1 /*
2 * XenBSD block device driver
3 *
4 * Copyright (c) 2010-2013 Spectra Logic Corporation
5 * Copyright (c) 2009 Scott Long, Yahoo!
6 * Copyright (c) 2009 Frank Suchomel, Citrix
7 * Copyright (c) 2009 Doug F. Rabson, Citrix
8 * Copyright (c) 2005 Kip Macy
9 * Copyright (c) 2003-2004, Keir Fraser & Steve Hand
10 * Modifications by Mark A. Williamson are (c) Intel Research Cambridge
11 *
12 *
13 * Permission is hereby granted, free of charge, to any person obtaining a copy
14 * of this software and associated documentation files (the "Software"), to
15 * deal in the Software without restriction, including without limitation the
16 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
17 * sell copies of the Software, and to permit persons to whom the Software is
18 * furnished to do so, subject to the following conditions:
19 *
20 * The above copyright notice and this permission notice shall be included in
21 * all copies or substantial portions of the Software.
22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
25 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
27 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
28 * DEALINGS IN THE SOFTWARE.
29 */
30
31 #include <sys/cdefs.h>
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/malloc.h>
35 #include <sys/kernel.h>
36 #include <vm/vm.h>
37 #include <vm/pmap.h>
38
39 #include <sys/bio.h>
40 #include <sys/bus.h>
41 #include <sys/conf.h>
42 #include <sys/module.h>
43 #include <sys/sysctl.h>
44
45 #include <machine/bus.h>
46 #include <sys/rman.h>
47 #include <machine/resource.h>
48 #include <machine/vmparam.h>
49
50 #include <xen/xen-os.h>
51 #include <xen/hypervisor.h>
52 #include <xen/xen_intr.h>
53 #include <xen/gnttab.h>
54 #include <contrib/xen/grant_table.h>
55 #include <contrib/xen/io/protocols.h>
56 #include <xen/xenbus/xenbusvar.h>
57
58 #include <machine/_inttypes.h>
59
60 #include <geom/geom_disk.h>
61
62 #include <dev/xen/blkfront/block.h>
63
64 #include "xenbus_if.h"
65
66 /*--------------------------- Forward Declarations ---------------------------*/
67 static void xbd_closing(device_t);
68 static void xbd_startio(struct xbd_softc *sc);
69
70 /*---------------------------------- Macros ----------------------------------*/
71 #if 0
72 #define DPRINTK(fmt, args...) printf("[XEN] %s:%d: " fmt ".\n", __func__, __LINE__, ##args)
73 #else
74 #define DPRINTK(fmt, args...)
75 #endif
76
77 #define XBD_SECTOR_SHFT 9
78
79 /*---------------------------- Global Static Data ----------------------------*/
80 static MALLOC_DEFINE(M_XENBLOCKFRONT, "xbd", "Xen Block Front driver data");
81
82 static int xbd_enable_indirect = 1;
83 SYSCTL_NODE(_hw, OID_AUTO, xbd, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
84 "xbd driver parameters");
85 SYSCTL_INT(_hw_xbd, OID_AUTO, xbd_enable_indirect, CTLFLAG_RDTUN,
86 &xbd_enable_indirect, 0, "Enable xbd indirect segments");
87
88 /*---------------------------- Command Processing ----------------------------*/
89 static void
xbd_freeze(struct xbd_softc * sc,xbd_flag_t xbd_flag)90 xbd_freeze(struct xbd_softc *sc, xbd_flag_t xbd_flag)
91 {
92 if (xbd_flag != XBDF_NONE && (sc->xbd_flags & xbd_flag) != 0)
93 return;
94
95 sc->xbd_flags |= xbd_flag;
96 sc->xbd_qfrozen_cnt++;
97 }
98
99 static void
xbd_thaw(struct xbd_softc * sc,xbd_flag_t xbd_flag)100 xbd_thaw(struct xbd_softc *sc, xbd_flag_t xbd_flag)
101 {
102 if (xbd_flag != XBDF_NONE && (sc->xbd_flags & xbd_flag) == 0)
103 return;
104
105 if (sc->xbd_qfrozen_cnt == 0)
106 panic("%s: Thaw with flag 0x%x while not frozen.",
107 __func__, xbd_flag);
108
109 sc->xbd_flags &= ~xbd_flag;
110 sc->xbd_qfrozen_cnt--;
111 }
112
113 static void
xbd_cm_freeze(struct xbd_softc * sc,struct xbd_command * cm,xbdc_flag_t cm_flag)114 xbd_cm_freeze(struct xbd_softc *sc, struct xbd_command *cm, xbdc_flag_t cm_flag)
115 {
116 if ((cm->cm_flags & XBDCF_FROZEN) != 0)
117 return;
118
119 cm->cm_flags |= XBDCF_FROZEN|cm_flag;
120 xbd_freeze(sc, XBDF_NONE);
121 }
122
123 static void
xbd_cm_thaw(struct xbd_softc * sc,struct xbd_command * cm)124 xbd_cm_thaw(struct xbd_softc *sc, struct xbd_command *cm)
125 {
126 if ((cm->cm_flags & XBDCF_FROZEN) == 0)
127 return;
128
129 cm->cm_flags &= ~XBDCF_FROZEN;
130 xbd_thaw(sc, XBDF_NONE);
131 }
132
133 static inline void
xbd_flush_requests(struct xbd_softc * sc)134 xbd_flush_requests(struct xbd_softc *sc)
135 {
136 int notify;
137
138 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&sc->xbd_ring, notify);
139
140 if (notify)
141 xen_intr_signal(sc->xen_intr_handle);
142 }
143
144 static void
xbd_free_command(struct xbd_command * cm)145 xbd_free_command(struct xbd_command *cm)
146 {
147
148 KASSERT((cm->cm_flags & XBDCF_Q_MASK) == XBD_Q_NONE,
149 ("Freeing command that is still on queue %d.",
150 cm->cm_flags & XBDCF_Q_MASK));
151
152 cm->cm_flags = XBDCF_INITIALIZER;
153 cm->cm_bp = NULL;
154 cm->cm_complete = NULL;
155 xbd_enqueue_cm(cm, XBD_Q_FREE);
156 xbd_thaw(cm->cm_sc, XBDF_CM_SHORTAGE);
157 }
158
159 static void
xbd_mksegarray(bus_dma_segment_t * segs,int nsegs,grant_ref_t * gref_head,int otherend_id,int readonly,grant_ref_t * sg_ref,struct blkif_request_segment * sg,unsigned int sector_size)160 xbd_mksegarray(bus_dma_segment_t *segs, int nsegs,
161 grant_ref_t * gref_head, int otherend_id, int readonly,
162 grant_ref_t * sg_ref, struct blkif_request_segment *sg,
163 unsigned int sector_size)
164 {
165 struct blkif_request_segment *last_block_sg = sg + nsegs;
166 vm_paddr_t buffer_ma;
167 uint64_t fsect, lsect;
168 int ref;
169
170 while (sg < last_block_sg) {
171 KASSERT((segs->ds_addr & (sector_size - 1)) == 0,
172 ("XEN disk driver I/O must be sector aligned"));
173 KASSERT((segs->ds_len & (sector_size - 1)) == 0,
174 ("XEN disk driver I/Os must be a multiple of "
175 "the sector length"));
176 buffer_ma = segs->ds_addr;
177 fsect = (buffer_ma & PAGE_MASK) >> XBD_SECTOR_SHFT;
178 lsect = fsect + (segs->ds_len >> XBD_SECTOR_SHFT) - 1;
179
180 KASSERT(lsect <= 7, ("XEN disk driver data cannot "
181 "cross a page boundary"));
182
183 /* install a grant reference. */
184 ref = gnttab_claim_grant_reference(gref_head);
185
186 /*
187 * GNTTAB_LIST_END == 0xffffffff, but it is private
188 * to gnttab.c.
