xref: /openbmc/qemu/hw/scsi/scsi-bus.c (revision 1098cc3f)
1 #include "qemu/osdep.h"
2 #include "qapi/error.h"
3 #include "qemu/error-report.h"
4 #include "qemu/module.h"
5 #include "qemu/option.h"
6 #include "qemu/hw-version.h"
7 #include "hw/qdev-properties.h"
8 #include "hw/scsi/scsi.h"
9 #include "migration/qemu-file-types.h"
10 #include "migration/vmstate.h"
11 #include "scsi/constants.h"
12 #include "sysemu/block-backend.h"
13 #include "sysemu/blockdev.h"
14 #include "sysemu/sysemu.h"
15 #include "sysemu/runstate.h"
16 #include "trace.h"
17 #include "sysemu/dma.h"
18 #include "qemu/cutils.h"
19 
20 static char *scsibus_get_dev_path(DeviceState *dev);
21 static char *scsibus_get_fw_dev_path(DeviceState *dev);
22 static void scsi_req_dequeue(SCSIRequest *req);
23 static uint8_t *scsi_target_alloc_buf(SCSIRequest *req, size_t len);
24 static void scsi_target_free_buf(SCSIRequest *req);
25 
26 static int next_scsi_bus;
27 
28 static SCSIDevice *do_scsi_device_find(SCSIBus *bus,
29                                        int channel, int id, int lun,
30                                        bool include_unrealized)
31 {
32     BusChild *kid;
33     SCSIDevice *retval = NULL;
34 
35     QTAILQ_FOREACH_RCU(kid, &bus->qbus.children, sibling) {
36         DeviceState *qdev = kid->child;
37         SCSIDevice *dev = SCSI_DEVICE(qdev);
38 
39         if (dev->channel == channel && dev->id == id) {
40             if (dev->lun == lun) {
41                 retval = dev;
42                 break;
43             }
44 
45             /*
46              * If we don't find exact match (channel/bus/lun),
47              * we will return the first device which matches channel/bus
48              */
49 
50             if (!retval) {
51                 retval = dev;
52             }
53         }
54     }
55 
56     /*
57      * This function might run on the IO thread and we might race against
58      * main thread hot-plugging the device.
59      * We assume that as soon as .realized is set to true we can let
60      * the user access the device.
61      */
62 
63     if (retval && !include_unrealized &&
64         !qatomic_load_acquire(&retval->qdev.realized)) {
65         retval = NULL;
66     }
67 
68     return retval;
69 }
70 
71 SCSIDevice *scsi_device_find(SCSIBus *bus, int channel, int id, int lun)
72 {
73     RCU_READ_LOCK_GUARD();
74     return do_scsi_device_find(bus, channel, id, lun, false);
75 }
76 
77 SCSIDevice *scsi_device_get(SCSIBus *bus, int channel, int id, int lun)
78 {
79     SCSIDevice *d;
80     RCU_READ_LOCK_GUARD();
81     d = do_scsi_device_find(bus, channel, id, lun, false);
82     if (d) {
83         object_ref(d);
84     }
85     return d;
86 }
87 
88 static void scsi_device_realize(SCSIDevice *s, Error **errp)
89 {
90     SCSIDeviceClass *sc = SCSI_DEVICE_GET_CLASS(s);
91     if (sc->realize) {
92         sc->realize(s, errp);
93     }
94 }
95 
96 static void scsi_device_unrealize(SCSIDevice *s)
97 {
98     SCSIDeviceClass *sc = SCSI_DEVICE_GET_CLASS(s);
99     if (sc->unrealize) {
100         sc->unrealize(s);
101     }
102 }
103 
104 int scsi_bus_parse_cdb(SCSIDevice *dev, SCSICommand *cmd, uint8_t *buf,
105                        size_t buf_len, void *hba_private)
106 {
107     SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, dev->qdev.parent_bus);
108     int rc;
109 
110     assert(cmd->len == 0);
111     rc = scsi_req_parse_cdb(dev, cmd, buf, buf_len);
112     if (bus->info->parse_cdb) {
113         rc = bus->info->parse_cdb(dev, cmd, buf, buf_len, hba_private);
114     }
115     return rc;
116 }
117 
118 static SCSIRequest *scsi_device_alloc_req(SCSIDevice *s, uint32_t tag, uint32_t lun,
119                                           uint8_t *buf, void *hba_private)
120 {
121     SCSIDeviceClass *sc = SCSI_DEVICE_GET_CLASS(s);
122     if (sc->alloc_req) {
123         return sc->alloc_req(s, tag, lun, buf, hba_private);
124     }
125 
126     return NULL;
127 }
128 
129 void scsi_device_unit_attention_reported(SCSIDevice *s)
130 {
131     SCSIDeviceClass *sc = SCSI_DEVICE_GET_CLASS(s);
132     if (sc->unit_attention_reported) {
133         sc->unit_attention_reported(s);
134     }
135 }
136 
137 /* Create a scsi bus, and attach devices to it.  */
138 void scsi_bus_init_named(SCSIBus *bus, size_t bus_size, DeviceState *host,
139                          const SCSIBusInfo *info, const char *bus_name)
140 {
141     qbus_init(bus, bus_size, TYPE_SCSI_BUS, host, bus_name);
142     bus->busnr = next_scsi_bus++;
143     bus->info = info;
144     qbus_set_bus_hotplug_handler(BUS(bus));
145 }
146 
147 static void scsi_dma_restart_bh(void *opaque)
148 {
149     SCSIDevice *s = opaque;
150     SCSIRequest *req, *next;
151 
152     qemu_bh_delete(s->bh);
153     s->bh = NULL;
154 
155     aio_context_acquire(blk_get_aio_context(s->conf.blk));
156     QTAILQ_FOREACH_SAFE(req, &s->requests, next, next) {
157         scsi_req_ref(req);
158         if (req->retry) {
159             req->retry = false;
160             switch (req->cmd.mode) {
161             case SCSI_XFER_FROM_DEV:
162             case SCSI_XFER_TO_DEV:
163                 scsi_req_continue(req);
164                 break;
165             case SCSI_XFER_NONE:
166                 scsi_req_dequeue(req);
167                 scsi_req_enqueue(req);
168                 break;
169             }
170         }
171         scsi_req_unref(req);
172     }
173     aio_context_release(blk_get_aio_context(s->conf.blk));
174     /* Drop the reference that was acquired in scsi_dma_restart_cb */
175     object_unref(OBJECT(s));
176 }
177 
178 void scsi_req_retry(SCSIRequest *req)
179 {
180     /* No need to save a reference, because scsi_dma_restart_bh just
181      * looks at the request list.  */
182     req->retry = true;
183 }
184 
185 static void scsi_dma_restart_cb(void *opaque, bool running, RunState state)
186 {
187     SCSIDevice *s = opaque;
188 
189     if (!running) {
190         return;
191     }
192     if (!s->bh) {
193         AioContext *ctx = blk_get_aio_context(s->conf.blk);
194         /* The reference is dropped in scsi_dma_restart_bh.*/
195         object_ref(OBJECT(s));
196         s->bh = aio_bh_new_guarded(ctx, scsi_dma_restart_bh, s,
197                                    &DEVICE(s)->mem_reentrancy_guard);
198         qemu_bh_schedule(s->bh);
199     }
200 }
201 
202 static bool scsi_bus_is_address_free(SCSIBus *bus,
203                                      int channel, int target, int lun,
204                                      SCSIDevice **p_dev)
205 {
206     SCSIDevice *d;
207 
208     RCU_READ_LOCK_GUARD();
209     d = do_scsi_device_find(bus, channel, target, lun, true);
210     if (d && d->lun == lun) {
211         if (p_dev) {
212             *p_dev = d;
213         }
214         return false;
215     }
216     if (p_dev) {
217         *p_dev = NULL;
218     }
219     return true;
220 }
221 
222 static bool scsi_bus_check_address(BusState *qbus, DeviceState *qdev, Error **errp)
223 {
224     SCSIDevice *dev = SCSI_DEVICE(qdev);
225     SCSIBus *bus = SCSI_BUS(qbus);
226 
227     if (dev->channel > bus->info->max_channel) {
228         error_setg(errp, "bad scsi channel id: %d", dev->channel);
229         return false;
230     }
231     if (dev->id != -1 && dev->id > bus->info->max_target) {
232         error_setg(errp, "bad scsi device id: %d", dev->id);
233         return false;
234     }
235     if (dev->lun != -1 && dev->lun > bus->info->max_lun) {
236         error_setg(errp, "bad scsi device lun: %d", dev->lun);
237         return false;
238     }
239 
240     if (dev->id != -1 && dev->lun != -1) {
241         SCSIDevice *d;
242         if (!scsi_bus_is_address_free(bus, dev->channel, dev->id, dev->lun, &d)) {
243             error_setg(errp, "lun already used by '%s'", d->qdev.id);
244             return false;
245         }
246     }
247 
