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/bitmap.h>
37 #include <linux/memblock.h>
38 #include <linux/sched.h>
40 #include <linux/slab.h>
41 #include <linux/vmalloc.h>
42 #include <linux/uaccess.h>
44 #include <linux/delay.h>
45 #include <linux/hardirq.h>
46 #include <linux/workqueue.h>
47 #include <linux/ratelimit.h>
48 #include <linux/moduleparam.h>
49 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
50 #include <linux/dma-mapping.h>
54 #include <xen/interface/xen.h>
56 #include <xen/grant_table.h>
57 #include <xen/interface/memory.h>
58 #include <xen/hvc-console.h>
59 #include <xen/swiotlb-xen.h>
60 #include <xen/balloon.h>
62 #include <asm/xen/cpuid.h>
64 #include <xen/mem-reservation.h>
65 #include <asm/xen/hypercall.h>
66 #include <asm/xen/interface.h>
68 #include <asm/sync_bitops.h>
70 #define GNTTAB_LIST_END 0xffffffff
72 static grant_ref_t **gnttab_list;
73 static unsigned int nr_grant_frames;
76 * Handling of free grants:
78 * Free grants are in a simple list anchored in gnttab_free_head. They are
79 * linked by grant ref, the last element contains GNTTAB_LIST_END. The number
80 * of free entries is stored in gnttab_free_count.
81 * Additionally there is a bitmap of free entries anchored in
82 * gnttab_free_bitmap. This is being used for simplifying allocation of
83 * multiple consecutive grants, which is needed e.g. for support of virtio.
84 * gnttab_last_free is used to add free entries of new frames at the end of
86 * gnttab_free_tail_ptr specifies the variable which references the start
87 * of consecutive free grants ending with gnttab_last_free. This pointer is
88 * updated in a rather defensive way, in order to avoid performance hits in
90 * All those variables are protected by gnttab_list_lock.
92 static int gnttab_free_count;
93 static unsigned int gnttab_size;
94 static grant_ref_t gnttab_free_head = GNTTAB_LIST_END;
95 static grant_ref_t gnttab_last_free = GNTTAB_LIST_END;
96 static grant_ref_t *gnttab_free_tail_ptr;
97 static unsigned long *gnttab_free_bitmap;
98 static DEFINE_SPINLOCK(gnttab_list_lock);
100 struct grant_frames xen_auto_xlat_grant_frames;
101 static unsigned int xen_gnttab_version;
102 module_param_named(version, xen_gnttab_version, uint, 0);
105 struct grant_entry_v1 *v1;
106 union grant_entry_v2 *v2;
110 /*This is a structure of function pointers for grant table*/
113 * Version of the grant interface.
115 unsigned int version;
117 * Grant refs per grant frame.
119 unsigned int grefs_per_grant_frame;
121 * Mapping a list of frames for storing grant entries. Frames parameter
122 * is used to store grant table address when grant table being setup,
123 * nr_gframes is the number of frames to map grant table. Returning
124 * GNTST_okay means success and negative value means failure.
126 int (*map_frames)(xen_pfn_t *frames, unsigned int nr_gframes);
128 * Release a list of frames which are mapped in map_frames for grant
131 void (*unmap_frames)(void);
133 * Introducing a valid entry into the grant table, granting the frame of
134 * this grant entry to domain for accessing. Ref
135 * parameter is reference of this introduced grant entry, domid is id of
136 * granted domain, frame is the page frame to be granted, and flags is
137 * status of the grant entry to be updated.
139 void (*update_entry)(grant_ref_t ref, domid_t domid,
140 unsigned long frame, unsigned flags);
142 * Stop granting a grant entry to domain for accessing. Ref parameter is
143 * reference of a grant entry whose grant access will be stopped.
144 * If the grant entry is currently mapped for reading or writing, just
145 * return failure(==0) directly and don't tear down the grant access.
146 * Otherwise, stop grant access for this entry and return success(==1).
148 int (*end_foreign_access_ref)(grant_ref_t ref);
150 * Read the frame number related to a given grant reference.
