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/memblock.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>
46 #include <linux/ratelimit.h>
47 #include <linux/moduleparam.h>
48 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
49 #include <linux/dma-mapping.h>
53 #include <xen/interface/xen.h>
55 #include <xen/grant_table.h>
56 #include <xen/interface/memory.h>
57 #include <xen/hvc-console.h>
58 #include <xen/swiotlb-xen.h>
59 #include <xen/balloon.h>
61 #include <asm/xen/cpuid.h>
63 #include <xen/mem-reservation.h>
64 #include <asm/xen/hypercall.h>
65 #include <asm/xen/interface.h>
67 #include <asm/pgtable.h>
68 #include <asm/sync_bitops.h>
70 /* External tools reserve first few grant table entries. */
71 #define NR_RESERVED_ENTRIES 8
72 #define GNTTAB_LIST_END 0xffffffff
74 static grant_ref_t **gnttab_list;
75 static unsigned int nr_grant_frames;
76 static int gnttab_free_count;
77 static grant_ref_t gnttab_free_head;
78 static DEFINE_SPINLOCK(gnttab_list_lock);
79 struct grant_frames xen_auto_xlat_grant_frames;
80 static unsigned int xen_gnttab_version;
81 module_param_named(version, xen_gnttab_version, uint, 0);
84 struct grant_entry_v1 *v1;
85 union grant_entry_v2 *v2;
89 /*This is a structure of function pointers for grant table*/
92 * Version of the grant interface.
96 * Grant refs per grant frame.
98 unsigned int grefs_per_grant_frame;
100 * Mapping a list of frames for storing grant entries. Frames parameter
101 * is used to store grant table address when grant table being setup,
102 * nr_gframes is the number of frames to map grant table. Returning
103 * GNTST_okay means success and negative value means failure.
105 int (*map_frames)(xen_pfn_t *frames, unsigned int nr_gframes);
107 * Release a list of frames which are mapped in map_frames for grant
110 void (*unmap_frames)(void);
112 * Introducing a valid entry into the grant table, granting the frame of
113 * this grant entry to domain for accessing or transfering. Ref
114 * parameter is reference of this introduced grant entry, domid is id of
115 * granted domain, frame is the page frame to be granted, and flags is
116 * status of the grant entry to be updated.
118 void (*update_entry)(grant_ref_t ref, domid_t domid,
119 unsigned long frame, unsigned flags);
121 * Stop granting a grant entry to domain for accessing. Ref parameter is
122 * reference of a grant entry whose grant access will be stopped,
123 * readonly is not in use in this function. If the grant entry is
124 * currently mapped for reading or writing, just return failure(==0)
125 * directly and don't tear down the grant access. Otherwise, stop grant
126 * access for this entry and return success(==1).
128 int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);
130 * Stop granting a grant entry to domain for transfer. Ref parameter is
131 * reference of a grant entry whose grant transfer will be stopped. If
132 * tranfer has not started, just reclaim the grant entry and return
133 * failure(==0). Otherwise, wait for the transfer to complete and then
136 unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
138 * Query the status of a grant entry. Ref parameter is reference of
139 * queried grant entry, return value is the status of queried entry.
