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MAINTAINERS: add myself as a Xen maintainer
[qemu.git] / hw / block / xen_disk.c
blob477dfcca9ff4dc4dc79b23894edb32129e0f39d2
1 /*
2 * xen paravirt block device backend
3 *
4 * (c) Gerd Hoffmann <kraxel@redhat.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; under version 2 of the License.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, see <http://www.gnu.org/licenses/>.
17 *
18 * Contributions after 2012-01-13 are licensed under the terms of the
19 * GNU GPL, version 2 or (at your option) any later version.
20 */
21
22 #include "qemu/osdep.h"
23 #include "qemu/units.h"
24 #include <sys/ioctl.h>
25 #include <sys/uio.h>
26
27 #include "hw/hw.h"
28 #include "hw/xen/xen-legacy-backend.h"
29 #include "xen_blkif.h"
30 #include "sysemu/blockdev.h"
31 #include "sysemu/iothread.h"
32 #include "sysemu/block-backend.h"
33 #include "qapi/error.h"
34 #include "qapi/qmp/qdict.h"
35 #include "qapi/qmp/qstring.h"
36 #include "trace.h"
37
38 /* ------------------------------------------------------------- */
39
40 #define BLOCK_SIZE 512
41 #define IOCB_COUNT (BLKIF_MAX_SEGMENTS_PER_REQUEST + 2)
42
43 struct ioreq {
44 blkif_request_t req;
45 int16_t status;
46
47 /* parsed request */
48 off_t start;
49 QEMUIOVector v;
50 void *buf;
51 size_t size;
52 int presync;
53
54 /* aio status */
55 int aio_inflight;
56 int aio_errors;
57
58 struct XenBlkDev *blkdev;
59 QLIST_ENTRY(ioreq) list;
60 BlockAcctCookie acct;
61 };
62
63 #define MAX_RING_PAGE_ORDER 4
64
65 struct XenBlkDev {
66 struct XenLegacyDevice xendev; /* must be first */
67 char *params;
68 char *mode;
69 char *type;
70 char *dev;
71 char *devtype;
72 bool directiosafe;
73 const char *fileproto;
74 const char *filename;
75 unsigned int ring_ref[1 << MAX_RING_PAGE_ORDER];
76 unsigned int nr_ring_ref;
77 void *sring;
78 int64_t file_blk;
79 int64_t file_size;
80 int protocol;
81 blkif_back_rings_t rings;
82 int more_work;
83
84 /* request lists */
85 QLIST_HEAD(, ioreq) inflight;
86 QLIST_HEAD(, ioreq) finished;
87 QLIST_HEAD(, ioreq) freelist;
88 int requests_total;
89 int requests_inflight;
90 int requests_finished;
91 unsigned int max_requests;
92
93 gboolean feature_discard;
94
95 /* qemu block driver */
96 DriveInfo *dinfo;
97 BlockBackend *blk;
98 QEMUBH *bh;
99
100 IOThread *iothread;
101 AioContext *ctx;
102 };
103
104 /* ------------------------------------------------------------- */
105
106 static void ioreq_reset(struct ioreq *ioreq)
107 {
108 memset(&ioreq->req, 0, sizeof(ioreq->req));
109 ioreq->status = 0;
110 ioreq->start = 0;
111 ioreq->buf = NULL;
112 ioreq->size = 0;
113 ioreq->presync = 0;
114
115 ioreq->aio_inflight = 0;
116 ioreq->aio_errors = 0;
117
118 ioreq->blkdev = NULL;
119 memset(&ioreq->list, 0, sizeof(ioreq->list));
120 memset(&ioreq->acct, 0, sizeof(ioreq->acct));
121
122 qemu_iovec_reset(&ioreq->v);
123 }
124
125 static struct ioreq *ioreq_start(struct XenBlkDev *blkdev)
126 {
127 struct ioreq *ioreq = NULL;
128
129 if (QLIST_EMPTY(&blkdev->freelist)) {
130 if (blkdev->requests_total >= blkdev->max_requests) {
131 goto out;
132 }
133 /* allocate new struct */
134 ioreq = g_malloc0(sizeof(*ioreq));
135 ioreq->blkdev = blkdev;
136 blkdev->requests_total++;
137 qemu_iovec_init(&ioreq->v, 1);
138 } else {
139 /* get one from freelist */