248     return true;
249 }
250 
251 static void scsi_qdev_realize(DeviceState *qdev, Error **errp)
252 {
253     SCSIDevice *dev = SCSI_DEVICE(qdev);
254     SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, dev->qdev.parent_bus);
255     bool is_free;
256     Error *local_err = NULL;
257 
258     if (dev->id == -1) {
259         int id = -1;
260         if (dev->lun == -1) {
261             dev->lun = 0;
262         }
263         do {
264             is_free = scsi_bus_is_address_free(bus, dev->channel, ++id, dev->lun, NULL);
265         } while (!is_free && id < bus->info->max_target);
266         if (!is_free) {
267             error_setg(errp, "no free target");
268             return;
269         }
270         dev->id = id;
271     } else if (dev->lun == -1) {
272         int lun = -1;
273         do {
274             is_free = scsi_bus_is_address_free(bus, dev->channel, dev->id, ++lun, NULL);
275         } while (!is_free && lun < bus->info->max_lun);
276         if (!is_free) {
277             error_setg(errp, "no free lun");
278             return;
279         }
280         dev->lun = lun;
281     }
282 
283     QTAILQ_INIT(&dev->requests);
284     scsi_device_realize(dev, &local_err);
285     if (local_err) {
286         error_propagate(errp, local_err);
287         return;
288     }
289     dev->vmsentry = qdev_add_vm_change_state_handler(DEVICE(dev),
290             scsi_dma_restart_cb, dev);
291 }
292 
293 static void scsi_qdev_unrealize(DeviceState *qdev)
294 {
295     SCSIDevice *dev = SCSI_DEVICE(qdev);
296 
297     if (dev->vmsentry) {
298         qemu_del_vm_change_state_handler(dev->vmsentry);
299     }
300 
301     scsi_device_purge_requests(dev, SENSE_CODE(NO_SENSE));
302 
303     scsi_device_unrealize(dev);
304 
305     blockdev_mark_auto_del(dev->conf.blk);
306 }
307 
308 /* handle legacy '-drive if=scsi,...' cmd line args */
309 SCSIDevice *scsi_bus_legacy_add_drive(SCSIBus *bus, BlockBackend *blk,
310                                       int unit, bool removable, int bootindex,
311                                       bool share_rw,
312                                       BlockdevOnError rerror,
313                                       BlockdevOnError werror,
314                                       const char *serial, Error **errp)
315 {
316     const char *driver;
317     char *name;
318     DeviceState *dev;
319     DriveInfo *dinfo;
320 
321     if (blk_is_sg(blk)) {
322         driver = "scsi-generic";
323     } else {
324         dinfo = blk_legacy_dinfo(blk);
325         if (dinfo && dinfo->media_cd) {
326             driver = "scsi-cd";
327         } else {
328             driver = "scsi-hd";
329         }
330     }
331     dev = qdev_new(driver);
332     name = g_strdup_printf("legacy[%d]", unit);
333     object_property_add_child(OBJECT(bus), name, OBJECT(dev));
334     g_free(name);
335 
336     qdev_prop_set_uint32(dev, "scsi-id", unit);
337     if (bootindex >= 0) {
338         object_property_set_int(OBJECT(dev), "bootindex", bootindex,
339                                 &error_abort);
340     }
341     if (object_property_find(OBJECT(dev), "removable")) {
342         qdev_prop_set_bit(dev, "removable", removable);
343     }
344     if (serial && object_property_find(OBJECT(dev), "serial")) {
345         qdev_prop_set_string(dev, "serial", serial);
346     }
347     if (!qdev_prop_set_drive_err(dev, "drive", blk, errp)) {
348         object_unparent(OBJECT(dev));
349         return NULL;
350     }
351     if (!object_property_set_bool(OBJECT(dev), "share-rw", share_rw, errp)) {
352         object_unparent(OBJECT(dev));
353         return NULL;
354     }
355 
356     qdev_prop_set_enum(dev, "rerror", rerror);
357     qdev_prop_set_enum(dev, "werror", werror);
358 
359     if (!qdev_realize_and_unref(dev, &bus->qbus, errp)) {
360         object_unparent(OBJECT(dev));
361         return NULL;
362     }
363     return SCSI_DEVICE(dev);
364 }
365 
366 void scsi_bus_legacy_handle_cmdline(SCSIBus *bus)
367 {
368     Location loc;
369     DriveInfo *dinfo;
370     int unit;
371 
372     loc_push_none(&loc);
373     for (unit = 0; unit <= bus->info->max_target; unit++) {
374         dinfo = drive_get(IF_SCSI, bus->busnr, unit);
375         if (dinfo == NULL) {
376             continue;
377         }
378         qemu_opts_loc_restore(dinfo->opts);
379         scsi_bus_legacy_add_drive(bus, blk_by_legacy_dinfo(dinfo),
380                                   unit, false, -1, false,
381                                   BLOCKDEV_ON_ERROR_AUTO,
382                                   BLOCKDEV_ON_ERROR_AUTO,
383                                   NULL, &error_fatal);
384     }
385     loc_pop(&loc);
386 }
387 
388 static int32_t scsi_invalid_field(SCSIRequest *req, uint8_t *buf)
389 {
390     scsi_req_build_sense(req, SENSE_CODE(INVALID_FIELD));
391     scsi_req_complete(req, CHECK_CONDITION);
392     return 0;
393 }
394 
395 static const struct SCSIReqOps reqops_invalid_field = {
396     .size         = sizeof(SCSIRequest),
397     .send_command = scsi_invalid_field
398 };
399 
400 /* SCSIReqOps implementation for invalid commands.  */
401 
402 static int32_t scsi_invalid_command(SCSIRequest *req, uint8_t *buf)
403 {
404     scsi_req_build_sense(req, SENSE_CODE(INVALID_OPCODE));
405     scsi_req_complete(req, CHECK_CONDITION);
406     return 0;
407 }
408 
409 static const struct SCSIReqOps reqops_invalid_opcode = {
410     .size         = sizeof(SCSIRequest),
411     .send_command = scsi_invalid_command
412 };
413 
414 /* SCSIReqOps implementation for unit attention conditions.  */
415 
416 static int32_t scsi_unit_attention(SCSIRequest *req, uint8_t *buf)
417 {
418     if (req->dev->unit_attention.key == UNIT_ATTENTION) {
419         scsi_req_build_sense(req, req->dev->unit_attention);
420     } else if (req->bus->unit_attention.key == UNIT_ATTENTION) {
421         scsi_req_build_sense(req, req->bus->unit_attention);
422     }
423     scsi_req_complete(req, CHECK_CONDITION);
424     return 0;
425 }
426 
427 static const struct SCSIReqOps reqops_unit_attention = {
428     .size         = sizeof(SCSIRequest),
429     .send_command = scsi_unit_attention
430 };
431 
432 /* SCSIReqOps implementation for REPORT LUNS and for commands sent to
433    an invalid LUN.  */
434 
435 typedef struct SCSITargetReq SCSITargetReq;
436 
437 struct SCSITargetReq {
438     SCSIRequest req;
439     int len;
440     uint8_t *buf;
441     int buf_len;
442 };
443 
444 static void store_lun(uint8_t *outbuf, int lun)
445 {
446     if (lun < 256) {
447         /* Simple logical unit addressing method*/
448         outbuf[0] = 0;
449         outbuf[1] = lun;
450     } else {
451         /* Flat space addressing method */
452         outbuf[0] = 0x40 | (lun >> 8);
453         outbuf[1] = (lun & 255);
454     }
455 }
456 
457 static bool scsi_target_emulate_report_luns(SCSITargetReq *r)
458 {
459     BusChild *kid;
460     int channel, id;
461     uint8_t tmp[8] = {0};
462     int len = 0;
463     GByteArray *buf;
464 
465     if (r->req.cmd.xfer < 16) {
466         return false;
467     }
468     if (r->req.cmd.buf[2] > 2) {
469         return false;
470     }
471 
472     /* reserve space for 63 LUNs*/
473     buf = g_byte_array_sized_new(512);
474 
475     channel = r->req.dev->channel;
476     id = r->req.dev->id;
477 
478     /* add size (will be updated later to correct value */
479     g_byte_array_append(buf, tmp, 8);
480     len += 8;
481 
482     /* add LUN0 */
483     g_byte_array_append(buf, tmp, 8);
484     len += 8;
485 
486     WITH_RCU_READ_LOCK_GUARD() {
487         QTAILQ_FOREACH_RCU(kid, &r->req.bus->qbus.children, sibling) {
488             DeviceState *qdev = kid->child;
489             SCSIDevice *dev = SCSI_DEVICE(qdev);
490 
491             if (dev->channel == channel && dev->id == id && dev->lun != 0) {
