ia64/xen-unstable

view xen/include/public/grant_table.h @ 16407:2e5d922b7ee3

xen: Allow granting of foreign access to iomem pages, and with
arbitrary cache attributes.
Signed-off-by: Kieran Mansley <kmansley@solarflare.com>
Signed-off-by: Keir Fraser <keir.fraser@eu.citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Tue Nov 20 17:26:48 2007 +0000 (2007-11-20)
parents 1f7a6456c330
children baf90ee3c1da
line source
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 */
28 #ifndef __XEN_PUBLIC_GRANT_TABLE_H__
29 #define __XEN_PUBLIC_GRANT_TABLE_H__
32 /***********************************
33 * GRANT TABLE REPRESENTATION
34 */
36 /* Some rough guidelines on accessing and updating grant-table entries
37 * in a concurrency-safe manner. For more information, Linux contains a
38 * reference implementation for guest OSes (arch/xen/kernel/grant_table.c).
39 *
40 * NB. WMB is a no-op on current-generation x86 processors. However, a
41 * compiler barrier will still be required.
42 *
43 * Introducing a valid entry into the grant table:
44 * 1. Write ent->domid.
45 * 2. Write ent->frame:
46 * GTF_permit_access: Frame to which access is permitted.
47 * GTF_accept_transfer: Pseudo-phys frame slot being filled by new
48 * frame, or zero if none.
49 * 3. Write memory barrier (WMB).
50 * 4. Write ent->flags, inc. valid type.
51 *
52 * Invalidating an unused GTF_permit_access entry:
53 * 1. flags = ent->flags.
54 * 2. Observe that !(flags & (GTF_reading|GTF_writing)).
55 * 3. Check result of SMP-safe CMPXCHG(&ent->flags, flags, 0).
56 * NB. No need for WMB as reuse of entry is control-dependent on success of
57 * step 3, and all architectures guarantee ordering of ctrl-dep writes.
58 *
59 * Invalidating an in-use GTF_permit_access entry:
60 * This cannot be done directly. Request assistance from the domain controller
61 * which can set a timeout on the use of a grant entry and take necessary
62 * action. (NB. This is not yet implemented!).
63 *
64 * Invalidating an unused GTF_accept_transfer entry:
65 * 1. flags = ent->flags.
66 * 2. Observe that !(flags & GTF_transfer_committed). [*]
67 * 3. Check result of SMP-safe CMPXCHG(&ent->flags, flags, 0).
68 * NB. No need for WMB as reuse of entry is control-dependent on success of
69 * step 3, and all architectures guarantee ordering of ctrl-dep writes.
70 * [*] If GTF_transfer_committed is set then the grant entry is 'committed'.
71 * The guest must /not/ modify the grant entry until the address of the
72 * transferred frame is written. It is safe for the guest to spin waiting
73 * for this to occur (detect by observing GTF_transfer_completed in
74 * ent->flags).
75 *
76 * Invalidating a committed GTF_accept_transfer entry:
77 * 1. Wait for (ent->flags & GTF_transfer_completed).
78 *
79 * Changing a GTF_permit_access from writable to read-only:
80 * Use SMP-safe CMPXCHG to set GTF_readonly, while checking !GTF_writing.
81 *
82 * Changing a GTF_permit_access from read-only to writable:
83 * Use SMP-safe bit-setting instruction.
84 */
86 /*
87 * A grant table comprises a packed array of grant entries in one or more
88 * page frames shared between Xen and a guest.
89 * [XEN]: This field is written by Xen and read by the sharing guest.
90 * [GST]: This field is written by the guest and read by Xen.
91 */
92 struct grant_entry {
93 /* GTF_xxx: various type and flag information. [XEN,GST] */
94 uint16_t flags;
95 /* The domain being granted foreign privileges. [GST] */
96 domid_t domid;
97 /*
98 * GTF_permit_access: Frame that @domid is allowed to map and access. [GST]
99 * GTF_accept_transfer: Frame whose ownership transferred by @domid. [XEN]
100 */
101 uint32_t frame;
102 };
103 typedef struct grant_entry grant_entry_t;
105 /*
106 * Type of grant entry.
107 * GTF_invalid: This grant entry grants no privileges.
108 * GTF_permit_access: Allow @domid to map/access @frame.
109 * GTF_accept_transfer: Allow @domid to transfer ownership of one page frame
110 * to this guest. Xen writes the page number to @frame.
