aboutsummaryrefslogtreecommitdiff
path: root/hw/scsi-bus.c
blob: 8b1a4122106e30d9a1e43bb19361ef660dd7e3c7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
#include "hw.h"
#include "qemu-error.h"
#include "scsi.h"
#include "scsi-defs.h"
#include "qdev.h"
#include "blockdev.h"
#include "trace.h"

static char *scsibus_get_fw_dev_path(DeviceState *dev);

static struct BusInfo scsi_bus_info = {
    .name  = "SCSI",
    .size  = sizeof(SCSIBus),
    .get_fw_dev_path = scsibus_get_fw_dev_path,
    .props = (Property[]) {
        DEFINE_PROP_UINT32("scsi-id", SCSIDevice, id, -1),
        DEFINE_PROP_END_OF_LIST(),
    },
};
static int next_scsi_bus;

/* Create a scsi bus, and attach devices to it.  */
void scsi_bus_new(SCSIBus *bus, DeviceState *host, int tcq, int ndev,
                  const SCSIBusOps *ops)
{
    qbus_create_inplace(&bus->qbus, &scsi_bus_info, host, NULL);
    bus->busnr = next_scsi_bus++;
    bus->tcq = tcq;
    bus->ndev = ndev;
    bus->ops = ops;
    bus->qbus.allow_hotplug = 1;
}

static int scsi_qdev_init(DeviceState *qdev, DeviceInfo *base)
{
    SCSIDevice *dev = DO_UPCAST(SCSIDevice, qdev, qdev);
    SCSIDeviceInfo *info = DO_UPCAST(SCSIDeviceInfo, qdev, base);
    SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, dev->qdev.parent_bus);
    int rc = -1;

    if (dev->id == -1) {
        for (dev->id = 0; dev->id < bus->ndev; dev->id++) {
            if (bus->devs[dev->id] == NULL)
                break;
        }
    }
    if (dev->id >= bus->ndev) {
        error_report("bad scsi device id: %d", dev->id);
        goto err;
    }

    if (bus->devs[dev->id]) {
        qdev_free(&bus->devs[dev->id]->qdev);
    }
    bus->devs[dev->id] = dev;

    dev->info = info;
    QTAILQ_INIT(&dev->requests);
    rc = dev->info->init(dev);
    if (rc != 0) {
        bus->devs[dev->id] = NULL;
    }

err:
    return rc;
}

static int scsi_qdev_exit(DeviceState *qdev)
{
    SCSIDevice *dev = DO_UPCAST(SCSIDevice, qdev, qdev);
    SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, dev->qdev.parent_bus);

    assert(bus->devs[dev->id] != NULL);
    if (bus->devs[dev->id]->info->destroy) {
        bus->devs[dev->id]->info->destroy(bus->devs[dev->id]);
    }
    bus->devs[dev->id] = NULL;
    return 0;
}

void scsi_qdev_register(SCSIDeviceInfo *info)
{
    info->qdev.bus_info = &scsi_bus_info;
    info->qdev.init     = scsi_qdev_init;
    info->qdev.unplug   = qdev_simple_unplug_cb;
    info->qdev.exit     = scsi_qdev_exit;
    qdev_register(&info->qdev);
}

/* handle legacy '-drive if=scsi,...' cmd line args */
SCSIDevice *scsi_bus_legacy_add_drive(SCSIBus *bus, BlockDriverState *bdrv,
                                      int unit, bool removable)
{
    const char *driver;
    DeviceState *dev;

    driver = bdrv_is_sg(bdrv) ? "scsi-generic" : "scsi-disk";
    dev = qdev_create(&bus->qbus, driver);
    qdev_prop_set_uint32(dev, "scsi-id", unit);
    if (qdev_prop_exists(dev, "removable")) {
        qdev_prop_set_bit(dev, "removable", removable);
    }
    if (qdev_prop_set_drive(dev, "drive", bdrv) < 0) {
        qdev_free(dev);
        return NULL;
    }
    if (qdev_init(dev) < 0)
        return NULL;
    return DO_UPCAST(SCSIDevice, qdev, dev);
}