492                 store_lun(tmp, dev->lun);
493                 g_byte_array_append(buf, tmp, 8);
494                 len += 8;
495             }
496         }
497     }
498 
499     r->buf_len = len;
500     r->buf = g_byte_array_free(buf, FALSE);
501     r->len = MIN(len, r->req.cmd.xfer & ~7);
502 
503     /* store the LUN list length */
504     stl_be_p(&r->buf[0], len - 8);
505     return true;
506 }
507 
508 static bool scsi_target_emulate_inquiry(SCSITargetReq *r)
509 {
510     assert(r->req.dev->lun != r->req.lun);
511 
512     scsi_target_alloc_buf(&r->req, SCSI_INQUIRY_LEN);
513 
514     if (r->req.cmd.buf[1] & 0x2) {
515         /* Command support data - optional, not implemented */
516         return false;
517     }
518 
519     if (r->req.cmd.buf[1] & 0x1) {
520         /* Vital product data */
521         uint8_t page_code = r->req.cmd.buf[2];
522         r->buf[r->len++] = page_code ; /* this page */
523         r->buf[r->len++] = 0x00;
524 
525         switch (page_code) {
526         case 0x00: /* Supported page codes, mandatory */
527         {
528             int pages;
529             pages = r->len++;
530             r->buf[r->len++] = 0x00; /* list of supported pages (this page) */
531             r->buf[pages] = r->len - pages - 1; /* number of pages */
532             break;
533         }
534         default:
535             return false;
536         }
537         /* done with EVPD */
538         assert(r->len < r->buf_len);
539         r->len = MIN(r->req.cmd.xfer, r->len);
540         return true;
541     }
542 
543     /* Standard INQUIRY data */
544     if (r->req.cmd.buf[2] != 0) {
545         return false;
546     }
547 
548     /* PAGE CODE == 0 */
549     r->len = MIN(r->req.cmd.xfer, SCSI_INQUIRY_LEN);
550     memset(r->buf, 0, r->len);
551     if (r->req.lun != 0) {
552         r->buf[0] = TYPE_NO_LUN;
553     } else {
554         r->buf[0] = TYPE_NOT_PRESENT | TYPE_INACTIVE;
555         r->buf[2] = 5; /* Version */
556         r->buf[3] = 2 | 0x10; /* HiSup, response data format */
557         r->buf[4] = r->len - 5; /* Additional Length = (Len - 1) - 4 */
558         r->buf[7] = 0x10 | (r->req.bus->info->tcq ? 0x02 : 0); /* Sync, TCQ.  */
559         memcpy(&r->buf[8], "QEMU    ", 8);
560         memcpy(&r->buf[16], "QEMU TARGET     ", 16);
561         pstrcpy((char *) &r->buf[32], 4, qemu_hw_version());
562     }
563     return true;
564 }
565 
566 static size_t scsi_sense_len(SCSIRequest *req)
567 {
568     if (req->dev->type == TYPE_SCANNER)
569         return SCSI_SENSE_LEN_SCANNER;
570     else
571         return SCSI_SENSE_LEN;
572 }
573 
574 static int32_t scsi_target_send_command(SCSIRequest *req, uint8_t *buf)
575 {
576     SCSITargetReq *r = DO_UPCAST(SCSITargetReq, req, req);
577     int fixed_sense = (req->cmd.buf[1] & 1) == 0;
578 
579     if (req->lun != 0 &&
580         buf[0] != INQUIRY && buf[0] != REQUEST_SENSE) {
581         scsi_req_build_sense(req, SENSE_CODE(LUN_NOT_SUPPORTED));
582         scsi_req_complete(req, CHECK_CONDITION);
583         return 0;
584     }
585     switch (buf[0]) {
586     case REPORT_LUNS:
587         if (!scsi_target_emulate_report_luns(r)) {
588             goto illegal_request;
589         }
590         break;
591     case INQUIRY:
592         if (!scsi_target_emulate_inquiry(r)) {
593             goto illegal_request;
594         }
595         break;
596     case REQUEST_SENSE:
597         scsi_target_alloc_buf(&r->req, scsi_sense_len(req));
598         if (req->lun != 0) {
599             const struct SCSISense sense = SENSE_CODE(LUN_NOT_SUPPORTED);
600 
601             r->len = scsi_build_sense_buf(r->buf, req->cmd.xfer,
602                                           sense, fixed_sense);
603         } else {
604             r->len = scsi_device_get_sense(r->req.dev, r->buf,
605                                            MIN(req->cmd.xfer, r->buf_len),
606                                            fixed_sense);
607         }
608         if (r->req.dev->sense_is_ua) {
609             scsi_device_unit_attention_reported(req->dev);
610             r->req.dev->sense_len = 0;
611             r->req.dev->sense_is_ua = false;
612         }
613         break;
614     case TEST_UNIT_READY:
615         break;
616     default:
617         scsi_req_build_sense(req, SENSE_CODE(INVALID_OPCODE));
618         scsi_req_complete(req, CHECK_CONDITION);
619         return 0;
620     illegal_request:
621         scsi_req_build_sense(req, SENSE_CODE(INVALID_FIELD));
622         scsi_req_complete(req, CHECK_CONDITION);
623         return 0;
624     }
625 
626     if (!r->len) {
627         scsi_req_complete(req, GOOD);
628     }
629     return r->len;
630 }
631 
632 static void scsi_target_read_data(SCSIRequest *req)
633 {
634     SCSITargetReq *r = DO_UPCAST(SCSITargetReq, req, req);
635     uint32_t n;
636 
637     n = r->len;
638     if (n > 0) {
639         r->len = 0;
640         scsi_req_data(&r->req, n);
641     } else {
642         scsi_req_complete(&r->req, GOOD);
643     }
644 }
645 
646 static uint8_t *scsi_target_get_buf(SCSIRequest *req)
647 {
648     SCSITargetReq *r = DO_UPCAST(SCSITargetReq, req, req);
649 
650     return r->buf;
651 }
652 
653 static uint8_t *scsi_target_alloc_buf(SCSIRequest *req, size_t len)
654 {
655     SCSITargetReq *r = DO_UPCAST(SCSITargetReq, req, req);
656 
657     r->buf = g_malloc(len);
658     r->buf_len = len;
659 
660     return r->buf;
661 }
662 
663 static void scsi_target_free_buf(SCSIRequest *req)
664 {
665     SCSITargetReq *r = DO_UPCAST(SCSITargetReq, req, req);
666 
667     g_free(r->buf);
668 }
669 
670 static const struct SCSIReqOps reqops_target_command = {
671     .size         = sizeof(SCSITargetReq),
672     .send_command = scsi_target_send_command,
673     .read_data    = scsi_target_read_data,
674     .get_buf      = scsi_target_get_buf,
675     .free_req     = scsi_target_free_buf,
676 };
677 
678 
679 SCSIRequest *scsi_req_alloc(const SCSIReqOps *reqops, SCSIDevice *d,
680                             uint32_t tag, uint32_t lun, void *hba_private)
681 {
682     SCSIRequest *req;
683     SCSIBus *bus = scsi_bus_from_device(d);
684     BusState *qbus = BUS(bus);
685     const int memset_off = offsetof(SCSIRequest, sense)
686                            + sizeof(req->sense);
687 
688     req = g_malloc(reqops->size);
689     memset((uint8_t *)req + memset_off, 0, reqops->size - memset_off);
690     req->refcount = 1;
691     req->bus = bus;
692     req->dev = d;
693     req->tag = tag;
694     req->lun = lun;
695     req->hba_private = hba_private;
696     req->status = -1;
697     req->host_status = -1;
698     req->ops = reqops;
699     object_ref(OBJECT(d));
700     object_ref(OBJECT(qbus->parent));
701     notifier_list_init(&req->cancel_notifiers);
702     trace_scsi_req_alloc(req->dev->id, req->lun, req->tag);
703     return req;
704 }
705 
706 SCSIRequest *scsi_req_new(SCSIDevice *d, uint32_t tag, uint32_t lun,
707                           uint8_t *buf, size_t buf_len, void *hba_private)
708 {
709     SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, d->qdev.parent_bus);
710     const SCSIReqOps *ops;
711     SCSIDeviceClass *sc = SCSI_DEVICE_GET_CLASS(d);
712     SCSIRequest *req;
713     SCSICommand cmd = { .len = 0 };
714     int ret;
715 
716     if (buf_len == 0) {
717         trace_scsi_req_parse_bad(d->id, lun, tag, 0);
718         goto invalid_opcode;
719     }
720 
721     if ((d->unit_attention.key == UNIT_ATTENTION ||
722          bus->unit_attention.key == UNIT_ATTENTION) &&
723         (buf[0] != INQUIRY &&
724          buf[0] != REPORT_LUNS &&
725          buf[0] != GET_CONFIGURATION &&
726          buf[0] != GET_EVENT_STATUS_NOTIFICATION &&
727 
728          /*
729           * If we already have a pending unit attention condition,
730           * report this one before triggering another one.
