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>
50 #include "xenbus_probe.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 bool (*will_handle)(struct xenbus_watch *,
118 const char **, unsigned int),
119 void (*callback)(struct xenbus_watch *,
120 const char **, unsigned int))
125 watch->will_handle = will_handle;
126 watch->callback = callback;
128 err = register_xenbus_watch(watch);
132 watch->will_handle = NULL;
133 watch->callback = NULL;
134 xenbus_dev_fatal(dev, err, "adding watch on %s", path);
139 EXPORT_SYMBOL_GPL(xenbus_watch_path);
143 * xenbus_watch_pathfmt - register a watch on a sprintf-formatted path
144 * @dev: xenbus device
145 * @watch: watch to register
146 * @callback: callback to register
147 * @pathfmt: format of path to watch
149 * Register a watch on the given @path, using the given xenbus_watch
150 * structure for storage, and the given @callback function as the callback.
151 * Return 0 on success, or -errno on error. On success, the watched path
152 * (@path/@path2) will be saved as @watch->node, and becomes the caller's to
153 * kfree(). On error, watch->node will be NULL, so the caller has nothing to
154 * free, the device will switch to %XenbusStateClosing, and the error will be
155 * saved in the store.
157 int xenbus_watch_pathfmt(struct xenbus_device *dev,
158 struct xenbus_watch *watch,
159 bool (*will_handle)(struct xenbus_watch *,
160 const char **, unsigned int),
161 void (*callback)(struct xenbus_watch *,
162 const char **, unsigned int),
163 const char *pathfmt, ...)
169 va_start(ap, pathfmt);
170 path = kvasprintf(GFP_NOIO | __GFP_HIGH, pathfmt, ap);
174 xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch");
177 err = xenbus_watch_path(dev, path, watch, will_handle, callback);
183 EXPORT_SYMBOL_GPL(xenbus_watch_pathfmt);
185 static void xenbus_switch_fatal(struct xenbus_device *, int, int,
189 __xenbus_switch_state(struct xenbus_device *dev,
190 enum xenbus_state state, int depth)
192 /* We check whether the state is currently set to the given value, and
193 if not, then the state is set. We don't want to unconditionally
194 write the given state, because we don't want to fire watches
195 unnecessarily. Furthermore, if the node has gone, we don't write
196 to it, as the device will be tearing down, and we don't want to
197 resurrect that directory.
199 Note that, because of this cached value of our state, this
200 function will not take a caller's Xenstore transaction
201 (something it was trying to in the past) because dev->state
202 would not get reset if the transaction was aborted.
205 struct xenbus_transaction xbt;
209 if (state == dev->state)
215 err = xenbus_transaction_start(&xbt);
217 xenbus_switch_fatal(dev, depth, err, "starting transaction");
221 err = xenbus_scanf(xbt, dev->nodename, "state", "%d", ¤t_state);
225 err = xenbus_printf(xbt, dev->nodename, "state", "%d", state);
227 xenbus_switch_fatal(dev, depth, err, "writing new state");
233 err = xenbus_transaction_end(xbt, abort);
235 if (err == -EAGAIN && !abort)
237 xenbus_switch_fatal(dev, depth, err, "ending transaction");
245 * xenbus_switch_state
246 * @dev: xenbus device
249 * Advertise in the store a change of the given driver to the given new_state.
250 * Return 0 on success, or -errno on error. On error, the device will switch
251 * to XenbusStateClosing, and the error will be saved in the store.
253 int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state)
255 return __xenbus_switch_state(dev, state, 0);
258 EXPORT_SYMBOL_GPL(xenbus_switch_state);
260 int xenbus_frontend_closed(struct xenbus_device *dev)
262 xenbus_switch_state(dev, XenbusStateClosed);
263 complete(&dev->down);
266 EXPORT_SYMBOL_GPL(xenbus_frontend_closed);
269 * Return the path to the error node for the given device, or NULL on failure.
270 * If the value returned is non-NULL, then it is the caller's to kfree.
