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