140 * Detailed status(writing/reading) can be gotten from the return value
143 int (*query_foreign_access)(grant_ref_t ref);
146 struct unmap_refs_callback_data {
147 struct completion completion;
151 static const struct gnttab_ops *gnttab_interface;
153 /* This reflects status of grant entries, so act as a global value. */
154 static grant_status_t *grstatus;
156 static struct gnttab_free_callback *gnttab_free_callback_list;
158 static int gnttab_expand(unsigned int req_entries);
160 #define RPP (PAGE_SIZE / sizeof(grant_ref_t))
161 #define SPP (PAGE_SIZE / sizeof(grant_status_t))
163 static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
165 return &gnttab_list[(entry) / RPP][(entry) % RPP];
167 /* This can be used as an l-value */
168 #define gnttab_entry(entry) (*__gnttab_entry(entry))
170 static int get_free_entries(unsigned count)
176 spin_lock_irqsave(&gnttab_list_lock, flags);
178 if ((gnttab_free_count < count) &&
179 ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
180 spin_unlock_irqrestore(&gnttab_list_lock, flags);
184 ref = head = gnttab_free_head;
185 gnttab_free_count -= count;
187 head = gnttab_entry(head);
188 gnttab_free_head = gnttab_entry(head);
189 gnttab_entry(head) = GNTTAB_LIST_END;
191 spin_unlock_irqrestore(&gnttab_list_lock, flags);
196 static void do_free_callbacks(void)
198 struct gnttab_free_callback *callback, *next;
200 callback = gnttab_free_callback_list;
201 gnttab_free_callback_list = NULL;
203 while (callback != NULL) {
204 next = callback->next;
205 if (gnttab_free_count >= callback->count) {
206 callback->next = NULL;
207 callback->fn(callback->arg);
209 callback->next = gnttab_free_callback_list;
210 gnttab_free_callback_list = callback;
216 static inline void check_free_callbacks(void)
218 if (unlikely(gnttab_free_callback_list))
222 static void put_free_entry(grant_ref_t ref)
225 spin_lock_irqsave(&gnttab_list_lock, flags);
226 gnttab_entry(ref) = gnttab_free_head;
227 gnttab_free_head = ref;
229 check_free_callbacks();
230 spin_unlock_irqrestore(&gnttab_list_lock, flags);
234 * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
235 * Introducing a valid entry into the grant table:
236 * 1. Write ent->domid.
237 * 2. Write ent->frame:
238 * GTF_permit_access: Frame to which access is permitted.
239 * GTF_accept_transfer: Pseudo-phys frame slot being filled by new
240 * frame, or zero if none.
241 * 3. Write memory barrier (WMB).
242 * 4. Write ent->flags, inc. valid type.
244 static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
245 unsigned long frame, unsigned flags)
247 gnttab_shared.v1[ref].domid = domid;
248 gnttab_shared.v1[ref].frame = frame;
250 gnttab_shared.v1[ref].flags = flags;
253 static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
254 unsigned long frame, unsigned int flags)
256 gnttab_shared.v2[ref].hdr.domid = domid;
257 gnttab_shared.v2[ref].full_page.frame = frame;
258 wmb(); /* Hypervisor concurrent accesses. */
259 gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags;
263 * Public grant-issuing interface functions
265 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
266 unsigned long frame, int readonly)
268 gnttab_interface->update_entry(ref, domid, frame,
269 GTF_permit_access | (readonly ? GTF_readonly : 0));
271 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
273 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
278 ref = get_free_entries(1);
279 if (unlikely(ref < 0))
282 gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
286 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
288 static int gnttab_query_foreign_access_v1(grant_ref_t ref)
290 return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
293 static int gnttab_query_foreign_access_v2(grant_ref_t ref)
295 return grstatus[ref] & (GTF_reading|GTF_writing);
298 int gnttab_query_foreign_access(grant_ref_t ref)
300 return gnttab_interface->query_foreign_access(ref);
302 EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
304 static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
309 pflags = &gnttab_shared.v1[ref].flags;
313 if (flags & (GTF_reading|GTF_writing))
315 } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
320 static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly)
322 gnttab_shared.v2[ref].hdr.flags = 0;
323 mb(); /* Concurrent access by hypervisor. */
324 if (grstatus[ref] & (GTF_reading|GTF_writing)) {
328 * The read of grstatus needs to have acquire semantics.
329 * On x86, reads already have that, and we just need to
330 * protect against compiler reorderings.
331 * On other architectures we may need a full barrier.