272 static char *error_path(struct xenbus_device *dev)
274 return kasprintf(GFP_KERNEL, "error/%s", dev->nodename);
278 static void xenbus_va_dev_error(struct xenbus_device *dev, int err,
279 const char *fmt, va_list ap)
282 char *printf_buffer = NULL;
283 char *path_buffer = NULL;
285 #define PRINTF_BUFFER_SIZE 4096
286 printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL);
287 if (printf_buffer == NULL)
290 len = sprintf(printf_buffer, "%i ", -err);
291 vsnprintf(printf_buffer+len, PRINTF_BUFFER_SIZE-len, fmt, ap);
293 dev_err(&dev->dev, "%s\n", printf_buffer);
295 path_buffer = error_path(dev);
297 if (path_buffer == NULL) {
298 dev_err(&dev->dev, "failed to write error node for %s (%s)\n",
299 dev->nodename, printf_buffer);
303 if (xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer) != 0) {
304 dev_err(&dev->dev, "failed to write error node for %s (%s)\n",
305 dev->nodename, printf_buffer);
310 kfree(printf_buffer);
317 * @dev: xenbus device
318 * @err: error to report
319 * @fmt: error message format
321 * Report the given negative errno into the store, along with the given
324 void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...)
329 xenbus_va_dev_error(dev, err, fmt, ap);
332 EXPORT_SYMBOL_GPL(xenbus_dev_error);
336 * @dev: xenbus device
337 * @err: error to report
338 * @fmt: error message format
340 * Equivalent to xenbus_dev_error(dev, err, fmt, args), followed by
341 * xenbus_switch_state(dev, XenbusStateClosing) to schedule an orderly
342 * closedown of this driver and its peer.
345 void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...)
350 xenbus_va_dev_error(dev, err, fmt, ap);
353 xenbus_switch_state(dev, XenbusStateClosing);
355 EXPORT_SYMBOL_GPL(xenbus_dev_fatal);
358 * Equivalent to xenbus_dev_fatal(dev, err, fmt, args), but helps
359 * avoiding recursion within xenbus_switch_state.
361 static void xenbus_switch_fatal(struct xenbus_device *dev, int depth, int err,
362 const char *fmt, ...)
367 xenbus_va_dev_error(dev, err, fmt, ap);
371 __xenbus_switch_state(dev, XenbusStateClosing, 1);
376 * @dev: xenbus device
377 * @vaddr: starting virtual address of the ring
378 * @nr_pages: number of pages to be granted
379 * @grefs: grant reference array to be filled in
381 * Grant access to the given @vaddr to the peer of the given device.
382 * Then fill in @grefs with grant references. Return 0 on success, or
383 * -errno on error. On error, the device will switch to
384 * XenbusStateClosing, and the error will be saved in the store.
386 int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
387 unsigned int nr_pages, grant_ref_t *grefs)
392 for (i = 0; i < nr_pages; i++) {
395 if (is_vmalloc_addr(vaddr))
396 gfn = pfn_to_gfn(vmalloc_to_pfn(vaddr));
398 gfn = virt_to_gfn(vaddr);
400 err = gnttab_grant_foreign_access(dev->otherend_id, gfn, 0);
402 xenbus_dev_fatal(dev, err,
403 "granting access to ring page");
408 vaddr = vaddr + XEN_PAGE_SIZE;
414 for (j = 0; j < i; j++)
415 gnttab_end_foreign_access_ref(grefs[j], 0);
418 EXPORT_SYMBOL_GPL(xenbus_grant_ring);
422 * Allocate an event channel for the given xenbus_device, assigning the newly
423 * created local port to *port. Return 0 on success, or -errno on error. On
424 * error, the device will switch to XenbusStateClosing, and the error will be
425 * saved in the store.
427 int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port)
429 struct evtchn_alloc_unbound alloc_unbound;
432 alloc_unbound.dom = DOMID_SELF;
433 alloc_unbound.remote_dom = dev->otherend_id;
435 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
438 xenbus_dev_fatal(dev, err, "allocating event channel");
440 *port = alloc_unbound.port;
444 EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn);
448 * Free an existing event channel. Returns 0 on success or -errno on error.
450 int xenbus_free_evtchn(struct xenbus_device *dev, int port)
452 struct evtchn_close close;
457 err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
459 xenbus_dev_error(dev, err, "freeing event channel %d", port);
463 EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
467 * xenbus_map_ring_valloc
468 * @dev: xenbus device
469 * @gnt_refs: grant reference array
470 * @nr_grefs: number of grant references
471 * @vaddr: pointer to address to be filled out by mapping
473 * Map @nr_grefs pages of memory into this domain from another
474 * domain's grant table. xenbus_map_ring_valloc allocates @nr_grefs
475 * pages of virtual address space, maps the pages to that address, and
476 * sets *vaddr to that address. Returns 0 on success, and GNTST_*
477 * (see xen/include/interface/grant_table.h) or -ENOMEM / -EINVAL on
478 * error. If an error is returned, device will switch to
479 * XenbusStateClosing and the error message will be saved in XenStore.
