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 /* 54 * Technically there's no reliably invalid grant reference or grant handle, 55 * so pick the value that is the most unlikely one to be observed valid. 56 */ 57 #define INVALID_GRANT_REF ((grant_ref_t)-1) 58 #define INVALID_GRANT_HANDLE ((grant_handle_t)-1) 59 60 /* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */ 61 #define NR_GRANT_FRAMES 4 62 63 struct gnttab_free_callback { 64 struct gnttab_free_callback *next; 65 void (*fn)(void *); 66 void *arg; 67 u16 count; 68 }; 69 70 struct gntab_unmap_queue_data; 71 72 typedef void (*gnttab_unmap_refs_done)(int result, struct gntab_unmap_queue_data *data); 73 74 struct gntab_unmap_queue_data 75 { 76 struct delayed_work gnttab_work; 77 void *data; 78 gnttab_unmap_refs_done done; 79 struct gnttab_unmap_grant_ref *unmap_ops; 80 struct gnttab_unmap_grant_ref *kunmap_ops; 81 struct page **pages; 82 unsigned int count; 83 unsigned int age; 84 }; 85 86 int gnttab_init(void); 87 #ifdef CONFIG_HIBERNATE_CALLBACKS 88 int gnttab_suspend(void); 89 int gnttab_resume(void); 90 #else 91 static inline int gnttab_suspend(void) 92 { 93 return 0; 94 } 95 96 static inline int gnttab_resume(void) 97 { 98 return 0; 99 } 100 #endif 101 102 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame, 103 int readonly); 104 105 /* 106 * End access through the given grant reference, iff the grant entry is no 107 * longer in use. Return 1 if the grant entry was freed, 0 if it is still in 108 * use. 109 */ 110 int gnttab_end_foreign_access_ref(grant_ref_t ref); 111 112 /* 113 * Eventually end access through the given grant reference, and once that 114 * access has been ended, free the given page too. Access will be ended 115 * immediately iff the grant entry is not in use, otherwise it will happen 116 * some time later. page may be NULL, in which case no freeing will occur. 117 * Note that the granted page might still be accessed (read or write) by the 118 * other side after gnttab_end_foreign_access() returns, so even if page was 119 * specified as NULL it is not allowed to just reuse the page for other 120 * purposes immediately. gnttab_end_foreign_access() will take an additional 121 * reference to the granted page in this case, which is dropped only after 122 * the grant is no longer in use. 123 * This requires that multi page allocations for areas subject to 124 * gnttab_end_foreign_access() are done via alloc_pages_exact() (and freeing 125 * via free_pages_exact()) in order to avoid high order pages. 126 */ 127 void gnttab_end_foreign_access(grant_ref_t ref, struct page *page); 128 129 /* 130 * End access through the given grant reference, iff the grant entry is 131 * no longer in use. In case of success ending foreign access, the 132 * grant reference is deallocated. 133 * Return 1 if the grant entry was freed, 0 if it is still in use. 134 */ 135 int gnttab_try_end_foreign_access(grant_ref_t ref); 136 137 /* 138 * operations on reserved batches of grant references 139 */ 140 int gnttab_alloc_grant_references(u16 count, grant_ref_t *pprivate_head); 141 142 int gnttab_alloc_grant_reference_seq(unsigned int count, grant_ref_t *first); 143 144 void gnttab_free_grant_reference(grant_ref_t ref); 145 146 void gnttab_free_grant_references(grant_ref_t head); 147 148 void gnttab_free_grant_reference_seq(grant_ref_t head, unsigned int count); 149 150 int gnttab_empty_grant_references(const grant_ref_t *pprivate_head); 151 152 int gnttab_claim_grant_reference(grant_ref_t *pprivate_head); 153 154 void gnttab_release_grant_reference(grant_ref_t *private_head, 155 grant_ref_t release); 156 157 void gnttab_request_free_callback(struct gnttab_free_callback *callback, 158 void (*fn)(void *), void *arg, u16 count); 159 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback); 160 161 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid, 162 unsigned long frame, int readonly); 163 164 /* Give access to the first 4K of the page */ 165 static inline void gnttab_page_grant_foreign_access_ref_one( 166 grant_ref_t ref, domid_t domid, 167 struct page *page, int readonly) 168 { 169 gnttab_grant_foreign_access_ref(ref, domid, xen_page_to_gfn(page), 170 readonly); 171 } 172 173 static inline void 174 gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr, 175 uint32_t flags, grant_ref_t ref, domid_t domid) 176 { 177 if (flags & GNTMAP_contains_pte) 178 map->host_addr = addr; 179 else if (!xen_pv_domain()) 180 map->host_addr = __pa(addr); 181 else 182 map->host_addr = addr; 183 184 map->flags = flags; 185 map->ref = ref; 186 map->dom = domid; 187 map->status = 1; /* arbitrary positive value */ 188 } 189 190 static inline void 191 gnttab_set_unmap_op(struct gnttab_unmap_grant_ref *unmap, phys_addr_t addr, 192 uint32_t flags, grant_handle_t handle) 193 { 194 if (flags & GNTMAP_contains_pte) 195 unmap->host_addr = addr; 196 else if (!xen_pv_domain()) 197 unmap->host_addr = __pa(addr); 198 else 199 unmap->host_addr = addr; 200 201 unmap->handle = handle; 202 unmap->dev_bus_addr = 0; 203 } 204 205 