343 static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
345 return gnttab_interface->end_foreign_access_ref(ref, readonly);
348 int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
350 if (_gnttab_end_foreign_access_ref(ref, readonly))
352 pr_warn("WARNING: g.e. %#x still in use!\n", ref);
355 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
357 struct deferred_entry {
358 struct list_head list;
364 static LIST_HEAD(deferred_list);
365 static void gnttab_handle_deferred(struct timer_list *);
366 static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred);
368 static void gnttab_handle_deferred(struct timer_list *unused)
370 unsigned int nr = 10;
371 struct deferred_entry *first = NULL;
374 spin_lock_irqsave(&gnttab_list_lock, flags);
376 struct deferred_entry *entry
377 = list_first_entry(&deferred_list,
378 struct deferred_entry, list);
382 list_del(&entry->list);
383 spin_unlock_irqrestore(&gnttab_list_lock, flags);
384 if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
385 put_free_entry(entry->ref);
387 pr_debug("freeing g.e. %#x (pfn %#lx)\n",
388 entry->ref, page_to_pfn(entry->page));
389 put_page(entry->page);
391 pr_info("freeing g.e. %#x\n", entry->ref);
395 if (!--entry->warn_delay)
396 pr_info("g.e. %#x still pending\n", entry->ref);
400 spin_lock_irqsave(&gnttab_list_lock, flags);
402 list_add_tail(&entry->list, &deferred_list);
403 else if (list_empty(&deferred_list))
406 if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
407 deferred_timer.expires = jiffies + HZ;
408 add_timer(&deferred_timer);
410 spin_unlock_irqrestore(&gnttab_list_lock, flags);
413 static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
416 struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
417 const char *what = KERN_WARNING "leaking";
423 entry->ro = readonly;
425 entry->warn_delay = 60;
426 spin_lock_irqsave(&gnttab_list_lock, flags);
427 list_add_tail(&entry->list, &deferred_list);
428 if (!timer_pending(&deferred_timer)) {
429 deferred_timer.expires = jiffies + HZ;
430 add_timer(&deferred_timer);
432 spin_unlock_irqrestore(&gnttab_list_lock, flags);
433 what = KERN_DEBUG "deferring";
435 printk("%s g.e. %#x (pfn %#lx)\n",
436 what, ref, page ? page_to_pfn(page) : -1);
439 void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
442 if (gnttab_end_foreign_access_ref(ref, readonly)) {
445 put_page(virt_to_page(page));
447 gnttab_add_deferred(ref, readonly,
448 page ? virt_to_page(page) : NULL);
450 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
452 int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
456 ref = get_free_entries(1);
457 if (unlikely(ref < 0))
459 gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
463 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
465 void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
468 gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
470 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
472 static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
478 pflags = &gnttab_shared.v1[ref].flags;
481 * If a transfer is not even yet started, try to reclaim the grant
482 * reference and return failure (== 0).
484 while (!((flags = *pflags) & GTF_transfer_committed)) {
485 if (sync_cmpxchg(pflags, flags, 0) == flags)
490 /* If a transfer is in progress then wait until it is completed. */
491 while (!(flags & GTF_transfer_completed)) {
496 rmb(); /* Read the frame number /after/ reading completion status. */
497 frame = gnttab_shared.v1[ref].frame;
503 static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref)
509 pflags = &gnttab_shared.v2[ref].hdr.flags;
512 * If a transfer is not even yet started, try to reclaim the grant
513 * reference and return failure (== 0).
