1 /******************************************************************************
4 * Granting foreign access to our memory reservation.
6 * Copyright (c) 2005-2006, Christopher Clark
7 * Copyright (c) 2004-2005, K A Fraser
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License version 2
11 * as published by the Free Software Foundation; or, when distributed
12 * separately from the Linux kernel or incorporated into other
13 * software packages, subject to the following license:
15 * Permission is hereby granted, free of charge, to any person obtaining a copy
16 * of this source file (the "Software"), to deal in the Software without
17 * restriction, including without limitation the rights to use, copy, modify,
18 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
19 * and to permit persons to whom the Software is furnished to do so, subject to
20 * the following conditions:
22 * The above copyright notice and this permission notice shall be included in
23 * all copies or substantial portions of the Software.
25 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
26 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
27 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
28 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
29 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
30 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
34 #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
36 #include <linux/module.h>
37 #include <linux/sched.h>
39 #include <linux/slab.h>
40 #include <linux/vmalloc.h>
41 #include <linux/uaccess.h>
43 #include <linux/delay.h>
44 #include <linux/hardirq.h>
45 #include <linux/workqueue.h>
48 #include <xen/interface/xen.h>
50 #include <xen/grant_table.h>
51 #include <xen/interface/memory.h>
52 #include <xen/hvc-console.h>
53 #include <xen/swiotlb-xen.h>
54 #include <xen/balloon.h>
55 #include <asm/xen/hypercall.h>
56 #include <asm/xen/interface.h>
58 #include <asm/pgtable.h>
59 #include <asm/sync_bitops.h>
61 /* External tools reserve first few grant table entries. */
62 #define NR_RESERVED_ENTRIES 8
63 #define GNTTAB_LIST_END 0xffffffff
65 static grant_ref_t **gnttab_list;
66 static unsigned int nr_grant_frames;
67 static int gnttab_free_count;
68 static grant_ref_t gnttab_free_head;
69 static DEFINE_SPINLOCK(gnttab_list_lock);
70 struct grant_frames xen_auto_xlat_grant_frames;
73 struct grant_entry_v1 *v1;
77 /*This is a structure of function pointers for grant table*/
80 * Mapping a list of frames for storing grant entries. Frames parameter
81 * is used to store grant table address when grant table being setup,
82 * nr_gframes is the number of frames to map grant table. Returning
83 * GNTST_okay means success and negative value means failure.
85 int (*map_frames)(xen_pfn_t *frames, unsigned int nr_gframes);
87 * Release a list of frames which are mapped in map_frames for grant
90 void (*unmap_frames)(void);
92 * Introducing a valid entry into the grant table, granting the frame of
93 * this grant entry to domain for accessing or transfering. Ref
94 * parameter is reference of this introduced grant entry, domid is id of
95 * granted domain, frame is the page frame to be granted, and flags is
96 * status of the grant entry to be updated.
98 void (*update_entry)(grant_ref_t ref, domid_t domid,
99 unsigned long frame, unsigned flags);
101 * Stop granting a grant entry to domain for accessing. Ref parameter is
102 * reference of a grant entry whose grant access will be stopped,
103 * readonly is not in use in this function. If the grant entry is
104 * currently mapped for reading or writing, just return failure(==0)
105 * directly and don't tear down the grant access. Otherwise, stop grant
106 * access for this entry and return success(==1).
108 int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);
110 * Stop granting a grant entry to domain for transfer. Ref parameter is
111 * reference of a grant entry whose grant transfer will be stopped. If
112 * tranfer has not started, just reclaim the grant entry and return
113 * failure(==0). Otherwise, wait for the transfer to complete and then
116 unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
118 * Query the status of a grant entry. Ref parameter is reference of
119 * queried grant entry, return value is the status of queried entry.
