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1/******************************************************************************
2 * Client-facing interface for the Xenbus driver. In other words, the
3 * interface between the Xenbus and the device-specific code, be it the
4 * frontend or the backend of that driver.
5 *
6 * Copyright (C) 2005 XenSource Ltd
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License version 2
10 * as published by the Free Software Foundation; or, when distributed
11 * separately from the Linux kernel or incorporated into other
12 * software packages, subject to the following license:
13 *
14 * Permission is hereby granted, free of charge, to any person obtaining a copy
15 * of this source file (the "Software"), to deal in the Software without
16 * restriction, including without limitation the rights to use, copy, modify,
17 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
18 * and to permit persons to whom the Software is furnished to do so, subject to
19 * the following conditions:
20 *
21 * The above copyright notice and this permission notice shall be included in
22 * all copies or substantial portions of the Software.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
29 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
30 * IN THE SOFTWARE.
31 */
32
33#include <linux/slab.h>
34#include <linux/types.h>
35#include <linux/spinlock.h>
36#include <linux/vmalloc.h>
37#include <linux/export.h>
38#include <asm/xen/hypervisor.h>
39#include <asm/xen/page.h>
40#include <xen/interface/xen.h>
41#include <xen/interface/event_channel.h>
42#include <xen/balloon.h>
43#include <xen/events.h>
44#include <xen/grant_table.h>
45#include <xen/xenbus.h>
46#include <xen/xen.h>
47
48#include "xenbus_probe.h"
49
50struct xenbus_map_node {
51 struct list_head next;
52 union {
53 struct vm_struct *area; /* PV */
54 struct page *page; /* HVM */
55 };
56 grant_handle_t handle;
57};
58
59static DEFINE_SPINLOCK(xenbus_valloc_lock);
60static LIST_HEAD(xenbus_valloc_pages);
61
62struct xenbus_ring_ops {
63 int (*map)(struct xenbus_device *dev, int gnt, void **vaddr);
64 int (*unmap)(struct xenbus_device *dev, void *vaddr);
65};
66
67static const struct xenbus_ring_ops *ring_ops __read_mostly;
68
69const char *xenbus_strstate(enum xenbus_state state)
70{
71 static const char *const name[] = {
72 [ XenbusStateUnknown ] = "Unknown",
73 [ XenbusStateInitialising ] = "Initialising",
74 [ XenbusStateInitWait ] = "InitWait",
75 [ XenbusStateInitialised ] = "Initialised",
76 [ XenbusStateConnected ] = "Connected",
77 [ XenbusStateClosing ] = "Closing",
78 [ XenbusStateClosed ] = "Closed",
79 [XenbusStateReconfiguring] = "Reconfiguring",
80 [XenbusStateReconfigured] = "Reconfigured",
81 };
82 return (state < ARRAY_SIZE(name)) ? name[state] : "INVALID";
83}
84EXPORT_SYMBOL_GPL(xenbus_strstate);
85
86/**
87 * xenbus_watch_path - register a watch
88 * @dev: xenbus device
89 * @path: path to watch
90 * @watch: watch to register
91 * @callback: callback to register
92 *
93 * Register a @watch on the given path, using the given xenbus_watch structure
94 * for storage, and the given @callback function as the callback. Return 0 on
95 * success, or -errno on error. On success, the given @path will be saved as
96 * @watch->node, and remains the caller's to free. On error, @watch->node will
97 * be NULL, the device will switch to %XenbusStateClosing, and the error will
98 * be saved in the store.
99 */
100int xenbus_watch_path(struct xenbus_device *dev, const char *path,
101 struct xenbus_watch *watch,
102 void (*callback)(struct xenbus_watch *,
103 const char **, unsigned int))
104{
105 int err;
106
107 watch->node = path;
108 watch->callback = callback;
109
110 err = register_xenbus_watch(watch);
111
112 if (err) {
113 watch->node = NULL;
114 watch->callback = NULL;
115 xenbus_dev_fatal(dev, err, "adding watch on %s", path);
116 }
117
118 return err;
119}
120EXPORT_SYMBOL_GPL(xenbus_watch_path);
121
122
123/**
124 * xenbus_watch_pathfmt - register a watch on a sprintf-formatted path
125 * @dev: xenbus device
126 * @watch: watch to register
127 * @callback: callback to register
128 * @pathfmt: format of path to watch
129 *
130 * Register a watch on the given @path, using the given xenbus_watch
131 * structure for storage, and the given @callback function as the callback.
132 * Return 0 on success, or -errno on error. On success, the watched path
133 * (@path/@path2) will be saved as @watch->node, and becomes the caller's to
134 * kfree(). On error, watch->node will be NULL, so the caller has nothing to
135 * free, the device will switch to %XenbusStateClosing, and the error will be
136 * saved in the store.
137 */
138int xenbus_watch_pathfmt(struct xenbus_device *dev,
139 struct xenbus_watch *watch,
140 void (*callback)(struct xenbus_watch *,
141 const char **, unsigned int),
142 const char *pathfmt, ...)
143{
144 int err;
145 va_list ap;
146 char *path;
147
148 va_start(ap, pathfmt);
149 path = kvasprintf(GFP_NOIO | __GFP_HIGH, pathfmt, ap);
150 va_end(ap);
151
152 if (!path) {
153 xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch");
154 return -ENOMEM;
155 }
156 err = xenbus_watch_path(dev, path, watch, callback);
157
158 if (err)
159 kfree(path);
160 return err;
161}
162EXPORT_SYMBOL_GPL(xenbus_watch_pathfmt);
163
164static void xenbus_switch_fatal(struct xenbus_device *, int, int,
165 const char *, ...);
166
167static int
168__xenbus_switch_state(struct xenbus_device *dev,
169 enum xenbus_state state, int depth)
170{
171 /* We check whether the state is currently set to the given value, and
172 if not, then the state is set. We don't want to unconditionally
173 write the given state, because we don't want to fire watches
174 unnecessarily. Furthermore, if the node has gone, we don't write
175 to it, as the device will be tearing down, and we don't want to
176 resurrect that directory.
177
178 Note that, because of this cached value of our state, this
179 function will not take a caller's Xenstore transaction
180 (something it was trying to in the past) because dev->state
181 would not get reset if the transaction was aborted.
