hw/scsi/virtio-scsi.c

   1 /*
   2  * Virtio SCSI HBA
   3  *
   4  * Copyright IBM, Corp. 2010
   5  * Copyright Red Hat, Inc. 2011
   6  *
   7  * Authors:
   8  *   Stefan Hajnoczi    <stefanha@linux.vnet.ibm.com>
   9  *   Paolo Bonzini      <pbonzini@redhat.com>
  10  *
  11  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  12  * See the COPYING file in the top-level directory.
  13  *
  14  */
  15
  16 #include "qemu/osdep.h"
  17 #include "qapi/error.h"
  18 #include "standard-headers/linux/virtio_ids.h"
  19 #include "hw/virtio/virtio-scsi.h"
  20 #include "migration/qemu-file-types.h"
  21 #include "qemu/defer-call.h"
  22 #include "qemu/error-report.h"
  23 #include "qemu/iov.h"
  24 #include "qemu/module.h"
  25 #include "sysemu/block-backend.h"
  26 #include "sysemu/dma.h"
  27 #include "hw/qdev-properties.h"
  28 #include "hw/scsi/scsi.h"
  29 #include "scsi/constants.h"
  30 #include "hw/virtio/virtio-bus.h"
  31 #include "hw/virtio/virtio-access.h"
  32 #include "trace.h"
  33
  34 typedef struct VirtIOSCSIReq {
  35     /*
  36      * Note:
  37      * - fields up to resp_iov are initialized by virtio_scsi_init_req;
  38      * - fields starting at vring are zeroed by virtio_scsi_init_req.
  39      */
  40     VirtQueueElement elem;
  41
  42     VirtIOSCSI *dev;
  43     VirtQueue *vq;
  44     QEMUSGList qsgl;
  45     QEMUIOVector resp_iov;
  46
  47     /* Used for two-stage request submission and TMFs deferred to BH */
  48     QTAILQ_ENTRY(VirtIOSCSIReq) next;
  49
  50     /* Used for cancellation of request during TMFs */
  51     int remaining;
  52
  53     SCSIRequest *sreq;
  54     size_t resp_size;
  55     enum SCSIXferMode mode;
  56     union {
  57         VirtIOSCSICmdResp     cmd;
  58         VirtIOSCSICtrlTMFResp tmf;
  59         VirtIOSCSICtrlANResp  an;
  60         VirtIOSCSIEvent       event;
  61     } resp;
  62     union {
  63         VirtIOSCSICmdReq      cmd;
  64         VirtIOSCSICtrlTMFReq  tmf;
  65         VirtIOSCSICtrlANReq   an;
  66     } req;
  67 } VirtIOSCSIReq;
  68
  69 static inline int virtio_scsi_get_lun(uint8_t *lun)
  70 {
  71     return ((lun[2] << 8) | lun[3]) & 0x3FFF;
  72 }
  73
  74 static inline SCSIDevice *virtio_scsi_device_get(VirtIOSCSI *s, uint8_t *lun)
  75 {
  76     if (lun[0] != 1) {
  77         return NULL;
  78     }
  79     if (lun[2] != 0 && !(lun[2] >= 0x40 && lun[2] < 0x80)) {
  80         return NULL;
  81     }
  82     return scsi_device_get(&s->bus, 0, lun[1], virtio_scsi_get_lun(lun));
  83 }
  84
  85 static void virtio_scsi_init_req(VirtIOSCSI *s, VirtQueue *vq, VirtIOSCSIReq *req)
  86 {
  87     VirtIODevice *vdev = VIRTIO_DEVICE(s);
  88     const size_t zero_skip =
  89         offsetof(VirtIOSCSIReq, resp_iov) + sizeof(req->resp_iov);
  90
  91     req->vq = vq;
  92     req->dev = s;
  93     qemu_sglist_init(&req->qsgl, DEVICE(s), 8, vdev->dma_as);
  94     qemu_iovec_init(&req->resp_iov, 1);
  95     memset((uint8_t *)req + zero_skip, 0, sizeof(*req) - zero_skip);
  96 }
  97
  98 static void virtio_scsi_free_req(VirtIOSCSIReq *req)
  99 {
 100     qemu_iovec_destroy(&req->resp_iov);
 101     qemu_sglist_destroy(&req->qsgl);
 102     g_free(req);
 103 }
 104
 105 static void virtio_scsi_complete_req(VirtIOSCSIReq *req)
 106 {
 107     VirtIOSCSI *s = req->dev;
 108     VirtQueue *vq = req->vq;
 109     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 110
 111     qemu_iovec_from_buf(&req->resp_iov, 0, &req->resp, req->resp_size);
 112     virtqueue_push(vq, &req->elem, req->qsgl.size + req->resp_iov.size);
 113     if (s->dataplane_started && !s->dataplane_fenced) {
 114         virtio_notify_irqfd(vdev, vq);
 115     } else {
 116         virtio_notify(vdev, vq);
 117     }
 118
 119     if (req->sreq) {
 120         req->sreq->hba_private = NULL;
 121         scsi_req_unref(req->sreq);
 122     }
 123     virtio_scsi_free_req(req);
 124 }
 125
 126 static void virtio_scsi_complete_req_bh(void *opaque)
 127 {
 128     VirtIOSCSIReq *req = opaque;
 129
 130     virtio_scsi_complete_req(req);
 131 }
 132
 133 /*
 134  * Called from virtio_scsi_do_one_tmf_bh() in main loop thread. The main loop
 135  * thread cannot touch the virtqueue since that could race with an IOThread.
 136  */
 137 static void virtio_scsi_complete_req_from_main_loop(VirtIOSCSIReq *req)
 138 {
 139     VirtIOSCSI *s = req->dev;
 140
 141     if (!s->ctx || s->ctx == qemu_get_aio_context()) {
 142         /* No need to schedule a BH when there is no IOThread */
 143         virtio_scsi_complete_req(req);
 144     } else {
 145         /* Run request completion in the IOThread */
 146         aio_wait_bh_oneshot(s->ctx, virtio_scsi_complete_req_bh, req);
 147     }
 148 }
 149
 150 static void virtio_scsi_bad_req(VirtIOSCSIReq *req)
 151 {
 152     virtio_error(VIRTIO_DEVICE(req->dev), "wrong size for virtio-scsi headers");
 153     virtqueue_detach_element(req->vq, &req->elem, 0);
 154     virtio_scsi_free_req(req);
 155 }
 156
 157 static size_t qemu_sgl_concat(VirtIOSCSIReq *req, struct iovec *iov,
 158                               hwaddr *addr, int num, size_t skip)
 159 {
 160     QEMUSGList *qsgl = &req->qsgl;
 161     size_t copied = 0;
 162
 163     while (num) {
 164         if (skip >= iov->iov_len) {
 165             skip -= iov->iov_len;
 166         } else {
 167             qemu_sglist_add(qsgl, *addr + skip, iov->iov_len - skip);
 168             copied += iov->iov_len - skip;
 169             skip = 0;
 170         }
 171         iov++;
 172         addr++;
 173         num--;
 174     }
 175
 176     assert(skip == 0);
 177     return copied;
 178 }
 179
 180 static int virtio_scsi_parse_req(VirtIOSCSIReq *req,
 181                                  unsigned req_size, unsigned resp_size)
 182 {
 183     VirtIODevice *vdev = (VirtIODevice *) req->dev;
 184     size_t in_size, out_size;
 185
 186     if (iov_to_buf(req->elem.out_sg, req->elem.out_num, 0,
 187                    &req->req, req_size) < req_size) {
 188         return -EINVAL;
 189     }
 190
 191     if (qemu_iovec_concat_iov(&req->resp_iov,
 192                               req->elem.in_sg, req->elem.in_num, 0,
 193                               resp_size) < resp_size) {
 194         return -EINVAL;
 195     }
 196
 197     req->resp_size = resp_size;
 198
 199     /* Old BIOSes left some padding by mistake after the req_size/resp_size.
