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     }
 361
 362 out:
 363     object_unref(OBJECT(d));
 364     virtio_scsi_complete_req_from_main_loop(req);
 365 }
 366
 367 /* Some TMFs must be processed from the main loop thread */
 368 static void virtio_scsi_do_tmf_bh(void *opaque)
 369 {
 370     VirtIOSCSI *s = opaque;
 371     QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs);
 372     VirtIOSCSIReq *req;
 373     VirtIOSCSIReq *tmp;
 374
 375     GLOBAL_STATE_CODE();
 376
 377     WITH_QEMU_LOCK_GUARD(&s->tmf_bh_lock) {
 378         QTAILQ_FOREACH_SAFE(req, &s->tmf_bh_list, next, tmp) {
 379             QTAILQ_REMOVE(&s->tmf_bh_list, req, next);
 380             QTAILQ_INSERT_TAIL(&reqs, req, next);
 381         }
 382
 383         qemu_bh_delete(s->tmf_bh);
 384         s->tmf_bh = NULL;
 385     }
 386
 387     QTAILQ_FOREACH_SAFE(req, &reqs, next, tmp) {
 388         QTAILQ_REMOVE(&reqs, req, next);
 389         virtio_scsi_do_one_tmf_bh(req);
 390     }
 391 }
 392
 393 static void virtio_scsi_reset_tmf_bh(VirtIOSCSI *s)
 394 {
 395     VirtIOSCSIReq *req;
 396     VirtIOSCSIReq *tmp;
 397
 398     GLOBAL_STATE_CODE();
 399
 400     /* Called after ioeventfd has been stopped, so tmf_bh_lock is not needed */
 401     if (s->tmf_bh) {
 402         qemu_bh_delete(s->tmf_bh);
 403         s->tmf_bh = NULL;
 404     }
 405
 406     QTAILQ_FOREACH_SAFE(req, &s->tmf_bh_list, next, tmp) {
 407         QTAILQ_REMOVE(&s->tmf_bh_list, req, next);
 408
 409         /* SAM-6 6.3.2 Hard reset */
 410         req->resp.tmf.response = VIRTIO_SCSI_S_TARGET_FAILURE;
 411         virtio_scsi_complete_req(req);
 412     }
 413 }
 414
 415 static void virtio_scsi_defer_tmf_to_bh(VirtIOSCSIReq *req)
 416 {
 417     VirtIOSCSI *s = req->dev;
 418
 419     WITH_QEMU_LOCK_GUARD(&s->tmf_bh_lock) {
 420         QTAILQ_INSERT_TAIL(&s->tmf_bh_list, req, next);
 421
 422         if (!s->tmf_bh) {
 423             s->tmf_bh = qemu_bh_new(virtio_scsi_do_tmf_bh, s);
 424             qemu_bh_schedule(s->tmf_bh);
 425         }
 426     }
 427 }
 428
 429 /* Return 0 if the request is ready to be completed and return to guest;
 430  * -EINPROGRESS if the request is submitted and will be completed later, in the
 431  *  case of async cancellation. */
 432 static int virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req)
 433 {
 434     SCSIDevice *d = virtio_scsi_device_get(s, req->req.tmf.lun);
 435     SCSIRequest *r, *next;
 436     int ret = 0;
 437
 438     virtio_scsi_ctx_check(s, d);
 439     /* Here VIRTIO_SCSI_S_OK means "FUNCTION COMPLETE".  */
 440     req->resp.tmf.response = VIRTIO_SCSI_S_OK;
 441
 442     /*
 443      * req->req.tmf has the QEMU_PACKED attribute. Don't use virtio_tswap32s()
 444      * to avoid compiler errors.
 445      */
 446     req->req.tmf.subtype =
 447         virtio_tswap32(VIRTIO_DEVICE(s), req->req.tmf.subtype);
 448
 449     trace_virtio_scsi_tmf_req(virtio_scsi_get_lun(req->req.tmf.lun),
 450                               req->req.tmf.tag, req->req.tmf.subtype);
 451
 452     switch (req->req.tmf.subtype) {
 453     case VIRTIO_SCSI_T_TMF_ABORT_TASK:
 454     case VIRTIO_SCSI_T_TMF_QUERY_TASK:
 455         if (!d) {
 456             goto fail;
 457         }
 458         if (d->lun != virtio_scsi_get_lun(req->req.tmf.lun)) {
 459             goto incorrect_lun;
 460         }
 461         QTAILQ_FOREACH_SAFE(r, &d->requests, next, next) {
 462             VirtIOSCSIReq *cmd_req = r->hba_private;
 463             if (cmd_req && cmd_req->req.cmd.tag == req->req.tmf.tag) {
 464                 break;
 465             }
 466         }
 467         if (r) {
 468             /*
 469              * Assert that the request has not been completed yet, we
 470              * check for it in the loop above.
