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.
6 * Copyright (C) 2005 XenSource Ltd
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:
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:
21 * The above copyright notice and this permission notice shall be included in
22 * all copies or substantial portions of the Software.
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
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>
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>
48 #include <xen/features.h>
52 #define XENBUS_PAGES(_grants) (DIV_ROUND_UP(_grants, XEN_PFN_PER_PAGE))
54 #define XENBUS_MAX_RING_PAGES (XENBUS_PAGES(XENBUS_MAX_RING_GRANTS))
56 struct xenbus_map_node {
57 struct list_head next;
60 struct vm_struct *area;
63 struct page *pages[XENBUS_MAX_RING_PAGES];
64 unsigned long addrs[XENBUS_MAX_RING_GRANTS];
68 grant_handle_t handles[XENBUS_MAX_RING_GRANTS];
69 unsigned int nr_handles;
72 static DEFINE_SPINLOCK(xenbus_valloc_lock);
73 static LIST_HEAD(xenbus_valloc_pages);
75 struct xenbus_ring_ops {
76 int (*map)(struct xenbus_device *dev,
77 grant_ref_t *gnt_refs, unsigned int nr_grefs,
79 int (*unmap)(struct xenbus_device *dev, void *vaddr);
82 static const struct xenbus_ring_ops *ring_ops __read_mostly;
84 const char *xenbus_strstate(enum xenbus_state state)
86 static const char *const name[] = {
87 [ XenbusStateUnknown ] = "Unknown",
88 [ XenbusStateInitialising ] = "Initialising",
89 [ XenbusStateInitWait ] = "InitWait",
90 [ XenbusStateInitialised ] = "Initialised",
91 [ XenbusStateConnected ] = "Connected",
92 [ XenbusStateClosing ] = "Closing",
93 [ XenbusStateClosed ] = "Closed",
94 [XenbusStateReconfiguring] = "Reconfiguring",
95 [XenbusStateReconfigured] = "Reconfigured",
97 return (state < ARRAY_SIZE(name)) ? name[state] : "INVALID";
99 EXPORT_SYMBOL_GPL(xenbus_strstate);
102 * xenbus_watch_path - register a watch
103 * @dev: xenbus device
104 * @path: path to watch
105 * @watch: watch to register
106 * @callback: callback to register
108 * Register a @watch on the given path, using the given xenbus_watch structure
109 * for storage, and the given @callback function as the callback. Return 0 on
110 * success, or -errno on error. On success, the given @path will be saved as
111 * @watch->node, and remains the caller's to free. On error, @watch->node will
112 * be NULL, the device will switch to %XenbusStateClosing, and the error will
113 * be saved in the store.
115 int xenbus_watch_path(struct xenbus_device *dev, const char *path,
116 struct xenbus_watch *watch,
117 void (*callback)(struct xenbus_watch *,
118 const char *, const char *))
123 watch->callback = callback;
125 err = register_xenbus_watch(watch);
129 watch->callback = NULL;
130 xenbus_dev_fatal(dev, err, "adding watch on %s", path);
135 EXPORT_SYMBOL_GPL(xenbus_watch_path);
139 * xenbus_watch_pathfmt - register a watch on a sprintf-formatted path
140 * @dev: xenbus device
141 * @watch: watch to register
142 * @callback: callback to register
143 * @pathfmt: format of path to watch
145 * Register a watch on the given @path, using the given xenbus_watch
146 * structure for storage, and the given @callback function as the callback.
147 * Return 0 on success, or -errno on error. On success, the watched path
148 * (@path/@path2) will be saved as @watch->node, and becomes the caller's to
149 * kfree(). On error, watch->node will be NULL, so the caller has nothing to
150 * free, the device will switch to %XenbusStateClosing, and the error will be
151 * saved in the store.
153 int xenbus_watch_pathfmt(struct xenbus_device *dev,
154 struct xenbus_watch *watch,
155 void (*callback)(struct xenbus_watch *,
156 const char *, const char *),
157 const char *pathfmt, ...)
163 va_start(ap, pathfmt);
164 path = kvasprintf(GFP_NOIO | __GFP_HIGH, pathfmt, ap);
168 xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch");
171 err = xenbus_watch_path(dev, path, watch, callback);
177 EXPORT_SYMBOL_GPL(xenbus_watch_pathfmt);
179 static void xenbus_switch_fatal(struct xenbus_device *, int, int,
183 __xenbus_switch_state(struct xenbus_device *dev,
184 enum xenbus_state state, int depth)
186 /* We check whether the state is currently set to the given value, and
187 if not, then the state is set. We don't want to unconditionally
188 write the given state, because we don't want to fire watches
189 unnecessarily. Furthermore, if the node has gone, we don't write
190 to it, as the device will be tearing down, and we don't want to
191 resurrect that directory.
