| 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__ */ |