 471              */
 472             assert(r->hba_private);
 473             if (req->req.tmf.subtype == VIRTIO_SCSI_T_TMF_QUERY_TASK) {
 474                 /* "If the specified command is present in the task set, then
 475                  * return a service response set to FUNCTION SUCCEEDED".
 476                  */
 477                 req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
 478             } else {
 479                 VirtIOSCSICancelNotifier *notifier;
 480
 481                 req->remaining = 1;
 482                 notifier = g_new(VirtIOSCSICancelNotifier, 1);
 483                 notifier->tmf_req = req;
 484                 notifier->notifier.notify = virtio_scsi_cancel_notify;
 485                 scsi_req_cancel_async(r, &notifier->notifier);
 486                 ret = -EINPROGRESS;
 487             }
 488         }
 489         break;
 490
 491     case VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET:
 492     case VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET:
 493         virtio_scsi_defer_tmf_to_bh(req);
 494         ret = -EINPROGRESS;
 495         break;
 496
 497     case VIRTIO_SCSI_T_TMF_ABORT_TASK_SET:
 498     case VIRTIO_SCSI_T_TMF_CLEAR_TASK_SET:
 499     case VIRTIO_SCSI_T_TMF_QUERY_TASK_SET:
 500         if (!d) {
 501             goto fail;
 502         }
 503         if (d->lun != virtio_scsi_get_lun(req->req.tmf.lun)) {
 504             goto incorrect_lun;
 505         }
 506
 507         /* Add 1 to "remaining" until virtio_scsi_do_tmf returns.
 508          * This way, if the bus starts calling back to the notifiers
 509          * even before we finish the loop, virtio_scsi_cancel_notify
 510          * will not complete the TMF too early.
 511          */
 512         req->remaining = 1;
 513         QTAILQ_FOREACH_SAFE(r, &d->requests, next, next) {
 514             if (r->hba_private) {
 515                 if (req->req.tmf.subtype == VIRTIO_SCSI_T_TMF_QUERY_TASK_SET) {
 516                     /* "If there is any command present in the task set, then
 517                      * return a service response set to FUNCTION SUCCEEDED".
 518                      */
 519                     req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
 520                     break;
 521                 } else {
 522                     VirtIOSCSICancelNotifier *notifier;
 523
 524                     req->remaining++;
 525                     notifier = g_new(VirtIOSCSICancelNotifier, 1);
 526                     notifier->notifier.notify = virtio_scsi_cancel_notify;
 527                     notifier->tmf_req = req;
 528                     scsi_req_cancel_async(r, &notifier->notifier);
 529                 }
 530             }
 531         }
 532         if (--req->remaining > 0) {
 533             ret = -EINPROGRESS;
 534         }
 535         break;
 536
 537     case VIRTIO_SCSI_T_TMF_CLEAR_ACA:
 538     default:
 539         req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_REJECTED;
 540         break;
 541     }
 542
 543     object_unref(OBJECT(d));
 544     return ret;
 545
 546 incorrect_lun:
 547     req->resp.tmf.response = VIRTIO_SCSI_S_INCORRECT_LUN;
 548     object_unref(OBJECT(d));
 549     return ret;
 550
 551 fail:
 552     req->resp.tmf.response = VIRTIO_SCSI_S_BAD_TARGET;
 553     object_unref(OBJECT(d));
 554     return ret;
 555 }
 556
 557 static void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s, VirtIOSCSIReq *req)
 558 {
 559     VirtIODevice *vdev = (VirtIODevice *)s;
 560     uint32_t type;
 561     int r = 0;
 562
