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/sched.h>
38 #include <linux/slab.h>
39 #include <linux/vmalloc.h>
40 #include <linux/uaccess.h>
42 #include <linux/delay.h>
43 #include <linux/hardirq.h>
44 #include <linux/workqueue.h>
47 #include <xen/interface/xen.h>
49 #include <xen/grant_table.h>
50 #include <xen/interface/memory.h>
51 #include <xen/hvc-console.h>
52 #include <xen/swiotlb-xen.h>
53 #include <xen/balloon.h>
54 #include <asm/xen/hypercall.h>
55 #include <asm/xen/interface.h>
57 #include <asm/pgtable.h>
58 #include <asm/sync_bitops.h>
60 /* External tools reserve first few grant table entries. */
61 #define NR_RESERVED_ENTRIES 8
62 #define GNTTAB_LIST_END 0xffffffff
64 static grant_ref_t **gnttab_list;
65 static unsigned int nr_grant_frames;
66 static int gnttab_free_count;
67 static grant_ref_t gnttab_free_head;
68 static DEFINE_SPINLOCK(gnttab_list_lock);
69 struct grant_frames xen_auto_xlat_grant_frames;
72 struct grant_entry_v1 *v1;
76 /*This is a structure of function pointers for grant table*/
79 * Mapping a list of frames for storing grant entries. Frames parameter
80 * is used to store grant table address when grant table being setup,
81 * nr_gframes is the number of frames to map grant table. Returning
82 * GNTST_okay means success and negative value means failure.
84 int (*map_frames)(xen_pfn_t *frames, unsigned int nr_gframes);
86 * Release a list of frames which are mapped in map_frames for grant
89 void (*unmap_frames)(void);
91 * Introducing a valid entry into the grant table, granting the frame of
92 * this grant entry to domain for accessing or transfering. Ref
93 * parameter is reference of this introduced grant entry, domid is id of
94 * granted domain, frame is the page frame to be granted, and flags is
95 * status of the grant entry to be updated.
97 void (*update_entry)(grant_ref_t ref, domid_t domid,
98 unsigned long frame, unsigned flags);
100 * Stop granting a grant entry to domain for accessing. Ref parameter is
101 * reference of a grant entry whose grant access will be stopped,
102 * readonly is not in use in this function. If the grant entry is
103 * currently mapped for reading or writing, just return failure(==0)
104 * directly and don't tear down the grant access. Otherwise, stop grant
105 * access for this entry and return success(==1).
107 int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);
109 * Stop granting a grant entry to domain for transfer. Ref parameter is
110 * reference of a grant entry whose grant transfer will be stopped. If
111 * tranfer has not started, just reclaim the grant entry and return
112 * failure(==0). Otherwise, wait for the transfer to complete and then
115 unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
117 * Read the frame number related to a given grant reference.
119 unsigned long (*read_frame)(grant_ref_t ref);
122 struct unmap_refs_callback_data {
123 struct completion completion;
127 static const struct gnttab_ops *gnttab_interface;
129 static int grant_table_version;
130 static int grefs_per_grant_frame;
132 static struct gnttab_free_callback *gnttab_free_callback_list;
134 static int gnttab_expand(unsigned int req_entries);
136 #define RPP (PAGE_SIZE / sizeof(grant_ref_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_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
259 pflags = &gnttab_shared.v1[ref].flags;
263 if (flags & (GTF_reading|GTF_writing))
265 } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
270 static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
272 return gnttab_interface->end_foreign_access_ref(ref, readonly);
275 int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
277 if (_gnttab_end_foreign_access_ref(ref, readonly))
279 pr_warn("WARNING: g.e. %#x still in use!\n", ref);
282 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
284 static unsigned long gnttab_read_frame_v1(grant_ref_t ref)
286 return gnttab_shared.v1[ref].frame;
289 struct deferred_entry {
290 struct list_head list;
296 static LIST_HEAD(deferred_list);
297 static void gnttab_handle_deferred(unsigned long);
298 static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred, 0, 0);
300 static void gnttab_handle_deferred(unsigned long unused)
302 unsigned int nr = 10;
303 struct deferred_entry *first = NULL;
306 spin_lock_irqsave(&gnttab_list_lock, flags);
308 struct deferred_entry *entry
309 = list_first_entry(&deferred_list,
310 struct deferred_entry, list);
314 list_del(&entry->list);
315 spin_unlock_irqrestore(&gnttab_list_lock, flags);
316 if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
317 put_free_entry(entry->ref);