182 */
183
184 struct xenbus_transaction xbt;
185 int current_state;
186 int err, abort;
187
188 if (state == dev->state)
189 return 0;
190
191again:
192 abort = 1;
193
194 err = xenbus_transaction_start(&xbt);
195 if (err) {
196 xenbus_switch_fatal(dev, depth, err, "starting transaction");
197 return 0;
198 }
199
200 err = xenbus_scanf(xbt, dev->nodename, "state", "%d", ¤t_state);
201 if (err != 1)
202 goto abort;
203
204 err = xenbus_printf(xbt, dev->nodename, "state", "%d", state);
205 if (err) {
206 xenbus_switch_fatal(dev, depth, err, "writing new state");
207 goto abort;
208 }
209
210 abort = 0;
211abort:
212 err = xenbus_transaction_end(xbt, abort);
213 if (err) {
214 if (err == -EAGAIN && !abort)
215 goto again;
216 xenbus_switch_fatal(dev, depth, err, "ending transaction");
217 } else
218 dev->state = state;
219
220 return 0;
221}
222
223/**
224 * xenbus_switch_state
225 * @dev: xenbus device
226 * @state: new state
227 *
228 * Advertise in the store a change of the given driver to the given new_state.
229 * Return 0 on success, or -errno on error. On error, the device will switch
230 * to XenbusStateClosing, and the error will be saved in the store.
231 */
232int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state)
233{
234 return __xenbus_switch_state(dev, state, 0);
235}
236
237EXPORT_SYMBOL_GPL(xenbus_switch_state);
238
239int xenbus_frontend_closed(struct xenbus_device *dev)
240{
241 xenbus_switch_state(dev, XenbusStateClosed);
242 complete(&dev->down);
243 return 0;
244}
245EXPORT_SYMBOL_GPL(xenbus_frontend_closed);
246
247/**
248 * Return the path to the error node for the given device, or NULL on failure.
249 * If the value returned is non-NULL, then it is the caller's to kfree.
250 */
251static char *error_path(struct xenbus_device *dev)
252{
253 return kasprintf(GFP_KERNEL, "error/%s", dev->nodename);
254}
255
256
257static void xenbus_va_dev_error(struct xenbus_device *dev, int err,
258 const char *fmt, va_list ap)
259{
260 int ret;
261 unsigned int len;
262 char *printf_buffer = NULL;
263 char *path_buffer = NULL;
264
265#define PRINTF_BUFFER_SIZE 4096
266 printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL);
267 if (printf_buffer == NULL)
268 goto fail;
269
270 len = sprintf(printf_buffer, "%i ", -err);
271 ret = vsnprintf(printf_buffer+len, PRINTF_BUFFER_SIZE-len, fmt, ap);
272
273 BUG_ON(len + ret > PRINTF_BUFFER_SIZE-1);
274
275 dev_err(&dev->dev, "%s\n", printf_buffer);
276
277 path_buffer = error_path(dev);
278
279 if (path_buffer == NULL) {
280 dev_err(&dev->dev, "failed to write error node for %s (%s)\n",
281 dev->nodename, printf_buffer);
282 goto fail;
283 }
284
285 if (xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer) != 0) {
286 dev_err(&dev->dev, "failed to write error node for %s (%s)\n",
287 dev->nodename, printf_buffer);
288 goto fail;
289 }
290
291fail:
292 kfree(printf_buffer);
293 kfree(path_buffer);
294}
295
296
297/**
298 * xenbus_dev_error
299 * @dev: xenbus device
300 * @err: error to report
301 * @fmt: error message format
302 *
303 * Report the given negative errno into the store, along with the given
304 * formatted message.
305 */
306void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...)
307{
308 va_list ap;
309
310 va_start(ap, fmt);
311 xenbus_va_dev_error(dev, err, fmt, ap);
312 va_end(ap);
313}
314EXPORT_SYMBOL_GPL(xenbus_dev_error);
315
316/**
317 * xenbus_dev_fatal
318 * @dev: xenbus device
319 * @err: error to report
320 * @fmt: error message format
321 *
322 * Equivalent to xenbus_dev_error(dev, err, fmt, args), followed by
323 * xenbus_switch_state(dev, XenbusStateClosing) to schedule an orderly
324 * closedown of this driver and its peer.
325 */
326
327void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...)
328{
329 va_list ap;
330
331 va_start(ap, fmt);
332 xenbus_va_dev_error(dev, err, fmt, ap);
333 va_end(ap);
334
335 xenbus_switch_state(dev, XenbusStateClosing);
336}
337EXPORT_SYMBOL_GPL(xenbus_dev_fatal);
338
339/**
340 * Equivalent to xenbus_dev_fatal(dev, err, fmt, args), but helps
341 * avoiding recursion within xenbus_switch_state.
342 */
343static void xenbus_switch_fatal(struct xenbus_device *dev, int depth, int err,
344 const char *fmt, ...)
345{
346 va_list ap;
347
348 va_start(ap, fmt);
349 xenbus_va_dev_error(dev, err, fmt, ap);
350 va_end(ap);
351
352 if (!depth)
353 __xenbus_switch_state(dev, XenbusStateClosing, 1);
354}
355
356/**
357 * xenbus_grant_ring
358 * @dev: xenbus device
359 * @ring_mfn: mfn of ring to grant
360
361 * Grant access to the given @ring_mfn to the peer of the given device. Return
362 * 0 on success, or -errno on error. On error, the device will switch to
363 * XenbusStateClosing, and the error will be saved in the store.
364 */
365int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn)
366{
367 int err = gnttab_grant_foreign_access(dev->otherend_id, ring_mfn, 0);
368 if (err < 0)
369 xenbus_dev_fatal(dev, err, "granting access to ring page");
370 return err;
371}
372EXPORT_SYMBOL_GPL(xenbus_grant_ring);
373
374
375/**
376 * Allocate an event channel for the given xenbus_device, assigning the newly
377 * created local port to *port. Return 0 on success, or -errno on error. On
378 * error, the device will switch to XenbusStateClosing, and the error will be
379 * saved in the store.
380 */
381int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port)
382{
383 struct evtchn_alloc_unbound alloc_unbound;
384 int err;
385
386 alloc_unbound.dom = DOMID_SELF;
387 alloc_unbound.remote_dom = dev->otherend_id;
388
389 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
390 &alloc_unbound);
391 if (err)
392 xenbus_dev_fatal(dev, err, "allocating event channel");
393 else
394 *port = alloc_unbound.port;
395
396 return err;
397}
398EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn);
399
400
401/**
402 * Bind to an existing interdomain event channel in another domain. Returns 0
403 * on success and stores the local port in *port. On error, returns -errno,
404 * switches the device to XenbusStateClosing, and saves the error in XenStore.
405 */
406int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port)
407{
408 struct evtchn_bind_interdomain bind_interdomain;
409 int err;
410
411 bind_interdomain.remote_dom = dev->otherend_id;
412 bind_interdomain.remote_port = remote_port;
413
414 err = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
415 &bind_interdomain);
416 if (err)
417 xenbus_dev_fatal(dev, err,
418 "binding to event channel %d from domain %d",
419 remote_port, dev->otherend_id);
420 else
421 *port = bind_interdomain.local_port;
422
423 return err;
424}
425EXPORT_SYMBOL_GPL(xenbus_bind_evtchn);
426
427
428/**
429 * Free an existing event channel. Returns 0 on success or -errno on error.