152 unsigned long (*read_frame)(grant_ref_t ref);
155 struct unmap_refs_callback_data {
156 struct completion completion;
160 static const struct gnttab_ops *gnttab_interface;
162 /* This reflects status of grant entries, so act as a global value. */
163 static grant_status_t *grstatus;
165 static struct gnttab_free_callback *gnttab_free_callback_list;
167 static int gnttab_expand(unsigned int req_entries);
169 #define RPP (PAGE_SIZE / sizeof(grant_ref_t))
170 #define SPP (PAGE_SIZE / sizeof(grant_status_t))
172 static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
174 return &gnttab_list[(entry) / RPP][(entry) % RPP];
176 /* This can be used as an l-value */
177 #define gnttab_entry(entry) (*__gnttab_entry(entry))
179 static int get_free_entries(unsigned count)
185 spin_lock_irqsave(&gnttab_list_lock, flags);
187 if ((gnttab_free_count < count) &&
188 ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
189 spin_unlock_irqrestore(&gnttab_list_lock, flags);
193 ref = head = gnttab_free_head;
194 gnttab_free_count -= count;
196 bitmap_clear(gnttab_free_bitmap, head, 1);
197 if (gnttab_free_tail_ptr == __gnttab_entry(head))
198 gnttab_free_tail_ptr = &gnttab_free_head;
200 head = gnttab_entry(head);
202 gnttab_free_head = gnttab_entry(head);
203 gnttab_entry(head) = GNTTAB_LIST_END;
205 if (!gnttab_free_count) {
206 gnttab_last_free = GNTTAB_LIST_END;
207 gnttab_free_tail_ptr = NULL;
210 spin_unlock_irqrestore(&gnttab_list_lock, flags);
215 static int get_seq_entry_count(void)
217 if (gnttab_last_free == GNTTAB_LIST_END || !gnttab_free_tail_ptr ||
218 *gnttab_free_tail_ptr == GNTTAB_LIST_END)
221 return gnttab_last_free - *gnttab_free_tail_ptr + 1;
224 /* Rebuilds the free grant list and tries to find count consecutive entries. */
225 static int get_free_seq(unsigned int count)
228 unsigned int from, to;
231 gnttab_free_tail_ptr = &gnttab_free_head;
232 last = &gnttab_free_head;
234 for (from = find_first_bit(gnttab_free_bitmap, gnttab_size);
236 from = find_next_bit(gnttab_free_bitmap, gnttab_size, to + 1)) {
237 to = find_next_zero_bit(gnttab_free_bitmap, gnttab_size,
239 if (ret < 0 && to - from >= count) {
241 bitmap_clear(gnttab_free_bitmap, ret, count);
243 gnttab_free_count -= count;
249 * Recreate the free list in order to have it properly sorted.
250 * This is needed to make sure that the free tail has the maximum
255 last = __gnttab_entry(from);
256 gnttab_last_free = from;
259 if (to < gnttab_size)
260 gnttab_free_tail_ptr = __gnttab_entry(to - 1);
263 *last = GNTTAB_LIST_END;
264 if (gnttab_last_free != gnttab_size - 1)
265 gnttab_free_tail_ptr = NULL;
270 static int get_free_entries_seq(unsigned int count)
275 spin_lock_irqsave(&gnttab_list_lock, flags);
277 if (gnttab_free_count < count) {
278 ret = gnttab_expand(count - gnttab_free_count);
283 if (get_seq_entry_count() < count) {
284 ret = get_free_seq(count);
287 ret = gnttab_expand(count - get_seq_entry_count());
292 ret = *gnttab_free_tail_ptr;
293 *gnttab_free_tail_ptr = gnttab_entry(ret + count - 1);
294 gnttab_free_count -= count;
295 if (!gnttab_free_count)
296 gnttab_free_tail_ptr = NULL;
297 bitmap_clear(gnttab_free_bitmap, ret, count);
300 spin_unlock_irqrestore(&gnttab_list_lock, flags);
305 static void do_free_callbacks(void)
307 struct gnttab_free_callback *callback, *next;
309 callback = gnttab_free_callback_list;
310 gnttab_free_callback_list = NULL;
312 while (callback != NULL) {
313 next = callback->next;
314 if (gnttab_free_count >= callback->count) {
315 callback->next = NULL;
316 callback->fn(callback->arg);
318 callback->next = gnttab_free_callback_list;
319 gnttab_free_callback_list = callback;
325 static inline void check_free_callbacks(void)
327 if (unlikely(gnttab_free_callback_list))
331 static void put_free_entry_locked(grant_ref_t ref)
333 if (unlikely(ref < GNTTAB_NR_RESERVED_ENTRIES))
336 gnttab_entry(ref) = gnttab_free_head;
337 gnttab_free_head = ref;
338 if (!gnttab_free_count)
339 gnttab_last_free = ref;
340 if (gnttab_free_tail_ptr == &gnttab_free_head)
341 gnttab_free_tail_ptr = __gnttab_entry(ref);
343 bitmap_set(gnttab_free_bitmap, ref, 1);
346 static void put_free_entry(grant_ref_t ref)
350 spin_lock_irqsave(&gnttab_list_lock, flags);
351 put_free_entry_locked(ref);
352 check_free_callbacks();
353 spin_unlock_irqrestore(&gnttab_list_lock, flags);
356 static void gnttab_set_free(unsigned int start, unsigned int n)
360 for (i = start; i < start + n - 1; i++)
361 gnttab_entry(i) = i + 1;
363 gnttab_entry(i) = GNTTAB_LIST_END;
364 if (!gnttab_free_count) {
365 gnttab_free_head = start;
366 gnttab_free_tail_ptr = &gnttab_free_head;
368 gnttab_entry(gnttab_last_free) = start;
370 gnttab_free_count += n;
371 gnttab_last_free = i;
373 bitmap_set(gnttab_free_bitmap, start, n);
377 * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
378 * Introducing a valid entry into the grant table:
379 * 1. Write ent->domid.