318 pr_debug("freeing g.e. %#x (pfn %#lx)\n",
319 entry->ref, page_to_pfn(entry->page));
320 put_page(entry->page);
324 if (!--entry->warn_delay)
325 pr_info("g.e. %#x still pending\n", entry->ref);
329 spin_lock_irqsave(&gnttab_list_lock, flags);
331 list_add_tail(&entry->list, &deferred_list);
332 else if (list_empty(&deferred_list))
335 if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
336 deferred_timer.expires = jiffies + HZ;
337 add_timer(&deferred_timer);
339 spin_unlock_irqrestore(&gnttab_list_lock, flags);
342 static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
345 struct deferred_entry *entry;
346 gfp_t gfp = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
347 const char *what = KERN_WARNING "leaking";
349 entry = kmalloc(sizeof(*entry), gfp);
351 unsigned long gfn = gnttab_interface->read_frame(ref);
353 page = pfn_to_page(gfn_to_pfn(gfn));
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 int gnttab_try_end_foreign_access(grant_ref_t ref)
379 int ret = _gnttab_end_foreign_access_ref(ref, 0);
386 EXPORT_SYMBOL_GPL(gnttab_try_end_foreign_access);
388 void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
391 if (gnttab_try_end_foreign_access(ref)) {
393 put_page(virt_to_page(page));
395 gnttab_add_deferred(ref, readonly,
396 page ? virt_to_page(page) : NULL);
398 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
400 int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
404 ref = get_free_entries(1);
405 if (unlikely(ref < 0))
407 gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
411 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
413 void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
416 gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
418 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
420 static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
426 pflags = &gnttab_shared.v1[ref].flags;
429 * If a transfer is not even yet started, try to reclaim the grant
430 * reference and return failure (== 0).
432 while (!((flags = *pflags) & GTF_transfer_committed)) {
433 if (sync_cmpxchg(pflags, flags, 0) == flags)
438 /* If a transfer is in progress then wait until it is completed. */
439 while (!(flags & GTF_transfer_completed)) {
444 rmb(); /* Read the frame number /after/ reading completion status. */
445 frame = gnttab_shared.v1[ref].frame;
451 unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
453 return gnttab_interface->end_foreign_transfer_ref(ref);
455 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
457 unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
459 unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
463 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
465 void gnttab_free_grant_reference(grant_ref_t ref)
469 EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
471 void gnttab_free_grant_references(grant_ref_t head)
476 if (head == GNTTAB_LIST_END)
478 spin_lock_irqsave(&gnttab_list_lock, flags);
480 while (gnttab_entry(ref) != GNTTAB_LIST_END) {
481 ref = gnttab_entry(ref);
484 gnttab_entry(ref) = gnttab_free_head;
485 gnttab_free_head = head;
486 gnttab_free_count += count;
487 check_free_callbacks();
488 spin_unlock_irqrestore(&gnttab_list_lock, flags);
490 EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
492 int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
494 int h = get_free_entries(count);
503 EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
505 int gnttab_empty_grant_references(const grant_ref_t *private_head)
507 return (*private_head == GNTTAB_LIST_END);
509 EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
511 int gnttab_claim_grant_reference(grant_ref_t *private_head)
513 grant_ref_t g = *private_head;
514 if (unlikely(g == GNTTAB_LIST_END))
516 *private_head = gnttab_entry(g);
519 EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
521 void gnttab_release_grant_reference(grant_ref_t *private_head,
524 gnttab_entry(release) = *private_head;
525 *private_head = release;
527 EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
529 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
530 void (*fn)(void *), void *arg, u16 count)
533 struct gnttab_free_callback *cb;
535 spin_lock_irqsave(&gnttab_list_lock, flags);
537 /* Check if the callback is already on the list */
538 cb = gnttab_free_callback_list;
547 callback->count = count;
548 callback->next = gnttab_free_callback_list;
549 gnttab_free_callback_list = callback;
550 check_free_callbacks();
552 spin_unlock_irqrestore(&gnttab_list_lock, flags);
554 EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
556 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
558 struct gnttab_free_callback **pcb;