515 while (!((flags = *pflags) & GTF_transfer_committed)) {
516 if (sync_cmpxchg(pflags, flags, 0) == flags)
521 /* If a transfer is in progress then wait until it is completed. */
522 while (!(flags & GTF_transfer_completed)) {
527 rmb(); /* Read the frame number /after/ reading completion status. */
528 frame = gnttab_shared.v2[ref].full_page.frame;
534 unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
536 return gnttab_interface->end_foreign_transfer_ref(ref);
538 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
540 unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
542 unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
546 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
548 void gnttab_free_grant_reference(grant_ref_t ref)
552 EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
554 void gnttab_free_grant_references(grant_ref_t head)
559 if (head == GNTTAB_LIST_END)
561 spin_lock_irqsave(&gnttab_list_lock, flags);
563 while (gnttab_entry(ref) != GNTTAB_LIST_END) {
564 ref = gnttab_entry(ref);
567 gnttab_entry(ref) = gnttab_free_head;
568 gnttab_free_head = head;
569 gnttab_free_count += count;
570 check_free_callbacks();
571 spin_unlock_irqrestore(&gnttab_list_lock, flags);
573 EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
575 int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
577 int h = get_free_entries(count);
586 EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
588 int gnttab_empty_grant_references(const grant_ref_t *private_head)
590 return (*private_head == GNTTAB_LIST_END);
592 EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
594 int gnttab_claim_grant_reference(grant_ref_t *private_head)
596 grant_ref_t g = *private_head;
597 if (unlikely(g == GNTTAB_LIST_END))
599 *private_head = gnttab_entry(g);
602 EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
604 void gnttab_release_grant_reference(grant_ref_t *private_head,
607 gnttab_entry(release) = *private_head;
608 *private_head = release;
610 EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
612 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
613 void (*fn)(void *), void *arg, u16 count)
616 struct gnttab_free_callback *cb;
618 spin_lock_irqsave(&gnttab_list_lock, flags);
620 /* Check if the callback is already on the list */
621 cb = gnttab_free_callback_list;
630 callback->count = count;
631 callback->next = gnttab_free_callback_list;
632 gnttab_free_callback_list = callback;
633 check_free_callbacks();
635 spin_unlock_irqrestore(&gnttab_list_lock, flags);
637 EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
639 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
641 struct gnttab_free_callback **pcb;
644 spin_lock_irqsave(&gnttab_list_lock, flags);
645 for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
646 if (*pcb == callback) {
647 *pcb = callback->next;
651 spin_unlock_irqrestore(&gnttab_list_lock, flags);
653 EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
655 static unsigned int gnttab_frames(unsigned int frames, unsigned int align)
657 return (frames * gnttab_interface->grefs_per_grant_frame + align - 1) /
661 static int grow_gnttab_list(unsigned int more_frames)
663 unsigned int new_nr_grant_frames, extra_entries, i;
664 unsigned int nr_glist_frames, new_nr_glist_frames;
665 unsigned int grefs_per_frame;
667 grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
669 new_nr_grant_frames = nr_grant_frames + more_frames;
670 extra_entries = more_frames * grefs_per_frame;
672 nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
673 new_nr_glist_frames = gnttab_frames(new_nr_grant_frames, RPP);
674 for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
675 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
681 for (i = grefs_per_frame * nr_grant_frames;
682 i < grefs_per_frame * new_nr_grant_frames - 1; i++)
683 gnttab_entry(i) = i + 1;
685 gnttab_entry(i) = gnttab_free_head;
686 gnttab_free_head = grefs_per_frame * nr_grant_frames;
687 gnttab_free_count += extra_entries;
689 nr_grant_frames = new_nr_grant_frames;
691 check_free_callbacks();
696 while (i-- > nr_glist_frames)
697 free_page((unsigned long) gnttab_list[i]);
701 static unsigned int __max_nr_grant_frames(void)
703 struct gnttab_query_size query;
706 query.dom = DOMID_SELF;
708 rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
709 if ((rc < 0) || (query.status != GNTST_okay))
710 return 4; /* Legacy max supported number of frames */
712 return query.max_nr_frames;
715 unsigned int gnttab_max_grant_frames(void)
717 unsigned int xen_max = __max_nr_grant_frames();
718 static unsigned int boot_max_nr_grant_frames;
720 /* First time, initialize it properly. */
721 if (!boot_max_nr_grant_frames)
722 boot_max_nr_grant_frames = __max_nr_grant_frames();
724 if (xen_max > boot_max_nr_grant_frames)
725 return boot_max_nr_grant_frames;
728 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