430 */
431int xenbus_free_evtchn(struct xenbus_device *dev, int port)
432{
433 struct evtchn_close close;
434 int err;
435
436 close.port = port;
437
438 err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
439 if (err)
440 xenbus_dev_error(dev, err, "freeing event channel %d", port);
441
442 return err;
443}
444EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
445
446
447/**
448 * xenbus_map_ring_valloc
449 * @dev: xenbus device
450 * @gnt_ref: grant reference
451 * @vaddr: pointer to address to be filled out by mapping
452 *
453 * Based on Rusty Russell's skeleton driver's map_page.
454 * Map a page of memory into this domain from another domain's grant table.
455 * xenbus_map_ring_valloc allocates a page of virtual address space, maps the
456 * page to that address, and sets *vaddr to that address.
457 * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
458 * or -ENOMEM on error. If an error is returned, device will switch to
459 * XenbusStateClosing and the error message will be saved in XenStore.
460 */
461int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void **vaddr)
462{
463 return ring_ops->map(dev, gnt_ref, vaddr);
464}
465EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);
466
467static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
468 int gnt_ref, void **vaddr)
469{
470 struct gnttab_map_grant_ref op = {
471 .flags = GNTMAP_host_map | GNTMAP_contains_pte,
472 .ref = gnt_ref,
473 .dom = dev->otherend_id,
474 };
475 struct xenbus_map_node *node;
476 struct vm_struct *area;
477 pte_t *pte;
478
479 *vaddr = NULL;
480
481 node = kzalloc(sizeof(*node), GFP_KERNEL);
482 if (!node)
483 return -ENOMEM;
484
485 area = alloc_vm_area(PAGE_SIZE, &pte);
486 if (!area) {
487 kfree(node);
488 return -ENOMEM;
489 }
490
491 op.host_addr = arbitrary_virt_to_machine(pte).maddr;
492
493 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
494 BUG();
495
496 if (op.status != GNTST_okay) {
497 free_vm_area(area);
498 kfree(node);
499 xenbus_dev_fatal(dev, op.status,
500 "mapping in shared page %d from domain %d",
501 gnt_ref, dev->otherend_id);
502 return op.status;
503 }
504
505 node->handle = op.handle;
506 node->area = area;
507
508 spin_lock(&xenbus_valloc_lock);
509 list_add(&node->next, &xenbus_valloc_pages);
510 spin_unlock(&xenbus_valloc_lock);
511
512 *vaddr = area->addr;
513 return 0;
514}
515
516static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
517 int gnt_ref, void **vaddr)
518{
519 struct xenbus_map_node *node;
520 int err;
521 void *addr;
522
523 *vaddr = NULL;
524
525 node = kzalloc(sizeof(*node), GFP_KERNEL);
526 if (!node)
527 return -ENOMEM;
528
529 err = alloc_xenballooned_pages(1, &node->page, false /* lowmem */);
530 if (err)
531 goto out_err;
532
533 addr = pfn_to_kaddr(page_to_pfn(node->page));
534
535 err = xenbus_map_ring(dev, gnt_ref, &node->handle, addr);
536 if (err)
537 goto out_err;
538
539 spin_lock(&xenbus_valloc_lock);
540 list_add(&node->next, &xenbus_valloc_pages);
541 spin_unlock(&xenbus_valloc_lock);
542
543 *vaddr = addr;
544 return 0;
545
546 out_err:
547 free_xenballooned_pages(1, &node->page);
548 kfree(node);
549 return err;
550}
551
552
553/**
554 * xenbus_map_ring
555 * @dev: xenbus device
556 * @gnt_ref: grant reference
557 * @handle: pointer to grant handle to be filled
558 * @vaddr: address to be mapped to
559 *
560 * Map a page of memory into this domain from another domain's grant table.
561 * xenbus_map_ring does not allocate the virtual address space (you must do
562 * this yourself!). It only maps in the page to the specified address.
563 * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
564 * or -ENOMEM on error. If an error is returned, device will switch to
565 * XenbusStateClosing and the error message will be saved in XenStore.
566 */
567int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
568 grant_handle_t *handle, void *vaddr)
569{
570 struct gnttab_map_grant_ref op;
571
572 gnttab_set_map_op(&op, (unsigned long)vaddr, GNTMAP_host_map, gnt_ref,
573 dev->otherend_id);
574
575 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
576 BUG();
577
578 if (op.status != GNTST_okay) {
579 xenbus_dev_fatal(dev, op.status,
580 "mapping in shared page %d from domain %d",
581 gnt_ref, dev->otherend_id);
582 } else
583 *handle = op.handle;
584
585 return op.status;
586}
587EXPORT_SYMBOL_GPL(xenbus_map_ring);
588
589
590/**
591 * xenbus_unmap_ring_vfree
592 * @dev: xenbus device
593 * @vaddr: addr to unmap
594 *
595 * Based on Rusty Russell's skeleton driver's unmap_page.
596 * Unmap a page of memory in this domain that was imported from another domain.
597 * Use xenbus_unmap_ring_vfree if you mapped in your memory with
598 * xenbus_map_ring_valloc (it will free the virtual address space).
599 * Returns 0 on success and returns GNTST_* on error
600 * (see xen/include/interface/grant_table.h).
601 */
602int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
603{
604 return ring_ops->unmap(dev, vaddr);
605}
606EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree);
607
608static int xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev, void *vaddr)
609{
610 struct xenbus_map_node *node;
611 struct gnttab_unmap_grant_ref op = {
612 .host_addr = (unsigned long)vaddr,
613 };
614 unsigned int level;
615
616 spin_lock(&xenbus_valloc_lock);
617 list_for_each_entry(node, &xenbus_valloc_pages, next) {
618 if (node->area->addr == vaddr) {
619 list_del(&node->next);
620 goto found;
621 }
622 }
623 node = NULL;
624 found:
625 spin_unlock(&xenbus_valloc_lock);
626
627 if (!node) {
628 xenbus_dev_error(dev, -ENOENT,
629 "can't find mapped virtual address %p", vaddr);
630 return GNTST_bad_virt_addr;
631 }
632
633 op.handle = node->handle;
634 op.host_addr = arbitrary_virt_to_machine(
635 lookup_address((unsigned long)vaddr, &level)).maddr;
636
637 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
638 BUG();
639
640 if (op.status == GNTST_okay)
641 free_vm_area(node->area);
642 else
643 xenbus_dev_error(dev, op.status,
644 "unmapping page at handle %d error %d",
645 node->handle, op.status);
646
647 kfree(node);
648 return op.status;
649}
650
651static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
652{
653 int rv;
654 struct xenbus_map_node *node;
655 void *addr;
656
657 spin_lock(&xenbus_valloc_lock);
658 list_for_each_entry(node, &xenbus_valloc_pages, next) {
659 addr = pfn_to_kaddr(page_to_pfn(node->page));
660 if (addr == vaddr) {
661 list_del(&node->next);
662 goto found;
663 }
664 }
665 node = addr = NULL;
666 found:
667 spin_unlock(&xenbus_valloc_lock);
668
669 if (!node) {
670 xenbus_dev_error(dev, -ENOENT,
671 "can't find mapped virtual address %p", vaddr);
672 return GNTST_bad_virt_addr;
673 }
674
675 rv = xenbus_unmap_ring(dev, node->handle, addr);
676
677 if (!rv)
678 free_xenballooned_pages(1, &node->page);
679 else
680 WARN(1, "Leaking %p\n", vaddr);
681
682 kfree(node);
683 return rv;
684}
685
686/**
687 * xenbus_unmap_ring
688 * @dev: xenbus device
689 * @handle: grant handle
690 * @vaddr: addr to unmap
691 *
692 * Unmap a page of memory in this domain that was imported from another domain.
