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 __FBSDID("$FreeBSD$");
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/malloc.h>
37 #include <sys/kernel.h>
38 #include <vm/vm.h>
39 #include <vm/pmap.h>
40
41 #include <sys/bio.h>
42 #include <sys/bus.h>
43 #include <sys/conf.h>
44 #include <sys/module.h>
45 #include <sys/sysctl.h>
46
47 #include <machine/bus.h>
48 #include <sys/rman.h>
49 #include <machine/resource.h>
50 #include <machine/intr_machdep.h>
51 #include <machine/vmparam.h>
52
53 #include <xen/xen-os.h>
54 #include <xen/hypervisor.h>
55 #include <xen/xen_intr.h>
56 #include <xen/gnttab.h>
57 #include <xen/interface/grant_table.h>
58 #include <xen/interface/io/protocols.h>
59 #include <xen/xenbus/xenbusvar.h>
60
61 #include <machine/_inttypes.h>
62
63 #include <geom/geom_disk.h>
64
65 #include <dev/xen/blkfront/block.h>
66
67 #include "xenbus_if.h"
68
69 /*--------------------------- Forward Declarations ---------------------------*/
70 static void xbd_closing(device_t);
71 static void xbd_startio(struct xbd_softc *sc);
72
73 /*---------------------------------- Macros ----------------------------------*/
74 #if 0
75 #define DPRINTK(fmt, args...) printf("[XEN] %s:%d: " fmt ".\n", __func__, __LINE__, ##args)
76 #else
77 #define DPRINTK(fmt, args...)
78 #endif
79
80 #define XBD_SECTOR_SHFT 9
81
82 /*---------------------------- Global Static Data ----------------------------*/
83 static MALLOC_DEFINE(M_XENBLOCKFRONT, "xbd", "Xen Block Front driver data");
84
85 static int xbd_enable_indirect = 1;
86 SYSCTL_NODE(_hw, OID_AUTO, xbd, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
87 "xbd driver parameters");
88 SYSCTL_INT(_hw_xbd, OID_AUTO, xbd_enable_indirect, CTLFLAG_RDTUN,
89 &xbd_enable_indirect, 0, "Enable xbd indirect segments");
90
91 /*---------------------------- Command Processing ----------------------------*/
92 static void
xbd_freeze(struct xbd_softc * sc,xbd_flag_t xbd_flag)93 xbd_freeze(struct xbd_softc *sc, xbd_flag_t xbd_flag)
94 {
95 if (xbd_flag != XBDF_NONE && (sc->xbd_flags & xbd_flag) != 0)
96 return;
97
98 sc->xbd_flags |= xbd_flag;
99 sc->xbd_qfrozen_cnt++;
100 }
101
102 static void
xbd_thaw(struct xbd_softc * sc,xbd_flag_t xbd_flag)103 xbd_thaw(struct xbd_softc *sc, xbd_flag_t xbd_flag)
104 {
105 if (xbd_flag != XBDF_NONE && (sc->xbd_flags & xbd_flag) == 0)
106 return;
107
108 if (sc->xbd_qfrozen_cnt == 0)
109 panic("%s: Thaw with flag 0x%x while not frozen.",
110 __func__, xbd_flag);
111
112 sc->xbd_flags &= ~xbd_flag;
113 sc->xbd_qfrozen_cnt--;
114 }
115
116 static void
xbd_cm_freeze(struct xbd_softc * sc,struct xbd_command * cm,xbdc_flag_t cm_flag)117 xbd_cm_freeze(struct xbd_softc *sc, struct xbd_command *cm, xbdc_flag_t cm_flag)
118 {
119 if ((cm->cm_flags & XBDCF_FROZEN) != 0)
120 return;
121
122 cm->cm_flags |= XBDCF_FROZEN|cm_flag;
123 xbd_freeze(sc, XBDF_NONE);
124 }
125
126 static void
xbd_cm_thaw(struct xbd_softc * sc,struct xbd_command * cm)127 xbd_cm_thaw(struct xbd_softc *sc, struct xbd_command *cm)
128 {
129 if ((cm->cm_flags & XBDCF_FROZEN) == 0)
130 return;
131
132 cm->cm_flags &= ~XBDCF_FROZEN;
133 xbd_thaw(sc, XBDF_NONE);
134 }
135
136 static inline void
xbd_flush_requests(struct xbd_softc * sc)137 xbd_flush_requests(struct xbd_softc *sc)
138 {
139 int notify;
140
141 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&sc->xbd_ring, notify);
142
143 if (notify)
144 xen_intr_signal(sc->xen_intr_handle);
145 }
146
147 static void
xbd_free_command(struct xbd_command * cm)148 xbd_free_command(struct xbd_command *cm)
149 {
150
151 KASSERT((cm->cm_flags & XBDCF_Q_MASK) == XBD_Q_NONE,
152 ("Freeing command that is still on queue %d.",
153 cm->cm_flags & XBDCF_Q_MASK));
154
155 cm->cm_flags = XBDCF_INITIALIZER;
156 cm->cm_bp = NULL;
157 cm->cm_complete = NULL;
158 xbd_enqueue_cm(cm, XBD_Q_FREE);
159 xbd_thaw(cm->cm_sc, XBDF_CM_SHORTAGE);
160 }
161
162 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)163 xbd_mksegarray(bus_dma_segment_t *segs, int nsegs,
164 grant_ref_t * gref_head, int otherend_id, int readonly,
165 grant_ref_t * sg_ref, struct blkif_request_segment *sg)
166 {
167 struct blkif_request_segment *last_block_sg = sg + nsegs;
168 vm_paddr_t buffer_ma;
169 uint64_t fsect, lsect;
170 int ref;
171
172 while (sg < last_block_sg) {
173 KASSERT(segs->ds_addr % (1 << XBD_SECTOR_SHFT) == 0,
174 ("XEN disk driver I/O must be sector aligned"));
175 KASSERT(segs->ds_len % (1 << XBD_SECTOR_SHFT) == 0,
176 ("XEN disk driver I/Os must be a multiple of "
177 "the sector length"));
178 buffer_ma = segs->ds_addr;
179 fsect = (buffer_ma & PAGE_MASK) >> XBD_SECTOR_SHFT;
180 lsect = fsect + (segs->ds_len >> XBD_SECTOR_SHFT) - 1;
181
182 KASSERT(lsect <= 7, ("XEN disk driver data cannot "
183 "cross a page boundary"));
184
185 /* install a grant reference. */
186 ref = gnttab_claim_grant_reference(gref_head);
187
188 /*
189 * GNTTAB_LIST_END == 0xffffffff, but it is private
190 * to gnttab.c.
