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