693 * Returns 0 on success and returns GNTST_* on error
694 * (see xen/include/interface/grant_table.h).
695 */
696int xenbus_unmap_ring(struct xenbus_device *dev,
697 grant_handle_t handle, void *vaddr)
698{
699 struct gnttab_unmap_grant_ref op;
700
701 gnttab_set_unmap_op(&op, (unsigned long)vaddr, GNTMAP_host_map, handle);
702
703 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
704 BUG();
705
706 if (op.status != GNTST_okay)
707 xenbus_dev_error(dev, op.status,
708 "unmapping page at handle %d error %d",
709 handle, op.status);
710
711 return op.status;
712}
713EXPORT_SYMBOL_GPL(xenbus_unmap_ring);
714
715
716/**
717 * xenbus_read_driver_state
718 * @path: path for driver
719 *
720 * Return the state of the driver rooted at the given store path, or
721 * XenbusStateUnknown if no state can be read.
722 */
723enum xenbus_state xenbus_read_driver_state(const char *path)
724{
725 enum xenbus_state result;
726 int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL);
727 if (err)
728 result = XenbusStateUnknown;
729
730 return result;
731}
732EXPORT_SYMBOL_GPL(xenbus_read_driver_state);
733
734static const struct xenbus_ring_ops ring_ops_pv = {
735 .map = xenbus_map_ring_valloc_pv,
736 .unmap = xenbus_unmap_ring_vfree_pv,
737};
738
739static const struct xenbus_ring_ops ring_ops_hvm = {
740 .map = xenbus_map_ring_valloc_hvm,
741 .unmap = xenbus_unmap_ring_vfree_hvm,
742};
743
744void __init xenbus_ring_ops_init(void)
745{
746 if (xen_pv_domain())
747 ring_ops = &ring_ops_pv;
748 else
749 ring_ops = &ring_ops_hvm;
750}
1/******************************************************************************
2 * Client-facing interface for the Xenbus driver. In other words, the
3 * interface between the Xenbus and the device-specific code, be it the
4 * frontend or the backend of that driver.
5 *
6 * Copyright (C) 2005 XenSource Ltd
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License version 2
10 * as published by the Free Software Foundation; or, when distributed
11 * separately from the Linux kernel or incorporated into other
12 * software packages, subject to the following license:
13 *
14 * Permission is hereby granted, free of charge, to any person obtaining a copy
15 * of this source file (the "Software"), to deal in the Software without
16 * restriction, including without limitation the rights to use, copy, modify,
17 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
18 * and to permit persons to whom the Software is furnished to do so, subject to
19 * the following conditions:
20 *
21 * The above copyright notice and this permission notice shall be included in
22 * all copies or substantial portions of the Software.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
29 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
30 * IN THE SOFTWARE.
31 */
32
33#include <linux/mm.h>
34#include <linux/slab.h>
35#include <linux/types.h>
36#include <linux/spinlock.h>
37#include <linux/vmalloc.h>
38#include <linux/export.h>
39#include <asm/xen/hypervisor.h>
40#include <xen/page.h>
41#include <xen/interface/xen.h>
42#include <xen/interface/event_channel.h>
43#include <xen/balloon.h>
44#include <xen/events.h>
45#include <xen/grant_table.h>
46#include <xen/xenbus.h>
47#include <xen/xen.h>
48#include <xen/features.h>
49
50#include "xenbus.h"
51
52#define XENBUS_PAGES(_grants) (DIV_ROUND_UP(_grants, XEN_PFN_PER_PAGE))
53
54#define XENBUS_MAX_RING_PAGES (XENBUS_PAGES(XENBUS_MAX_RING_GRANTS))
55
56struct xenbus_map_node {
57 struct list_head next;
58 union {
59 struct {
60 struct vm_struct *area;
61 } pv;
62 struct {
63 struct page *pages[XENBUS_MAX_RING_PAGES];
64 unsigned long addrs[XENBUS_MAX_RING_GRANTS];
65 void *addr;
66 } hvm;
67 };
68 grant_handle_t handles[XENBUS_MAX_RING_GRANTS];
69 unsigned int nr_handles;
70};
71
72struct map_ring_valloc {
73 struct xenbus_map_node *node;
74
75 /* Why do we need two arrays? See comment of __xenbus_map_ring */
76 unsigned long addrs[XENBUS_MAX_RING_GRANTS];
77 phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
78
79 struct gnttab_map_grant_ref map[XENBUS_MAX_RING_GRANTS];
80 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
81
82 unsigned int idx;
83};
84
85static DEFINE_SPINLOCK(xenbus_valloc_lock);
86static LIST_HEAD(xenbus_valloc_pages);
87
88struct xenbus_ring_ops {
89 int (*map)(struct xenbus_device *dev, struct map_ring_valloc *info,
90 grant_ref_t *gnt_refs, unsigned int nr_grefs,
91 void **vaddr);
92 int (*unmap)(struct xenbus_device *dev, void *vaddr);
93};
94
95static const struct xenbus_ring_ops *ring_ops __read_mostly;
96
97const char *xenbus_strstate(enum xenbus_state state)
98{
99 static const char *const name[] = {
100 [ XenbusStateUnknown ] = "Unknown",
101 [ XenbusStateInitialising ] = "Initialising",
102 [ XenbusStateInitWait ] = "InitWait",
103 [ XenbusStateInitialised ] = "Initialised",
104 [ XenbusStateConnected ] = "Connected",
105 [ XenbusStateClosing ] = "Closing",
106 [ XenbusStateClosed ] = "Closed",
107 [XenbusStateReconfiguring] = "Reconfiguring",
108 [XenbusStateReconfigured] = "Reconfigured",
109 };
110 return (state < ARRAY_SIZE(name)) ? name[state] : "INVALID";
111}
112EXPORT_SYMBOL_GPL(xenbus_strstate);
113
114/**
115 * xenbus_watch_path - register a watch
116 * @dev: xenbus device
117 * @path: path to watch
118 * @watch: watch to register
119 * @callback: callback to register
120 *
121 * Register a @watch on the given path, using the given xenbus_watch structure
122 * for storage, and the given @callback function as the callback. Return 0 on
123 * success, or -errno on error. On success, the given @path will be saved as
124 * @watch->node, and remains the caller's to free. On error, @watch->node will
125 * be NULL, the device will switch to %XenbusStateClosing, and the error will
126 * be saved in the store.
