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 largely for
125  * backwards compatibility.  New guests are recommended to support using
126  * version 2 to overcome version 1 limitations, but to default to version 1.
127  */
128 #if __XEN_INTERFACE_VERSION__ < 0x0003020a
129 #define grant_entry_v1 grant_entry
130 #define grant_entry_v1_t grant_entry_t
131 #endif
132 struct grant_entry_v1 {
133     /* GTF_xxx: various type and flag information.  [XEN,GST] */
134     uint16_t flags;
135     /* The domain being granted foreign privileges. [GST] */
136     domid_t  domid;
137     /*
138      * GTF_permit_access: GFN that @domid is allowed to map and access. [GST]
139      * GTF_accept_transfer: GFN that @domid is allowed to transfer into. [GST]
140      * GTF_transfer_completed: MFN whose ownership transferred by @domid
141      *                         (non-translated guests only). [XEN]
142      */
143     uint32_t frame;
144 };
145 typedef struct grant_entry_v1 grant_entry_v1_t;
146 
147 /* The first few grant table entries will be preserved across grant table
148  * version changes and may be pre-populated at domain creation by tools.
149  */
150 #define GNTTAB_NR_RESERVED_ENTRIES     8
151 #define GNTTAB_RESERVED_CONSOLE        0
152 #define GNTTAB_RESERVED_XENSTORE       1
153 
154 /*
155  * Type of grant entry.
156  *  GTF_invalid: This grant entry grants no privileges.
157  *  GTF_permit_access: Allow @domid to map/access @frame.
158  *  GTF_accept_transfer: Allow @domid to transfer ownership of one page frame
159  *                       to this guest. Xen writes the page number to @frame.
160  *  GTF_transitive: Allow @domid to transitively access a subrange of
161  *                  @trans_grant in @trans_domid.  No mappings are allowed.
162  */
163 #define GTF_invalid         (0U<<0)
164 #define GTF_permit_access   (1U<<0)
165 #define GTF_accept_transfer (2U<<0)
166 #define GTF_transitive      (3U<<0)
167 #define GTF_type_mask       (3U<<0)
168 
169 /*
170  * Subflags for GTF_permit_access and GTF_transitive.
171  *  GTF_readonly: Restrict @domid to read-only mappings and accesses. [GST]
172  *  GTF_reading: Grant entry is currently mapped for reading by @domid. [XEN]
173  *  GTF_writing: Grant entry is currently mapped for writing by @domid. [XEN]
174  * Further subflags for GTF_permit_access only.
175  *  GTF_PAT, GTF_PWT, GTF_PCD: (x86) cache attribute flags to be used for
176  *                             mappings of the grant [GST]
177  *  GTF_sub_page: Grant access to only a subrange of the page.  @domid
178  *                will only be allowed to copy from the grant, and not
179  *                map it. [GST]
180  */
181 #define _GTF_readonly       (2)
182 #define GTF_readonly        (1U<<_GTF_readonly)
183 #define _GTF_reading        (3)
184 #define GTF_reading         (1U<<_GTF_reading)
185 #define _GTF_writing        (4)
186 #define GTF_writing         (1U<<_GTF_writing)
187 #define _GTF_PWT            (5)
188 #define GTF_PWT             (1U<<_GTF_PWT)
189 #define _GTF_PCD            (6)
190 #define GTF_PCD             (1U<<_GTF_PCD)
191 #define _GTF_PAT            (7)
192 #define GTF_PAT             (1U<<_GTF_PAT)
193 #define _GTF_sub_page       (8)
194 #define GTF_sub_page        (1U<<_GTF_sub_page)
195 
196 /*
197  * Subflags for GTF_accept_transfer:
198  *  GTF_transfer_committed: Xen sets this flag to indicate that it is committed
199  *      to transferring ownership of a page frame. When a guest sees this flag
200  *      it must /not/ modify the grant entry until GTF_transfer_completed is
201  *      set by Xen.