730 int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
733 unsigned int max_nr_gframes = __max_nr_grant_frames();
737 if (xen_auto_xlat_grant_frames.count)
740 vaddr = xen_remap(addr, XEN_PAGE_SIZE * max_nr_gframes);
742 pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
746 pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
751 for (i = 0; i < max_nr_gframes; i++)
752 pfn[i] = XEN_PFN_DOWN(addr) + i;
754 xen_auto_xlat_grant_frames.vaddr = vaddr;
755 xen_auto_xlat_grant_frames.pfn = pfn;
756 xen_auto_xlat_grant_frames.count = max_nr_gframes;
760 EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
762 void gnttab_free_auto_xlat_frames(void)
764 if (!xen_auto_xlat_grant_frames.count)
766 kfree(xen_auto_xlat_grant_frames.pfn);
767 xen_unmap(xen_auto_xlat_grant_frames.vaddr);
769 xen_auto_xlat_grant_frames.pfn = NULL;
770 xen_auto_xlat_grant_frames.count = 0;
771 xen_auto_xlat_grant_frames.vaddr = NULL;
773 EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
775 int gnttab_pages_set_private(int nr_pages, struct page **pages)
779 for (i = 0; i < nr_pages; i++) {
780 #if BITS_PER_LONG < 64
781 struct xen_page_foreign *foreign;
783 foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
787 set_page_private(pages[i], (unsigned long)foreign);
789 SetPagePrivate(pages[i]);
794 EXPORT_SYMBOL_GPL(gnttab_pages_set_private);
797 * gnttab_alloc_pages - alloc pages suitable for grant mapping into
798 * @nr_pages: number of pages to alloc
799 * @pages: returns the pages
801 int gnttab_alloc_pages(int nr_pages, struct page **pages)
805 ret = alloc_xenballooned_pages(nr_pages, pages);
809 ret = gnttab_pages_set_private(nr_pages, pages);
811 gnttab_free_pages(nr_pages, pages);
815 EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
817 void gnttab_pages_clear_private(int nr_pages, struct page **pages)
821 for (i = 0; i < nr_pages; i++) {
822 if (PagePrivate(pages[i])) {
823 #if BITS_PER_LONG < 64
824 kfree((void *)page_private(pages[i]));
826 ClearPagePrivate(pages[i]);
830 EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);
833 * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
834 * @nr_pages; number of pages to free
837 void gnttab_free_pages(int nr_pages, struct page **pages)
839 gnttab_pages_clear_private(nr_pages, pages);
840 free_xenballooned_pages(nr_pages, pages);
842 EXPORT_SYMBOL_GPL(gnttab_free_pages);
844 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
846 * gnttab_dma_alloc_pages - alloc DMAable pages suitable for grant mapping into
847 * @args: arguments to the function
849 int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args)
851 unsigned long pfn, start_pfn;
855 size = args->nr_pages << PAGE_SHIFT;
857 args->vaddr = dma_alloc_coherent(args->dev, size,
859 GFP_KERNEL | __GFP_NOWARN);
861 args->vaddr = dma_alloc_wc(args->dev, size,
863 GFP_KERNEL | __GFP_NOWARN);
865 pr_debug("Failed to allocate DMA buffer of size %zu\n", size);
869 start_pfn = __phys_to_pfn(args->dev_bus_addr);
870 for (pfn = start_pfn, i = 0; pfn < start_pfn + args->nr_pages;
872 struct page *page = pfn_to_page(pfn);
874 args->pages[i] = page;
875 args->frames[i] = xen_page_to_gfn(page);
876 xenmem_reservation_scrub_page(page);
879 xenmem_reservation_va_mapping_reset(args->nr_pages, args->pages);
881 ret = xenmem_reservation_decrease(args->nr_pages, args->frames);
882 if (ret != args->nr_pages) {
883 pr_debug("Failed to decrease reservation for DMA buffer\n");
888 ret = gnttab_pages_set_private(args->nr_pages, args->pages);
895 gnttab_dma_free_pages(args);
898 EXPORT_SYMBOL_GPL(gnttab_dma_alloc_pages);
901 * gnttab_dma_free_pages - free DMAable pages
902 * @args: arguments to the function
904 int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args)
909 gnttab_pages_clear_private(args->nr_pages, args->pages);
911 for (i = 0; i < args->nr_pages; i++)
912 args->frames[i] = page_to_xen_pfn(args->pages[i]);
914 ret = xenmem_reservation_increase(args->nr_pages, args->frames);
915 if (ret != args->nr_pages) {
916 pr_debug("Failed to increase reservation for DMA buffer\n");
922 xenmem_reservation_va_mapping_update(args->nr_pages, args->pages,
925 size = args->nr_pages << PAGE_SHIFT;
927 dma_free_coherent(args->dev, size,
928 args->vaddr, args->dev_bus_addr);
930 dma_free_wc(args->dev, size,
931 args->vaddr, args->dev_bus_addr);
934 EXPORT_SYMBOL_GPL(gnttab_dma_free_pages);
937 /* Handling of paged out grant targets (GNTST_eagain) */
938 #define MAX_DELAY 256
940 gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
946 BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
947 if (*status == GNTST_eagain)
949 } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
951 if (delay >= MAX_DELAY) {
952 pr_err("%s: %s eagain grant\n", func, current->comm);
953 *status = GNTST_bad_page;
957 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
959 struct gnttab_map_grant_ref *op;
