include/xen/grant_table.h

0001 /******************************************************************************
0002  * grant_table.h
0003  *
0004  * Two sets of functionality:
0005  * 1. Granting foreign access to our memory reservation.
0006  * 2. Accessing others' memory reservations via grant references.
0007  * (i.e., mechanisms for both sender and recipient of grant references)
0008  *
0009  * Copyright (c) 2004-2005, K A Fraser
0010  * Copyright (c) 2005, Christopher Clark
0011  *
0012  * This program is free software; you can redistribute it and/or
0013  * modify it under the terms of the GNU General Public License version 2
0014  * as published by the Free Software Foundation; or, when distributed
0015  * separately from the Linux kernel or incorporated into other
0016  * software packages, subject to the following license:
0017  *
0018  * Permission is hereby granted, free of charge, to any person obtaining a copy
0019  * of this source file (the "Software"), to deal in the Software without
0020  * restriction, including without limitation the rights to use, copy, modify,
0021  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
0022  * and to permit persons to whom the Software is furnished to do so, subject to
0023  * the following conditions:
0024  *
0025  * The above copyright notice and this permission notice shall be included in
0026  * all copies or substantial portions of the Software.
0027  *
0028  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
0029  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
0030  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
0031  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
0032  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
0033  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
0034  * IN THE SOFTWARE.
0035  */
0036
0037 #ifndef __ASM_GNTTAB_H__
0038 #define __ASM_GNTTAB_H__
0039
0040 #include <asm/page.h>
0041
0042 #include <xen/interface/xen.h>
0043 #include <xen/interface/grant_table.h>
0044
0045 #include <asm/xen/hypervisor.h>
0046
0047 #include <xen/features.h>
0048 #include <xen/page.h>
0049 #include <linux/mm_types.h>
0050 #include <linux/page-flags.h>
0051 #include <linux/kernel.h>
0052
0053 /*
0054  * Technically there's no reliably invalid grant reference or grant handle,
0055  * so pick the value that is the most unlikely one to be observed valid.
0056  */
0057 #define INVALID_GRANT_REF          ((grant_ref_t)-1)
0058 #define INVALID_GRANT_HANDLE       ((grant_handle_t)-1)
0059
0060 /* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */
0061 #define NR_GRANT_FRAMES 4
0062
0063 struct gnttab_free_callback {
0064     struct gnttab_free_callback *next;
0065     void (*fn)(void *);
0066     void *arg;
0067     u16 count;
0068 };
0069
0070 struct gntab_unmap_queue_data;
0071
0072 typedef void (*gnttab_unmap_refs_done)(int result, struct gntab_unmap_queue_data *data);
0073
0074 struct gntab_unmap_queue_data
0075 {
0076     struct delayed_work gnttab_work;
0077     void *data;
0078     gnttab_unmap_refs_done  done;
0079     struct gnttab_unmap_grant_ref *unmap_ops;
0080     struct gnttab_unmap_grant_ref *kunmap_ops;
0081     struct page **pages;
0082     unsigned int count;
0083     unsigned int age;
0084 };
0085
0086 int gnttab_init(void);
0087 int gnttab_suspend(void);
0088 int gnttab_resume(void);
0089
0090 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
0091                 int readonly);
0092
0093 /*
0094  * End access through the given grant reference, iff the grant entry is no
0095  * longer in use.  Return 1 if the grant entry was freed, 0 if it is still in
0096  * use.
0097  */
0098 int gnttab_end_foreign_access_ref(grant_ref_t ref);
0099
0100 /*
0101  * Eventually end access through the given grant reference, and once that
0102  * access has been ended, free the given page too.  Access will be ended
0103  * immediately iff the grant entry is not in use, otherwise it will happen
0104  * some time later.  page may be NULL, in which case no freeing will occur.
0105  * Note that the granted page might still be accessed (read or write) by the
0106  * other side after gnttab_end_foreign_access() returns, so even if page was
0107  * specified as NULL it is not allowed to just reuse the page for other
0108  * purposes immediately. gnttab_end_foreign_access() will take an additional
0109  * reference to the granted page in this case, which is dropped only after
0110  * the grant is no longer in use.
0111  * This requires that multi page allocations for areas subject to
0112  * gnttab_end_foreign_access() are done via alloc_pages_exact() (and freeing
0113  * via free_pages_exact()) in order to avoid high order pages.