561 spin_lock_irqsave(&gnttab_list_lock, flags);
562 for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
563 if (*pcb == callback) {
564 *pcb = callback->next;
568 spin_unlock_irqrestore(&gnttab_list_lock, flags);
570 EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
572 static int grow_gnttab_list(unsigned int more_frames)
574 unsigned int new_nr_grant_frames, extra_entries, i;
575 unsigned int nr_glist_frames, new_nr_glist_frames;
577 BUG_ON(grefs_per_grant_frame == 0);
579 new_nr_grant_frames = nr_grant_frames + more_frames;
580 extra_entries = more_frames * grefs_per_grant_frame;
582 nr_glist_frames = (nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
583 new_nr_glist_frames =
584 (new_nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
585 for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
586 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
592 for (i = grefs_per_grant_frame * nr_grant_frames;
593 i < grefs_per_grant_frame * new_nr_grant_frames - 1; i++)
594 gnttab_entry(i) = i + 1;
596 gnttab_entry(i) = gnttab_free_head;
597 gnttab_free_head = grefs_per_grant_frame * nr_grant_frames;
598 gnttab_free_count += extra_entries;
600 nr_grant_frames = new_nr_grant_frames;
602 check_free_callbacks();
607 while (i-- > nr_glist_frames)
608 free_page((unsigned long) gnttab_list[i]);
612 static unsigned int __max_nr_grant_frames(void)
614 struct gnttab_query_size query;
617 query.dom = DOMID_SELF;
619 rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
620 if ((rc < 0) || (query.status != GNTST_okay))
621 return 4; /* Legacy max supported number of frames */
623 return query.max_nr_frames;
626 unsigned int gnttab_max_grant_frames(void)
628 unsigned int xen_max = __max_nr_grant_frames();
629 static unsigned int boot_max_nr_grant_frames;
631 /* First time, initialize it properly. */
632 if (!boot_max_nr_grant_frames)
633 boot_max_nr_grant_frames = __max_nr_grant_frames();
635 if (xen_max > boot_max_nr_grant_frames)
636 return boot_max_nr_grant_frames;
639 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
641 int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
644 unsigned int max_nr_gframes = __max_nr_grant_frames();
648 if (xen_auto_xlat_grant_frames.count)
651 vaddr = xen_remap(addr, XEN_PAGE_SIZE * max_nr_gframes);
653 pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
657 pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
662 for (i = 0; i < max_nr_gframes; i++)
663 pfn[i] = XEN_PFN_DOWN(addr) + i;
665 xen_auto_xlat_grant_frames.vaddr = vaddr;
666 xen_auto_xlat_grant_frames.pfn = pfn;
667 xen_auto_xlat_grant_frames.count = max_nr_gframes;
671 EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
673 void gnttab_free_auto_xlat_frames(void)
675 if (!xen_auto_xlat_grant_frames.count)
677 kfree(xen_auto_xlat_grant_frames.pfn);
678 xen_unmap(xen_auto_xlat_grant_frames.vaddr);
680 xen_auto_xlat_grant_frames.pfn = NULL;
681 xen_auto_xlat_grant_frames.count = 0;
682 xen_auto_xlat_grant_frames.vaddr = NULL;
684 EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
687 * gnttab_alloc_pages - alloc pages suitable for grant mapping into
688 * @nr_pages: number of pages to alloc
689 * @pages: returns the pages
691 int gnttab_alloc_pages(int nr_pages, struct page **pages)
696 ret = alloc_xenballooned_pages(nr_pages, pages);
700 for (i = 0; i < nr_pages; i++) {
701 #if BITS_PER_LONG < 64
702 struct xen_page_foreign *foreign;
704 foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
706 gnttab_free_pages(nr_pages, pages);
709 set_page_private(pages[i], (unsigned long)foreign);
711 SetPagePrivate(pages[i]);
716 EXPORT_SYMBOL(gnttab_alloc_pages);
719 * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
720 * @nr_pages; number of pages to free
723 void gnttab_free_pages(int nr_pages, struct page **pages)
727 for (i = 0; i < nr_pages; i++) {
728 if (PagePrivate(pages[i])) {
729 #if BITS_PER_LONG < 64
730 kfree((void *)page_private(pages[i]));
732 ClearPagePrivate(pages[i]);
735 free_xenballooned_pages(nr_pages, pages);
737 EXPORT_SYMBOL(gnttab_free_pages);
739 /* Handling of paged out grant targets (GNTST_eagain) */
740 #define MAX_DELAY 256
742 gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
748 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
749 if (*status == GNTST_eagain)
751 } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
753 if (delay >= MAX_DELAY) {
754 pr_err("%s: %s eagain grant\n", func, current->comm);
755 *status = GNTST_bad_page;
759 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
761 struct gnttab_map_grant_ref *op;
763 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