481 int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
482 unsigned int nr_grefs, void **vaddr)
486 err = ring_ops->map(dev, gnt_refs, nr_grefs, vaddr);
487 /* Some hypervisors are buggy and can return 1. */
489 err = GNTST_general_error;
493 EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);
495 /* N.B. sizeof(phys_addr_t) doesn't always equal to sizeof(unsigned
496 * long), e.g. 32-on-64. Caller is responsible for preparing the
497 * right array to feed into this function */
498 static int __xenbus_map_ring(struct xenbus_device *dev,
499 grant_ref_t *gnt_refs,
500 unsigned int nr_grefs,
501 grant_handle_t *handles,
506 struct gnttab_map_grant_ref map[XENBUS_MAX_RING_GRANTS];
507 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
509 int err = GNTST_okay;
511 if (nr_grefs > XENBUS_MAX_RING_GRANTS)
514 for (i = 0; i < nr_grefs; i++) {
515 memset(&map[i], 0, sizeof(map[i]));
516 gnttab_set_map_op(&map[i], addrs[i], flags, gnt_refs[i],
518 handles[i] = INVALID_GRANT_HANDLE;
521 gnttab_batch_map(map, i);
523 for (i = 0; i < nr_grefs; i++) {
524 if (map[i].status != GNTST_okay) {
526 xenbus_dev_fatal(dev, map[i].status,
527 "mapping in shared page %d from domain %d",
528 gnt_refs[i], dev->otherend_id);
531 handles[i] = map[i].handle;
537 for (i = j = 0; i < nr_grefs; i++) {
538 if (handles[i] != INVALID_GRANT_HANDLE) {
539 memset(&unmap[j], 0, sizeof(unmap[j]));
540 gnttab_set_unmap_op(&unmap[j], (phys_addr_t)addrs[i],
541 GNTMAP_host_map, handles[i]);
546 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, j))
550 for (i = 0; i < j; i++) {
551 if (unmap[i].status != GNTST_okay) {
560 static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
561 grant_ref_t *gnt_refs,
562 unsigned int nr_grefs,
565 struct xenbus_map_node *node;
566 struct vm_struct *area;
567 pte_t *ptes[XENBUS_MAX_RING_GRANTS];
568 phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
569 int err = GNTST_okay;
575 if (nr_grefs > XENBUS_MAX_RING_GRANTS)
578 node = kzalloc(sizeof(*node), GFP_KERNEL);
582 area = alloc_vm_area(XEN_PAGE_SIZE * nr_grefs, ptes);
588 for (i = 0; i < nr_grefs; i++)
589 phys_addrs[i] = arbitrary_virt_to_machine(ptes[i]).maddr;
591 err = __xenbus_map_ring(dev, gnt_refs, nr_grefs, node->handles,
593 GNTMAP_host_map | GNTMAP_contains_pte,
598 node->nr_handles = nr_grefs;
599 node->pv.area = area;
601 spin_lock(&xenbus_valloc_lock);
602 list_add(&node->next, &xenbus_valloc_pages);
603 spin_unlock(&xenbus_valloc_lock);
612 pr_alert("leaking VM area %p size %u page(s)", area, nr_grefs);
618 struct map_ring_valloc_hvm
622 /* Why do we need two arrays? See comment of __xenbus_map_ring */
623 phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
624 unsigned long addrs[XENBUS_MAX_RING_GRANTS];
627 static void xenbus_map_ring_setup_grant_hvm(unsigned long gfn,
628 unsigned int goffset,
632 struct map_ring_valloc_hvm *info = data;
633 unsigned long vaddr = (unsigned long)gfn_to_virt(gfn);
635 info->phys_addrs[info->idx] = vaddr;
636 info->addrs[info->idx] = vaddr;