380 * 2. Write ent->frame: Frame to which access is permitted.
381 * 3. Write memory barrier (WMB).
382 * 4. Write ent->flags, inc. valid type.
384 static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
385 unsigned long frame, unsigned flags)
387 gnttab_shared.v1[ref].domid = domid;
388 gnttab_shared.v1[ref].frame = frame;
390 gnttab_shared.v1[ref].flags = flags;
393 static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
394 unsigned long frame, unsigned int flags)
396 gnttab_shared.v2[ref].hdr.domid = domid;
397 gnttab_shared.v2[ref].full_page.frame = frame;
398 wmb(); /* Hypervisor concurrent accesses. */
399 gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags;
403 * Public grant-issuing interface functions
405 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
406 unsigned long frame, int readonly)
408 gnttab_interface->update_entry(ref, domid, frame,
409 GTF_permit_access | (readonly ? GTF_readonly : 0));
411 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
413 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
418 ref = get_free_entries(1);
419 if (unlikely(ref < 0))
422 gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
426 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
428 static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref)
433 pflags = &gnttab_shared.v1[ref].flags;
437 if (flags & (GTF_reading|GTF_writing))
439 } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
444 static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref)
446 gnttab_shared.v2[ref].hdr.flags = 0;
447 mb(); /* Concurrent access by hypervisor. */
448 if (grstatus[ref] & (GTF_reading|GTF_writing)) {
452 * The read of grstatus needs to have acquire semantics.
453 * On x86, reads already have that, and we just need to
454 * protect against compiler reorderings.
455 * On other architectures we may need a full barrier.
467 static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref)
469 return gnttab_interface->end_foreign_access_ref(ref);
472 int gnttab_end_foreign_access_ref(grant_ref_t ref)
474 if (_gnttab_end_foreign_access_ref(ref))
476 pr_warn("WARNING: g.e. %#x still in use!\n", ref);
479 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
481 static unsigned long gnttab_read_frame_v1(grant_ref_t ref)
483 return gnttab_shared.v1[ref].frame;
486 static unsigned long gnttab_read_frame_v2(grant_ref_t ref)
488 return gnttab_shared.v2[ref].full_page.frame;
491 struct deferred_entry {
492 struct list_head list;
497 static LIST_HEAD(deferred_list);
498 static void gnttab_handle_deferred(struct timer_list *);
499 static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred);
501 static void gnttab_handle_deferred(struct timer_list *unused)
503 unsigned int nr = 10;
504 struct deferred_entry *first = NULL;
507 spin_lock_irqsave(&gnttab_list_lock, flags);
509 struct deferred_entry *entry
510 = list_first_entry(&deferred_list,
511 struct deferred_entry, list);
515 list_del(&entry->list);
516 spin_unlock_irqrestore(&gnttab_list_lock, flags);
517 if (_gnttab_end_foreign_access_ref(entry->ref)) {
518 put_free_entry(entry->ref);
519 pr_debug("freeing g.e. %#x (pfn %#lx)\n",
520 entry->ref, page_to_pfn(entry->page));
521 put_page(entry->page);
525 if (!--entry->warn_delay)
526 pr_info("g.e. %#x still pending\n", entry->ref);
530 spin_lock_irqsave(&gnttab_list_lock, flags);
532 list_add_tail(&entry->list, &deferred_list);
533 else if (list_empty(&deferred_list))
536 if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
537 deferred_timer.expires = jiffies + HZ;
538 add_timer(&deferred_timer);
540 spin_unlock_irqrestore(&gnttab_list_lock, flags);
543 static void gnttab_add_deferred(grant_ref_t ref, struct page *page)
545 struct deferred_entry *entry;
546 gfp_t gfp = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
547 const char *what = KERN_WARNING "leaking";
549 entry = kmalloc(sizeof(*entry), gfp);
551 unsigned long gfn = gnttab_interface->read_frame(ref);
553 page = pfn_to_page(gfn_to_pfn(gfn));
562 entry->warn_delay = 60;
563 spin_lock_irqsave(&gnttab_list_lock, flags);
564 list_add_tail(&entry->list, &deferred_list);
565 if (!timer_pending(&deferred_timer)) {
566 deferred_timer.expires = jiffies + HZ;
567 add_timer(&deferred_timer);
569 spin_unlock_irqrestore(&gnttab_list_lock, flags);
570 what = KERN_DEBUG "deferring";
572 printk("%s g.e. %#x (pfn %#lx)\n",
573 what, ref, page ? page_to_pfn(page) : -1);
576 int gnttab_try_end_foreign_access(grant_ref_t ref)
578 int ret = _gnttab_end_foreign_access_ref(ref);
585 EXPORT_SYMBOL_GPL(gnttab_try_end_foreign_access);