202  *  GTF_transfer_completed: It is safe for the guest to spin-wait on this flag
203  *      after reading GTF_transfer_committed. Xen will always write the frame
204  *      address, followed by ORing this flag, in a timely manner.
205  */
206 #define _GTF_transfer_committed (2)
207 #define GTF_transfer_committed  (1U<<_GTF_transfer_committed)
208 #define _GTF_transfer_completed (3)
209 #define GTF_transfer_completed  (1U<<_GTF_transfer_completed)
210 
211 /*
212  * Version 2 grant table entries.  These fulfil the same role as
213  * version 1 entries, but can represent more complicated operations.
214  * Any given domain will have either a version 1 or a version 2 table,
215  * and every entry in the table will be the same version.
216  *
217  * The interface by which domains use grant references does not depend
218  * on the grant table version in use by the other domain.
219  */
220 #if __XEN_INTERFACE_VERSION__ >= 0x0003020a
221 /*
222  * Version 1 and version 2 grant entries share a common prefix.  The
223  * fields of the prefix are documented as part of struct
224  * grant_entry_v1.
225  */
226 struct grant_entry_header {
227     uint16_t flags;
228     domid_t  domid;
229 };
230 typedef struct grant_entry_header grant_entry_header_t;
231 
232 /*
233  * Version 2 of the grant entry structure.
234  */
235 union grant_entry_v2 {
236     grant_entry_header_t hdr;
237 
238     /*
239      * This member is used for V1-style full page grants, where either:
240      *
241      * -- hdr.type is GTF_accept_transfer, or
242      * -- hdr.type is GTF_permit_access and GTF_sub_page is not set.
243      *
244      * In that case, the frame field has the same semantics as the
245      * field of the same name in the V1 entry structure.
246      */
247     struct {
248         grant_entry_header_t hdr;
249         uint32_t pad0;
250         uint64_t frame;
251     } full_page;
252 
253     /*
254      * If the grant type is GTF_grant_access and GTF_sub_page is set,
255      * @domid is allowed to access bytes [@page_off,@page_off+@length)
256      * in frame @frame.
257      */
258     struct {
259         grant_entry_header_t hdr;
260         uint16_t page_off;
261         uint16_t length;
262         uint64_t frame;
263     } sub_page;
264 
265     /*
266      * If the grant is GTF_transitive, @domid is allowed to use the
267      * grant @gref in domain @trans_domid, as if it was the local
268      * domain.  Obviously, the transitive access must be compatible
269      * with the original grant.
270      *
271      * The current version of Xen does not allow transitive grants
272      * to be mapped.
273      */
274     struct {
275         grant_entry_header_t hdr;
276         domid_t trans_domid;
277         uint16_t pad0;
278         grant_ref_t gref;
279     } transitive;
280 
281     uint32_t __spacer[4]; /* Pad to a power of two */
282 };
283 typedef union grant_entry_v2 grant_entry_v2_t;
284 
285 typedef uint16_t grant_status_t;
286 
287 #endif /* __XEN_INTERFACE_VERSION__ */
288 
289 /***********************************
290  * GRANT TABLE QUERIES AND USES
291  */
292 
293 /* ` enum neg_errnoval
294  * ` HYPERVISOR_grant_table_op(enum grant_table_op cmd,
295  * `                           void *args,
296  * `                           unsigned int count)
297  * `
298  *
299  * @args points to an array of a per-command data structure. The array
300  * has @count members
301  */
302 
303 /* ` enum grant_table_op { // GNTTABOP_* => struct gnttab_* */
304 #define GNTTABOP_map_grant_ref        0
305 #define GNTTABOP_unmap_grant_ref      1
306 #define GNTTABOP_setup_table          2
307 #define GNTTABOP_dump_table           3
308 #define GNTTABOP_transfer             4
309 #define GNTTABOP_copy                 5
310 #define GNTTABOP_query_size           6
311 #define GNTTABOP_unmap_and_replace    7
312 #if __XEN_INTERFACE_VERSION__ >= 0x0003020a
313 #define GNTTABOP_set_version          8
314 #define GNTTABOP_get_status_frames    9
315 #define GNTTABOP_get_version          10
316 #define GNTTABOP_swap_grant_ref	      11
317 #define GNTTABOP_cache_flush	      12
318 #endif /* __XEN_INTERFACE_VERSION__ */
319 /* ` } */
320 
321 /*
322  * Handle to track a mapping created via a grant reference.