int scsi_bus_legacy_handle_cmdline(SCSIBus *bus)
{
    Location loc;
    DriveInfo *dinfo;
    int res = 0, unit;

    loc_push_none(&loc);
    for (unit = 0; unit < bus->ndev; unit++) {
        dinfo = drive_get(IF_SCSI, bus->busnr, unit);
        if (dinfo == NULL) {
            continue;
        }
        qemu_opts_loc_restore(dinfo->opts);
        if (!scsi_bus_legacy_add_drive(bus, dinfo->bdrv, unit, false)) {
            res = -1;
            break;
        }
    }
    loc_pop(&loc);
    return res;
}

SCSIRequest *scsi_req_alloc(size_t size, SCSIDevice *d, uint32_t tag,
                            uint32_t lun, void *hba_private)
{
    SCSIRequest *req;

    req = qemu_mallocz(size);
    req->refcount = 1;
    req->bus = scsi_bus_from_device(d);
    req->dev = d;
    req->tag = tag;
    req->lun = lun;
    req->hba_private = hba_private;
    req->status = -1;
    trace_scsi_req_alloc(req->dev->id, req->lun, req->tag);
    return req;
}

SCSIRequest *scsi_req_new(SCSIDevice *d, uint32_t tag, uint32_t lun,
                          void *hba_private)
{
    return d->info->alloc_req(d, tag, lun, hba_private);
}

uint8_t *scsi_req_get_buf(SCSIRequest *req)
{
    return req->dev->info->get_buf(req);
}

int scsi_req_get_sense(SCSIRequest *req, uint8_t *buf, int len)
{
    if (req->dev->info->get_sense) {
        return req->dev->info->get_sense(req, buf, len);
    } else {
        return 0;
    }
}

int32_t scsi_req_enqueue(SCSIRequest *req, uint8_t *buf)
{
    int32_t rc;

    assert(!req->enqueued);
    scsi_req_ref(req);
    req->enqueued = true;
    QTAILQ_INSERT_TAIL(&req->dev->requests, req, next);

    scsi_req_ref(req);
    rc = req->dev->info->send_command(req, buf);
    scsi_req_unref(req);
    return rc;
}

static void scsi_req_dequeue(SCSIRequest *req)
{
    trace_scsi_req_dequeue(req->dev->id, req->lun, req->tag);
    if (req->enqueued) {
        QTAILQ_REMOVE(&req->dev->requests, req, next);
        req->enqueued = false;
        scsi_req_unref(req);
    }
}

static int scsi_req_length(SCSIRequest *req, uint8_t *cmd)
{
    switch (cmd[0] >> 5) {
    case 0:
        req->cmd.xfer = cmd[4];
        req->cmd.len = 6;
        /* length 0 means 256 blocks */
        if (req->cmd.xfer == 0)
            req->cmd.xfer = 256;
        break;
    case 1:
    case 2:
        req->cmd.xfer = cmd[8] | (cmd[7] << 8);
        req->cmd.len = 10;
        break;
    case 4:
        req->cmd.xfer = cmd[13] | (cmd[12] << 8) | (cmd[11] << 16) | (cmd[10] << 24);
        req->cmd.len = 16;
        break;
    case 5:
        req->cmd.xfer = cmd[9] | (cmd[8] << 8) | (cmd[7] << 16) | (cmd[6] << 24);
        req->cmd.len = 12;
        break;
    default:
        trace_scsi_req_parse_bad(req->dev->id, req->lun, req->tag, cmd[0]);
        return -1;
    }