193 Note that, because of this cached value of our state, this
194 function will not take a caller's Xenstore transaction
195 (something it was trying to in the past) because dev->state
196 would not get reset if the transaction was aborted.
199 struct xenbus_transaction xbt;
203 if (state == dev->state)
209 err = xenbus_transaction_start(&xbt);
211 xenbus_switch_fatal(dev, depth, err, "starting transaction");
215 err = xenbus_scanf(xbt, dev->nodename, "state", "%d", ¤t_state);
219 err = xenbus_printf(xbt, dev->nodename, "state", "%d", state);
221 xenbus_switch_fatal(dev, depth, err, "writing new state");
227 err = xenbus_transaction_end(xbt, abort);
229 if (err == -EAGAIN && !abort)
231 xenbus_switch_fatal(dev, depth, err, "ending transaction");
239 * xenbus_switch_state
240 * @dev: xenbus device
243 * Advertise in the store a change of the given driver to the given new_state.
244 * Return 0 on success, or -errno on error. On error, the device will switch
245 * to XenbusStateClosing, and the error will be saved in the store.
247 int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state)
249 return __xenbus_switch_state(dev, state, 0);
252 EXPORT_SYMBOL_GPL(xenbus_switch_state);
254 int xenbus_frontend_closed(struct xenbus_device *dev)
256 xenbus_switch_state(dev, XenbusStateClosed);
257 complete(&dev->down);
260 EXPORT_SYMBOL_GPL(xenbus_frontend_closed);
262 static void xenbus_va_dev_error(struct xenbus_device *dev, int err,
263 const char *fmt, va_list ap)
269 #define PRINTF_BUFFER_SIZE 4096
271 printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL);
275 len = sprintf(printf_buffer, "%i ", -err);
276 vsnprintf(printf_buffer + len, PRINTF_BUFFER_SIZE - len, fmt, ap);
278 dev_err(&dev->dev, "%s\n", printf_buffer);
280 path_buffer = kasprintf(GFP_KERNEL, "error/%s", dev->nodename);
282 xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer))
283 dev_err(&dev->dev, "failed to write error node for %s (%s)\n",
284 dev->nodename, printf_buffer);
286 kfree(printf_buffer);
292 * @dev: xenbus device
293 * @err: error to report
294 * @fmt: error message format
296 * Report the given negative errno into the store, along with the given
299 void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...)
304 xenbus_va_dev_error(dev, err, fmt, ap);
307 EXPORT_SYMBOL_GPL(xenbus_dev_error);
311 * @dev: xenbus device
312 * @err: error to report
313 * @fmt: error message format
315 * Equivalent to xenbus_dev_error(dev, err, fmt, args), followed by
316 * xenbus_switch_state(dev, XenbusStateClosing) to schedule an orderly
317 * closedown of this driver and its peer.
320 void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...)
325 xenbus_va_dev_error(dev, err, fmt, ap);
328 xenbus_switch_state(dev, XenbusStateClosing);
330 EXPORT_SYMBOL_GPL(xenbus_dev_fatal);
333 * Equivalent to xenbus_dev_fatal(dev, err, fmt, args), but helps
334 * avoiding recursion within xenbus_switch_state.
336 static void xenbus_switch_fatal(struct xenbus_device *dev, int depth, int err,
337 const char *fmt, ...)
342 xenbus_va_dev_error(dev, err, fmt, ap);
346 __xenbus_switch_state(dev, XenbusStateClosing, 1);
351 * @dev: xenbus device
352 * @vaddr: starting virtual address of the ring
353 * @nr_pages: number of pages to be granted
354 * @grefs: grant reference array to be filled in
356 * Grant access to the given @vaddr to the peer of the given device.
357 * Then fill in @grefs with grant references. Return 0 on success, or
358 * -errno on error. On error, the device will switch to
359 * XenbusStateClosing, and the error will be saved in the store.
361 int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
362 unsigned int nr_pages, grant_ref_t *grefs)
367 for (i = 0; i < nr_pages; i++) {
368 err = gnttab_grant_foreign_access(dev->otherend_id,
369 virt_to_gfn(vaddr), 0);
371 xenbus_dev_fatal(dev, err,
372 "granting access to ring page");
377 vaddr = vaddr + XEN_PAGE_SIZE;
383 for (j = 0; j < i; j++)
384 gnttab_end_foreign_access_ref(grefs[j], 0);
387 EXPORT_SYMBOL_GPL(xenbus_grant_ring);
391 * Allocate an event channel for the given xenbus_device, assigning the newly
392 * created local port to *port. Return 0 on success, or -errno on error. On
393 * error, the device will switch to XenbusStateClosing, and the error will be
394 * saved in the store.