731           */
732          !(buf[0] == REQUEST_SENSE && d->sense_is_ua))) {
733         ops = &reqops_unit_attention;
734     } else if (lun != d->lun ||
735                buf[0] == REPORT_LUNS ||
736                (buf[0] == REQUEST_SENSE && d->sense_len)) {
737         ops = &reqops_target_command;
738     } else {
739         ops = NULL;
740     }
741 
742     if (ops != NULL || !sc->parse_cdb) {
743         ret = scsi_req_parse_cdb(d, &cmd, buf, buf_len);
744     } else {
745         ret = sc->parse_cdb(d, &cmd, buf, buf_len, hba_private);
746     }
747 
748     if (ret != 0) {
749         trace_scsi_req_parse_bad(d->id, lun, tag, buf[0]);
750 invalid_opcode:
751         req = scsi_req_alloc(&reqops_invalid_opcode, d, tag, lun, hba_private);
752     } else {
753         assert(cmd.len != 0);
754         trace_scsi_req_parsed(d->id, lun, tag, buf[0],
755                               cmd.mode, cmd.xfer);
756         if (cmd.lba != -1) {
757             trace_scsi_req_parsed_lba(d->id, lun, tag, buf[0],
758                                       cmd.lba);
759         }
760 
761         if (cmd.xfer > INT32_MAX) {
762             req = scsi_req_alloc(&reqops_invalid_field, d, tag, lun, hba_private);
763         } else if (ops) {
764             req = scsi_req_alloc(ops, d, tag, lun, hba_private);
765         } else {
766             req = scsi_device_alloc_req(d, tag, lun, buf, hba_private);
767         }
768     }
769 
770     req->cmd = cmd;
771     req->residual = req->cmd.xfer;
772 
773     switch (buf[0]) {
774     case INQUIRY:
775         trace_scsi_inquiry(d->id, lun, tag, cmd.buf[1], cmd.buf[2]);
776         break;
777     case TEST_UNIT_READY:
778         trace_scsi_test_unit_ready(d->id, lun, tag);
779         break;
780     case REPORT_LUNS:
781         trace_scsi_report_luns(d->id, lun, tag);
782         break;
783     case REQUEST_SENSE:
784         trace_scsi_request_sense(d->id, lun, tag);
785         break;
786     default:
787         break;
788     }
789 
790     return req;
791 }
792 
793 uint8_t *scsi_req_get_buf(SCSIRequest *req)
794 {
795     return req->ops->get_buf(req);
796 }
797 
798 static void scsi_clear_unit_attention(SCSIRequest *req)
799 {
800     SCSISense *ua;
801     if (req->dev->unit_attention.key != UNIT_ATTENTION &&
802         req->bus->unit_attention.key != UNIT_ATTENTION) {
803         return;
804     }
805 
806     /*
807      * If an INQUIRY command enters the enabled command state,
808      * the device server shall [not] clear any unit attention condition;
809      * See also MMC-6, paragraphs 6.5 and 6.6.2.
810      */
811     if (req->cmd.buf[0] == INQUIRY ||
812         req->cmd.buf[0] == GET_CONFIGURATION ||
813         req->cmd.buf[0] == GET_EVENT_STATUS_NOTIFICATION) {
814         return;
815     }
816 
817     if (req->dev->unit_attention.key == UNIT_ATTENTION) {
818         ua = &req->dev->unit_attention;
819     } else {
820         ua = &req->bus->unit_attention;
821     }
822 
823     /*
824      * If a REPORT LUNS command enters the enabled command state, [...]
825      * the device server shall clear any pending unit attention condition
826      * with an additional sense code of REPORTED LUNS DATA HAS CHANGED.
827      */
828     if (req->cmd.buf[0] == REPORT_LUNS &&
829         !(ua->asc == SENSE_CODE(REPORTED_LUNS_CHANGED).asc &&
830           ua->ascq == SENSE_CODE(REPORTED_LUNS_CHANGED).ascq)) {
831         return;
832     }
833 
834     *ua = SENSE_CODE(NO_SENSE);
835 }
836 
837 int scsi_req_get_sense(SCSIRequest *req, uint8_t *buf, int len)
838 {
839     int ret;
840 
841     assert(len >= 14);
842     if (!req->sense_len) {
843         return 0;
844     }
845 
846     ret = scsi_convert_sense(req->sense, req->sense_len, buf, len, true);
847 
848     /*
849      * FIXME: clearing unit attention conditions upon autosense should be done
850      * only if the UA_INTLCK_CTRL field in the Control mode page is set to 00b
851      * (SAM-5, 5.14).
852      *
853      * We assume UA_INTLCK_CTRL to be 00b for HBAs that support autosense, and
854      * 10b for HBAs that do not support it (do not call scsi_req_get_sense).
855      * Here we handle unit attention clearing for UA_INTLCK_CTRL == 00b.
856      */
857     if (req->dev->sense_is_ua) {
858         scsi_device_unit_attention_reported(req->dev);
859         req->dev->sense_len = 0;
860         req->dev->sense_is_ua = false;
861     }
862     return ret;
863 }
864 
865 int scsi_device_get_sense(SCSIDevice *dev, uint8_t *buf, int len, bool fixed)
866 {
867     return scsi_convert_sense(dev->sense, dev->sense_len, buf, len, fixed);
868 }
869 
870 void scsi_req_build_sense(SCSIRequest *req, SCSISense sense)
871 {
872     trace_scsi_req_build_sense(req->dev->id, req->lun, req->tag,
873                                sense.key, sense.asc, sense.ascq);
874     req->sense_len = scsi_build_sense(req->sense, sense);
875 }
876 
877 static void scsi_req_enqueue_internal(SCSIRequest *req)
878 {
879     assert(!req->enqueued);
880     scsi_req_ref(req);
881     if (req->bus->info->get_sg_list) {
882         req->sg = req->bus->info->get_sg_list(req);
883     } else {
884         req->sg = NULL;
885     }
886     req->enqueued = true;
887     QTAILQ_INSERT_TAIL(&req->dev->requests, req, next);
888 }
889 
890 int32_t scsi_req_enqueue(SCSIRequest *req)
891 {
892     int32_t rc;
893 
894     assert(!req->retry);
895     scsi_req_enqueue_internal(req);
896     scsi_req_ref(req);
897     rc = req->ops->send_command(req, req->cmd.buf);
898     scsi_req_unref(req);
899     return rc;
900 }
901 
902 static void scsi_req_dequeue(SCSIRequest *req)
903 {
904     trace_scsi_req_dequeue(req->dev->id, req->lun, req->tag);
905     req->retry = false;
906     if (req->enqueued) {
907         QTAILQ_REMOVE(&req->dev->requests, req, next);
908         req->enqueued = false;
909         scsi_req_unref(req);
910     }
911 }
912 
913 static int scsi_get_performance_length(int num_desc, int type, int data_type)
914 {
915     /* MMC-6, paragraph 6.7.  */
916     switch (type) {
917     case 0:
918         if ((data_type & 3) == 0) {
919             /* Each descriptor is as in Table 295 - Nominal performance.  */
920             return 16 * num_desc + 8;
921         } else {
922             /* Each descriptor is as in Table 296 - Exceptions.  */
923             return 6 * num_desc + 8;
924         }
925     case 1:
926     case 4:
927     case 5:
928         return 8 * num_desc + 8;
929     case 2:
930         return 2048 * num_desc + 8;
931     case 3:
932         return 16 * num_desc + 8;
933     default:
934         return 8;
935     }
936 }
937 
938 static int ata_passthrough_xfer_unit(SCSIDevice *dev, uint8_t *buf)
939 {
940     int byte_block = (buf[2] >> 2) & 0x1;
941     int type = (buf[2] >> 4) & 0x1;
942     int xfer_unit;
943 
944     if (byte_block) {
945         if (type) {
