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1/******************************************************************************
2 * blkif.h
1/******************************************************************************
2 * blkif.h
3 *
3 *
4 * Unified block-device I/O interface for Xen guest OSes.
4 * Unified block-device I/O interface for Xen guest OSes.
5 *
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to
8 * deal in the Software without restriction, including without limitation the
9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 * DEALINGS IN THE SOFTWARE.
23 *
24 * Copyright (c) 2003-2004, Keir Fraser
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to
8 * deal in the Software without restriction, including without limitation the
9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 * DEALINGS IN THE SOFTWARE.
23 *
24 * Copyright (c) 2003-2004, Keir Fraser
25 * Copyright (c) 2012, Spectra Logic Corporation
25 */
26
27#ifndef __XEN_PUBLIC_IO_BLKIF_H__
28#define __XEN_PUBLIC_IO_BLKIF_H__
29
30#include <xen/interface/io/ring.h>
31#include <xen/interface/grant_table.h>
32
33/*
34 * Front->back notifications: When enqueuing a new request, sending a
35 * notification can be made conditional on req_event (i.e., the generic
36 * hold-off mechanism provided by the ring macros). Backends must set
37 * req_event appropriately (e.g., using RING_FINAL_CHECK_FOR_REQUESTS()).
26 */
27
28#ifndef __XEN_PUBLIC_IO_BLKIF_H__
29#define __XEN_PUBLIC_IO_BLKIF_H__
30
31#include <xen/interface/io/ring.h>
32#include <xen/interface/grant_table.h>
33
34/*
35 * Front->back notifications: When enqueuing a new request, sending a
36 * notification can be made conditional on req_event (i.e., the generic
37 * hold-off mechanism provided by the ring macros). Backends must set
38 * req_event appropriately (e.g., using RING_FINAL_CHECK_FOR_REQUESTS()).
38 *
39 *
39 * Back->front notifications: When enqueuing a new response, sending a
40 * notification can be made conditional on rsp_event (i.e., the generic
41 * hold-off mechanism provided by the ring macros). Frontends must set
42 * rsp_event appropriately (e.g., using RING_FINAL_CHECK_FOR_RESPONSES()).
43 */
44
45#ifndef blkif_vdev_t
46#define blkif_vdev_t uint16_t
47#endif
48#define blkif_sector_t uint64_t
49
50/*
40 * Back->front notifications: When enqueuing a new response, sending a
41 * notification can be made conditional on rsp_event (i.e., the generic
42 * hold-off mechanism provided by the ring macros). Frontends must set
43 * rsp_event appropriately (e.g., using RING_FINAL_CHECK_FOR_RESPONSES()).
44 */
45
46#ifndef blkif_vdev_t
47#define blkif_vdev_t uint16_t
48#endif
49#define blkif_sector_t uint64_t
50
51/*
52 * Feature and Parameter Negotiation
53 * =================================
54 * The two halves of a Xen block driver utilize nodes within the XenStore to
55 * communicate capabilities and to negotiate operating parameters. This
56 * section enumerates these nodes which reside in the respective front and
57 * backend portions of the XenStore, following the XenBus convention.
58 *
59 * All data in the XenStore is stored as strings. Nodes specifying numeric
60 * values are encoded in decimal. Integer value ranges listed below are
61 * expressed as fixed sized integer types capable of storing the conversion
62 * of a properly formated node string, without loss of information.
63 *
64 * Any specified default value is in effect if the corresponding XenBus node
65 * is not present in the XenStore.
66 *
67 * XenStore nodes in sections marked "PRIVATE" are solely for use by the
68 * driver side whose XenBus tree contains them.
69 *
70 * See the XenBus state transition diagram below for details on when XenBus
71 * nodes must be published and when they can be queried.
72 *
73 *****************************************************************************
74 * Backend XenBus Nodes
75 *****************************************************************************
76 *
77 *------------------ Backend Device Identification (PRIVATE) ------------------
78 *
79 * mode
80 * Values: "r" (read only), "w" (writable)
81 *
82 * The read or write access permissions to the backing store to be
83 * granted to the frontend.
84 *
85 * params
86 * Values: string
87 *
88 * A free formatted string providing sufficient information for the
89 * backend driver to open the backing device. (e.g. the path to the
90 * file or block device representing the backing store.)
91 *
92 * type
93 * Values: "file", "phy", "tap"
94 *
95 * The type of the backing device/object.