111 */
112 #define GTF_invalid (0U<<0)
113 #define GTF_permit_access (1U<<0)
114 #define GTF_accept_transfer (2U<<0)
115 #define GTF_type_mask (3U<<0)
117 /*
118 * Subflags for GTF_permit_access.
119 * GTF_readonly: Restrict @domid to read-only mappings and accesses. [GST]
120 * GTF_reading: Grant entry is currently mapped for reading by @domid. [XEN]
121 * GTF_writing: Grant entry is currently mapped for writing by @domid. [XEN]
122 * GTF_PAT, GTF_PWT, GTF_PCD: (x86) cache attribute flags for the grant [GST]
123 */
124 #define _GTF_readonly (2)
125 #define GTF_readonly (1U<<_GTF_readonly)
126 #define _GTF_reading (3)
127 #define GTF_reading (1U<<_GTF_reading)
128 #define _GTF_writing (4)
129 #define GTF_writing (1U<<_GTF_writing)
130 #define _GTF_PWT (5)
131 #define GTF_PWT (1U<<_GTF_PWT)
132 #define _GTF_PCD (6)
133 #define GTF_PCD (1U<<_GTF_PCD)
134 #define _GTF_PAT (7)
135 #define GTF_PAT (1U<<_GTF_PAT)
137 /*
138 * Subflags for GTF_accept_transfer:
139 * GTF_transfer_committed: Xen sets this flag to indicate that it is committed
140 * to transferring ownership of a page frame. When a guest sees this flag
141 * it must /not/ modify the grant entry until GTF_transfer_completed is
142 * set by Xen.
143 * GTF_transfer_completed: It is safe for the guest to spin-wait on this flag
144 * after reading GTF_transfer_committed. Xen will always write the frame
145 * address, followed by ORing this flag, in a timely manner.
146 */
147 #define _GTF_transfer_committed (2)
148 #define GTF_transfer_committed (1U<<_GTF_transfer_committed)
149 #define _GTF_transfer_completed (3)
150 #define GTF_transfer_completed (1U<<_GTF_transfer_completed)
153 /***********************************
154 * GRANT TABLE QUERIES AND USES
155 */
157 /*
158 * Reference to a grant entry in a specified domain's grant table.
159 */
160 typedef uint32_t grant_ref_t;
162 /*
163 * Handle to track a mapping created via a grant reference.
164 */
165 typedef uint32_t grant_handle_t;
167 /*
168 * GNTTABOP_map_grant_ref: Map the grant entry (<dom>,<ref>) for access
169 * by devices and/or host CPUs. If successful, <handle> is a tracking number
170 * that must be presented later to destroy the mapping(s). On error, <handle>
171 * is a negative status code.
172 * NOTES:
173 * 1. If GNTMAP_device_map is specified then <dev_bus_addr> is the address
174 * via which I/O devices may access the granted frame.
175 * 2. If GNTMAP_host_map is specified then a mapping will be added at
176 * either a host virtual address in the current address space, or at
177 * a PTE at the specified machine address. The type of mapping to
178 * perform is selected through the GNTMAP_contains_pte flag, and the
179 * address is specified in <host_addr>.
180 * 3. Mappings should only be destroyed via GNTTABOP_unmap_grant_ref. If a
181 * host mapping is destroyed by other means then it is *NOT* guaranteed
182 * to be accounted to the correct grant reference!
183 */
184 #define GNTTABOP_map_grant_ref 0
185 struct gnttab_map_grant_ref {
186 /* IN parameters. */
187 uint64_t host_addr;
188 uint32_t flags; /* GNTMAP_* */
189 grant_ref_t ref;
190 domid_t dom;
191 /* OUT parameters. */
192 int16_t status; /* GNTST_* */
193 grant_handle_t handle;
194 uint64_t dev_bus_addr;
195 };
196 typedef struct gnttab_map_grant_ref gnttab_map_grant_ref_t;
197 DEFINE_XEN_GUEST_HANDLE(gnttab_map_grant_ref_t);
199 /*
200 * GNTTABOP_unmap_grant_ref: Destroy one or more grant-reference mappings
201 * tracked by <handle>. If <host_addr> or <dev_bus_addr> is zero, that
202 * field is ignored. If non-zero, they must refer to a device/host mapping
203 * that is tracked by <handle>
204 * NOTES:
205 * 1. The call may fail in an undefined manner if either mapping is not
206 * tracked by <handle>.
207 * 3. After executing a batch of unmaps, it is guaranteed that no stale
208 * mappings will remain in the device or host TLBs.