587 void gnttab_end_foreign_access(grant_ref_t ref, struct page *page)
589 if (gnttab_try_end_foreign_access(ref)) {
593 gnttab_add_deferred(ref, page);
595 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
597 void gnttab_free_grant_reference(grant_ref_t ref)
601 EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
603 void gnttab_free_grant_references(grant_ref_t head)
608 spin_lock_irqsave(&gnttab_list_lock, flags);
609 while (head != GNTTAB_LIST_END) {
610 ref = gnttab_entry(head);
611 put_free_entry_locked(head);
614 check_free_callbacks();
615 spin_unlock_irqrestore(&gnttab_list_lock, flags);
617 EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
619 void gnttab_free_grant_reference_seq(grant_ref_t head, unsigned int count)
624 spin_lock_irqsave(&gnttab_list_lock, flags);
625 for (i = count; i > 0; i--)
626 put_free_entry_locked(head + i - 1);
627 check_free_callbacks();
628 spin_unlock_irqrestore(&gnttab_list_lock, flags);
630 EXPORT_SYMBOL_GPL(gnttab_free_grant_reference_seq);
632 int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
634 int h = get_free_entries(count);
643 EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
645 int gnttab_alloc_grant_reference_seq(unsigned int count, grant_ref_t *first)
650 h = get_free_entries(1);
652 h = get_free_entries_seq(count);
661 EXPORT_SYMBOL_GPL(gnttab_alloc_grant_reference_seq);
663 int gnttab_empty_grant_references(const grant_ref_t *private_head)
665 return (*private_head == GNTTAB_LIST_END);
667 EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
669 int gnttab_claim_grant_reference(grant_ref_t *private_head)
671 grant_ref_t g = *private_head;
672 if (unlikely(g == GNTTAB_LIST_END))
674 *private_head = gnttab_entry(g);
677 EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
679 void gnttab_release_grant_reference(grant_ref_t *private_head,
682 gnttab_entry(release) = *private_head;
683 *private_head = release;
685 EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
687 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
688 void (*fn)(void *), void *arg, u16 count)
691 struct gnttab_free_callback *cb;
693 spin_lock_irqsave(&gnttab_list_lock, flags);
695 /* Check if the callback is already on the list */
696 cb = gnttab_free_callback_list;
705 callback->count = count;
706 callback->next = gnttab_free_callback_list;
707 gnttab_free_callback_list = callback;
708 check_free_callbacks();
710 spin_unlock_irqrestore(&gnttab_list_lock, flags);
712 EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
714 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
716 struct gnttab_free_callback **pcb;
719 spin_lock_irqsave(&gnttab_list_lock, flags);
720 for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
721 if (*pcb == callback) {
722 *pcb = callback->next;
726 spin_unlock_irqrestore(&gnttab_list_lock, flags);
728 EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
730 static unsigned int gnttab_frames(unsigned int frames, unsigned int align)
732 return (frames * gnttab_interface->grefs_per_grant_frame + align - 1) /
736 static int grow_gnttab_list(unsigned int more_frames)
738 unsigned int new_nr_grant_frames, extra_entries, i;
739 unsigned int nr_glist_frames, new_nr_glist_frames;
740 unsigned int grefs_per_frame;
742 grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
744 new_nr_grant_frames = nr_grant_frames + more_frames;
745 extra_entries = more_frames * grefs_per_frame;
747 nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
748 new_nr_glist_frames = gnttab_frames(new_nr_grant_frames, RPP);
749 for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
750 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
755 gnttab_set_free(gnttab_size, extra_entries);
757 if (!gnttab_free_tail_ptr)
758 gnttab_free_tail_ptr = __gnttab_entry(gnttab_size);
760 nr_grant_frames = new_nr_grant_frames;
761 gnttab_size += extra_entries;
763 check_free_callbacks();
768 while (i-- > nr_glist_frames)
769 free_page((unsigned long) gnttab_list[i]);
773 static unsigned int __max_nr_grant_frames(void)
775 struct gnttab_query_size query;
778 query.dom = DOMID_SELF;
780 rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
781 if ((rc < 0) || (query.status != GNTST_okay))
782 return 4; /* Legacy max supported number of frames */
784 return query.max_nr_frames;
787 unsigned int gnttab_max_grant_frames(void)
789 unsigned int xen_max = __max_nr_grant_frames();
790 static unsigned int boot_max_nr_grant_frames;
792 /* First time, initialize it properly. */
793 if (!boot_max_nr_grant_frames)
794 boot_max_nr_grant_frames = __max_nr_grant_frames();
796 if (xen_max > boot_max_nr_grant_frames)