396 int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port)
398 struct evtchn_alloc_unbound alloc_unbound;
401 alloc_unbound.dom = DOMID_SELF;
402 alloc_unbound.remote_dom = dev->otherend_id;
404 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
407 xenbus_dev_fatal(dev, err, "allocating event channel");
409 *port = alloc_unbound.port;
413 EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn);
417 * Free an existing event channel. Returns 0 on success or -errno on error.
419 int xenbus_free_evtchn(struct xenbus_device *dev, int port)
421 struct evtchn_close close;
426 err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
428 xenbus_dev_error(dev, err, "freeing event channel %d", port);
432 EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
436 * xenbus_map_ring_valloc
437 * @dev: xenbus device
438 * @gnt_refs: grant reference array
439 * @nr_grefs: number of grant references
440 * @vaddr: pointer to address to be filled out by mapping
442 * Map @nr_grefs pages of memory into this domain from another
443 * domain's grant table. xenbus_map_ring_valloc allocates @nr_grefs
444 * pages of virtual address space, maps the pages to that address, and
445 * sets *vaddr to that address. Returns 0 on success, and GNTST_*
446 * (see xen/include/interface/grant_table.h) or -ENOMEM / -EINVAL on
447 * error. If an error is returned, device will switch to
448 * XenbusStateClosing and the error message will be saved in XenStore.
450 int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
451 unsigned int nr_grefs, void **vaddr)
453 return ring_ops->map(dev, gnt_refs, nr_grefs, vaddr);
455 EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);
457 /* N.B. sizeof(phys_addr_t) doesn't always equal to sizeof(unsigned
458 * long), e.g. 32-on-64. Caller is responsible for preparing the
459 * right array to feed into this function */
460 static int __xenbus_map_ring(struct xenbus_device *dev,
461 grant_ref_t *gnt_refs,
462 unsigned int nr_grefs,
463 grant_handle_t *handles,
468 struct gnttab_map_grant_ref map[XENBUS_MAX_RING_GRANTS];
469 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
471 int err = GNTST_okay;
473 if (nr_grefs > XENBUS_MAX_RING_GRANTS)
476 for (i = 0; i < nr_grefs; i++) {
477 memset(&map[i], 0, sizeof(map[i]));
478 gnttab_set_map_op(&map[i], addrs[i], flags, gnt_refs[i],
480 handles[i] = INVALID_GRANT_HANDLE;
483 gnttab_batch_map(map, i);
485 for (i = 0; i < nr_grefs; i++) {
486 if (map[i].status != GNTST_okay) {
488 xenbus_dev_fatal(dev, map[i].status,
489 "mapping in shared page %d from domain %d",
490 gnt_refs[i], dev->otherend_id);
493 handles[i] = map[i].handle;
499 for (i = j = 0; i < nr_grefs; i++) {
500 if (handles[i] != INVALID_GRANT_HANDLE) {
501 memset(&unmap[j], 0, sizeof(unmap[j]));
502 gnttab_set_unmap_op(&unmap[j], (phys_addr_t)addrs[i],
503 GNTMAP_host_map, handles[i]);
508 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, j))
512 for (i = 0; i < j; i++) {
513 if (unmap[i].status != GNTST_okay) {
522 static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
523 grant_ref_t *gnt_refs,
524 unsigned int nr_grefs,
527 struct xenbus_map_node *node;
528 struct vm_struct *area;
529 pte_t *ptes[XENBUS_MAX_RING_GRANTS];
530 phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
531 int err = GNTST_okay;
537 if (nr_grefs > XENBUS_MAX_RING_GRANTS)
540 node = kzalloc(sizeof(*node), GFP_KERNEL);
544 area = alloc_vm_area(XEN_PAGE_SIZE * nr_grefs, ptes);
550 for (i = 0; i < nr_grefs; i++)
551 phys_addrs[i] = arbitrary_virt_to_machine(ptes[i]).maddr;
553 err = __xenbus_map_ring(dev, gnt_refs, nr_grefs, node->handles,
555 GNTMAP_host_map | GNTMAP_contains_pte,
560 node->nr_handles = nr_grefs;
561 node->pv.area = area;