191 */
192 KASSERT(ref != ~0, ("grant_reference failed"));
193
194 gnttab_grant_foreign_access_ref(
195 ref,
196 otherend_id,
197 buffer_ma >> PAGE_SHIFT,
198 readonly);
199
200 *sg_ref = ref;
201 *sg = (struct blkif_request_segment) {
202 .gref = ref,
203 .first_sect = fsect,
204 .last_sect = lsect
205 };
206 sg++;
207 sg_ref++;
208 segs++;
209 }
210 }
211
212 static void
xbd_queue_cb(void * arg,bus_dma_segment_t * segs,int nsegs,int error)213 xbd_queue_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
214 {
215 struct xbd_softc *sc;
216 struct xbd_command *cm;
217 int op;
218
219 cm = arg;
220 sc = cm->cm_sc;
221
222 if (error) {
223 cm->cm_bp->bio_error = EIO;
224 biodone(cm->cm_bp);
225 xbd_free_command(cm);
226 return;
227 }
228
229 KASSERT(nsegs <= sc->xbd_max_request_segments,
230 ("Too many segments in a blkfront I/O"));
231
232 if (nsegs <= BLKIF_MAX_SEGMENTS_PER_REQUEST) {
233 blkif_request_t *ring_req;
234
235 /* Fill out a blkif_request_t structure. */
236 ring_req = (blkif_request_t *)
237 RING_GET_REQUEST(&sc->xbd_ring, sc->xbd_ring.req_prod_pvt);
238 sc->xbd_ring.req_prod_pvt++;
239 ring_req->id = cm->cm_id;
240 ring_req->operation = cm->cm_operation;
241 ring_req->sector_number = cm->cm_sector_number;
242 ring_req->handle = (blkif_vdev_t)(uintptr_t)sc->xbd_disk;
243 ring_req->nr_segments = nsegs;
244 cm->cm_nseg = nsegs;
245 xbd_mksegarray(segs, nsegs, &cm->cm_gref_head,
246 xenbus_get_otherend_id(sc->xbd_dev),
247 cm->cm_operation == BLKIF_OP_WRITE,
248 cm->cm_sg_refs, ring_req->seg);
249 } else {
250 blkif_request_indirect_t *ring_req;
251
252 /* Fill out a blkif_request_indirect_t structure. */
253 ring_req = (blkif_request_indirect_t *)
254 RING_GET_REQUEST(&sc->xbd_ring, sc->xbd_ring.req_prod_pvt);
255 sc->xbd_ring.req_prod_pvt++;
256 ring_req->id = cm->cm_id;
257 ring_req->operation = BLKIF_OP_INDIRECT;
258 ring_req->indirect_op = cm->cm_operation;
259 ring_req->sector_number = cm->cm_sector_number;
260 ring_req->handle = (blkif_vdev_t)(uintptr_t)sc->xbd_disk;
261 ring_req->nr_segments = nsegs;
262 cm->cm_nseg = nsegs;
263 xbd_mksegarray(segs, nsegs, &cm->cm_gref_head,
264 xenbus_get_otherend_id(sc->xbd_dev),
265 cm->cm_operation == BLKIF_OP_WRITE,
266 cm->cm_sg_refs, cm->cm_indirectionpages);
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 = (blkif_sector_t)bp->bio_pblkno;
367
368 switch (bp->bio_cmd) {
369 case BIO_READ:
370 cm->cm_operation = BLKIF_OP_READ;
371 break;
372 case BIO_WRITE:
373 cm->cm_operation = BLKIF_OP_WRITE;
374 if ((bp->bio_flags & BIO_ORDERED) != 0) {
375 if ((sc->xbd_flags & XBDF_BARRIER) != 0) {
376 cm->cm_operation = BLKIF_OP_WRITE_BARRIER;
377 } else {
378 /*
379 * Single step this command.
380 */
381 cm->cm_flags |= XBDCF_Q_FREEZE;
382 if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
383 /*
384 * Wait for in-flight requests to
385 * finish.