120 * Detailed status(writing/reading) can be gotten from the return value
123 int (*query_foreign_access)(grant_ref_t ref);
126 static struct gnttab_ops *gnttab_interface;
128 static int grant_table_version;
129 static int grefs_per_grant_frame;
131 static struct gnttab_free_callback *gnttab_free_callback_list;
133 static int gnttab_expand(unsigned int req_entries);
135 #define RPP (PAGE_SIZE / sizeof(grant_ref_t))
136 #define SPP (PAGE_SIZE / sizeof(grant_status_t))
138 static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
140 return &gnttab_list[(entry) / RPP][(entry) % RPP];
142 /* This can be used as an l-value */
143 #define gnttab_entry(entry) (*__gnttab_entry(entry))
145 static int get_free_entries(unsigned count)
151 spin_lock_irqsave(&gnttab_list_lock, flags);
153 if ((gnttab_free_count < count) &&
154 ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
155 spin_unlock_irqrestore(&gnttab_list_lock, flags);
159 ref = head = gnttab_free_head;
160 gnttab_free_count -= count;
162 head = gnttab_entry(head);
163 gnttab_free_head = gnttab_entry(head);
164 gnttab_entry(head) = GNTTAB_LIST_END;
166 spin_unlock_irqrestore(&gnttab_list_lock, flags);
171 static void do_free_callbacks(void)
173 struct gnttab_free_callback *callback, *next;
175 callback = gnttab_free_callback_list;
176 gnttab_free_callback_list = NULL;
178 while (callback != NULL) {
179 next = callback->next;
180 if (gnttab_free_count >= callback->count) {
181 callback->next = NULL;
182 callback->fn(callback->arg);
184 callback->next = gnttab_free_callback_list;
185 gnttab_free_callback_list = callback;
191 static inline void check_free_callbacks(void)
193 if (unlikely(gnttab_free_callback_list))
197 static void put_free_entry(grant_ref_t ref)
200 spin_lock_irqsave(&gnttab_list_lock, flags);
201 gnttab_entry(ref) = gnttab_free_head;
202 gnttab_free_head = ref;
204 check_free_callbacks();
205 spin_unlock_irqrestore(&gnttab_list_lock, flags);
209 * Following applies to gnttab_update_entry_v1.
210 * Introducing a valid entry into the grant table:
211 * 1. Write ent->domid.
212 * 2. Write ent->frame:
213 * GTF_permit_access: Frame to which access is permitted.
214 * GTF_accept_transfer: Pseudo-phys frame slot being filled by new
215 * frame, or zero if none.
216 * 3. Write memory barrier (WMB).
217 * 4. Write ent->flags, inc. valid type.
219 static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
220 unsigned long frame, unsigned flags)
222 gnttab_shared.v1[ref].domid = domid;
223 gnttab_shared.v1[ref].frame = frame;
225 gnttab_shared.v1[ref].flags = flags;
229 * Public grant-issuing interface functions
231 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
232 unsigned long frame, int readonly)
234 gnttab_interface->update_entry(ref, domid, frame,
235 GTF_permit_access | (readonly ? GTF_readonly : 0));
237 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
239 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
244 ref = get_free_entries(1);
245 if (unlikely(ref < 0))
248 gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
252 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
254 static int gnttab_query_foreign_access_v1(grant_ref_t ref)
256 return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
259 int gnttab_query_foreign_access(grant_ref_t ref)
261 return gnttab_interface->query_foreign_access(ref);
263 EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
265 static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
270 pflags = &gnttab_shared.v1[ref].flags;
274 if (flags & (GTF_reading|GTF_writing))
276 } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
281 static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
283 return gnttab_interface->end_foreign_access_ref(ref, readonly);
286 int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
288 if (_gnttab_end_foreign_access_ref(ref, readonly))
290 pr_warn("WARNING: g.e. %#x still in use!\n", ref);
293 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
295 struct deferred_entry {
296 struct list_head list;
302 static LIST_HEAD(deferred_list);
303 static void gnttab_handle_deferred(unsigned long);
304 static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred, 0, 0);
306 static void gnttab_handle_deferred(unsigned long unused)
308 unsigned int nr = 10;
309 struct deferred_entry *first = NULL;
312 spin_lock_irqsave(&gnttab_list_lock, flags);
314 struct deferred_entry *entry
315 = list_first_entry(&deferred_list,
