1 /******************************************************************************
2  * grant_table.h
3  *
4  * Interface for granting foreign access to page frames, and receiving
5  * page-ownership transfers.
6  *
7  * Permission is hereby granted, free of charge, to any person obtaining a copy
8  * of this software and associated documentation files (the "Software"), to
9  * deal in the Software without restriction, including without limitation the
10  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
11  * sell copies of the Software, and to permit persons to whom the Software is
12  * furnished to do so, subject to the following conditions:
13  *
14  * The above copyright notice and this permission notice shall be included in
15  * all copies or substantial portions of the Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
22  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
23  * DEALINGS IN THE SOFTWARE.
24  *
25  * Copyright (c) 2004, K A Fraser
26  */
27 
28 #ifndef __XEN_PUBLIC_GRANT_TABLE_H__
29 #define __XEN_PUBLIC_GRANT_TABLE_H__
30 
31 #include "xen.h"
32 
33 /*
34  * `incontents 150 gnttab Grant Tables
35  *
36  * Xen's grant tables provide a generic mechanism to memory sharing
37  * between domains. This shared memory interface underpins the split
38  * device drivers for block and network IO.
39  *
40  * Each domain has its own grant table. This is a data structure that
41  * is shared with Xen; it allows the domain to tell Xen what kind of
42  * permissions other domains have on its pages. Entries in the grant
43  * table are identified by grant references. A grant reference is an
44  * integer, which indexes into the grant table. It acts as a
45  * capability which the grantee can use to perform operations on the
46  * granter's memory.
47  *
48  * This capability-based system allows shared-memory communications
49  * between unprivileged domains. A grant reference also encapsulates
50  * the details of a shared page, removing the need for a domain to
51  * know the real machine address of a page it is sharing. This makes
52  * it possible to share memory correctly with domains running in
53  * fully virtualised memory.
54  */
55 
56 /***********************************
57  * GRANT TABLE REPRESENTATION
58  */
59 
60 /* Some rough guidelines on accessing and updating grant-table entries
61  * in a concurrency-safe manner. For more information, Linux contains a
62  * reference implementation for guest OSes (drivers/xen/grant_table.c, see
63  * http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=drivers/xen/grant-table.c;hb=HEAD
64  *
65  * NB. WMB is a no-op on current-generation x86 processors. However, a
66  *     compiler barrier will still be required.
67  *
68  * Introducing a valid entry into the grant table:
69  *  1. Write ent->domid.
70  *  2. Write ent->frame:
71  *      GTF_permit_access:   Frame to which access is permitted.
72  *      GTF_accept_transfer: Pseudo-phys frame slot being filled by new
73  *                           frame, or zero if none.
74  *  3. Write memory barrier (WMB).
75  *  4. Write ent->flags, inc. valid type.
76  *
77  * Invalidating an unused GTF_permit_access entry:
78  *  1. flags = ent->flags.
79  *  2. Observe that !(flags & (GTF_reading|GTF_writing)).
80  *  3. Check result of SMP-safe CMPXCHG(&ent->flags, flags, 0).
81  *  NB. No need for WMB as reuse of entry is control-dependent on success of
82  *      step 3, and all architectures guarantee ordering of ctrl-dep writes.
83  *
84  * Invalidating an in-use GTF_permit_access entry:
85  *  This cannot be done directly. Request assistance from the domain controller
86  *  which can set a timeout on the use of a grant entry and take necessary
87  *  action. (NB. This is not yet implemented!).
88  *
89  * Invalidating an unused GTF_accept_transfer entry:
90  *  1. flags = ent->flags.
91  *  2. Observe that !(flags & GTF_transfer_committed). [*]
92  *  3. Check result of SMP-safe CMPXCHG(&ent->flags, flags, 0).
93  *  NB. No need for WMB as reuse of entry is control-dependent on success of
94  *      step 3, and all architectures guarantee ordering of ctrl-dep writes.
95  *  [*] If GTF_transfer_committed is set then the grant entry is 'committed'.
96  *      The guest must /not/ modify the grant entry until the address of the
97  *      transferred frame is written. It is safe for the guest to spin waiting
98  *      for this to occur (detect by observing GTF_transfer_completed in
99  *      ent->flags).