386 */
387 xbd_freeze(sc, XBDF_WAIT_IDLE);
388 xbd_requeue_cm(cm, XBD_Q_READY);
389 return (NULL);
390 }
391 }
392 }
393 break;
394 case BIO_FLUSH:
395 if ((sc->xbd_flags & XBDF_FLUSH) != 0)
396 cm->cm_operation = BLKIF_OP_FLUSH_DISKCACHE;
397 else if ((sc->xbd_flags & XBDF_BARRIER) != 0)
398 cm->cm_operation = BLKIF_OP_WRITE_BARRIER;
399 else
400 panic("flush request, but no flush support available");
401 break;
402 default:
403 biofinish(bp, NULL, EOPNOTSUPP);
404 xbd_enqueue_cm(cm, XBD_Q_FREE);
405 return (NULL);
406 }
407
408 return (cm);
409 }
410
411 /*
412 * Dequeue buffers and place them in the shared communication ring.
413 * Return when no more requests can be accepted or all buffers have
414 * been queued.
415 *
416 * Signal XEN once the ring has been filled out.
417 */
418 static void
xbd_startio(struct xbd_softc * sc)419 xbd_startio(struct xbd_softc *sc)
420 {
421 struct xbd_command *cm;
422 int error, queued = 0;
423
424 mtx_assert(&sc->xbd_io_lock, MA_OWNED);
425
426 if (sc->xbd_state != XBD_STATE_CONNECTED)
427 return;
428
429 while (!RING_FULL(&sc->xbd_ring)) {
430 if (sc->xbd_qfrozen_cnt != 0)
431 break;
432
433 cm = xbd_dequeue_cm(sc, XBD_Q_READY);
434
435 if (cm == NULL)
436 cm = xbd_bio_command(sc);
437
438 if (cm == NULL)
439 break;
440
441 if ((cm->cm_flags & XBDCF_Q_FREEZE) != 0) {
442 /*
443 * Single step command. Future work is
444 * held off until this command completes.
445 */
446 xbd_cm_freeze(sc, cm, XBDCF_Q_FREEZE);
447 }
448
449 if ((error = xbd_queue_request(sc, cm)) != 0) {
450 printf("xbd_queue_request returned %d\n", error);
451 break;
452 }
453 queued++;
454 }
455
456 if (queued != 0)
457 xbd_flush_requests(sc);
458 }
459
460 static void
xbd_bio_complete(struct xbd_softc * sc,struct xbd_command * cm)461 xbd_bio_complete(struct xbd_softc *sc, struct xbd_command *cm)
462 {
463 struct bio *bp;
464
465 bp = cm->cm_bp;
466
467 if (__predict_false(cm->cm_status != BLKIF_RSP_OKAY)) {
468 disk_err(bp, "disk error" , -1, 0);
469 printf(" status: %x\n", cm->cm_status);
470 bp->bio_flags |= BIO_ERROR;
471 }
472
473 if (bp->bio_flags & BIO_ERROR)
474 bp->bio_error = EIO;
475 else
476 bp->bio_resid = 0;
477
478 xbd_free_command(cm);
479 biodone(bp);
480 }
481
482 static void
xbd_int(void * xsc)483 xbd_int(void *xsc)
484 {
485 struct xbd_softc *sc = xsc;
486 struct xbd_command *cm;
487 blkif_response_t *bret;
488 RING_IDX i, rp;
489 int op;
490
491 mtx_lock(&sc->xbd_io_lock);
492
493 if (__predict_false(sc->xbd_state == XBD_STATE_DISCONNECTED)) {
494 mtx_unlock(&sc->xbd_io_lock);
495 return;
496 }
497
498 again:
499 rp = sc->xbd_ring.sring->rsp_prod;
500 rmb(); /* Ensure we see queued responses up to 'rp'. */
501
502 for (i = sc->xbd_ring.rsp_cons; i != rp;) {
503 bret = RING_GET_RESPONSE(&sc->xbd_ring, i);
504 cm = &sc->xbd_shadow[bret->id];
505
506 xbd_remove_cm(cm, XBD_Q_BUSY);
507 gnttab_end_foreign_access_references(cm->cm_nseg,
508 cm->cm_sg_refs);
509 i++;
510
511 if (cm->cm_operation == BLKIF_OP_READ)
512 op = BUS_DMASYNC_POSTREAD;
513 else if (cm->cm_operation == BLKIF_OP_WRITE ||
514 cm->cm_operation == BLKIF_OP_WRITE_BARRIER)
515 op = BUS_DMASYNC_POSTWRITE;
516 else
517 op = 0;
518 bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op);
519 bus_dmamap_unload(sc->xbd_io_dmat, cm->cm_map);
520
521 /*
522 * Release any hold this command has on future command
523 * dispatch.
524 */
525 xbd_cm_thaw(sc, cm);
526
527 /*
528 * Directly call the i/o complete routine to save an
529 * an indirection in the common case.
530 */
531 cm->cm_status = bret->status;
532 if (cm->cm_bp)
533 xbd_bio_complete(sc, cm);
534 else if (cm->cm_complete != NULL)
535 cm->cm_complete(cm);
536 else
537 xbd_free_command(cm);
538 }
539
540 sc->xbd_ring.rsp_cons = i;
541
542 if (i != sc->xbd_ring.req_prod_pvt) {
543 int more_to_do;
544 RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, more_to_do);
545 if (more_to_do)
546 goto again;
547 } else {
548 sc->xbd_ring.sring->rsp_event = i + 1;
549 }
550
551 if (xbd_queue_length(sc, XBD_Q_BUSY) == 0)
552 xbd_thaw(sc, XBDF_WAIT_IDLE);
553
554 xbd_startio(sc);
555
556 if (__predict_false(sc->xbd_state == XBD_STATE_SUSPENDED))
557 wakeup(&sc->xbd_cm_q[XBD_Q_BUSY]);
558
559 mtx_unlock(&sc->xbd_io_lock);
560 }
561
562 /*------------------------------- Dump Support -------------------------------*/
563 /**
564 * Quiesce the disk writes for a dump file before allowing the next buffer.