961 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
963 for (op = batch; op < batch + count; op++)
964 if (op->status == GNTST_eagain)
965 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
966 &op->status, __func__);
968 EXPORT_SYMBOL_GPL(gnttab_batch_map);
970 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
972 struct gnttab_copy *op;
974 if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
976 for (op = batch; op < batch + count; op++)
977 if (op->status == GNTST_eagain)
978 gnttab_retry_eagain_gop(GNTTABOP_copy, op,
979 &op->status, __func__);
981 EXPORT_SYMBOL_GPL(gnttab_batch_copy);
983 void gnttab_foreach_grant_in_range(struct page *page,
989 unsigned int goffset;
991 unsigned long xen_pfn;
993 len = min_t(unsigned int, PAGE_SIZE - offset, len);
994 goffset = xen_offset_in_page(offset);
996 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
999 glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
1000 fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
1007 EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
1009 void gnttab_foreach_grant(struct page **pages,
1010 unsigned int nr_grefs,
1014 unsigned int goffset = 0;
1015 unsigned long xen_pfn = 0;
1018 for (i = 0; i < nr_grefs; i++) {
1019 if ((i % XEN_PFN_PER_PAGE) == 0) {
1020 xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
1024 fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
1026 goffset += XEN_PAGE_SIZE;
1031 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
1032 struct gnttab_map_grant_ref *kmap_ops,
1033 struct page **pages, unsigned int count)
1037 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
1041 for (i = 0; i < count; i++) {
1042 switch (map_ops[i].status) {
1045 struct xen_page_foreign *foreign;
1047 SetPageForeign(pages[i]);
1048 foreign = xen_page_foreign(pages[i]);
1049 foreign->domid = map_ops[i].dom;
1050 foreign->gref = map_ops[i].ref;
1054 case GNTST_no_device_space:
1055 pr_warn_ratelimited("maptrack limit reached, can't map all guest pages\n");
1059 /* Retry eagain maps */
1060 gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref,
1062 &map_ops[i].status, __func__);
1063 /* Test status in next loop iteration. */
1072 return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
1074 EXPORT_SYMBOL_GPL(gnttab_map_refs);
1076 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
1077 struct gnttab_unmap_grant_ref *kunmap_ops,
1078 struct page **pages, unsigned int count)
1083 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
1087 for (i = 0; i < count; i++)
1088 ClearPageForeign(pages[i]);
1090 return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
1092 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
1094 #define GNTTAB_UNMAP_REFS_DELAY 5
1096 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
1098 static void gnttab_unmap_work(struct work_struct *work)
1100 struct gntab_unmap_queue_data
1101 *unmap_data = container_of(work,
1102 struct gntab_unmap_queue_data,
1104 if (unmap_data->age != UINT_MAX)
1106 __gnttab_unmap_refs_async(unmap_data);
1109 static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1114 for (pc = 0; pc < item->count; pc++) {
1115 if (page_count(item->pages[pc]) > 1) {
1116 unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
1117 schedule_delayed_work(&item->gnttab_work,
1118 msecs_to_jiffies(delay));
1123 ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
1124 item->pages, item->count);
1125 item->done(ret, item);
1128 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
1130 INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
1133 __gnttab_unmap_refs_async(item);
1135 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
1137 static void unmap_refs_callback(int result,
1138 struct gntab_unmap_queue_data *data)
1140 struct unmap_refs_callback_data *d = data->data;
1143 complete(&d->completion);
1146 int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
1148 struct unmap_refs_callback_data data;
1150 init_completion(&data.completion);
1152 item->done = &unmap_refs_callback;
1153 gnttab_unmap_refs_async(item);
1154 wait_for_completion(&data.completion);
1158 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
1160 static unsigned int nr_status_frames(unsigned int nr_grant_frames)
1162 return gnttab_frames(nr_grant_frames, SPP);
1165 static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
1169 rc = arch_gnttab_map_shared(frames, nr_gframes,
1170 gnttab_max_grant_frames(),
1171 &gnttab_shared.addr);
1177 static void gnttab_unmap_frames_v1(void)
1179 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1182 static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
1185 unsigned int nr_sframes;
1186 struct gnttab_get_status_frames getframes;
1189 nr_sframes = nr_status_frames(nr_gframes);
1191 /* No need for kzalloc as it is initialized in following hypercall
1192 * GNTTABOP_get_status_frames.
