hw/scsi-bus.c

   1 #include "hw.h"
   2 #include "qemu-error.h"
   3 #include "scsi.h"
   4 #include "scsi-defs.h"
   5 #include "qdev.h"
   6 #include "blockdev.h"
   7 #include "trace.h"
   8
   9 static char *scsibus_get_fw_dev_path(DeviceState *dev);
  10
  11 static struct BusInfo scsi_bus_info = {
  12     .name  = "SCSI",
  13     .size  = sizeof(SCSIBus),
  14     .get_fw_dev_path = scsibus_get_fw_dev_path,
  15     .props = (Property[]) {
  16         DEFINE_PROP_UINT32("scsi-id", SCSIDevice, id, -1),
  17         DEFINE_PROP_END_OF_LIST(),
  18     },
  19 };
  20 static int next_scsi_bus;
  21
  22 /* Create a scsi bus, and attach devices to it.  */
  23 void scsi_bus_new(SCSIBus *bus, DeviceState *host, int tcq, int ndev,
  24                   const SCSIBusOps *ops)
  25 {
  26     qbus_create_inplace(&bus->qbus, &scsi_bus_info, host, NULL);
  27     bus->busnr = next_scsi_bus++;
  28     bus->tcq = tcq;
  29     bus->ndev = ndev;
  30     bus->ops = ops;
  31     bus->qbus.allow_hotplug = 1;
  32 }
  33
  34 static int scsi_qdev_init(DeviceState *qdev, DeviceInfo *base)
  35 {
  36     SCSIDevice *dev = DO_UPCAST(SCSIDevice, qdev, qdev);
  37     SCSIDeviceInfo *info = DO_UPCAST(SCSIDeviceInfo, qdev, base);
  38     SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, dev->qdev.parent_bus);
  39     int rc = -1;
  40
  41     if (dev->id == -1) {
  42         for (dev->id = 0; dev->id < bus->ndev; dev->id++) {
  43             if (bus->devs[dev->id] == NULL)
  44                 break;
  45         }
  46     }
  47     if (dev->id >= bus->ndev) {
  48         error_report("bad scsi device id: %d", dev->id);
  49         goto err;
  50     }
  51
  52     if (bus->devs[dev->id]) {
  53         qdev_free(&bus->devs[dev->id]->qdev);
  54     }
  55     bus->devs[dev->id] = dev;
  56
  57     dev->info = info;
  58     QTAILQ_INIT(&dev->requests);
  59     rc = dev->info->init(dev);
  60     if (rc != 0) {
  61         bus->devs[dev->id] = NULL;
  62     }
  63
  64 err:
  65     return rc;
  66 }
  67
  68 static int scsi_qdev_exit(DeviceState *qdev)
  69 {
  70     SCSIDevice *dev = DO_UPCAST(SCSIDevice, qdev, qdev);
  71     SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, dev->qdev.parent_bus);
  72
  73     assert(bus->devs[dev->id] != NULL);
  74     if (bus->devs[dev->id]->info->destroy) {
  75         bus->devs[dev->id]->info->destroy(bus->devs[dev->id]);
  76     }
  77     bus->devs[dev->id] = NULL;
  78     return 0;
  79 }
  80
  81 void scsi_qdev_register(SCSIDeviceInfo *info)
  82 {
  83     info->qdev.bus_info = &scsi_bus_info;
  84     info->qdev.init     = scsi_qdev_init;
  85     info->qdev.unplug   = qdev_simple_unplug_cb;
  86     info->qdev.exit     = scsi_qdev_exit;
  87     qdev_register(&info->qdev);
  88 }
  89
  90 /* handle legacy '-drive if=scsi,...' cmd line args */
  91 SCSIDevice *scsi_bus_legacy_add_drive(SCSIBus *bus, BlockDriverState *bdrv,
  92                                       int unit, bool removable)
  93 {
  94     const char *driver;
  95     DeviceState *dev;
  96
  97     driver = bdrv_is_sg(bdrv) ? "scsi-generic" : "scsi-disk";
  98     dev = qdev_create(&bus->qbus, driver);
  99     qdev_prop_set_uint32(dev, "scsi-id", unit);
 100     if (qdev_prop_exists(dev, "removable")) {
 101         qdev_prop_set_bit(dev, "removable", removable);
 102     }
 103     if (qdev_prop_set_drive(dev, "drive", bdrv) < 0) {
 104         qdev_free(dev);
 105         return NULL;
 106     }
 107     if (qdev_init(dev) < 0)