140 ioreq = QLIST_FIRST(&blkdev->freelist);
141 QLIST_REMOVE(ioreq, list);
142 }
143 QLIST_INSERT_HEAD(&blkdev->inflight, ioreq, list);
144 blkdev->requests_inflight++;
145
146 out:
147 return ioreq;
148 }
149
150 static void ioreq_finish(struct ioreq *ioreq)
151 {
152 struct XenBlkDev *blkdev = ioreq->blkdev;
153
154 QLIST_REMOVE(ioreq, list);
155 QLIST_INSERT_HEAD(&blkdev->finished, ioreq, list);
156 blkdev->requests_inflight--;
157 blkdev->requests_finished++;
158 }
159
160 static void ioreq_release(struct ioreq *ioreq, bool finish)
161 {
162 struct XenBlkDev *blkdev = ioreq->blkdev;
163
164 QLIST_REMOVE(ioreq, list);
165 ioreq_reset(ioreq);
166 ioreq->blkdev = blkdev;
167 QLIST_INSERT_HEAD(&blkdev->freelist, ioreq, list);
168 if (finish) {
169 blkdev->requests_finished--;
170 } else {
171 blkdev->requests_inflight--;
172 }
173 }
174
175 /*
176 * translate request into iovec + start offset
177 * do sanity checks along the way
178 */
179 static int ioreq_parse(struct ioreq *ioreq)
180 {
181 struct XenBlkDev *blkdev = ioreq->blkdev;
182 struct XenLegacyDevice *xendev = &blkdev->xendev;
183 size_t len;
184 int i;
185
186 xen_pv_printf(xendev, 3,
187 "op %d, nr %d, handle %d, id %" PRId64 ", sector %" PRId64 "\n",
188 ioreq->req.operation, ioreq->req.nr_segments,
189 ioreq->req.handle, ioreq->req.id, ioreq->req.sector_number);
190 switch (ioreq->req.operation) {
191 case BLKIF_OP_READ:
192 break;
193 case BLKIF_OP_FLUSH_DISKCACHE:
194 ioreq->presync = 1;
195 if (!ioreq->req.nr_segments) {
196 return 0;
197 }
198 /* fall through */
199 case BLKIF_OP_WRITE:
200 break;
201 case BLKIF_OP_DISCARD:
202 return 0;
203 default:
204 xen_pv_printf(xendev, 0, "error: unknown operation (%d)\n",
205 ioreq->req.operation);
206 goto err;
207 };
208
209 if (ioreq->req.operation != BLKIF_OP_READ && blkdev->mode[0] != 'w') {
210 xen_pv_printf(xendev, 0, "error: write req for ro device\n");
211 goto err;
212 }
213
214 ioreq->start = ioreq->req.sector_number * blkdev->file_blk;
215 for (i = 0; i < ioreq->req.nr_segments; i++) {
216 if (i == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
217 xen_pv_printf(xendev, 0, "error: nr_segments too big\n");
218 goto err;
219 }
220 if (ioreq->req.seg[i].first_sect > ioreq->req.seg[i].last_sect) {
221 xen_pv_printf(xendev, 0, "error: first > last sector\n");
222 goto err;
223 }
224 if (ioreq->req.seg[i].last_sect * BLOCK_SIZE >= XC_PAGE_SIZE) {
225 xen_pv_printf(xendev, 0, "error: page crossing\n");
226 goto err;
227 }
228
229 len = (ioreq->req.seg[i].last_sect - ioreq->req.seg[i].first_sect + 1) * blkdev->file_blk;
230 ioreq->size += len;
231 }
232 if (ioreq->start + ioreq->size > blkdev->file_size) {
233 xen_pv_printf(xendev, 0, "error: access beyond end of file\n");
234 goto err;
235 }
236 return 0;
237
238 err:
239 ioreq->status = BLKIF_RSP_ERROR;
240 return -1;
241 }
242
243 static int ioreq_grant_copy(struct ioreq *ioreq)
244 {
245 struct XenBlkDev *blkdev = ioreq->blkdev;
246 struct XenLegacyDevice *xendev = &blkdev->xendev;
247 XenGrantCopySegment segs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
248 int i, count, rc;
249 int64_t file_blk = blkdev->file_blk;
250 bool to_domain = (ioreq->req.operation == BLKIF_OP_READ);
251 void *virt = ioreq->buf;
252
253 if (ioreq->req.nr_segments == 0) {
254 return 0;