96 *
97 *--------------------------------- Features ---------------------------------
98 *
99 * feature-barrier
100 * Values: 0/1 (boolean)
101 * Default Value: 0
102 *
103 * A value of "1" indicates that the backend can process requests
104 * containing the BLKIF_OP_WRITE_BARRIER request opcode. Requests
105 * of this type may still be returned at any time with the
106 * BLKIF_RSP_EOPNOTSUPP result code.
107 *
108 * feature-flush-cache
109 * Values: 0/1 (boolean)
110 * Default Value: 0
111 *
112 * A value of "1" indicates that the backend can process requests
113 * containing the BLKIF_OP_FLUSH_DISKCACHE request opcode. Requests
114 * of this type may still be returned at any time with the
115 * BLKIF_RSP_EOPNOTSUPP result code.
116 *
117 * feature-discard
118 * Values: 0/1 (boolean)
119 * Default Value: 0
120 *
121 * A value of "1" indicates that the backend can process requests
122 * containing the BLKIF_OP_DISCARD request opcode. Requests
123 * of this type may still be returned at any time with the
124 * BLKIF_RSP_EOPNOTSUPP result code.
125 *
126 *----------------------- Request Transport Parameters ------------------------
127 *
128 * max-ring-page-order
129 * Values: <uint32_t>
130 * Default Value: 0
131 * Notes: 1, 3
132 *
133 * The maximum supported size of the request ring buffer in units of
134 * lb(machine pages). (e.g. 0 == 1 page, 1 = 2 pages, 2 == 4 pages,
135 * etc.).
136 *
137 * max-ring-pages
138 * Values: <uint32_t>
139 * Default Value: 1
140 * Notes: 2, 3
141 *
142 * The maximum supported size of the request ring buffer in units of
143 * machine pages. The value must be a power of 2.
144 *
145 * max-requests <uint32_t>
146 * Default Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE)
147 * Maximum Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE * max-ring-pages)
148 *
149 * The maximum number of concurrent, logical requests that will be
150 * issued by the backend.
151 *
152 * Note: A logical request may span multiple ring entries.
153 *
154 * max-request-segments
155 * Values: <uint8_t>
156 * Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK
157 * Maximum Value: BLKIF_MAX_SEGMENTS_PER_REQUEST
158 *
159 * The maximum value of blkif_request.nr_segments supported by
160 * the backend.
161 *
162 * max-request-size
163 * Values: <uint32_t>
164 * Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK * PAGE_SIZE
165 * Maximum Value: BLKIF_MAX_SEGMENTS_PER_REQUEST * PAGE_SIZE
166 *
167 * The maximum amount of data, in bytes, that can be referenced by a
168 * request type that accesses frontend memory (currently BLKIF_OP_READ,
169 * BLKIF_OP_WRITE, or BLKIF_OP_WRITE_BARRIER).
170 *
171 *------------------------- Backend Device Properties -------------------------
172 *
173 * discard-aligment
174 * Values: <uint32_t>
175 * Default Value: 0
176 * Notes: 4, 5
177 *
178 * The offset, in bytes from the beginning of the virtual block device,
179 * to the first, addressable, discard extent on the underlying device.
180 *
181 * discard-granularity
182 * Values: <uint32_t>
183 * Default Value: <"sector-size">
184 * Notes: 4
185 *
186 * The size, in bytes, of the individually addressable discard extents
187 * of the underlying device.
188 *
189 * discard-secure
190 * Values: 0/1 (boolean)
191 * Default Value: 0
192 *
193 * A value of "1" indicates that the backend can process BLKIF_OP_DISCARD
194 * requests with the BLKIF_DISCARD_SECURE flag set.
195 *
196 * info
197 * Values: <uint32_t> (bitmap)
198 *
199 * A collection of bit flags describing attributes of the backing
200 * device. The VDISK_* macros define the meaning of each bit
201 * location.
202 *
203 * sector-size
204 * Values: <uint32_t>
205 *
206 * The native sector size, in bytes, of the backend device.
207 *
208 * sectors
209 * Values: <uint64_t>
210 *
211 * The size of the backend device, expressed in units of its native
212 * sector size ("sector-size").
213 *
214 *****************************************************************************
215 * Frontend XenBus Nodes
216 *****************************************************************************
217 *
218 *----------------------- Request Transport Parameters -----------------------
219 *
220 * event-channel
221 * Values: <uint32_t>
222 *
223 * The identifier of the Xen event channel used to signal activity
224 * in the ring buffer.