565 */
566 static void
xbd_quiesce(struct xbd_softc * sc)567 xbd_quiesce(struct xbd_softc *sc)
568 {
569 int mtd;
570
571 // While there are outstanding requests
572 while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
573 RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, mtd);
574 if (mtd) {
575 /* Received request completions, update queue. */
576 xbd_int(sc);
577 }
578 if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
579 /*
580 * Still pending requests, wait for the disk i/o
581 * to complete.
582 */
583 HYPERVISOR_yield();
584 }
585 }
586 }
587
588 /* Kernel dump function for a paravirtualized disk device */
589 static void
xbd_dump_complete(struct xbd_command * cm)590 xbd_dump_complete(struct xbd_command *cm)
591 {
592
593 xbd_enqueue_cm(cm, XBD_Q_COMPLETE);
594 }
595
596 static int
xbd_dump(void * arg,void * virtual,vm_offset_t physical,off_t offset,size_t length)597 xbd_dump(void *arg, void *virtual, vm_offset_t physical, off_t offset,
598 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 sbp;
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 for (sbp=0; length > 0; sbp++) {
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 / dp->d_sectorsize;
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 sc->xbd_disk->d_mediasize = sectors * sector_size;
1035 sc->xbd_disk->d_maxsize = sc->xbd_max_request_size;
1036 sc->xbd_disk->d_flags = DISKFLAG_UNMAPPED_BIO;
1037 if ((sc->xbd_flags & (XBDF_FLUSH|XBDF_BARRIER)) != 0) {
1038 sc->xbd_disk->d_flags |= DISKFLAG_CANFLUSHCACHE;
1039 device_printf(sc->xbd_dev,
1040 "synchronize cache commands enabled.\n");
1041 }
1042 disk_create(sc->xbd_disk, DISK_VERSION);
1043
1044 return error;
1045 }
1046
1047 static void
xbd_free(struct xbd_softc * sc)1048 xbd_free(struct xbd_softc *sc)
1049 {
1050 int i;
1051
1052 /* Prevent new requests being issued until we fix things up. */
1053 mtx_lock(&sc->xbd_io_lock);
1054 sc->xbd_state = XBD_STATE_DISCONNECTED;
1055 mtx_unlock(&sc->xbd_io_lock);
1056
1057 /* Free resources associated with old device channel. */
1058 xbd_free_ring(sc);
1059 if (sc->xbd_shadow) {
1060 for (i = 0; i < sc->xbd_max_requests; i++) {
1061 struct xbd_command *cm;
1062
1063 cm = &sc->xbd_shadow[i];
1064 if (cm->cm_sg_refs != NULL) {
1065 free(cm->cm_sg_refs, M_XENBLOCKFRONT);
1066 cm->cm_sg_refs = NULL;
1067 }
1068
1069 if (cm->cm_indirectionpages != NULL) {
1070 gnttab_end_foreign_access_references(
1071 sc->xbd_max_request_indirectpages,
1072 &cm->cm_indirectionrefs[0]);
1073 contigfree(cm->cm_indirectionpages, PAGE_SIZE *
1074 sc->xbd_max_request_indirectpages,
1075 M_XENBLOCKFRONT);
1076 cm->cm_indirectionpages = NULL;
1077 }
1078
1079 bus_dmamap_destroy(sc->xbd_io_dmat, cm->cm_map);
1080 }
1081 free(sc->xbd_shadow, M_XENBLOCKFRONT);
1082 sc->xbd_shadow = NULL;
1083
1084 bus_dma_tag_destroy(sc->xbd_io_dmat);
1085
1086 xbd_initq_cm(sc, XBD_Q_FREE);
1087 xbd_initq_cm(sc, XBD_Q_READY);
1088 xbd_initq_cm(sc, XBD_Q_COMPLETE);
1089 }
1090
1091 xen_intr_unbind(&sc->xen_intr_handle);
1092
1093 }
1094
1095 /*--------------------------- State Change Handlers --------------------------*/
1096 static void
xbd_initialize(struct xbd_softc * sc)1097 xbd_initialize(struct xbd_softc *sc)
1098 {
1099 const char *otherend_path;
1100 const char *node_path;
1101 uint32_t max_ring_page_order;
1102 int error;
1103
1104 if (xenbus_get_state(sc->xbd_dev) != XenbusStateInitialising) {
1105 /* Initialization has already been performed. */
1106 return;
1107 }
1108
1109 /*
1110 * Protocol defaults valid even if negotiation for a
1111 * setting fails.
1112 */
1113 max_ring_page_order = 0;
1114 sc->xbd_ring_pages = 1;
1115
1116 /*
1117 * Protocol negotiation.
1118 *
1119 * \note xs_gather() returns on the first encountered error, so
1120 * we must use independent calls in order to guarantee
1121 * we don't miss information in a sparsly populated back-end
1122 * tree.