189 */
190 KASSERT(ref != ~0, ("grant_reference failed"));
191
192 gnttab_grant_foreign_access_ref(
193 ref,
194 otherend_id,
195 buffer_ma >> PAGE_SHIFT,
196 readonly);
197
198 *sg_ref = ref;
199 *sg = (struct blkif_request_segment) {
200 .gref = ref,
201 .first_sect = fsect,
202 .last_sect = lsect
203 };
204 sg++;
205 sg_ref++;
206 segs++;
207 }
208 }
209
210 static void
xbd_queue_cb(void * arg,bus_dma_segment_t * segs,int nsegs,int error)211 xbd_queue_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
212 {
213 struct xbd_softc *sc;
214 struct xbd_command *cm;
215 int op;
216
217 cm = arg;
218 sc = cm->cm_sc;
219
220 if (error) {
221 cm->cm_bp->bio_error = EIO;
222 biodone(cm->cm_bp);
223 xbd_free_command(cm);
224 return;
225 }
226
227 KASSERT(nsegs <= sc->xbd_max_request_segments,
228 ("Too many segments in a blkfront I/O"));
229
230 if (nsegs <= BLKIF_MAX_SEGMENTS_PER_REQUEST) {
231 blkif_request_t *ring_req;
232
233 /* Fill out a blkif_request_t structure. */
234 ring_req = (blkif_request_t *)
235 RING_GET_REQUEST(&sc->xbd_ring, sc->xbd_ring.req_prod_pvt);
236 sc->xbd_ring.req_prod_pvt++;
237 ring_req->id = cm->cm_id;
238 ring_req->operation = cm->cm_operation;
239 ring_req->sector_number = cm->cm_sector_number;
240 ring_req->handle = (blkif_vdev_t)(uintptr_t)sc->xbd_disk;
241 ring_req->nr_segments = nsegs;
242 cm->cm_nseg = nsegs;
243 xbd_mksegarray(segs, nsegs, &cm->cm_gref_head,
244 xenbus_get_otherend_id(sc->xbd_dev),
245 cm->cm_operation == BLKIF_OP_WRITE,
246 cm->cm_sg_refs, ring_req->seg,
247 sc->xbd_disk->d_sectorsize);
248 } else {
249 blkif_request_indirect_t *ring_req;
250
251 /* Fill out a blkif_request_indirect_t structure. */
252 ring_req = (blkif_request_indirect_t *)
253 RING_GET_REQUEST(&sc->xbd_ring, sc->xbd_ring.req_prod_pvt);
254 sc->xbd_ring.req_prod_pvt++;
255 ring_req->id = cm->cm_id;
256 ring_req->operation = BLKIF_OP_INDIRECT;
257 ring_req->indirect_op = cm->cm_operation;
258 ring_req->sector_number = cm->cm_sector_number;
259 ring_req->handle = (blkif_vdev_t)(uintptr_t)sc->xbd_disk;
260 ring_req->nr_segments = nsegs;
261 cm->cm_nseg = nsegs;
262 xbd_mksegarray(segs, nsegs, &cm->cm_gref_head,
263 xenbus_get_otherend_id(sc->xbd_dev),
264 cm->cm_operation == BLKIF_OP_WRITE,
265 cm->cm_sg_refs, cm->cm_indirectionpages,
266 sc->xbd_disk->d_sectorsize);
267 memcpy(ring_req->indirect_grefs, &cm->cm_indirectionrefs,
268 sizeof(grant_ref_t) * sc->xbd_max_request_indirectpages);
269 }
270
271 if (cm->cm_operation == BLKIF_OP_READ)
272 op = BUS_DMASYNC_PREREAD;
273 else if (cm->cm_operation == BLKIF_OP_WRITE)
274 op = BUS_DMASYNC_PREWRITE;
275 else
276 op = 0;
277 bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op);
278
279 gnttab_free_grant_references(cm->cm_gref_head);
280
281 xbd_enqueue_cm(cm, XBD_Q_BUSY);
282
283 /*
284 * If bus dma had to asynchronously call us back to dispatch
285 * this command, we are no longer executing in the context of
286 * xbd_startio(). Thus we cannot rely on xbd_startio()'s call to
287 * xbd_flush_requests() to publish this command to the backend
288 * along with any other commands that it could batch.
289 */
290 if ((cm->cm_flags & XBDCF_ASYNC_MAPPING) != 0)
291 xbd_flush_requests(sc);
292
293 return;
294 }
295
296 static int
xbd_queue_request(struct xbd_softc * sc,struct xbd_command * cm)297 xbd_queue_request(struct xbd_softc *sc, struct xbd_command *cm)
298 {
299 int error;
300
301 if (cm->cm_bp != NULL)
302 error = bus_dmamap_load_bio(sc->xbd_io_dmat, cm->cm_map,
303 cm->cm_bp, xbd_queue_cb, cm, 0);
304 else
305 error = bus_dmamap_load(sc->xbd_io_dmat, cm->cm_map,
306 cm->cm_data, cm->cm_datalen, xbd_queue_cb, cm, 0);
307 if (error == EINPROGRESS) {
308 /*
309 * Maintain queuing order by freezing the queue. The next
310 * command may not require as many resources as the command
311 * we just attempted to map, so we can't rely on bus dma
312 * blocking for it too.
313 */
314 xbd_cm_freeze(sc, cm, XBDCF_ASYNC_MAPPING);
315 return (0);
316 }
317
318 return (error);
319 }
320
321 static void
xbd_restart_queue_callback(void * arg)322 xbd_restart_queue_callback(void *arg)
323 {
324 struct xbd_softc *sc = arg;
325
326 mtx_lock(&sc->xbd_io_lock);
327
328 xbd_thaw(sc, XBDF_GNT_SHORTAGE);
329
330 xbd_startio(sc);
331
332 mtx_unlock(&sc->xbd_io_lock);
333 }
334
335 static struct xbd_command *
xbd_bio_command(struct xbd_softc * sc)336 xbd_bio_command(struct xbd_softc *sc)
337 {
338 struct xbd_command *cm;
339 struct bio *bp;
340
341 if (__predict_false(sc->xbd_state != XBD_STATE_CONNECTED))
342 return (NULL);
343
344 bp = xbd_dequeue_bio(sc);
345 if (bp == NULL)
346 return (NULL);
347
348 if ((cm = xbd_dequeue_cm(sc, XBD_Q_FREE)) == NULL) {
349 xbd_freeze(sc, XBDF_CM_SHORTAGE);
350 xbd_requeue_bio(sc, bp);
351 return (NULL);
352 }
353
354 if (gnttab_alloc_grant_references(sc->xbd_max_request_segments,
355 &cm->cm_gref_head) != 0) {
356 gnttab_request_free_callback(&sc->xbd_callback,
357 xbd_restart_queue_callback, sc,
358 sc->xbd_max_request_segments);
359 xbd_freeze(sc, XBDF_GNT_SHORTAGE);
360 xbd_requeue_bio(sc, bp);
361 xbd_enqueue_cm(cm, XBD_Q_FREE);
362 return (NULL);
363 }
364
365 cm->cm_bp = bp;
366 cm->cm_sector_number =
367 ((blkif_sector_t)bp->bio_pblkno * sc->xbd_disk->d_sectorsize) >>
368 XBD_SECTOR_SHFT;
369
370 switch (bp->bio_cmd) {
371 case BIO_READ:
372 cm->cm_operation = BLKIF_OP_READ;
373 break;
374 case BIO_WRITE:
375 cm->cm_operation = BLKIF_OP_WRITE;
376 if ((bp->bio_flags & BIO_ORDERED) != 0) {
377 if ((sc->xbd_flags & XBDF_BARRIER) != 0) {
378 cm->cm_operation = BLKIF_OP_WRITE_BARRIER;
379 } else {
380 /*
381 * Single step this command.
382 */
383 cm->cm_flags |= XBDCF_Q_FREEZE;
384 if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
385 /*
386 * Wait for in-flight requests to
387 * finish.
388 */
389 xbd_freeze(sc, XBDF_WAIT_IDLE);
390 xbd_requeue_cm(cm, XBD_Q_READY);
391 return (NULL);
392 }
393 }
394 }
395 break;
396 case BIO_FLUSH:
397 if ((sc->xbd_flags & XBDF_FLUSH) != 0)
398 cm->cm_operation = BLKIF_OP_FLUSH_DISKCACHE;
399 else if ((sc->xbd_flags & XBDF_BARRIER) != 0)
400 cm->cm_operation = BLKIF_OP_WRITE_BARRIER;
401 else
402 panic("flush request, but no flush support available");
403 break;
404 default:
405 biofinish(bp, NULL, EOPNOTSUPP);
406 xbd_enqueue_cm(cm, XBD_Q_FREE);
407 return (NULL);
408 }
409
410 return (cm);
411 }
412
413 /*
414 * Dequeue buffers and place them in the shared communication ring.