100  *
101  * Invalidating a committed GTF_accept_transfer entry:
102  *  1. Wait for (ent->flags & GTF_transfer_completed).
103  *
104  * Changing a GTF_permit_access from writable to read-only:
105  *  Use SMP-safe CMPXCHG to set GTF_readonly, while checking !GTF_writing.
106  *
107  * Changing a GTF_permit_access from read-only to writable:
108  *  Use SMP-safe bit-setting instruction.
109  */
110 
111 /*
112  * Reference to a grant entry in a specified domain's grant table.
113  */
114 typedef uint32_t grant_ref_t;
115 
116 /*
117  * A grant table comprises a packed array of grant entries in one or more
118  * page frames shared between Xen and a guest.
119  * [XEN]: This field is written by Xen and read by the sharing guest.
120  * [GST]: This field is written by the guest and read by Xen.
121  */
122 
123 /*
124  * Version 1 of the grant table entry structure is maintained purely
125  * for backwards compatibility.  New guests should use version 2.
126  */
127 #if __XEN_INTERFACE_VERSION__ < 0x0003020a
128 #define grant_entry_v1 grant_entry
129 #define grant_entry_v1_t grant_entry_t
130 #endif
131 struct grant_entry_v1 {
132     /* GTF_xxx: various type and flag information.  [XEN,GST] */
133     uint16_t flags;
134     /* The domain being granted foreign privileges. [GST] */
135     domid_t  domid;
136     /*
137      * GTF_permit_access: GFN that @domid is allowed to map and access. [GST]
138      * GTF_accept_transfer: GFN that @domid is allowed to transfer into. [GST]
139      * GTF_transfer_completed: MFN whose ownership transferred by @domid
140      *                         (non-translated guests only). [XEN]
141      */
142     uint32_t frame;
143 };
144 typedef struct grant_entry_v1 grant_entry_v1_t;
145 
146 /* The first few grant table entries will be preserved across grant table
147  * version changes and may be pre-populated at domain creation by tools.
148  */
149 #define GNTTAB_NR_RESERVED_ENTRIES     8
150 #define GNTTAB_RESERVED_CONSOLE        0
151 #define GNTTAB_RESERVED_XENSTORE       1
152 
153 /*
154  * Type of grant entry.
155  *  GTF_invalid: This grant entry grants no privileges.
156  *  GTF_permit_access: Allow @domid to map/access @frame.
157  *  GTF_accept_transfer: Allow @domid to transfer ownership of one page frame
158  *                       to this guest. Xen writes the page number to @frame.
159  *  GTF_transitive: Allow @domid to transitively access a subrange of
160  *                  @trans_grant in @trans_domid.  No mappings are allowed.
161  */
162 #define GTF_invalid         (0U<<0)
163 #define GTF_permit_access   (1U<<0)
164 #define GTF_accept_transfer (2U<<0)
165 #define GTF_transitive      (3U<<0)
166 #define GTF_type_mask       (3U<<0)
167 
168 /*
169  * Subflags for GTF_permit_access.
170  *  GTF_readonly: Restrict @domid to read-only mappings and accesses. [GST]
171  *  GTF_reading: Grant entry is currently mapped for reading by @domid. [XEN]
172  *  GTF_writing: Grant entry is currently mapped for writing by @domid. [XEN]
173  *  GTF_PAT, GTF_PWT, GTF_PCD: (x86) cache attribute flags for the grant [GST]
174  *  GTF_sub_page: Grant access to only a subrange of the page.  @domid
175  *                will only be allowed to copy from the grant, and not
176  *                map it. [GST]
177  */
178 #define _GTF_readonly       (2)
179 #define GTF_readonly        (1U<<_GTF_readonly)
180 #define _GTF_reading        (3)
181 #define GTF_reading         (1U<<_GTF_reading)
182 #define _GTF_writing        (4)
183 #define GTF_writing         (1U<<_GTF_writing)
184 #define _GTF_PWT            (5)
185 #define GTF_PWT             (1U<<_GTF_PWT)
186 #define _GTF_PCD            (6)
187 #define GTF_PCD             (1U<<_GTF_PCD)
188 #define _GTF_PAT            (7)
189 #define GTF_PAT             (1U<<_GTF_PAT)
190 #define _GTF_sub_page       (8)
191 #define GTF_sub_page        (1U<<_GTF_sub_page)
192 
193 /*
194  * Subflags for GTF_accept_transfer:
195  *  GTF_transfer_committed: Xen sets this flag to indicate that it is committed
196  *      to transferring ownership of a page frame. When a guest sees this flag
197  *      it must /not/ modify the grant entry until GTF_transfer_completed is
198  *      set by Xen.