255 }
256
257 count = ioreq->req.nr_segments;
258
259 for (i = 0; i < count; i++) {
260 if (to_domain) {
261 segs[i].dest.foreign.ref = ioreq->req.seg[i].gref;
262 segs[i].dest.foreign.offset = ioreq->req.seg[i].first_sect * file_blk;
263 segs[i].source.virt = virt;
264 } else {
265 segs[i].source.foreign.ref = ioreq->req.seg[i].gref;
266 segs[i].source.foreign.offset = ioreq->req.seg[i].first_sect * file_blk;
267 segs[i].dest.virt = virt;
268 }
269 segs[i].len = (ioreq->req.seg[i].last_sect
270 - ioreq->req.seg[i].first_sect + 1) * file_blk;
271 virt += segs[i].len;
272 }
273
274 rc = xen_be_copy_grant_refs(xendev, to_domain, segs, count);
275
276 if (rc) {
277 xen_pv_printf(xendev, 0,
278 "failed to copy data %d\n", rc);
279 ioreq->aio_errors++;
280 return -1;
281 }
282
283 return rc;
284 }
285
286 static int ioreq_runio_qemu_aio(struct ioreq *ioreq);
287
288 static void qemu_aio_complete(void *opaque, int ret)
289 {
290 struct ioreq *ioreq = opaque;
291 struct XenBlkDev *blkdev = ioreq->blkdev;
292 struct XenLegacyDevice *xendev = &blkdev->xendev;
293
294 aio_context_acquire(blkdev->ctx);
295
296 if (ret != 0) {
297 xen_pv_printf(xendev, 0, "%s I/O error\n",
298 ioreq->req.operation == BLKIF_OP_READ ? "read" : "write");
299 ioreq->aio_errors++;
300 }
301
302 ioreq->aio_inflight--;
303 if (ioreq->presync) {
304 ioreq->presync = 0;
305 ioreq_runio_qemu_aio(ioreq);
306 goto done;
307 }
308 if (ioreq->aio_inflight > 0) {
309 goto done;
310 }
311
312 switch (ioreq->req.operation) {
313 case BLKIF_OP_READ:
314 /* in case of failure ioreq->aio_errors is increased */
315 if (ret == 0) {
316 ioreq_grant_copy(ioreq);
317 }
318 qemu_vfree(ioreq->buf);
319 break;
320 case BLKIF_OP_WRITE:
321 case BLKIF_OP_FLUSH_DISKCACHE:
322 if (!ioreq->req.nr_segments) {
323 break;
324 }
325 qemu_vfree(ioreq->buf);
326 break;
327 default:
328 break;
329 }
330
331 ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY;
332 ioreq_finish(ioreq);
333
334 switch (ioreq->req.operation) {
335 case BLKIF_OP_WRITE:
336 case BLKIF_OP_FLUSH_DISKCACHE:
337 if (!ioreq->req.nr_segments) {
338 break;
339 }
340 case BLKIF_OP_READ:
341 if (ioreq->status == BLKIF_RSP_OKAY) {
342 block_acct_done(blk_get_stats(blkdev->blk), &ioreq->acct);
343 } else {
344 block_acct_failed(blk_get_stats(blkdev->blk), &ioreq->acct);
345 }
346 break;
347 case BLKIF_OP_DISCARD:
348 default:
349 break;
350 }
351 qemu_bh_schedule(blkdev->bh);
352
353 done:
354 aio_context_release(blkdev->ctx);
355 }
356
357 static bool blk_split_discard(struct ioreq *ioreq, blkif_sector_t sector_number,
358 uint64_t nr_sectors)
359 {
360 struct XenBlkDev *blkdev = ioreq->blkdev;
361 int64_t byte_offset;
362 int byte_chunk;
363 uint64_t byte_remaining, limit;
364 uint64_t sec_start = sector_number;
365 uint64_t sec_count = nr_sectors;
366
367 /* Wrap around, or overflowing byte limit? */
368 if (sec_start + sec_count < sec_count ||
369 sec_start + sec_count > INT64_MAX >> BDRV_SECTOR_BITS) {
370 return false;
371 }
372
373 limit = BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS;
374 byte_offset = sec_start << BDRV_SECTOR_BITS;
375 byte_remaining = sec_count << BDRV_SECTOR_BITS;
376
377 do {
378 byte_chunk = byte_remaining > limit ? limit : byte_remaining;
379 ioreq->aio_inflight++;
380 blk_aio_pdiscard(blkdev->blk, byte_offset, byte_chunk,