    switch(cmd[0]) {
    case TEST_UNIT_READY:
    case REZERO_UNIT:
    case START_STOP:
    case SEEK_6:
    case WRITE_FILEMARKS:
    case SPACE:
    case RESERVE:
    case RELEASE:
    case ERASE:
    case ALLOW_MEDIUM_REMOVAL:
    case VERIFY:
    case SEEK_10:
    case SYNCHRONIZE_CACHE:
    case LOCK_UNLOCK_CACHE:
    case LOAD_UNLOAD:
    case SET_CD_SPEED:
    case SET_LIMITS:
    case WRITE_LONG:
    case MOVE_MEDIUM:
    case UPDATE_BLOCK:
        req->cmd.xfer = 0;
        break;
    case MODE_SENSE:
        break;
    case WRITE_SAME:
        req->cmd.xfer = 1;
        break;
    case READ_CAPACITY:
        req->cmd.xfer = 8;
        break;
    case READ_BLOCK_LIMITS:
        req->cmd.xfer = 6;
        break;
    case READ_POSITION:
        req->cmd.xfer = 20;
        break;
    case SEND_VOLUME_TAG:
        req->cmd.xfer *= 40;
        break;
    case MEDIUM_SCAN:
        req->cmd.xfer *= 8;
        break;
    case WRITE_10:
    case WRITE_VERIFY:
    case WRITE_6:
    case WRITE_12:
    case WRITE_VERIFY_12:
    case WRITE_16:
    case WRITE_VERIFY_16:
        req->cmd.xfer *= req->dev->blocksize;
        break;
    case READ_10:
    case READ_6:
    case READ_REVERSE:
    case RECOVER_BUFFERED_DATA:
    case READ_12:
    case READ_16:
        req->cmd.xfer *= req->dev->blocksize;
        break;
    case INQUIRY:
        req->cmd.xfer = cmd[4] | (cmd[3] << 8);
        break;
    case MAINTENANCE_OUT:
    case MAINTENANCE_IN:
        if (req->dev->type == TYPE_ROM) {
            /* GPCMD_REPORT_KEY and GPCMD_SEND_KEY from multi media commands */
            req->cmd.xfer = cmd[9] | (cmd[8] << 8);
        }
        break;
    }
    return 0;
}

static int scsi_req_stream_length(SCSIRequest *req, uint8_t *cmd)
{
    switch(cmd[0]) {
    /* stream commands */
    case READ_6:
    case READ_REVERSE:
    case RECOVER_BUFFERED_DATA:
    case WRITE_6:
        req->cmd.len = 6;
        req->cmd.xfer = cmd[4] | (cmd[3] << 8) | (cmd[2] << 16);
        if (cmd[1] & 0x01) /* fixed */
            req->cmd.xfer *= req->dev->blocksize;
        break;
    case REWIND:
    case START_STOP:
        req->cmd.len = 6;
        req->cmd.xfer = 0;
        break;
    /* generic commands */
    default:
        return scsi_req_length(req, cmd);
    }
    return 0;
}

static void scsi_req_xfer_mode(SCSIRequest *req)
{
    switch (req->cmd.buf[0]) {
    case WRITE_6:
    case WRITE_10:
    case WRITE_VERIFY:
    case WRITE_12:
    case WRITE_VERIFY_12:
    case WRITE_16:
    case WRITE_VERIFY_16:
    case COPY:
    case COPY_VERIFY:
    case COMPARE:
    case CHANGE_DEFINITION:
    case LOG_SELECT:
    case MODE_SELECT:
    case MODE_SELECT_10:
    case SEND_DIAGNOSTIC:
    case WRITE_BUFFER:
    case FORMAT_UNIT:
    case REASSIGN_BLOCKS:
    case SEARCH_EQUAL:
    case SEARCH_HIGH:
    case SEARCH_LOW:
    case UPDATE_BLOCK:
    case WRITE_LONG:
    case WRITE_SAME:
    case SEARCH_HIGH_12:
    case SEARCH_EQUAL_12:
    case SEARCH_LOW_12:
    case SET_WINDOW:
    case MEDIUM_SCAN:
    case SEND_VOLUME_TAG:
    case WRITE_LONG_2:
    case PERSISTENT_RESERVE_OUT:
    case MAINTENANCE_OUT:
        req->cmd.mode = SCSI_XFER_TO_DEV;
        break;
    default:
        if (req->cmd.xfer)
            req->cmd.mode = SCSI_XFER_FROM_DEV;
        else {
            req->cmd.mode = SCSI_XFER_NONE;
        }
        break;
    }
}