316 struct deferred_entry, list);
320 list_del(&entry->list);
321 spin_unlock_irqrestore(&gnttab_list_lock, flags);
322 if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
323 put_free_entry(entry->ref);
325 pr_debug("freeing g.e. %#x (pfn %#lx)\n",
326 entry->ref, page_to_pfn(entry->page));
327 __free_page(entry->page);
329 pr_info("freeing g.e. %#x\n", entry->ref);
333 if (!--entry->warn_delay)
334 pr_info("g.e. %#x still pending\n", entry->ref);
338 spin_lock_irqsave(&gnttab_list_lock, flags);
340 list_add_tail(&entry->list, &deferred_list);
341 else if (list_empty(&deferred_list))
344 if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
345 deferred_timer.expires = jiffies + HZ;
346 add_timer(&deferred_timer);
348 spin_unlock_irqrestore(&gnttab_list_lock, flags);
351 static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
354 struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
355 const char *what = KERN_WARNING "leaking";
361 entry->ro = readonly;
363 entry->warn_delay = 60;
364 spin_lock_irqsave(&gnttab_list_lock, flags);
365 list_add_tail(&entry->list, &deferred_list);
366 if (!timer_pending(&deferred_timer)) {
367 deferred_timer.expires = jiffies + HZ;
368 add_timer(&deferred_timer);
370 spin_unlock_irqrestore(&gnttab_list_lock, flags);
371 what = KERN_DEBUG "deferring";
373 printk("%s g.e. %#x (pfn %#lx)\n",
374 what, ref, page ? page_to_pfn(page) : -1);
377 void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
380 if (gnttab_end_foreign_access_ref(ref, readonly)) {
385 gnttab_add_deferred(ref, readonly,
386 page ? virt_to_page(page) : NULL);
388 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
390 int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
394 ref = get_free_entries(1);
395 if (unlikely(ref < 0))
397 gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
401 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
403 void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
406 gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
408 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
410 static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
416 pflags = &gnttab_shared.v1[ref].flags;
419 * If a transfer is not even yet started, try to reclaim the grant
420 * reference and return failure (== 0).
422 while (!((flags = *pflags) & GTF_transfer_committed)) {
423 if (sync_cmpxchg(pflags, flags, 0) == flags)
428 /* If a transfer is in progress then wait until it is completed. */
429 while (!(flags & GTF_transfer_completed)) {
434 rmb(); /* Read the frame number /after/ reading completion status. */
435 frame = gnttab_shared.v1[ref].frame;
441 unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
443 return gnttab_interface->end_foreign_transfer_ref(ref);
445 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
447 unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
449 unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
453 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
455 void gnttab_free_grant_reference(grant_ref_t ref)
459 EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
461 void gnttab_free_grant_references(grant_ref_t head)
466 if (head == GNTTAB_LIST_END)
468 spin_lock_irqsave(&gnttab_list_lock, flags);
470 while (gnttab_entry(ref) != GNTTAB_LIST_END) {
471 ref = gnttab_entry(ref);
474 gnttab_entry(ref) = gnttab_free_head;
475 gnttab_free_head = head;
476 gnttab_free_count += count;
477 check_free_callbacks();
478 spin_unlock_irqrestore(&gnttab_list_lock, flags);
480 EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
482 int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
484 int h = get_free_entries(count);
493 EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
495 int gnttab_empty_grant_references(const grant_ref_t *private_head)
497 return (*private_head == GNTTAB_LIST_END);
499 EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
501 int gnttab_claim_grant_reference(grant_ref_t *private_head)
503 grant_ref_t g = *private_head;
504 if (unlikely(g == GNTTAB_LIST_END))
506 *private_head = gnttab_entry(g);
509 EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
511 void gnttab_release_grant_reference(grant_ref_t *private_head,
514 gnttab_entry(release) = *private_head;
515 *private_head = release;
517 EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
519 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
520 void (*fn)(void *), void *arg, u16 count)