381 qemu_aio_complete, ioreq);
382 byte_remaining -= byte_chunk;
383 byte_offset += byte_chunk;
384 } while (byte_remaining > 0);
385
386 return true;
387 }
388
389 static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
390 {
391 struct XenBlkDev *blkdev = ioreq->blkdev;
392
393 ioreq->buf = qemu_memalign(XC_PAGE_SIZE, ioreq->size);
394 if (ioreq->req.nr_segments &&
395 (ioreq->req.operation == BLKIF_OP_WRITE ||
396 ioreq->req.operation == BLKIF_OP_FLUSH_DISKCACHE) &&
397 ioreq_grant_copy(ioreq)) {
398 qemu_vfree(ioreq->buf);
399 goto err;
400 }
401
402 ioreq->aio_inflight++;
403 if (ioreq->presync) {
404 blk_aio_flush(ioreq->blkdev->blk, qemu_aio_complete, ioreq);
405 return 0;
406 }
407
408 switch (ioreq->req.operation) {
409 case BLKIF_OP_READ:
410 qemu_iovec_add(&ioreq->v, ioreq->buf, ioreq->size);
411 block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct,
412 ioreq->v.size, BLOCK_ACCT_READ);
413 ioreq->aio_inflight++;
414 blk_aio_preadv(blkdev->blk, ioreq->start, &ioreq->v, 0,
415 qemu_aio_complete, ioreq);
416 break;
417 case BLKIF_OP_WRITE:
418 case BLKIF_OP_FLUSH_DISKCACHE:
419 if (!ioreq->req.nr_segments) {
420 break;
421 }
422
423 qemu_iovec_add(&ioreq->v, ioreq->buf, ioreq->size);
424 block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct,
425 ioreq->v.size,
426 ioreq->req.operation == BLKIF_OP_WRITE ?
427 BLOCK_ACCT_WRITE : BLOCK_ACCT_FLUSH);
428 ioreq->aio_inflight++;
429 blk_aio_pwritev(blkdev->blk, ioreq->start, &ioreq->v, 0,
430 qemu_aio_complete, ioreq);
431 break;
432 case BLKIF_OP_DISCARD:
433 {
434 struct blkif_request_discard *req = (void *)&ioreq->req;
435 if (!blk_split_discard(ioreq, req->sector_number, req->nr_sectors)) {
436 goto err;
437 }
438 break;
439 }
440 default:
441 /* unknown operation (shouldn't happen -- parse catches this) */
442 goto err;
443 }
444
445 qemu_aio_complete(ioreq, 0);
446
447 return 0;
448
449 err:
450 ioreq_finish(ioreq);
451 ioreq->status = BLKIF_RSP_ERROR;
452 return -1;
453 }
454
455 static int blk_send_response_one(struct ioreq *ioreq)
456 {
457 struct XenBlkDev *blkdev = ioreq->blkdev;
458 int send_notify = 0;
459 int have_requests = 0;
460 blkif_response_t *resp;
461
462 /* Place on the response ring for the relevant domain. */
463 switch (blkdev->protocol) {
464 case BLKIF_PROTOCOL_NATIVE:
465 resp = (blkif_response_t *) RING_GET_RESPONSE(&blkdev->rings.native,
466 blkdev->rings.native.rsp_prod_pvt);
467 break;
468 case BLKIF_PROTOCOL_X86_32:
469 resp = (blkif_response_t *) RING_GET_RESPONSE(&blkdev->rings.x86_32_part,
470 blkdev->rings.x86_32_part.rsp_prod_pvt);
471 break;
472 case BLKIF_PROTOCOL_X86_64:
473 resp = (blkif_response_t *) RING_GET_RESPONSE(&blkdev->rings.x86_64_part,
474 blkdev->rings.x86_64_part.rsp_prod_pvt);
475 break;
476 default:
477 return 0;
478 }
479
480 resp->id = ioreq->req.id;
481 resp->operation = ioreq->req.operation;
482 resp->status = ioreq->status;
483
484 blkdev->rings.common.rsp_prod_pvt++;
485
486 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blkdev->rings.common, send_notify);
487 if (blkdev->rings.common.rsp_prod_pvt == blkdev->rings.common.req_cons) {
488 /*
489 * Tail check for pending requests. Allows frontend to avoid
490 * notifications if requests are already in flight (lower
491 * overheads and promotes batching).