 563     if (iov_to_buf(req->elem.out_sg, req->elem.out_num, 0,
 564                 &type, sizeof(type)) < sizeof(type)) {
 565         virtio_scsi_bad_req(req);
 566         return;
 567     }
 568
 569     virtio_tswap32s(vdev, &type);
 570     if (type == VIRTIO_SCSI_T_TMF) {
 571         if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICtrlTMFReq),
 572                     sizeof(VirtIOSCSICtrlTMFResp)) < 0) {
 573             virtio_scsi_bad_req(req);
 574             return;
 575         } else {
 576             r = virtio_scsi_do_tmf(s, req);
 577         }
 578
 579     } else if (type == VIRTIO_SCSI_T_AN_QUERY ||
 580                type == VIRTIO_SCSI_T_AN_SUBSCRIBE) {
 581         if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICtrlANReq),
 582                     sizeof(VirtIOSCSICtrlANResp)) < 0) {
 583             virtio_scsi_bad_req(req);
 584             return;
 585         } else {
 586             req->req.an.event_requested =
 587                 virtio_tswap32(VIRTIO_DEVICE(s), req->req.an.event_requested);
 588             trace_virtio_scsi_an_req(virtio_scsi_get_lun(req->req.an.lun),
 589                                      req->req.an.event_requested);
 590             req->resp.an.event_actual = 0;
 591             req->resp.an.response = VIRTIO_SCSI_S_OK;
 592         }
 593     }
 594     if (r == 0) {
 595         if (type == VIRTIO_SCSI_T_TMF)
 596             trace_virtio_scsi_tmf_resp(virtio_scsi_get_lun(req->req.tmf.lun),
 597                                        req->req.tmf.tag,
 598                                        req->resp.tmf.response);
 599         else if (type == VIRTIO_SCSI_T_AN_QUERY ||
 600                  type == VIRTIO_SCSI_T_AN_SUBSCRIBE)
 601             trace_virtio_scsi_an_resp(virtio_scsi_get_lun(req->req.an.lun),
 602                                       req->resp.an.response);
 603         virtio_scsi_complete_req(req);
 604     } else {
 605         assert(r == -EINPROGRESS);
 606     }
 607 }
 608
 609 static void virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq)
 610 {
 611     VirtIOSCSIReq *req;
 612
 613     while ((req = virtio_scsi_pop_req(s, vq))) {
 614         virtio_scsi_handle_ctrl_req(s, req);
 615     }
 616 }
 617
 618 /*
 619  * If dataplane is configured but not yet started, do so now and return true on
 620  * success.
 621  *
 622  * Dataplane is started by the core virtio code but virtqueue handler functions
 623  * can also be invoked when a guest kicks before DRIVER_OK, so this helper
 624  * function helps us deal with manually starting ioeventfd in that case.
 625  */
 626 static bool virtio_scsi_defer_to_dataplane(VirtIOSCSI *s)
 627 {
 628     if (!s->ctx || s->dataplane_started) {
 629         return false;
 630     }
 631
 632     virtio_device_start_ioeventfd(&s->parent_obj.parent_obj);
 633     return !s->dataplane_fenced;
 634 }
 635
 636 static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
 637 {
 638     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
 639
 640     if (virtio_scsi_defer_to_dataplane(s)) {
 641         return;
 642     }
 643
 644     virtio_scsi_handle_ctrl_vq(s, vq);
 645 }
 646
 647 static void virtio_scsi_complete_cmd_req(VirtIOSCSIReq *req)
 648 {
 649     trace_virtio_scsi_cmd_resp(virtio_scsi_get_lun(req->req.cmd.lun),
 650                                req->req.cmd.tag,
 651                                req->resp.cmd.response,
 652                                req->resp.cmd.status);
 653     /* Sense data is not in req->resp and is copied separately
 654      * in virtio_scsi_command_complete.