0114  */
0115 void gnttab_end_foreign_access(grant_ref_t ref, struct page *page);
0116
0117 /*
0118  * End access through the given grant reference, iff the grant entry is
0119  * no longer in use.  In case of success ending foreign access, the
0120  * grant reference is deallocated.
0121  * Return 1 if the grant entry was freed, 0 if it is still in use.
0122  */
0123 int gnttab_try_end_foreign_access(grant_ref_t ref);
0124
0125 /*
0126  * operations on reserved batches of grant references
0127  */
0128 int gnttab_alloc_grant_references(u16 count, grant_ref_t *pprivate_head);
0129
0130 int gnttab_alloc_grant_reference_seq(unsigned int count, grant_ref_t *first);
0131
0132 void gnttab_free_grant_reference(grant_ref_t ref);
0133
0134 void gnttab_free_grant_references(grant_ref_t head);
0135
0136 void gnttab_free_grant_reference_seq(grant_ref_t head, unsigned int count);
0137
0138 int gnttab_empty_grant_references(const grant_ref_t *pprivate_head);
0139
0140 int gnttab_claim_grant_reference(grant_ref_t *pprivate_head);
0141
0142 void gnttab_release_grant_reference(grant_ref_t *private_head,
0143                     grant_ref_t release);
0144
0145 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
0146                   void (*fn)(void *), void *arg, u16 count);
0147 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback);
0148
0149 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
0150                      unsigned long frame, int readonly);
0151
0152 /* Give access to the first 4K of the page */
0153 static inline void gnttab_page_grant_foreign_access_ref_one(
0154     grant_ref_t ref, domid_t domid,
0155     struct page *page, int readonly)
0156 {
0157     gnttab_grant_foreign_access_ref(ref, domid, xen_page_to_gfn(page),
0158                     readonly);
0159 }
0160
0161 static inline void
0162 gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr,
0163           uint32_t flags, grant_ref_t ref, domid_t domid)
0164 {
0165     if (flags & GNTMAP_contains_pte)
0166         map->host_addr = addr;
0167     else if (xen_feature(XENFEAT_auto_translated_physmap))
0168         map->host_addr = __pa(addr);
0169     else
0170         map->host_addr = addr;
0171
0172     map->flags = flags;
0173     map->ref = ref;
0174     map->dom = domid;
0175     map->status = 1; /* arbitrary positive value */
0176 }
0177
0178 static inline void
0179 gnttab_set_unmap_op(struct gnttab_unmap_grant_ref *unmap, phys_addr_t addr,
0180             uint32_t flags, grant_handle_t handle)
0181 {
0182     if (flags & GNTMAP_contains_pte)
0183         unmap->host_addr = addr;
0184     else if (xen_feature(XENFEAT_auto_translated_physmap))
0185         unmap->host_addr = __pa(addr);
0186     else
0187         unmap->host_addr = addr;
0188
0189     unmap->handle = handle;
0190     unmap->dev_bus_addr = 0;
0191 }
0192
0193 int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status);
0194 int arch_gnttab_map_shared(xen_pfn_t *frames, unsigned long nr_gframes,
0195                unsigned long max_nr_gframes,
0196                void **__shared);
0197 int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
0198                unsigned long max_nr_gframes,
0199                grant_status_t **__shared);
0200 void arch_gnttab_unmap(void *shared, unsigned long nr_gframes);
0201
0202 struct grant_frames {
0203     xen_pfn_t *pfn;
0204     unsigned int count;
0205     void *vaddr;
0206 };
0207 extern struct grant_frames xen_auto_xlat_grant_frames;
0208 unsigned int gnttab_max_grant_frames(void);
0209 int gnttab_setup_auto_xlat_frames(phys_addr_t addr);
0210 void gnttab_free_auto_xlat_frames(void);
0211
0212 #define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
0213
0214 int gnttab_alloc_pages(int nr_pages, struct page **pages);
0215 void gnttab_free_pages(int nr_pages, struct page **pages);
0216
0217 struct gnttab_page_cache {
0218     spinlock_t      lock;
0219 #ifdef CONFIG_XEN_UNPOPULATED_ALLOC
0220     struct page     *pages;
0221 #else
0222     struct list_head    pages;
0223 #endif
0224     unsigned int        num_pages;
0225 };
0226
0227 void gnttab_page_cache_init(struct gnttab_page_cache *cache);
0228 int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page);
0229 void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