523 struct gnttab_free_callback *cb;
525 spin_lock_irqsave(&gnttab_list_lock, flags);
527 /* Check if the callback is already on the list */
528 cb = gnttab_free_callback_list;
537 callback->count = count;
538 callback->next = gnttab_free_callback_list;
539 gnttab_free_callback_list = callback;
540 check_free_callbacks();
542 spin_unlock_irqrestore(&gnttab_list_lock, flags);
544 EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
546 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
548 struct gnttab_free_callback **pcb;
551 spin_lock_irqsave(&gnttab_list_lock, flags);
552 for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
553 if (*pcb == callback) {
554 *pcb = callback->next;
558 spin_unlock_irqrestore(&gnttab_list_lock, flags);
560 EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
562 static int grow_gnttab_list(unsigned int more_frames)
564 unsigned int new_nr_grant_frames, extra_entries, i;
565 unsigned int nr_glist_frames, new_nr_glist_frames;
567 BUG_ON(grefs_per_grant_frame == 0);
569 new_nr_grant_frames = nr_grant_frames + more_frames;
570 extra_entries = more_frames * grefs_per_grant_frame;
572 nr_glist_frames = (nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
573 new_nr_glist_frames =
574 (new_nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
575 for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
576 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
582 for (i = grefs_per_grant_frame * nr_grant_frames;
583 i < grefs_per_grant_frame * new_nr_grant_frames - 1; i++)
584 gnttab_entry(i) = i + 1;
586 gnttab_entry(i) = gnttab_free_head;
587 gnttab_free_head = grefs_per_grant_frame * nr_grant_frames;
588 gnttab_free_count += extra_entries;
590 nr_grant_frames = new_nr_grant_frames;
592 check_free_callbacks();
597 while (i-- > nr_glist_frames)
598 free_page((unsigned long) gnttab_list[i]);
602 static unsigned int __max_nr_grant_frames(void)
604 struct gnttab_query_size query;
607 query.dom = DOMID_SELF;
609 rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
610 if ((rc < 0) || (query.status != GNTST_okay))
611 return 4; /* Legacy max supported number of frames */
613 return query.max_nr_frames;
616 unsigned int gnttab_max_grant_frames(void)
618 unsigned int xen_max = __max_nr_grant_frames();
619 static unsigned int boot_max_nr_grant_frames;
621 /* First time, initialize it properly. */
622 if (!boot_max_nr_grant_frames)
623 boot_max_nr_grant_frames = __max_nr_grant_frames();
625 if (xen_max > boot_max_nr_grant_frames)
626 return boot_max_nr_grant_frames;
629 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
631 int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
634 unsigned int max_nr_gframes = __max_nr_grant_frames();
638 if (xen_auto_xlat_grant_frames.count)
641 vaddr = xen_remap(addr, PAGE_SIZE * max_nr_gframes);
643 pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
647 pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
652 for (i = 0; i < max_nr_gframes; i++)
653 pfn[i] = PFN_DOWN(addr) + i;
655 xen_auto_xlat_grant_frames.vaddr = vaddr;
656 xen_auto_xlat_grant_frames.pfn = pfn;
657 xen_auto_xlat_grant_frames.count = max_nr_gframes;
661 EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
663 void gnttab_free_auto_xlat_frames(void)
665 if (!xen_auto_xlat_grant_frames.count)
667 kfree(xen_auto_xlat_grant_frames.pfn);
668 xen_unmap(xen_auto_xlat_grant_frames.vaddr);
670 xen_auto_xlat_grant_frames.pfn = NULL;
671 xen_auto_xlat_grant_frames.count = 0;
672 xen_auto_xlat_grant_frames.vaddr = NULL;
674 EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
677 * gnttab_alloc_pages - alloc pages suitable for grant mapping into
678 * @nr_pages: number of pages to alloc
679 * @pages: returns the pages
681 int gnttab_alloc_pages(int nr_pages, struct page **pages)
686 ret = alloc_xenballooned_pages(nr_pages, pages, false);
690 for (i = 0; i < nr_pages; i++) {
691 #if BITS_PER_LONG < 64
692 struct xen_page_foreign *foreign;
694 foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
696 gnttab_free_pages(nr_pages, pages);
699 set_page_private(pages[i], (unsigned long)foreign);
701 SetPagePrivate(pages[i]);
706 EXPORT_SYMBOL(gnttab_alloc_pages);
709 * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
710 * @nr_pages; number of pages to free
713 void gnttab_free_pages(int nr_pages, struct page **pages)
717 for (i = 0; i < nr_pages; i++) {
718 if (PagePrivate(pages[i])) {
719 #if BITS_PER_LONG < 64