int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status); 206 int arch_gnttab_map_shared(xen_pfn_t *frames, unsigned long nr_gframes, 207 unsigned long max_nr_gframes, 208 void **__shared); 209 int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes, 210 unsigned long max_nr_gframes, 211 grant_status_t **__shared); 212 void arch_gnttab_unmap(void *shared, unsigned long nr_gframes); 213 214 struct grant_frames { 215 xen_pfn_t *pfn; 216 unsigned int count; 217 void *vaddr; 218 }; 219 extern struct grant_frames xen_auto_xlat_grant_frames; 220 unsigned int gnttab_max_grant_frames(void); 221 int gnttab_setup_auto_xlat_frames(phys_addr_t addr); 222 void gnttab_free_auto_xlat_frames(void); 223 224 #define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr)) 225 226 int gnttab_alloc_pages(int nr_pages, struct page **pages); 227 void gnttab_free_pages(int nr_pages, struct page **pages); 228 229 struct gnttab_page_cache { 230 spinlock_t lock; 231 #ifdef CONFIG_XEN_UNPOPULATED_ALLOC 232 struct page *pages; 233 #else 234 struct list_head pages; 235 #endif 236 unsigned int num_pages; 237 }; 238 239 void gnttab_page_cache_init(struct gnttab_page_cache *cache); 240 int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page); 241 void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page, 242 unsigned int num); 243 void gnttab_page_cache_shrink(struct gnttab_page_cache *cache, 244 unsigned int num); 245 246 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC 247 struct gnttab_dma_alloc_args { 248 /* Device for which DMA memory will be/was allocated. */ 249 struct device *dev; 250 /* If set then DMA buffer is coherent and write-combine otherwise. */ 251 bool coherent; 252 253 int nr_pages; 254 struct page **pages; 255 xen_pfn_t *frames; 256 void *vaddr; 257 dma_addr_t dev_bus_addr; 258 }; 259 260 int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args); 261 int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args); 262 #endif 263 264 int gnttab_pages_set_private(int nr_pages, struct page **pages); 265 void gnttab_pages_clear_private(int nr_pages, struct page **pages); 266 267 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, 268 struct gnttab_map_grant_ref *kmap_ops, 269 struct page **pages, unsigned int count); 270 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, 271 struct gnttab_unmap_grant_ref *kunmap_ops, 272 struct page **pages, unsigned int count); 273 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item); 274 int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item); 275 276 277 /* Perform a batch of grant map/copy operations. Retry every batch slot 278 * for which the hypervisor returns GNTST_eagain. This is typically due 279 * to paged out target frames. 280 * 281 * Will retry for 1, 2, ... 255 ms, i.e. 256 times during 32 seconds. 282 * 283 * Return value in each iand every status field of the batch guaranteed 284 * to not be GNTST_eagain. 285 */ 286 void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count); 287 void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count); 288 289 290 struct xen_page_foreign { 291 domid_t domid; 292 grant_ref_t gref; 293 }; 294 295 static inline struct xen_page_foreign *xen_page_foreign(struct page *page) 296 { 297 if (!PageForeign(page)) 298 return NULL; 299 #if BITS_PER_LONG < 64 300 return (struct xen_page_foreign *)page->private; 301 #else 302 BUILD_BUG_ON(sizeof(struct xen_page_foreign) > BITS_PER_LONG); 303 return (struct xen_page_foreign *)&page->private; 304 #endif 305 } 306 307 /* Split Linux page in chunk of the size of the grant and call fn 308 * 309 * Parameters of fn: 310 * gfn: guest frame number 311 * offset: offset in the grant 312 * len: length of the data in the grant. 313 * data: internal information 314 */ 315 typedef void (*xen_grant_fn_t)(unsigned long gfn, unsigned int offset, 316 unsigned int len, void *data); 317 318 void gnttab_foreach_grant_in_range(struct page *page, 319 unsigned int offset, 320 unsigned int len, 321 xen_grant_fn_t fn, 322 void *data); 323 324 /* Helper to get to call fn only on the first "grant chunk" */ 325 static inline void gnttab_for_one_grant(struct page *page, unsigned int offset, 326 unsigned len, xen_grant_fn_t fn, 327 void *data) 328 { 329 /* The first request is limited to the size of one grant */ 330 len = min_t(unsigned int, XEN_PAGE_SIZE - (offset & ~XEN_PAGE_MASK), 331 len); 332 333 gnttab_foreach_grant_in_range(page, offset, len, fn, data); 334 } 335 336 /* Get @nr_grefs grants from an array of page and call fn for each grant */ 337 void gnttab_foreach_grant(struct page **pages, 338 unsigned int nr_grefs, 339 xen_grant_fn_t fn, 340 void *data); 341 342 /* Get the number of grant in a specified region 343 * 344 * start: Offset from the beginning of the first page 345 * len: total length of data (can cross multiple page) 346 */ 347 static inline unsigned int gnttab_count_grant(unsigned int start, 348 unsigned int len) 349 { 350 return XEN_PFN_UP(xen_offset_in_page(start) + len); 351 } 352 353 #endif /* __ASM_GNTTAB_H__ */ 354