 108         return NULL;
 109     return DO_UPCAST(SCSIDevice, qdev, dev);
 110 }
 111
 112 int scsi_bus_legacy_handle_cmdline(SCSIBus *bus)
 113 {
 114     Location loc;
 115     DriveInfo *dinfo;
 116     int res = 0, unit;
 117
 118     loc_push_none(&loc);
 119     for (unit = 0; unit < bus->ndev; unit++) {
 120         dinfo = drive_get(IF_SCSI, bus->busnr, unit);
 121         if (dinfo == NULL) {
 122             continue;
 123         }
 124         qemu_opts_loc_restore(dinfo->opts);
 125         if (!scsi_bus_legacy_add_drive(bus, dinfo->bdrv, unit, false)) {
 126             res = -1;
 127             break;
 128         }
 129     }
 130     loc_pop(&loc);
 131     return res;
 132 }
 133
 134 SCSIRequest *scsi_req_alloc(size_t size, SCSIDevice *d, uint32_t tag, uint32_t lun)
 135 {
 136     SCSIRequest *req;
 137
 138     req = qemu_mallocz(size);
 139     req->refcount = 1;
 140     req->bus = scsi_bus_from_device(d);
 141     req->dev = d;
 142     req->tag = tag;
 143     req->lun = lun;
 144     req->status = -1;
 145     trace_scsi_req_alloc(req->dev->id, req->lun, req->tag);
 146     return req;
 147 }
 148
 149 void scsi_req_enqueue(SCSIRequest *req)
 150 {
 151     assert(!req->enqueued);
 152     scsi_req_ref(req);
 153     req->enqueued = true;
 154     QTAILQ_INSERT_TAIL(&req->dev->requests, req, next);
 155 }
 156
 157 void scsi_req_dequeue(SCSIRequest *req)
 158 {
 159     trace_scsi_req_dequeue(req->dev->id, req->lun, req->tag);
 160     if (req->enqueued) {
 161         QTAILQ_REMOVE(&req->dev->requests, req, next);
 162         req->enqueued = false;
 163         scsi_req_unref(req);
 164     }
 165 }
 166
 167 static int scsi_req_length(SCSIRequest *req, uint8_t *cmd)
 168 {
 169     switch (cmd[0] >> 5) {
 170     case 0:
 171         req->cmd.xfer = cmd[4];
 172         req->cmd.len = 6;
 173         /* length 0 means 256 blocks */
 174         if (req->cmd.xfer == 0)
 175             req->cmd.xfer = 256;
 176         break;
 177     case 1:
 178     case 2:
 179         req->cmd.xfer = cmd[8] | (cmd[7] << 8);
 180         req->cmd.len = 10;
 181         break;
 182     case 4:
 183         req->cmd.xfer = cmd[13] | (cmd[12] << 8) | (cmd[11] << 16) | (cmd[10] << 24);
 184         req->cmd.len = 16;
 185         break;
 186     case 5:
 187         req->cmd.xfer = cmd[9] | (cmd[8] << 8) | (cmd[7] << 16) | (cmd[6] << 24);
 188         req->cmd.len = 12;
 189         break;
 190     default:
 191         trace_scsi_req_parse_bad(req->dev->id, req->lun, req->tag, cmd[0]);
 192         return -1;
 193     }
 194
 195     switch(cmd[0]) {
 196     case TEST_UNIT_READY:
 197     case REZERO_UNIT:
 198     case START_STOP:
 199     case SEEK_6:
 200     case WRITE_FILEMARKS:
 201     case SPACE:
 202     case RESERVE:
 203     case RELEASE:
 204     case ERASE:
 205     case ALLOW_MEDIUM_REMOVAL:
 206     case VERIFY:
 207     case SEEK_10:
 208     case SYNCHRONIZE_CACHE:
 209     case LOCK_UNLOCK_CACHE:
 210     case LOAD_UNLOAD:
 211     case SET_CD_SPEED:
 212     case SET_LIMITS:
 213     case WRITE_LONG:
 214     case MOVE_MEDIUM:
 215     case UPDATE_BLOCK:
 216         req->cmd.xfer = 0;
 217         break;
 218     case MODE_SENSE:
 219         break;
 220     case WRITE_SAME:
 221         req->cmd.xfer = 1;
 222         break;
 223     case READ_CAPACITY:
 224         req->cmd.xfer = 8;
 225         break;
 226     case READ_BLOCK_LIMITS:
 227         req->cmd.xfer = 6;
 228         break;
 229     case READ_POSITION:
 230         req->cmd.xfer = 20;
 231         break;
 232     case SEND_VOLUME_TAG:
 233         req->cmd.xfer *= 40;
 234         break;
 235     case MEDIUM_SCAN:
 236         req->cmd.xfer *= 8;
 237         break;
 238     case WRITE_10:
 239     case WRITE_VERIFY:
 240     case WRITE_6:
 241     case WRITE_12:
 242     case WRITE_VERIFY_12:
 243     case WRITE_16:
 244     case WRITE_VERIFY_16:
 245         req->cmd.xfer *= req->dev->blocksize;
 246         break;
 247     case READ_10:
 248     case READ_6:
 249     case READ_REVERSE:
 250     case RECOVER_BUFFERED_DATA:
 251     case READ_12:
 252     case READ_16:
 253         req->cmd.xfer *= req->dev->blocksize;
 254         break;
 255     case INQUIRY:
 256         req->cmd.xfer = cmd[4] | (cmd[3] << 8);
 257         break;
 258     case MAINTENANCE_OUT:
 259     case MAINTENANCE_IN:
 260         if (req->dev->type == TYPE_ROM) {
 261             /* GPCMD_REPORT_KEY and GPCMD_SEND_KEY from multi media commands */
 262             req->cmd.xfer = cmd[9] | (cmd[8] << 8);
 263         }
 264         break;
 265     }
 266     return 0;
 267 }
 268
 269 static int scsi_req_stream_length(SCSIRequest *req, uint8_t *cmd)
 270 {
 271     switch(cmd[0]) {
 272     /* stream commands */
 273     case READ_6:
 274     case READ_REVERSE:
 275     case RECOVER_BUFFERED_DATA:
 276     case WRITE_6:
 277         req->cmd.len = 6;
 278         req->cmd.xfer = cmd[4] | (cmd[3] << 8) | (cmd[2] << 16);
 279         if (cmd[1] & 0x01) /* fixed */
 280             req->cmd.xfer *= req->dev->blocksize;
 281         break;
 282     case REWIND:
 283     case START_STOP:
 284         req->cmd.len = 6;
 285         req->cmd.xfer = 0;
 286         break;
 287     /* generic commands */
 288     default:
 289         return scsi_req_length(req, cmd);
 290     }
 291     return 0;
 292 }
 293
 294 static void scsi_req_xfer_mode(SCSIRequest *req)
 295 {
 296     switch (req->cmd.buf[0]) {
 297     case WRITE_6:
 298     case WRITE_10:
 299     case WRITE_VERIFY:
 300     case WRITE_12:
 301     case WRITE_VERIFY_12:
 302     case WRITE_16:
 303     case WRITE_VERIFY_16:
 304     case COPY:
 305     case COPY_VERIFY:
 306     case COMPARE:
 307     case CHANGE_DEFINITION:
 308     case LOG_SELECT:
 309     case MODE_SELECT:
 310     case MODE_SELECT_10:
 311     case SEND_DIAGNOSTIC:
 312     case WRITE_BUFFER:
 313     case FORMAT_UNIT:
 314     case REASSIGN_BLOCKS:
 315     case SEARCH_EQUAL:
 316     case SEARCH_HIGH:
 317     case SEARCH_LOW:
 318     case UPDATE_BLOCK:
 319     case WRITE_LONG:
 320     case WRITE_SAME:
 321     case SEARCH_HIGH_12:
 322     case SEARCH_EQUAL_12:
 323     case SEARCH_LOW_12:
 324     case SET_WINDOW:
 325     case MEDIUM_SCAN:
 326     case SEND_VOLUME_TAG:
 327     case WRITE_LONG_2:
 328     case PERSISTENT_RESERVE_OUT:
 329     case MAINTENANCE_OUT:
 330         req->cmd.mode = SCSI_XFER_TO_DEV;
 331         break;
 332     default:
 333         if (req->cmd.xfer)
 334             req->cmd.mode = SCSI_XFER_FROM_DEV;
 335         else {
 336             req->cmd.mode = SCSI_XFER_NONE;
 337         }
 338         break;
 339     }
 340 }
 341
 342 static uint64_t scsi_req_lba(SCSIRequest *req)
 343 {
 344     uint8_t *buf = req->cmd.buf;
 345     uint64_t lba;
 346
 347     switch (buf[0] >> 5) {
 348     case 0:
 349         lba = (uint64_t) buf[3] | ((uint64_t) buf[2] << 8) |
 350               (((uint64_t) buf[1] & 0x1f) << 16);
 351         break;
 352     case 1:
 353     case 2:
 354         lba = (uint64_t) buf[5] | ((uint64_t) buf[4] << 8) |
 355               ((uint64_t) buf[3] << 16) | ((uint64_t) buf[2] << 24);
 356         break;
 357     case 4:
 358         lba = (uint64_t) buf[9] | ((uint64_t) buf[8] << 8) |
 359               ((uint64_t) buf[7] << 16) | ((uint64_t) buf[6] << 24) |
 360               ((uint64_t) buf[5] << 32) | ((uint64_t) buf[4] << 40) |
 361               ((uint64_t) buf[3] << 48) | ((uint64_t) buf[2] << 56);
 362         break;
 363     case 5:
 364         lba = (uint64_t) buf[5] | ((uint64_t) buf[4] << 8) |
 365               ((uint64_t) buf[3] << 16) | ((uint64_t) buf[2] << 24);
 366         break;
 367     default:
 368         lba = -1;
 369
 370     }
 371     return lba;
 372 }
 373
 374 int scsi_req_parse(SCSIRequest *req, uint8_t *buf)
 375 {
 376     int rc;
 377
 378     if (req->dev->type == TYPE_TAPE) {
 379         rc = scsi_req_stream_length(req, buf);
 380     } else {
 381         rc = scsi_req_length(req, buf);
 382     }
 383     if (rc != 0)
 384         return rc;
 385
 386     memcpy(req->cmd.buf, buf, req->cmd.len);
 387     scsi_req_xfer_mode(req);
 388     req->cmd.lba = scsi_req_lba(req);
 389     trace_scsi_req_parsed(req->dev->id, req->lun, req->tag, buf[0],
 390                           req->cmd.mode, req->cmd.xfer, req->cmd.lba);
 391     return 0;
 392 }
 393
 394 static const char *scsi_command_name(uint8_t cmd)
 395 {
 396     static const char *names[] = {
 397         [ TEST_UNIT_READY          ] = "TEST_UNIT_READY",
 398         [ REZERO_UNIT              ] = "REZERO_UNIT",
 399         /* REWIND and REZERO_UNIT use the same operation code */
 400         [ REQUEST_SENSE            ] = "REQUEST_SENSE",
 401         [ FORMAT_UNIT              ] = "FORMAT_UNIT",
 402         [ READ_BLOCK_LIMITS        ] = "READ_BLOCK_LIMITS",
 403         [ REASSIGN_BLOCKS          ] = "REASSIGN_BLOCKS",
 404         [ READ_6                   ] = "READ_6",
 405         [ WRITE_6                  ] = "WRITE_6",
 406         [ SEEK_6                   ] = "SEEK_6",
 407         [ READ_REVERSE             ] = "READ_REVERSE",
 408         [ WRITE_FILEMARKS          ] = "WRITE_FILEMARKS",
 409         [ SPACE                    ] = "SPACE",
 410         [ INQUIRY                  ] = "INQUIRY",
 411         [ RECOVER_BUFFERED_DATA    ] = "RECOVER_BUFFERED_DATA",
 412         [ MAINTENANCE_IN           ] = "MAINTENANCE_IN",
 413         [ MAINTENANCE_OUT          ] = "MAINTENANCE_OUT",
 414         [ MODE_SELECT              ] = "MODE_SELECT",
 415         [ RESERVE                  ] = "RESERVE",
 416         [ RELEASE                  ] = "RELEASE",
 417         [ COPY                     ] = "COPY",
 418         [ ERASE                    ] = "ERASE",
 419         [ MODE_SENSE               ] = "MODE_SENSE",
 420         [ START_STOP               ] = "START_STOP",
 421         [ RECEIVE_DIAGNOSTIC       ] = "RECEIVE_DIAGNOSTIC",
 422         [ SEND_DIAGNOSTIC          ] = "SEND_DIAGNOSTIC",
 423         [ ALLOW_MEDIUM_REMOVAL     ] = "ALLOW_MEDIUM_REMOVAL",
 424
 425         [ SET_WINDOW               ] = "SET_WINDOW",
 426         [ READ_CAPACITY            ] = "READ_CAPACITY",
 427         [ READ_10                  ] = "READ_10",
 428         [ WRITE_10                 ] = "WRITE_10",
 429         [ SEEK_10                  ] = "SEEK_10",
 430         [ WRITE_VERIFY             ] = "WRITE_VERIFY",
 431         [ VERIFY                   ] = "VERIFY",
 432         [ SEARCH_HIGH              ] = "SEARCH_HIGH",