 655      */
 656     req->resp_size = sizeof(VirtIOSCSICmdResp);
 657     virtio_scsi_complete_req(req);
 658 }
 659
 660 static void virtio_scsi_command_failed(SCSIRequest *r)
 661 {
 662     VirtIOSCSIReq *req = r->hba_private;
 663
 664     if (r->io_canceled) {
 665         return;
 666     }
 667
 668     req->resp.cmd.status = GOOD;
 669     switch (r->host_status) {
 670     case SCSI_HOST_NO_LUN:
 671         req->resp.cmd.response = VIRTIO_SCSI_S_INCORRECT_LUN;
 672         break;
 673     case SCSI_HOST_BUSY:
 674         req->resp.cmd.response = VIRTIO_SCSI_S_BUSY;
 675         break;
 676     case SCSI_HOST_TIME_OUT:
 677     case SCSI_HOST_ABORTED:
 678         req->resp.cmd.response = VIRTIO_SCSI_S_ABORTED;
 679         break;
 680     case SCSI_HOST_BAD_RESPONSE:
 681         req->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
 682         break;
 683     case SCSI_HOST_RESET:
 684         req->resp.cmd.response = VIRTIO_SCSI_S_RESET;
 685         break;
 686     case SCSI_HOST_TRANSPORT_DISRUPTED:
 687         req->resp.cmd.response = VIRTIO_SCSI_S_TRANSPORT_FAILURE;
 688         break;
 689     case SCSI_HOST_TARGET_FAILURE:
 690         req->resp.cmd.response = VIRTIO_SCSI_S_TARGET_FAILURE;
 691         break;
 692     case SCSI_HOST_RESERVATION_ERROR:
 693         req->resp.cmd.response = VIRTIO_SCSI_S_NEXUS_FAILURE;
 694         break;
 695     case SCSI_HOST_ALLOCATION_FAILURE:
 696     case SCSI_HOST_MEDIUM_ERROR:
 697     case SCSI_HOST_ERROR:
 698     default:
 699         req->resp.cmd.response = VIRTIO_SCSI_S_FAILURE;
 700         break;
 701     }
 702     virtio_scsi_complete_cmd_req(req);
 703 }
 704
 705 static void virtio_scsi_command_complete(SCSIRequest *r, size_t resid)
 706 {
 707     VirtIOSCSIReq *req = r->hba_private;
 708     uint8_t sense[SCSI_SENSE_BUF_SIZE];
 709     uint32_t sense_len;
 710     VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
 711
 712     if (r->io_canceled) {
 713         return;
 714     }
 715
 716     req->resp.cmd.response = VIRTIO_SCSI_S_OK;
 717     req->resp.cmd.status = r->status;
 718     if (req->resp.cmd.status == GOOD) {
 719         req->resp.cmd.resid = virtio_tswap32(vdev, resid);
 720     } else {
 721         req->resp.cmd.resid = 0;
 722         sense_len = scsi_req_get_sense(r, sense, sizeof(sense));
 723         sense_len = MIN(sense_len, req->resp_iov.size - sizeof(req->resp.cmd));
 724         qemu_iovec_from_buf(&req->resp_iov, sizeof(req->resp.cmd),
 725                             sense, sense_len);
 726         req->resp.cmd.sense_len = virtio_tswap32(vdev, sense_len);
 727     }
 728     virtio_scsi_complete_cmd_req(req);
 729 }
 730
 731 static int virtio_scsi_parse_cdb(SCSIDevice *dev, SCSICommand *cmd,
 732                                  uint8_t *buf, size_t buf_len,
 733                                  void *hba_private)
 734 {
 735     VirtIOSCSIReq *req = hba_private;
 736
 737     if (cmd->len == 0) {
 738         cmd->len = MIN(VIRTIO_SCSI_CDB_DEFAULT_SIZE, SCSI_CMD_BUF_SIZE);
 739         memcpy(cmd->buf, buf, cmd->len);
 740     }
 741
 742     /* Extract the direction and mode directly from the request, for
 743      * host device passthrough.