199  *  GTF_transfer_completed: It is safe for the guest to spin-wait on this flag
200  *      after reading GTF_transfer_committed. Xen will always write the frame
201  *      address, followed by ORing this flag, in a timely manner.
202  */
203 #define _GTF_transfer_committed (2)
204 #define GTF_transfer_committed  (1U<<_GTF_transfer_committed)
205 #define _GTF_transfer_completed (3)
206 #define GTF_transfer_completed  (1U<<_GTF_transfer_completed)
207 
208 /*
209  * Version 2 grant table entries.  These fulfil the same role as
210  * version 1 entries, but can represent more complicated operations.
211  * Any given domain will have either a version 1 or a version 2 table,
212  * and every entry in the table will be the same version.
213  *
214  * The interface by which domains use grant references does not depend
215  * on the grant table version in use by the other domain.
216  */
217 #if __XEN_INTERFACE_VERSION__ >= 0x0003020a
218 /*
219  * Version 1 and version 2 grant entries share a common prefix.  The
220  * fields of the prefix are documented as part of struct
221  * grant_entry_v1.
222  */
223 struct grant_entry_header {
224     uint16_t flags;
225     domid_t  domid;
226 };
227 typedef struct grant_entry_header grant_entry_header_t;
228 
229 /*
230  * Version 2 of the grant entry structure.
231  */
232 union grant_entry_v2 {
233     grant_entry_header_t hdr;
234 
235     /*
236      * This member is used for V1-style full page grants, where either:
237      *
238      * -- hdr.type is GTF_accept_transfer, or
239      * -- hdr.type is GTF_permit_access and GTF_sub_page is not set.
240      *
241      * In that case, the frame field has the same semantics as the
242      * field of the same name in the V1 entry structure.
243      */
244     struct {
245         grant_entry_header_t hdr;
246         uint32_t pad0;
247         uint64_t frame;
248     } full_page;
249 
250     /*
251      * If the grant type is GTF_grant_access and GTF_sub_page is set,
252      * @domid is allowed to access bytes [@page_off,@page_off+@length)
253      * in frame @frame.
254      */
255     struct {
256         grant_entry_header_t hdr;
257         uint16_t page_off;
258         uint16_t length;
259         uint64_t frame;
260     } sub_page;
261 
262     /*
263      * If the grant is GTF_transitive, @domid is allowed to use the
264      * grant @gref in domain @trans_domid, as if it was the local
265      * domain.  Obviously, the transitive access must be compatible
266      * with the original grant.
267      *
268      * The current version of Xen does not allow transitive grants
269      * to be mapped.
270      */
271     struct {
272         grant_entry_header_t hdr;
273         domid_t trans_domid;
274         uint16_t pad0;
275         grant_ref_t gref;
276     } transitive;
277 
278     uint32_t __spacer[4]; /* Pad to a power of two */
279 };
280 typedef union grant_entry_v2 grant_entry_v2_t;
281 
282 typedef uint16_t grant_status_t;
283 
284 #endif /* __XEN_INTERFACE_VERSION__ */
285 
286 /***********************************
287  * GRANT TABLE QUERIES AND USES
288  */
289 
290 /* ` enum neg_errnoval
291  * ` HYPERVISOR_grant_table_op(enum grant_table_op cmd,
292  * `                           void *args,
293  * `                           unsigned int count)
294  * `
295  *
296  * @args points to an array of a per-command data structure. The array
297  * has @count members
298  */
299 
300 /* ` enum grant_table_op { // GNTTABOP_* => struct gnttab_* */
301 #define GNTTABOP_map_grant_ref        0
302 #define GNTTABOP_unmap_grant_ref      1
303 #define GNTTABOP_setup_table          2
304 #define GNTTABOP_dump_table           3
305 #define GNTTABOP_transfer             4
306 #define GNTTABOP_copy                 5
307 #define GNTTABOP_query_size           6
308 #define GNTTABOP_unmap_and_replace    7
309 #if __XEN_INTERFACE_VERSION__ >= 0x0003020a
310 #define GNTTABOP_set_version          8
311 #define GNTTABOP_get_status_frames    9
312 #define GNTTABOP_get_version          10
313 #define GNTTABOP_swap_grant_ref	      11
314 #define GNTTABOP_cache_flush	      12
315 #endif /* __XEN_INTERFACE_VERSION__ */
316 /* ` } */
317 
318 /*
319  * Handle to track a mapping created via a grant reference.