 200      * As a workaround, always consider the first buffer as the virtio-scsi
 201      * request/response, making the payload start at the second element
 202      * of the iovec.
 203      *
 204      * The actual length of the response header, stored in req->resp_size,
 205      * does not change.
 206      *
 207      * TODO: always disable this workaround for virtio 1.0 devices.
 208      */
 209     if (!virtio_vdev_has_feature(vdev, VIRTIO_F_ANY_LAYOUT)) {
 210         if (req->elem.out_num) {
 211             req_size = req->elem.out_sg[0].iov_len;
 212         }
 213         if (req->elem.in_num) {
 214             resp_size = req->elem.in_sg[0].iov_len;
 215         }
 216     }
 217
 218     out_size = qemu_sgl_concat(req, req->elem.out_sg,
 219                                &req->elem.out_addr[0], req->elem.out_num,
 220                                req_size);
 221     in_size = qemu_sgl_concat(req, req->elem.in_sg,
 222                               &req->elem.in_addr[0], req->elem.in_num,
 223                               resp_size);
 224
 225     if (out_size && in_size) {
 226         return -ENOTSUP;
 227     }
 228
 229     if (out_size) {
 230         req->mode = SCSI_XFER_TO_DEV;
 231     } else if (in_size) {
 232         req->mode = SCSI_XFER_FROM_DEV;
 233     }
 234
 235     return 0;
 236 }
 237
 238 static VirtIOSCSIReq *virtio_scsi_pop_req(VirtIOSCSI *s, VirtQueue *vq)
 239 {
 240     VirtIOSCSICommon *vs = (VirtIOSCSICommon *)s;
 241     VirtIOSCSIReq *req;
 242
 243     req = virtqueue_pop(vq, sizeof(VirtIOSCSIReq) + vs->cdb_size);
 244     if (!req) {
 245         return NULL;
 246     }
 247     virtio_scsi_init_req(s, vq, req);
 248     return req;
 249 }
 250
 251 static void virtio_scsi_save_request(QEMUFile *f, SCSIRequest *sreq)
 252 {
 253     VirtIOSCSIReq *req = sreq->hba_private;
 254     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(req->dev);
 255     VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
 256     uint32_t n = virtio_get_queue_index(req->vq) - VIRTIO_SCSI_VQ_NUM_FIXED;
 257
 258     assert(n < vs->conf.num_queues);
 259     qemu_put_be32s(f, &n);
 260     qemu_put_virtqueue_element(vdev, f, &req->elem);
 261 }
 262
 263 static void *virtio_scsi_load_request(QEMUFile *f, SCSIRequest *sreq)
 264 {
 265     SCSIBus *bus = sreq->bus;
 266     VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
 267     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
 268     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 269     VirtIOSCSIReq *req;
 270     uint32_t n;
 271
 272     qemu_get_be32s(f, &n);
 273     assert(n < vs->conf.num_queues);
 274     req = qemu_get_virtqueue_element(vdev, f,
 275                                      sizeof(VirtIOSCSIReq) + vs->cdb_size);
 276     virtio_scsi_init_req(s, vs->cmd_vqs[n], req);
 277
 278     if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICmdReq) + vs->cdb_size,
 279                               sizeof(VirtIOSCSICmdResp) + vs->sense_size) < 0) {
 280         error_report("invalid SCSI request migration data");
 281         exit(1);
 282     }
 283
 284     scsi_req_ref(sreq);
 285     req->sreq = sreq;
 286     if (req->sreq->cmd.mode != SCSI_XFER_NONE) {
 287         assert(req->sreq->cmd.mode == req->mode);
 288     }
 289     return req;
 290 }
 291
 292 typedef struct {
 293     Notifier        notifier;
 294     VirtIOSCSIReq  *tmf_req;
 295 } VirtIOSCSICancelNotifier;
 296
 297 static void virtio_scsi_cancel_notify(Notifier *notifier, void *data)
 298 {
 299     VirtIOSCSICancelNotifier *n = container_of(notifier,
 300                                                VirtIOSCSICancelNotifier,
 301                                                notifier);
 302
 303     if (--n->tmf_req->remaining == 0) {
 304         VirtIOSCSIReq *req = n->tmf_req;
 305
 306         trace_virtio_scsi_tmf_resp(virtio_scsi_get_lun(req->req.tmf.lun),
 307                                    req->req.tmf.tag, req->resp.tmf.response);
 308         virtio_scsi_complete_req(req);
 309     }
 310     g_free(n);
 311 }
 312
 313 static inline void virtio_scsi_ctx_check(VirtIOSCSI *s, SCSIDevice *d)
 314 {
 315     if (s->dataplane_started && d && blk_is_available(d->conf.blk)) {
 316         assert(blk_get_aio_context(d->conf.blk) == s->ctx);
 317     }
 318 }
 319
 320 static void virtio_scsi_do_one_tmf_bh(VirtIOSCSIReq *req)
 321 {
 322     VirtIOSCSI *s = req->dev;
 323     SCSIDevice *d = virtio_scsi_device_get(s, req->req.tmf.lun);
 324     BusChild *kid;
 325     int target;
 326
 327     switch (req->req.tmf.subtype) {
 328     case VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET:
 329         if (!d) {
 330             req->resp.tmf.response = VIRTIO_SCSI_S_BAD_TARGET;
 331             goto out;
 332         }
 333         if (d->lun != virtio_scsi_get_lun(req->req.tmf.lun)) {
 334             req->resp.tmf.response = VIRTIO_SCSI_S_INCORRECT_LUN;
 335             goto out;
 336         }
 337         qatomic_inc(&s->resetting);
 338         device_cold_reset(&d->qdev);
 339         qatomic_dec(&s->resetting);
 340         break;
 341
 342     case VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET:
 343         target = req->req.tmf.lun[1];
 344         qatomic_inc(&s->resetting);
 345
 346         rcu_read_lock();
 347         QTAILQ_FOREACH_RCU(kid, &s->bus.qbus.children, sibling) {
 348             SCSIDevice *d1 = SCSI_DEVICE(kid->child);
 349             if (d1->channel == 0 && d1->id == target) {
 350                 device_cold_reset(&d1->qdev);
 351             }
 352         }
 353         rcu_read_unlock();
 354
 355         qatomic_dec(&s->resetting);
 356         break;
 357
 358     default:
 359         g_assert_not_reached();
 360         break;
 361     }
 362
 363 out:
 364     object_unref(OBJECT(d));