209 */
210 #define GNTTABOP_unmap_grant_ref 1
211 struct gnttab_unmap_grant_ref {
212 /* IN parameters. */
213 uint64_t host_addr;
214 uint64_t dev_bus_addr;
215 grant_handle_t handle;
216 /* OUT parameters. */
217 int16_t status; /* GNTST_* */
218 };
219 typedef struct gnttab_unmap_grant_ref gnttab_unmap_grant_ref_t;
220 DEFINE_XEN_GUEST_HANDLE(gnttab_unmap_grant_ref_t);
222 /*
223 * GNTTABOP_setup_table: Set up a grant table for <dom> comprising at least
224 * <nr_frames> pages. The frame addresses are written to the <frame_list>.
225 * Only <nr_frames> addresses are written, even if the table is larger.
226 * NOTES:
227 * 1. <dom> may be specified as DOMID_SELF.
228 * 2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
229 * 3. Xen may not support more than a single grant-table page per domain.
230 */
231 #define GNTTABOP_setup_table 2
232 struct gnttab_setup_table {
233 /* IN parameters. */
234 domid_t dom;
235 uint32_t nr_frames;
236 /* OUT parameters. */
237 int16_t status; /* GNTST_* */
238 XEN_GUEST_HANDLE(ulong) frame_list;
239 };
240 typedef struct gnttab_setup_table gnttab_setup_table_t;
241 DEFINE_XEN_GUEST_HANDLE(gnttab_setup_table_t);
243 /*
244 * GNTTABOP_dump_table: Dump the contents of the grant table to the
245 * xen console. Debugging use only.
246 */
247 #define GNTTABOP_dump_table 3
248 struct gnttab_dump_table {
249 /* IN parameters. */
250 domid_t dom;
251 /* OUT parameters. */
252 int16_t status; /* GNTST_* */
253 };
254 typedef struct gnttab_dump_table gnttab_dump_table_t;
255 DEFINE_XEN_GUEST_HANDLE(gnttab_dump_table_t);
257 /*
258 * GNTTABOP_transfer_grant_ref: Transfer <frame> to a foreign domain. The
259 * foreign domain has previously registered its interest in the transfer via
260 * <domid, ref>.
261 *
262 * Note that, even if the transfer fails, the specified page no longer belongs
263 * to the calling domain *unless* the error is GNTST_bad_page.
264 */
265 #define GNTTABOP_transfer 4
266 struct gnttab_transfer {
267 /* IN parameters. */
268 xen_pfn_t mfn;
269 domid_t domid;
270 grant_ref_t ref;
271 /* OUT parameters. */
272 int16_t status;
273 };
274 typedef struct gnttab_transfer gnttab_transfer_t;
275 DEFINE_XEN_GUEST_HANDLE(gnttab_transfer_t);
278 /*
279 * GNTTABOP_copy: Hypervisor based copy
280 * source and destinations can be eithers MFNs or, for foreign domains,
281 * grant references. the foreign domain has to grant read/write access
282 * in its grant table.
283 *
284 * The flags specify what type source and destinations are (either MFN
285 * or grant reference).
286 *
287 * Note that this can also be used to copy data between two domains
288 * via a third party if the source and destination domains had previously
289 * grant appropriate access to their pages to the third party.
290 *
291 * source_offset specifies an offset in the source frame, dest_offset
292 * the offset in the target frame and len specifies the number of
293 * bytes to be copied.
294 */
296 #define _GNTCOPY_source_gref (0)
297 #define GNTCOPY_source_gref (1<<_GNTCOPY_source_gref)
298 #define _GNTCOPY_dest_gref (1)
299 #define GNTCOPY_dest_gref (1<<_GNTCOPY_dest_gref)
301 #define GNTTABOP_copy 5
302 typedef struct gnttab_copy {
303 /* IN parameters. */
304 struct {
305 union {
306 grant_ref_t ref;
307 xen_pfn_t gmfn;
308 } u;
309 domid_t domid;
310 uint16_t offset;
311 } source, dest;
312 uint16_t len;
313 uint16_t flags; /* GNTCOPY_* */
314 /* OUT parameters. */
315 int16_t status;
316 } gnttab_copy_t;
317 DEFINE_XEN_GUEST_HANDLE(gnttab_copy_t);
319 /*
320 * GNTTABOP_query_size: Query the current and maximum sizes of the shared
321 * grant table.
322 * NOTES:
323 * 1. <dom> may be specified as DOMID_SELF.