415 * Return when no more requests can be accepted or all buffers have
416 * been queued.
417 *
418 * Signal XEN once the ring has been filled out.
419 */
420 static void
xbd_startio(struct xbd_softc * sc)421 xbd_startio(struct xbd_softc *sc)
422 {
423 struct xbd_command *cm;
424 int error, queued = 0;
425
426 mtx_assert(&sc->xbd_io_lock, MA_OWNED);
427
428 if (sc->xbd_state != XBD_STATE_CONNECTED)
429 return;
430
431 while (!RING_FULL(&sc->xbd_ring)) {
432 if (sc->xbd_qfrozen_cnt != 0)
433 break;
434
435 cm = xbd_dequeue_cm(sc, XBD_Q_READY);
436
437 if (cm == NULL)
438 cm = xbd_bio_command(sc);
439
440 if (cm == NULL)
441 break;
442
443 if ((cm->cm_flags & XBDCF_Q_FREEZE) != 0) {
444 /*
445 * Single step command. Future work is
446 * held off until this command completes.
447 */
448 xbd_cm_freeze(sc, cm, XBDCF_Q_FREEZE);
449 }
450
451 if ((error = xbd_queue_request(sc, cm)) != 0) {
452 printf("xbd_queue_request returned %d\n", error);
453 break;
454 }
455 queued++;
456 }
457
458 if (queued != 0)
459 xbd_flush_requests(sc);
460 }
461
462 static void
xbd_bio_complete(struct xbd_softc * sc,struct xbd_command * cm)463 xbd_bio_complete(struct xbd_softc *sc, struct xbd_command *cm)
464 {
465 struct bio *bp;
466
467 bp = cm->cm_bp;
468
469 if (__predict_false(cm->cm_status != BLKIF_RSP_OKAY)) {
470 disk_err(bp, "disk error" , -1, 0);
471 printf(" status: %x\n", cm->cm_status);
472 bp->bio_flags |= BIO_ERROR;
473 }
474
475 if (bp->bio_flags & BIO_ERROR)
476 bp->bio_error = EIO;
477 else
478 bp->bio_resid = 0;
479
480 xbd_free_command(cm);
481 biodone(bp);
482 }
483
484 static void
xbd_int(void * xsc)485 xbd_int(void *xsc)
486 {
487 struct xbd_softc *sc = xsc;
488 struct xbd_command *cm;
489 blkif_response_t *bret;
490 RING_IDX i, rp;
491 int op;
492
493 mtx_lock(&sc->xbd_io_lock);
494
495 if (__predict_false(sc->xbd_state == XBD_STATE_DISCONNECTED)) {
496 mtx_unlock(&sc->xbd_io_lock);
497 return;
498 }
499
500 again:
501 rp = sc->xbd_ring.sring->rsp_prod;
502 rmb(); /* Ensure we see queued responses up to 'rp'. */
503
504 for (i = sc->xbd_ring.rsp_cons; i != rp;) {
505 bret = RING_GET_RESPONSE(&sc->xbd_ring, i);
506 cm = &sc->xbd_shadow[bret->id];
507
508 xbd_remove_cm(cm, XBD_Q_BUSY);
509 gnttab_end_foreign_access_references(cm->cm_nseg,
510 cm->cm_sg_refs);
511 i++;
512
513 if (cm->cm_operation == BLKIF_OP_READ)
514 op = BUS_DMASYNC_POSTREAD;
515 else if (cm->cm_operation == BLKIF_OP_WRITE ||
516 cm->cm_operation == BLKIF_OP_WRITE_BARRIER)
517 op = BUS_DMASYNC_POSTWRITE;
518 else
519 op = 0;
520 bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op);
521 bus_dmamap_unload(sc->xbd_io_dmat, cm->cm_map);
522
523 /*
524 * Release any hold this command has on future command
525 * dispatch.
526 */
527 xbd_cm_thaw(sc, cm);
528
529 /*
530 * Directly call the i/o complete routine to save an
531 * an indirection in the common case.
532 */
533 cm->cm_status = bret->status;
534 if (cm->cm_bp)
535 xbd_bio_complete(sc, cm);
536 else if (cm->cm_complete != NULL)
537 cm->cm_complete(cm);
538 else
539 xbd_free_command(cm);
540 }
541
542 sc->xbd_ring.rsp_cons = i;
543
544 if (i != sc->xbd_ring.req_prod_pvt) {
545 int more_to_do;
546 RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, more_to_do);
547 if (more_to_do)
548 goto again;
549 } else {
550 sc->xbd_ring.sring->rsp_event = i + 1;
551 }
552
553 if (xbd_queue_length(sc, XBD_Q_BUSY) == 0)
554 xbd_thaw(sc, XBDF_WAIT_IDLE);
555
556 xbd_startio(sc);
557
558 if (__predict_false(sc->xbd_state == XBD_STATE_SUSPENDED))
559 wakeup(&sc->xbd_cm_q[XBD_Q_BUSY]);
560
561 mtx_unlock(&sc->xbd_io_lock);
562 }
563
564 /*------------------------------- Dump Support -------------------------------*/
565 /**
566 * Quiesce the disk writes for a dump file before allowing the next buffer.
567 */
568 static void
xbd_quiesce(struct xbd_softc * sc)569 xbd_quiesce(struct xbd_softc *sc)
570 {
571 int mtd;
572
573 // While there are outstanding requests
574 while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
575 RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, mtd);
576 if (mtd) {
577 /* Received request completions, update queue. */
578 xbd_int(sc);
579 }
580 if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
581 /*
582 * Still pending requests, wait for the disk i/o
583 * to complete.
584 */
585 HYPERVISOR_yield();
586 }
587 }
588 }
589
590 /* Kernel dump function for a paravirtualized disk device */
591 static void
xbd_dump_complete(struct xbd_command * cm)592 xbd_dump_complete(struct xbd_command *cm)
593 {
594
595 xbd_enqueue_cm(cm, XBD_Q_COMPLETE);
596 }
597
598 static int
xbd_dump(void * arg,void * virtual,off_t offset,size_t length)599 xbd_dump(void *arg, void *virtual, off_t offset, size_t length)
600 {
601 struct disk *dp = arg;
602 struct xbd_softc *sc = dp->d_drv1;
603 struct xbd_command *cm;
604 size_t chunk;
605 int rc = 0;
606
607 if (length == 0)
608 return (0);
609
610 xbd_quiesce(sc); /* All quiet on the western front. */
611
612 /*
613 * If this lock is held, then this module is failing, and a
614 * successful kernel dump is highly unlikely anyway.
615 */
616 mtx_lock(&sc->xbd_io_lock);
617
618 /* Split the 64KB block as needed */
619 while (length > 0) {
620 cm = xbd_dequeue_cm(sc, XBD_Q_FREE);
621 if (cm == NULL) {
622 mtx_unlock(&sc->xbd_io_lock);
623 device_printf(sc->xbd_dev, "dump: no more commands?\n");
624 return (EBUSY);
625 }
626
627 if (gnttab_alloc_grant_references(sc->xbd_max_request_segments,
628 &cm->cm_gref_head) != 0) {
629 xbd_free_command(cm);
630 mtx_unlock(&sc->xbd_io_lock);
631 device_printf(sc->xbd_dev, "no more grant allocs?\n");
632 return (EBUSY);
633 }
634
635 chunk = length > sc->xbd_max_request_size ?