946             xfer_unit = dev->blocksize;
947         } else {
948             xfer_unit = 512;
949         }
950     } else {
951         xfer_unit = 1;
952     }
953 
954     return xfer_unit;
955 }
956 
957 static int ata_passthrough_12_xfer(SCSIDevice *dev, uint8_t *buf)
958 {
959     int length = buf[2] & 0x3;
960     int xfer;
961     int unit = ata_passthrough_xfer_unit(dev, buf);
962 
963     switch (length) {
964     case 0:
965     case 3: /* USB-specific.  */
966     default:
967         xfer = 0;
968         break;
969     case 1:
970         xfer = buf[3];
971         break;
972     case 2:
973         xfer = buf[4];
974         break;
975     }
976 
977     return xfer * unit;
978 }
979 
980 static int ata_passthrough_16_xfer(SCSIDevice *dev, uint8_t *buf)
981 {
982     int extend = buf[1] & 0x1;
983     int length = buf[2] & 0x3;
984     int xfer;
985     int unit = ata_passthrough_xfer_unit(dev, buf);
986 
987     switch (length) {
988     case 0:
989     case 3: /* USB-specific.  */
990     default:
991         xfer = 0;
992         break;
993     case 1:
994         xfer = buf[4];
995         xfer |= (extend ? buf[3] << 8 : 0);
996         break;
997     case 2:
998         xfer = buf[6];
999         xfer |= (extend ? buf[5] << 8 : 0);
1000         break;
1001     }
1002 
1003     return xfer * unit;
1004 }
1005 
1006 static int scsi_req_xfer(SCSICommand *cmd, SCSIDevice *dev, uint8_t *buf)
1007 {
1008     cmd->xfer = scsi_cdb_xfer(buf);
1009     switch (buf[0]) {
1010     case TEST_UNIT_READY:
1011     case REWIND:
1012     case START_STOP:
1013     case SET_CAPACITY:
1014     case WRITE_FILEMARKS:
1015     case WRITE_FILEMARKS_16:
1016     case SPACE:
1017     case RESERVE:
1018     case RELEASE:
1019     case ERASE:
1020     case ALLOW_MEDIUM_REMOVAL:
1021     case SEEK_10:
1022     case SYNCHRONIZE_CACHE:
1023     case SYNCHRONIZE_CACHE_16:
1024     case LOCATE_16:
1025     case LOCK_UNLOCK_CACHE:
1026     case SET_CD_SPEED:
1027     case SET_LIMITS:
1028     case WRITE_LONG_10:
1029     case UPDATE_BLOCK:
1030     case RESERVE_TRACK:
1031     case SET_READ_AHEAD:
1032     case PRE_FETCH:
1033     case PRE_FETCH_16:
1034     case ALLOW_OVERWRITE:
1035         cmd->xfer = 0;
1036         break;
1037     case VERIFY_10:
1038     case VERIFY_12:
1039     case VERIFY_16:
1040         if ((buf[1] & 2) == 0) {
1041             cmd->xfer = 0;
1042         } else if ((buf[1] & 4) != 0) {
1043             cmd->xfer = 1;
1044         }
1045         cmd->xfer *= dev->blocksize;
1046         break;
1047     case MODE_SENSE:
1048         break;
1049     case WRITE_SAME_10:
1050     case WRITE_SAME_16:
1051         cmd->xfer = buf[1] & 1 ? 0 : dev->blocksize;
1052         break;
1053     case READ_CAPACITY_10:
1054         cmd->xfer = 8;
1055         break;
1056     case READ_BLOCK_LIMITS:
1057         cmd->xfer = 6;
1058         break;
1059     case SEND_VOLUME_TAG:
1060         /* GPCMD_SET_STREAMING from multimedia commands.  */
1061         if (dev->type == TYPE_ROM) {
1062             cmd->xfer = buf[10] | (buf[9] << 8);
1063         } else {
1064             cmd->xfer = buf[9] | (buf[8] << 8);
1065         }
1066         break;
1067     case WRITE_6:
1068         /* length 0 means 256 blocks */
1069         if (cmd->xfer == 0) {
1070             cmd->xfer = 256;
1071         }
1072         /* fall through */
1073     case WRITE_10:
1074     case WRITE_VERIFY_10:
1075     case WRITE_12:
1076     case WRITE_VERIFY_12:
1077     case WRITE_16:
1078     case WRITE_VERIFY_16:
1079         cmd->xfer *= dev->blocksize;
1080         break;
1081     case READ_6:
1082     case READ_REVERSE:
1083         /* length 0 means 256 blocks */
1084         if (cmd->xfer == 0) {
1085             cmd->xfer = 256;
1086         }
1087         /* fall through */
1088     case READ_10:
1089     case READ_12:
1090     case READ_16:
1091         cmd->xfer *= dev->blocksize;
1092         break;
1093     case FORMAT_UNIT:
1094         /* MMC mandates the parameter list to be 12-bytes long.  Parameters
1095          * for block devices are restricted to the header right now.  */
1096         if (dev->type == TYPE_ROM && (buf[1] & 16)) {
1097             cmd->xfer = 12;
1098         } else {
1099             cmd->xfer = (buf[1] & 16) == 0 ? 0 : (buf[1] & 32 ? 8 : 4);
1100         }
1101         break;
1102     case INQUIRY:
1103     case RECEIVE_DIAGNOSTIC:
1104     case SEND_DIAGNOSTIC:
1105         cmd->xfer = buf[4] | (buf[3] << 8);
1106         break;
1107     case READ_CD:
1108     case READ_BUFFER:
1109     case WRITE_BUFFER:
1110     case SEND_CUE_SHEET:
1111         cmd->xfer = buf[8] | (buf[7] << 8) | (buf[6] << 16);
1112         break;
1113     case PERSISTENT_RESERVE_OUT:
1114         cmd->xfer = ldl_be_p(&buf[5]) & 0xffffffffULL;
1115         break;
1116     case ERASE_12:
1117         if (dev->type == TYPE_ROM) {
1118             /* MMC command GET PERFORMANCE.  */
1119             cmd->xfer = scsi_get_performance_length(buf[9] | (buf[8] << 8),
1120                                                     buf[10], buf[1] & 0x1f);
1121         }
1122         break;
1123     case MECHANISM_STATUS:
1124     case READ_DVD_STRUCTURE:
1125     case SEND_DVD_STRUCTURE:
1126     case MAINTENANCE_OUT:
1127     case MAINTENANCE_IN:
1128         if (dev->type == TYPE_ROM) {
1129             /* GPCMD_REPORT_KEY and GPCMD_SEND_KEY from multi media commands */
1130             cmd->xfer = buf[9] | (buf[8] << 8);
1131         }
1132         break;
1133     case ATA_PASSTHROUGH_12:
1134         if (dev->type == TYPE_ROM) {
1135             /* BLANK command of MMC */
1136             cmd->xfer = 0;
1137         } else {
1138             cmd->xfer = ata_passthrough_12_xfer(dev, buf);
1139         }
1140         break;
1141     case ATA_PASSTHROUGH_16:
1142         cmd->xfer = ata_passthrough_16_xfer(dev, buf);
1143         break;
1144     }
1145     return 0;
1146 }
1147 
1148 static int scsi_req_stream_xfer(SCSICommand *cmd, SCSIDevice *dev, uint8_t *buf)
1149 {
1150     switch (buf[0]) {
1151     /* stream commands */
1152     case ERASE_12:
1153     case ERASE_16:
1154         cmd->xfer = 0;
1155         break;
1156     case READ_6:
1157     case READ_REVERSE:
1158     case RECOVER_BUFFERED_DATA:
1159     case WRITE_6:
1160         cmd->xfer = buf[4] | (buf[3] << 8) | (buf[2] << 16);
1161         if (buf[1] & 0x01) { /* fixed */
1162             cmd->xfer *= dev->blocksize;
1163         }
1164         break;
1165     case READ_16:
1166     case READ_REVERSE_16:
1167     case VERIFY_16:
1168     case WRITE_16:
1169         cmd->xfer = buf[14] | (buf[13] << 8) | (buf[12] << 16);
1170         if (buf[1] & 0x01) { /* fixed */
1171             cmd->xfer *= dev->blocksize;
1172         }
1173         break;
1174     case REWIND:
1175     case LOAD_UNLOAD:
1176         cmd->xfer = 0;
1177         break;
1178     case SPACE_16:
1179         cmd->xfer = buf[13] | (buf[12] << 8);
1180         break;
1181     case READ_POSITION:
1182         switch (buf[1] & 0x1f) /* operation code */ {
1183         case SHORT_FORM_BLOCK_ID:
1184         case SHORT_FORM_VENDOR_SPECIFIC:
1185             cmd->xfer = 20;
1186             break;
1187         case LONG_FORM:
1188             cmd->xfer = 32;
1189             break;
1190         case EXTENDED_FORM:
1191             cmd->xfer = buf[8] | (buf[7] << 8);
1192             break;
1193         default:
1194             return -1;
1195         }
1196 
1197         break;
1198     case FORMAT_UNIT:
1199         cmd->xfer = buf[4] | (buf[3] << 8);
1200         break;
1201     /* generic commands */
1202     default:
1203         return scsi_req_xfer(cmd, dev, buf);
1204     }
1205     return 0;
1206 }
1207 
1208 static int scsi_req_medium_changer_xfer(SCSICommand *cmd, SCSIDevice *dev, uint8_t *buf)
1209 {
1210     switch (buf[0]) {
1211     /* medium changer commands */
1212     case EXCHANGE_MEDIUM:
1213     case INITIALIZE_ELEMENT_STATUS:
1214     case INITIALIZE_ELEMENT_STATUS_WITH_RANGE:
1215     case MOVE_MEDIUM:
1216     case POSITION_TO_ELEMENT:
1217         cmd->xfer = 0;
1218         break;
1219     case READ_ELEMENT_STATUS:
1220         cmd->xfer = buf[9] | (buf[8] << 8) | (buf[7] << 16);
1221         break;
1222 
1223     /* generic commands */
1224     default:
1225         return scsi_req_xfer(cmd, dev, buf);
1226     }
1227     return 0;
1228 }
1229 
1230 static int scsi_req_scanner_length(SCSICommand *cmd, SCSIDevice *dev, uint8_t *buf)
1231 {
1232     switch (buf[0]) {
1233     /* Scanner commands */
1234     case OBJECT_POSITION:
1235         cmd->xfer = 0;
1236         break;
1237     case SCAN:
1238         cmd->xfer = buf[4];
1239         break;
1240     case READ_10:
1241     case SEND:
1242     case GET_WINDOW:
1243     case SET_WINDOW:
1244         cmd->xfer = buf[8] | (buf[7] << 8) | (buf[6] << 16);
1245         break;
1246     default:
1247         /* GET_DATA_BUFFER_STATUS xfer handled by scsi_req_xfer */
1248         return scsi_req_xfer(cmd, dev, buf);
1249     }
1250 
1251     return 0;
1252 }
1253 
1254 static void scsi_cmd_xfer_mode(SCSICommand *cmd)
1255 {
1256     if (!cmd->xfer) {
1257         cmd->mode = SCSI_XFER_NONE;
1258         return;
1259     }
1260     switch (cmd->buf[0]) {
1261     case WRITE_6:
1262     case WRITE_10:
1263     case WRITE_VERIFY_10:
1264     case WRITE_12:
1265     case WRITE_VERIFY_12:
1266     case WRITE_16:
1267     case WRITE_VERIFY_16:
1268     case VERIFY_10:
1269     case VERIFY_12:
1270     case VERIFY_16:
1271     case COPY:
1272     case COPY_VERIFY:
1273     case COMPARE:
1274     case CHANGE_DEFINITION:
1275     case LOG_SELECT:
1276     case MODE_SELECT:
1277     case MODE_SELECT_10:
1278     case SEND_DIAGNOSTIC:
1279     case WRITE_BUFFER:
1280     case FORMAT_UNIT:
1281     case REASSIGN_BLOCKS:
1282     case SEARCH_EQUAL:
1283     case SEARCH_HIGH:
1284     case SEARCH_LOW:
1285     case UPDATE_BLOCK:
1286     case WRITE_LONG_10:
1287     case WRITE_SAME_10:
1288     case WRITE_SAME_16:
1289     case UNMAP:
1290     case SEARCH_HIGH_12:
1291     case SEARCH_EQUAL_12:
1292     case SEARCH_LOW_12:
1293     case MEDIUM_SCAN:
1294     case SEND_VOLUME_TAG:
1295     case SEND_CUE_SHEET:
1296     case SEND_DVD_STRUCTURE:
1297     case PERSISTENT_RESERVE_OUT:
1298     case MAINTENANCE_OUT:
1299     case SET_WINDOW:
1300     case SCAN:
1301         /* SCAN conflicts with START_STOP.  START_STOP has cmd->xfer set to 0 for
1302          * non-scanner devices, so we only get here for SCAN and not for START_STOP.
1303          */
1304         cmd->mode = SCSI_XFER_TO_DEV;
1305         break;
1306     case ATA_PASSTHROUGH_12:
1307     case ATA_PASSTHROUGH_16:
1308         /* T_DIR */
1309         cmd->mode = (cmd->buf[2] & 0x8) ?
1310                    SCSI_XFER_FROM_DEV : SCSI_XFER_TO_DEV;
1311         break;
1312     default:
1313         cmd->mode = SCSI_XFER_FROM_DEV;
1314         break;
1315     }
1316 }
1317 
1318 int scsi_req_parse_cdb(SCSIDevice *dev, SCSICommand *cmd, uint8_t *buf,
1319                        size_t buf_len)
1320 {
1321     int rc;
1322     int len;
1323 
1324     cmd->lba = -1;
1325     len = scsi_cdb_length(buf);
1326     if (len < 0 || len > buf_len) {
1327         return -1;
1328     }
1329 
1330     cmd->len = len;
1331     switch (dev->type) {
1332     case TYPE_TAPE:
1333         rc = scsi_req_stream_xfer(cmd, dev, buf);
1334         break;
1335     case TYPE_MEDIUM_CHANGER:
1336         rc = scsi_req_medium_changer_xfer(cmd, dev, buf);
1337         break;
1338     case TYPE_SCANNER:
1339         rc = scsi_req_scanner_length(cmd, dev, buf);
1340         break;
1341     default:
1342         rc = scsi_req_xfer(cmd, dev, buf);
1343         break;
1344     }
1345 
1346     if (rc != 0)
1347         return rc;
1348 
1349     memcpy(cmd->buf, buf, cmd->len);
1350     scsi_cmd_xfer_mode(cmd);
1351     cmd->lba = scsi_cmd_lba(cmd);
1352     return 0;
1353 }
1354 
1355 void scsi_device_report_change(SCSIDevice *dev, SCSISense sense)
1356 {
1357     SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, dev->qdev.parent_bus);
1358 
1359     scsi_device_set_ua(dev, sense);
1360     if (bus->info->change) {
1361         bus->info->change(bus, dev, sense);
1362     }
1363 }
1364 
1365 SCSIRequest *scsi_req_ref(SCSIRequest *req)
1366 {
1367     assert(req->refcount > 0);
1368     req->refcount++;
1369     return req;
1370 }
1371 
1372 void scsi_req_unref(SCSIRequest *req)
1373 {
1374     assert(req->refcount > 0);
1375     if (--req->refcount == 0) {
1376         BusState *qbus = req->dev->qdev.parent_bus;
1377         SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, qbus);
1378 
1379         if (bus->info->free_request && req->hba_private) {
1380             bus->info->free_request(bus, req->hba_private);
1381         }
1382         if (req->ops->free_req) {
1383             req->ops->free_req(req);
1384         }
1385         object_unref(OBJECT(req->dev));
1386         object_unref(OBJECT(qbus->parent));
1387         g_free(req);
1388     }
1389 }
1390 
1391 /* Tell the device that we finished processing this chunk of I/O.  It
1392    will start the next chunk or complete the command.  */
1393 void scsi_req_continue(SCSIRequest *req)
1394 {
1395     if (req->io_canceled) {
1396         trace_scsi_req_continue_canceled(req->dev->id, req->lun, req->tag);
1397         return;
1398     }
1399     trace_scsi_req_continue(req->dev->id, req->lun, req->tag);
1400     if (req->cmd.mode == SCSI_XFER_TO_DEV) {
1401         req->ops->write_data(req);
1402     } else {
1403         req->ops->read_data(req);
1404     }
1405 }
1406 
1407 /* Called by the devices when data is ready for the HBA.  The HBA should
1408    start a DMA operation to read or fill the device's data buffer.