797 return boot_max_nr_grant_frames;
800 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
802 int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
805 unsigned int max_nr_gframes = __max_nr_grant_frames();
809 if (xen_auto_xlat_grant_frames.count)
812 vaddr = memremap(addr, XEN_PAGE_SIZE * max_nr_gframes, MEMREMAP_WB);
814 pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
818 pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
823 for (i = 0; i < max_nr_gframes; i++)
824 pfn[i] = XEN_PFN_DOWN(addr) + i;
826 xen_auto_xlat_grant_frames.vaddr = vaddr;
827 xen_auto_xlat_grant_frames.pfn = pfn;
828 xen_auto_xlat_grant_frames.count = max_nr_gframes;
832 EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
834 void gnttab_free_auto_xlat_frames(void)
836 if (!xen_auto_xlat_grant_frames.count)
838 kfree(xen_auto_xlat_grant_frames.pfn);
839 memunmap(xen_auto_xlat_grant_frames.vaddr);
841 xen_auto_xlat_grant_frames.pfn = NULL;
842 xen_auto_xlat_grant_frames.count = 0;
843 xen_auto_xlat_grant_frames.vaddr = NULL;
845 EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
847 int gnttab_pages_set_private(int nr_pages, struct page **pages)
851 for (i = 0; i < nr_pages; i++) {
852 #if BITS_PER_LONG < 64
853 struct xen_page_foreign *foreign;
855 foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
859 set_page_private(pages[i], (unsigned long)foreign);
861 SetPagePrivate(pages[i]);
866 EXPORT_SYMBOL_GPL(gnttab_pages_set_private);
869 * gnttab_alloc_pages - alloc pages suitable for grant mapping into
870 * @nr_pages: number of pages to alloc
871 * @pages: returns the pages
873 int gnttab_alloc_pages(int nr_pages, struct page **pages)
877 ret = xen_alloc_unpopulated_pages(nr_pages, pages);
881 ret = gnttab_pages_set_private(nr_pages, pages);
883 gnttab_free_pages(nr_pages, pages);
887 EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
889 #ifdef CONFIG_XEN_UNPOPULATED_ALLOC
890 static inline void cache_init(struct gnttab_page_cache *cache)
895 static inline bool cache_empty(struct gnttab_page_cache *cache)
897 return !cache->pages;
900 static inline struct page *cache_deq(struct gnttab_page_cache *cache)
905 cache->pages = page->zone_device_data;
910 static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
912 page->zone_device_data = cache->pages;
916 static inline void cache_init(struct gnttab_page_cache *cache)
918 INIT_LIST_HEAD(&cache->pages);
921 static inline bool cache_empty(struct gnttab_page_cache *cache)
923 return list_empty(&cache->pages);
926 static inline struct page *cache_deq(struct gnttab_page_cache *cache)
930 page = list_first_entry(&cache->pages, struct page, lru);
931 list_del(&page->lru);
936 static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
938 list_add(&page->lru, &cache->pages);
942 void gnttab_page_cache_init(struct gnttab_page_cache *cache)
944 spin_lock_init(&cache->lock);
946 cache->num_pages = 0;
948 EXPORT_SYMBOL_GPL(gnttab_page_cache_init);
950 int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page)
954 spin_lock_irqsave(&cache->lock, flags);
956 if (cache_empty(cache)) {
957 spin_unlock_irqrestore(&cache->lock, flags);
958 return gnttab_alloc_pages(1, page);
961 page[0] = cache_deq(cache);
964 spin_unlock_irqrestore(&cache->lock, flags);
968 EXPORT_SYMBOL_GPL(gnttab_page_cache_get);
970 void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
976 spin_lock_irqsave(&cache->lock, flags);
978 for (i = 0; i < num; i++)
979 cache_enq(cache, page[i]);
980 cache->num_pages += num;
982 spin_unlock_irqrestore(&cache->lock, flags);
984 EXPORT_SYMBOL_GPL(gnttab_page_cache_put);
986 void gnttab_page_cache_shrink(struct gnttab_page_cache *cache, unsigned int num)
988 struct page *page[10];
992 spin_lock_irqsave(&cache->lock, flags);
994 while (cache->num_pages > num) {
995 page[i] = cache_deq(cache);
997 if (++i == ARRAY_SIZE(page)) {
998 spin_unlock_irqrestore(&cache->lock, flags);
999 gnttab_free_pages(i, page);
1001 spin_lock_irqsave(&cache->lock, flags);
1005 spin_unlock_irqrestore(&cache->lock, flags);
1008 gnttab_free_pages(i, page);
1010 EXPORT_SYMBOL_GPL(gnttab_page_cache_shrink);
1012 void gnttab_pages_clear_private(int nr_pages, struct page **pages)
1016 for (i = 0; i < nr_pages; i++) {
1017 if (PagePrivate(pages[i])) {
1018 #if BITS_PER_LONG < 64
1019 kfree((void *)page_private(pages[i]));
1021 ClearPagePrivate(pages[i]);
1025 EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);
1028 * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
1029 * @nr_pages; number of pages to free
1032 void gnttab_free_pages(int nr_pages, struct page **pages)
1034 gnttab_pages_clear_private(nr_pages, pages);