static uint64_t scsi_req_lba(SCSIRequest *req)
{
    uint8_t *buf = req->cmd.buf;
    uint64_t lba;

    switch (buf[0] >> 5) {
    case 0:
        lba = (uint64_t) buf[3] | ((uint64_t) buf[2] << 8) |
              (((uint64_t) buf[1] & 0x1f) << 16);
        break;
    case 1:
    case 2:
        lba = (uint64_t) buf[5] | ((uint64_t) buf[4] << 8) |
              ((uint64_t) buf[3] << 16) | ((uint64_t) buf[2] << 24);
        break;
    case 4:
        lba = (uint64_t) buf[9] | ((uint64_t) buf[8] << 8) |
              ((uint64_t) buf[7] << 16) | ((uint64_t) buf[6] << 24) |
              ((uint64_t) buf[5] << 32) | ((uint64_t) buf[4] << 40) |
              ((uint64_t) buf[3] << 48) | ((uint64_t) buf[2] << 56);
        break;
    case 5:
        lba = (uint64_t) buf[5] | ((uint64_t) buf[4] << 8) |
              ((uint64_t) buf[3] << 16) | ((uint64_t) buf[2] << 24);
        break;
    default:
        lba = -1;

    }
    return lba;
}

int scsi_req_parse(SCSIRequest *req, uint8_t *buf)
{
    int rc;

    if (req->dev->type == TYPE_TAPE) {
        rc = scsi_req_stream_length(req, buf);
    } else {
        rc = scsi_req_length(req, buf);
    }
    if (rc != 0)
        return rc;

    memcpy(req->cmd.buf, buf, req->cmd.len);
    scsi_req_xfer_mode(req);
    req->cmd.lba = scsi_req_lba(req);
    trace_scsi_req_parsed(req->dev->id, req->lun, req->tag, buf[0],
                          req->cmd.mode, req->cmd.xfer);
    if (req->cmd.lba != -1) {
        trace_scsi_req_parsed_lba(req->dev->id, req->lun, req->tag, buf[0],
                              req->cmd.lba);
    }
    return 0;
}

/*
 * Predefined sense codes
 */

/* No sense data available */
const struct SCSISense sense_code_NO_SENSE = {
    .key = NO_SENSE , .asc = 0x00 , .ascq = 0x00
};

/* LUN not ready, Manual intervention required */
const struct SCSISense sense_code_LUN_NOT_READY = {
    .key = NOT_READY, .asc = 0x04, .ascq = 0x03
};

/* LUN not ready, Medium not present */
const struct SCSISense sense_code_NO_MEDIUM = {
    .key = NOT_READY, .asc = 0x3a, .ascq = 0x00
};

/* Hardware error, internal target failure */
const struct SCSISense sense_code_TARGET_FAILURE = {
    .key = HARDWARE_ERROR, .asc = 0x44, .ascq = 0x00
};

/* Illegal request, invalid command operation code */
const struct SCSISense sense_code_INVALID_OPCODE = {
    .key = ILLEGAL_REQUEST, .asc = 0x20, .ascq = 0x00
};

/* Illegal request, LBA out of range */
const struct SCSISense sense_code_LBA_OUT_OF_RANGE = {
    .key = ILLEGAL_REQUEST, .asc = 0x21, .ascq = 0x00
};