 365     virtio_scsi_complete_req_from_main_loop(req);
 366 }
 367
 368 /* Some TMFs must be processed from the main loop thread */
 369 static void virtio_scsi_do_tmf_bh(void *opaque)
 370 {
 371     VirtIOSCSI *s = opaque;
 372     QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs);
 373     VirtIOSCSIReq *req;
 374     VirtIOSCSIReq *tmp;
 375
 376     GLOBAL_STATE_CODE();
 377
 378     WITH_QEMU_LOCK_GUARD(&s->tmf_bh_lock) {
 379         QTAILQ_FOREACH_SAFE(req, &s->tmf_bh_list, next, tmp) {
 380             QTAILQ_REMOVE(&s->tmf_bh_list, req, next);
 381             QTAILQ_INSERT_TAIL(&reqs, req, next);
 382         }
 383
 384         qemu_bh_delete(s->tmf_bh);
 385         s->tmf_bh = NULL;
 386     }
 387
 388     QTAILQ_FOREACH_SAFE(req, &reqs, next, tmp) {
 389         QTAILQ_REMOVE(&reqs, req, next);
 390         virtio_scsi_do_one_tmf_bh(req);
 391     }
 392 }
 393
 394 static void virtio_scsi_reset_tmf_bh(VirtIOSCSI *s)
 395 {
 396     VirtIOSCSIReq *req;
 397     VirtIOSCSIReq *tmp;
 398
 399     GLOBAL_STATE_CODE();
 400
 401     /* Called after ioeventfd has been stopped, so tmf_bh_lock is not needed */
 402     if (s->tmf_bh) {
 403         qemu_bh_delete(s->tmf_bh);
 404         s->tmf_bh = NULL;
 405     }
 406
 407     QTAILQ_FOREACH_SAFE(req, &s->tmf_bh_list, next, tmp) {
 408         QTAILQ_REMOVE(&s->tmf_bh_list, req, next);
 409
 410         /* SAM-6 6.3.2 Hard reset */
 411         req->resp.tmf.response = VIRTIO_SCSI_S_TARGET_FAILURE;
 412         virtio_scsi_complete_req(req);
 413     }
 414 }
 415
 416 static void virtio_scsi_defer_tmf_to_bh(VirtIOSCSIReq *req)
 417 {
 418     VirtIOSCSI *s = req->dev;
 419
 420     WITH_QEMU_LOCK_GUARD(&s->tmf_bh_lock) {
 421         QTAILQ_INSERT_TAIL(&s->tmf_bh_list, req, next);
 422
 423         if (!s->tmf_bh) {
 424             s->tmf_bh = qemu_bh_new(virtio_scsi_do_tmf_bh, s);
 425             qemu_bh_schedule(s->tmf_bh);
 426         }
 427     }
 428 }
 429
 430 /* Return 0 if the request is ready to be completed and return to guest;
 431  * -EINPROGRESS if the request is submitted and will be completed later, in the
 432  *  case of async cancellation. */
 433 static int virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req)
 434 {
 435     SCSIDevice *d = virtio_scsi_device_get(s, req->req.tmf.lun);
 436     SCSIRequest *r, *next;
 437     int ret = 0;
 438
 439     virtio_scsi_ctx_check(s, d);
 440     /* Here VIRTIO_SCSI_S_OK means "FUNCTION COMPLETE".  */
 441     req->resp.tmf.response = VIRTIO_SCSI_S_OK;
 442
 443     /*
 444      * req->req.tmf has the QEMU_PACKED attribute. Don't use virtio_tswap32s()
 445      * to avoid compiler errors.
 446      */
 447     req->req.tmf.subtype =
 448         virtio_tswap32(VIRTIO_DEVICE(s), req->req.tmf.subtype);
 449
 450     trace_virtio_scsi_tmf_req(virtio_scsi_get_lun(req->req.tmf.lun),
 451                               req->req.tmf.tag, req->req.tmf.subtype);
 452
 453     switch (req->req.tmf.subtype) {
 454     case VIRTIO_SCSI_T_TMF_ABORT_TASK:
 455     case VIRTIO_SCSI_T_TMF_QUERY_TASK:
 456         if (!d) {
 457             goto fail;
 458         }
 459         if (d->lun != virtio_scsi_get_lun(req->req.tmf.lun)) {
 460             goto incorrect_lun;
 461         }
 462         QTAILQ_FOREACH_SAFE(r, &d->requests, next, next) {
 463             VirtIOSCSIReq *cmd_req = r->hba_private;
 464             if (cmd_req && cmd_req->req.cmd.tag == req->req.tmf.tag) {
 465                 break;
 466             }
 467         }
 468         if (r) {
 469             /*
 470              * Assert that the request has not been completed yet, we
 471              * check for it in the loop above.
 472              */
 473             assert(r->hba_private);
 474             if (req->req.tmf.subtype == VIRTIO_SCSI_T_TMF_QUERY_TASK) {
 475                 /* "If the specified command is present in the task set, then
 476                  * return a service response set to FUNCTION SUCCEEDED".
 477                  */
 478                 req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
 479             } else {
 480                 VirtIOSCSICancelNotifier *notifier;
 481
 482                 req->remaining = 1;
 483                 notifier = g_new(VirtIOSCSICancelNotifier, 1);
 484                 notifier->tmf_req = req;
 485                 notifier->notifier.notify = virtio_scsi_cancel_notify;
 486                 scsi_req_cancel_async(r, &notifier->notifier);
 487                 ret = -EINPROGRESS;
 488             }
 489         }
 490         break;
 491
 492     case VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET:
 493     case VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET:
 494         virtio_scsi_defer_tmf_to_bh(req);
 495         ret = -EINPROGRESS;
 496         break;
 497
 498     case VIRTIO_SCSI_T_TMF_ABORT_TASK_SET:
 499     case VIRTIO_SCSI_T_TMF_CLEAR_TASK_SET:
 500     case VIRTIO_SCSI_T_TMF_QUERY_TASK_SET:
 501         if (!d) {
 502             goto fail;
 503         }
 504         if (d->lun != virtio_scsi_get_lun(req->req.tmf.lun)) {
 505             goto incorrect_lun;
 506         }
 507
 508         /* Add 1 to "remaining" until virtio_scsi_do_tmf returns.
 509          * This way, if the bus starts calling back to the notifiers
 510          * even before we finish the loop, virtio_scsi_cancel_notify
 511          * will not complete the TMF too early.
 512          */
 513         req->remaining = 1;
 514         QTAILQ_FOREACH_SAFE(r, &d->requests, next, next) {
 515             if (r->hba_private) {
 516                 if (req->req.tmf.subtype == VIRTIO_SCSI_T_TMF_QUERY_TASK_SET) {
 517                     /* "If there is any command present in the task set, then
 518                      * return a service response set to FUNCTION SUCCEEDED".