127 */
128int xenbus_watch_path(struct xenbus_device *dev, const char *path,
129 struct xenbus_watch *watch,
130 bool (*will_handle)(struct xenbus_watch *,
131 const char *, const char *),
132 void (*callback)(struct xenbus_watch *,
133 const char *, const char *))
134{
135 int err;
136
137 watch->node = path;
138 watch->will_handle = will_handle;
139 watch->callback = callback;
140
141 err = register_xenbus_watch(watch);
142
143 if (err) {
144 watch->node = NULL;
145 watch->will_handle = NULL;
146 watch->callback = NULL;
147 xenbus_dev_fatal(dev, err, "adding watch on %s", path);
148 }
149
150 return err;
151}
152EXPORT_SYMBOL_GPL(xenbus_watch_path);
153
154
155/**
156 * xenbus_watch_pathfmt - register a watch on a sprintf-formatted path
157 * @dev: xenbus device
158 * @watch: watch to register
159 * @callback: callback to register
160 * @pathfmt: format of path to watch
161 *
162 * Register a watch on the given @path, using the given xenbus_watch
163 * structure for storage, and the given @callback function as the callback.
164 * Return 0 on success, or -errno on error. On success, the watched path
165 * (@path/@path2) will be saved as @watch->node, and becomes the caller's to
166 * kfree(). On error, watch->node will be NULL, so the caller has nothing to
167 * free, the device will switch to %XenbusStateClosing, and the error will be
168 * saved in the store.
169 */
170int xenbus_watch_pathfmt(struct xenbus_device *dev,
171 struct xenbus_watch *watch,
172 bool (*will_handle)(struct xenbus_watch *,
173 const char *, const char *),
174 void (*callback)(struct xenbus_watch *,
175 const char *, const char *),
176 const char *pathfmt, ...)
177{
178 int err;
179 va_list ap;
180 char *path;
181
182 va_start(ap, pathfmt);
183 path = kvasprintf(GFP_NOIO | __GFP_HIGH, pathfmt, ap);
184 va_end(ap);
185
186 if (!path) {
187 xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch");
188 return -ENOMEM;
189 }
190 err = xenbus_watch_path(dev, path, watch, will_handle, callback);
191
192 if (err)
193 kfree(path);
194 return err;
195}
196EXPORT_SYMBOL_GPL(xenbus_watch_pathfmt);
197
198static void xenbus_switch_fatal(struct xenbus_device *, int, int,
199 const char *, ...);
200
201static int
202__xenbus_switch_state(struct xenbus_device *dev,
203 enum xenbus_state state, int depth)
204{
205 /* We check whether the state is currently set to the given value, and
206 if not, then the state is set. We don't want to unconditionally
207 write the given state, because we don't want to fire watches
208 unnecessarily. Furthermore, if the node has gone, we don't write
209 to it, as the device will be tearing down, and we don't want to
210 resurrect that directory.
211
212 Note that, because of this cached value of our state, this
213 function will not take a caller's Xenstore transaction
214 (something it was trying to in the past) because dev->state
215 would not get reset if the transaction was aborted.
216 */
217
218 struct xenbus_transaction xbt;
219 int current_state;
220 int err, abort;
221
222 if (state == dev->state)
223 return 0;
224
225again:
226 abort = 1;
227
228 err = xenbus_transaction_start(&xbt);
229 if (err) {
230 xenbus_switch_fatal(dev, depth, err, "starting transaction");
231 return 0;
232 }
233
234 err = xenbus_scanf(xbt, dev->nodename, "state", "%d", ¤t_state);
235 if (err != 1)
236 goto abort;
237
238 err = xenbus_printf(xbt, dev->nodename, "state", "%d", state);
239 if (err) {
240 xenbus_switch_fatal(dev, depth, err, "writing new state");
241 goto abort;
242 }
243
244 abort = 0;
245abort:
246 err = xenbus_transaction_end(xbt, abort);
247 if (err) {
248 if (err == -EAGAIN && !abort)
249 goto again;
250 xenbus_switch_fatal(dev, depth, err, "ending transaction");
251 } else
252 dev->state = state;
253
254 return 0;
255}
256
257/**
258 * xenbus_switch_state
259 * @dev: xenbus device
260 * @state: new state
261 *
262 * Advertise in the store a change of the given driver to the given new_state.
263 * Return 0 on success, or -errno on error. On error, the device will switch
264 * to XenbusStateClosing, and the error will be saved in the store.
265 */
266int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state)
267{
268 return __xenbus_switch_state(dev, state, 0);
269}
270
271EXPORT_SYMBOL_GPL(xenbus_switch_state);
272
273int xenbus_frontend_closed(struct xenbus_device *dev)
274{
275 xenbus_switch_state(dev, XenbusStateClosed);
276 complete(&dev->down);
277 return 0;
278}
279EXPORT_SYMBOL_GPL(xenbus_frontend_closed);
280
281static void xenbus_va_dev_error(struct xenbus_device *dev, int err,
282 const char *fmt, va_list ap)
283{
284 unsigned int len;
285 char *printf_buffer;
286 char *path_buffer;
287
288#define PRINTF_BUFFER_SIZE 4096
289
290 printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL);
291 if (!printf_buffer)
292 return;
293
294 len = sprintf(printf_buffer, "%i ", -err);
295 vsnprintf(printf_buffer + len, PRINTF_BUFFER_SIZE - len, fmt, ap);
296
297 dev_err(&dev->dev, "%s\n", printf_buffer);
298
299 path_buffer = kasprintf(GFP_KERNEL, "error/%s", dev->nodename);
300 if (path_buffer)
301 xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer);
302
303 kfree(printf_buffer);
304 kfree(path_buffer);
305}
306
307/**
308 * xenbus_dev_error
309 * @dev: xenbus device
310 * @err: error to report
311 * @fmt: error message format
312 *
313 * Report the given negative errno into the store, along with the given
314 * formatted message.
315 */
316void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...)