320  */
321 typedef uint32_t grant_handle_t;
322 
323 /*
324  * GNTTABOP_map_grant_ref: Map the grant entry (<dom>,<ref>) for access
325  * by devices and/or host CPUs. If successful, <handle> is a tracking number
326  * that must be presented later to destroy the mapping(s). On error, <status>
327  * is a negative status code.
328  * NOTES:
329  *  1. If GNTMAP_device_map is specified then <dev_bus_addr> is the address
330  *     via which I/O devices may access the granted frame.
331  *  2. If GNTMAP_host_map is specified then a mapping will be added at
332  *     either a host virtual address in the current address space, or at
333  *     a PTE at the specified machine address.  The type of mapping to
334  *     perform is selected through the GNTMAP_contains_pte flag, and the
335  *     address is specified in <host_addr>.
336  *  3. Mappings should only be destroyed via GNTTABOP_unmap_grant_ref. If a
337  *     host mapping is destroyed by other means then it is *NOT* guaranteed
338  *     to be accounted to the correct grant reference!
339  */
340 struct gnttab_map_grant_ref {
341     /* IN parameters. */
342     uint64_t host_addr;
343     uint32_t flags;               /* GNTMAP_* */
344     grant_ref_t ref;
345     domid_t  dom;
346     /* OUT parameters. */
347     int16_t  status;              /* => enum grant_status */
348     grant_handle_t handle;
349     uint64_t dev_bus_addr;
350 };
351 typedef struct gnttab_map_grant_ref gnttab_map_grant_ref_t;
352 DEFINE_XEN_GUEST_HANDLE(gnttab_map_grant_ref_t);
353 
354 /*
355  * GNTTABOP_unmap_grant_ref: Destroy one or more grant-reference mappings
356  * tracked by <handle>. If <host_addr> or <dev_bus_addr> is zero, that
357  * field is ignored. If non-zero, they must refer to a device/host mapping
358  * that is tracked by <handle>
359  * NOTES:
360  *  1. The call may fail in an undefined manner if either mapping is not
361  *     tracked by <handle>.
362  *  3. After executing a batch of unmaps, it is guaranteed that no stale
363  *     mappings will remain in the device or host TLBs.
364  */
365 struct gnttab_unmap_grant_ref {
366     /* IN parameters. */
367     uint64_t host_addr;
368     uint64_t dev_bus_addr;
369     grant_handle_t handle;
370     /* OUT parameters. */
371     int16_t  status;              /* => enum grant_status */
372 };
373 typedef struct gnttab_unmap_grant_ref gnttab_unmap_grant_ref_t;
374 DEFINE_XEN_GUEST_HANDLE(gnttab_unmap_grant_ref_t);
375 
376 /*
377  * GNTTABOP_setup_table: Set up a grant table for <dom> comprising at least
378  * <nr_frames> pages. The frame addresses are written to the <frame_list>.
379  * Only <nr_frames> addresses are written, even if the table is larger.
380  * NOTES:
381  *  1. <dom> may be specified as DOMID_SELF.
382  *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
383  *  3. Xen may not support more than a single grant-table page per domain.