225 *
226 * ring-ref
227 * Values: <uint32_t>
228 * Notes: 6
229 *
230 * The Xen grant reference granting permission for the backend to map
231 * the sole page in a single page sized ring buffer.
232 *
233 * ring-ref%u
234 * Values: <uint32_t>
235 * Notes: 6
236 *
237 * For a frontend providing a multi-page ring, a "num-ring-pages" sized
238 * list of nodes, each containing a Xen grant reference granting
239 * permission for the backend to map the page of the ring located
240 * at page index "%u". Page indexes are zero based.
241 *
242 * protocol
243 * Values: string (XEN_IO_PROTO_ABI_*)
244 * Default Value: XEN_IO_PROTO_ABI_NATIVE
245 *
246 * The machine ABI rules governing the format of all ring request and
247 * response structures.
248 *
249 * ring-page-order
250 * Values: <uint32_t>
251 * Default Value: 0
252 * Maximum Value: MAX(ffs(max-ring-pages) - 1, max-ring-page-order)
253 * Notes: 1, 3
254 *
255 * The size of the frontend allocated request ring buffer in units
256 * of lb(machine pages). (e.g. 0 == 1 page, 1 = 2 pages, 2 == 4 pages,
257 * etc.).
258 *
259 * num-ring-pages
260 * Values: <uint32_t>
261 * Default Value: 1
262 * Maximum Value: MAX(max-ring-pages,(0x1 << max-ring-page-order))
263 * Notes: 2, 3
264 *
265 * The size of the frontend allocated request ring buffer in units of
266 * machine pages. The value must be a power of 2.
267 *
268 * max-requests
269 * Values: <uint32_t>
270 * Default Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE)
271 * Maximum Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE * max-ring_pages)
272 *
273 * The maximum number of concurrent, logical requests that will be
274 * issued by the frontend.
275 *
276 * Note: A logical request may span multiple ring entries.
277 *
278 * max-request-segments
279 * Values: <uint8_t>
280 * Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK
281 * Maximum Value: MIN(255, backend/max-request-segments)
282 *
283 * The maximum value the frontend will set in the
284 * blkif_request.nr_segments field.
285 *
286 * max-request-size
287 * Values: <uint32_t>
288 * Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK * PAGE_SIZE
289 * Maximum Value: max-request-segments * PAGE_SIZE
290 *
291 * The maximum amount of data, in bytes, that can be referenced by
292 * a request type that accesses frontend memory (currently BLKIF_OP_READ,
293 * BLKIF_OP_WRITE, or BLKIF_OP_WRITE_BARRIER).
294 *
295 *------------------------- Virtual Device Properties -------------------------
296 *
297 * device-type
298 * Values: "disk", "cdrom", "floppy", etc.
299 *
300 * virtual-device
301 * Values: <uint32_t>
302 *
303 * A value indicating the physical device to virtualize within the
304 * frontend's domain. (e.g. "The first ATA disk", "The third SCSI
305 * disk", etc.)
306 *
307 * See docs/misc/vbd-interface.txt for details on the format of this
308 * value.
309 *
310 * Notes
311 * -----
312 * (1) Multi-page ring buffer scheme first developed in the Citrix XenServer
313 * PV drivers.
314 * (2) Multi-page ring buffer scheme first used in some RedHat distributions
315 * including a distribution deployed on certain nodes of the Amazon
316 * EC2 cluster.
317 * (3) Support for multi-page ring buffers was implemented independently,
318 * in slightly different forms, by both Citrix and RedHat/Amazon.
319 * For full interoperability, block front and backends should publish
320 * identical ring parameters, adjusted for unit differences, to the
321 * XenStore nodes used in both schemes.
322 * (4) Devices that support discard functionality may internally allocate
323 * space (discardable extents) in units that are larger than the
324 * exported logical block size.
325 * (5) The discard-alignment parameter allows a physical device to be
326 * partitioned into virtual devices that do not necessarily begin or
327 * end on a discardable extent boundary.
328 * (6) When there is only a single page allocated to the request ring,
329 * 'ring-ref' is used to communicate the grant reference for this
330 * page to the backend. When using a multi-page ring, the 'ring-ref'
331 * node is not created. Instead 'ring-ref0' - 'ring-refN' are used.
332 */
333
334/*
335 * STATE DIAGRAMS
336 *
337 *****************************************************************************
338 * Startup *
339 *****************************************************************************
340 *
341 * Tool stack creates front and back nodes with state XenbusStateInitialising.