641 static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
642 grant_ref_t *gnt_ref,
643 unsigned int nr_grefs,
646 struct xenbus_map_node *node;
650 struct map_ring_valloc_hvm info = {
653 unsigned int nr_pages = XENBUS_PAGES(nr_grefs);
655 if (nr_grefs > XENBUS_MAX_RING_GRANTS)
660 node = kzalloc(sizeof(*node), GFP_KERNEL);
664 err = alloc_xenballooned_pages(nr_pages, node->hvm.pages);
668 gnttab_foreach_grant(node->hvm.pages, nr_grefs,
669 xenbus_map_ring_setup_grant_hvm,
672 err = __xenbus_map_ring(dev, gnt_ref, nr_grefs, node->handles,
673 info.phys_addrs, GNTMAP_host_map, &leaked);
674 node->nr_handles = nr_grefs;
677 goto out_free_ballooned_pages;
679 addr = vmap(node->hvm.pages, nr_pages, VM_MAP | VM_IOREMAP,
683 goto out_xenbus_unmap_ring;
686 node->hvm.addr = addr;
688 spin_lock(&xenbus_valloc_lock);
689 list_add(&node->next, &xenbus_valloc_pages);
690 spin_unlock(&xenbus_valloc_lock);
695 out_xenbus_unmap_ring:
697 xenbus_unmap_ring(dev, node->handles, nr_grefs, info.addrs);
699 pr_alert("leaking %p size %u page(s)",
701 out_free_ballooned_pages:
703 free_xenballooned_pages(nr_pages, node->hvm.pages);
712 * @dev: xenbus device
713 * @gnt_refs: grant reference array
714 * @nr_grefs: number of grant reference
715 * @handles: pointer to grant handle to be filled
716 * @vaddrs: addresses to be mapped to
717 * @leaked: fail to clean up a failed map, caller should not free vaddr
719 * Map pages of memory into this domain from another domain's grant table.
720 * xenbus_map_ring does not allocate the virtual address space (you must do
721 * this yourself!). It only maps in the pages to the specified address.
722 * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
723 * or -ENOMEM / -EINVAL on error. If an error is returned, device will switch to
724 * XenbusStateClosing and the first error message will be saved in XenStore.
725 * Further more if we fail to map the ring, caller should check @leaked.
726 * If @leaked is not zero it means xenbus_map_ring fails to clean up, caller
727 * should not free the address space of @vaddr.
729 int xenbus_map_ring(struct xenbus_device *dev, grant_ref_t *gnt_refs,
730 unsigned int nr_grefs, grant_handle_t *handles,
731 unsigned long *vaddrs, bool *leaked)
733 phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
736 if (nr_grefs > XENBUS_MAX_RING_GRANTS)
739 for (i = 0; i < nr_grefs; i++)
740 phys_addrs[i] = (unsigned long)vaddrs[i];
742 return __xenbus_map_ring(dev, gnt_refs, nr_grefs, handles,
743 phys_addrs, GNTMAP_host_map, leaked);
745 EXPORT_SYMBOL_GPL(xenbus_map_ring);
749 * xenbus_unmap_ring_vfree
750 * @dev: xenbus device
751 * @vaddr: addr to unmap
753 * Based on Rusty Russell's skeleton driver's unmap_page.
754 * Unmap a page of memory in this domain that was imported from another domain.
755 * Use xenbus_unmap_ring_vfree if you mapped in your memory with
756 * xenbus_map_ring_valloc (it will free the virtual address space).
757 * Returns 0 on success and returns GNTST_* on error
758 * (see xen/include/interface/grant_table.h).