384  */
385 struct gnttab_setup_table {
386     /* IN parameters. */
387     domid_t  dom;
388     uint32_t nr_frames;
389     /* OUT parameters. */
390     int16_t  status;              /* => enum grant_status */
391 #if __XEN_INTERFACE_VERSION__ < 0x00040300
392     XEN_GUEST_HANDLE(ulong) frame_list;
393 #else
394     XEN_GUEST_HANDLE(xen_pfn_t) frame_list;
395 #endif
396 };
397 typedef struct gnttab_setup_table gnttab_setup_table_t;
398 DEFINE_XEN_GUEST_HANDLE(gnttab_setup_table_t);
399 
400 /*
401  * GNTTABOP_dump_table: Dump the contents of the grant table to the
402  * xen console. Debugging use only.
403  */
404 struct gnttab_dump_table {
405     /* IN parameters. */
406     domid_t dom;
407     /* OUT parameters. */
408     int16_t status;               /* => enum grant_status */
409 };
410 typedef struct gnttab_dump_table gnttab_dump_table_t;
411 DEFINE_XEN_GUEST_HANDLE(gnttab_dump_table_t);
412 
413 /*
414  * GNTTABOP_transfer: Transfer <frame> to a foreign domain. The foreign domain
415  * has previously registered its interest in the transfer via <domid, ref>.
416  *
417  * Note that, even if the transfer fails, the specified page no longer belongs
418  * to the calling domain *unless* the error is GNTST_bad_page.
419  *
420  * Note further that only PV guests can use this operation.
421  */
422 struct gnttab_transfer {
423     /* IN parameters. */
424     xen_pfn_t     mfn;
425     domid_t       domid;
426     grant_ref_t   ref;
427     /* OUT parameters. */
428     int16_t       status;
429 };
430 typedef struct gnttab_transfer gnttab_transfer_t;
431 DEFINE_XEN_GUEST_HANDLE(gnttab_transfer_t);
432 
433 
434 /*
435  * GNTTABOP_copy: Hypervisor based copy
436  * source and destinations can be eithers MFNs or, for foreign domains,
437  * grant references. the foreign domain has to grant read/write access
438  * in its grant table.
439  *
440  * The flags specify what type source and destinations are (either MFN
441  * or grant reference).
442  *
443  * Note that this can also be used to copy data between two domains
444  * via a third party if the source and destination domains had previously
445  * grant appropriate access to their pages to the third party.
446  *
447  * source_offset specifies an offset in the source frame, dest_offset
448  * the offset in the target frame and  len specifies the number of
449  * bytes to be copied.
450  */
451 
452 #define _GNTCOPY_source_gref      (0)
453 #define GNTCOPY_source_gref       (1<<_GNTCOPY_source_gref)
454 #define _GNTCOPY_dest_gref        (1)
455 #define GNTCOPY_dest_gref         (1<<_GNTCOPY_dest_gref)
456 
457 struct gnttab_copy {
458     /* IN parameters. */
459     struct gnttab_copy_ptr {
460         union {
461             grant_ref_t ref;
462             xen_pfn_t   gmfn;
463         } u;
464         domid_t  domid;
465         uint16_t offset;
466     } source, dest;
467     uint16_t      len;
468     uint16_t      flags;          /* GNTCOPY_* */
469     /* OUT parameters. */
470     int16_t       status;
471 };
472 typedef struct gnttab_copy  gnttab_copy_t;
473 DEFINE_XEN_GUEST_HANDLE(gnttab_copy_t);
474 
475 /*
476  * GNTTABOP_query_size: Query the current and maximum sizes of the shared
477  * grant table.
478  * NOTES:
479  *  1. <dom> may be specified as DOMID_SELF.
480  *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
481  */
482 struct gnttab_query_size {
483     /* IN parameters. */
484     domid_t  dom;
485     /* OUT parameters. */
486     uint32_t nr_frames;
487     uint32_t max_nr_frames;
488     int16_t  status;              /* => enum grant_status */
489 };
490 typedef struct gnttab_query_size gnttab_query_size_t;
491 DEFINE_XEN_GUEST_HANDLE(gnttab_query_size_t);
492 
493 /*
494  * GNTTABOP_unmap_and_replace: Destroy one or more grant-reference mappings
495  * tracked by <handle> but atomically replace the page table entry with one
496  * pointing to the machine address under <new_addr>.  <new_addr> will be
497  * redirected to the null entry.