1123 *
1124 * \note xs_scanf() does not update variables for unmatched
1125 * fields.
1126 */
1127 otherend_path = xenbus_get_otherend_path(sc->xbd_dev);
1128 node_path = xenbus_get_node(sc->xbd_dev);
1129
1130 /* Support both backend schemes for relaying ring page limits. */
1131 (void)xs_scanf(XST_NIL, otherend_path,
1132 "max-ring-page-order", NULL, "%" PRIu32,
1133 &max_ring_page_order);
1134 sc->xbd_ring_pages = 1 << max_ring_page_order;
1135 (void)xs_scanf(XST_NIL, otherend_path,
1136 "max-ring-pages", NULL, "%" PRIu32,
1137 &sc->xbd_ring_pages);
1138 if (sc->xbd_ring_pages < 1)
1139 sc->xbd_ring_pages = 1;
1140
1141 if (sc->xbd_ring_pages > XBD_MAX_RING_PAGES) {
1142 device_printf(sc->xbd_dev,
1143 "Back-end specified ring-pages of %u "
1144 "limited to front-end limit of %u.\n",
1145 sc->xbd_ring_pages, XBD_MAX_RING_PAGES);
1146 sc->xbd_ring_pages = XBD_MAX_RING_PAGES;
1147 }
1148
1149 if (powerof2(sc->xbd_ring_pages) == 0) {
1150 uint32_t new_page_limit;
1151
1152 new_page_limit = 0x01 << (fls(sc->xbd_ring_pages) - 1);
1153 device_printf(sc->xbd_dev,
1154 "Back-end specified ring-pages of %u "
1155 "is not a power of 2. Limited to %u.\n",
1156 sc->xbd_ring_pages, new_page_limit);
1157 sc->xbd_ring_pages = new_page_limit;
1158 }
1159
1160 sc->xbd_max_requests =
1161 BLKIF_MAX_RING_REQUESTS(sc->xbd_ring_pages * PAGE_SIZE);
1162 if (sc->xbd_max_requests > XBD_MAX_REQUESTS) {
1163 device_printf(sc->xbd_dev,
1164 "Back-end specified max_requests of %u "
1165 "limited to front-end limit of %zu.\n",
1166 sc->xbd_max_requests, XBD_MAX_REQUESTS);
1167 sc->xbd_max_requests = XBD_MAX_REQUESTS;
1168 }
1169
1170 if (xbd_alloc_ring(sc) != 0)
1171 return;
1172
1173 /* Support both backend schemes for relaying ring page limits. */
1174 if (sc->xbd_ring_pages > 1) {
1175 error = xs_printf(XST_NIL, node_path,
1176 "num-ring-pages","%u",
1177 sc->xbd_ring_pages);
1178 if (error) {
1179 xenbus_dev_fatal(sc->xbd_dev, error,
1180 "writing %s/num-ring-pages",
1181 node_path);
1182 return;
1183 }
1184
1185 error = xs_printf(XST_NIL, node_path,
1186 "ring-page-order", "%u",
1187 fls(sc->xbd_ring_pages) - 1);
1188 if (error) {
1189 xenbus_dev_fatal(sc->xbd_dev, error,
1190 "writing %s/ring-page-order",
1191 node_path);
1192 return;
1193 }
1194 }
1195
1196 error = xs_printf(XST_NIL, node_path, "event-channel",
1197 "%u", xen_intr_port(sc->xen_intr_handle));
1198 if (error) {
1199 xenbus_dev_fatal(sc->xbd_dev, error,
1200 "writing %s/event-channel",
1201 node_path);
1202 return;
1203 }
1204
1205 error = xs_printf(XST_NIL, node_path, "protocol",
1206 "%s", XEN_IO_PROTO_ABI_NATIVE);
1207 if (error) {
1208 xenbus_dev_fatal(sc->xbd_dev, error,
1209 "writing %s/protocol",
1210 node_path);
1211 return;
1212 }
1213
1214 xenbus_set_state(sc->xbd_dev, XenbusStateInitialised);
1215 }
1216
1217 /*
1218 * Invoked when the backend is finally 'ready' (and has published
1219 * the details about the physical device - #sectors, size, etc).