636 sc->xbd_max_request_size : length;
637 cm->cm_data = virtual;
638 cm->cm_datalen = chunk;
639 cm->cm_operation = BLKIF_OP_WRITE;
640 cm->cm_sector_number = offset >> XBD_SECTOR_SHFT;
641 cm->cm_complete = xbd_dump_complete;
642
643 xbd_enqueue_cm(cm, XBD_Q_READY);
644
645 length -= chunk;
646 offset += chunk;
647 virtual = (char *) virtual + chunk;
648 }
649
650 /* Tell DOM0 to do the I/O */
651 xbd_startio(sc);
652 mtx_unlock(&sc->xbd_io_lock);
653
654 /* Poll for the completion. */
655 xbd_quiesce(sc); /* All quite on the eastern front */
656
657 /* If there were any errors, bail out... */
658 while ((cm = xbd_dequeue_cm(sc, XBD_Q_COMPLETE)) != NULL) {
659 if (cm->cm_status != BLKIF_RSP_OKAY) {
660 device_printf(sc->xbd_dev,
661 "Dump I/O failed at sector %jd\n",
662 cm->cm_sector_number);
663 rc = EIO;
664 }
665 xbd_free_command(cm);
666 }
667
668 return (rc);
669 }
670
671 /*----------------------------- Disk Entrypoints -----------------------------*/
672 static int
xbd_open(struct disk * dp)673 xbd_open(struct disk *dp)
674 {
675 struct xbd_softc *sc = dp->d_drv1;
676
677 if (sc == NULL) {
678 printf("xbd%d: not found", dp->d_unit);
679 return (ENXIO);
680 }
681
682 sc->xbd_flags |= XBDF_OPEN;
683 sc->xbd_users++;
684 return (0);
685 }
686
687 static int
xbd_close(struct disk * dp)688 xbd_close(struct disk *dp)
689 {
690 struct xbd_softc *sc = dp->d_drv1;
691
692 if (sc == NULL)
693 return (ENXIO);
694 sc->xbd_flags &= ~XBDF_OPEN;
695 if (--(sc->xbd_users) == 0) {
696 /*
697 * Check whether we have been instructed to close. We will
698 * have ignored this request initially, as the device was
699 * still mounted.
700 */
701 if (xenbus_get_otherend_state(sc->xbd_dev) ==
702 XenbusStateClosing)
703 xbd_closing(sc->xbd_dev);
704 }
705 return (0);
706 }
707
708 static int
xbd_ioctl(struct disk * dp,u_long cmd,void * addr,int flag,struct thread * td)709 xbd_ioctl(struct disk *dp, u_long cmd, void *addr, int flag, struct thread *td)
710 {
711 struct xbd_softc *sc = dp->d_drv1;
712
713 if (sc == NULL)
714 return (ENXIO);
715
716 return (ENOTTY);
717 }
718
719 /*
720 * Read/write routine for a buffer. Finds the proper unit, place it on
721 * the sortq and kick the controller.
722 */
723 static void
xbd_strategy(struct bio * bp)724 xbd_strategy(struct bio *bp)
725 {
726 struct xbd_softc *sc = bp->bio_disk->d_drv1;
727
728 /* bogus disk? */
729 if (sc == NULL) {
730 bp->bio_error = EINVAL;
731 bp->bio_flags |= BIO_ERROR;
732 bp->bio_resid = bp->bio_bcount;
733 biodone(bp);
734 return;
735 }
736
737 /*
738 * Place it in the queue of disk activities for this disk
739 */
740 mtx_lock(&sc->xbd_io_lock);
741
742 xbd_enqueue_bio(sc, bp);
743 xbd_startio(sc);
744
745 mtx_unlock(&sc->xbd_io_lock);
746 return;
747 }
748
749 /*------------------------------ Ring Management -----------------------------*/
750 static int
xbd_alloc_ring(struct xbd_softc * sc)751 xbd_alloc_ring(struct xbd_softc *sc)
752 {
753 blkif_sring_t *sring;
754 uintptr_t sring_page_addr;
755 int error;
756 int i;
757
758 sring = malloc(sc->xbd_ring_pages * PAGE_SIZE, M_XENBLOCKFRONT,
759 M_NOWAIT|M_ZERO);
760 if (sring == NULL) {
761 xenbus_dev_fatal(sc->xbd_dev, ENOMEM, "allocating shared ring");
762 return (ENOMEM);
763 }
764 SHARED_RING_INIT(sring);
765 FRONT_RING_INIT(&sc->xbd_ring, sring, sc->xbd_ring_pages * PAGE_SIZE);
766
767 for (i = 0, sring_page_addr = (uintptr_t)sring;
768 i < sc->xbd_ring_pages;
769 i++, sring_page_addr += PAGE_SIZE) {
770 error = xenbus_grant_ring(sc->xbd_dev,
771 (vtophys(sring_page_addr) >> PAGE_SHIFT),
772 &sc->xbd_ring_ref[i]);
773 if (error) {
774 xenbus_dev_fatal(sc->xbd_dev, error,
775 "granting ring_ref(%d)", i);
776 return (error);
777 }
778 }
779 if (sc->xbd_ring_pages == 1) {
780 error = xs_printf(XST_NIL, xenbus_get_node(sc->xbd_dev),
781 "ring-ref", "%u", sc->xbd_ring_ref[0]);
782 if (error) {
783 xenbus_dev_fatal(sc->xbd_dev, error,
784 "writing %s/ring-ref",
785 xenbus_get_node(sc->xbd_dev));
786 return (error);
787 }
788 } else {
789 for (i = 0; i < sc->xbd_ring_pages; i++) {
790 char ring_ref_name[]= "ring_refXX";
791
792 snprintf(ring_ref_name, sizeof(ring_ref_name),
793 "ring-ref%u", i);
794 error = xs_printf(XST_NIL, xenbus_get_node(sc->xbd_dev),
795 ring_ref_name, "%u", sc->xbd_ring_ref[i]);
796 if (error) {
797 xenbus_dev_fatal(sc->xbd_dev, error,
798 "writing %s/%s",
799 xenbus_get_node(sc->xbd_dev),
800 ring_ref_name);
801 return (error);
802 }
803 }
804 }
805
806 error = xen_intr_alloc_and_bind_local_port(sc->xbd_dev,
807 xenbus_get_otherend_id(sc->xbd_dev), NULL, xbd_int, sc,
808 INTR_TYPE_BIO | INTR_MPSAFE, &sc->xen_intr_handle);
809 if (error) {
810 xenbus_dev_fatal(sc->xbd_dev, error,
811 "xen_intr_alloc_and_bind_local_port failed");
812 return (error);
813 }
814
815 return (0);
816 }
817
818 static void
xbd_free_ring(struct xbd_softc * sc)819 xbd_free_ring(struct xbd_softc *sc)
820 {
821 int i;
822
823 if (sc->xbd_ring.sring == NULL)
824 return;
825
826 for (i = 0; i < sc->xbd_ring_pages; i++) {
827 if (sc->xbd_ring_ref[i] != GRANT_REF_INVALID) {
828 gnttab_end_foreign_access_ref(sc->xbd_ring_ref[i]);
829 sc->xbd_ring_ref[i] = GRANT_REF_INVALID;
830 }
831 }
832 free(sc->xbd_ring.sring, M_XENBLOCKFRONT);
833 sc->xbd_ring.sring = NULL;
834 }
835
836 /*-------------------------- Initialization/Teardown -------------------------*/
837 static int
xbd_feature_string(struct xbd_softc * sc,char * features,size_t len)838 xbd_feature_string(struct xbd_softc *sc, char *features, size_t len)
839 {
840 struct sbuf sb;
841 int feature_cnt;
842
843 sbuf_new(&sb, features, len, SBUF_FIXEDLEN);
844
845 feature_cnt = 0;
846 if ((sc->xbd_flags & XBDF_FLUSH) != 0) {
847 sbuf_printf(&sb, "flush");
848 feature_cnt++;
849 }
850
851 if ((sc->xbd_flags & XBDF_BARRIER) != 0) {
852 if (feature_cnt != 0)