342 *
343 * Front Back
344 * ================================= =====================================
345 * XenbusStateInitialising XenbusStateInitialising
346 * o Query virtual device o Query backend device identification
347 * properties. data.
348 * o Setup OS device instance. o Open and validate backend device.
349 * o Publish backend features and
350 * transport parameters.
351 * |
352 * |
353 * V
354 * XenbusStateInitWait
355 *
356 * o Query backend features and
357 * transport parameters.
358 * o Allocate and initialize the
359 * request ring.
360 * o Publish transport parameters
361 * that will be in effect during
362 * this connection.
363 * |
364 * |
365 * V
366 * XenbusStateInitialised
367 *
368 * o Query frontend transport parameters.
369 * o Connect to the request ring and
370 * event channel.
371 * o Publish backend device properties.
372 * |
373 * |
374 * V
375 * XenbusStateConnected
376 *
377 * o Query backend device properties.
378 * o Finalize OS virtual device
379 * instance.
380 * |
381 * |
382 * V
383 * XenbusStateConnected
384 *
385 * Note: Drivers that do not support any optional features, or the negotiation
386 * of transport parameters, can skip certain states in the state machine:
387 *
388 * o A frontend may transition to XenbusStateInitialised without
389 * waiting for the backend to enter XenbusStateInitWait. In this
390 * case, default transport parameters are in effect and any
391 * transport parameters published by the frontend must contain
392 * their default values.
393 *
394 * o A backend may transition to XenbusStateInitialised, bypassing
395 * XenbusStateInitWait, without waiting for the frontend to first
396 * enter the XenbusStateInitialised state. In this case, default
397 * transport parameters are in effect and any transport parameters
398 * published by the backend must contain their default values.
399 *
400 * Drivers that support optional features and/or transport parameter
401 * negotiation must tolerate these additional state transition paths.
402 * In general this means performing the work of any skipped state
403 * transition, if it has not already been performed, in addition to the
404 * work associated with entry into the current state.
405 */
406
407/*
51 * REQUEST CODES.
52 */
53#define BLKIF_OP_READ 0
54#define BLKIF_OP_WRITE 1
55/*
408 * REQUEST CODES.
409 */
410#define BLKIF_OP_READ 0
411#define BLKIF_OP_WRITE 1
412/*
56 * Recognised only if "feature-barrier" is present in backend xenbus info.
57 * The "feature-barrier" node contains a boolean indicating whether barrier
58 * requests are likely to succeed or fail. Either way, a barrier request
59 * may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by
60 * the underlying block-device hardware. The boolean simply indicates whether
61 * or not it is worthwhile for the frontend to attempt barrier requests.
62 * If a backend does not recognise BLKIF_OP_WRITE_BARRIER, it should *not*
63 * create the "feature-barrier" node!
413 * All writes issued prior to a request with the BLKIF_OP_WRITE_BARRIER
414 * operation code ("barrier request") must be completed prior to the
415 * execution of the barrier request. All writes issued after the barrier
416 * request must not execute until after the completion of the barrier request.
417 *
418 * Optional. See "feature-barrier" XenBus node documentation above.
64 */
65#define BLKIF_OP_WRITE_BARRIER 2
66/*
419 */
420#define BLKIF_OP_WRITE_BARRIER 2
421/*
67 * Recognised if "feature-flush-cache" is present in backend xenbus
68 * info. A flush will ask the underlying storage hardware to flush its
69 * non-volatile caches as appropriate. The "feature-flush-cache" node
70 * contains a boolean indicating whether flush requests are likely to
71 * succeed or fail. Either way, a flush request may fail at any time
72 * with BLKIF_RSP_EOPNOTSUPP if it is unsupported by the underlying
73 * block-device hardware. The boolean simply indicates whether or not it
74 * is worthwhile for the frontend to attempt flushes. If a backend does
75 * not recognise BLKIF_OP_WRITE_FLUSH_CACHE, it should *not* create the
76 * "feature-flush-cache" node!
422 * Commit any uncommitted contents of the backing device's volatile cache
423 * to stable storage.
424 *
425 * Optional. See "feature-flush-cache" XenBus node documentation above.
77 */
78#define BLKIF_OP_FLUSH_DISKCACHE 3
426 */
427#define BLKIF_OP_FLUSH_DISKCACHE 3
428/*
429 * Used in SLES sources for device specific command packet
430 * contained within the request. Reserved for that purpose.