 744      */
 745     cmd->xfer = req->qsgl.size;
 746     cmd->mode = req->mode;
 747     return 0;
 748 }
 749
 750 static QEMUSGList *virtio_scsi_get_sg_list(SCSIRequest *r)
 751 {
 752     VirtIOSCSIReq *req = r->hba_private;
 753
 754     return &req->qsgl;
 755 }
 756
 757 static void virtio_scsi_request_cancelled(SCSIRequest *r)
 758 {
 759     VirtIOSCSIReq *req = r->hba_private;
 760
 761     if (!req) {
 762         return;
 763     }
 764     if (qatomic_read(&req->dev->resetting)) {
 765         req->resp.cmd.response = VIRTIO_SCSI_S_RESET;
 766     } else {
 767         req->resp.cmd.response = VIRTIO_SCSI_S_ABORTED;
 768     }
 769     virtio_scsi_complete_cmd_req(req);
 770 }
 771
 772 static void virtio_scsi_fail_cmd_req(VirtIOSCSIReq *req)
 773 {
 774     req->resp.cmd.response = VIRTIO_SCSI_S_FAILURE;
 775     virtio_scsi_complete_cmd_req(req);
 776 }
 777
 778 static int virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, VirtIOSCSIReq *req)
 779 {
 780     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
 781     SCSIDevice *d;
 782     int rc;
 783
 784     rc = virtio_scsi_parse_req(req, sizeof(VirtIOSCSICmdReq) + vs->cdb_size,
 785                                sizeof(VirtIOSCSICmdResp) + vs->sense_size);
 786     if (rc < 0) {
 787         if (rc == -ENOTSUP) {
 788             virtio_scsi_fail_cmd_req(req);
 789             return -ENOTSUP;
 790         } else {
 791             virtio_scsi_bad_req(req);
 792             return -EINVAL;
 793         }
 794     }
 795     trace_virtio_scsi_cmd_req(virtio_scsi_get_lun(req->req.cmd.lun),
 796                               req->req.cmd.tag, req->req.cmd.cdb[0]);
 797
 798     d = virtio_scsi_device_get(s, req->req.cmd.lun);
 799     if (!d) {
 800         req->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
 801         virtio_scsi_complete_cmd_req(req);
 802         return -ENOENT;
 803     }
 804     virtio_scsi_ctx_check(s, d);
 805     req->sreq = scsi_req_new(d, req->req.cmd.tag,
 806                              virtio_scsi_get_lun(req->req.cmd.lun),
 807                              req->req.cmd.cdb, vs->cdb_size, req);
 808
 809     if (req->sreq->cmd.mode != SCSI_XFER_NONE
 810         && (req->sreq->cmd.mode != req->mode ||
 811             req->sreq->cmd.xfer > req->qsgl.size)) {
 812         req->resp.cmd.response = VIRTIO_SCSI_S_OVERRUN;
 813         virtio_scsi_complete_cmd_req(req);
 814         object_unref(OBJECT(d));
 815         return -ENOBUFS;
 816     }
 817     scsi_req_ref(req->sreq);
 818     defer_call_begin();
 819     object_unref(OBJECT(d));
 820     return 0;
 821 }
 822
 823 static void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI *s, VirtIOSCSIReq *req)
 824 {
 825     SCSIRequest *sreq = req->sreq;
 826     if (scsi_req_enqueue(sreq)) {
 827         scsi_req_continue(sreq);
 828     }
 829     defer_call_end();
 830     scsi_req_unref(sreq);
 831 }
 832
 833 static void virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
 834 {
 835     VirtIOSCSIReq *req, *next;
 836     int ret = 0;
 837     bool suppress_notifications = virtio_queue_get_notification(vq);
 838
 839     QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs);
 840
 841     do {
 842         if (suppress_notifications) {
 843             virtio_queue_set_notification(vq, 0);
 844         }
 845
 846         while ((req = virtio_scsi_pop_req(s, vq))) {
 847             ret = virtio_scsi_handle_cmd_req_prepare(s, req);
 848             if (!ret) {
 849                 QTAILQ_INSERT_TAIL(&reqs, req, next);
 850             } else if (ret == -EINVAL) {
 851                 /* The device is broken and shouldn't process any request */
 852                 while (!QTAILQ_EMPTY(&reqs)) {
 853                     req = QTAILQ_FIRST(&reqs);
 854                     QTAILQ_REMOVE(&reqs, req, next);
 855                     defer_call_end();
 856                     scsi_req_unref(req->sreq);
 857                     virtqueue_detach_element(req->vq, &req->elem, 0);
 858                     virtio_scsi_free_req(req);
 859                 }
 860             }
 861         }
 862
 863         if (suppress_notifications) {
 864             virtio_queue_set_notification(vq, 1);
 865         }
 866     } while (ret != -EINVAL && !virtio_queue_empty(vq));
 867
 868     QTAILQ_FOREACH_SAFE(req, &reqs, next, next) {
 869         virtio_scsi_handle_cmd_req_submit(s, req);
 870     }
 871 }
 872
 873 static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)
 874 {
 875     /* use non-QOM casts in the data path */
 876     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
 877