1035 xen_free_unpopulated_pages(nr_pages, pages);
1037 EXPORT_SYMBOL_GPL(gnttab_free_pages);
1039 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
1041 * gnttab_dma_alloc_pages - alloc DMAable pages suitable for grant mapping into
1042 * @args: arguments to the function
1044 int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args)
1046 unsigned long pfn, start_pfn;
1050 if (args->nr_pages < 0 || args->nr_pages > (INT_MAX >> PAGE_SHIFT))
1053 size = args->nr_pages << PAGE_SHIFT;
1055 args->vaddr = dma_alloc_coherent(args->dev, size,
1056 &args->dev_bus_addr,
1057 GFP_KERNEL | __GFP_NOWARN);
1059 args->vaddr = dma_alloc_wc(args->dev, size,
1060 &args->dev_bus_addr,
1061 GFP_KERNEL | __GFP_NOWARN);
1063 pr_debug("Failed to allocate DMA buffer of size %zu\n", size);
1067 start_pfn = __phys_to_pfn(args->dev_bus_addr);
1068 for (pfn = start_pfn, i = 0; pfn < start_pfn + args->nr_pages;
1070 struct page *page = pfn_to_page(pfn);
1072 args->pages[i] = page;
1073 args->frames[i] = xen_page_to_gfn(page);
1074 xenmem_reservation_scrub_page(page);
1077 xenmem_reservation_va_mapping_reset(args->nr_pages, args->pages);
1079 ret = xenmem_reservation_decrease(args->nr_pages, args->frames);
1080 if (ret != args->nr_pages) {
1081 pr_debug("Failed to decrease reservation for DMA buffer\n");
1086 ret = gnttab_pages_set_private(args->nr_pages, args->pages);
1093 gnttab_dma_free_pages(args);
1096 EXPORT_SYMBOL_GPL(gnttab_dma_alloc_pages);
1099 * gnttab_dma_free_pages - free DMAable pages
1100 * @args: arguments to the function
1102 int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args)
1107 gnttab_pages_clear_private(args->nr_pages, args->pages);
1109 for (i = 0; i < args->nr_pages; i++)
1110 args->frames[i] = page_to_xen_pfn(args->pages[i]);
1112 ret = xenmem_reservation_increase(args->nr_pages, args->frames);
1113 if (ret != args->nr_pages) {
1114 pr_debug("Failed to increase reservation for DMA buffer\n");
1120 xenmem_reservation_va_mapping_update(args->nr_pages, args->pages,
1123 size = args->nr_pages << PAGE_SHIFT;
1125 dma_free_coherent(args->dev, size,
1126 args->vaddr, args->dev_bus_addr);
1128 dma_free_wc(args->dev, size,
1129 args->vaddr, args->dev_bus_addr);
1132 EXPORT_SYMBOL_GPL(gnttab_dma_free_pages);
1135 /* Handling of paged out grant targets (GNTST_eagain) */
1136 #define MAX_DELAY 256
1138 gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
1144 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
1145 if (*status == GNTST_eagain)
1147 } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
1149 if (delay >= MAX_DELAY) {
1150 pr_err("%s: %s eagain grant\n", func, current->comm);
1151 *status = GNTST_bad_page;
1155 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
1157 struct gnttab_map_grant_ref *op;
1159 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
1161 for (op = batch; op < batch + count; op++)
1162 if (op->status == GNTST_eagain)
1163 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
1164 &op->status, __func__);
1166 EXPORT_SYMBOL_GPL(gnttab_batch_map);
1168 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
1170 struct gnttab_copy *op;
1172 if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
1174 for (op = batch; op < batch + count; op++)
1175 if (op->status == GNTST_eagain)
1176 gnttab_retry_eagain_gop(GNTTABOP_copy, op,
1177 &op->status, __func__);
1179 EXPORT_SYMBOL_GPL(gnttab_batch_copy);
1181 void gnttab_foreach_grant_in_range(struct page *page,
1182 unsigned int offset,
1187 unsigned int goffset;
1189 unsigned long xen_pfn;
1191 len = min_t(unsigned int, PAGE_SIZE - offset, len);
1192 goffset = xen_offset_in_page(offset);
1194 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
1197 glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
1198 fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
1205 EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
1207 void gnttab_foreach_grant(struct page **pages,
1208 unsigned int nr_grefs,
1212 unsigned int goffset = 0;
1213 unsigned long xen_pfn = 0;
1216 for (i = 0; i < nr_grefs; i++) {
1217 if ((i % XEN_PFN_PER_PAGE) == 0) {
1218 xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
1222 fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
1224 goffset += XEN_PAGE_SIZE;
1229 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
1230 struct gnttab_map_grant_ref *kmap_ops,
1231 struct page **pages, unsigned int count)
1235 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
1239 for (i = 0; i < count; i++) {
1240 switch (map_ops[i].status) {
1243 struct xen_page_foreign *foreign;
1245 SetPageForeign(pages[i]);