853 sbuf_printf(&sb, ", ");
854 sbuf_printf(&sb, "write_barrier");
855 feature_cnt++;
856 }
857
858 if ((sc->xbd_flags & XBDF_DISCARD) != 0) {
859 if (feature_cnt != 0)
860 sbuf_printf(&sb, ", ");
861 sbuf_printf(&sb, "discard");
862 feature_cnt++;
863 }
864
865 if ((sc->xbd_flags & XBDF_PERSISTENT) != 0) {
866 if (feature_cnt != 0)
867 sbuf_printf(&sb, ", ");
868 sbuf_printf(&sb, "persistent_grants");
869 feature_cnt++;
870 }
871
872 (void) sbuf_finish(&sb);
873 return (sbuf_len(&sb));
874 }
875
876 static int
xbd_sysctl_features(SYSCTL_HANDLER_ARGS)877 xbd_sysctl_features(SYSCTL_HANDLER_ARGS)
878 {
879 char features[80];
880 struct xbd_softc *sc = arg1;
881 int error;
882 int len;
883
884 error = sysctl_wire_old_buffer(req, 0);
885 if (error != 0)
886 return (error);
887
888 len = xbd_feature_string(sc, features, sizeof(features));
889
890 /* len is -1 on error, which will make the SYSCTL_OUT a no-op. */
891 return (SYSCTL_OUT(req, features, len + 1/*NUL*/));
892 }
893
894 static void
xbd_setup_sysctl(struct xbd_softc * xbd)895 xbd_setup_sysctl(struct xbd_softc *xbd)
896 {
897 struct sysctl_ctx_list *sysctl_ctx = NULL;
898 struct sysctl_oid *sysctl_tree = NULL;
899 struct sysctl_oid_list *children;
900
901 sysctl_ctx = device_get_sysctl_ctx(xbd->xbd_dev);
902 if (sysctl_ctx == NULL)
903 return;
904
905 sysctl_tree = device_get_sysctl_tree(xbd->xbd_dev);
906 if (sysctl_tree == NULL)
907 return;
908
909 children = SYSCTL_CHILDREN(sysctl_tree);
910 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO,
911 "max_requests", CTLFLAG_RD, &xbd->xbd_max_requests, -1,
912 "maximum outstanding requests (negotiated)");
913
914 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO,
915 "max_request_segments", CTLFLAG_RD,
916 &xbd->xbd_max_request_segments, 0,
917 "maximum number of pages per requests (negotiated)");
918
919 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO,
920 "max_request_size", CTLFLAG_RD, &xbd->xbd_max_request_size, 0,
921 "maximum size in bytes of a request (negotiated)");
922
923 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO,
924 "ring_pages", CTLFLAG_RD, &xbd->xbd_ring_pages, 0,
925 "communication channel pages (negotiated)");
926
927 SYSCTL_ADD_PROC(sysctl_ctx, children, OID_AUTO,
928 "features", CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, xbd,
929 0, xbd_sysctl_features, "A", "protocol features (negotiated)");
930 }
931
932 /*
933 * Translate Linux major/minor to an appropriate name and unit
934 * number. For HVM guests, this allows us to use the same drive names
935 * with blkfront as the emulated drives, easing transition slightly.
936 */
937 static void
xbd_vdevice_to_unit(uint32_t vdevice,int * unit,const char ** name)938 xbd_vdevice_to_unit(uint32_t vdevice, int *unit, const char **name)
939 {
940 static struct vdev_info {
941 int major;
942 int shift;
943 int base;
944 const char *name;
945 } info[] = {
946 {3, 6, 0, "ada"}, /* ide0 */
947 {22, 6, 2, "ada"}, /* ide1 */
948 {33, 6, 4, "ada"}, /* ide2 */
949 {34, 6, 6, "ada"}, /* ide3 */
950 {56, 6, 8, "ada"}, /* ide4 */
951 {57, 6, 10, "ada"}, /* ide5 */
952 {88, 6, 12, "ada"}, /* ide6 */
953 {89, 6, 14, "ada"}, /* ide7 */
954 {90, 6, 16, "ada"}, /* ide8 */
955 {91, 6, 18, "ada"}, /* ide9 */
956
957 {8, 4, 0, "da"}, /* scsi disk0 */
958 {65, 4, 16, "da"}, /* scsi disk1 */
959 {66, 4, 32, "da"}, /* scsi disk2 */
960 {67, 4, 48, "da"}, /* scsi disk3 */
961 {68, 4, 64, "da"}, /* scsi disk4 */
962 {69, 4, 80, "da"}, /* scsi disk5 */
963 {70, 4, 96, "da"}, /* scsi disk6 */
964 {71, 4, 112, "da"}, /* scsi disk7 */
965 {128, 4, 128, "da"}, /* scsi disk8 */
966 {129, 4, 144, "da"}, /* scsi disk9 */
967 {130, 4, 160, "da"}, /* scsi disk10 */
968 {131, 4, 176, "da"}, /* scsi disk11 */
969 {132, 4, 192, "da"}, /* scsi disk12 */
970 {133, 4, 208, "da"}, /* scsi disk13 */
971 {134, 4, 224, "da"}, /* scsi disk14 */
972 {135, 4, 240, "da"}, /* scsi disk15 */
973
974 {202, 4, 0, "xbd"}, /* xbd */
975
976 {0, 0, 0, NULL},
977 };
978 int major = vdevice >> 8;
979 int minor = vdevice & 0xff;
980 int i;
981
982 if (vdevice & (1 << 28)) {
983 *unit = (vdevice & ((1 << 28) - 1)) >> 8;
984 *name = "xbd";
985 return;
986 }
987
988 for (i = 0; info[i].major; i++) {
989 if (info[i].major == major) {
990 *unit = info[i].base + (minor >> info[i].shift);
991 *name = info[i].name;
992 return;
993 }
994 }
995
996 *unit = minor >> 4;
997 *name = "xbd";
998 }
999
1000 int
xbd_instance_create(struct xbd_softc * sc,blkif_sector_t sectors,int vdevice,uint16_t vdisk_info,unsigned long sector_size,unsigned long phys_sector_size)1001 xbd_instance_create(struct xbd_softc *sc, blkif_sector_t sectors,
1002 int vdevice, uint16_t vdisk_info, unsigned long sector_size,
1003 unsigned long phys_sector_size)
1004 {
1005 char features[80];
1006 int unit, error = 0;
1007 const char *name;
1008
1009 xbd_vdevice_to_unit(vdevice, &unit, &name);
1010
1011 sc->xbd_unit = unit;
1012
1013 if (strcmp(name, "xbd") != 0)
1014 device_printf(sc->xbd_dev, "attaching as %s%d\n", name, unit);
1015
1016 if (xbd_feature_string(sc, features, sizeof(features)) > 0) {
1017 device_printf(sc->xbd_dev, "features: %s\n",
1018 features);
1019 }
1020
1021 sc->xbd_disk = disk_alloc();
1022 sc->xbd_disk->d_unit = sc->xbd_unit;
1023 sc->xbd_disk->d_open = xbd_open;
1024 sc->xbd_disk->d_close = xbd_close;
1025 sc->xbd_disk->d_ioctl = xbd_ioctl;
1026 sc->xbd_disk->d_strategy = xbd_strategy;
1027 sc->xbd_disk->d_dump = xbd_dump;
1028 sc->xbd_disk->d_name = name;
1029 sc->xbd_disk->d_drv1 = sc;
1030 sc->xbd_disk->d_sectorsize = sector_size;
1031 sc->xbd_disk->d_stripesize = phys_sector_size;
1032 sc->xbd_disk->d_stripeoffset = 0;
1033
1034 /*
1035 * The 'sectors' xenbus node is always in units of 512b, regardless of
1036 * the 'sector-size' xenbus node value.