 878     if (virtio_scsi_defer_to_dataplane(s)) {
 879         return;
 880     }
 881
 882     virtio_scsi_handle_cmd_vq(s, vq);
 883 }
 884
 885 static void virtio_scsi_get_config(VirtIODevice *vdev,
 886                                    uint8_t *config)
 887 {
 888     VirtIOSCSIConfig *scsiconf = (VirtIOSCSIConfig *)config;
 889     VirtIOSCSICommon *s = VIRTIO_SCSI_COMMON(vdev);
 890
 891     virtio_stl_p(vdev, &scsiconf->num_queues, s->conf.num_queues);
 892     virtio_stl_p(vdev, &scsiconf->seg_max,
 893                  s->conf.seg_max_adjust ? s->conf.virtqueue_size - 2 : 128 - 2);
 894     virtio_stl_p(vdev, &scsiconf->max_sectors, s->conf.max_sectors);
 895     virtio_stl_p(vdev, &scsiconf->cmd_per_lun, s->conf.cmd_per_lun);
 896     virtio_stl_p(vdev, &scsiconf->event_info_size, sizeof(VirtIOSCSIEvent));
 897     virtio_stl_p(vdev, &scsiconf->sense_size, s->sense_size);
 898     virtio_stl_p(vdev, &scsiconf->cdb_size, s->cdb_size);
 899     virtio_stw_p(vdev, &scsiconf->max_channel, VIRTIO_SCSI_MAX_CHANNEL);
 900     virtio_stw_p(vdev, &scsiconf->max_target, VIRTIO_SCSI_MAX_TARGET);
 901     virtio_stl_p(vdev, &scsiconf->max_lun, VIRTIO_SCSI_MAX_LUN);
 902 }
 903
 904 static void virtio_scsi_set_config(VirtIODevice *vdev,
 905                                    const uint8_t *config)
 906 {
 907     VirtIOSCSIConfig *scsiconf = (VirtIOSCSIConfig *)config;
 908     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
 909
 910     if ((uint32_t) virtio_ldl_p(vdev, &scsiconf->sense_size) >= 65536 ||
 911         (uint32_t) virtio_ldl_p(vdev, &scsiconf->cdb_size) >= 256) {
 912         virtio_error(vdev,
 913                      "bad data written to virtio-scsi configuration space");
 914         return;
 915     }
 916
 917     vs->sense_size = virtio_ldl_p(vdev, &scsiconf->sense_size);
 918     vs->cdb_size = virtio_ldl_p(vdev, &scsiconf->cdb_size);
 919 }
 920
 921 static uint64_t virtio_scsi_get_features(VirtIODevice *vdev,
 922                                          uint64_t requested_features,
 923                                          Error **errp)
 924 {
 925     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
 926
 927     /* Firstly sync all virtio-scsi possible supported features */
 928     requested_features |= s->host_features;
 929     return requested_features;
 930 }
 931
 932 static void virtio_scsi_reset(VirtIODevice *vdev)
 933 {
 934     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
 935     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
 936
 937     assert(!s->dataplane_started);
 938
 939     virtio_scsi_reset_tmf_bh(s);
 940
 941     qatomic_inc(&s->resetting);
 942     bus_cold_reset(BUS(&s->bus));
 943     qatomic_dec(&s->resetting);
 944
 945     vs->sense_size = VIRTIO_SCSI_SENSE_DEFAULT_SIZE;
 946     vs->cdb_size = VIRTIO_SCSI_CDB_DEFAULT_SIZE;
 947     s->events_dropped = false;
 948 }
 949
 950 typedef struct {
 951     uint32_t event;
 952     uint32_t reason;
 953     union {
 954         /* Used by messages specific to a device */
 955         struct {
 956             uint32_t id;
 957             uint32_t lun;
 958         } address;
 959     };
 960 } VirtIOSCSIEventInfo;
 961
 962 static void virtio_scsi_push_event(VirtIOSCSI *s,
 963                                    const VirtIOSCSIEventInfo *info)
 964 {
 965     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
 966     VirtIOSCSIReq *req;
 967     VirtIOSCSIEvent *evt;
 968     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 969     uint32_t event = info->event;
 970     uint32_t reason = info->reason;
 971
 972     if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 973         return;
 974     }
 975
 976     req = virtio_scsi_pop_req(s, vs->event_vq);
 977     if (!req) {
 978         s->events_dropped = true;
 979         return;
 980     }
 981
 982     if (s->events_dropped) {
 983         event |= VIRTIO_SCSI_T_EVENTS_MISSED;
 984         s->events_dropped = false;
 985     }
 986
 987     if (virtio_scsi_parse_req(req, 0, sizeof(VirtIOSCSIEvent))) {
 988         virtio_scsi_bad_req(req);
 989         return;
 990     }
 991
 992     evt = &req->resp.event;
 993     memset(evt, 0, sizeof(VirtIOSCSIEvent));
 994     evt->event = virtio_tswap32(vdev, event);
 995     evt->reason = virtio_tswap32(vdev, reason);
 996     if (event != VIRTIO_SCSI_T_EVENTS_MISSED) {
 997         evt->lun[0] = 1;
 998         evt->lun[1] = info->address.id;
 999
1000         /* Linux wants us to keep the same encoding we use for REPORT LUNS.  */
1001         if (info->address.lun >= 256) {
1002             evt->lun[2] = (info->address.lun >> 8) | 0x40;