1194 sframes = kmalloc_array(nr_sframes, sizeof(uint64_t), GFP_ATOMIC);
1198 getframes.dom = DOMID_SELF;
1199 getframes.nr_frames = nr_sframes;
1200 set_xen_guest_handle(getframes.frame_list, sframes);
1202 rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
1204 if (rc == -ENOSYS) {
1209 BUG_ON(rc || getframes.status);
1211 rc = arch_gnttab_map_status(sframes, nr_sframes,
1212 nr_status_frames(gnttab_max_grant_frames()),
1217 rc = arch_gnttab_map_shared(frames, nr_gframes,
1218 gnttab_max_grant_frames(),
1219 &gnttab_shared.addr);
1225 static void gnttab_unmap_frames_v2(void)
1227 arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
1228 arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
1231 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
1233 struct gnttab_setup_table setup;
1235 unsigned int nr_gframes = end_idx + 1;
1238 if (xen_feature(XENFEAT_auto_translated_physmap)) {
1239 struct xen_add_to_physmap xatp;
1240 unsigned int i = end_idx;
1242 BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
1244 * Loop backwards, so that the first hypercall has the largest
1245 * index, ensuring that the table will grow only once.
1248 xatp.domid = DOMID_SELF;
1250 xatp.space = XENMAPSPACE_grant_table;
1251 xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
1252 rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
1254 pr_warn("grant table add_to_physmap failed, err=%d\n",
1258 } while (i-- > start_idx);
1263 /* No need for kzalloc as it is initialized in following hypercall
1264 * GNTTABOP_setup_table.
1266 frames = kmalloc_array(nr_gframes, sizeof(unsigned long), GFP_ATOMIC);
1270 setup.dom = DOMID_SELF;
1271 setup.nr_frames = nr_gframes;
1272 set_xen_guest_handle(setup.frame_list, frames);
1274 rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
1275 if (rc == -ENOSYS) {
1280 BUG_ON(rc || setup.status);
1282 rc = gnttab_interface->map_frames(frames, nr_gframes);
1289 static const struct gnttab_ops gnttab_v1_ops = {
1291 .grefs_per_grant_frame = XEN_PAGE_SIZE /
1292 sizeof(struct grant_entry_v1),
1293 .map_frames = gnttab_map_frames_v1,
1294 .unmap_frames = gnttab_unmap_frames_v1,
1295 .update_entry = gnttab_update_entry_v1,
1296 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v1,
1297 .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v1,
1298 .query_foreign_access = gnttab_query_foreign_access_v1,
1301 static const struct gnttab_ops gnttab_v2_ops = {
1303 .grefs_per_grant_frame = XEN_PAGE_SIZE /
1304 sizeof(union grant_entry_v2),
1305 .map_frames = gnttab_map_frames_v2,
1306 .unmap_frames = gnttab_unmap_frames_v2,
1307 .update_entry = gnttab_update_entry_v2,
1308 .end_foreign_access_ref = gnttab_end_foreign_access_ref_v2,
1309 .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v2,
1310 .query_foreign_access = gnttab_query_foreign_access_v2,
1313 static bool gnttab_need_v2(void)
1316 uint32_t base, width;
1318 if (xen_pv_domain()) {
1319 base = xen_cpuid_base();
1320 if (cpuid_eax(base) < 5)
1321 return false; /* Information not available, use V1. */
1322 width = cpuid_ebx(base + 5) &
1323 XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
1324 return width > 32 + PAGE_SHIFT;
1327 return !!(max_possible_pfn >> 32);
1330 static void gnttab_request_version(void)
1333 struct gnttab_set_version gsv;
1335 if (gnttab_need_v2())
1340 /* Boot parameter overrides automatic selection. */