720 kfree((void *)page_private(pages[i]));
722 ClearPagePrivate(pages[i]);
725 free_xenballooned_pages(nr_pages, pages);
727 EXPORT_SYMBOL(gnttab_free_pages);
729 /* Handling of paged out grant targets (GNTST_eagain) */
730 #define MAX_DELAY 256
732 gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
738 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
739 if (*status == GNTST_eagain)
741 } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
743 if (delay >= MAX_DELAY) {
744 pr_err("%s: %s eagain grant\n", func, current->comm);
745 *status = GNTST_bad_page;
749 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
751 struct gnttab_map_grant_ref *op;
753 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
755 for (op = batch; op < batch + count; op++)
756 if (op->status == GNTST_eagain)
757 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
758 &op->status, __func__);
760 EXPORT_SYMBOL_GPL(gnttab_batch_map);
762 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
764 struct gnttab_copy *op;
766 if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
768 for (op = batch; op < batch + count; op++)
769 if (op->status == GNTST_eagain)
770 gnttab_retry_eagain_gop(GNTTABOP_copy, op,
771 &op->status, __func__);
773 EXPORT_SYMBOL_GPL(gnttab_batch_copy);
775 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
776 struct gnttab_map_grant_ref *kmap_ops,
777 struct page **pages, unsigned int count)
781 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
785 for (i = 0; i < count; i++) {
786 /* Retry eagain maps */
787 if (map_ops[i].status == GNTST_eagain)
788 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i,
789 &map_ops[i].status, __func__);
791 if (map_ops[i].status == GNTST_okay) {
792 struct xen_page_foreign *foreign;
794 SetPageForeign(pages[i]);
795 foreign = xen_page_foreign(pages[i]);
796 foreign->domid = map_ops[i].dom;
797 foreign->gref = map_ops[i].ref;
801 return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
803 EXPORT_SYMBOL_GPL(gnttab_map_refs);
805 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
806 struct gnttab_unmap_grant_ref *kunmap_ops,
807 struct page **pages, unsigned int count)
812 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
816 for (i = 0; i < count; i++)
817 ClearPageForeign(pages[i]);
819 return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
821 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
823 #define GNTTAB_UNMAP_REFS_DELAY 5
825 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
827 static void gnttab_unmap_work(struct work_struct *work)
829 struct gntab_unmap_queue_data
830 *unmap_data = container_of(work,
831 struct gntab_unmap_queue_data,
833 if (unmap_data->age != UINT_MAX)
835 __gnttab_unmap_refs_async(unmap_data);
838 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
843 for (pc = 0; pc < item->count; pc++) {
844 if (page_count(item->pages[pc]) > 1) {
845 unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
846 schedule_delayed_work(&item->gnttab_work,
847 msecs_to_jiffies(delay));
852 ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
853 item->pages, item->count);
854 item->done(ret, item);
857 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
859 INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
862 __gnttab_unmap_refs_async(item);
864 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
866 static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
870 rc = arch_gnttab_map_shared(frames, nr_gframes,
871 gnttab_max_grant_frames(),
872 &gnttab_shared.addr);
878 static void gnttab_unmap_frames_v1(void)
880 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
883 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
885 struct gnttab_setup_table setup;
887 unsigned int nr_gframes = end_idx + 1;
890 if (xen_feature(XENFEAT_auto_translated_physmap)) {
891 struct xen_add_to_physmap xatp;
892 unsigned int i = end_idx;
894 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
896 * Loop backwards, so that the first hypercall has the largest
897 * index, ensuring that the table will grow only once.
900 xatp.domid = DOMID_SELF;
902 xatp.space = XENMAPSPACE_grant_table;
903 xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
904 rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
906 pr_warn("grant table add_to_physmap failed, err=%d\n",
910 } while (i-- > start_idx);
915 /* No need for kzalloc as it is initialized in following hypercall
916 * GNTTABOP_setup_table.
