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