1246 foreign = xen_page_foreign(pages[i]);
1247 foreign->domid = map_ops[i].dom;
1248 foreign->gref = map_ops[i].ref;
1252 case GNTST_no_device_space:
1253 pr_warn_ratelimited("maptrack limit reached, can't map all guest pages\n");
1257 /* Retry eagain maps */
1258 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref,
1260 &map_ops[i].status, __func__);
1261 /* Test status in next loop iteration. */
1270 return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
1272 EXPORT_SYMBOL_GPL(gnttab_map_refs);
1274 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
1275 struct gnttab_unmap_grant_ref *kunmap_ops,
1276 struct page **pages, unsigned int count)
1281 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
1285 for (i = 0; i < count; i++)
1286 ClearPageForeign(pages[i]);
1288 return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
1290 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
1292 #define GNTTAB_UNMAP_REFS_DELAY 5
1294 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
1296 static void gnttab_unmap_work(struct work_struct *work)
1298 struct gntab_unmap_queue_data
1299 *unmap_data = container_of(work,
1300 struct gntab_unmap_queue_data,
1302 if (unmap_data->age != UINT_MAX)
1304 __gnttab_unmap_refs_async(unmap_data);
1307 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1312 for (pc = 0; pc < item->count; pc++) {
1313 if (page_count(item->pages[pc]) > 1) {
1314 unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
1315 schedule_delayed_work(&item->gnttab_work,
1316 msecs_to_jiffies(delay));
1321 ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
1322 item->pages, item->count);
1323 item->done(ret, item);
1326 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1328 INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
1331 __gnttab_unmap_refs_async(item);
1333 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
1335 static void unmap_refs_callback(int result,
1336 struct gntab_unmap_queue_data *data)
1338 struct unmap_refs_callback_data *d = data->data;
1341 complete(&d->completion);
1344 int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
1346 struct unmap_refs_callback_data data;
1348 init_completion(&data.completion);
1350 item->done = &unmap_refs_callback;
1351 gnttab_unmap_refs_async(item);
1352 wait_for_completion(&data.completion);
1356 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
1358 static unsigned int nr_status_frames(unsigned int nr_grant_frames)
1360 return gnttab_frames(nr_grant_frames, SPP);
1363 static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
1367 rc = arch_gnttab_map_shared(frames, nr_gframes,
1368 gnttab_max_grant_frames(),
1369 &gnttab_shared.addr);
1375 static void gnttab_unmap_frames_v1(void)
1377 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1380 static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
1383 unsigned int nr_sframes;
1384 struct gnttab_get_status_frames getframes;
1387 nr_sframes = nr_status_frames(nr_gframes);
1389 /* No need for kzalloc as it is initialized in following hypercall
1390 * GNTTABOP_get_status_frames.
1392 sframes = kmalloc_array(nr_sframes, sizeof(uint64_t), GFP_ATOMIC);
1396 getframes.dom = DOMID_SELF;
1397 getframes.nr_frames = nr_sframes;
1398 set_xen_guest_handle(getframes.frame_list, sframes);
1400 rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
1402 if (rc == -ENOSYS) {
1407 BUG_ON(rc || getframes.status);
1409 rc = arch_gnttab_map_status(sframes, nr_sframes,
1410 nr_status_frames(gnttab_max_grant_frames()),
1415 rc = arch_gnttab_map_shared(frames, nr_gframes,
1416 gnttab_max_grant_frames(),
1417 &gnttab_shared.addr);
1423 static void gnttab_unmap_frames_v2(void)
1425 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1426 arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
1429 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
1431 struct gnttab_setup_table setup;
1433 unsigned int nr_gframes = end_idx + 1;
1436 if (xen_feature(XENFEAT_auto_translated_physmap)) {
1437 struct xen_add_to_physmap xatp;
1438 unsigned int i = end_idx;
1440 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
1442 * Loop backwards, so that the first hypercall has the largest
1443 * index, ensuring that the table will grow only once.
1446 xatp.domid = DOMID_SELF;
1448 xatp.space = XENMAPSPACE_grant_table;
1449 xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
1450 rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
1452 pr_warn("grant table add_to_physmap failed, err=%d\n",
1456 } while (i-- > start_idx);
1461 /* No need for kzalloc as it is initialized in following hypercall
1462 * GNTTABOP_setup_table.