431 */
432#define BLKIF_OP_RESERVED_1 4
433/*
434 * Indicate to the backend device that a region of storage is no longer in
435 * use, and may be discarded at any time without impact to the client. If
436 * the BLKIF_DISCARD_SECURE flag is set on the request, all copies of the
437 * discarded region on the device must be rendered unrecoverable before the
438 * command returns.
439 *
440 * This operation is analogous to performing a trim (ATA) or unamp (SCSI),
441 * command on a native device.
442 *
443 * More information about trim/unmap operations can be found at:
444 * http://t13.org/Documents/UploadedDocuments/docs2008/
445 * e07154r6-Data_Set_Management_Proposal_for_ATA-ACS2.doc
446 * http://www.seagate.com/staticfiles/support/disc/manuals/
447 * Interface%20manuals/100293068c.pdf
448 *
449 * Optional. See "feature-discard", "discard-alignment",
450 * "discard-granularity", and "discard-secure" in the XenBus node
451 * documentation above.
452 */
453#define BLKIF_OP_DISCARD 5
79
80/*
81 * Maximum scatter/gather segments associated with a request header block.
454
455/*
456 * Maximum scatter/gather segments associated with a request header block.
457 * This is carefully chosen so that sizeof(blkif_ring_t) <= PAGE_SIZE.
458 * NB. This could be 12 if the ring indexes weren't stored in the same page.
82 */
83#define BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK 11
84
85/*
86 * Maximum scatter/gather segments associated with a segment block.
87 */
88#define BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK 14
89
90/*
91 * Maximum scatter/gather segments per request (header + segment blocks).
92 */
93#define BLKIF_MAX_SEGMENTS_PER_REQUEST 255
94
459 */
460#define BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK 11
461
462/*
463 * Maximum scatter/gather segments associated with a segment block.
464 */
465#define BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK 14
466
467/*
468 * Maximum scatter/gather segments per request (header + segment blocks).
469 */
470#define BLKIF_MAX_SEGMENTS_PER_REQUEST 255
471
472/*
473 * NB. first_sect and last_sect in blkif_request_segment, as well as
474 * sector_number in blkif_request, are always expressed in 512-byte units.
475 * However they must be properly aligned to the real sector size of the
476 * physical disk, which is reported in the "sector-size" node in the backend
477 * xenbus info. Also the xenbus "sectors" node is expressed in 512-byte units.
478 */
95struct blkif_request_segment {
96 grant_ref_t gref; /* reference to I/O buffer frame */
97 /* @first_sect: first sector in frame to transfer (inclusive). */
98 /* @last_sect: last sector in frame to transfer (inclusive). */
99 uint8_t first_sect, last_sect;
100};
101typedef struct blkif_request_segment blkif_request_segment_t;
102
479struct blkif_request_segment {
480 grant_ref_t gref; /* reference to I/O buffer frame */
481 /* @first_sect: first sector in frame to transfer (inclusive). */
482 /* @last_sect: last sector in frame to transfer (inclusive). */
483 uint8_t first_sect, last_sect;
484};
485typedef struct blkif_request_segment blkif_request_segment_t;
486
487/*
488 * Starting ring element for any I/O request.
489 *
490 * One or more segment blocks can be inserted into the request ring
491 * just after a blkif_request_t, allowing requests to operate on
492 * up to BLKIF_MAX_SEGMENTS_PER_REQUEST.
493 *
494 * BLKIF_SEGS_TO_BLOCKS() can be used on blkif_requst.nr_segments
495 * to determine the number of contiguous ring entries associated
496 * with this request.
497 *
498 * Note: Due to the way Xen request rings operate, the producer and
499 * consumer indices of the ring must be incremented by the
500 * BLKIF_SEGS_TO_BLOCKS() value of the associated request.
501 * (e.g. a response to a 3 ring entry request must also consume
502 * 3 entries in the ring, even though only the first ring entry
503 * in the response has any data.)
504 */
103struct blkif_request {
104 uint8_t operation; /* BLKIF_OP_??? */
105 uint8_t nr_segments; /* number of segments */
106 blkif_vdev_t handle; /* only for read/write requests */
107 uint64_t id; /* private guest value, echoed in resp */
108 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
505struct blkif_request {
506 uint8_t operation; /* BLKIF_OP_??? */
507 uint8_t nr_segments; /* number of segments */
508 blkif_vdev_t handle; /* only for read/write requests */
509 uint64_t id; /* private guest value, echoed in resp */
510 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
109 struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK];
511 blkif_request_segment_t seg[BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK];
110};
111typedef struct blkif_request blkif_request_t;
112
512};
513typedef struct blkif_request blkif_request_t;
514
515/*
516 * A segment block is a ring request structure that contains only
517 * segment data.