 433         [ SEARCH_EQUAL             ] = "SEARCH_EQUAL",
 434         [ SEARCH_LOW               ] = "SEARCH_LOW",
 435         [ SET_LIMITS               ] = "SET_LIMITS",
 436         [ PRE_FETCH                ] = "PRE_FETCH",
 437         /* READ_POSITION and PRE_FETCH use the same operation code */
 438         [ SYNCHRONIZE_CACHE        ] = "SYNCHRONIZE_CACHE",
 439         [ LOCK_UNLOCK_CACHE        ] = "LOCK_UNLOCK_CACHE",
 440         [ READ_DEFECT_DATA         ] = "READ_DEFECT_DATA",
 441         [ MEDIUM_SCAN              ] = "MEDIUM_SCAN",
 442         [ COMPARE                  ] = "COMPARE",
 443         [ COPY_VERIFY              ] = "COPY_VERIFY",
 444         [ WRITE_BUFFER             ] = "WRITE_BUFFER",
 445         [ READ_BUFFER              ] = "READ_BUFFER",
 446         [ UPDATE_BLOCK             ] = "UPDATE_BLOCK",
 447         [ READ_LONG                ] = "READ_LONG",
 448         [ WRITE_LONG               ] = "WRITE_LONG",
 449         [ CHANGE_DEFINITION        ] = "CHANGE_DEFINITION",
 450         [ WRITE_SAME               ] = "WRITE_SAME",
 451         [ READ_TOC                 ] = "READ_TOC",
 452         [ LOG_SELECT               ] = "LOG_SELECT",
 453         [ LOG_SENSE                ] = "LOG_SENSE",
 454         [ MODE_SELECT_10           ] = "MODE_SELECT_10",
 455         [ RESERVE_10               ] = "RESERVE_10",
 456         [ RELEASE_10               ] = "RELEASE_10",
 457         [ MODE_SENSE_10            ] = "MODE_SENSE_10",
 458         [ PERSISTENT_RESERVE_IN    ] = "PERSISTENT_RESERVE_IN",
 459         [ PERSISTENT_RESERVE_OUT   ] = "PERSISTENT_RESERVE_OUT",
 460         [ MOVE_MEDIUM              ] = "MOVE_MEDIUM",
 461         [ READ_12                  ] = "READ_12",
 462         [ WRITE_12                 ] = "WRITE_12",
 463         [ WRITE_VERIFY_12          ] = "WRITE_VERIFY_12",
 464         [ SEARCH_HIGH_12           ] = "SEARCH_HIGH_12",
 465         [ SEARCH_EQUAL_12          ] = "SEARCH_EQUAL_12",
 466         [ SEARCH_LOW_12            ] = "SEARCH_LOW_12",
 467         [ READ_ELEMENT_STATUS      ] = "READ_ELEMENT_STATUS",
 468         [ SEND_VOLUME_TAG          ] = "SEND_VOLUME_TAG",
 469         [ WRITE_LONG_2             ] = "WRITE_LONG_2",
 470
 471         [ REPORT_DENSITY_SUPPORT   ] = "REPORT_DENSITY_SUPPORT",
 472         [ GET_CONFIGURATION        ] = "GET_CONFIGURATION",
 473         [ READ_16                  ] = "READ_16",
 474         [ WRITE_16                 ] = "WRITE_16",
 475         [ WRITE_VERIFY_16          ] = "WRITE_VERIFY_16",
 476         [ SERVICE_ACTION_IN        ] = "SERVICE_ACTION_IN",
 477         [ REPORT_LUNS              ] = "REPORT_LUNS",
 478         [ LOAD_UNLOAD              ] = "LOAD_UNLOAD",
 479         [ SET_CD_SPEED             ] = "SET_CD_SPEED",
 480         [ BLANK                    ] = "BLANK",
 481     };
 482
 483     if (cmd >= ARRAY_SIZE(names) || names[cmd] == NULL)
 484         return "*UNKNOWN*";
 485     return names[cmd];
 486 }
 487
 488 SCSIRequest *scsi_req_ref(SCSIRequest *req)
 489 {
 490     req->refcount++;
 491     return req;
 492 }
 493
 494 void scsi_req_unref(SCSIRequest *req)
 495 {
 496     if (--req->refcount == 0) {
 497         if (req->dev->info->free_req) {
 498             req->dev->info->free_req(req);
 499         }
 500         qemu_free(req);
 501     }
 502 }
 503
 504 /* Called by the devices when data is ready for the HBA.  The HBA should
 505    start a DMA operation to read or fill the device's data buffer.