498  * NOTES:
499  *  1. The call may fail in an undefined manner if either mapping is not
500  *     tracked by <handle>.
501  *  2. After executing a batch of unmaps, it is guaranteed that no stale
502  *     mappings will remain in the device or host TLBs.
503  */
504 struct gnttab_unmap_and_replace {
505     /* IN parameters. */
506     uint64_t host_addr;
507     uint64_t new_addr;
508     grant_handle_t handle;
509     /* OUT parameters. */
510     int16_t  status;              /* => enum grant_status */
511 };
512 typedef struct gnttab_unmap_and_replace gnttab_unmap_and_replace_t;
513 DEFINE_XEN_GUEST_HANDLE(gnttab_unmap_and_replace_t);
514 
515 #if __XEN_INTERFACE_VERSION__ >= 0x0003020a
516 /*
517  * GNTTABOP_set_version: Request a particular version of the grant
518  * table shared table structure.  This operation can only be performed
519  * once in any given domain.  It must be performed before any grants
520  * are activated; otherwise, the domain will be stuck with version 1.
521  * The only defined versions are 1 and 2.
522  */
523 struct gnttab_set_version {
524     /* IN/OUT parameters */
525     uint32_t version;
526 };
527 typedef struct gnttab_set_version gnttab_set_version_t;
528 DEFINE_XEN_GUEST_HANDLE(gnttab_set_version_t);
529 
530 
531 /*
532  * GNTTABOP_get_status_frames: Get the list of frames used to store grant
533  * status for <dom>. In grant format version 2, the status is separated
534  * from the other shared grant fields to allow more efficient synchronization
535  * using barriers instead of atomic cmpexch operations.
536  * <nr_frames> specify the size of vector <frame_list>.
537  * The frame addresses are returned in the <frame_list>.
538  * Only <nr_frames> addresses are returned, even if the table is larger.
539  * NOTES:
540  *  1. <dom> may be specified as DOMID_SELF.
541  *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
542  */
543 struct gnttab_get_status_frames {
544     /* IN parameters. */
545     uint32_t nr_frames;
546     domid_t  dom;
547     /* OUT parameters. */
548     int16_t  status;              /* => enum grant_status */
549     XEN_GUEST_HANDLE(uint64_t) frame_list;
550 };
551 typedef struct gnttab_get_status_frames gnttab_get_status_frames_t;
552 DEFINE_XEN_GUEST_HANDLE(gnttab_get_status_frames_t);
553 
554 /*
555  * GNTTABOP_get_version: Get the grant table version which is in
556  * effect for domain <dom>.
557  */
558 struct gnttab_get_version {
559     /* IN parameters */
560     domid_t dom;
561     uint16_t pad;
562     /* OUT parameters */
563     uint32_t version;
564 };
565 typedef struct gnttab_get_version gnttab_get_version_t;
566 DEFINE_XEN_GUEST_HANDLE(gnttab_get_version_t);
567 
568 /*
569  * GNTTABOP_swap_grant_ref: Swap the contents of two grant entries.
570  */
571 struct gnttab_swap_grant_ref {
572     /* IN parameters */
573     grant_ref_t ref_a;
574     grant_ref_t ref_b;
575     /* OUT parameters */
576     int16_t status;             /* => enum grant_status */
577 };
578 typedef struct gnttab_swap_grant_ref gnttab_swap_grant_ref_t;
579 DEFINE_XEN_GUEST_HANDLE(gnttab_swap_grant_ref_t);
580 
581 /*
582  * Issue one or more cache maintenance operations on a portion of a
583  * page granted to the calling domain by a foreign domain.
584  */
585 struct gnttab_cache_flush {
586     union {
587         uint64_t dev_bus_addr;
588         grant_ref_t ref;
589     } a;
590     uint16_t offset; /* offset from start of grant */
591     uint16_t length; /* size within the grant */
592 #define GNTTAB_CACHE_CLEAN          (1u<<0)
593 #define GNTTAB_CACHE_INVAL          (1u<<1)
594 #define GNTTAB_CACHE_SOURCE_GREF    (1u<<31)
595     uint32_t op;
596 };
597 typedef struct gnttab_cache_flush gnttab_cache_flush_t;
598 DEFINE_XEN_GUEST_HANDLE(gnttab_cache_flush_t);
599 
600 #endif /* __XEN_INTERFACE_VERSION__ */
601 
602 /*
603  * Bitfield values for gnttab_map_grant_ref.flags.