1341 if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
1342 gsv.version = xen_gnttab_version;
1344 rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
1345 if (rc == 0 && gsv.version == 2)
1346 gnttab_interface = &gnttab_v2_ops;
1348 gnttab_interface = &gnttab_v1_ops;
1349 pr_info("Grant tables using version %d layout\n",
1350 gnttab_interface->version);
1353 static int gnttab_setup(void)
1355 unsigned int max_nr_gframes;
1357 max_nr_gframes = gnttab_max_grant_frames();
1358 if (max_nr_gframes < nr_grant_frames)
1361 if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
1362 gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
1363 if (gnttab_shared.addr == NULL) {
1364 pr_warn("gnttab share frames is not mapped!\n");
1368 return gnttab_map(0, nr_grant_frames - 1);
1371 int gnttab_resume(void)
1373 gnttab_request_version();
1374 return gnttab_setup();
1377 int gnttab_suspend(void)
1379 if (!xen_feature(XENFEAT_auto_translated_physmap))
1380 gnttab_interface->unmap_frames();
1384 static int gnttab_expand(unsigned int req_entries)
1387 unsigned int cur, extra;
1389 cur = nr_grant_frames;
1390 extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
1391 gnttab_interface->grefs_per_grant_frame);
1392 if (cur + extra > gnttab_max_grant_frames()) {
1393 pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
1394 " cur=%u extra=%u limit=%u"
1395 " gnttab_free_count=%u req_entries=%u\n",
1396 cur, extra, gnttab_max_grant_frames(),
1397 gnttab_free_count, req_entries);
1401 rc = gnttab_map(cur, cur + extra - 1);
1403 rc = grow_gnttab_list(extra);
1408 int gnttab_init(void)
1411 unsigned long max_nr_grant_frames;
1412 unsigned int max_nr_glist_frames, nr_glist_frames;
1413 unsigned int nr_init_grefs;
1416 gnttab_request_version();
1417 max_nr_grant_frames = gnttab_max_grant_frames();
1418 nr_grant_frames = 1;
1420 /* Determine the maximum number of frames required for the
1421 * grant reference free list on the current hypervisor.
1423 max_nr_glist_frames = (max_nr_grant_frames *
1424 gnttab_interface->grefs_per_grant_frame / RPP);
1426 gnttab_list = kmalloc_array(max_nr_glist_frames,
1427 sizeof(grant_ref_t *),
1429 if (gnttab_list == NULL)
1432 nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
1433 for (i = 0; i < nr_glist_frames; i++) {
1434 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
1435 if (gnttab_list[i] == NULL) {
1441 ret = arch_gnttab_init(max_nr_grant_frames,
1442 nr_status_frames(max_nr_grant_frames));
1446 if (gnttab_setup() < 0) {
1451 nr_init_grefs = nr_grant_frames *
1452 gnttab_interface->grefs_per_grant_frame;
1454 for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
1455 gnttab_entry(i) = i + 1;
1457 gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
1458 gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
1459 gnttab_free_head = NR_RESERVED_ENTRIES;
1461 printk("Grant table initialized\n");
1465 for (i--; i >= 0; i--)
1466 free_page((unsigned long)gnttab_list[i]);
1470 EXPORT_SYMBOL_GPL(gnttab_init);
1472 static int __gnttab_init(void)
1477 /* Delay grant-table initialization in the PV on HVM case */
1478 if (xen_hvm_domain() && !xen_pvh_domain())
1481 return gnttab_init();
1483 /* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
1484 * beforehand to initialize xen_auto_xlat_grant_frames. */
1485 core_initcall_sync(__gnttab_init);