1409    Once it completes, calling scsi_req_continue will restart I/O.  */
1410 void scsi_req_data(SCSIRequest *req, int len)
1411 {
1412     uint8_t *buf;
1413     if (req->io_canceled) {
1414         trace_scsi_req_data_canceled(req->dev->id, req->lun, req->tag, len);
1415         return;
1416     }
1417     trace_scsi_req_data(req->dev->id, req->lun, req->tag, len);
1418     assert(req->cmd.mode != SCSI_XFER_NONE);
1419     if (!req->sg) {
1420         req->residual -= len;
1421         req->bus->info->transfer_data(req, len);
1422         return;
1423     }
1424 
1425     /* If the device calls scsi_req_data and the HBA specified a
1426      * scatter/gather list, the transfer has to happen in a single
1427      * step.  */
1428     assert(!req->dma_started);
1429     req->dma_started = true;
1430 
1431     buf = scsi_req_get_buf(req);
1432     if (req->cmd.mode == SCSI_XFER_FROM_DEV) {
1433         dma_buf_read(buf, len, &req->residual, req->sg,
1434                      MEMTXATTRS_UNSPECIFIED);
1435     } else {
1436         dma_buf_write(buf, len, &req->residual, req->sg,
1437                       MEMTXATTRS_UNSPECIFIED);
1438     }
1439     scsi_req_continue(req);
1440 }
1441 
1442 void scsi_req_print(SCSIRequest *req)
1443 {
1444     FILE *fp = stderr;
1445     int i;
1446 
1447     fprintf(fp, "[%s id=%d] %s",
1448             req->dev->qdev.parent_bus->name,
1449             req->dev->id,
1450             scsi_command_name(req->cmd.buf[0]));
1451     for (i = 1; i < req->cmd.len; i++) {
1452         fprintf(fp, " 0x%02x", req->cmd.buf[i]);
1453     }
1454     switch (req->cmd.mode) {
1455     case SCSI_XFER_NONE:
1456         fprintf(fp, " - none\n");
1457         break;
1458     case SCSI_XFER_FROM_DEV:
1459         fprintf(fp, " - from-dev len=%zd\n", req->cmd.xfer);
1460         break;
1461     case SCSI_XFER_TO_DEV:
1462         fprintf(fp, " - to-dev len=%zd\n", req->cmd.xfer);
1463         break;
1464     default:
1465         fprintf(fp, " - Oops\n");
1466         break;
1467     }
1468 }
1469 
1470 void scsi_req_complete_failed(SCSIRequest *req, int host_status)
1471 {
1472     SCSISense sense;
1473     int status;
1474 
1475     assert(req->status == -1 && req->host_status == -1);
1476     assert(req->ops != &reqops_unit_attention);
1477 
1478     if (!req->bus->info->fail) {
1479         status = scsi_sense_from_host_status(req->host_status, &sense);
1480         if (status == CHECK_CONDITION) {
1481             scsi_req_build_sense(req, sense);
1482         }
1483         scsi_req_complete(req, status);
1484         return;
1485     }
1486 
1487     req->host_status = host_status;
1488     scsi_req_ref(req);
1489     scsi_req_dequeue(req);
1490     req->bus->info->fail(req);
1491 
1492     /* Cancelled requests might end up being completed instead of cancelled */
1493     notifier_list_notify(&req->cancel_notifiers, req);
1494     scsi_req_unref(req);
1495 }
1496 
1497 void scsi_req_complete(SCSIRequest *req, int status)
1498 {
1499     assert(req->status == -1 && req->host_status == -1);
1500     req->status = status;
1501     req->host_status = SCSI_HOST_OK;
1502 
1503     assert(req->sense_len <= sizeof(req->sense));
1504     if (status == GOOD) {
1505         req->sense_len = 0;
1506     }
1507 
1508     if (req->sense_len) {
1509         memcpy(req->dev->sense, req->sense, req->sense_len);
1510         req->dev->sense_len = req->sense_len;
1511         req->dev->sense_is_ua = (req->ops == &reqops_unit_attention);
1512     } else {
1513         req->dev->sense_len = 0;
1514         req->dev->sense_is_ua = false;
1515     }
1516 
1517     /*
1518      * Unit attention state is now stored in the device's sense buffer
1519      * if the HBA didn't do autosense.  Clear the pending unit attention
1520      * flags.
1521      */
1522     scsi_clear_unit_attention(req);
1523 
1524     scsi_req_ref(req);
1525     scsi_req_dequeue(req);
1526     req->bus->info->complete(req, req->residual);
1527 
1528     /* Cancelled requests might end up being completed instead of cancelled */
1529     notifier_list_notify(&req->cancel_notifiers, req);
1530     scsi_req_unref(req);
1531 }
1532 
1533 /* Called by the devices when the request is canceled. */
1534 void scsi_req_cancel_complete(SCSIRequest *req)
1535 {
1536     assert(req->io_canceled);
1537     if (req->bus->info->cancel) {
1538         req->bus->info->cancel(req);
1539     }
1540     notifier_list_notify(&req->cancel_notifiers, req);
1541     scsi_req_unref(req);
1542 }
1543 
1544 /* Cancel @req asynchronously. @notifier is added to @req's cancellation
1545  * notifier list, the bus will be notified the requests cancellation is
1546  * completed.
1547  * */
1548 void scsi_req_cancel_async(SCSIRequest *req, Notifier *notifier)
1549 {
1550     trace_scsi_req_cancel(req->dev->id, req->lun, req->tag);
1551     if (notifier) {
1552         notifier_list_add(&req->cancel_notifiers, notifier);
1553     }
1554     if (req->io_canceled) {
1555         /* A blk_aio_cancel_async is pending; when it finishes,
1556          * scsi_req_cancel_complete will be called and will
1557          * call the notifier we just added.  Just wait for that.
1558          */
1559         assert(req->aiocb);
1560         return;
1561     }
1562     /* Dropped in scsi_req_cancel_complete.  */
1563     scsi_req_ref(req);
1564     scsi_req_dequeue(req);
1565     req->io_canceled = true;
1566     if (req->aiocb) {
1567         blk_aio_cancel_async(req->aiocb);
1568     } else {
1569         scsi_req_cancel_complete(req);
1570     }
1571 }
1572 
1573 void scsi_req_cancel(SCSIRequest *req)
1574 {
1575     trace_scsi_req_cancel(req->dev->id, req->lun, req->tag);
1576     if (!req->enqueued) {
1577         return;
1578     }
1579     assert(!req->io_canceled);
1580     /* Dropped in scsi_req_cancel_complete.  */
1581     scsi_req_ref(req);
1582     scsi_req_dequeue(req);
1583     req->io_canceled = true;
1584     if (req->aiocb) {
1585         blk_aio_cancel(req->aiocb);
1586     } else {
1587         scsi_req_cancel_complete(req);
1588     }
1589 }
1590 
1591 static int scsi_ua_precedence(SCSISense sense)
1592 {
1593     if (sense.key != UNIT_ATTENTION) {
1594         return INT_MAX;
1595     }
1596     if (sense.asc == 0x29 && sense.ascq == 0x04) {
1597         /* DEVICE INTERNAL RESET goes with POWER ON OCCURRED */
1598         return 1;
1599     } else if (sense.asc == 0x3F && sense.ascq == 0x01) {
1600         /* MICROCODE HAS BEEN CHANGED goes with SCSI BUS RESET OCCURRED */
1601         return 2;
1602     } else if (sense.asc == 0x29 && (sense.ascq == 0x05 || sense.ascq == 0x06)) {
1603         /* These two go with "all others". */
1604         ;
1605     } else if (sense.asc == 0x29 && sense.ascq <= 0x07) {
1606         /* POWER ON, RESET OR BUS DEVICE RESET OCCURRED = 0
1607          * POWER ON OCCURRED = 1
1608          * SCSI BUS RESET OCCURRED = 2
1609          * BUS DEVICE RESET FUNCTION OCCURRED = 3
1610          * I_T NEXUS LOSS OCCURRED = 7
1611          */
1612         return sense.ascq;
1613     } else if (sense.asc == 0x2F && sense.ascq == 0x01) {
1614         /* COMMANDS CLEARED BY POWER LOSS NOTIFICATION  */
1615         return 8;
1616     }
1617     return (sense.asc << 8) | sense.ascq;
1618 }
1619 
1620 void scsi_bus_set_ua(SCSIBus *bus, SCSISense sense)
1621 {
1622     int prec1, prec2;
1623     if (sense.key != UNIT_ATTENTION) {
1624         return;
1625     }
1626 
1627     /*
1628      * Override a pre-existing unit attention condition, except for a more
1629      * important reset condition.
1630      */
1631     prec1 = scsi_ua_precedence(bus->unit_attention);
1632     prec2 = scsi_ua_precedence(sense);
1633     if (prec2 < prec1) {
1634         bus->unit_attention = sense;
1635     }
1636 }
1637 
1638 void scsi_device_set_ua(SCSIDevice *sdev, SCSISense sense)
1639 {
1640     int prec1, prec2;
1641     if (sense.key != UNIT_ATTENTION) {
1642         return;
1643     }
1644     trace_scsi_device_set_ua(sdev->id, sdev->lun, sense.key,
1645                              sense.asc, sense.ascq);
1646 
1647     /*
1648      * Override a pre-existing unit attention condition, except for a more
1649      * important reset condition.
