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