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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 | /****************************************************************************** * grant_table.h * * Interface for granting foreign access to page frames, and receiving * page-ownership transfers. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to * deal in the Software without restriction, including without limitation the * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or * sell copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. * * Copyright (c) 2004, K A Fraser */ #ifndef __XEN_PUBLIC_GRANT_TABLE_H__ #define __XEN_PUBLIC_GRANT_TABLE_H__ #include <xen/interface/xen.h> /*********************************** * GRANT TABLE REPRESENTATION */ /* Some rough guidelines on accessing and updating grant-table entries * in a concurrency-safe manner. For more information, Linux contains a * reference implementation for guest OSes (arch/xen/kernel/grant_table.c). * * NB. WMB is a no-op on current-generation x86 processors. However, a * compiler barrier will still be required. * * Introducing a valid entry into the grant table: * 1. Write ent->domid. * 2. Write ent->frame: * GTF_permit_access: Frame to which access is permitted. * GTF_accept_transfer: Pseudo-phys frame slot being filled by new * frame, or zero if none. * 3. Write memory barrier (WMB). * 4. Write ent->flags, inc. valid type. * * Invalidating an unused GTF_permit_access entry: * 1. flags = ent->flags. * 2. Observe that !(flags & (GTF_reading|GTF_writing)). * 3. Check result of SMP-safe CMPXCHG(&ent->flags, flags, 0). * NB. No need for WMB as reuse of entry is control-dependent on success of * step 3, and all architectures guarantee ordering of ctrl-dep writes. * * Invalidating an in-use GTF_permit_access entry: * This cannot be done directly. Request assistance from the domain controller * which can set a timeout on the use of a grant entry and take necessary * action. (NB. This is not yet implemented!). * * Invalidating an unused GTF_accept_transfer entry: * 1. flags = ent->flags. * 2. Observe that !(flags & GTF_transfer_committed). [*] * 3. Check result of SMP-safe CMPXCHG(&ent->flags, flags, 0). * NB. No need for WMB as reuse of entry is control-dependent on success of * step 3, and all architectures guarantee ordering of ctrl-dep writes. * [*] If GTF_transfer_committed is set then the grant entry is 'committed'. * The guest must /not/ modify the grant entry until the address of the * transferred frame is written. It is safe for the guest to spin waiting * for this to occur (detect by observing GTF_transfer_completed in * ent->flags). * * Invalidating a committed GTF_accept_transfer entry: * 1. Wait for (ent->flags & GTF_transfer_completed). * * Changing a GTF_permit_access from writable to read-only: * Use SMP-safe CMPXCHG to set GTF_readonly, while checking !GTF_writing. * * Changing a GTF_permit_access from read-only to writable: * Use SMP-safe bit-setting instruction. */ /* * Reference to a grant entry in a specified domain's grant table. */ typedef uint32_t grant_ref_t; /* * A grant table comprises a packed array of grant entries in one or more * page frames shared between Xen and a guest. * [XEN]: This field is written by Xen and read by the sharing guest. * [GST]: This field is written by the guest and read by Xen. */ /* * Version 1 of the grant table entry structure is maintained purely * for backwards compatibility. New guests should use version 2. */ struct grant_entry_v1 { /* GTF_xxx: various type and flag information. [XEN,GST] */ uint16_t flags; /* The domain being granted foreign privileges. [GST] */ domid_t domid; /* * GTF_permit_access: Frame that @domid is allowed to map and access. [GST] * GTF_accept_transfer: Frame whose ownership transferred by @domid. [XEN] */ uint32_t frame; }; /* * Type of grant entry. * GTF_invalid: This grant entry grants no privileges. * GTF_permit_access: Allow @domid to map/access @frame. * GTF_accept_transfer: Allow @domid to transfer ownership of one page frame * to this guest. Xen writes the page number to @frame. * GTF_transitive: Allow @domid to transitively access a subrange of * @trans_grant in @trans_domid. No mappings are allowed. */ #define GTF_invalid (0U<<0) #define GTF_permit_access (1U<<0) #define GTF_accept_transfer (2U<<0) #define GTF_transitive (3U<<0) #define