/* Illegal request, Invalid field in CDB */
const struct SCSISense sense_code_INVALID_FIELD = {
    .key = ILLEGAL_REQUEST, .asc = 0x24, .ascq = 0x00
};

/* Illegal request, LUN not supported */
const struct SCSISense sense_code_LUN_NOT_SUPPORTED = {
    .key = ILLEGAL_REQUEST, .asc = 0x25, .ascq = 0x00
};

/* Command aborted, I/O process terminated */
const struct SCSISense sense_code_IO_ERROR = {
    .key = ABORTED_COMMAND, .asc = 0x00, .ascq = 0x06
};

/* Command aborted, I_T Nexus loss occurred */
const struct SCSISense sense_code_I_T_NEXUS_LOSS = {
    .key = ABORTED_COMMAND, .asc = 0x29, .ascq = 0x07
};

/* Command aborted, Logical Unit failure */
const struct SCSISense sense_code_LUN_FAILURE = {
    .key = ABORTED_COMMAND, .asc = 0x3e, .ascq = 0x01
};

/*
 * scsi_build_sense
 *
 * Build a sense buffer
 */
int scsi_build_sense(SCSISense sense, uint8_t *buf, int len, int fixed)
{
    if (!fixed && len < 8) {
        return 0;
    }

    memset(buf, 0, len);
    if (fixed) {
        /* Return fixed format sense buffer */
        buf[0] = 0xf0;
        buf[2] = sense.key;
        buf[7] = 7;
        buf[12] = sense.asc;
        buf[13] = sense.ascq;
        return MIN(len, 18);
    } else {
        /* Return descriptor format sense buffer */
        buf[0] = 0x72;
        buf[1] = sense.key;
        buf[2] = sense.asc;
        buf[3] = sense.ascq;
        return 8;
    }
}

static const char *scsi_command_name(uint8_t cmd)
{
    static const char *names[] = {
        [ TEST_UNIT_READY          ] = "TEST_UNIT_READY",
        [ REZERO_UNIT              ] = "REZERO_UNIT",
        /* REWIND and REZERO_UNIT use the same operation code */
        [ REQUEST_SENSE            ] = "REQUEST_SENSE",
        [ FORMAT_UNIT              ] = "FORMAT_UNIT",
        [ READ_BLOCK_LIMITS        ] = "READ_BLOCK_LIMITS",
        [ REASSIGN_BLOCKS          ] = "REASSIGN_BLOCKS",
        [ READ_6                   ] = "READ_6",
        [ WRITE_6                  ] = "WRITE_6",
        [ SEEK_6                   ] = "SEEK_6",
        [ READ_REVERSE             ] = "READ_REVERSE",
        [ WRITE_FILEMARKS          ] = "WRITE_FILEMARKS",
        [ SPACE                    ] = "SPACE",
        [ INQUIRY                  ] = "INQUIRY",
        [ RECOVER_BUFFERED_DATA    ] = "RECOVER_BUFFERED_DATA",
        [ MAINTENANCE_IN           ] = "MAINTENANCE_IN",
        [ MAINTENANCE_OUT          ] = "MAINTENANCE_OUT",
        [ MODE_SELECT              ] = "MODE_SELECT",
        [ RESERVE                  ] = "RESERVE",
        [ RELEASE                  ] = "RELEASE",
        [ COPY                     ] = "COPY",
        [ ERASE                    ] = "ERASE",
        [ MODE_SENSE               ] = "MODE_SENSE",
        [ START_STOP               ] = "START_STOP",
        [ RECEIVE_DIAGNOSTIC       ] = "RECEIVE_DIAGNOSTIC",
        [ SEND_DIAGNOSTIC          ] = "SEND_DIAGNOSTIC",
        [ ALLOW_MEDIUM_REMOVAL     ] = "ALLOW_MEDIUM_REMOVAL",