 506    Once it completes, calling one of req->dev->info->read_data or
 507    req->dev->info->write_data (depending on the direction of the
 508    transfer) will restart I/O.  */
 509 void scsi_req_data(SCSIRequest *req, int len)
 510 {
 511     trace_scsi_req_data(req->dev->id, req->lun, req->tag, len);
 512     req->bus->ops->complete(req, SCSI_REASON_DATA, len);
 513 }
 514
 515 void scsi_req_print(SCSIRequest *req)
 516 {
 517     FILE *fp = stderr;
 518     int i;
 519
 520     fprintf(fp, "[%s id=%d] %s",
 521             req->dev->qdev.parent_bus->name,
 522             req->dev->id,
 523             scsi_command_name(req->cmd.buf[0]));
 524     for (i = 1; i < req->cmd.len; i++) {
 525         fprintf(fp, " 0x%02x", req->cmd.buf[i]);
 526     }
 527     switch (req->cmd.mode) {
 528     case SCSI_XFER_NONE:
 529         fprintf(fp, " - none\n");
 530         break;
 531     case SCSI_XFER_FROM_DEV:
 532         fprintf(fp, " - from-dev len=%zd\n", req->cmd.xfer);
 533         break;
 534     case SCSI_XFER_TO_DEV:
 535         fprintf(fp, " - to-dev len=%zd\n", req->cmd.xfer);
 536         break;
 537     default:
 538         fprintf(fp, " - Oops\n");
 539         break;
 540     }
 541 }
 542
 543 void scsi_req_complete(SCSIRequest *req)
 544 {
 545     assert(req->status != -1);
 546     scsi_req_ref(req);
 547     scsi_req_dequeue(req);
 548     req->bus->ops->complete(req, SCSI_REASON_DONE, req->status);
 549     scsi_req_unref(req);
 550 }
 551
 552 void scsi_req_cancel(SCSIRequest *req)
 553 {
 554     if (req->dev && req->dev->info->cancel_io) {
 555         req->dev->info->cancel_io(req);
 556     }
 557     scsi_req_ref(req);
 558     scsi_req_dequeue(req);
 559     if (req->bus->ops->cancel) {
 560         req->bus->ops->cancel(req);
 561     }
 562     scsi_req_unref(req);
 563 }
 564
 565 void scsi_req_abort(SCSIRequest *req, int status)
 566 {
 567     req->status = status;
 568     if (req->dev && req->dev->info->cancel_io) {
 569         req->dev->info->cancel_io(req);
 570     }
 571     scsi_req_complete(req);
 572 }
 573
 574 void scsi_device_purge_requests(SCSIDevice *sdev)
 575 {
 576     SCSIRequest *req;
 577
 578     while (!QTAILQ_EMPTY(&sdev->requests)) {
 579         req = QTAILQ_FIRST(&sdev->requests);
 580         scsi_req_cancel(req);
 581     }
 582 }
 583
 584 static char *scsibus_get_fw_dev_path(DeviceState *dev)
 585 {
 586     SCSIDevice *d = (SCSIDevice*)dev;
 587     SCSIBus *bus = scsi_bus_from_device(d);
 588     char path[100];
 589     int i;
 590
 591     for (i = 0; i < bus->ndev; i++) {
 592         if (bus->devs[i] == d) {
 593             break;
 594         }
 595     }
 596
 597     assert(i != bus->ndev);
 598
 599     snprintf(path, sizeof(path), "%s@%x", qdev_fw_name(dev), i);
 600
 601     return strdup(path);
 602 }