 519                      */
 520                     req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
 521                     break;
 522                 } else {
 523                     VirtIOSCSICancelNotifier *notifier;
 524
 525                     req->remaining++;
 526                     notifier = g_new(VirtIOSCSICancelNotifier, 1);
 527                     notifier->notifier.notify = virtio_scsi_cancel_notify;
 528                     notifier->tmf_req = req;
 529                     scsi_req_cancel_async(r, &notifier->notifier);
 530                 }
 531             }
 532         }
 533         if (--req->remaining > 0) {
 534             ret = -EINPROGRESS;
 535         }
 536         break;
 537
 538     case VIRTIO_SCSI_T_TMF_CLEAR_ACA:
 539     default:
 540         req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_REJECTED;
 541         break;
 542     }
 543
 544     object_unref(OBJECT(d));
 545     return ret;
 546
 547 incorrect_lun:
 548     req->resp.tmf.response = VIRTIO_SCSI_S_INCORRECT_LUN;
 549     object_unref(OBJECT(d));
 550     return ret;
 551
 552 fail:
 553     req->resp.tmf.response = VIRTIO_SCSI_S_BAD_TARGET;
 554     object_unref(OBJECT(d));
 555     return ret;
 556 }
 557
 558 static void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s, VirtIOSCSIReq *req)
 559 {
 560     VirtIODevice *vdev = (VirtIODevice *)s;
 561     uint32_t type;
 562     int r = 0;
 563
 564     if (iov_to_buf(req->elem.out_sg, req->elem.out_num, 0,
 565                 &type, sizeof(type)) < sizeof(type)) {
 566         virtio_scsi_bad_req(req);
 567         return;
 568     }
 569
 570     virtio_tswap32s(vdev, &type);
 571     if (type == VIRTIO_SCSI_T_TMF) {
 572         if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICtrlTMFReq),
 573                     sizeof(VirtIOSCSICtrlTMFResp)) < 0) {
 574             virtio_scsi_bad_req(req);
 575             return;
 576         } else {
 577             r = virtio_scsi_do_tmf(s, req);
 578         }
 579
 580     } else if (type == VIRTIO_SCSI_T_AN_QUERY ||
 581                type == VIRTIO_SCSI_T_AN_SUBSCRIBE) {
 582         if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICtrlANReq),
 583                     sizeof(VirtIOSCSICtrlANResp)) < 0) {
 584             virtio_scsi_bad_req(req);
 585             return;
 586         } else {
 587             req->req.an.event_requested =
 588                 virtio_tswap32(VIRTIO_DEVICE(s), req->req.an.event_requested);
 589             trace_virtio_scsi_an_req(virtio_scsi_get_lun(req->req.an.lun),
 590                                      req->req.an.event_requested);
 591             req->resp.an.event_actual = 0;
 592             req->resp.an.response = VIRTIO_SCSI_S_OK;
 593         }
 594     }
 595     if (r == 0) {
 596         if (type == VIRTIO_SCSI_T_TMF)
 597             trace_virtio_scsi_tmf_resp(virtio_scsi_get_lun(req->req.tmf.lun),
 598                                        req->req.tmf.tag,
 599                                        req->resp.tmf.response);
 600         else if (type == VIRTIO_SCSI_T_AN_QUERY ||
 601                  type == VIRTIO_SCSI_T_AN_SUBSCRIBE)
 602             trace_virtio_scsi_an_resp(virtio_scsi_get_lun(req->req.an.lun),
 603                                       req->resp.an.response);
 604         virtio_scsi_complete_req(req);
 605     } else {
 606         assert(r == -EINPROGRESS);
 607     }
 608 }
 609
 610 static void virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq)
 611 {
 612     VirtIOSCSIReq *req;
 613
 614     while ((req = virtio_scsi_pop_req(s, vq))) {
 615         virtio_scsi_handle_ctrl_req(s, req);
 616     }
 617 }
 618
 619 /*
 620  * If dataplane is configured but not yet started, do so now and return true on
 621  * success.
 622  *
 623  * Dataplane is started by the core virtio code but virtqueue handler functions
 624  * can also be invoked when a guest kicks before DRIVER_OK, so this helper
 625  * function helps us deal with manually starting ioeventfd in that case.
 626  */
 627 static bool virtio_scsi_defer_to_dataplane(VirtIOSCSI *s)
 628 {
 629     if (!s->ctx || s->dataplane_started) {
 630         return false;
 631     }
 632
 633     virtio_device_start_ioeventfd(&s->parent_obj.parent_obj);
 634     return !s->dataplane_fenced;
 635 }
 636
 637 static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
 638 {
 639     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
 640
 641     if (virtio_scsi_defer_to_dataplane(s)) {
 642         return;
 643     }
 644
 645     virtio_scsi_handle_ctrl_vq(s, vq);
 646 }
 647
 648 static void virtio_scsi_complete_cmd_req(VirtIOSCSIReq *req)
 649 {
 650     trace_virtio_scsi_cmd_resp(virtio_scsi_get_lun(req->req.cmd.lun),
 651                                req->req.cmd.tag,
 652                                req->resp.cmd.response,
 653                                req->resp.cmd.status);
 654     /* Sense data is not in req->resp and is copied separately
 655      * in virtio_scsi_command_complete.