765 for (op = batch; op < batch + count; op++)
766 if (op->status == GNTST_eagain)
767 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
768 &op->status, __func__);
770 EXPORT_SYMBOL_GPL(gnttab_batch_map);
772 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
774 struct gnttab_copy *op;
776 if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
778 for (op = batch; op < batch + count; op++)
779 if (op->status == GNTST_eagain)
780 gnttab_retry_eagain_gop(GNTTABOP_copy, op,
781 &op->status, __func__);
783 EXPORT_SYMBOL_GPL(gnttab_batch_copy);
785 void gnttab_foreach_grant_in_range(struct page *page,
791 unsigned int goffset;
793 unsigned long xen_pfn;
795 len = min_t(unsigned int, PAGE_SIZE - offset, len);
796 goffset = xen_offset_in_page(offset);
798 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
801 glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
802 fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
809 EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
811 void gnttab_foreach_grant(struct page **pages,
812 unsigned int nr_grefs,
816 unsigned int goffset = 0;
817 unsigned long xen_pfn = 0;
820 for (i = 0; i < nr_grefs; i++) {
821 if ((i % XEN_PFN_PER_PAGE) == 0) {
822 xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
826 fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
828 goffset += XEN_PAGE_SIZE;
833 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
834 struct gnttab_map_grant_ref *kmap_ops,
835 struct page **pages, unsigned int count)
839 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
843 for (i = 0; i < count; i++) {
844 /* Retry eagain maps */
845 if (map_ops[i].status == GNTST_eagain)
846 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i,
847 &map_ops[i].status, __func__);
849 if (map_ops[i].status == GNTST_okay) {
850 struct xen_page_foreign *foreign;
852 SetPageForeign(pages[i]);
853 foreign = xen_page_foreign(pages[i]);
854 foreign->domid = map_ops[i].dom;
855 foreign->gref = map_ops[i].ref;
859 return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
861 EXPORT_SYMBOL_GPL(gnttab_map_refs);
863 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
864 struct gnttab_unmap_grant_ref *kunmap_ops,
865 struct page **pages, unsigned int count)
870 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
874 for (i = 0; i < count; i++)
875 ClearPageForeign(pages[i]);
877 return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
879 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
881 #define GNTTAB_UNMAP_REFS_DELAY 5
883 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
885 static void gnttab_unmap_work(struct work_struct *work)
887 struct gntab_unmap_queue_data
888 *unmap_data = container_of(work,
889 struct gntab_unmap_queue_data,
891 if (unmap_data->age != UINT_MAX)
893 __gnttab_unmap_refs_async(unmap_data);
896 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
901 for (pc = 0; pc < item->count; pc++) {
902 if (page_count(item->pages[pc]) > 1) {
903 unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
904 schedule_delayed_work(&item->gnttab_work,
905 msecs_to_jiffies(delay));
910 ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
911 item->pages, item->count);
912 item->done(ret, item);
915 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
917 INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
920 __gnttab_unmap_refs_async(item);
922 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
924 static void unmap_refs_callback(int result,
925 struct gntab_unmap_queue_data *data)
927 struct unmap_refs_callback_data *d = data->data;
930 complete(&d->completion);
933 int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
935 struct unmap_refs_callback_data data;
937 init_completion(&data.completion);
939 item->done = &unmap_refs_callback;
940 gnttab_unmap_refs_async(item);
941 wait_for_completion(&data.completion);
945 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
947 static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
951 rc = arch_gnttab_map_shared(frames, nr_gframes,
952 gnttab_max_grant_frames(),
953 &gnttab_shared.addr);
959 static void gnttab_unmap_frames_v1(void)
961 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
964 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
966 struct gnttab_setup_table setup;
968 unsigned int nr_gframes = end_idx + 1;
971 if (xen_feature(XENFEAT_auto_translated_physmap)) {
972 struct xen_add_to_physmap xatp;
973 unsigned int i = end_idx;
975 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
977 * Loop backwards, so that the first hypercall has the largest
978 * index, ensuring that the table will grow only once.