1003         }
1004         evt->lun[3] = info->address.lun & 0xFF;
1005     }
1006     trace_virtio_scsi_event(virtio_scsi_get_lun(evt->lun), event, reason);
1007
1008     virtio_scsi_complete_req(req);
1009 }
1010
1011 static void virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq)
1012 {
1013     if (s->events_dropped) {
1014         VirtIOSCSIEventInfo info = {
1015             .event = VIRTIO_SCSI_T_NO_EVENT,
1016         };
1017         virtio_scsi_push_event(s, &info);
1018     }
1019 }
1020
1021 static void virtio_scsi_handle_event(VirtIODevice *vdev, VirtQueue *vq)
1022 {
1023     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
1024
1025     if (virtio_scsi_defer_to_dataplane(s)) {
1026         return;
1027     }
1028
1029     virtio_scsi_handle_event_vq(s, vq);
1030 }
1031
1032 static void virtio_scsi_change(SCSIBus *bus, SCSIDevice *dev, SCSISense sense)
1033 {
1034     VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
1035     VirtIODevice *vdev = VIRTIO_DEVICE(s);
1036
1037     if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_CHANGE) &&
1038         dev->type != TYPE_ROM) {
1039         VirtIOSCSIEventInfo info = {
1040             .event   = VIRTIO_SCSI_T_PARAM_CHANGE,
1041             .reason  = sense.asc | (sense.ascq << 8),
1042             .address = {
1043                 .id  = dev->id,
1044                 .lun = dev->lun,
1045             },
1046         };
1047
1048         virtio_scsi_push_event(s, &info);
1049     }
1050 }
1051
1052 static void virtio_scsi_pre_hotplug(HotplugHandler *hotplug_dev,
1053                                     DeviceState *dev, Error **errp)
1054 {
1055     SCSIDevice *sd = SCSI_DEVICE(dev);
1056     sd->hba_supports_iothread = true;
1057 }
1058
1059 static void virtio_scsi_hotplug(HotplugHandler *hotplug_dev, DeviceState *dev,
1060                                 Error **errp)
1061 {
1062     VirtIODevice *vdev = VIRTIO_DEVICE(hotplug_dev);
1063     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
1064     SCSIDevice *sd = SCSI_DEVICE(dev);
1065     int ret;
1066
1067     if (s->ctx && !s->dataplane_fenced) {
1068         if (blk_op_is_blocked(sd->conf.blk, BLOCK_OP_TYPE_DATAPLANE, errp)) {
1069             return;
1070         }
1071         ret = blk_set_aio_context(sd->conf.blk, s->ctx, errp);
1072         if (ret < 0) {
1073             return;
1074         }
1075     }
1076
1077     if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) {
1078         VirtIOSCSIEventInfo info = {
1079             .event   = VIRTIO_SCSI_T_TRANSPORT_RESET,
1080             .reason  = VIRTIO_SCSI_EVT_RESET_RESCAN,
1081             .address = {
1082                 .id  = sd->id,
1083                 .lun = sd->lun,
1084             },
1085         };
1086
1087         virtio_scsi_push_event(s, &info);
1088         scsi_bus_set_ua(&s->bus, SENSE_CODE(REPORTED_LUNS_CHANGED));
1089     }
1090 }
1091
1092 static void virtio_scsi_hotunplug(HotplugHandler *hotplug_dev, DeviceState *dev,
1093                                   Error **errp)
1094 {
1095     VirtIODevice *vdev = VIRTIO_DEVICE(hotplug_dev);
1096     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
1097     SCSIDevice *sd = SCSI_DEVICE(dev);
1098     VirtIOSCSIEventInfo info = {
1099         .event   = VIRTIO_SCSI_T_TRANSPORT_RESET,
1100         .reason  = VIRTIO_SCSI_EVT_RESET_REMOVED,
1101         .address = {
1102             .id  = sd->id,
1103             .lun = sd->lun,
1104         },
1105     };
1106
1107     qdev_simple_device_unplug_cb(hotplug_dev, dev, errp);
1108
1109     if (s->ctx) {
1110         /* If other users keep the BlockBackend in the iothread, that's ok */
1111         blk_set_aio_context(sd->conf.blk, qemu_get_aio_context(), NULL);
1112     }
1113
1114     if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) {
1115         virtio_scsi_push_event(s, &info);
1116         scsi_bus_set_ua(&s->bus, SENSE_CODE(REPORTED_LUNS_CHANGED));
1117     }
1118 }
1119
1120 /* Suspend virtqueue ioeventfd processing during drain */
1121 static void virtio_scsi_drained_begin(SCSIBus *bus)
1122 {
1123     VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
1124     VirtIODevice *vdev = VIRTIO_DEVICE(s);
1125     uint32_t total_queues = VIRTIO_SCSI_VQ_NUM_FIXED +
1126                             s->parent_obj.conf.num_queues;
1127
1128     /*
1129      * Drain is called when stopping dataplane but the host notifier has
1130      * already been detached. Detaching multiple times is a no-op if nothing
1131      * else is using the monitoring same file descriptor, but avoid it just in
1132      * case.