 656      */
 657     req->resp_size = sizeof(VirtIOSCSICmdResp);
 658     virtio_scsi_complete_req(req);
 659 }
 660
 661 static void virtio_scsi_command_failed(SCSIRequest *r)
 662 {
 663     VirtIOSCSIReq *req = r->hba_private;
 664
 665     if (r->io_canceled) {
 666         return;
 667     }
 668
 669     req->resp.cmd.status = GOOD;
 670     switch (r->host_status) {
 671     case SCSI_HOST_NO_LUN:
 672         req->resp.cmd.response = VIRTIO_SCSI_S_INCORRECT_LUN;
 673         break;
 674     case SCSI_HOST_BUSY:
 675         req->resp.cmd.response = VIRTIO_SCSI_S_BUSY;
 676         break;
 677     case SCSI_HOST_TIME_OUT:
 678     case SCSI_HOST_ABORTED:
 679         req->resp.cmd.response = VIRTIO_SCSI_S_ABORTED;
 680         break;
 681     case SCSI_HOST_BAD_RESPONSE:
 682         req->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
 683         break;
 684     case SCSI_HOST_RESET:
 685         req->resp.cmd.response = VIRTIO_SCSI_S_RESET;
 686         break;
 687     case SCSI_HOST_TRANSPORT_DISRUPTED:
 688         req->resp.cmd.response = VIRTIO_SCSI_S_TRANSPORT_FAILURE;
 689         break;
 690     case SCSI_HOST_TARGET_FAILURE:
 691         req->resp.cmd.response = VIRTIO_SCSI_S_TARGET_FAILURE;
 692         break;
 693     case SCSI_HOST_RESERVATION_ERROR:
 694         req->resp.cmd.response = VIRTIO_SCSI_S_NEXUS_FAILURE;
 695         break;
 696     case SCSI_HOST_ALLOCATION_FAILURE:
 697     case SCSI_HOST_MEDIUM_ERROR:
 698     case SCSI_HOST_ERROR:
 699     default:
 700         req->resp.cmd.response = VIRTIO_SCSI_S_FAILURE;
 701         break;
 702     }
 703     virtio_scsi_complete_cmd_req(req);
 704 }
 705
 706 static void virtio_scsi_command_complete(SCSIRequest *r, size_t resid)
 707 {
 708     VirtIOSCSIReq *req = r->hba_private;
 709     uint8_t sense[SCSI_SENSE_BUF_SIZE];
 710     uint32_t sense_len;
 711     VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
 712
 713     if (r->io_canceled) {
 714         return;
 715     }
 716
 717     req->resp.cmd.response = VIRTIO_SCSI_S_OK;
 718     req->resp.cmd.status = r->status;
 719     if (req->resp.cmd.status == GOOD) {
 720         req->resp.cmd.resid = virtio_tswap32(vdev, resid);
 721     } else {
 722         req->resp.cmd.resid = 0;
 723         sense_len = scsi_req_get_sense(r, sense, sizeof(sense));
 724         sense_len = MIN(sense_len, req->resp_iov.size - sizeof(req->resp.cmd));
 725         qemu_iovec_from_buf(&req->resp_iov, sizeof(req->resp.cmd),
 726                             sense, sense_len);
 727         req->resp.cmd.sense_len = virtio_tswap32(vdev, sense_len);
 728     }
 729     virtio_scsi_complete_cmd_req(req);
 730 }
 731
 732 static int virtio_scsi_parse_cdb(SCSIDevice *dev, SCSICommand *cmd,
 733                                  uint8_t *buf, size_t buf_len,
 734                                  void *hba_private)
 735 {
 736     VirtIOSCSIReq *req = hba_private;
 737
 738     if (cmd->len == 0) {
 739         cmd->len = MIN(VIRTIO_SCSI_CDB_DEFAULT_SIZE, SCSI_CMD_BUF_SIZE);
 740         memcpy(cmd->buf, buf, cmd->len);
 741     }
 742
 743     /* Extract the direction and mode directly from the request, for
 744      * host device passthrough.
 745      */
 746     cmd->xfer = req->qsgl.size;
 747     cmd->mode = req->mode;
 748     return 0;
 749 }
 750
 751 static QEMUSGList *virtio_scsi_get_sg_list(SCSIRequest *r)
 752 {
 753     VirtIOSCSIReq *req = r->hba_private;
 754
 755     return &req->qsgl;
 756 }
 757
 758 static void virtio_scsi_request_cancelled(SCSIRequest *r)
 759 {
 760     VirtIOSCSIReq *req = r->hba_private;
 761
 762     if (!req) {
 763         return;
 764     }
 765     if (qatomic_read(&req->dev->resetting)) {
 766         req->resp.cmd.response = VIRTIO_SCSI_S_RESET;
 767     } else {
 768         req->resp.cmd.response = VIRTIO_SCSI_S_ABORTED;
 769     }
 770     virtio_scsi_complete_cmd_req(req);
 771 }
 772
 773 static void virtio_scsi_fail_cmd_req(VirtIOSCSIReq *req)
 774 {
 775     req->resp.cmd.response = VIRTIO_SCSI_S_FAILURE;
 776     virtio_scsi_complete_cmd_req(req);
 777 }
 778
 779 static int virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, VirtIOSCSIReq *req)
 780 {
 781     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
 782     SCSIDevice *d;
 783     int rc;
 784
 785     rc = virtio_scsi_parse_req(req, sizeof(VirtIOSCSICmdReq) + vs->cdb_size,
 786                                sizeof(VirtIOSCSICmdResp) + vs->sense_size);
 787     if (rc < 0) {
 788         if (rc == -ENOTSUP) {
 789             virtio_scsi_fail_cmd_req(req);
 790             return -ENOTSUP;
 791         } else {
 792             virtio_scsi_bad_req(req);
 793             return -EINVAL;
 794         }
 795     }
 796     trace_virtio_scsi_cmd_req(virtio_scsi_get_lun(req->req.cmd.lun),
 797                               req->req.cmd.tag, req->req.cmd.cdb[0]);
 798
 799     d = virtio_scsi_device_get(s, req->req.cmd.lun);
 800     if (!d) {
 801         req->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
 802         virtio_scsi_complete_cmd_req(req);
 803         return -ENOENT;
 804     }
 805     virtio_scsi_ctx_check(s, d);
 806     req->sreq = scsi_req_new(d, req->req.cmd.tag,
 807                              virtio_scsi_get_lun(req->req.cmd.lun),
 808                              req->req.cmd.cdb, vs->cdb_size, req);
 809
 810     if (req->sreq->cmd.mode != SCSI_XFER_NONE
 811         && (req->sreq->cmd.mode != req->mode ||
 812             req->sreq->cmd.xfer > req->qsgl.size)) {
 813         req->resp.cmd.response = VIRTIO_SCSI_S_OVERRUN;
 814         virtio_scsi_complete_cmd_req(req);
 815         object_unref(OBJECT(d));
 816         return -ENOBUFS;
 817     }
 818     scsi_req_ref(req->sreq);
 819     defer_call_begin();
 820     object_unref(OBJECT(d));
 821     return 0;
 822 }
 823
 824 static void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI *s, VirtIOSCSIReq *req)
 825 {
 826     SCSIRequest *sreq = req->sreq;
 827     if (scsi_req_enqueue(sreq)) {
 828         scsi_req_continue(sreq);
 829     }
 830     defer_call_end();
 831     scsi_req_unref(sreq);
 832 }
 833
 834 static void virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
 835 {
 836     VirtIOSCSIReq *req, *next;
 837     int ret = 0;
 838     bool suppress_notifications = virtio_queue_get_notification(vq);
 839
 840     QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs);
 841
 842     do {
 843         if (suppress_notifications) {
 844             virtio_queue_set_notification(vq, 0);
 845         }
 846
 847         while ((req = virtio_scsi_pop_req(s, vq))) {
 848             ret = virtio_scsi_handle_cmd_req_prepare(s, req);