        [ SET_WINDOW               ] = "SET_WINDOW",
        [ READ_CAPACITY            ] = "READ_CAPACITY",
        [ READ_10                  ] = "READ_10",
        [ WRITE_10                 ] = "WRITE_10",
        [ SEEK_10                  ] = "SEEK_10",
        [ WRITE_VERIFY             ] = "WRITE_VERIFY",
        [ VERIFY                   ] = "VERIFY",
        [ SEARCH_HIGH              ] = "SEARCH_HIGH",
        [ SEARCH_EQUAL             ] = "SEARCH_EQUAL",
        [ SEARCH_LOW               ] = "SEARCH_LOW",
        [ SET_LIMITS               ] = "SET_LIMITS",
        [ PRE_FETCH                ] = "PRE_FETCH",
        /* READ_POSITION and PRE_FETCH use the same operation code */
        [ SYNCHRONIZE_CACHE        ] = "SYNCHRONIZE_CACHE",
        [ LOCK_UNLOCK_CACHE        ] = "LOCK_UNLOCK_CACHE",
        [ READ_DEFECT_DATA         ] = "READ_DEFECT_DATA",
        [ MEDIUM_SCAN              ] = "MEDIUM_SCAN",
        [ COMPARE                  ] = "COMPARE",
        [ COPY_VERIFY              ] = "COPY_VERIFY",
        [ WRITE_BUFFER             ] = "WRITE_BUFFER",
        [ READ_BUFFER              ] = "READ_BUFFER",
        [ UPDATE_BLOCK             ] = "UPDATE_BLOCK",
        [ READ_LONG                ] = "READ_LONG",
        [ WRITE_LONG               ] = "WRITE_LONG",
        [ CHANGE_DEFINITION        ] = "CHANGE_DEFINITION",
        [ WRITE_SAME               ] = "WRITE_SAME",
        [ READ_TOC                 ] = "READ_TOC",
        [ LOG_SELECT               ] = "LOG_SELECT",
        [ LOG_SENSE                ] = "LOG_SENSE",
        [ MODE_SELECT_10           ] = "MODE_SELECT_10",
        [ RESERVE_10               ] = "RESERVE_10",
        [ RELEASE_10               ] = "RELEASE_10",
        [ MODE_SENSE_10            ] = "MODE_SENSE_10",
        [ PERSISTENT_RESERVE_IN    ] = "PERSISTENT_RESERVE_IN",
        [ PERSISTENT_RESERVE_OUT   ] = "PERSISTENT_RESERVE_OUT",
        [ MOVE_MEDIUM              ] = "MOVE_MEDIUM",
        [ READ_12                  ] = "READ_12",
        [ WRITE_12                 ] = "WRITE_12",
        [ WRITE_VERIFY_12          ] = "WRITE_VERIFY_12",
        [ SEARCH_HIGH_12           ] = "SEARCH_HIGH_12",
        [ SEARCH_EQUAL_12          ] = "SEARCH_EQUAL_12",
        [ SEARCH_LOW_12            ] = "SEARCH_LOW_12",
        [ READ_ELEMENT_STATUS      ] = "READ_ELEMENT_STATUS",
        [ SEND_VOLUME_TAG          ] = "SEND_VOLUME_TAG",
        [ WRITE_LONG_2             ] = "WRITE_LONG_2",

        [ REPORT_DENSITY_SUPPORT   ] = "REPORT_DENSITY_SUPPORT",
        [ GET_CONFIGURATION        ] = "GET_CONFIGURATION",
        [ READ_16                  ] = "READ_16",
        [ WRITE_16                 ] = "WRITE_16",
        [ WRITE_VERIFY_16          ] = "WRITE_VERIFY_16",
        [ SERVICE_ACTION_IN        ] = "SERVICE_ACTION_IN",
        [ REPORT_LUNS              ] = "REPORT_LUNS",
        [ LOAD_UNLOAD              ] = "LOAD_UNLOAD",
        [ SET_CD_SPEED             ] = "SET_CD_SPEED",
        [ BLANK                    ] = "BLANK",
    };

    if (cmd >= ARRAY_SIZE(names) || names[cmd] == NULL)
        return "*UNKNOWN*";
    return names[cmd];
}