317{
318 va_list ap;
319
320 va_start(ap, fmt);
321 xenbus_va_dev_error(dev, err, fmt, ap);
322 va_end(ap);
323}
324EXPORT_SYMBOL_GPL(xenbus_dev_error);
325
326/**
327 * xenbus_dev_fatal
328 * @dev: xenbus device
329 * @err: error to report
330 * @fmt: error message format
331 *
332 * Equivalent to xenbus_dev_error(dev, err, fmt, args), followed by
333 * xenbus_switch_state(dev, XenbusStateClosing) to schedule an orderly
334 * closedown of this driver and its peer.
335 */
336
337void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...)
338{
339 va_list ap;
340
341 va_start(ap, fmt);
342 xenbus_va_dev_error(dev, err, fmt, ap);
343 va_end(ap);
344
345 xenbus_switch_state(dev, XenbusStateClosing);
346}
347EXPORT_SYMBOL_GPL(xenbus_dev_fatal);
348
349/**
350 * Equivalent to xenbus_dev_fatal(dev, err, fmt, args), but helps
351 * avoiding recursion within xenbus_switch_state.
352 */
353static void xenbus_switch_fatal(struct xenbus_device *dev, int depth, int err,
354 const char *fmt, ...)
355{
356 va_list ap;
357
358 va_start(ap, fmt);
359 xenbus_va_dev_error(dev, err, fmt, ap);
360 va_end(ap);
361
362 if (!depth)
363 __xenbus_switch_state(dev, XenbusStateClosing, 1);
364}
365
366/*
367 * xenbus_setup_ring
368 * @dev: xenbus device
369 * @vaddr: pointer to starting virtual address of the ring
370 * @nr_pages: number of pages to be granted
371 * @grefs: grant reference array to be filled in
372 *
373 * Allocate physically contiguous pages for a shared ring buffer and grant it
374 * to the peer of the given device. The ring buffer is initially filled with
375 * zeroes. The virtual address of the ring is stored at @vaddr and the
376 * grant references are stored in the @grefs array. In case of error @vaddr
377 * will be set to NULL and @grefs will be filled with INVALID_GRANT_REF.
378 */
379int xenbus_setup_ring(struct xenbus_device *dev, gfp_t gfp, void **vaddr,
380 unsigned int nr_pages, grant_ref_t *grefs)
381{
382 unsigned long ring_size = nr_pages * XEN_PAGE_SIZE;
383 grant_ref_t gref_head;
384 unsigned int i;
385 void *addr;
386 int ret;
387
388 addr = *vaddr = alloc_pages_exact(ring_size, gfp | __GFP_ZERO);
389 if (!*vaddr) {
390 ret = -ENOMEM;
391 goto err;
392 }
393
394 ret = gnttab_alloc_grant_references(nr_pages, &gref_head);
395 if (ret) {
396 xenbus_dev_fatal(dev, ret, "granting access to %u ring pages",
397 nr_pages);
398 goto err;
399 }
400
401 for (i = 0; i < nr_pages; i++) {
402 unsigned long gfn;
403
404 if (is_vmalloc_addr(*vaddr))
405 gfn = pfn_to_gfn(vmalloc_to_pfn(addr));
406 else
407 gfn = virt_to_gfn(addr);
408
409 grefs[i] = gnttab_claim_grant_reference(&gref_head);
410 gnttab_grant_foreign_access_ref(grefs[i], dev->otherend_id,
411 gfn, 0);
412
413 addr += XEN_PAGE_SIZE;
414 }
415
416 return 0;
417
418 err:
419 if (*vaddr)
420 free_pages_exact(*vaddr, ring_size);
421 for (i = 0; i < nr_pages; i++)
422 grefs[i] = INVALID_GRANT_REF;
423 *vaddr = NULL;
424
425 return ret;
426}
427EXPORT_SYMBOL_GPL(xenbus_setup_ring);
428
429/*
430 * xenbus_teardown_ring
431 * @vaddr: starting virtual address of the ring
432 * @nr_pages: number of pages
433 * @grefs: grant reference array
434 *
435 * Remove grants for the shared ring buffer and free the associated memory.
436 * On return the grant reference array is filled with INVALID_GRANT_REF.
437 */
438void xenbus_teardown_ring(void **vaddr, unsigned int nr_pages,
439 grant_ref_t *grefs)
440{
441 unsigned int i;
442
443 for (i = 0; i < nr_pages; i++) {
444 if (grefs[i] != INVALID_GRANT_REF) {
445 gnttab_end_foreign_access(grefs[i], NULL);
446 grefs[i] = INVALID_GRANT_REF;
447 }
448 }
449
450 if (*vaddr)
451 free_pages_exact(*vaddr, nr_pages * XEN_PAGE_SIZE);
452 *vaddr = NULL;
453}
454EXPORT_SYMBOL_GPL(xenbus_teardown_ring);
455
456/**
457 * Allocate an event channel for the given xenbus_device, assigning the newly
458 * created local port to *port. Return 0 on success, or -errno on error. On
459 * error, the device will switch to XenbusStateClosing, and the error will be
460 * saved in the store.
461 */
462int xenbus_alloc_evtchn(struct xenbus_device *dev, evtchn_port_t *port)
463{
464 struct evtchn_alloc_unbound alloc_unbound;
465 int err;
466
467 alloc_unbound.dom = DOMID_SELF;
468 alloc_unbound.remote_dom = dev->otherend_id;
469
470 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
471 &alloc_unbound);
472 if (err)
473 xenbus_dev_fatal(dev, err, "allocating event channel");
474 else
475 *port = alloc_unbound.port;
476
477 return err;
478}
479EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn);
480
481
482/**
483 * Free an existing event channel. Returns 0 on success or -errno on error.
484 */
485int xenbus_free_evtchn(struct xenbus_device *dev, evtchn_port_t port)
486{
487 struct evtchn_close close;
488 int err;
489
490 close.port = port;
491
492 err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
493 if (err)
494 xenbus_dev_error(dev, err, "freeing event channel %u", port);
495
496 return err;
497}
498EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
499
500
501/**
502 * xenbus_map_ring_valloc
503 * @dev: xenbus device
504 * @gnt_refs: grant reference array
505 * @nr_grefs: number of grant references
506 * @vaddr: pointer to address to be filled out by mapping
507 *
508 * Map @nr_grefs pages of memory into this domain from another
509 * domain's grant table. xenbus_map_ring_valloc allocates @nr_grefs
510 * pages of virtual address space, maps the pages to that address, and
511 * sets *vaddr to that address. Returns 0 on success, and -errno on
512 * error. If an error is returned, device will switch to
513 * XenbusStateClosing and the error message will be saved in XenStore.