 849             if (!ret) {
 850                 QTAILQ_INSERT_TAIL(&reqs, req, next);
 851             } else if (ret == -EINVAL) {
 852                 /* The device is broken and shouldn't process any request */
 853                 while (!QTAILQ_EMPTY(&reqs)) {
 854                     req = QTAILQ_FIRST(&reqs);
 855                     QTAILQ_REMOVE(&reqs, req, next);
 856                     defer_call_end();
 857                     scsi_req_unref(req->sreq);
 858                     virtqueue_detach_element(req->vq, &req->elem, 0);
 859                     virtio_scsi_free_req(req);
 860                 }
 861             }
 862         }
 863
 864         if (suppress_notifications) {
 865             virtio_queue_set_notification(vq, 1);
 866         }
 867     } while (ret != -EINVAL && !virtio_queue_empty(vq));
 868
 869     QTAILQ_FOREACH_SAFE(req, &reqs, next, next) {
 870         virtio_scsi_handle_cmd_req_submit(s, req);
 871     }
 872 }
 873
 874 static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)
 875 {
 876     /* use non-QOM casts in the data path */
 877     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
 878
 879     if (virtio_scsi_defer_to_dataplane(s)) {
 880         return;
 881     }
 882
 883     virtio_scsi_handle_cmd_vq(s, vq);
 884 }
 885
 886 static void virtio_scsi_get_config(VirtIODevice *vdev,
 887                                    uint8_t *config)
 888 {
 889     VirtIOSCSIConfig *scsiconf = (VirtIOSCSIConfig *)config;
 890     VirtIOSCSICommon *s = VIRTIO_SCSI_COMMON(vdev);
 891
 892     virtio_stl_p(vdev, &scsiconf->num_queues, s->conf.num_queues);
 893     virtio_stl_p(vdev, &scsiconf->seg_max,
 894                  s->conf.seg_max_adjust ? s->conf.virtqueue_size - 2 : 128 - 2);
 895     virtio_stl_p(vdev, &scsiconf->max_sectors, s->conf.max_sectors);
 896     virtio_stl_p(vdev, &scsiconf->cmd_per_lun, s->conf.cmd_per_lun);
 897     virtio_stl_p(vdev, &scsiconf->event_info_size, sizeof(VirtIOSCSIEvent));
 898     virtio_stl_p(vdev, &scsiconf->sense_size, s->sense_size);
 899     virtio_stl_p(vdev, &scsiconf->cdb_size, s->cdb_size);
 900     virtio_stw_p(vdev, &scsiconf->max_channel, VIRTIO_SCSI_MAX_CHANNEL);
 901     virtio_stw_p(vdev, &scsiconf->max_target, VIRTIO_SCSI_MAX_TARGET);
 902     virtio_stl_p(vdev, &scsiconf->max_lun, VIRTIO_SCSI_MAX_LUN);
 903 }
 904
 905 static void virtio_scsi_set_config(VirtIODevice *vdev,
 906                                    const uint8_t *config)
 907 {
 908     VirtIOSCSIConfig *scsiconf = (VirtIOSCSIConfig *)config;
 909     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
 910
 911     if ((uint32_t) virtio_ldl_p(vdev, &scsiconf->sense_size) >= 65536 ||
 912         (uint32_t) virtio_ldl_p(vdev, &scsiconf->cdb_size) >= 256) {
 913         virtio_error(vdev,
 914                      "bad data written to virtio-scsi configuration space");
 915         return;
 916     }
 917
 918     vs->sense_size = virtio_ldl_p(vdev, &scsiconf->sense_size);
 919     vs->cdb_size = virtio_ldl_p(vdev, &scsiconf->cdb_size);
 920 }
 921
 922 static uint64_t virtio_scsi_get_features(VirtIODevice *vdev,
 923                                          uint64_t requested_features,
 924                                          Error **errp)
 925 {
 926     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
 927
 928     /* Firstly sync all virtio-scsi possible supported features */
 929     requested_features |= s->host_features;
 930     return requested_features;
 931 }
 932
 933 static void virtio_scsi_reset(VirtIODevice *vdev)
 934 {
 935     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
 936     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
 937
 938     assert(!s->dataplane_started);
 939
 940     virtio_scsi_reset_tmf_bh(s);
 941
 942     qatomic_inc(&s->resetting);
 943     bus_cold_reset(BUS(&s->bus));
 944     qatomic_dec(&s->resetting);
 945
 946     vs->sense_size = VIRTIO_SCSI_SENSE_DEFAULT_SIZE;
 947     vs->cdb_size = VIRTIO_SCSI_CDB_DEFAULT_SIZE;
 948     s->events_dropped = false;
 949 }
 950
 951 typedef struct {
 952     uint32_t event;
 953     uint32_t reason;
 954     union {
 955         /* Used by messages specific to a device */
 956         struct {
 957             uint32_t id;
 958             uint32_t lun;
 959         } address;
 960     };
 961 } VirtIOSCSIEventInfo;
 962
 963 static void virtio_scsi_push_event(VirtIOSCSI *s,
 964                                    const VirtIOSCSIEventInfo *info)
 965 {
 966     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
 967     VirtIOSCSIReq *req;
 968     VirtIOSCSIEvent *evt;
 969     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 970     uint32_t event = info->event;
 971     uint32_t reason = info->reason;
 972
 973     if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 974         return;
 975     }
 976
 977     req = virtio_scsi_pop_req(s, vs->event_vq);
 978     if (!req) {
 979         s->events_dropped = true;
 980         return;
 981     }
 982
 983     if (s->events_dropped) {
 984         event |= VIRTIO_SCSI_T_EVENTS_MISSED;
 985         s->events_dropped = false;
 986     }
 987
 988     if (virtio_scsi_parse_req(req, 0, sizeof(VirtIOSCSIEvent))) {
 989         virtio_scsi_bad_req(req);
 990         return;
 991     }
 992
 993     evt = &req->resp.event;
 994     memset(evt, 0, sizeof(VirtIOSCSIEvent));
 995     evt->event = virtio_tswap32(vdev, event);
 996     evt->reason = virtio_tswap32(vdev, reason);
 997     if (event != VIRTIO_SCSI_T_EVENTS_MISSED) {
 998         evt->lun[0] = 1;
 999         evt->lun[1] = info->address.id;
1000
1001         /* Linux wants us to keep the same encoding we use for REPORT LUNS.  */
1002         if (info->address.lun >= 256) {
1003             evt->lun[2] = (info->address.lun >> 8) | 0x40;
1004         }
1005         evt->lun[3] = info->address.lun & 0xFF;
1006     }
1007     trace_virtio_scsi_event(virtio_scsi_get_lun(evt->lun), event, reason);
1008
1009     virtio_scsi_complete_req(req);
1010 }
1011
1012 static void virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq)
1013 {
1014     if (s->events_dropped) {
1015         VirtIOSCSIEventInfo info = {
1016             .event = VIRTIO_SCSI_T_NO_EVENT,
1017         };
1018         virtio_scsi_push_event(s, &info);
1019     }
1020 }
1021
1022 static void virtio_scsi_handle_event(VirtIODevice *vdev, VirtQueue *vq)
1023 {
1024     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
1025
1026     if (virtio_scsi_defer_to_dataplane(s)) {
1027         return;
1028     }
1029
1030     virtio_scsi_handle_event_vq(s, vq);
1031 }
1032