GTF_type_mask (3U<<0) /* * Subflags for GTF_permit_access. * GTF_readonly: Restrict @domid to read-only mappings and accesses. [GST] * GTF_reading: Grant entry is currently mapped for reading by @domid. [XEN] * GTF_writing: Grant entry is currently mapped for writing by @domid. [XEN] * GTF_sub_page: Grant access to only a subrange of the page. @domid * will only be allowed to copy from the grant, and not * map it. [GST] */ #define _GTF_readonly (2) #define GTF_readonly (1U<<_GTF_readonly) #define _GTF_reading (3) #define GTF_reading (1U<<_GTF_reading) #define _GTF_writing (4) #define GTF_writing (1U<<_GTF_writing) #define _GTF_sub_page (8) #define GTF_sub_page (1U<<_GTF_sub_page) /* * Subflags for GTF_accept_transfer: * GTF_transfer_committed: Xen sets this flag to indicate that it is committed * to transferring ownership of a page frame. When a guest sees this flag * it must /not/ modify the grant entry until GTF_transfer_completed is * set by Xen. * GTF_transfer_completed: It is safe for the guest to spin-wait on this flag * after reading GTF_transfer_committed. Xen will always write the frame * address, followed by ORing this flag, in a timely manner. */ #define _GTF_transfer_committed (2) #define GTF_transfer_committed (1U<<_GTF_transfer_committed) #define _GTF_transfer_completed (3) #define GTF_transfer_completed (1U<<_GTF_transfer_completed) /* * Version 2 grant table entries. These fulfil the same role as * version 1 entries, but can represent more complicated operations. * Any given domain will have either a version 1 or a version 2 table, * and every entry in the table will be the same version. * * The interface by which domains use grant references does not depend * on the grant table version in use by the other domain. */ /* * Version 1 and version 2 grant entries share a common prefix. The * fields of the prefix are documented as part of struct * grant_entry_v1. */ struct grant_entry_header { uint16_t flags; domid_t domid; }; /* * Version 2 of the grant entry structure, here is an union because three * different types are suppotted: full_page, sub_page and transitive. */ union grant_entry_v2 { struct grant_entry_header hdr; /* * This member is used for V1-style full page grants, where either: * * -- hdr.type is GTF_accept_transfer, or * -- hdr.type is GTF_permit_access and GTF_sub_page is not set. * * In that case, the frame field has the same semantics as the * field of the same name in the V1 entry structure. */ struct { struct grant_entry_header hdr; uint32_t pad0; uint64_t frame; } full_page; /* * If the grant type is GTF_grant_access and GTF_sub_page is set, * @domid is allowed to access bytes [@page_off,@page_off+@length) * in frame @frame. */ struct { struct grant_entry_header hdr; uint16_t page_off; uint16_t length; uint64_t frame; } sub_page; /* * If the grant is GTF_transitive, @domid is allowed to use the * grant @gref in domain @trans_domid, as if it was the local * domain. Obviously, the transitive access must be compatible * with the original grant. */ struct { struct grant_entry_header hdr; domid_t trans_domid; uint16_t pad0; grant_ref_t gref; } transitive; uint32_t __spacer[4]; /* Pad to a power of two */ }; typedef uint16_t grant_status_t; /*********************************** * GRANT TABLE QUERIES AND USES */ /* * Handle to track a mapping created via a grant reference. */ typedef uint32_t grant_handle_t; /* * GNTTABOP_map_grant_ref: Map the grant entry (<dom>,<ref>) for access * by devices and/or host CPUs. If successful, <handle> is a tracking number * that must be presented later to destroy the mapping(s). On error, <handle> * is a negative status code. * NOTES: * 1. If GNTMAP_device_map is specified then <dev_bus_addr> is the address * via which I/O devices may access the granted frame. * 2. If GNTMAP_host_map is specified then a mapping will be added at * either a host virtual address in the current address space, or at * a PTE at the specified machine address. The type of mapping to * perform is selected through the GNTMAP_contains_pte flag, and the * address is specified in <host_addr>. * 3. Mappings should only be destroyed via GNTTABOP_unmap_grant_ref. If a * host mapping is destroyed by other means then it is *NOT* guaranteed * to be accounted to the correct grant reference! */ #define GNTTABOP_map_grant_ref 0 struct gnttab_map_grant_ref { /* IN parameters. */ uint64_t host_addr; uint32_t flags; /* GNTMAP_* */ grant_ref_t ref; domid_t dom; /* OUT parameters. */ int16_t status; /* GNTST_* */ grant_handle_t handle; uint64_t dev_bus_addr; }; DEFINE_GUEST_HANDLE_STRUCT(gnttab_map_grant_ref); /* * GNTTABOP_unmap_grant_ref: Destroy one or more grant-reference mappings * tracked by <handle>. If <host_addr> or <dev_bus_addr> is zero, that * field is ignored. If non-zero, they must refer to a device/host mapping * that is tracked by <handle> * NOTES: * 1. The call may fail in an undefined manner if either mapping is not * tracked by <handle>. * 3. After executing a batch of unmaps, it is guaranteed that no stale * mappings will remain in the device or host TLBs. */ #define GNTTABOP_unmap_grant_ref 1 struct gnttab_unmap_grant_ref { /* IN parameters. */ uint64_t host_addr; uint64_t dev_bus_addr; grant_handle_t handle; /* OUT parameters. */ int16_t status; /* GNTST_* */ }; DEFINE_GUEST_HANDLE_STRUCT(gnttab_unmap_grant_ref); /* * GNTTABOP_setup_table: Set up a grant table for <dom> comprising at least * <nr_frames> pages. The frame addresses are written to the <frame_list>. * Only <nr_frames> addresses are written, even if the table is larger. * NOTES: * 1. <dom> may be specified as DOMID_SELF. * 2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF. * 3. Xen may not support more than a single grant-table page per domain. */ #define GNTTABOP_setup_table 2 struct gnttab_setup_table { /* IN parameters. */ domid_t dom; uint32_t nr_frames; /* OUT parameters. */ int16_t status; /* GNTST_* */ GUEST_HANDLE(xen_pfn_t) frame_list; }; DEFINE_GUEST_HANDLE_STRUCT(gnttab_setup_table); /* * GNTTABOP_dump_table: Dump the contents of the grant table to the * xen console. Debugging use only. */ #define GNTTABOP_dump_table 3 struct gnttab_dump_table { /* IN parameters. */ domid_t dom; /* OUT parameters. */ int16_t status; /* GNTST_* */ }; DEFINE_GUEST_HANDLE_STRUCT(gnttab_dump_table); /* * GNTTABOP_transfer_grant_ref: Transfer <frame> to a foreign domain. The * foreign domain has previously registered its interest in the transfer via * <domid, ref>. * * Note that, even if the transfer fails, the specified page no longer belongs * to the calling domain *unless* the error is GNTST_bad_page. */ #define GNTTABOP_transfer 4 struct gnttab_transfer { /* IN parameters. */ xen_pfn_t mfn; domid_t domid; grant_ref_t ref; /* OUT parameters. */ int16_t status; }; DEFINE_GUEST_HANDLE_STRUCT(gnttab_transfer); /* * GNTTABOP_copy: Hypervisor based copy * source and destinations can be eithers MFNs or, for foreign domains, * grant references. the foreign domain has to grant read/write access * in its grant table. * * The flags specify what type source and destinations are (either MFN * or grant reference). * * Note that this can also be used to copy data between two domains * via a third party if the source and destination domains had previously * grant appropriate access to their pages to the third party. * * source_offset specifies an offset in the source frame, dest_offset * the offset in the target frame and len specifies the number of * bytes to be copied. */ #define _GNTCOPY_source_gref (0) #define GNTCOPY_source_gref (1<<_GNTCOPY_source_gref) #define _GNTCOPY_dest_gref (1) #define GNTCOPY_dest_gref (1<<_GNTCOPY_dest_gref) #define GNTTABOP_copy 5 struct gnttab_copy { /* IN parameters. */ struct { union { grant_ref_t ref; xen_pfn_t gmfn; } u; domid_t domid; uint16_t offset; } source, dest; uint16_t len; uint16_t flags; /* GNTCOPY_* */ /* OUT parameters. */ int16_t status; }; DEFINE_GUEST_HANDLE_STRUCT(gnttab_copy); /* * GNTTABOP_query_size: Query the current and maximum sizes of the shared * grant table. * NOTES: * 1. <dom> may be specified as DOMID_SELF. * 2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF. */ #define GNTTABOP_query_size 6 struct gnttab_query_size { /* IN parameters. */ domid_t dom; /* OUT parameters. */ uint32_t nr_frames; uint32_t max_nr_frames; int16_t status; /* GNTST_* */ }; DEFINE_GUEST_HANDLE_STRUCT(gnttab_query_size); /* * GNTTABOP_unmap_and_replace: Destroy one or more grant-reference mappings * tracked by <handle> but atomically replace the page table entry with one * pointing to the machine address under <new_addr>. <new_addr> will be * redirected to the null entry. * NOTES: * 1. The call may fail in an undefined manner if either mapping is not * tracked