0230                unsigned int num);
0231 void gnttab_page_cache_shrink(struct gnttab_page_cache *cache,
0232                   unsigned int num);
0233
0234 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
0235 struct gnttab_dma_alloc_args {
0236     /* Device for which DMA memory will be/was allocated. */
0237     struct device *dev;
0238     /* If set then DMA buffer is coherent and write-combine otherwise. */
0239     bool coherent;
0240
0241     int nr_pages;
0242     struct page **pages;
0243     xen_pfn_t *frames;
0244     void *vaddr;
0245     dma_addr_t dev_bus_addr;
0246 };
0247
0248 int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args);
0249 int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args);
0250 #endif
0251
0252 int gnttab_pages_set_private(int nr_pages, struct page **pages);
0253 void gnttab_pages_clear_private(int nr_pages, struct page **pages);
0254
0255 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
0256             struct gnttab_map_grant_ref *kmap_ops,
0257             struct page **pages, unsigned int count);
0258 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
0259               struct gnttab_unmap_grant_ref *kunmap_ops,
0260               struct page **pages, unsigned int count);
0261 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
0262 int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item);
0263
0264
0265 /* Perform a batch of grant map/copy operations. Retry every batch slot
0266  * for which the hypervisor returns GNTST_eagain. This is typically due
0267  * to paged out target frames.
0268  *
0269  * Will retry for 1, 2, ... 255 ms, i.e. 256 times during 32 seconds.
0270  *
0271  * Return value in each iand every status field of the batch guaranteed
0272  * to not be GNTST_eagain.
0273  */
0274 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count);
0275 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count);
0276
0277
0278 struct xen_page_foreign {
0279     domid_t domid;
0280     grant_ref_t gref;
0281 };
0282
0283 static inline struct xen_page_foreign *xen_page_foreign(struct page *page)
0284 {
0285     if (!PageForeign(page))
0286         return NULL;
0287 #if BITS_PER_LONG < 64
0288     return (struct xen_page_foreign *)page->private;
0289 #else
0290     BUILD_BUG_ON(sizeof(struct xen_page_foreign) > BITS_PER_LONG);
0291     return (struct xen_page_foreign *)&page->private;
0292 #endif
0293 }
0294
0295 /* Split Linux page in chunk of the size of the grant and call fn
0296  *
0297  * Parameters of fn:
0298  *  gfn: guest frame number
0299  *  offset: offset in the grant
0300  *  len: length of the data in the grant.
0301  *  data: internal information
0302  */
0303 typedef void (*xen_grant_fn_t)(unsigned long gfn, unsigned int offset,
0304                    unsigned int len, void *data);
0305
0306 void gnttab_foreach_grant_in_range(struct page *page,
0307                    unsigned int offset,
0308                    unsigned int len,
0309                    xen_grant_fn_t fn,
0310                    void *data);
0311
0312 /* Helper to get to call fn only on the first "grant chunk" */
0313 static inline void gnttab_for_one_grant(struct page *page, unsigned int offset,
0314                     unsigned len, xen_grant_fn_t fn,
0315                     void *data)
0316 {
0317     /* The first request is limited to the size of one grant */
0318     len = min_t(unsigned int, XEN_PAGE_SIZE - (offset & ~XEN_PAGE_MASK),
0319             len);
0320
0321     gnttab_foreach_grant_in_range(page, offset, len, fn, data);
0322 }
0323
0324 /* Get @nr_grefs grants from an array of page and call fn for each grant */
0325 void gnttab_foreach_grant(struct page **pages,
0326               unsigned int nr_grefs,
0327               xen_grant_fn_t fn,
0328               void *data);
0329
0330 /* Get the number of grant in a specified region
0331  *
0332  * start: Offset from the beginning of the first page
0333  * len: total length of data (can cross multiple page)
0334  */
0335 static inline unsigned int gnttab_count_grant(unsigned int start,
0336                           unsigned int len)
0337 {
0338     return XEN_PFN_UP(xen_offset_in_page(start) + len);
0339 }
0340
0341 #endif /* __ASM_GNTTAB_H__ */