1037 */
1038 sc->xbd_disk->d_mediasize = sectors << XBD_SECTOR_SHFT;
1039 if ((sc->xbd_disk->d_mediasize % sc->xbd_disk->d_sectorsize) != 0) {
1040 error = EINVAL;
1041 xenbus_dev_fatal(sc->xbd_dev, error,
1042 "Disk size (%ju) not a multiple of sector size (%ju)",
1043 (uintmax_t)sc->xbd_disk->d_mediasize,
1044 (uintmax_t)sc->xbd_disk->d_sectorsize);
1045 return (error);
1046 }
1047 sc->xbd_disk->d_maxsize = sc->xbd_max_request_size;
1048 sc->xbd_disk->d_flags = DISKFLAG_UNMAPPED_BIO;
1049 if ((sc->xbd_flags & (XBDF_FLUSH|XBDF_BARRIER)) != 0) {
1050 sc->xbd_disk->d_flags |= DISKFLAG_CANFLUSHCACHE;
1051 device_printf(sc->xbd_dev,
1052 "synchronize cache commands enabled.\n");
1053 }
1054 disk_create(sc->xbd_disk, DISK_VERSION);
1055
1056 return error;
1057 }
1058
1059 static void
xbd_free(struct xbd_softc * sc)1060 xbd_free(struct xbd_softc *sc)
1061 {
1062 int i;
1063
1064 /* Prevent new requests being issued until we fix things up. */
1065 mtx_lock(&sc->xbd_io_lock);
1066 sc->xbd_state = XBD_STATE_DISCONNECTED;
1067 mtx_unlock(&sc->xbd_io_lock);
1068
1069 /* Free resources associated with old device channel. */
1070 xbd_free_ring(sc);
1071 if (sc->xbd_shadow) {
1072 for (i = 0; i < sc->xbd_max_requests; i++) {
1073 struct xbd_command *cm;
1074
1075 cm = &sc->xbd_shadow[i];
1076 if (cm->cm_sg_refs != NULL) {
1077 free(cm->cm_sg_refs, M_XENBLOCKFRONT);
1078 cm->cm_sg_refs = NULL;
1079 }
1080
1081 if (cm->cm_indirectionpages != NULL) {
1082 gnttab_end_foreign_access_references(
1083 sc->xbd_max_request_indirectpages,
1084 &cm->cm_indirectionrefs[0]);
1085 contigfree(cm->cm_indirectionpages, PAGE_SIZE *
1086 sc->xbd_max_request_indirectpages,
1087 M_XENBLOCKFRONT);
1088 cm->cm_indirectionpages = NULL;
1089 }
1090
1091 bus_dmamap_destroy(sc->xbd_io_dmat, cm->cm_map);
1092 }
1093 free(sc->xbd_shadow, M_XENBLOCKFRONT);
1094 sc->xbd_shadow = NULL;
1095
1096 bus_dma_tag_destroy(sc->xbd_io_dmat);
1097
1098 xbd_initq_cm(sc, XBD_Q_FREE);
1099 xbd_initq_cm(sc, XBD_Q_READY);
1100 xbd_initq_cm(sc, XBD_Q_COMPLETE);
1101 }
1102
1103 xen_intr_unbind(&sc->xen_intr_handle);
1104
1105 }
1106
1107 /*--------------------------- State Change Handlers --------------------------*/
1108 static void
xbd_initialize(struct xbd_softc * sc)1109 xbd_initialize(struct xbd_softc *sc)
1110 {
1111 const char *otherend_path;
1112 const char *node_path;
1113 uint32_t max_ring_page_order;
1114 int error;
1115
1116 if (xenbus_get_state(sc->xbd_dev) != XenbusStateInitialising) {
1117 /* Initialization has already been performed. */
1118 return;
1119 }
1120
1121 /*
1122 * Protocol defaults valid even if negotiation for a
1123 * setting fails.
1124 */
1125 max_ring_page_order = 0;
1126 sc->xbd_ring_pages = 1;
1127
1128 /*
1129 * Protocol negotiation.
1130 *
1131 * \note xs_gather() returns on the first encountered error, so
1132 * we must use independent calls in order to guarantee
1133 * we don't miss information in a sparsly populated back-end
1134 * tree.
1135 *
1136 * \note xs_scanf() does not update variables for unmatched
1137 * fields.
1138 */
1139 otherend_path = xenbus_get_otherend_path(sc->xbd_dev);
1140 node_path = xenbus_get_node(sc->xbd_dev);
1141
1142 /* Support both backend schemes for relaying ring page limits. */
1143 (void)xs_scanf(XST_NIL, otherend_path,
1144 "max-ring-page-order", NULL, "%" PRIu32,
1145 &max_ring_page_order);
1146 sc->xbd_ring_pages = 1 << max_ring_page_order;
1147 (void)xs_scanf(XST_NIL, otherend_path,
1148 "max-ring-pages", NULL, "%" PRIu32,
1149 &sc->xbd_ring_pages);
1150 if (sc->xbd_ring_pages < 1)
1151 sc->xbd_ring_pages = 1;
1152
1153 if (sc->xbd_ring_pages > XBD_MAX_RING_PAGES) {
1154 device_printf(sc->xbd_dev,
1155 "Back-end specified ring-pages of %u "
1156 "limited to front-end limit of %u.\n",
1157 sc->xbd_ring_pages, XBD_MAX_RING_PAGES);
1158 sc->xbd_ring_pages = XBD_MAX_RING_PAGES;
1159 }
1160
1161 if (powerof2(sc->xbd_ring_pages) == 0) {
1162 uint32_t new_page_limit;
1163
1164 new_page_limit = 0x01 << (fls(sc->xbd_ring_pages) - 1);
1165 device_printf(sc->xbd_dev,
1166 "Back-end specified ring-pages of %u "
1167 "is not a power of 2. Limited to %u.\n",
1168 sc->xbd_ring_pages, new_page_limit);
1169 sc->xbd_ring_pages = new_page_limit;
1170 }
1171
1172 sc->xbd_max_requests =
1173 BLKIF_MAX_RING_REQUESTS(sc->xbd_ring_pages * PAGE_SIZE);
1174 if (sc->xbd_max_requests > XBD_MAX_REQUESTS) {
1175 device_printf(sc->xbd_dev,
1176 "Back-end specified max_requests of %u "
1177 "limited to front-end limit of %zu.\n",
1178 sc->xbd_max_requests, XBD_MAX_REQUESTS);
1179 sc->xbd_max_requests = XBD_MAX_REQUESTS;
1180 }
1181
1182 if (xbd_alloc_ring(sc) != 0)
1183 return;
1184
1185 /* Support both backend schemes for relaying ring page limits. */
1186 if (sc->xbd_ring_pages > 1) {
1187 error = xs_printf(XST_NIL, node_path,
1188 "num-ring-pages","%u",
1189 sc->xbd_ring_pages);
1190 if (error) {
1191 xenbus_dev_fatal(sc->xbd_dev, error,
1192 "writing %s/num-ring-pages",
1193 node_path);
1194 return;
1195 }
1196
1197 error = xs_printf(XST_NIL, node_path,
1198 "ring-page-order", "%u",
1199 fls(sc->xbd_ring_pages) - 1);
1200 if (error) {
1201 xenbus_dev_fatal(sc->xbd_dev, error,
1202 "writing %s/ring-page-order",
1203 node_path);
1204 return;
1205 }
1206 }
1207
1208 error = xs_printf(XST_NIL, node_path, "event-channel",
1209 "%u", xen_intr_port(sc->xen_intr_handle));
1210 if (error) {
1211 xenbus_dev_fatal(sc->xbd_dev, error,
1212 "writing %s/event-channel",
1213 node_path);
1214 return;
1215 }
1216
1217 error = xs_printf(XST_NIL, node_path, "protocol",
1218 "%s", XEN_IO_PROTO_ABI_NATIVE);
1219 if (error) {
1220 xenbus_dev_fatal(sc->xbd_dev, error,
1221 "writing %s/protocol",
1222 node_path);
1223 return;
1224 }
1225
1226 xenbus_set_state(sc->xbd_dev, XenbusStateInitialised);
1227 }
1228
1229 /*
1230 * Invoked when the backend is finally 'ready' (and has published
1231 * the details about the physical device - #sectors, size, etc).