604  */
605  /* Map the grant entry for access by I/O devices. */
606 #define _GNTMAP_device_map      (0)
607 #define GNTMAP_device_map       (1<<_GNTMAP_device_map)
608  /* Map the grant entry for access by host CPUs. */
609 #define _GNTMAP_host_map        (1)
610 #define GNTMAP_host_map         (1<<_GNTMAP_host_map)
611  /* Accesses to the granted frame will be restricted to read-only access. */
612 #define _GNTMAP_readonly        (2)
613 #define GNTMAP_readonly         (1<<_GNTMAP_readonly)
614  /*
615   * GNTMAP_host_map subflag:
616   *  0 => The host mapping is usable only by the guest OS.
617   *  1 => The host mapping is usable by guest OS + current application.
618   */
619 #define _GNTMAP_application_map (3)
620 #define GNTMAP_application_map  (1<<_GNTMAP_application_map)
621 
622  /*
623   * GNTMAP_contains_pte subflag:
624   *  0 => This map request contains a host virtual address.
625   *  1 => This map request contains the machine addess of the PTE to update.
626   */
627 #define _GNTMAP_contains_pte    (4)
628 #define GNTMAP_contains_pte     (1<<_GNTMAP_contains_pte)
629 
630 #define _GNTMAP_can_fail        (5)
631 #define GNTMAP_can_fail         (1<<_GNTMAP_can_fail)
632 
633 /*
634  * Bits to be placed in guest kernel available PTE bits (architecture
635  * dependent; only supported when XENFEAT_gnttab_map_avail_bits is set).
636  */
637 #define _GNTMAP_guest_avail0    (16)
638 #define GNTMAP_guest_avail_mask ((uint32_t)~0 << _GNTMAP_guest_avail0)
639 
640 /*
641  * Values for error status returns. All errors are -ve.
642  */
643 /* ` enum grant_status { */
644 #define GNTST_okay             (0)  /* Normal return.                        */
645 #define GNTST_general_error    (-1) /* General undefined error.              */
646 #define GNTST_bad_domain       (-2) /* Unrecognsed domain id.                */
647 #define GNTST_bad_gntref       (-3) /* Unrecognised or inappropriate gntref. */
648 #define GNTST_bad_handle       (-4) /* Unrecognised or inappropriate handle. */
649 #define GNTST_bad_virt_addr    (-5) /* Inappropriate virtual address to map. */
650 #define GNTST_bad_dev_addr     (-6) /* Inappropriate device address to unmap.*/
651 #define GNTST_no_device_space  (-7) /* Out of space in I/O MMU.              */
652 #define GNTST_permission_denied (-8) /* Not enough privilege for operation.  */
653 #define GNTST_bad_page         (-9) /* Specified page was invalid for op.    */
654 #define GNTST_bad_copy_arg    (-10) /* copy arguments cross page boundary.   */
655 #define GNTST_address_too_big (-11) /* transfer page address too large.      */
656 #define GNTST_eagain          (-12) /* Operation not done; try again.        */
657 /* ` } */
658 
659 #define GNTTABOP_error_msgs {                   \
660     "okay",                                     \
661     "undefined error",                          \
662     "unrecognised domain id",                   \
663     "invalid grant reference",                  \
664     "invalid mapping handle",                   \
665     "invalid virtual address",                  \
666     "invalid device address",                   \
667     "no spare translation slot in the I/O MMU", \
668     "permission denied",                        \
669     "bad page",                                 \
670     "copy arguments cross page boundary",       \
671     "page address size too large",              \
672     "operation not done; try again"             \
673 }
674 
675 #endif /* __XEN_PUBLIC_GRANT_TABLE_H__ */
676 
677 /*
678  * Local variables:
679  * mode: C
680  * c-file-style: "BSD"
681  * c-basic-offset: 4
682  * tab-width: 4
683  * indent-tabs-mode: nil
684  * End:
685  */
686