by <handle>. * 2. After executing a batch of unmaps, it is guaranteed that no stale * mappings will remain in the device or host TLBs. */ #define GNTTABOP_unmap_and_replace 7 struct gnttab_unmap_and_replace { /* IN parameters. */ uint64_t host_addr; uint64_t new_addr; grant_handle_t handle; /* OUT parameters. */ int16_t status; /* GNTST_* */ }; DEFINE_GUEST_HANDLE_STRUCT(gnttab_unmap_and_replace); /* * GNTTABOP_set_version: Request a particular version of the grant * table shared table structure. This operation can only be performed * once in any given domain. It must be performed before any grants * are activated; otherwise, the domain will be stuck with version 1. * The only defined versions are 1 and 2. */ #define GNTTABOP_set_version 8 struct gnttab_set_version { /* IN parameters */ uint32_t version; }; DEFINE_GUEST_HANDLE_STRUCT(gnttab_set_version); /* * GNTTABOP_get_status_frames: Get the list of frames used to store grant * status for <dom>. In grant format version 2, the status is separated * from the other shared grant fields to allow more efficient synchronization * using barriers instead of atomic cmpexch operations. * <nr_frames> specify the size of vector <frame_list>. * The frame addresses are returned in the <frame_list>. * Only <nr_frames> addresses are returned, even if the table is larger. * NOTES: * 1. <dom> may be specified as DOMID_SELF. * 2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF. */ #define GNTTABOP_get_status_frames 9 struct gnttab_get_status_frames { /* IN parameters. */ uint32_t nr_frames; domid_t dom; /* OUT parameters. */ int16_t status; /* GNTST_* */ GUEST_HANDLE(uint64_t) frame_list; }; DEFINE_GUEST_HANDLE_STRUCT(gnttab_get_status_frames); /* * GNTTABOP_get_version: Get the grant table version which is in * effect for domain <dom>. */ #define GNTTABOP_get_version 10 struct gnttab_get_version { /* IN parameters */ domid_t dom; uint16_t pad; /* OUT parameters */ uint32_t version; }; DEFINE_GUEST_HANDLE_STRUCT(gnttab_get_version); /* * Bitfield values for update_pin_status.flags. */ /* Map the grant entry for access by I/O devices. */ #define _GNTMAP_device_map (0) #define GNTMAP_device_map (1<<_GNTMAP_device_map) /* Map the grant entry for access by host CPUs. */ #define _GNTMAP_host_map (1) #define GNTMAP_host_map (1<<_GNTMAP_host_map) /* Accesses to the granted frame will be restricted to read-only access. */ #define _GNTMAP_readonly (2) #define GNTMAP_readonly (1<<_GNTMAP_readonly) /* * GNTMAP_host_map subflag: * 0 => The host mapping is usable only by the guest OS. * 1 => The host mapping is usable by guest OS + current application. */ #define _GNTMAP_application_map (3) #define GNTMAP_application_map (1<<_GNTMAP_application_map) /* * GNTMAP_contains_pte subflag: * 0 => This map request contains a host virtual address. * 1 => This map request contains the machine addess of the PTE to update. */ #define _GNTMAP_contains_pte (4) #define GNTMAP_contains_pte (1<<_GNTMAP_contains_pte) /* * Values for error status returns. All errors are -ve. */ #define GNTST_okay (0) /* Normal return. */ #define GNTST_general_error (-1) /* General undefined error. */ #define GNTST_bad_domain (-2) /* Unrecognsed domain id. */ #define GNTST_bad_gntref (-3) /* Unrecognised or inappropriate gntref. */ #define GNTST_bad_handle (-4) /* Unrecognised or inappropriate handle. */ #define GNTST_bad_virt_addr (-5) /* Inappropriate virtual address to map. */ #define GNTST_bad_dev_addr (-6) /* Inappropriate device address to unmap.*/ #define GNTST_no_device_space (-7) /* Out of space in I/O MMU. */ #define GNTST_permission_denied (-8) /* Not enough privilege for operation. */ #define GNTST_bad_page (-9) /* Specified page was invalid for op. */ #define GNTST_bad_copy_arg (-10) /* copy arguments cross page boundary. */ #define GNTST_address_too_big (-11) /* transfer page address too large. */ #define GNTST_eagain (-12) /* Operation not done; try again. */ #define GNTTABOP_error_msgs { \ "okay", \ "undefined error", \ "unrecognised domain id", \ "invalid grant reference", \ "invalid mapping handle", \ "invalid virtual address", \ "invalid device address", \ "no spare translation slot in the I/O MMU", \ "permission denied", \ "bad page", \ "copy arguments cross page boundary", \ "page address size too large", \ "operation not done; try again" \ } #endif /* __XEN_PUBLIC_GRANT_TABLE_H__ */ |