include/xen/grant_table.h

   1 /******************************************************************************
   2  * grant_table.h
   3  *
   4  * Two sets of functionality:
   5  * 1. Granting foreign access to our memory reservation.
   6  * 2. Accessing others' memory reservations via grant references.
   7  * (i.e., mechanisms for both sender and recipient of grant references)
   8  *
   9  * Copyright (c) 2004-2005, K A Fraser
  10  * Copyright (c) 2005, Christopher Clark
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License version 2
  14  * as published by the Free Software Foundation; or, when distributed
  15  * separately from the Linux kernel or incorporated into other
  16  * software packages, subject to the following license:
  17  *
  18  * Permission is hereby granted, free of charge, to any person obtaining a copy
  19  * of this source file (the "Software"), to deal in the Software without
  20  * restriction, including without limitation the rights to use, copy, modify,
  21  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  22  * and to permit persons to whom the Software is furnished to do so, subject to
  23  * the following conditions:
  24  *
  25  * The above copyright notice and this permission notice shall be included in
  26  * all copies or substantial portions of the Software.
  27  *
  28  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  29  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  30  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  31  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  32  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  33  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  34  * IN THE SOFTWARE.
  35  */
  36
  37 #ifndef __ASM_GNTTAB_H__
  38 #define __ASM_GNTTAB_H__
  39
  40 #include <asm/page.h>
  41
  42 #include <xen/interface/xen.h>
  43 #include <xen/interface/grant_table.h>
  44
  45 #include <asm/xen/hypervisor.h>
  46
  47 #include <xen/features.h>
  48 #include <xen/page.h>
  49 #include <linux/mm_types.h>
  50 #include <linux/page-flags.h>
  51 #include <linux/kernel.h>
  52
  53 #define GNTTAB_RESERVED_XENSTORE 1
  54
  55 /* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */
  56 #define NR_GRANT_FRAMES 4
  57
  58 struct gnttab_free_callback {
  59         struct gnttab_free_callback *next;
  60         void (*fn)(void *);
  61         void *arg;
  62         u16 count;
  63 };
  64
  65 struct gntab_unmap_queue_data;
  66
  67 typedef void (*gnttab_unmap_refs_done)(int result, struct gntab_unmap_queue_data *data);
  68
  69 struct gntab_unmap_queue_data
  70 {
  71         struct delayed_work     gnttab_work;
  72         void *data;
  73         gnttab_unmap_refs_done  done;
  74         struct gnttab_unmap_grant_ref *unmap_ops;
  75         struct gnttab_unmap_grant_ref *kunmap_ops;
  76         struct page **pages;
  77         unsigned int count;
  78         unsigned int age;
  79 };
  80
  81 int gnttab_init(void);
  82 int gnttab_suspend(void);
  83 int gnttab_resume(void);
  84
  85 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
  86                                 int readonly);
  87
  88 /*
  89  * End access through the given grant reference, iff the grant entry is no
  90  * longer in use.  Return 1 if the grant entry was freed, 0 if it is still in
  91  * use.
  92  */
  93 int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly);
  94
  95 /*
  96  * Eventually end access through the given grant reference, and once that
  97  * access has been ended, free the given page too.  Access will be ended
  98  * immediately iff the grant entry is not in use, otherwise it will happen
  99  * some time later.  page may be 0, in which case no freeing will occur.
 100  */
 101 void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
 102                                unsigned long page);
 103
 104 int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn);
 105
 106 unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref);
 107 unsigned long gnttab_end_foreign_transfer(grant_ref_t ref);
 108
 109 int gnttab_query_foreign_access(grant_ref_t ref);
 110
 111 /*
 112  * operations on reserved batches of grant references
 113  */
 114 int gnttab_alloc_grant_references(u16 count, grant_ref_t *pprivate_head);
 115
 116 void gnttab_free_grant_reference(grant_ref_t ref);
 117
 118 void gnttab_free_grant_references(grant_ref_t head);
 119
 120 int gnttab_empty_grant_references(const grant_ref_t *pprivate_head);
 121
 122 int gnttab_claim_grant_reference(grant_ref_t *pprivate_head);
 123
 124 void gnttab_release_grant_reference(grant_ref_t *private_head,
 125                                     grant_ref_t release);
 126
 127 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
 128                                   void (*fn)(void *), void *arg, u16 count);
 129 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback);
 130
 131 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
 132                                      unsigned long frame, int readonly);
 133
 134 /* Give access to the first 4K of the page */
 135 static inline void gnttab_page_grant_foreign_access_ref_one(
 136         grant_ref_t ref, domid_t domid,
 137         struct page *page, int readonly)
 138 {
 139         gnttab_grant_foreign_access_ref(ref, domid, xen_page_to_gfn(page),
 140                                         readonly);
 141 }
 142
 143 void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
 144                                        unsigned long pfn);