492 */
493 RING_FINAL_CHECK_FOR_REQUESTS(&blkdev->rings.common, have_requests);
494 } else if (RING_HAS_UNCONSUMED_REQUESTS(&blkdev->rings.common)) {
495 have_requests = 1;
496 }
497
498 if (have_requests) {
499 blkdev->more_work++;
500 }
501 return send_notify;
502 }
503
504 /* walk finished list, send outstanding responses, free requests */
505 static void blk_send_response_all(struct XenBlkDev *blkdev)
506 {
507 struct ioreq *ioreq;
508 int send_notify = 0;
509
510 while (!QLIST_EMPTY(&blkdev->finished)) {
511 ioreq = QLIST_FIRST(&blkdev->finished);
512 send_notify += blk_send_response_one(ioreq);
513 ioreq_release(ioreq, true);
514 }
515 if (send_notify) {
516 xen_pv_send_notify(&blkdev->xendev);
517 }
518 }
519
520 static int blk_get_request(struct XenBlkDev *blkdev, struct ioreq *ioreq, RING_IDX rc)
521 {
522 switch (blkdev->protocol) {
523 case BLKIF_PROTOCOL_NATIVE:
524 memcpy(&ioreq->req, RING_GET_REQUEST(&blkdev->rings.native, rc),
525 sizeof(ioreq->req));
526 break;
527 case BLKIF_PROTOCOL_X86_32:
528 blkif_get_x86_32_req(&ioreq->req,
529 RING_GET_REQUEST(&blkdev->rings.x86_32_part, rc));
530 break;
531 case BLKIF_PROTOCOL_X86_64:
532 blkif_get_x86_64_req(&ioreq->req,
533 RING_GET_REQUEST(&blkdev->rings.x86_64_part, rc));
534 break;
535 }
536 /* Prevent the compiler from accessing the on-ring fields instead. */
537 barrier();
538 return 0;
539 }
540
541 static void blk_handle_requests(struct XenBlkDev *blkdev)
542 {
543 RING_IDX rc, rp;
544 struct ioreq *ioreq;
545
546 blkdev->more_work = 0;
547
548 rc = blkdev->rings.common.req_cons;
549 rp = blkdev->rings.common.sring->req_prod;
550 xen_rmb(); /* Ensure we see queued requests up to 'rp'. */
551
552 blk_send_response_all(blkdev);
553 while (rc != rp) {
554 /* pull request from ring */
555 if (RING_REQUEST_CONS_OVERFLOW(&blkdev->rings.common, rc)) {
556 break;
557 }
558 ioreq = ioreq_start(blkdev);
559 if (ioreq == NULL) {
560 blkdev->more_work++;
561 break;
562 }
563 blk_get_request(blkdev, ioreq, rc);
564 blkdev->rings.common.req_cons = ++rc;
565
566 /* parse them */
567 if (ioreq_parse(ioreq) != 0) {
568
569 switch (ioreq->req.operation) {
570 case BLKIF_OP_READ:
571 block_acct_invalid(blk_get_stats(blkdev->blk),
572 BLOCK_ACCT_READ);
573 break;
574 case BLKIF_OP_WRITE:
575 block_acct_invalid(blk_get_stats(blkdev->blk),
576 BLOCK_ACCT_WRITE);
577 break;
578 case BLKIF_OP_FLUSH_DISKCACHE:
579 block_acct_invalid(blk_get_stats(blkdev->blk),
580 BLOCK_ACCT_FLUSH);
581 default:
582 break;
583 };
584
585 if (blk_send_response_one(ioreq)) {
586 xen_pv_send_notify(&blkdev->xendev);
587 }
588 ioreq_release(ioreq, false);
589 continue;
590 }
591
592 ioreq_runio_qemu_aio(ioreq);
593 }
594
595 if (blkdev->more_work && blkdev->requests_inflight < blkdev->max_requests) {
596 qemu_bh_schedule(blkdev->bh);
597 }
598 }
599
600 /* ------------------------------------------------------------- */
601
602 static void blk_bh(void *opaque)
603 {
604 struct XenBlkDev *blkdev = opaque;
605
606 aio_context_acquire(blkdev->ctx);
607 blk_handle_requests(blkdev);
608 aio_context_release(blkdev->ctx);
609 }
610
611 static void blk_alloc(struct XenLegacyDevice *xendev)
612 {
613 struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
614 Error *err = NULL;
615
616 trace_xen_disk_alloc(xendev->name);
617
618 QLIST_INIT(&blkdev->inflight);
619 QLIST_INIT(&blkdev->finished);
620 QLIST_INIT(&blkdev->freelist);
621
622 blkdev->iothread = iothread_create(xendev->name, &err);
623 assert(!err);
624
625 blkdev->ctx = iothread_get_aio_context(blkdev->iothread);