518 *
519 * sizeof(struct blkif_segment_block) <= sizeof(struct blkif_request)
520 */
521struct blkif_segment_block {
522 blkif_request_segment_t seg[BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK];
523};
524typedef struct blkif_segment_block blkif_segment_block_t;
525
526/*
527 * Cast to this structure when blkif_request.operation == BLKIF_OP_DISCARD
528 * sizeof(struct blkif_request_discard) <= sizeof(struct blkif_request)
529 */
530struct blkif_request_discard {
531 uint8_t operation; /* BLKIF_OP_DISCARD */
532 uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */
533#define BLKIF_DISCARD_SECURE (1<<0) /* ignored if discard-secure=0 */
534 blkif_vdev_t handle; /* same as for read/write requests */
535 uint64_t id; /* private guest value, echoed in resp */
536 blkif_sector_t sector_number;/* start sector idx on disk */
537 uint64_t nr_sectors; /* number of contiguous sectors to discard*/
538};
539typedef struct blkif_request_discard blkif_request_discard_t;
540
113struct blkif_response {
114 uint64_t id; /* copied from request */
115 uint8_t operation; /* copied from request */
116 int16_t status; /* BLKIF_RSP_??? */
117};
118typedef struct blkif_response blkif_response_t;
119
120/*

--- 4 unchanged lines hidden (view full) ---

125 /* Operation failed for some unspecified reason (-EIO). */
126#define BLKIF_RSP_ERROR -1
127 /* Operation completed successfully. */
128#define BLKIF_RSP_OKAY 0
129
130/*
131 * Generate blkif ring structures and types.
132 */
541struct blkif_response {
542 uint64_t id; /* copied from request */
543 uint8_t operation; /* copied from request */
544 int16_t status; /* BLKIF_RSP_??? */
545};
546typedef struct blkif_response blkif_response_t;
547
548/*

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553 /* Operation failed for some unspecified reason (-EIO). */
554#define BLKIF_RSP_ERROR -1
555 /* Operation completed successfully. */
556#define BLKIF_RSP_OKAY 0
557
558/*
559 * Generate blkif ring structures and types.
560 */
133
134DEFINE_RING_TYPES(blkif, struct blkif_request, struct blkif_response);
135
561DEFINE_RING_TYPES(blkif, struct blkif_request, struct blkif_response);
562
136#define BLKRING_GET_SG_REQUEST(_r, _idx) \
137 ((struct blkif_request_segment *)RING_GET_REQUEST(_r, _idx))
563/*
564 * Index to, and treat as a segment block, an entry in the ring.
565 */
566#define BLKRING_GET_SEG_BLOCK(_r, _idx) \
567 (((blkif_segment_block_t *)RING_GET_REQUEST(_r, _idx))->seg)
138
568
139#define VDISK_CDROM 0x1
140#define VDISK_REMOVABLE 0x2
141#define VDISK_READONLY 0x4
142
143/*
144 * The number of ring request blocks required to handle an I/O
145 * request containing _segs segments.
146 */
569/*
570 * The number of ring request blocks required to handle an I/O
571 * request containing _segs segments.
572 */
147#define BLKIF_SEGS_TO_BLOCKS(_segs) \
148 ((((_segs - BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK) \
149 + (BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK - 1)) \
150 / BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK) + /*header_block*/1)
573#define BLKIF_SEGS_TO_BLOCKS(_segs) \
574 ((((_segs - BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK) \
575 + (BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK - 1)) \
576 / BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK) + /*header_block*/1)
151
577
578#define VDISK_CDROM 0x1
579#define VDISK_REMOVABLE 0x2
580#define VDISK_READONLY 0x4
581
152#endif /* __XEN_PUBLIC_IO_BLKIF_H__ */
153
154/*
155 * Local variables:
156 * mode: C
157 * c-set-style: "BSD"
158 * c-basic-offset: 4
159 * tab-width: 4
160 * indent-tabs-mode: nil
161 * End:
162 */
582#endif /* __XEN_PUBLIC_IO_BLKIF_H__ */
583
584/*
585 * Local variables:
586 * mode: C
587 * c-set-style: "BSD"
588 * c-basic-offset: 4
589 * tab-width: 4
590 * indent-tabs-mode: nil
591 * End:
592 */