1650     */
1651     prec1 = scsi_ua_precedence(sdev->unit_attention);
1652     prec2 = scsi_ua_precedence(sense);
1653     if (prec2 < prec1) {
1654         sdev->unit_attention = sense;
1655     }
1656 }
1657 
1658 void scsi_device_purge_requests(SCSIDevice *sdev, SCSISense sense)
1659 {
1660     SCSIRequest *req;
1661 
1662     aio_context_acquire(blk_get_aio_context(sdev->conf.blk));
1663     while (!QTAILQ_EMPTY(&sdev->requests)) {
1664         req = QTAILQ_FIRST(&sdev->requests);
1665         scsi_req_cancel_async(req, NULL);
1666     }
1667     blk_drain(sdev->conf.blk);
1668     aio_context_release(blk_get_aio_context(sdev->conf.blk));
1669     scsi_device_set_ua(sdev, sense);
1670 }
1671 
1672 static char *scsibus_get_dev_path(DeviceState *dev)
1673 {
1674     SCSIDevice *d = SCSI_DEVICE(dev);
1675     DeviceState *hba = dev->parent_bus->parent;
1676     char *id;
1677     char *path;
1678 
1679     id = qdev_get_dev_path(hba);
1680     if (id) {
1681         path = g_strdup_printf("%s/%d:%d:%d", id, d->channel, d->id, d->lun);
1682     } else {
1683         path = g_strdup_printf("%d:%d:%d", d->channel, d->id, d->lun);
1684     }
1685     g_free(id);
1686     return path;
1687 }
1688 
1689 static char *scsibus_get_fw_dev_path(DeviceState *dev)
1690 {
1691     SCSIDevice *d = SCSI_DEVICE(dev);
1692     return g_strdup_printf("channel@%x/%s@%x,%x", d->channel,
1693                            qdev_fw_name(dev), d->id, d->lun);
1694 }
1695 
1696 /* SCSI request list.  For simplicity, pv points to the whole device */
1697 
1698 static int put_scsi_requests(QEMUFile *f, void *pv, size_t size,
1699                              const VMStateField *field, JSONWriter *vmdesc)
1700 {
1701     SCSIDevice *s = pv;
1702     SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, s->qdev.parent_bus);
1703     SCSIRequest *req;
1704 
1705     QTAILQ_FOREACH(req, &s->requests, next) {
1706         assert(!req->io_canceled);
1707         assert(req->status == -1 && req->host_status == -1);
1708         assert(req->enqueued);
1709 
1710         qemu_put_sbyte(f, req->retry ? 1 : 2);
1711         qemu_put_buffer(f, req->cmd.buf, sizeof(req->cmd.buf));
1712         qemu_put_be32s(f, &req->tag);
1713         qemu_put_be32s(f, &req->lun);
1714         if (bus->info->save_request) {
1715             bus->info->save_request(f, req);
1716         }
1717         if (req->ops->save_request) {
1718             req->ops->save_request(f, req);
1719         }
1720     }
1721     qemu_put_sbyte(f, 0);
1722 
1723     return 0;
1724 }
1725 
1726 static int get_scsi_requests(QEMUFile *f, void *pv, size_t size,
1727                              const VMStateField *field)
1728 {
1729     SCSIDevice *s = pv;
1730     SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, s->qdev.parent_bus);
1731     int8_t sbyte;
1732 
1733     while ((sbyte = qemu_get_sbyte(f)) > 0) {
1734         uint8_t buf[SCSI_CMD_BUF_SIZE];
1735         uint32_t tag;
1736         uint32_t lun;
1737         SCSIRequest *req;
1738 
1739         qemu_get_buffer(f, buf, sizeof(buf));
1740         qemu_get_be32s(f, &tag);
1741         qemu_get_be32s(f, &lun);
1742         /*
1743          * A too-short CDB would have been rejected by scsi_req_new, so just use
1744          * SCSI_CMD_BUF_SIZE as the CDB length.
1745          */
1746         req = scsi_req_new(s, tag, lun, buf, sizeof(buf), NULL);
1747         req->retry = (sbyte == 1);
1748         if (bus->info->load_request) {
1749             req->hba_private = bus->info->load_request(f, req);
1750         }
1751         if (req->ops->load_request) {
1752             req->ops->load_request(f, req);
1753         }
1754 
1755         /* Just restart it later.  */
1756         scsi_req_enqueue_internal(req);
1757 
1758         /* At this point, the request will be kept alive by the reference
1759          * added by scsi_req_enqueue_internal, so we can release our reference.
1760          * The HBA of course will add its own reference in the load_request
1761          * callback if it needs to hold on the SCSIRequest.
1762          */
1763         scsi_req_unref(req);
1764     }
1765 
1766     return 0;
1767 }
1768 
1769 static const VMStateInfo vmstate_info_scsi_requests = {
1770     .name = "scsi-requests",
1771     .get  = get_scsi_requests,
1772     .put  = put_scsi_requests,
1773 };
1774 
1775 static bool scsi_sense_state_needed(void *opaque)
1776 {
1777     SCSIDevice *s = opaque;
1778 
1779     return s->sense_len > SCSI_SENSE_BUF_SIZE_OLD;
1780 }
1781 
1782 static const VMStateDescription vmstate_scsi_sense_state = {
1783     .name = "SCSIDevice/sense",
1784     .version_id = 1,
1785     .minimum_version_id = 1,
1786     .needed = scsi_sense_state_needed,
1787     .fields = (VMStateField[]) {
1788         VMSTATE_UINT8_SUB_ARRAY(sense, SCSIDevice,
1789                                 SCSI_SENSE_BUF_SIZE_OLD,
1790                                 SCSI_SENSE_BUF_SIZE - SCSI_SENSE_BUF_SIZE_OLD),
1791         VMSTATE_END_OF_LIST()
1792     }
1793 };
1794 
1795 const VMStateDescription vmstate_scsi_device = {
1796     .name = "SCSIDevice",
1797     .version_id = 1,
1798     .minimum_version_id = 1,
1799     .fields = (VMStateField[]) {
1800         VMSTATE_UINT8(unit_attention.key, SCSIDevice),
1801         VMSTATE_UINT8(unit_attention.asc, SCSIDevice),
1802         VMSTATE_UINT8(unit_attention.ascq, SCSIDevice),
1803         VMSTATE_BOOL(sense_is_ua, SCSIDevice),
1804         VMSTATE_UINT8_SUB_ARRAY(sense, SCSIDevice, 0, SCSI_SENSE_BUF_SIZE_OLD),
1805         VMSTATE_UINT32(sense_len, SCSIDevice),
1806         {
1807             .name         = "requests",
1808             .version_id   = 0,
1809             .field_exists = NULL,
1810             .size         = 0,   /* ouch */
1811             .info         = &vmstate_info_scsi_requests,
1812             .flags        = VMS_SINGLE,
1813             .offset       = 0,
1814         },
1815         VMSTATE_END_OF_LIST()
1816     },
1817     .subsections = (const VMStateDescription*[]) {
1818         &vmstate_scsi_sense_state,
1819         NULL
1820     }
1821 };
1822 
1823 static Property scsi_props[] = {
1824     DEFINE_PROP_UINT32("channel", SCSIDevice, channel, 0),
1825     DEFINE_PROP_UINT32("scsi-id", SCSIDevice, id, -1),
1826     DEFINE_PROP_UINT32("lun", SCSIDevice, lun, -1),
1827     DEFINE_PROP_END_OF_LIST(),
1828 };
1829 
1830 static void scsi_device_class_init(ObjectClass *klass, void *data)
1831 {
1832     DeviceClass *k = DEVICE_CLASS(klass);
1833     set_bit(DEVICE_CATEGORY_STORAGE, k->categories);
1834     k->bus_type  = TYPE_SCSI_BUS;
1835     k->realize   = scsi_qdev_realize;
1836     k->unrealize = scsi_qdev_unrealize;
1837     device_class_set_props(k, scsi_props);
1838 }
1839 
1840 static void scsi_dev_instance_init(Object *obj)
1841 {
1842     DeviceState *dev = DEVICE(obj);
1843     SCSIDevice *s = SCSI_DEVICE(dev);
1844 
1845     device_add_bootindex_property(obj, &s->conf.bootindex,
1846                                   "bootindex", NULL,
1847                                   &s->qdev);
1848 }
1849 
1850 static const TypeInfo scsi_device_type_info = {
1851     .name = TYPE_SCSI_DEVICE,
1852     .parent = TYPE_DEVICE,
1853     .instance_size = sizeof(SCSIDevice),
1854     .abstract = true,
1855     .class_size = sizeof(SCSIDeviceClass),
1856     .class_init = scsi_device_class_init,
1857     .instance_init = scsi_dev_instance_init,
1858 };
1859 
1860 static void scsi_bus_class_init(ObjectClass *klass, void *data)
1861 {
1862     BusClass *k = BUS_CLASS(klass);
1863     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
1864 
1865     k->get_dev_path = scsibus_get_dev_path;
1866     k->get_fw_dev_path = scsibus_get_fw_dev_path;
1867     k->check_address = scsi_bus_check_address;
1868     hc->unplug = qdev_simple_device_unplug_cb;
1869 }
1870 
1871 static const TypeInfo scsi_bus_info = {
1872     .name = TYPE_SCSI_BUS,
1873     .parent = TYPE_BUS,
1874     .instance_size = sizeof(SCSIBus),
1875     .class_init = scsi_bus_class_init,
1876     .interfaces = (InterfaceInfo[]) {
1877         { TYPE_HOTPLUG_HANDLER },
1878         { }
1879     }
1880 };
1881 
1882 static void scsi_register_types(void)
1883 {
1884     type_register_static(&scsi_bus_info);
1885     type_register_static(&scsi_device_type_info);
1886 }
1887 
1888 type_init(scsi_register_types)
1889