_scanf(XBT_NIL
, dev
->otherend
, "feature-gso-tcpv6",
993 vif
->gso_mask
|= GSO_BIT(TCPV6
);
995 if (xenbus_scanf(XBT_NIL
, dev
->otherend
, "feature-gso-tcpv6-prefix",
999 vif
->gso_prefix_mask
|= GSO_BIT(TCPV6
);
1001 if (vif
->gso_mask
& vif
->gso_prefix_mask
) {
1002 xenbus_dev_fatal(dev
, err
,
1003 "%s: gso and gso prefix flags are not "
1004 "mutually exclusive",
1009 if (xenbus_scanf(XBT_NIL
, dev
->otherend
, "feature-no-csum-offload",
1012 vif
->ip_csum
= !val
;
1014 if (xenbus_scanf(XBT_NIL
, dev
->otherend
, "feature-ipv6-csum-offload",
1017 vif
->ipv6_csum
= !!val
;
1022 static const struct xenbus_device_id netback_ids
[] = {
1027 static struct xenbus_driver netback_driver
= {
1029 .probe
= netback_probe
,
1030 .remove
= netback_remove
,
1031 .uevent
= netback_uevent
,
1032 .otherend_changed
= frontend_changed
,
1035 int xenvif_xenbus_init(void)
1037 return xenbus_register_backend(&netback_driver
);
1040 void xenvif_xenbus_fini(void)
1042 return xenbus_unregister_driver(&netback_driver
);