323  */
324 typedef uint32_t grant_handle_t;
325 
326 /*
327  * GNTTABOP_map_grant_ref: Map the grant entry (<dom>,<ref>) for access
328  * by devices and/or host CPUs. If successful, <handle> is a tracking number
329  * that must be presented later to destroy the mapping(s). On error, <status>
330  * is a negative status code.
331  * NOTES:
332  *  1. If GNTMAP_device_map is specified then <dev_bus_addr> is the address
333  *     via which I/O devices may access the granted frame.
334  *  2. If GNTMAP_host_map is specified then a mapping will be added at
335  *     either a host virtual address in the current address space, or at
336  *     a PTE at the specified machine address.  The type of mapping to
337  *     perform is selected through the GNTMAP_contains_pte flag, and the
338  *     address is specified in <host_addr>.
339  *  3. Mappings should only be destroyed via GNTTABOP_unmap_grant_ref. If a
340  *     host mapping is destroyed by other means then it is *NOT* guaranteed
341  *     to be accounted to the correct grant reference!
342  */
343 struct gnttab_map_grant_ref {
344     /* IN parameters. */
345     uint64_t host_addr;
346     uint32_t flags;               /* GNTMAP_* */
347     grant_ref_t ref;
348     domid_t  dom;
349     /* OUT parameters. */
350     int16_t  status;              /* => enum grant_status */
351     grant_handle_t handle;
352     uint64_t dev_bus_addr;
353 };
354 typedef struct gnttab_map_grant_ref gnttab_map_grant_ref_t;
355 DEFINE_XEN_GUEST_HANDLE(gnttab_map_grant_ref_t);
356 
357 /*
358  * GNTTABOP_unmap_grant_ref: Destroy one or more grant-reference mappings
359  * tracked by <handle>. If <host_addr> or <dev_bus_addr> is zero, that
360  * field is ignored. If non-zero, they must refer to a device/host mapping
361  * that is tracked by <handle>
362  * NOTES:
363  *  1. The call may fail in an undefined manner if either mapping is not
364  *     tracked by <handle>.
365  *  3. After executing a batch of unmaps, it is guaranteed that no stale
366  *     mappings will remain in the device or host TLBs.
367  */
368 struct gnttab_unmap_grant_ref {
369     /* IN parameters. */
370     uint64_t host_addr;
371     uint64_t dev_bus_addr;
372     grant_handle_t handle;
373     /* OUT parameters. */
374     int16_t  status;              /* => enum grant_status */
375 };
376 typedef struct gnttab_unmap_grant_ref gnttab_unmap_grant_ref_t;
377 DEFINE_XEN_GUEST_HANDLE(gnttab_unmap_grant_ref_t);
378 
379 /*
380  * GNTTABOP_setup_table: Set up a grant table for <dom> comprising at least
381  * <nr_frames> pages. The frame addresses are written to the <frame_list>.
382  * Only <nr_frames> addresses are written, even if the table is larger.
383  * NOTES:
384  *  1. <dom> may be specified as DOMID_SELF.
385  *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
386  *  3. Xen may not support more than a single grant-table page per domain.