1220 */
1221 static void
xbd_connect(struct xbd_softc * sc)1222 xbd_connect(struct xbd_softc *sc)
1223 {
1224 device_t dev = sc->xbd_dev;
1225 blkif_sector_t sectors;
1226 unsigned long sector_size, phys_sector_size;
1227 unsigned int binfo;
1228 int err, feature_barrier, feature_flush;
1229 int i, j;
1230
1231 DPRINTK("blkfront.c:connect:%s.\n", xenbus_get_otherend_path(dev));
1232
1233 if (sc->xbd_state == XBD_STATE_SUSPENDED) {
1234 return;
1235 }
1236
1237 if (sc->xbd_state == XBD_STATE_CONNECTED) {
1238 struct disk *disk;
1239
1240 disk = sc->xbd_disk;
1241 if (disk == NULL) {
1242 return;
1243 }
1244 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1245 "sectors", "%"PRIu64, §ors, NULL);
1246 if (err != 0) {
1247 xenbus_dev_error(dev, err,
1248 "reading sectors at %s",
1249 xenbus_get_otherend_path(dev));
1250 return;
1251 }
1252 disk->d_mediasize = disk->d_sectorsize * sectors;
1253 err = disk_resize(disk, M_NOWAIT);
1254 if (err) {
1255 xenbus_dev_error(dev, err,
1256 "unable to resize disk %s%u",
1257 disk->d_name, disk->d_unit);
1258 return;
1259 }
1260 device_printf(sc->xbd_dev,
1261 "changed capacity to %jd\n",
1262 (intmax_t)disk->d_mediasize);
1263 return;
1264 }
1265
1266 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1267 "sectors", "%"PRIu64, §ors,
1268 "info", "%u", &binfo,
1269 "sector-size", "%lu", §or_size,
1270 NULL);
1271 if (err) {
1272 xenbus_dev_fatal(dev, err,
1273 "reading backend fields at %s",
1274 xenbus_get_otherend_path(dev));
1275 return;
1276 }
1277 if ((sectors == 0) || (sector_size == 0)) {
1278 xenbus_dev_fatal(dev, 0,
1279 "invalid parameters from %s:"
1280 " sectors = %"PRIu64", sector_size = %lu",
1281 xenbus_get_otherend_path(dev),
1282 sectors, sector_size);
1283 return;
1284 }
1285 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1286 "physical-sector-size", "%lu", &phys_sector_size,
1287 NULL);
1288 if (err || phys_sector_size <= sector_size)
1289 phys_sector_size = 0;
1290 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1291 "feature-barrier", "%d", &feature_barrier,
1292 NULL);
1293 if (err == 0 && feature_barrier != 0)
1294 sc->xbd_flags |= XBDF_BARRIER;
1295
1296 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1297 "feature-flush-cache", "%d", &feature_flush,
1298 NULL);
1299 if (err == 0 && feature_flush != 0)
1300 sc->xbd_flags |= XBDF_FLUSH;
1301
1302 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1303 "feature-max-indirect-segments", "%" PRIu32,
1304 &sc->xbd_max_request_segments, NULL);
1305 if ((err != 0) || (xbd_enable_indirect == 0))
1306 sc->xbd_max_request_segments = 0;
1307 if (sc->xbd_max_request_segments > XBD_MAX_INDIRECT_SEGMENTS)
1308 sc->xbd_max_request_segments = XBD_MAX_INDIRECT_SEGMENTS;
1309 if (sc->xbd_max_request_segments > XBD_SIZE_TO_SEGS(maxphys))
1310 sc->xbd_max_request_segments = XBD_SIZE_TO_SEGS(maxphys);
1311 sc->xbd_max_request_indirectpages =
1312 XBD_INDIRECT_SEGS_TO_PAGES(sc->xbd_max_request_segments);
1313 if (sc->xbd_max_request_segments < BLKIF_MAX_SEGMENTS_PER_REQUEST)
1314 sc->xbd_max_request_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST;
1315 sc->xbd_max_request_size =
1316 XBD_SEGS_TO_SIZE(sc->xbd_max_request_segments);
1317
1318 /* Allocate datastructures based on negotiated values. */
1319 err = bus_dma_tag_create(
1320 bus_get_dma_tag(sc->xbd_dev), /* parent */
1321 512, PAGE_SIZE, /* algnmnt, boundary */
1322 BUS_SPACE_MAXADDR, /* lowaddr */
1323 BUS_SPACE_MAXADDR, /* highaddr */
1324 NULL, NULL, /* filter, filterarg */
1325 sc->xbd_max_request_size,
1326 sc->xbd_max_request_segments,
1327 PAGE_SIZE, /* maxsegsize */
1328 BUS_DMA_ALLOCNOW, /* flags */
1329 busdma_lock_mutex, /* lockfunc */
1330 &sc->xbd_io_lock, /* lockarg */
1331 &sc->xbd_io_dmat);
1332 if (err != 0) {
1333 xenbus_dev_fatal(sc->xbd_dev, err,
1334 "Cannot allocate parent DMA tag\n");
1335 return;
1336 }
1337
1338 /* Per-transaction data allocation. */
1339 sc->xbd_shadow = malloc(sizeof(*sc->xbd_shadow) * sc->xbd_max_requests,
1340 M_XENBLOCKFRONT, M_NOWAIT|M_ZERO);
1341 if (sc->xbd_shadow == NULL) {
1342 bus_dma_tag_destroy(sc->xbd_io_dmat);
1343 xenbus_dev_fatal(sc->xbd_dev, ENOMEM,
1344 "Cannot allocate request structures\n");
1345 return;
1346 }
1347