1033 static void virtio_scsi_change(SCSIBus *bus, SCSIDevice *dev, SCSISense sense)
1034 {
1035     VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
1036     VirtIODevice *vdev = VIRTIO_DEVICE(s);
1037
1038     if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_CHANGE) &&
1039         dev->type != TYPE_ROM) {
1040         VirtIOSCSIEventInfo info = {
1041             .event   = VIRTIO_SCSI_T_PARAM_CHANGE,
1042             .reason  = sense.asc | (sense.ascq << 8),
1043             .address = {
1044                 .id  = dev->id,
1045                 .lun = dev->lun,
1046             },
1047         };
1048
1049         virtio_scsi_push_event(s, &info);
1050     }
1051 }
1052
1053 static void virtio_scsi_pre_hotplug(HotplugHandler *hotplug_dev,
1054                                     DeviceState *dev, Error **errp)
1055 {
1056     SCSIDevice *sd = SCSI_DEVICE(dev);
1057     sd->hba_supports_iothread = true;
1058 }
1059
1060 static void virtio_scsi_hotplug(HotplugHandler *hotplug_dev, DeviceState *dev,
1061                                 Error **errp)
1062 {
1063     VirtIODevice *vdev = VIRTIO_DEVICE(hotplug_dev);
1064     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
1065     SCSIDevice *sd = SCSI_DEVICE(dev);
1066     int ret;
1067
1068     if (s->ctx && !s->dataplane_fenced) {
1069         if (blk_op_is_blocked(sd->conf.blk, BLOCK_OP_TYPE_DATAPLANE, errp)) {
1070             return;
1071         }
1072         ret = blk_set_aio_context(sd->conf.blk, s->ctx, errp);
1073         if (ret < 0) {
1074             return;
1075         }
1076     }
1077
1078     if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) {
1079         VirtIOSCSIEventInfo info = {
1080             .event   = VIRTIO_SCSI_T_TRANSPORT_RESET,
1081             .reason  = VIRTIO_SCSI_EVT_RESET_RESCAN,
1082             .address = {
1083                 .id  = sd->id,
1084                 .lun = sd->lun,
1085             },
1086         };
1087
1088         virtio_scsi_push_event(s, &info);
1089         scsi_bus_set_ua(&s->bus, SENSE_CODE(REPORTED_LUNS_CHANGED));
1090     }
1091 }
1092
1093 static void virtio_scsi_hotunplug(HotplugHandler *hotplug_dev, DeviceState *dev,
1094                                   Error **errp)
1095 {
1096     VirtIODevice *vdev = VIRTIO_DEVICE(hotplug_dev);
1097     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
1098     SCSIDevice *sd = SCSI_DEVICE(dev);
1099     VirtIOSCSIEventInfo info = {
1100         .event   = VIRTIO_SCSI_T_TRANSPORT_RESET,
1101         .reason  = VIRTIO_SCSI_EVT_RESET_REMOVED,
1102         .address = {
1103             .id  = sd->id,
1104             .lun = sd->lun,
1105         },
1106     };
1107
1108     qdev_simple_device_unplug_cb(hotplug_dev, dev, errp);
1109
1110     if (s->ctx) {
1111         /* If other users keep the BlockBackend in the iothread, that's ok */
1112         blk_set_aio_context(sd->conf.blk, qemu_get_aio_context(), NULL);
1113     }
1114
1115     if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) {
1116         virtio_scsi_push_event(s, &info);
1117         scsi_bus_set_ua(&s->bus, SENSE_CODE(REPORTED_LUNS_CHANGED));
1118     }
1119 }
1120
1121 /* Suspend virtqueue ioeventfd processing during drain */
1122 static void virtio_scsi_drained_begin(SCSIBus *bus)
1123 {
1124     VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
1125     VirtIODevice *vdev = VIRTIO_DEVICE(s);
1126     uint32_t total_queues = VIRTIO_SCSI_VQ_NUM_FIXED +
1127                             s->parent_obj.conf.num_queues;
1128
1129     /*
1130      * Drain is called when stopping dataplane but the host notifier has
1131      * already been detached. Detaching multiple times is a no-op if nothing
1132      * else is using the monitoring same file descriptor, but avoid it just in
1133      * case.
1134      *
1135      * Also, don't detach if dataplane has not even been started yet because
1136      * the host notifier isn't attached.
1137      */
1138     if (s->dataplane_stopping || !s->dataplane_started) {
1139         return;
1140     }
1141
1142     for (uint32_t i = 0; i < total_queues; i++) {
1143         VirtQueue *vq = virtio_get_queue(vdev, i);
1144         virtio_queue_aio_detach_host_notifier(vq, s->ctx);
1145     }
1146 }
1147
1148 /* Resume virtqueue ioeventfd processing after drain */
1149 static void virtio_scsi_drained_end(SCSIBus *bus)
1150 {
1151     VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
1152     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
1153     VirtIODevice *vdev = VIRTIO_DEVICE(s);
1154     uint32_t total_queues = VIRTIO_SCSI_VQ_NUM_FIXED +
1155                             s->parent_obj.conf.num_queues;
1156
1157     /*
1158      * Drain is called when stopping dataplane. Keep the host notifier detached
1159      * so it's not left dangling after dataplane is stopped.
1160      *
1161      * Also, don't attach if dataplane has not even been started yet. We're not
1162      * ready.
1163      */
1164     if (s->dataplane_stopping || !s->dataplane_started) {
1165         return;
1166     }
1167
1168     for (uint32_t i = 0; i < total_queues; i++) {
1169         VirtQueue *vq = virtio_get_queue(vdev, i);
1170         if (vq == vs->event_vq) {
1171             virtio_queue_aio_attach_host_notifier_no_poll(vq, s->ctx);
1172         } else {
1173             virtio_queue_aio_attach_host_notifier(vq, s->ctx);
1174         }
1175     }
1176 }
1177
1178 static struct SCSIBusInfo virtio_scsi_scsi_info = {
1179     .tcq = true,
1180     .max_channel = VIRTIO_SCSI_MAX_CHANNEL,
1181     .max_target = VIRTIO_SCSI_MAX_TARGET,
1182     .max_lun = VIRTIO_SCSI_MAX_LUN,
1183
1184     .complete = virtio_scsi_command_complete,
1185     .fail = virtio_scsi_command_failed,
1186     .cancel = virtio_scsi_request_cancelled,
1187     .change = virtio_scsi_change,
1188     .parse_cdb = virtio_scsi_parse_cdb,
1189     .get_sg_list = virtio_scsi_get_sg_list,
1190     .save_request = virtio_scsi_save_request,
1191     .load_request = virtio_scsi_load_request,
1192     .drained_begin = virtio_scsi_drained_begin,
1193     .drained_end = virtio_scsi_drained_end,
1194 };
1195
1196 void virtio_scsi_common_realize(DeviceState *dev,
1197                                 VirtIOHandleOutput ctrl,
1198                                 VirtIOHandleOutput evt,
1199                                 VirtIOHandleOutput cmd,
1200                                 Error **errp)
1201 {
1202     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1203     VirtIOSCSICommon *s = VIRTIO_SCSI_COMMON(dev);
1204     int i;
1205
1206     virtio_init(vdev, VIRTIO_ID_SCSI, sizeof(VirtIOSCSIConfig));
1207
1208     if (s->conf.num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