918 frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC);
922 setup.dom = DOMID_SELF;
923 setup.nr_frames = nr_gframes;
924 set_xen_guest_handle(setup.frame_list, frames);
926 rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
932 BUG_ON(rc || setup.status);
934 rc = gnttab_interface->map_frames(frames, nr_gframes);
941 static struct gnttab_ops gnttab_v1_ops = {
942 .map_frames = gnttab_map_frames_v1,
943 .unmap_frames = gnttab_unmap_frames_v1,
944 .update_entry = gnttab_update_entry_v1,
945 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v1,
946 .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v1,
947 .query_foreign_access = gnttab_query_foreign_access_v1,
950 static void gnttab_request_version(void)
952 /* Only version 1 is used, which will always be available. */
953 grant_table_version = 1;
954 grefs_per_grant_frame = PAGE_SIZE / sizeof(struct grant_entry_v1);
955 gnttab_interface = &gnttab_v1_ops;
957 pr_info("Grant tables using version %d layout\n", grant_table_version);
960 static int gnttab_setup(void)
962 unsigned int max_nr_gframes;
964 max_nr_gframes = gnttab_max_grant_frames();
965 if (max_nr_gframes < nr_grant_frames)
968 if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
969 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
970 if (gnttab_shared.addr == NULL) {
971 pr_warn("gnttab share frames (addr=0x%08lx) is not mapped!\n",
972 (unsigned long)xen_auto_xlat_grant_frames.vaddr);
976 return gnttab_map(0, nr_grant_frames - 1);
979 int gnttab_resume(void)
981 gnttab_request_version();
982 return gnttab_setup();
985 int gnttab_suspend(void)
987 if (!xen_feature(XENFEAT_auto_translated_physmap))
988 gnttab_interface->unmap_frames();
992 static int gnttab_expand(unsigned int req_entries)
995 unsigned int cur, extra;
997 BUG_ON(grefs_per_grant_frame == 0);
998 cur = nr_grant_frames;
999 extra = ((req_entries + (grefs_per_grant_frame-1)) /
1000 grefs_per_grant_frame);
1001 if (cur + extra > gnttab_max_grant_frames())
1004 rc = gnttab_map(cur, cur + extra - 1);
1006 rc = grow_gnttab_list(extra);
1011 int gnttab_init(void)
1014 unsigned long max_nr_grant_frames;
1015 unsigned int max_nr_glist_frames, nr_glist_frames;
1016 unsigned int nr_init_grefs;
1019 gnttab_request_version();
1020 max_nr_grant_frames = gnttab_max_grant_frames();
1021 nr_grant_frames = 1;
1023 /* Determine the maximum number of frames required for the
1024 * grant reference free list on the current hypervisor.
1026 BUG_ON(grefs_per_grant_frame == 0);
1027 max_nr_glist_frames = (max_nr_grant_frames *
1028 grefs_per_grant_frame / RPP);
1030 gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *),
1032 if (gnttab_list == NULL)
1035 nr_glist_frames = (nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
1036 for (i = 0; i < nr_glist_frames; i++) {
1037 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1038 if (gnttab_list[i] == NULL) {
1044 ret = arch_gnttab_init(max_nr_grant_frames);
1048 if (gnttab_setup() < 0) {
1053 nr_init_grefs = nr_grant_frames * grefs_per_grant_frame;
1055 for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
1056 gnttab_entry(i) = i + 1;
1058 gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
1059 gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
1060 gnttab_free_head = NR_RESERVED_ENTRIES;
1062 printk("Grant table initialized\n");
1066 for (i--; i >= 0; i--)
1067 free_page((unsigned long)gnttab_list[i]);
1071 EXPORT_SYMBOL_GPL(gnttab_init);
1073 static int __gnttab_init(void)
1075 /* Delay grant-table initialization in the PV on HVM case */
1076 if (xen_hvm_domain())
1079 if (!xen_pv_domain())
1082 return gnttab_init();
1084 /* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1085 * beforehand to initialize xen_auto_xlat_grant_frames. */
1086 core_initcall_sync(__gnttab_init);