1464 frames = kmalloc_array(nr_gframes, sizeof(unsigned long), GFP_ATOMIC);
1468 setup.dom = DOMID_SELF;
1469 setup.nr_frames = nr_gframes;
1470 set_xen_guest_handle(setup.frame_list, frames);
1472 rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1473 if (rc == -ENOSYS) {
1478 BUG_ON(rc || setup.status);
1480 rc = gnttab_interface->map_frames(frames, nr_gframes);
1487 static const struct gnttab_ops gnttab_v1_ops = {
1489 .grefs_per_grant_frame = XEN_PAGE_SIZE /
1490 sizeof(struct grant_entry_v1),
1491 .map_frames = gnttab_map_frames_v1,
1492 .unmap_frames = gnttab_unmap_frames_v1,
1493 .update_entry = gnttab_update_entry_v1,
1494 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v1,
1495 .read_frame = gnttab_read_frame_v1,
1498 static const struct gnttab_ops gnttab_v2_ops = {
1500 .grefs_per_grant_frame = XEN_PAGE_SIZE /
1501 sizeof(union grant_entry_v2),
1502 .map_frames = gnttab_map_frames_v2,
1503 .unmap_frames = gnttab_unmap_frames_v2,
1504 .update_entry = gnttab_update_entry_v2,
1505 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v2,
1506 .read_frame = gnttab_read_frame_v2,
1509 static bool gnttab_need_v2(void)
1512 uint32_t base, width;
1514 if (xen_pv_domain()) {
1515 base = xen_cpuid_base();
1516 if (cpuid_eax(base) < 5)
1517 return false; /* Information not available, use V1. */
1518 width = cpuid_ebx(base + 5) &
1519 XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
1520 return width > 32 + PAGE_SHIFT;
1523 return !!(max_possible_pfn >> 32);
1526 static void gnttab_request_version(void)
1529 struct gnttab_set_version gsv;
1531 if (gnttab_need_v2())
1536 /* Boot parameter overrides automatic selection. */
1537 if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
1538 gsv.version = xen_gnttab_version;
1540 rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1541 if (rc == 0 && gsv.version == 2)
1542 gnttab_interface = &gnttab_v2_ops;
1544 gnttab_interface = &gnttab_v1_ops;
1545 pr_info("Grant tables using version %d layout\n",
1546 gnttab_interface->version);
1549 static int gnttab_setup(void)
1551 unsigned int max_nr_gframes;
1553 max_nr_gframes = gnttab_max_grant_frames();
1554 if (max_nr_gframes < nr_grant_frames)
1557 if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1558 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1559 if (gnttab_shared.addr == NULL) {
1560 pr_warn("gnttab share frames is not mapped!\n");
1564 return gnttab_map(0, nr_grant_frames - 1);
1567 int gnttab_resume(void)
1569 gnttab_request_version();
1570 return gnttab_setup();
1573 int gnttab_suspend(void)
1575 if (!xen_feature(XENFEAT_auto_translated_physmap))
1576 gnttab_interface->unmap_frames();
1580 static int gnttab_expand(unsigned int req_entries)
1583 unsigned int cur, extra;
1585 cur = nr_grant_frames;
1586 extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
1587 gnttab_interface->grefs_per_grant_frame);
1588 if (cur + extra > gnttab_max_grant_frames()) {
1589 pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
1590 " cur=%u extra=%u limit=%u"
1591 " gnttab_free_count=%u req_entries=%u\n",
1592 cur, extra, gnttab_max_grant_frames(),
1593 gnttab_free_count, req_entries);
1597 rc = gnttab_map(cur, cur + extra - 1);
1599 rc = grow_gnttab_list(extra);
1604 int gnttab_init(void)
1607 unsigned long max_nr_grant_frames, max_nr_grefs;
1608 unsigned int max_nr_glist_frames, nr_glist_frames;
1611 gnttab_request_version();
1612 max_nr_grant_frames = gnttab_max_grant_frames();
1613 max_nr_grefs = max_nr_grant_frames *
1614 gnttab_interface->grefs_per_grant_frame;
1615 nr_grant_frames = 1;
1617 /* Determine the maximum number of frames required for the
1618 * grant reference free list on the current hypervisor.
1620 max_nr_glist_frames = max_nr_grefs / RPP;
1622 gnttab_list = kmalloc_array(max_nr_glist_frames,
1623 sizeof(grant_ref_t *),
1625 if (gnttab_list == NULL)
1628 nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
1629 for (i = 0; i < nr_glist_frames; i++) {
1630 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1631 if (gnttab_list[i] == NULL) {
1637 gnttab_free_bitmap = bitmap_zalloc(max_nr_grefs, GFP_KERNEL);
1638 if (!gnttab_free_bitmap) {
1643 ret = arch_gnttab_init(max_nr_grant_frames,
1644 nr_status_frames(max_nr_grant_frames));
1648 if (gnttab_setup() < 0) {
1653 gnttab_size = nr_grant_frames * gnttab_interface->grefs_per_grant_frame;
1655 gnttab_set_free(GNTTAB_NR_RESERVED_ENTRIES,
1656 gnttab_size - GNTTAB_NR_RESERVED_ENTRIES);
1658 printk("Grant table initialized\n");
1662 for (i--; i >= 0; i--)
1663 free_page((unsigned long)gnttab_list[i]);
1665 bitmap_free(gnttab_free_bitmap);
1668 EXPORT_SYMBOL_GPL(gnttab_init);
1670 static int __gnttab_init(void)
1675 /* Delay grant-table initialization in the PV on HVM case */
1676 if (xen_hvm_domain() && !xen_pvh_domain())
1679 return gnttab_init();
1681 /* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1682 * beforehand to initialize xen_auto_xlat_grant_frames. */
1683 core_initcall_sync(__gnttab_init);