1209         s->conf.num_queues = 1;
1210     }
1211     if (s->conf.num_queues == 0 ||
1212             s->conf.num_queues > VIRTIO_QUEUE_MAX - VIRTIO_SCSI_VQ_NUM_FIXED) {
1213         error_setg(errp, "Invalid number of queues (= %" PRIu32 "), "
1214                          "must be a positive integer less than %d.",
1215                    s->conf.num_queues,
1216                    VIRTIO_QUEUE_MAX - VIRTIO_SCSI_VQ_NUM_FIXED);
1217         virtio_cleanup(vdev);
1218         return;
1219     }
1220     if (s->conf.virtqueue_size <= 2) {
1221         error_setg(errp, "invalid virtqueue_size property (= %" PRIu32 "), "
1222                    "must be > 2", s->conf.virtqueue_size);
1223         return;
1224     }
1225     s->cmd_vqs = g_new0(VirtQueue *, s->conf.num_queues);
1226     s->sense_size = VIRTIO_SCSI_SENSE_DEFAULT_SIZE;
1227     s->cdb_size = VIRTIO_SCSI_CDB_DEFAULT_SIZE;
1228
1229     s->ctrl_vq = virtio_add_queue(vdev, s->conf.virtqueue_size, ctrl);
1230     s->event_vq = virtio_add_queue(vdev, s->conf.virtqueue_size, evt);
1231     for (i = 0; i < s->conf.num_queues; i++) {
1232         s->cmd_vqs[i] = virtio_add_queue(vdev, s->conf.virtqueue_size, cmd);
1233     }
1234 }
1235
1236 static void virtio_scsi_device_realize(DeviceState *dev, Error **errp)
1237 {
1238     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1239     VirtIOSCSI *s = VIRTIO_SCSI(dev);
1240     Error *err = NULL;
1241
1242     QTAILQ_INIT(&s->tmf_bh_list);
1243     qemu_mutex_init(&s->tmf_bh_lock);
1244
1245     virtio_scsi_common_realize(dev,
1246                                virtio_scsi_handle_ctrl,
1247                                virtio_scsi_handle_event,
1248                                virtio_scsi_handle_cmd,
1249                                &err);
1250     if (err != NULL) {
1251         error_propagate(errp, err);
1252         return;
1253     }
1254
1255     scsi_bus_init_named(&s->bus, sizeof(s->bus), dev,
1256                        &virtio_scsi_scsi_info, vdev->bus_name);
1257     /* override default SCSI bus hotplug-handler, with virtio-scsi's one */
1258     qbus_set_hotplug_handler(BUS(&s->bus), OBJECT(dev));
1259
1260     virtio_scsi_dataplane_setup(s, errp);
1261 }
1262
1263 void virtio_scsi_common_unrealize(DeviceState *dev)
1264 {
1265     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1266     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(dev);
1267     int i;
1268
1269     virtio_delete_queue(vs->ctrl_vq);
1270     virtio_delete_queue(vs->event_vq);
1271     for (i = 0; i < vs->conf.num_queues; i++) {
1272         virtio_delete_queue(vs->cmd_vqs[i]);
1273     }
1274     g_free(vs->cmd_vqs);
1275     virtio_cleanup(vdev);
1276 }
1277
1278 static void virtio_scsi_device_unrealize(DeviceState *dev)
1279 {
1280     VirtIOSCSI *s = VIRTIO_SCSI(dev);
1281
1282     virtio_scsi_reset_tmf_bh(s);
1283
1284     qbus_set_hotplug_handler(BUS(&s->bus), NULL);
1285     virtio_scsi_common_unrealize(dev);
1286     qemu_mutex_destroy(&s->tmf_bh_lock);
1287 }
1288
1289 static Property virtio_scsi_properties[] = {
1290     DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues,
1291                        VIRTIO_SCSI_AUTO_NUM_QUEUES),
1292     DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSI,
1293                                          parent_obj.conf.virtqueue_size, 256),
1294     DEFINE_PROP_BOOL("seg_max_adjust", VirtIOSCSI,
1295                       parent_obj.conf.seg_max_adjust, true),
1296     DEFINE_PROP_UINT32("max_sectors", VirtIOSCSI, parent_obj.conf.max_sectors,
1297                                                   0xFFFF),
1298     DEFINE_PROP_UINT32("cmd_per_lun", VirtIOSCSI, parent_obj.conf.cmd_per_lun,
1299                                                   128),
1300     DEFINE_PROP_BIT("hotplug", VirtIOSCSI, host_features,
1301                                            VIRTIO_SCSI_F_HOTPLUG, true),
1302     DEFINE_PROP_BIT("param_change", VirtIOSCSI, host_features,
1303                                                 VIRTIO_SCSI_F_CHANGE, true),
1304     DEFINE_PROP_LINK("iothread", VirtIOSCSI, parent_obj.conf.iothread,
1305                      TYPE_IOTHREAD, IOThread *),
1306     DEFINE_PROP_END_OF_LIST(),
1307 };
1308
1309 static const VMStateDescription vmstate_virtio_scsi = {
1310     .name = "virtio-scsi",
1311     .minimum_version_id = 1,
1312     .version_id = 1,
1313     .fields = (const VMStateField[]) {
1314         VMSTATE_VIRTIO_DEVICE,
1315         VMSTATE_END_OF_LIST()
1316     },
1317 };
1318
1319 static void virtio_scsi_common_class_init(ObjectClass *klass, void *data)
1320 {
1321     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
1322     DeviceClass *dc = DEVICE_CLASS(klass);
1323
1324     vdc->get_config = virtio_scsi_get_config;
1325     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
1326 }
1327
1328 static void virtio_scsi_class_init(ObjectClass *klass, void *data)
1329 {
1330     DeviceClass *dc = DEVICE_CLASS(klass);
1331     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
1332     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
1333
1334     device_class_set_props(dc, virtio_scsi_properties);
1335     dc->vmsd = &vmstate_virtio_scsi;
1336     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
1337     vdc->realize = virtio_scsi_device_realize;
1338     vdc->unrealize = virtio_scsi_device_unrealize;
1339     vdc->set_config = virtio_scsi_set_config;
1340     vdc->get_features = virtio_scsi_get_features;
1341     vdc->reset = virtio_scsi_reset;
1342     vdc->start_ioeventfd = virtio_scsi_dataplane_start;
1343     vdc->stop_ioeventfd = virtio_scsi_dataplane_stop;
1344     hc->pre_plug = virtio_scsi_pre_hotplug;
1345     hc->plug = virtio_scsi_hotplug;
1346     hc->unplug = virtio_scsi_hotunplug;
1347 }
1348
1349 static const TypeInfo virtio_scsi_common_info = {
1350     .name = TYPE_VIRTIO_SCSI_COMMON,
1351     .parent = TYPE_VIRTIO_DEVICE,
1352     .instance_size = sizeof(VirtIOSCSICommon),
1353     .abstract = true,
1354     .class_init = virtio_scsi_common_class_init,
1355 };
1356
1357 static const TypeInfo virtio_scsi_info = {
1358     .name = TYPE_VIRTIO_SCSI,
1359     .parent = TYPE_VIRTIO_SCSI_COMMON,
1360     .instance_size = sizeof(VirtIOSCSI),
1361     .class_init = virtio_scsi_class_init,
1362     .interfaces = (InterfaceInfo[]) {
1363         { TYPE_HOTPLUG_HANDLER },
1364         { }
1365     }
1366 };
1367
1368 static void virtio_register_types(void)
1369 {
1370     type_register_static(&virtio_scsi_common_info);
1371     type_register_static(&virtio_scsi_info);
1372 }
1373
1374 type_init(virtio_register_types)