1348 for (i = 0; i < sc->xbd_max_requests; i++) {
1349 struct xbd_command *cm;
1350 void * indirectpages;
1351
1352 cm = &sc->xbd_shadow[i];
1353 cm->cm_sg_refs = malloc(
1354 sizeof(grant_ref_t) * sc->xbd_max_request_segments,
1355 M_XENBLOCKFRONT, M_NOWAIT);
1356 if (cm->cm_sg_refs == NULL)
1357 break;
1358 cm->cm_id = i;
1359 cm->cm_flags = XBDCF_INITIALIZER;
1360 cm->cm_sc = sc;
1361 if (bus_dmamap_create(sc->xbd_io_dmat, 0, &cm->cm_map) != 0)
1362 break;
1363 if (sc->xbd_max_request_indirectpages > 0) {
1364 indirectpages = contigmalloc(
1365 PAGE_SIZE * sc->xbd_max_request_indirectpages,
1366 M_XENBLOCKFRONT, M_ZERO | M_NOWAIT, 0, ~0,
1367 PAGE_SIZE, 0);
1368 if (indirectpages == NULL)
1369 sc->xbd_max_request_indirectpages = 0;
1370 } else {
1371 indirectpages = NULL;
1372 }
1373 for (j = 0; j < sc->xbd_max_request_indirectpages; j++) {
1374 if (gnttab_grant_foreign_access(
1375 xenbus_get_otherend_id(sc->xbd_dev),
1376 (vtophys(indirectpages) >> PAGE_SHIFT) + j,
1377 1 /* grant read-only access */,
1378 &cm->cm_indirectionrefs[j]))
1379 break;
1380 }
1381 if (j < sc->xbd_max_request_indirectpages) {
1382 contigfree(indirectpages,
1383 PAGE_SIZE * sc->xbd_max_request_indirectpages,
1384 M_XENBLOCKFRONT);
1385 break;
1386 }
1387 cm->cm_indirectionpages = indirectpages;
1388 xbd_free_command(cm);
1389 }
1390
1391 if (sc->xbd_disk == NULL) {
1392 device_printf(dev, "%juMB <%s> at %s",
1393 (uintmax_t) sectors / (1048576 / sector_size),
1394 device_get_desc(dev),
1395 xenbus_get_node(dev));
1396 bus_print_child_footer(device_get_parent(dev), dev);
1397
1398 xbd_instance_create(sc, sectors, sc->xbd_vdevice, binfo,
1399 sector_size, phys_sector_size);
1400 }
1401
1402 (void)xenbus_set_state(dev, XenbusStateConnected);
1403
1404 /* Kick pending requests. */
1405 mtx_lock(&sc->xbd_io_lock);
1406 sc->xbd_state = XBD_STATE_CONNECTED;
1407 xbd_startio(sc);
1408 sc->xbd_flags |= XBDF_READY;
1409 mtx_unlock(&sc->xbd_io_lock);
1410 }
1411
1412 /**
1413 * Handle the change of state of the backend to Closing. We must delete our
1414 * device-layer structures now, to ensure that writes are flushed through to
1415 * the backend. Once this is done, we can switch to Closed in
1416 * acknowledgement.
1417 */
1418 static void
xbd_closing(device_t dev)1419 xbd_closing(device_t dev)
1420 {
1421 struct xbd_softc *sc = device_get_softc(dev);
1422
1423 xenbus_set_state(dev, XenbusStateClosing);
1424
1425 DPRINTK("xbd_closing: %s removed\n", xenbus_get_node(dev));
1426
1427 if (sc->xbd_disk != NULL) {
1428 disk_destroy(sc->xbd_disk);
1429 sc->xbd_disk = NULL;
1430 }
1431
1432 xenbus_set_state(dev, XenbusStateClosed);
1433 }
1434
1435 /*---------------------------- NewBus Entrypoints ----------------------------*/
1436 static int
xbd_probe(device_t dev)1437 xbd_probe(device_t dev)
1438 {
1439 if (strcmp(xenbus_get_type(dev), "vbd") != 0)
1440 return (ENXIO);
1441
1442 if (xen_hvm_domain() && xen_disable_pv_disks != 0)
1443 return (ENXIO);
1444
1445 if (xen_hvm_domain()) {
1446 int error;
1447 char *type;
1448
1449 /*
1450 * When running in an HVM domain, IDE disk emulation is
1451 * disabled early in boot so that native drivers will
1452 * not see emulated hardware. However, CDROM device
1453 * emulation cannot be disabled.
1454 *
1455 * Through use of FreeBSD's vm_guest and xen_hvm_domain()
1456 * APIs, we could modify the native CDROM driver to fail its
1457 * probe when running under Xen. Unfortunatlely, the PV
1458 * CDROM support in XenServer (up through at least version
1459 * 6.2) isn't functional, so we instead rely on the emulated
1460 * CDROM instance, and fail to attach the PV one here in
1461 * the blkfront driver.
1462 */
1463 error = xs_read(XST_NIL, xenbus_get_node(dev),
1464 "device-type", NULL, (void **) &type);
1465 if (error)
1466 return (ENXIO);
1467
1468 if (strncmp(type, "cdrom", 5) == 0) {
1469 free(type, M_XENSTORE);
1470 return (ENXIO);
1471 }
1472 free(type, M_XENSTORE);
1473 }
1474
1475 device_set_desc(dev, "Virtual Block Device");
1476 device_quiet(dev);
1477 return (0);
1478 }
1479
1480 /*
1481 * Setup supplies the backend dir, virtual device. We place an event
1482 * channel and shared frame entries. We watch backend to wait if it's
1483 * ok.