514 */
515int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
516 unsigned int nr_grefs, void **vaddr)
517{
518 int err;
519 struct map_ring_valloc *info;
520
521 *vaddr = NULL;
522
523 if (nr_grefs > XENBUS_MAX_RING_GRANTS)
524 return -EINVAL;
525
526 info = kzalloc(sizeof(*info), GFP_KERNEL);
527 if (!info)
528 return -ENOMEM;
529
530 info->node = kzalloc(sizeof(*info->node), GFP_KERNEL);
531 if (!info->node)
532 err = -ENOMEM;
533 else
534 err = ring_ops->map(dev, info, gnt_refs, nr_grefs, vaddr);
535
536 kfree(info->node);
537 kfree(info);
538 return err;
539}
540EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);
541
542/* N.B. sizeof(phys_addr_t) doesn't always equal to sizeof(unsigned
543 * long), e.g. 32-on-64. Caller is responsible for preparing the
544 * right array to feed into this function */
545static int __xenbus_map_ring(struct xenbus_device *dev,
546 grant_ref_t *gnt_refs,
547 unsigned int nr_grefs,
548 grant_handle_t *handles,
549 struct map_ring_valloc *info,
550 unsigned int flags,
551 bool *leaked)
552{
553 int i, j;
554
555 if (nr_grefs > XENBUS_MAX_RING_GRANTS)
556 return -EINVAL;
557
558 for (i = 0; i < nr_grefs; i++) {
559 gnttab_set_map_op(&info->map[i], info->phys_addrs[i], flags,
560 gnt_refs[i], dev->otherend_id);
561 handles[i] = INVALID_GRANT_HANDLE;
562 }
563
564 gnttab_batch_map(info->map, i);
565
566 for (i = 0; i < nr_grefs; i++) {
567 if (info->map[i].status != GNTST_okay) {
568 xenbus_dev_fatal(dev, info->map[i].status,
569 "mapping in shared page %d from domain %d",
570 gnt_refs[i], dev->otherend_id);
571 goto fail;
572 } else
573 handles[i] = info->map[i].handle;
574 }
575
576 return 0;
577
578 fail:
579 for (i = j = 0; i < nr_grefs; i++) {
580 if (handles[i] != INVALID_GRANT_HANDLE) {
581 gnttab_set_unmap_op(&info->unmap[j],
582 info->phys_addrs[i],
583 GNTMAP_host_map, handles[i]);
584 j++;
585 }
586 }
587
588 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, info->unmap, j));
589
590 *leaked = false;
591 for (i = 0; i < j; i++) {
592 if (info->unmap[i].status != GNTST_okay) {
593 *leaked = true;
594 break;
595 }
596 }
597
598 return -ENOENT;
599}
600
601/**
602 * xenbus_unmap_ring
603 * @dev: xenbus device
604 * @handles: grant handle array
605 * @nr_handles: number of handles in the array
606 * @vaddrs: addresses to unmap
607 *
608 * Unmap memory in this domain that was imported from another domain.
609 * Returns 0 on success and returns GNTST_* on error
610 * (see xen/include/interface/grant_table.h).
611 */
612static int xenbus_unmap_ring(struct xenbus_device *dev, grant_handle_t *handles,
613 unsigned int nr_handles, unsigned long *vaddrs)
614{
615 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
616 int i;
617 int err;
618
619 if (nr_handles > XENBUS_MAX_RING_GRANTS)
620 return -EINVAL;
621
622 for (i = 0; i < nr_handles; i++)
623 gnttab_set_unmap_op(&unmap[i], vaddrs[i],
624 GNTMAP_host_map, handles[i]);
625
626 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i));
627
628 err = GNTST_okay;
629 for (i = 0; i < nr_handles; i++) {
630 if (unmap[i].status != GNTST_okay) {
631 xenbus_dev_error(dev, unmap[i].status,
632 "unmapping page at handle %d error %d",
633 handles[i], unmap[i].status);
634 err = unmap[i].status;
635 break;
636 }
637 }
638
639 return err;
640}
641
642static void xenbus_map_ring_setup_grant_hvm(unsigned long gfn,
643 unsigned int goffset,
644 unsigned int len,
645 void *data)
646{
647 struct map_ring_valloc *info = data;
648 unsigned long vaddr = (unsigned long)gfn_to_virt(gfn);
649
650 info->phys_addrs[info->idx] = vaddr;
651 info->addrs[info->idx] = vaddr;
652
653 info->idx++;
654}
655
656static int xenbus_map_ring_hvm(struct xenbus_device *dev,
657 struct map_ring_valloc *info,
658 grant_ref_t *gnt_ref,
659 unsigned int nr_grefs,
660 void **vaddr)
661{
662 struct xenbus_map_node *node = info->node;
663 int err;
664 void *addr;
665 bool leaked = false;
666 unsigned int nr_pages = XENBUS_PAGES(nr_grefs);
667
668 err = xen_alloc_unpopulated_pages(nr_pages, node->hvm.pages);
669 if (err)
670 goto out_err;
671
672 gnttab_foreach_grant(node->hvm.pages, nr_grefs,
673 xenbus_map_ring_setup_grant_hvm,
674 info);
675
676 err = __xenbus_map_ring(dev, gnt_ref, nr_grefs, node->handles,
677 info, GNTMAP_host_map, &leaked);
678 node->nr_handles = nr_grefs;
679
680 if (err)
681 goto out_free_ballooned_pages;
682
683 addr = vmap(node->hvm.pages, nr_pages, VM_MAP | VM_IOREMAP,
684 PAGE_KERNEL);
685 if (!addr) {
686 err = -ENOMEM;
687 goto out_xenbus_unmap_ring;
688 }
689
690 node->hvm.addr = addr;
691
692 spin_lock(&xenbus_valloc_lock);
693 list_add(&node->next, &xenbus_valloc_pages);
694 spin_unlock(&xenbus_valloc_lock);
695
696 *vaddr = addr;
697 info->node = NULL;
698
699 return 0;
700
701 out_xenbus_unmap_ring:
702 if (!leaked)
703 xenbus_unmap_ring(dev, node->handles, nr_grefs, info->addrs);
704 else
705 pr_alert("leaking %p size %u page(s)",
706 addr, nr_pages);
707 out_free_ballooned_pages:
708 if (!leaked)
709 xen_free_unpopulated_pages(nr_pages, node->hvm.pages);
710 out_err:
711 return err;
712}
713
714/**
715 * xenbus_unmap_ring_vfree
716 * @dev: xenbus device
717 * @vaddr: addr to unmap
718 *
719 * Based on Rusty Russell's skeleton driver's unmap_page.
720 * Unmap a page of memory in this domain that was imported from another domain.
721 * Use xenbus_unmap_ring_vfree if you mapped in your memory with
722 * xenbus_map_ring_valloc (it will free the virtual address space).
723 * Returns 0 on success and returns GNTST_* on error
724 * (see xen/include/interface/grant_table.h).