SCSIRequest *scsi_req_ref(SCSIRequest *req)
{
    req->refcount++;
    return req;
}

void scsi_req_unref(SCSIRequest *req)
{
    if (--req->refcount == 0) {
        if (req->dev->info->free_req) {
            req->dev->info->free_req(req);
        }
        qemu_free(req);
    }
}

/* Tell the device that we finished processing this chunk of I/O.  It
   will start the next chunk or complete the command.  */
void scsi_req_continue(SCSIRequest *req)
{
    trace_scsi_req_continue(req->dev->id, req->lun, req->tag);
    if (req->cmd.mode == SCSI_XFER_TO_DEV) {
        req->dev->info->write_data(req);
    } else {
        req->dev->info->read_data(req);
    }
}

/* Called by the devices when data is ready for the HBA.  The HBA should
   start a DMA operation to read or fill the device's data buffer.
   Once it completes, calling scsi_req_continue will restart I/O.  */
void scsi_req_data(SCSIRequest *req, int len)
{
    trace_scsi_req_data(req->dev->id, req->lun, req->tag, len);
    req->bus->ops->transfer_data(req, len);
}

void scsi_req_print(SCSIRequest *req)
{
    FILE *fp = stderr;
    int i;

    fprintf(fp, "[%s id=%d] %s",
            req->dev->qdev.parent_bus->name,
            req->dev->id,
            scsi_command_name(req->cmd.buf[0]));
    for (i = 1; i < req->cmd.len; i++) {
        fprintf(fp, " 0x%02x", req->cmd.buf[i]);
    }
    switch (req->cmd.mode) {
    case SCSI_XFER_NONE:
        fprintf(fp, " - none\n");
        break;
    case SCSI_XFER_FROM_DEV:
        fprintf(fp, " - from-dev len=%zd\n", req->cmd.xfer);
        break;
    case SCSI_XFER_TO_DEV:
        fprintf(fp, " - to-dev len=%zd\n", req->cmd.xfer);
        break;
    default:
        fprintf(fp, " - Oops\n");
        break;
    }
}

void scsi_req_complete(SCSIRequest *req)
{
    assert(req->status != -1);
    scsi_req_ref(req);
    scsi_req_dequeue(req);
    req->bus->ops->complete(req, req->status);
    scsi_req_unref(req);
}

void scsi_req_cancel(SCSIRequest *req)
{
    if (req->dev && req->dev->info->cancel_io) {
        req->dev->info->cancel_io(req);
    }
    scsi_req_ref(req);
    scsi_req_dequeue(req);
    if (req->bus->ops->cancel) {
        req->bus->ops->cancel(req);
    }
    scsi_req_unref(req);
}

void scsi_req_abort(SCSIRequest *req, int status)
{
    req->status = status;
    if (req->dev && req->dev->info->cancel_io) {
        req->dev->info->cancel_io(req);
    }
    scsi_req_complete(req);
}

void scsi_device_purge_requests(SCSIDevice *sdev)
{
    SCSIRequest *req;

    while (!QTAILQ_EMPTY(&sdev->requests)) {
        req = QTAILQ_FIRST(&sdev->requests);
        scsi_req_cancel(req);
    }
}

static char *scsibus_get_fw_dev_path(DeviceState *dev)
{
    SCSIDevice *d = (SCSIDevice*)dev;
    SCSIBus *bus = scsi_bus_from_device(d);
    char path[100];
    int i;

    for (i = 0; i < bus->ndev; i++) {
        if (bus->devs[i] == d) {
            break;
        }
    }

    assert(i != bus->ndev);

    snprintf(path, sizeof(path), "%s@%x", qdev_fw_name(dev), i);

    return strdup(path);
}