1484 */
1485 static int
xbd_attach(device_t dev)1486 xbd_attach(device_t dev)
1487 {
1488 struct xbd_softc *sc;
1489 const char *name;
1490 uint32_t vdevice;
1491 int error;
1492 int i;
1493 int unit;
1494
1495 /* FIXME: Use dynamic device id if this is not set. */
1496 error = xs_scanf(XST_NIL, xenbus_get_node(dev),
1497 "virtual-device", NULL, "%" PRIu32, &vdevice);
1498 if (error)
1499 error = xs_scanf(XST_NIL, xenbus_get_node(dev),
1500 "virtual-device-ext", NULL, "%" PRIu32, &vdevice);
1501 if (error) {
1502 xenbus_dev_fatal(dev, error, "reading virtual-device");
1503 device_printf(dev, "Couldn't determine virtual device.\n");
1504 return (error);
1505 }
1506
1507 xbd_vdevice_to_unit(vdevice, &unit, &name);
1508 if (!strcmp(name, "xbd"))
1509 device_set_unit(dev, unit);
1510
1511 sc = device_get_softc(dev);
1512 mtx_init(&sc->xbd_io_lock, "blkfront i/o lock", NULL, MTX_DEF);
1513 xbd_initqs(sc);
1514 for (i = 0; i < XBD_MAX_RING_PAGES; i++)
1515 sc->xbd_ring_ref[i] = GRANT_REF_INVALID;
1516
1517 sc->xbd_dev = dev;
1518 sc->xbd_vdevice = vdevice;
1519 sc->xbd_state = XBD_STATE_DISCONNECTED;
1520
1521 xbd_setup_sysctl(sc);
1522
1523 /* Wait for backend device to publish its protocol capabilities. */
1524 xenbus_set_state(dev, XenbusStateInitialising);
1525
1526 return (0);
1527 }
1528
1529 static int
xbd_detach(device_t dev)1530 xbd_detach(device_t dev)
1531 {
1532 struct xbd_softc *sc = device_get_softc(dev);
1533
1534 DPRINTK("%s: %s removed\n", __func__, xenbus_get_node(dev));
1535
1536 xbd_free(sc);
1537 mtx_destroy(&sc->xbd_io_lock);
1538
1539 return 0;
1540 }
1541
1542 static int
xbd_suspend(device_t dev)1543 xbd_suspend(device_t dev)
1544 {
1545 struct xbd_softc *sc = device_get_softc(dev);
1546 int retval;
1547 int saved_state;
1548
1549 /* Prevent new requests being issued until we fix things up. */
1550 mtx_lock(&sc->xbd_io_lock);
1551 saved_state = sc->xbd_state;
1552 sc->xbd_state = XBD_STATE_SUSPENDED;
1553
1554 /* Wait for outstanding I/O to drain. */
1555 retval = 0;
1556 while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
1557 if (msleep(&sc->xbd_cm_q[XBD_Q_BUSY], &sc->xbd_io_lock,
1558 PRIBIO, "blkf_susp", 30 * hz) == EWOULDBLOCK) {
1559 retval = EBUSY;
1560 break;
1561 }
1562 }
1563 mtx_unlock(&sc->xbd_io_lock);
1564
1565 if (retval != 0)
1566 sc->xbd_state = saved_state;
1567
1568 return (retval);
1569 }
1570
1571 static int
xbd_resume(device_t dev)1572 xbd_resume(device_t dev)
1573 {
1574 struct xbd_softc *sc = device_get_softc(dev);
1575
1576 if (xen_suspend_cancelled) {
1577 sc->xbd_state = XBD_STATE_CONNECTED;
1578 return (0);
1579 }
1580
1581 DPRINTK("xbd_resume: %s\n", xenbus_get_node(dev));
1582
1583 xbd_free(sc);
1584 xbd_initialize(sc);
1585 return (0);
1586 }
1587
1588 /**
1589 * Callback received when the backend's state changes.
1590 */
1591 static void
xbd_backend_changed(device_t dev,XenbusState backend_state)1592 xbd_backend_changed(device_t dev, XenbusState backend_state)
1593 {
1594 struct xbd_softc *sc = device_get_softc(dev);
1595
1596 DPRINTK("backend_state=%d\n", backend_state);
1597
1598 switch (backend_state) {
1599 case XenbusStateUnknown:
1600 case XenbusStateInitialising:
1601 case XenbusStateReconfigured:
1602 case XenbusStateReconfiguring:
1603 case XenbusStateClosed:
1604 break;
1605
1606 case XenbusStateInitWait:
1607 case XenbusStateInitialised:
1608 xbd_initialize(sc);
1609 break;
1610
1611 case XenbusStateConnected:
1612 xbd_initialize(sc);
1613 xbd_connect(sc);
1614 break;
1615
1616 case XenbusStateClosing:
1617 if (sc->xbd_users > 0) {
1618 device_printf(dev, "detaching with pending users\n");
1619 KASSERT(sc->xbd_disk != NULL,
1620 ("NULL disk with pending users\n"));
1621 disk_gone(sc->xbd_disk);
1622 } else {
1623 xbd_closing(dev);
1624 }
1625 break;
1626 }
1627 }
1628
1629 /*---------------------------- NewBus Registration ---------------------------*/
1630 static device_method_t xbd_methods[] = {
1631 /* Device interface */
1632 DEVMETHOD(device_probe, xbd_probe),
1633 DEVMETHOD(device_attach, xbd_attach),
1634 DEVMETHOD(device_detach, xbd_detach),
1635 DEVMETHOD(device_shutdown, bus_generic_shutdown),
1636 DEVMETHOD(device_suspend, xbd_suspend),
1637 DEVMETHOD(device_resume, xbd_resume),
1638
1639 /* Xenbus interface */
1640 DEVMETHOD(xenbus_otherend_changed, xbd_backend_changed),
1641
1642 { 0, 0 }
1643 };
1644
1645 static driver_t xbd_driver = {
1646 "xbd",
1647 xbd_methods,
1648 sizeof(struct xbd_softc),
1649 };
1650 devclass_t xbd_devclass;
1651
1652 DRIVER_MODULE(xbd, xenbusb_front, xbd_driver, xbd_devclass, 0, 0);
1653