725 */
726int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
727{
728 return ring_ops->unmap(dev, vaddr);
729}
730EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree);
731
732#ifdef CONFIG_XEN_PV
733static int map_ring_apply(pte_t *pte, unsigned long addr, void *data)
734{
735 struct map_ring_valloc *info = data;
736
737 info->phys_addrs[info->idx++] = arbitrary_virt_to_machine(pte).maddr;
738 return 0;
739}
740
741static int xenbus_map_ring_pv(struct xenbus_device *dev,
742 struct map_ring_valloc *info,
743 grant_ref_t *gnt_refs,
744 unsigned int nr_grefs,
745 void **vaddr)
746{
747 struct xenbus_map_node *node = info->node;
748 struct vm_struct *area;
749 bool leaked = false;
750 int err = -ENOMEM;
751
752 area = get_vm_area(XEN_PAGE_SIZE * nr_grefs, VM_IOREMAP);
753 if (!area)
754 return -ENOMEM;
755 if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
756 XEN_PAGE_SIZE * nr_grefs, map_ring_apply, info))
757 goto failed;
758 err = __xenbus_map_ring(dev, gnt_refs, nr_grefs, node->handles,
759 info, GNTMAP_host_map | GNTMAP_contains_pte,
760 &leaked);
761 if (err)
762 goto failed;
763
764 node->nr_handles = nr_grefs;
765 node->pv.area = area;
766
767 spin_lock(&xenbus_valloc_lock);
768 list_add(&node->next, &xenbus_valloc_pages);
769 spin_unlock(&xenbus_valloc_lock);
770
771 *vaddr = area->addr;
772 info->node = NULL;
773
774 return 0;
775
776failed:
777 if (!leaked)
778 free_vm_area(area);
779 else
780 pr_alert("leaking VM area %p size %u page(s)", area, nr_grefs);
781
782 return err;
783}
784
785static int xenbus_unmap_ring_pv(struct xenbus_device *dev, void *vaddr)
786{
787 struct xenbus_map_node *node;
788 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
789 unsigned int level;
790 int i;
791 bool leaked = false;
792 int err;
793
794 spin_lock(&xenbus_valloc_lock);
795 list_for_each_entry(node, &xenbus_valloc_pages, next) {
796 if (node->pv.area->addr == vaddr) {
797 list_del(&node->next);
798 goto found;
799 }
800 }
801 node = NULL;
802 found:
803 spin_unlock(&xenbus_valloc_lock);
804
805 if (!node) {
806 xenbus_dev_error(dev, -ENOENT,
807 "can't find mapped virtual address %p", vaddr);
808 return GNTST_bad_virt_addr;
809 }
810
811 for (i = 0; i < node->nr_handles; i++) {
812 unsigned long addr;
813
814 memset(&unmap[i], 0, sizeof(unmap[i]));
815 addr = (unsigned long)vaddr + (XEN_PAGE_SIZE * i);
816 unmap[i].host_addr = arbitrary_virt_to_machine(
817 lookup_address(addr, &level)).maddr;
818 unmap[i].dev_bus_addr = 0;
819 unmap[i].handle = node->handles[i];
820 }
821
822 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i));
823
824 err = GNTST_okay;
825 leaked = false;
826 for (i = 0; i < node->nr_handles; i++) {
827 if (unmap[i].status != GNTST_okay) {
828 leaked = true;
829 xenbus_dev_error(dev, unmap[i].status,
830 "unmapping page at handle %d error %d",
831 node->handles[i], unmap[i].status);
832 err = unmap[i].status;
833 break;
834 }
835 }
836
837 if (!leaked)
838 free_vm_area(node->pv.area);
839 else
840 pr_alert("leaking VM area %p size %u page(s)",
841 node->pv.area, node->nr_handles);
842
843 kfree(node);
844 return err;
845}
846
847static const struct xenbus_ring_ops ring_ops_pv = {
848 .map = xenbus_map_ring_pv,
849 .unmap = xenbus_unmap_ring_pv,
850};
851#endif
852
853struct unmap_ring_hvm
854{
855 unsigned int idx;
856 unsigned long addrs[XENBUS_MAX_RING_GRANTS];
857};
858
859static void xenbus_unmap_ring_setup_grant_hvm(unsigned long gfn,
860 unsigned int goffset,
861 unsigned int len,
862 void *data)
863{
864 struct unmap_ring_hvm *info = data;
865
866 info->addrs[info->idx] = (unsigned long)gfn_to_virt(gfn);
867
868 info->idx++;
869}
870
871static int xenbus_unmap_ring_hvm(struct xenbus_device *dev, void *vaddr)
872{
873 int rv;
874 struct xenbus_map_node *node;
875 void *addr;
876 struct unmap_ring_hvm info = {
877 .idx = 0,
878 };
879 unsigned int nr_pages;
880
881 spin_lock(&xenbus_valloc_lock);
882 list_for_each_entry(node, &xenbus_valloc_pages, next) {
883 addr = node->hvm.addr;
884 if (addr == vaddr) {
885 list_del(&node->next);
886 goto found;
887 }
888 }
889 node = addr = NULL;
890 found:
891 spin_unlock(&xenbus_valloc_lock);
892
893 if (!node) {
894 xenbus_dev_error(dev, -ENOENT,
895 "can't find mapped virtual address %p", vaddr);
896 return GNTST_bad_virt_addr;
897 }
898
899 nr_pages = XENBUS_PAGES(node->nr_handles);
900
901 gnttab_foreach_grant(node->hvm.pages, node->nr_handles,
902 xenbus_unmap_ring_setup_grant_hvm,
903 &info);
904
905 rv = xenbus_unmap_ring(dev, node->handles, node->nr_handles,
906 info.addrs);
907 if (!rv) {
908 vunmap(vaddr);
909 xen_free_unpopulated_pages(nr_pages, node->hvm.pages);
910 }
911 else
912 WARN(1, "Leaking %p, size %u page(s)\n", vaddr, nr_pages);
913
914 kfree(node);
915 return rv;
916}
917
918/**
919 * xenbus_read_driver_state
920 * @path: path for driver
921 *
922 * Return the state of the driver rooted at the given store path, or
923 * XenbusStateUnknown if no state can be read.
924 */
925enum xenbus_state xenbus_read_driver_state(const char *path)
926{
927 enum xenbus_state result;
928 int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL);
929 if (err)
930 result = XenbusStateUnknown;
931
932 return result;
933}
934EXPORT_SYMBOL_GPL(xenbus_read_driver_state);
935
936static const struct xenbus_ring_ops ring_ops_hvm = {
937 .map = xenbus_map_ring_hvm,
938 .unmap = xenbus_unmap_ring_hvm,
939};
940
941void __init xenbus_ring_ops_init(void)
942{
943#ifdef CONFIG_XEN_PV
944 if (!xen_feature(XENFEAT_auto_translated_physmap))
945 ring_ops = &ring_ops_pv;
946 else
947#endif
948 ring_ops = &ring_ops_hvm;
949}