387  */
388 struct gnttab_setup_table {
389     /* IN parameters. */
390     domid_t  dom;
391     uint32_t nr_frames;
392     /* OUT parameters. */
393     int16_t  status;              /* => enum grant_status */
394 #if __XEN_INTERFACE_VERSION__ < 0x00040300
395     XEN_GUEST_HANDLE(ulong) frame_list;
396 #else
397     XEN_GUEST_HANDLE(xen_pfn_t) frame_list;
398 #endif
399 };
400 typedef struct gnttab_setup_table gnttab_setup_table_t;
401 DEFINE_XEN_GUEST_HANDLE(gnttab_setup_table_t);
402 
403 /*
404  * GNTTABOP_dump_table: Dump the contents of the grant table to the
405  * xen console. Debugging use only.
406  */
407 struct gnttab_dump_table {
408     /* IN parameters. */
409     domid_t dom;
410     /* OUT parameters. */
411     int16_t status;               /* => enum grant_status */
412 };
413 typedef struct gnttab_dump_table gnttab_dump_table_t;
414 DEFINE_XEN_GUEST_HANDLE(gnttab_dump_table_t);
415 
416 /*
417  * GNTTABOP_transfer: Transfer <frame> to a foreign domain. The foreign domain
418  * has previously registered its interest in the transfer via <domid, ref>.
419  *
420  * Note that, even if the transfer fails, the specified page no longer belongs
421  * to the calling domain *unless* the error is GNTST_bad_page.
422  *
423  * Note further that only PV guests can use this operation.
424  */
425 struct gnttab_transfer {
426     /* IN parameters. */
427     xen_pfn_t     mfn;
428     domid_t       domid;
429     grant_ref_t   ref;
430     /* OUT parameters. */
431     int16_t       status;
432 };
433 typedef struct gnttab_transfer gnttab_transfer_t;
434 DEFINE_XEN_GUEST_HANDLE(gnttab_transfer_t);
435 
436 
437 /*
438  * GNTTABOP_copy: Hypervisor based copy
439  * source and destinations can be eithers MFNs or, for foreign domains,
440  * grant references. the foreign domain has to grant read/write access
441  * in its grant table.
442  *
443  * The flags specify what type source and destinations are (either MFN
444  * or grant reference).
445  *
446  * Note that this can also be used to copy data between two domains
447  * via a third party if the source and destination domains had previously
448  * grant appropriate access to their pages to the third party.
449  *
450  * source_offset specifies an offset in the source frame, dest_offset
451  * the offset in the target frame and  len specifies the number of
452  * bytes to be copied.
453  */
454 
455 #define _GNTCOPY_source_gref      (0)
456 #define GNTCOPY_source_gref       (1<<_GNTCOPY_source_gref)
457 #define _GNTCOPY_dest_gref        (1)
458 #define GNTCOPY_dest_gref         (1<<_GNTCOPY_dest_gref)
459 
460 struct gnttab_copy {
461     /* IN parameters. */
462     struct gnttab_copy_ptr {
463         union {
464             grant_ref_t ref;
465             xen_pfn_t   gmfn;
466         } u;
467         domid_t  domid;
468         uint16_t offset;
469     } source, dest;
470     uint16_t      len;
471     uint16_t      flags;          /* GNTCOPY_* */
472     /* OUT parameters. */
473     int16_t       status;
474 };
475 typedef struct gnttab_copy  gnttab_copy_t;
476 DEFINE_XEN_GUEST_HANDLE(gnttab_copy_t);
477 
478 /*
479  * GNTTABOP_query_size: Query the current and maximum sizes of the shared
480  * grant table.
481  * NOTES:
482  *  1. <dom> may be specified as DOMID_SELF.
483  *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
484  */
485 struct gnttab_query_size {
486     /* IN parameters. */
487     domid_t  dom;
488     /* OUT parameters. */
489     uint32_t nr_frames;
490     uint32_t max_nr_frames;
491     int16_t  status;              /* => enum grant_status */
492 };
493 typedef struct gnttab_query_size gnttab_query_size_t;
494 DEFINE_XEN_GUEST_HANDLE(gnttab_query_size_t);
495 
496 /*
497  * GNTTABOP_unmap_and_replace: Destroy one or more grant-reference mappings
498  * tracked by <handle> but atomically replace the page table entry with one
499  * pointing to the machine address under <new_addr>.  <new_addr> will be
500  * redirected to the null entry.
