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