760 int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
762 return ring_ops->unmap(dev, vaddr);
764 EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree);
766 static int xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev, void *vaddr)
768 struct xenbus_map_node *node;
769 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
775 spin_lock(&xenbus_valloc_lock);
776 list_for_each_entry(node, &xenbus_valloc_pages, next) {
777 if (node->pv.area->addr == vaddr) {
778 list_del(&node->next);
784 spin_unlock(&xenbus_valloc_lock);
787 xenbus_dev_error(dev, -ENOENT,
788 "can't find mapped virtual address %p", vaddr);
789 return GNTST_bad_virt_addr;
792 for (i = 0; i < node->nr_handles; i++) {
795 memset(&unmap[i], 0, sizeof(unmap[i]));
796 addr = (unsigned long)vaddr + (XEN_PAGE_SIZE * i);
797 unmap[i].host_addr = arbitrary_virt_to_machine(
798 lookup_address(addr, &level)).maddr;
799 unmap[i].dev_bus_addr = 0;
800 unmap[i].handle = node->handles[i];
803 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i))
808 for (i = 0; i < node->nr_handles; i++) {
809 if (unmap[i].status != GNTST_okay) {
811 xenbus_dev_error(dev, unmap[i].status,
812 "unmapping page at handle %d error %d",
813 node->handles[i], unmap[i].status);
814 err = unmap[i].status;
820 free_vm_area(node->pv.area);
822 pr_alert("leaking VM area %p size %u page(s)",
823 node->pv.area, node->nr_handles);
829 struct unmap_ring_vfree_hvm
832 unsigned long addrs[XENBUS_MAX_RING_GRANTS];
835 static void xenbus_unmap_ring_setup_grant_hvm(unsigned long gfn,
836 unsigned int goffset,
840 struct unmap_ring_vfree_hvm *info = data;
842 info->addrs[info->idx] = (unsigned long)gfn_to_virt(gfn);
847 static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
850 struct xenbus_map_node *node;
852 struct unmap_ring_vfree_hvm info = {
855 unsigned int nr_pages;
857 spin_lock(&xenbus_valloc_lock);
858 list_for_each_entry(node, &xenbus_valloc_pages, next) {
859 addr = node->hvm.addr;
861 list_del(&node->next);
867 spin_unlock(&xenbus_valloc_lock);
870 xenbus_dev_error(dev, -ENOENT,
871 "can't find mapped virtual address %p", vaddr);
872 return GNTST_bad_virt_addr;
875 nr_pages = XENBUS_PAGES(node->nr_handles);
877 gnttab_foreach_grant(node->hvm.pages, node->nr_handles,
878 xenbus_unmap_ring_setup_grant_hvm,
881 rv = xenbus_unmap_ring(dev, node->handles, node->nr_handles,
885 free_xenballooned_pages(nr_pages, node->hvm.pages);
888 WARN(1, "Leaking %p, size %u page(s)\n", vaddr, nr_pages);
896 * @dev: xenbus device
897 * @handles: grant handle array
898 * @nr_handles: number of handles in the array
899 * @vaddrs: addresses to unmap
901 * Unmap memory in this domain that was imported from another domain.
902 * Returns 0 on success and returns GNTST_* on error
903 * (see xen/include/interface/grant_table.h).
905 int xenbus_unmap_ring(struct xenbus_device *dev,
906 grant_handle_t *handles, unsigned int nr_handles,
907 unsigned long *vaddrs)
909 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
913 if (nr_handles > XENBUS_MAX_RING_GRANTS)
916 for (i = 0; i < nr_handles; i++)
917 gnttab_set_unmap_op(&unmap[i], vaddrs[i],
918 GNTMAP_host_map, handles[i]);
920 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i))
924 for (i = 0; i < nr_handles; i++) {
925 if (unmap[i].status != GNTST_okay) {
926 xenbus_dev_error(dev, unmap[i].status,
927 "unmapping page at handle %d error %d",
928 handles[i], unmap[i].status);
929 err = unmap[i].status;
936 EXPORT_SYMBOL_GPL(xenbus_unmap_ring);
940 * xenbus_read_driver_state
941 * @path: path for driver
943 * Return the state of the driver rooted at the given store path, or
944 * XenbusStateUnknown if no state can be read.
946 enum xenbus_state xenbus_read_driver_state(const char *path)
948 enum xenbus_state result;
949 int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL);
951 result = XenbusStateUnknown;
955 EXPORT_SYMBOL_GPL(xenbus_read_driver_state);
957 static const struct xenbus_ring_ops ring_ops_pv = {
958 .map = xenbus_map_ring_valloc_pv,
959 .unmap = xenbus_unmap_ring_vfree_pv,
962 static const struct xenbus_ring_ops ring_ops_hvm = {
963 .map = xenbus_map_ring_valloc_hvm,
964 .unmap = xenbus_unmap_ring_vfree_hvm,
967 void __init xenbus_ring_ops_init(void)
969 if (!xen_feature(XENFEAT_auto_translated_physmap))
970 ring_ops = &ring_ops_pv;
972 ring_ops = &ring_ops_hvm;