501  * NOTES:
502  *  1. The call may fail in an undefined manner if either mapping is not
503  *     tracked by <handle>.
504  *  2. After executing a batch of unmaps, it is guaranteed that no stale
505  *     mappings will remain in the device or host TLBs.
506  */
507 struct gnttab_unmap_and_replace {
508     /* IN parameters. */
509     uint64_t host_addr;
510     uint64_t new_addr;
511     grant_handle_t handle;
512     /* OUT parameters. */
513     int16_t  status;              /* => enum grant_status */
514 };
515 typedef struct gnttab_unmap_and_replace gnttab_unmap_and_replace_t;
516 DEFINE_XEN_GUEST_HANDLE(gnttab_unmap_and_replace_t);
517 
518 #if __XEN_INTERFACE_VERSION__ >= 0x0003020a
519 /*
520  * GNTTABOP_set_version: Request a particular version of the grant
521  * table shared table structure.  This operation may be used to toggle
522  * between different versions, but must be performed while no grants
523  * are active.  The only defined versions are 1 and 2.
524  */
525 struct gnttab_set_version {
526     /* IN/OUT parameters */
527     uint32_t version;
528 };
529 typedef struct gnttab_set_version gnttab_set_version_t;
530 DEFINE_XEN_GUEST_HANDLE(gnttab_set_version_t);
531 
532 
533 /*
534  * GNTTABOP_get_status_frames: Get the list of frames used to store grant
535  * status for <dom>. In grant format version 2, the status is separated
536  * from the other shared grant fields to allow more efficient synchronization
537  * using barriers instead of atomic cmpexch operations.
538  * <nr_frames> specify the size of vector <frame_list>.
539  * The frame addresses are returned in the <frame_list>.
540  * Only <nr_frames> addresses are returned, even if the table is larger.
541  * NOTES:
542  *  1. <dom> may be specified as DOMID_SELF.
543  *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
544  */
545 struct gnttab_get_status_frames {
546     /* IN parameters. */
547     uint32_t nr_frames;
548     domid_t  dom;
549     /* OUT parameters. */
550     int16_t  status;              /* => enum grant_status */
551     XEN_GUEST_HANDLE(uint64_t) frame_list;
552 };
553 typedef struct gnttab_get_status_frames gnttab_get_status_frames_t;
554 DEFINE_XEN_GUEST_HANDLE(gnttab_get_status_frames_t);
555 
556 /*
557  * GNTTABOP_get_version: Get the grant table version which is in
558  * effect for domain <dom>.
559  */
560 struct gnttab_get_version {
561     /* IN parameters */
562     domid_t dom;
563     uint16_t pad;
564     /* OUT parameters */
565     uint32_t version;
566 };
567 typedef struct gnttab_get_version gnttab_get_version_t;
568 DEFINE_XEN_GUEST_HANDLE(gnttab_get_version_t);
569 
570 /*
571  * GNTTABOP_swap_grant_ref: Swap the contents of two grant entries.
572  */
573 struct gnttab_swap_grant_ref {
574     /* IN parameters */
575     grant_ref_t ref_a;
576     grant_ref_t ref_b;
577     /* OUT parameters */
578     int16_t status;             /* => enum grant_status */
579 };
580 typedef struct gnttab_swap_grant_ref gnttab_swap_grant_ref_t;
581 DEFINE_XEN_GUEST_HANDLE(gnttab_swap_grant_ref_t);
582 
583 /*
584  * Issue one or more cache maintenance operations on a portion of a
585  * page granted to the calling domain by a foreign domain.