 145
 146 static inline void
 147 gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr,
 148                   uint32_t flags, grant_ref_t ref, domid_t domid)
 149 {
 150         if (flags & GNTMAP_contains_pte)
 151                 map->host_addr = addr;
 152         else if (xen_feature(XENFEAT_auto_translated_physmap))
 153                 map->host_addr = __pa(addr);
 154         else
 155                 map->host_addr = addr;
 156
 157         map->flags = flags;
 158         map->ref = ref;
 159         map->dom = domid;
 160 }
 161
 162 static inline void
 163 gnttab_set_unmap_op(struct gnttab_unmap_grant_ref *unmap, phys_addr_t addr,
 164                     uint32_t flags, grant_handle_t handle)
 165 {
 166         if (flags & GNTMAP_contains_pte)
 167                 unmap->host_addr = addr;
 168         else if (xen_feature(XENFEAT_auto_translated_physmap))
 169                 unmap->host_addr = __pa(addr);
 170         else
 171                 unmap->host_addr = addr;
 172
 173         unmap->handle = handle;
 174         unmap->dev_bus_addr = 0;
 175 }
 176
 177 int arch_gnttab_init(unsigned long nr_shared);
 178 int arch_gnttab_map_shared(xen_pfn_t *frames, unsigned long nr_gframes,
 179                            unsigned long max_nr_gframes,
 180                            void **__shared);
 181 void arch_gnttab_unmap(void *shared, unsigned long nr_gframes);
 182
 183 struct grant_frames {
 184         xen_pfn_t *pfn;
 185         unsigned int count;
 186         void *vaddr;
 187 };
 188 extern struct grant_frames xen_auto_xlat_grant_frames;
 189 unsigned int gnttab_max_grant_frames(void);
 190 int gnttab_setup_auto_xlat_frames(phys_addr_t addr);
 191 void gnttab_free_auto_xlat_frames(void);
 192
 193 #define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
 194
 195 int gnttab_alloc_pages(int nr_pages, struct page **pages);
 196 void gnttab_free_pages(int nr_pages, struct page **pages);
 197
 198 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
 199                     struct gnttab_map_grant_ref *kmap_ops,
 200                     struct page **pages, unsigned int count);
 201 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
 202                       struct gnttab_unmap_grant_ref *kunmap_ops,
 203                       struct page **pages, unsigned int count);
 204 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
 205 int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item);
 206
 207
 208 /* Perform a batch of grant map/copy operations. Retry every batch slot
 209  * for which the hypervisor returns GNTST_eagain. This is typically due
 210  * to paged out target frames.
 211  *
 212  * Will retry for 1, 2, ... 255 ms, i.e. 256 times during 32 seconds.
 213  *
 214  * Return value in each iand every status field of the batch guaranteed
 215  * to not be GNTST_eagain.
 216  */
 217 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count);
 218 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count);
 219
 220
 221 struct xen_page_foreign {
 222         domid_t domid;
 223         grant_ref_t gref;
 224 };
 225
 226 static inline struct xen_page_foreign *xen_page_foreign(struct page *page)
 227 {
 228         if (!PageForeign(page))
 229                 return NULL;
 230 #if BITS_PER_LONG < 64
 231         return (struct xen_page_foreign *)page->private;
 232 #else
 233         BUILD_BUG_ON(sizeof(struct xen_page_foreign) > BITS_PER_LONG);
 234         return (struct xen_page_foreign *)&page->private;
 235 #endif
 236 }
 237
 238 /* Split Linux page in chunk of the size of the grant and call fn
 239  *
 240  * Parameters of fn:
 241  *      gfn: guest frame number
 242  *      offset: offset in the grant
 243  *      len: length of the data in the grant.
 244  *      data: internal information
 245  */
 246 typedef void (*xen_grant_fn_t)(unsigned long gfn, unsigned int offset,
 247                                unsigned int len, void *data);
 248
 249 void gnttab_foreach_grant_in_range(struct page *page,
 250                                    unsigned int offset,
 251                                    unsigned int len,
 252                                    xen_grant_fn_t fn,
 253                                    void *data);
 254
 255 /* Helper to get to call fn only on the first "grant chunk" */
 256 static inline void gnttab_for_one_grant(struct page *page, unsigned int offset,
 257                                         unsigned len, xen_grant_fn_t fn,
 258                                         void *data)
 259 {
 260         /* The first request is limited to the size of one grant */
 261         len = min_t(unsigned int, XEN_PAGE_SIZE - (offset & ~XEN_PAGE_MASK),
 262                     len);
 263
 264         gnttab_foreach_grant_in_range(page, offset, len, fn, data);
 265 }
 266
 267 /* Get @nr_grefs grants from an array of page and call fn for each grant */
 268 void gnttab_foreach_grant(struct page **pages,
 269                           unsigned int nr_grefs,
 270                           xen_grant_fn_t fn,
 271                           void *data);
 272
 273 /* Get the number of grant in a specified region
 274  *
 275  * start: Offset from the beginning of the first page
 276  * len: total length of data (can cross multiple page)
 277  */
 278 static inline unsigned int gnttab_count_grant(unsigned int start,
 279                                               unsigned int len)
 280 {
 281         return XEN_PFN_UP(xen_offset_in_page(start) + len);
 282 }
 283
 284 #endif /* __ASM_GNTTAB_H__ */