324 * 2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
325 */
326 #define GNTTABOP_query_size 6
327 struct gnttab_query_size {
328 /* IN parameters. */
329 domid_t dom;
330 /* OUT parameters. */
331 uint32_t nr_frames;
332 uint32_t max_nr_frames;
333 int16_t status; /* GNTST_* */
334 };
335 typedef struct gnttab_query_size gnttab_query_size_t;
336 DEFINE_XEN_GUEST_HANDLE(gnttab_query_size_t);
338 /*
339 * GNTTABOP_unmap_and_replace: Destroy one or more grant-reference mappings
340 * tracked by <handle> but atomically replace the page table entry with one
341 * pointing to the machine address under <new_addr>. <new_addr> will be
342 * redirected to the null entry.
343 * NOTES:
344 * 1. The call may fail in an undefined manner if either mapping is not
345 * tracked by <handle>.
346 * 2. After executing a batch of unmaps, it is guaranteed that no stale
347 * mappings will remain in the device or host TLBs.
348 */
349 #define GNTTABOP_unmap_and_replace 7
350 struct gnttab_unmap_and_replace {
351 /* IN parameters. */
352 uint64_t host_addr;
353 uint64_t new_addr;
354 grant_handle_t handle;
355 /* OUT parameters. */
356 int16_t status; /* GNTST_* */
357 };
358 typedef struct gnttab_unmap_and_replace gnttab_unmap_and_replace_t;
359 DEFINE_XEN_GUEST_HANDLE(gnttab_unmap_and_replace_t);
362 /*
363 * Bitfield values for update_pin_status.flags.
364 */
365 /* Map the grant entry for access by I/O devices. */
366 #define _GNTMAP_device_map (0)
367 #define GNTMAP_device_map (1<<_GNTMAP_device_map)
368 /* Map the grant entry for access by host CPUs. */
369 #define _GNTMAP_host_map (1)
370 #define GNTMAP_host_map (1<<_GNTMAP_host_map)
371 /* Accesses to the granted frame will be restricted to read-only access. */
372 #define _GNTMAP_readonly (2)
373 #define GNTMAP_readonly (1<<_GNTMAP_readonly)
374 /*
375 * GNTMAP_host_map subflag:
376 * 0 => The host mapping is usable only by the guest OS.
377 * 1 => The host mapping is usable by guest OS + current application.
378 */
379 #define _GNTMAP_application_map (3)
380 #define GNTMAP_application_map (1<<_GNTMAP_application_map)
382 /*
383 * GNTMAP_contains_pte subflag:
384 * 0 => This map request contains a host virtual address.
385 * 1 => This map request contains the machine addess of the PTE to update.
386 */
387 #define _GNTMAP_contains_pte (4)
388 #define GNTMAP_contains_pte (1<<_GNTMAP_contains_pte)
390 /*
391 * Values for error status returns. All errors are -ve.
392 */
393 #define GNTST_okay (0) /* Normal return. */
394 #define GNTST_general_error (-1) /* General undefined error. */
395 #define GNTST_bad_domain (-2) /* Unrecognsed domain id. */
396 #define GNTST_bad_gntref (-3) /* Unrecognised or inappropriate gntref. */
397 #define GNTST_bad_handle (-4) /* Unrecognised or inappropriate handle. */
398 #define GNTST_bad_virt_addr (-5) /* Inappropriate virtual address to map. */
399 #define GNTST_bad_dev_addr (-6) /* Inappropriate device address to unmap.*/
400 #define GNTST_no_device_space (-7) /* Out of space in I/O MMU. */
401 #define GNTST_permission_denied (-8) /* Not enough privilege for operation. */
402 #define GNTST_bad_page (-9) /* Specified page was invalid for op. */
403 #define GNTST_bad_copy_arg (-10) /* copy arguments cross page boundary */
405 #define GNTTABOP_error_msgs { \
406 "okay", \
407 "undefined error", \
408 "unrecognised domain id", \
409 "invalid grant reference", \
410 "invalid mapping handle", \
411 "invalid virtual address", \
412 "invalid device address", \
413 "no spare translation slot in the I/O MMU", \
414 "permission denied", \
415 "bad page", \
416 "copy arguments cross page boundary" \
417 }
419 #endif /* __XEN_PUBLIC_GRANT_TABLE_H__ */
421 /*
422 * Local variables:
423 * mode: C
424 * c-set-style: "BSD"
425 * c-basic-offset: 4
426 * tab-width: 4
427 * indent-tabs-mode: nil
428 * End:
429 */