586  */
587 struct gnttab_cache_flush {
588     union {
589         uint64_t dev_bus_addr;
590         grant_ref_t ref;
591     } a;
592     uint16_t offset; /* offset from start of grant */
593     uint16_t length; /* size within the grant */
594 #define GNTTAB_CACHE_CLEAN          (1u<<0)
595 #define GNTTAB_CACHE_INVAL          (1u<<1)
596 #define GNTTAB_CACHE_SOURCE_GREF    (1u<<31)
597     uint32_t op;
598 };
599 typedef struct gnttab_cache_flush gnttab_cache_flush_t;
600 DEFINE_XEN_GUEST_HANDLE(gnttab_cache_flush_t);
601 
602 #endif /* __XEN_INTERFACE_VERSION__ */
603 
604 /*
605  * Bitfield values for gnttab_map_grant_ref.flags.
606  */
607  /* Map the grant entry for access by I/O devices. */
608 #define _GNTMAP_device_map      (0)
609 #define GNTMAP_device_map       (1<<_GNTMAP_device_map)
610  /* Map the grant entry for access by host CPUs. */
611 #define _GNTMAP_host_map        (1)
612 #define GNTMAP_host_map         (1<<_GNTMAP_host_map)
613  /* Accesses to the granted frame will be restricted to read-only access. */
614 #define _GNTMAP_readonly        (2)
615 #define GNTMAP_readonly         (1<<_GNTMAP_readonly)
616  /*
617   * GNTMAP_host_map subflag:
618   *  0 => The host mapping is usable only by the guest OS.
619   *  1 => The host mapping is usable by guest OS + current application.
620   */
621 #define _GNTMAP_application_map (3)
622 #define GNTMAP_application_map  (1<<_GNTMAP_application_map)
623 
624  /*
625   * GNTMAP_contains_pte subflag:
626   *  0 => This map request contains a host virtual address.
627   *  1 => This map request contains the machine addess of the PTE to update.
628   */
629 #define _GNTMAP_contains_pte    (4)
630 #define GNTMAP_contains_pte     (1<<_GNTMAP_contains_pte)
631 
632 /*
633  * Bits to be placed in guest kernel available PTE bits (architecture
634  * dependent; only supported when XENFEAT_gnttab_map_avail_bits is set).
635  */
636 #define _GNTMAP_guest_avail0    (16)
637 #define GNTMAP_guest_avail_mask ((uint32_t)~0 << _GNTMAP_guest_avail0)
638 
639 /*
640  * Values for error status returns. All errors are -ve.
641  */
642 /* ` enum grant_status { */
643 #define GNTST_okay             (0)  /* Normal return.                        */
644 #define GNTST_general_error    (-1) /* General undefined error.              */
645 #define GNTST_bad_domain       (-2) /* Unrecognsed domain id.                */
646 #define GNTST_bad_gntref       (-3) /* Unrecognised or inappropriate gntref. */
647 #define GNTST_bad_handle       (-4) /* Unrecognised or inappropriate handle. */
648 #define GNTST_bad_virt_addr    (-5) /* Inappropriate virtual address to map. */
649 #define GNTST_bad_dev_addr     (-6) /* Inappropriate device address to unmap.*/
650 #define GNTST_no_device_space  (-7) /* Out of space in I/O MMU.              */
651 #define GNTST_permission_denied (-8) /* Not enough privilege for operation.  */
652 #define GNTST_bad_page         (-9) /* Specified page was invalid for op.    */
653 #define GNTST_bad_copy_arg    (-10) /* copy arguments cross page boundary.   */
654 #define GNTST_address_too_big (-11) /* transfer page address too large.      */
655 #define GNTST_eagain          (-12) /* Operation not done; try again.        */
656 #define GNTST_no_space        (-13) /* Out of space (handles etc).           */
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     "out of space",                             \
674 }
675 
676 #endif /* __XEN_PUBLIC_GRANT_TABLE_H__ */
677 
678 /*
679  * Local variables:
680  * mode: C
681  * c-file-style: "BSD"
682  * c-basic-offset: 4
683  * tab-width: 4
684  * indent-tabs-mode: nil
685  * End:
686  */
687