626 blkdev->bh = aio_bh_new(blkdev->ctx, blk_bh, blkdev);
627 }
628
629 static void blk_parse_discard(struct XenBlkDev *blkdev)
630 {
631 struct XenLegacyDevice *xendev = &blkdev->xendev;
632 int enable;
633
634 blkdev->feature_discard = true;
635
636 if (xenstore_read_be_int(xendev, "discard-enable", &enable) == 0) {
637 blkdev->feature_discard = !!enable;
638 }
639
640 if (blkdev->feature_discard) {
641 xenstore_write_be_int(xendev, "feature-discard", 1);
642 }
643 }
644
645 static int blk_init(struct XenLegacyDevice *xendev)
646 {
647 struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
648 int info = 0;
649 char *directiosafe = NULL;
650
651 trace_xen_disk_init(xendev->name);
652
653 /* read xenstore entries */
654 if (blkdev->params == NULL) {
655 char *h = NULL;
656 blkdev->params = xenstore_read_be_str(xendev, "params");
657 if (blkdev->params != NULL) {
658 h = strchr(blkdev->params, ':');
659 }
660 if (h != NULL) {
661 blkdev->fileproto = blkdev->params;
662 blkdev->filename = h+1;
663 *h = 0;
664 } else {
665 blkdev->fileproto = "<unset>";
666 blkdev->filename = blkdev->params;
667 }
668 }
669 if (!strcmp("aio", blkdev->fileproto)) {
670 blkdev->fileproto = "raw";
671 }
672 if (!strcmp("vhd", blkdev->fileproto)) {
673 blkdev->fileproto = "vpc";
674 }
675 if (blkdev->mode == NULL) {
676 blkdev->mode = xenstore_read_be_str(xendev, "mode");
677 }
678 if (blkdev->type == NULL) {
679 blkdev->type = xenstore_read_be_str(xendev, "type");
680 }
681 if (blkdev->dev == NULL) {
682 blkdev->dev = xenstore_read_be_str(xendev, "dev");
683 }
684 if (blkdev->devtype == NULL) {
685 blkdev->devtype = xenstore_read_be_str(xendev, "device-type");
686 }
687 directiosafe = xenstore_read_be_str(xendev, "direct-io-safe");
688 blkdev->directiosafe = (directiosafe && atoi(directiosafe));
689
690 /* do we have all we need? */
691 if (blkdev->params == NULL ||
692 blkdev->mode == NULL ||
693 blkdev->type == NULL ||
694 blkdev->dev == NULL) {
695 goto out_error;
696 }
697
698 /* read-only ? */
699 if (strcmp(blkdev->mode, "w")) {
700 info |= VDISK_READONLY;
701 }
702
703 /* cdrom ? */
704 if (blkdev->devtype && !strcmp(blkdev->devtype, "cdrom")) {
705 info |= VDISK_CDROM;
706 }
707
708 blkdev->file_blk = BLOCK_SIZE;
709
710 /* fill info
711 * blk_connect supplies sector-size and sectors
712 */
713 xenstore_write_be_int(xendev, "feature-flush-cache", 1);
714 xenstore_write_be_int(xendev, "info", info);
715
716 xenstore_write_be_int(xendev, "max-ring-page-order",
717 MAX_RING_PAGE_ORDER);
718
719 blk_parse_discard(blkdev);
720
721 g_free(directiosafe);
722 return 0;
723
724 out_error:
725 g_free(blkdev->params);
726 blkdev->params = NULL;
727 g_free(blkdev->mode);
728 blkdev->mode = NULL;
729 g_free(blkdev->type);
730 blkdev->type = NULL;
731 g_free(blkdev->dev);
732 blkdev->dev = NULL;
733 g_free(blkdev->devtype);
734 blkdev->devtype = NULL;
735 g_free(directiosafe);
736 blkdev->directiosafe = false;
737 return -1;
738 }
739
740 static int blk_connect(struct XenLegacyDevice *xendev)
741 {
742 struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
743 int index, qflags;
744 bool readonly = true;
745 bool writethrough = true;
746 int order, ring_ref;
747 unsigned int ring_size, max_grants;
748 unsigned int i;
749
750 trace_xen_disk_connect(xendev->name);
751
752 /* read-only ? */
753 if (blkdev->directiosafe) {
754 qflags = BDRV_O_NOCACHE | BDRV_O_NATIVE_AIO;
755 } else {
756 qflags = 0;
757 writethrough = false;
758 }
759 if (strcmp(blkdev->mode, "w") == 0) {
760 qflags |= BDRV_O_RDWR;
761 readonly = false;
762 }