981 xatp.domid = DOMID_SELF;
983 xatp.space = XENMAPSPACE_grant_table;
984 xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
985 rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
987 pr_warn("grant table add_to_physmap failed, err=%d\n",
991 } while (i-- > start_idx);
996 /* No need for kzalloc as it is initialized in following hypercall
997 * GNTTABOP_setup_table.
999 frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC);
1003 setup.dom = DOMID_SELF;
1004 setup.nr_frames = nr_gframes;
1005 set_xen_guest_handle(setup.frame_list, frames);
1007 rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1008 if (rc == -ENOSYS) {
1013 BUG_ON(rc || setup.status);
1015 rc = gnttab_interface->map_frames(frames, nr_gframes);
1022 static const struct gnttab_ops gnttab_v1_ops = {
1023 .map_frames = gnttab_map_frames_v1,
1024 .unmap_frames = gnttab_unmap_frames_v1,
1025 .update_entry = gnttab_update_entry_v1,
1026 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v1,
1027 .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v1,
1028 .read_frame = gnttab_read_frame_v1,
1031 static void gnttab_request_version(void)
1033 /* Only version 1 is used, which will always be available. */
1034 grant_table_version = 1;
1035 grefs_per_grant_frame = XEN_PAGE_SIZE / sizeof(struct grant_entry_v1);
1036 gnttab_interface = &gnttab_v1_ops;
1038 pr_info("Grant tables using version %d layout\n", grant_table_version);
1041 static int gnttab_setup(void)
1043 unsigned int max_nr_gframes;
1045 max_nr_gframes = gnttab_max_grant_frames();
1046 if (max_nr_gframes < nr_grant_frames)
1049 if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1050 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1051 if (gnttab_shared.addr == NULL) {
1052 pr_warn("gnttab share frames (addr=0x%08lx) is not mapped!\n",
1053 (unsigned long)xen_auto_xlat_grant_frames.vaddr);
1057 return gnttab_map(0, nr_grant_frames - 1);
1060 int gnttab_resume(void)
1062 gnttab_request_version();
1063 return gnttab_setup();
1066 int gnttab_suspend(void)
1068 if (!xen_feature(XENFEAT_auto_translated_physmap))
1069 gnttab_interface->unmap_frames();
1073 static int gnttab_expand(unsigned int req_entries)
1076 unsigned int cur, extra;
1078 BUG_ON(grefs_per_grant_frame == 0);
1079 cur = nr_grant_frames;
1080 extra = ((req_entries + (grefs_per_grant_frame-1)) /
1081 grefs_per_grant_frame);
1082 if (cur + extra > gnttab_max_grant_frames())
1085 rc = gnttab_map(cur, cur + extra - 1);
1087 rc = grow_gnttab_list(extra);
1092 int gnttab_init(void)
1095 unsigned long max_nr_grant_frames;
1096 unsigned int max_nr_glist_frames, nr_glist_frames;
1097 unsigned int nr_init_grefs;
1100 gnttab_request_version();
1101 max_nr_grant_frames = gnttab_max_grant_frames();
1102 nr_grant_frames = 1;
1104 /* Determine the maximum number of frames required for the
1105 * grant reference free list on the current hypervisor.
1107 BUG_ON(grefs_per_grant_frame == 0);
1108 max_nr_glist_frames = (max_nr_grant_frames *
1109 grefs_per_grant_frame / RPP);
1111 gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *),
1113 if (gnttab_list == NULL)
1116 nr_glist_frames = (nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
1117 for (i = 0; i < nr_glist_frames; i++) {
1118 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1119 if (gnttab_list[i] == NULL) {
1125 ret = arch_gnttab_init(max_nr_grant_frames);
1129 if (gnttab_setup() < 0) {
1134 nr_init_grefs = nr_grant_frames * grefs_per_grant_frame;
1136 for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
1137 gnttab_entry(i) = i + 1;
1139 gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
1140 gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
1141 gnttab_free_head = NR_RESERVED_ENTRIES;
1143 printk("Grant table initialized\n");
1147 for (i--; i >= 0; i--)
1148 free_page((unsigned long)gnttab_list[i]);
1152 EXPORT_SYMBOL_GPL(gnttab_init);
1154 static int __gnttab_init(void)
1156 /* Delay grant-table initialization in the PV on HVM case */
1157 if (xen_hvm_domain())
1160 if (!xen_pv_domain())
1163 return gnttab_init();
1165 /* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1166 * beforehand to initialize xen_auto_xlat_grant_frames. */
1167 core_initcall_sync(__gnttab_init);