563 spin_lock(&xenbus_valloc_lock);
564 list_add(&node->next, &xenbus_valloc_pages);
565 spin_unlock(&xenbus_valloc_lock);
574 pr_alert("leaking VM area %p size %u page(s)", area, nr_grefs);
580 struct map_ring_valloc_hvm
584 /* Why do we need two arrays? See comment of __xenbus_map_ring */
585 phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
586 unsigned long addrs[XENBUS_MAX_RING_GRANTS];
589 static void xenbus_map_ring_setup_grant_hvm(unsigned long gfn,
590 unsigned int goffset,
594 struct map_ring_valloc_hvm *info = data;
595 unsigned long vaddr = (unsigned long)gfn_to_virt(gfn);
597 info->phys_addrs[info->idx] = vaddr;
598 info->addrs[info->idx] = vaddr;
603 static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
604 grant_ref_t *gnt_ref,
605 unsigned int nr_grefs,
608 struct xenbus_map_node *node;
612 struct map_ring_valloc_hvm info = {
615 unsigned int nr_pages = XENBUS_PAGES(nr_grefs);
617 if (nr_grefs > XENBUS_MAX_RING_GRANTS)
622 node = kzalloc(sizeof(*node), GFP_KERNEL);
626 err = alloc_xenballooned_pages(nr_pages, node->hvm.pages);
630 gnttab_foreach_grant(node->hvm.pages, nr_grefs,
631 xenbus_map_ring_setup_grant_hvm,
634 err = __xenbus_map_ring(dev, gnt_ref, nr_grefs, node->handles,
635 info.phys_addrs, GNTMAP_host_map, &leaked);
636 node->nr_handles = nr_grefs;
639 goto out_free_ballooned_pages;
641 addr = vmap(node->hvm.pages, nr_pages, VM_MAP | VM_IOREMAP,
645 goto out_xenbus_unmap_ring;
648 node->hvm.addr = addr;
650 spin_lock(&xenbus_valloc_lock);
651 list_add(&node->next, &xenbus_valloc_pages);
652 spin_unlock(&xenbus_valloc_lock);
657 out_xenbus_unmap_ring:
659 xenbus_unmap_ring(dev, node->handles, nr_grefs, info.addrs);
661 pr_alert("leaking %p size %u page(s)",
663 out_free_ballooned_pages:
665 free_xenballooned_pages(nr_pages, node->hvm.pages);
674 * @dev: xenbus device
675 * @gnt_refs: grant reference array
676 * @nr_grefs: number of grant reference
677 * @handles: pointer to grant handle to be filled
678 * @vaddrs: addresses to be mapped to
679 * @leaked: fail to clean up a failed map, caller should not free vaddr
681 * Map pages of memory into this domain from another domain's grant table.
682 * xenbus_map_ring does not allocate the virtual address space (you must do
683 * this yourself!). It only maps in the pages to the specified address.
684 * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
685 * or -ENOMEM / -EINVAL on error. If an error is returned, device will switch to
686 * XenbusStateClosing and the first error message will be saved in XenStore.
687 * Further more if we fail to map the ring, caller should check @leaked.
688 * If @leaked is not zero it means xenbus_map_ring fails to clean up, caller
689 * should not free the address space of @vaddr.
691 int xenbus_map_ring(struct xenbus_device *dev, grant_ref_t *gnt_refs,
692 unsigned int nr_grefs, grant_handle_t *handles,
693 unsigned long *vaddrs, bool *leaked)
695 phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
698 if (nr_grefs > XENBUS_MAX_RING_GRANTS)
701 for (i = 0; i < nr_grefs; i++)
702 phys_addrs[i] = (unsigned long)vaddrs[i];
704 return __xenbus_map_ring(dev, gnt_refs, nr_grefs, handles,
705 phys_addrs, GNTMAP_host_map, leaked);
707 EXPORT_SYMBOL_GPL(xenbus_map_ring);
711 * xenbus_unmap_ring_vfree
712 * @dev: xenbus device
713 * @vaddr: addr to unmap
715 * Based on Rusty Russell's skeleton driver's unmap_page.
716 * Unmap a page of memory in this domain that was imported from another domain.
717 * Use xenbus_unmap_ring_vfree if you mapped in your memory with
718 * xenbus_map_ring_valloc (it will free the virtual address space).
719 * Returns 0 on success and returns GNTST_* on error
720 * (see xen/include/interface/grant_table.h).