763 if (blkdev->feature_discard) {
764 qflags |= BDRV_O_UNMAP;
765 }
766
767 /* init qemu block driver */
768 index = (xendev->dev - 202 * 256) / 16;
769 blkdev->dinfo = drive_get(IF_XEN, 0, index);
770 if (!blkdev->dinfo) {
771 Error *local_err = NULL;
772 QDict *options = NULL;
773
774 if (strcmp(blkdev->fileproto, "<unset>")) {
775 options = qdict_new();
776 qdict_put_str(options, "driver", blkdev->fileproto);
777 }
778
779 /* setup via xenbus -> create new block driver instance */
780 xen_pv_printf(xendev, 2, "create new bdrv (xenbus setup)\n");
781 blkdev->blk = blk_new_open(blkdev->filename, NULL, options,
782 qflags, &local_err);
783 if (!blkdev->blk) {
784 xen_pv_printf(xendev, 0, "error: %s\n",
785 error_get_pretty(local_err));
786 error_free(local_err);
787 return -1;
788 }
789 blk_set_enable_write_cache(blkdev->blk, !writethrough);
790 } else {
791 /* setup via qemu cmdline -> already setup for us */
792 xen_pv_printf(xendev, 2,
793 "get configured bdrv (cmdline setup)\n");
794 blkdev->blk = blk_by_legacy_dinfo(blkdev->dinfo);
795 if (blk_is_read_only(blkdev->blk) && !readonly) {
796 xen_pv_printf(xendev, 0, "Unexpected read-only drive");
797 blkdev->blk = NULL;
798 return -1;
799 }
800 /* blkdev->blk is not create by us, we get a reference
801 * so we can blk_unref() unconditionally */
802 blk_ref(blkdev->blk);
803 }
804 blk_attach_dev_legacy(blkdev->blk, blkdev);
805 blkdev->file_size = blk_getlength(blkdev->blk);
806 if (blkdev->file_size < 0) {
807 BlockDriverState *bs = blk_bs(blkdev->blk);
808 const char *drv_name = bs ? bdrv_get_format_name(bs) : NULL;
809 xen_pv_printf(xendev, 1, "blk_getlength: %d (%s) | drv %s\n",
810 (int)blkdev->file_size, strerror(-blkdev->file_size),
811 drv_name ?: "-");
812 blkdev->file_size = 0;
813 }
814
815 xen_pv_printf(xendev, 1, "type \"%s\", fileproto \"%s\", filename \"%s\","
816 " size %" PRId64 " (%" PRId64 " MB)\n",
817 blkdev->type, blkdev->fileproto, blkdev->filename,
818 blkdev->file_size, blkdev->file_size / MiB);
819
820 /* Fill in number of sector size and number of sectors */
821 xenstore_write_be_int(xendev, "sector-size", blkdev->file_blk);
822 xenstore_write_be_int64(xendev, "sectors",
823 blkdev->file_size / blkdev->file_blk);
824
825 if (xenstore_read_fe_int(xendev, "ring-page-order",
826 &order) == -1) {
827 blkdev->nr_ring_ref = 1;
828
829 if (xenstore_read_fe_int(xendev, "ring-ref",
830 &ring_ref) == -1) {
831 return -1;
832 }
833 blkdev->ring_ref[0] = ring_ref;
834
835 } else if (order >= 0 && order <= MAX_RING_PAGE_ORDER) {
836 blkdev->nr_ring_ref = 1 << order;
837
838 for (i = 0; i < blkdev->nr_ring_ref; i++) {
839 char *key;
840
841 key = g_strdup_printf("ring-ref%u", i);
842 if (!key) {
843 return -1;
844 }
845
846 if (xenstore_read_fe_int(xendev, key,
847 &ring_ref) == -1) {
848 g_free(key);
849 return -1;
850 }
851 blkdev->ring_ref[i] = ring_ref;
852
853 g_free(key);
854 }
855 } else {
856 xen_pv_printf(xendev, 0, "invalid ring-page-order: %d\n",
857 order);
858 return -1;
859 }
860
861 if (xenstore_read_fe_int(xendev, "event-channel",
862 &xendev->remote_port) == -1) {
863 return -1;
864 }
865
866 if (!xendev->protocol) {
867 blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
868 } else if (strcmp(xendev->protocol, XEN_IO_PROTO_ABI_NATIVE) == 0) {
869 blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
870 } else if (strcmp(xendev->protocol, XEN_IO_PROTO_ABI_X86_32) == 0) {
871 blkdev->protocol = BLKIF_PROTOCOL_X86_32;
872 } else if (strcmp(xendev->protocol, XEN_IO_PROTO_ABI_X86_64) == 0) {
