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1.1 root 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:
32: /***********************************
33: * GRANT TABLE REPRESENTATION
34: */
35:
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: */
85:
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;
104:
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)
116:
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)
136:
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)
151:
152:
153: /***********************************
154: * GRANT TABLE QUERIES AND USES
155: */
156:
157: /*
158: * Reference to a grant entry in a specified domain's grant table.
159: */
160: typedef uint32_t grant_ref_t;
161:
162: /*
163: * Handle to track a mapping created via a grant reference.
164: */
165: typedef uint32_t grant_handle_t;
166:
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);
198:
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);
221:
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);
242:
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);
256:
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);
276:
277:
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: */
295:
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)
300:
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);
318:
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);
337:
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);
360:
361:
362: /*
363: * Bitfield values for gnttab_map_grant_ref.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)
381:
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)
389:
390: /*
391: * Bits to be placed in guest kernel available PTE bits (architecture
392: * dependent; only supported when XENFEAT_gnttab_map_avail_bits is set).
393: */
394: #define _GNTMAP_guest_avail0 (16)
395: #define GNTMAP_guest_avail_mask ((uint32_t)~0 << _GNTMAP_guest_avail0)
396:
397: /*
398: * Values for error status returns. All errors are -ve.
399: */
400: #define GNTST_okay (0) /* Normal return. */
401: #define GNTST_general_error (-1) /* General undefined error. */
402: #define GNTST_bad_domain (-2) /* Unrecognsed domain id. */
403: #define GNTST_bad_gntref (-3) /* Unrecognised or inappropriate gntref. */
404: #define GNTST_bad_handle (-4) /* Unrecognised or inappropriate handle. */
405: #define GNTST_bad_virt_addr (-5) /* Inappropriate virtual address to map. */
406: #define GNTST_bad_dev_addr (-6) /* Inappropriate device address to unmap.*/
407: #define GNTST_no_device_space (-7) /* Out of space in I/O MMU. */
408: #define GNTST_permission_denied (-8) /* Not enough privilege for operation. */
409: #define GNTST_bad_page (-9) /* Specified page was invalid for op. */
410: #define GNTST_bad_copy_arg (-10) /* copy arguments cross page boundary. */
411: #define GNTST_address_too_big (-11) /* transfer page address too large. */
412:
413: #define GNTTABOP_error_msgs { \
414: "okay", \
415: "undefined error", \
416: "unrecognised domain id", \
417: "invalid grant reference", \
418: "invalid mapping handle", \
419: "invalid virtual address", \
420: "invalid device address", \
421: "no spare translation slot in the I/O MMU", \
422: "permission denied", \
423: "bad page", \
424: "copy arguments cross page boundary", \
425: "page address size too large" \
426: }
427:
428: #endif /* __XEN_PUBLIC_GRANT_TABLE_H__ */
429:
430: /*
431: * Local variables:
432: * mode: C
433: * c-set-style: "BSD"
434: * c-basic-offset: 4
435: * tab-width: 4
436: * indent-tabs-mode: nil
437: * End:
438: */
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