1232 */
1233 static void
xbd_connect(struct xbd_softc * sc)1234 xbd_connect(struct xbd_softc *sc)
1235 {
1236 device_t dev = sc->xbd_dev;
1237 blkif_sector_t sectors;
1238 unsigned long sector_size, phys_sector_size;
1239 unsigned int binfo;
1240 int err, feature_barrier, feature_flush;
1241 int i, j;
1242
1243 DPRINTK("blkfront.c:connect:%s.\n", xenbus_get_otherend_path(dev));
1244
1245 if (sc->xbd_state == XBD_STATE_SUSPENDED) {
1246 return;
1247 }
1248
1249 if (sc->xbd_state == XBD_STATE_CONNECTED) {
1250 struct disk *disk;
1251
1252 disk = sc->xbd_disk;
1253 if (disk == NULL) {
1254 return;
1255 }
1256 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1257 "sectors", "%"PRIu64, §ors, NULL);
1258 if (err != 0) {
1259 xenbus_dev_error(dev, err,
1260 "reading sectors at %s",
1261 xenbus_get_otherend_path(dev));
1262 return;
1263 }
1264 disk->d_mediasize = disk->d_sectorsize * sectors;
1265 err = disk_resize(disk, M_NOWAIT);
1266 if (err) {
1267 xenbus_dev_error(dev, err,
1268 "unable to resize disk %s%u",
1269 disk->d_name, disk->d_unit);
1270 return;
1271 }
1272 device_printf(sc->xbd_dev,
1273 "changed capacity to %jd\n",
1274 (intmax_t)disk->d_mediasize);
1275 return;
1276 }
1277
1278 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1279 "sectors", "%"PRIu64, §ors,
1280 "info", "%u", &binfo,
1281 "sector-size", "%lu", §or_size,
1282 NULL);
1283 if (err) {
1284 xenbus_dev_fatal(dev, err,
1285 "reading backend fields at %s",
1286 xenbus_get_otherend_path(dev));
1287 return;
1288 }
1289 if ((sectors == 0) || (sector_size == 0)) {
1290 xenbus_dev_fatal(dev, 0,
1291 "invalid parameters from %s:"
1292 " sectors = %"PRIu64", sector_size = %lu",
1293 xenbus_get_otherend_path(dev),
1294 sectors, sector_size);
1295 return;
1296 }
1297 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1298 "physical-sector-size", "%lu", &phys_sector_size,
1299 NULL);
1300 if (err || phys_sector_size <= sector_size)
1301 phys_sector_size = 0;
1302 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1303 "feature-barrier", "%d", &feature_barrier,
1304 NULL);
1305 if (err == 0 && feature_barrier != 0)
1306 sc->xbd_flags |= XBDF_BARRIER;
1307
1308 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1309 "feature-flush-cache", "%d", &feature_flush,
1310 NULL);
1311 if (err == 0 && feature_flush != 0)
1312 sc->xbd_flags |= XBDF_FLUSH;
1313
1314 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1315 "feature-max-indirect-segments", "%" PRIu32,
1316 &sc->xbd_max_request_segments, NULL);
1317 if ((err != 0) || (xbd_enable_indirect == 0))
1318 sc->xbd_max_request_segments = 0;
1319 if (sc->xbd_max_request_segments > XBD_MAX_INDIRECT_SEGMENTS)
1320 sc->xbd_max_request_segments = XBD_MAX_INDIRECT_SEGMENTS;
1321 if (sc->xbd_max_request_segments > XBD_SIZE_TO_SEGS(maxphys))
1322 sc->xbd_max_request_segments = XBD_SIZE_TO_SEGS(maxphys);
1323 sc->xbd_max_request_indirectpages =
1324 XBD_INDIRECT_SEGS_TO_PAGES(sc->xbd_max_request_segments);
1325 if (sc->xbd_max_request_segments < BLKIF_MAX_SEGMENTS_PER_REQUEST)
1326 sc->xbd_max_request_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST;
1327 sc->xbd_max_request_size =
1328 XBD_SEGS_TO_SIZE(sc->xbd_max_request_segments);
1329
1330 /* Allocate datastructures based on negotiated values. */
1331 err = bus_dma_tag_create(
1332 bus_get_dma_tag(sc->xbd_dev), /* parent */
1333 sector_size, PAGE_SIZE, /* algnmnt, boundary */
1334 BUS_SPACE_MAXADDR, /* lowaddr */
1335 BUS_SPACE_MAXADDR, /* highaddr */
1336 NULL, NULL, /* filter, filterarg */
1337 sc->xbd_max_request_size,
1338 sc->xbd_max_request_segments,
1339 PAGE_SIZE, /* maxsegsize */
1340 BUS_DMA_ALLOCNOW, /* flags */
1341 busdma_lock_mutex, /* lockfunc */
1342 &sc->xbd_io_lock, /* lockarg */
1343 &sc->xbd_io_dmat);
1344 if (err != 0) {
1345 xenbus_dev_fatal(sc->xbd_dev, err,
1346 "Cannot allocate parent DMA tag\n");
1347 return;
1348 }
1349
1350 /* Per-transaction data allocation. */
1351 sc->xbd_shadow = malloc(sizeof(*sc->xbd_shadow) * sc->xbd_max_requests,
1352 M_XENBLOCKFRONT, M_NOWAIT|M_ZERO);
1353 if (sc->xbd_shadow == NULL) {
1354 bus_dma_tag_destroy(sc->xbd_io_dmat);
1355 xenbus_dev_fatal(sc->xbd_dev, ENOMEM,
1356 "Cannot allocate request structures\n");
1357 return;
1358 }
1359
1360 for (i = 0; i < sc->xbd_max_requests; i++) {
1361 struct xbd_command *cm;
1362 void * indirectpages;
1363
1364 cm = &sc->xbd_shadow[i];
1365 cm->cm_sg_refs = malloc(
1366 sizeof(grant_ref_t) * sc->xbd_max_request_segments,
1367 M_XENBLOCKFRONT, M_NOWAIT);
1368 if (cm->cm_sg_refs == NULL)
1369 break;
1370 cm->cm_id = i;
1371 cm->cm_flags = XBDCF_INITIALIZER;
1372 cm->cm_sc = sc;
1373 if (bus_dmamap_create(sc->xbd_io_dmat, 0, &cm->cm_map) != 0)
1374 break;
1375 if (sc->xbd_max_request_indirectpages > 0) {
1376 indirectpages = contigmalloc(
1377 PAGE_SIZE * sc->xbd_max_request_indirectpages,
1378 M_XENBLOCKFRONT, M_ZERO | M_NOWAIT, 0, ~0,
1379 PAGE_SIZE, 0);
1380 if (indirectpages == NULL)
1381 sc->xbd_max_request_indirectpages = 0;
1382 } else {
1383 indirectpages = NULL;
1384 }
1385 for (j = 0; j < sc->xbd_max_request_indirectpages; j++) {
1386 if (gnttab_grant_foreign_access(
1387 xenbus_get_otherend_id(sc->xbd_dev),
1388 (vtophys(indirectpages) >> PAGE_SHIFT) + j,
1389 1 /* grant read-only access */,
1390 &cm->cm_indirectionrefs[j]))
1391 break;
1392 }
1393 if (j < sc->xbd_max_request_indirectpages) {
1394 contigfree(indirectpages,
1395 PAGE_SIZE * sc->xbd_max_request_indirectpages,
1396 M_XENBLOCKFRONT);
1397 break;
1398 }
1399 cm->cm_indirectionpages = indirectpages;
1400 xbd_free_command(cm);
1401 }
1402
1403 if (sc->xbd_disk == NULL) {
1404 device_printf(dev, "%juMB <%s> at %s",
1405 (uintmax_t)((sectors << XBD_SECTOR_SHFT) / 1048576),
1406 device_get_desc(dev),
1407 xenbus_get_node(dev));
1408 bus_print_child_footer(device_get_parent(dev), dev);
1409
1410 err = xbd_instance_create(sc, sectors, sc->xbd_vdevice, binfo,
1411 sector_size, phys_sector_size);
1412 if (err != 0) {
1413 xenbus_dev_fatal(dev, err, "Unable to create instance");
1414 return;
1415 }
1416 }
1417
1418 (void)xenbus_set_state(dev, XenbusStateConnected);
1419
1420 /* Kick pending requests. */
1421 mtx_lock(&sc->xbd_io_lock);
1422 sc->xbd_state = XBD_STATE_CONNECTED;
1423 xbd_startio(sc);
1424 sc->xbd_flags |= XBDF_READY;
1425 mtx_unlock(&sc->xbd_io_lock);
1426 }
1427
1428 /**
1429 * Handle the change of state of the backend to Closing. We must delete our
1430 * device-layer structures now, to ensure that writes are flushed through to
1431 * the backend. Once this is done, we can switch to Closed in
1432 * acknowledgement.