722 int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
724 return ring_ops->unmap(dev, vaddr);
726 EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree);
728 static int xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev, void *vaddr)
730 struct xenbus_map_node *node;
731 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
737 spin_lock(&xenbus_valloc_lock);
738 list_for_each_entry(node, &xenbus_valloc_pages, next) {
739 if (node->pv.area->addr == vaddr) {
740 list_del(&node->next);
746 spin_unlock(&xenbus_valloc_lock);
749 xenbus_dev_error(dev, -ENOENT,
750 "can't find mapped virtual address %p", vaddr);
751 return GNTST_bad_virt_addr;
754 for (i = 0; i < node->nr_handles; i++) {
757 memset(&unmap[i], 0, sizeof(unmap[i]));
758 addr = (unsigned long)vaddr + (XEN_PAGE_SIZE * i);
759 unmap[i].host_addr = arbitrary_virt_to_machine(
760 lookup_address(addr, &level)).maddr;
761 unmap[i].dev_bus_addr = 0;
762 unmap[i].handle = node->handles[i];
765 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i))
770 for (i = 0; i < node->nr_handles; i++) {
771 if (unmap[i].status != GNTST_okay) {
773 xenbus_dev_error(dev, unmap[i].status,
774 "unmapping page at handle %d error %d",
775 node->handles[i], unmap[i].status);
776 err = unmap[i].status;
782 free_vm_area(node->pv.area);
784 pr_alert("leaking VM area %p size %u page(s)",
785 node->pv.area, node->nr_handles);
791 struct unmap_ring_vfree_hvm
794 unsigned long addrs[XENBUS_MAX_RING_GRANTS];
797 static void xenbus_unmap_ring_setup_grant_hvm(unsigned long gfn,
798 unsigned int goffset,
802 struct unmap_ring_vfree_hvm *info = data;
804 info->addrs[info->idx] = (unsigned long)gfn_to_virt(gfn);
809 static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
812 struct xenbus_map_node *node;
814 struct unmap_ring_vfree_hvm info = {
817 unsigned int nr_pages;
819 spin_lock(&xenbus_valloc_lock);
820 list_for_each_entry(node, &xenbus_valloc_pages, next) {
821 addr = node->hvm.addr;
823 list_del(&node->next);
829 spin_unlock(&xenbus_valloc_lock);
832 xenbus_dev_error(dev, -ENOENT,
833 "can't find mapped virtual address %p", vaddr);
834 return GNTST_bad_virt_addr;
837 nr_pages = XENBUS_PAGES(node->nr_handles);
839 gnttab_foreach_grant(node->hvm.pages, node->nr_handles,
840 xenbus_unmap_ring_setup_grant_hvm,
843 rv = xenbus_unmap_ring(dev, node->handles, node->nr_handles,
847 free_xenballooned_pages(nr_pages, node->hvm.pages);
850 WARN(1, "Leaking %p, size %u page(s)\n", vaddr, nr_pages);
858 * @dev: xenbus device
859 * @handles: grant handle array
860 * @nr_handles: number of handles in the array
861 * @vaddrs: addresses to unmap
863 * Unmap memory in this domain that was imported from another domain.
864 * Returns 0 on success and returns GNTST_* on error
865 * (see xen/include/interface/grant_table.h).
867 int xenbus_unmap_ring(struct xenbus_device *dev,
868 grant_handle_t *handles, unsigned int nr_handles,
869 unsigned long *vaddrs)
871 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
875 if (nr_handles > XENBUS_MAX_RING_GRANTS)
878 for (i = 0; i < nr_handles; i++)
879 gnttab_set_unmap_op(&unmap[i], vaddrs[i],
880 GNTMAP_host_map, handles[i]);
882 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i))
886 for (i = 0; i < nr_handles; i++) {
887 if (unmap[i].status != GNTST_okay) {
888 xenbus_dev_error(dev, unmap[i].status,
889 "unmapping page at handle %d error %d",
890 handles[i], unmap[i].status);
891 err = unmap[i].status;
898 EXPORT_SYMBOL_GPL(xenbus_unmap_ring);
902 * xenbus_read_driver_state
903 * @path: path for driver
905 * Return the state of the driver rooted at the given store path, or
906 * XenbusStateUnknown if no state can be read.
908 enum xenbus_state xenbus_read_driver_state(const char *path)
910 enum xenbus_state result;
911 int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL);
913 result = XenbusStateUnknown;
917 EXPORT_SYMBOL_GPL(xenbus_read_driver_state);
919 static const struct xenbus_ring_ops ring_ops_pv = {
920 .map = xenbus_map_ring_valloc_pv,
921 .unmap = xenbus_unmap_ring_vfree_pv,
924 static const struct xenbus_ring_ops ring_ops_hvm = {
925 .map = xenbus_map_ring_valloc_hvm,
926 .unmap = xenbus_unmap_ring_vfree_hvm,
929 void __init xenbus_ring_ops_init(void)
931 if (!xen_feature(XENFEAT_auto_translated_physmap))
932 ring_ops = &ring_ops_pv;
934 ring_ops = &ring_ops_hvm;