873 blkdev->protocol = BLKIF_PROTOCOL_X86_64;
874 } else {
875 blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
876 }
877
878 ring_size = XC_PAGE_SIZE * blkdev->nr_ring_ref;
879 switch (blkdev->protocol) {
880 case BLKIF_PROTOCOL_NATIVE:
881 {
882 blkdev->max_requests = __CONST_RING_SIZE(blkif, ring_size);
883 break;
884 }
885 case BLKIF_PROTOCOL_X86_32:
886 {
887 blkdev->max_requests = __CONST_RING_SIZE(blkif_x86_32, ring_size);
888 break;
889 }
890 case BLKIF_PROTOCOL_X86_64:
891 {
892 blkdev->max_requests = __CONST_RING_SIZE(blkif_x86_64, ring_size);
893 break;
894 }
895 default:
896 return -1;
897 }
898
899 /* Add on the number needed for the ring pages */
900 max_grants = blkdev->nr_ring_ref;
901
902 xen_be_set_max_grant_refs(xendev, max_grants);
903 blkdev->sring = xen_be_map_grant_refs(xendev, blkdev->ring_ref,
904 blkdev->nr_ring_ref,
905 PROT_READ | PROT_WRITE);
906 if (!blkdev->sring) {
907 return -1;
908 }
909
910 switch (blkdev->protocol) {
911 case BLKIF_PROTOCOL_NATIVE:
912 {
913 blkif_sring_t *sring_native = blkdev->sring;
914 BACK_RING_INIT(&blkdev->rings.native, sring_native, ring_size);
915 break;
916 }
917 case BLKIF_PROTOCOL_X86_32:
918 {
919 blkif_x86_32_sring_t *sring_x86_32 = blkdev->sring;
920
921 BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, ring_size);
922 break;
923 }
924 case BLKIF_PROTOCOL_X86_64:
925 {
926 blkif_x86_64_sring_t *sring_x86_64 = blkdev->sring;
927
928 BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, ring_size);
929 break;
930 }
931 }
932
933 blk_set_aio_context(blkdev->blk, blkdev->ctx);
934
935 xen_be_bind_evtchn(xendev);
936
937 xen_pv_printf(xendev, 1, "ok: proto %s, nr-ring-ref %u, "
938 "remote port %d, local port %d\n",
939 xendev->protocol, blkdev->nr_ring_ref,
940 xendev->remote_port, xendev->local_port);
941 return 0;
942 }
943
944 static void blk_disconnect(struct XenLegacyDevice *xendev)
945 {
946 struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
947
948 trace_xen_disk_disconnect(xendev->name);
949
950 aio_context_acquire(blkdev->ctx);
951
952 if (blkdev->blk) {
953 blk_set_aio_context(blkdev->blk, qemu_get_aio_context());
954 blk_detach_dev(blkdev->blk, blkdev);
955 blk_unref(blkdev->blk);
956 blkdev->blk = NULL;
957 }
958 xen_pv_unbind_evtchn(xendev);
959
960 aio_context_release(blkdev->ctx);
961
962 if (blkdev->sring) {
963 xen_be_unmap_grant_refs(xendev, blkdev->sring,
964 blkdev->nr_ring_ref);
965 blkdev->sring = NULL;
966 }
967 }
968
969 static int blk_free(struct XenLegacyDevice *xendev)
970 {
971 struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
972 struct ioreq *ioreq;
973
974 trace_xen_disk_free(xendev->name);
975
976 blk_disconnect(xendev);
977
978 while (!QLIST_EMPTY(&blkdev->freelist)) {
979 ioreq = QLIST_FIRST(&blkdev->freelist);
980 QLIST_REMOVE(ioreq, list);
981 qemu_iovec_destroy(&ioreq->v);
982 g_free(ioreq);
983 }
984
985 g_free(blkdev->params);
986 g_free(blkdev->mode);
987 g_free(blkdev->type);
988 g_free(blkdev->dev);
989 g_free(blkdev->devtype);
990 qemu_bh_delete(blkdev->bh);
991 iothread_destroy(blkdev->iothread);
992 return 0;
993 }
994
995 static void blk_event(struct XenLegacyDevice *xendev)
996 {
997 struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
998
999 qemu_bh_schedule(blkdev->bh);
1000 }
1001
1002 struct XenDevOps xen_blkdev_ops = {
1003 .flags = DEVOPS_FLAG_NEED_GNTDEV,
1004 .size = sizeof(struct XenBlkDev),
1005 .alloc = blk_alloc,
1006 .init = blk_init,
1007 .initialise = blk_connect,
1008 .disconnect = blk_disconnect,
1009 .event = blk_event,
1010 .free = blk_free,
1011 };
QEmu