1433 */
1434 static void
xbd_closing(device_t dev)1435 xbd_closing(device_t dev)
1436 {
1437 struct xbd_softc *sc = device_get_softc(dev);
1438
1439 xenbus_set_state(dev, XenbusStateClosing);
1440
1441 DPRINTK("xbd_closing: %s removed\n", xenbus_get_node(dev));
1442
1443 if (sc->xbd_disk != NULL) {
1444 disk_destroy(sc->xbd_disk);
1445 sc->xbd_disk = NULL;
1446 }
1447
1448 xenbus_set_state(dev, XenbusStateClosed);
1449 }
1450
1451 /*---------------------------- NewBus Entrypoints ----------------------------*/
1452 static int
xbd_probe(device_t dev)1453 xbd_probe(device_t dev)
1454 {
1455 if (strcmp(xenbus_get_type(dev), "vbd") != 0)
1456 return (ENXIO);
1457
1458 if (xen_pv_disks_disabled())
1459 return (ENXIO);
1460
1461 if (xen_hvm_domain()) {
1462 int error;
1463 char *type;
1464
1465 /*
1466 * When running in an HVM domain, IDE disk emulation is
1467 * disabled early in boot so that native drivers will
1468 * not see emulated hardware. However, CDROM device
1469 * emulation cannot be disabled.
1470 *
1471 * Through use of FreeBSD's vm_guest and xen_hvm_domain()
1472 * APIs, we could modify the native CDROM driver to fail its
1473 * probe when running under Xen. Unfortunatlely, the PV
1474 * CDROM support in XenServer (up through at least version
1475 * 6.2) isn't functional, so we instead rely on the emulated
1476 * CDROM instance, and fail to attach the PV one here in
1477 * the blkfront driver.
1478 */
1479 error = xs_read(XST_NIL, xenbus_get_node(dev),
1480 "device-type", NULL, (void **) &type);
1481 if (error)
1482 return (ENXIO);
1483
1484 if (strncmp(type, "cdrom", 5) == 0) {
1485 free(type, M_XENSTORE);
1486 return (ENXIO);
1487 }
1488 free(type, M_XENSTORE);
1489 }
1490
1491 device_set_desc(dev, "Virtual Block Device");
1492 device_quiet(dev);
1493 return (0);
1494 }
1495
1496 /*
1497 * Setup supplies the backend dir, virtual device. We place an event
1498 * channel and shared frame entries. We watch backend to wait if it's
1499 * ok.
1500 */
1501 static int
xbd_attach(device_t dev)1502 xbd_attach(device_t dev)
1503 {
1504 struct xbd_softc *sc;
1505 const char *name;
1506 uint32_t vdevice;
1507 int error;
1508 int i;
1509 int unit;
1510
1511 /* FIXME: Use dynamic device id if this is not set. */
1512 error = xs_scanf(XST_NIL, xenbus_get_node(dev),
1513 "virtual-device", NULL, "%" PRIu32, &vdevice);
1514 if (error)
1515 error = xs_scanf(XST_NIL, xenbus_get_node(dev),
1516 "virtual-device-ext", NULL, "%" PRIu32, &vdevice);
1517 if (error) {
1518 xenbus_dev_fatal(dev, error, "reading virtual-device");
1519 device_printf(dev, "Couldn't determine virtual device.\n");
1520 return (error);
1521 }
1522
1523 xbd_vdevice_to_unit(vdevice, &unit, &name);
1524 if (!strcmp(name, "xbd"))
1525 device_set_unit(dev, unit);
1526
1527 sc = device_get_softc(dev);
1528 mtx_init(&sc->xbd_io_lock, "blkfront i/o lock", NULL, MTX_DEF);
1529 xbd_initqs(sc);
1530 for (i = 0; i < XBD_MAX_RING_PAGES; i++)
1531 sc->xbd_ring_ref[i] = GRANT_REF_INVALID;
1532
1533 sc->xbd_dev = dev;
1534 sc->xbd_vdevice = vdevice;
1535 sc->xbd_state = XBD_STATE_DISCONNECTED;
1536
1537 xbd_setup_sysctl(sc);
1538
1539 /* Wait for backend device to publish its protocol capabilities. */
1540 xenbus_set_state(dev, XenbusStateInitialising);
1541
1542 return (0);
1543 }
1544
1545 static int
xbd_detach(device_t dev)1546 xbd_detach(device_t dev)
1547 {
1548 struct xbd_softc *sc = device_get_softc(dev);
1549
1550 DPRINTK("%s: %s removed\n", __func__, xenbus_get_node(dev));
1551
1552 xbd_free(sc);
1553 mtx_destroy(&sc->xbd_io_lock);
1554
1555 return 0;
1556 }
1557
1558 static int
xbd_suspend(device_t dev)1559 xbd_suspend(device_t dev)
1560 {
1561 struct xbd_softc *sc = device_get_softc(dev);
1562 int retval;
1563 int saved_state;
1564
1565 /* Prevent new requests being issued until we fix things up. */
1566 mtx_lock(&sc->xbd_io_lock);
1567 saved_state = sc->xbd_state;
1568 sc->xbd_state = XBD_STATE_SUSPENDED;
1569
1570 /* Wait for outstanding I/O to drain. */
1571 retval = 0;
1572 while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
1573 if (msleep(&sc->xbd_cm_q[XBD_Q_BUSY], &sc->xbd_io_lock,
1574 PRIBIO, "blkf_susp", 30 * hz) == EWOULDBLOCK) {
1575 retval = EBUSY;
1576 break;
1577 }
1578 }
1579 mtx_unlock(&sc->xbd_io_lock);
1580
1581 if (retval != 0)
1582 sc->xbd_state = saved_state;
1583
1584 return (retval);
1585 }
1586
1587 static int
xbd_resume(device_t dev)1588 xbd_resume(device_t dev)
1589 {
1590 struct xbd_softc *sc = device_get_softc(dev);
1591
1592 if (xen_suspend_cancelled) {
1593 sc->xbd_state = XBD_STATE_CONNECTED;
1594 return (0);
1595 }
1596
1597 DPRINTK("xbd_resume: %s\n", xenbus_get_node(dev));
1598
1599 xbd_free(sc);
1600 xbd_initialize(sc);
1601 return (0);
1602 }
1603
1604 /**
1605 * Callback received when the backend's state changes.
1606 */
1607 static void
xbd_backend_changed(device_t dev,XenbusState backend_state)1608 xbd_backend_changed(device_t dev, XenbusState backend_state)
1609 {
1610 struct xbd_softc *sc = device_get_softc(dev);
1611
1612 DPRINTK("backend_state=%d\n", backend_state);
1613
1614 switch (backend_state) {
1615 case XenbusStateUnknown:
1616 case XenbusStateInitialising:
1617 case XenbusStateReconfigured:
1618 case XenbusStateReconfiguring:
1619 case XenbusStateClosed:
1620 break;
1621
1622 case XenbusStateInitWait:
1623 case XenbusStateInitialised:
1624 xbd_initialize(sc);
1625 break;
1626
1627 case XenbusStateConnected:
1628 xbd_initialize(sc);
1629 xbd_connect(sc);
1630 break;
1631
1632 case XenbusStateClosing:
1633 if (sc->xbd_users > 0) {
1634 device_printf(dev, "detaching with pending users\n");
1635 KASSERT(sc->xbd_disk != NULL,
1636 ("NULL disk with pending users\n"));
1637 disk_gone(sc->xbd_disk);
1638 } else {
1639 xbd_closing(dev);
1640 }
1641 break;
1642 }
1643 }
1644
1645 /*---------------------------- NewBus Registration ---------------------------*/
1646 static device_method_t xbd_methods[] = {
1647 /* Device interface */
1648 DEVMETHOD(device_probe, xbd_probe),
1649 DEVMETHOD(device_attach, xbd_attach),
1650 DEVMETHOD(device_detach, xbd_detach),
1651 DEVMETHOD(device_shutdown, bus_generic_shutdown),
1652 DEVMETHOD(device_suspend, xbd_suspend),
1653 DEVMETHOD(device_resume, xbd_resume),
1654
1655 /* Xenbus interface */
1656 DEVMETHOD(xenbus_otherend_changed, xbd_backend_changed),
1657
1658 { 0, 0 }
1659 };
1660
1661 static driver_t xbd_driver = {
1662 "xbd",
1663 xbd_methods,
1664 sizeof(struct xbd_softc),
1665 };
1666
1667 DRIVER_MODULE(xbd, xenbusb_front, xbd_driver, 0, 0);
1668