1133      *
1134      * Also, don't detach if dataplane has not even been started yet because
1135      * the host notifier isn't attached.
1136      */
1137     if (s->dataplane_stopping || !s->dataplane_started) {
1138         return;
1139     }
1140
1141     for (uint32_t i = 0; i < total_queues; i++) {
1142         VirtQueue *vq = virtio_get_queue(vdev, i);
1143         virtio_queue_aio_detach_host_notifier(vq, s->ctx);
1144     }
1145 }
1146
1147 /* Resume virtqueue ioeventfd processing after drain */
1148 static void virtio_scsi_drained_end(SCSIBus *bus)
1149 {
1150     VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
1151     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
1152     VirtIODevice *vdev = VIRTIO_DEVICE(s);
1153     uint32_t total_queues = VIRTIO_SCSI_VQ_NUM_FIXED +
1154                             s->parent_obj.conf.num_queues;
1155
1156     /*
1157      * Drain is called when stopping dataplane. Keep the host notifier detached
1158      * so it's not left dangling after dataplane is stopped.
1159      *
1160      * Also, don't attach if dataplane has not even been started yet. We're not
1161      * ready.
1162      */
1163     if (s->dataplane_stopping || !s->dataplane_started) {
1164         return;
1165     }
1166
1167     for (uint32_t i = 0; i < total_queues; i++) {
1168         VirtQueue *vq = virtio_get_queue(vdev, i);
1169         if (vq == vs->event_vq) {
1170             virtio_queue_aio_attach_host_notifier_no_poll(vq, s->ctx);
1171         } else {
1172             virtio_queue_aio_attach_host_notifier(vq, s->ctx);
1173         }
1174     }
1175 }
1176
1177 static struct SCSIBusInfo virtio_scsi_scsi_info = {
1178     .tcq = true,
1179     .max_channel = VIRTIO_SCSI_MAX_CHANNEL,
1180     .max_target = VIRTIO_SCSI_MAX_TARGET,
1181     .max_lun = VIRTIO_SCSI_MAX_LUN,
1182
1183     .complete = virtio_scsi_command_complete,
1184     .fail = virtio_scsi_command_failed,
1185     .cancel = virtio_scsi_request_cancelled,
1186     .change = virtio_scsi_change,
1187     .parse_cdb = virtio_scsi_parse_cdb,
1188     .get_sg_list = virtio_scsi_get_sg_list,
1189     .save_request = virtio_scsi_save_request,
1190     .load_request = virtio_scsi_load_request,
1191     .drained_begin = virtio_scsi_drained_begin,
1192     .drained_end = virtio_scsi_drained_end,
1193 };
1194
1195 void virtio_scsi_common_realize(DeviceState *dev,
1196                                 VirtIOHandleOutput ctrl,
1197                                 VirtIOHandleOutput evt,
1198                                 VirtIOHandleOutput cmd,
1199                                 Error **errp)
1200 {
1201     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1202     VirtIOSCSICommon *s = VIRTIO_SCSI_COMMON(dev);
1203     int i;
1204
1205     virtio_init(vdev, VIRTIO_ID_SCSI, sizeof(VirtIOSCSIConfig));
1206
1207     if (s->conf.num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
1208         s->conf.num_queues = 1;
1209     }
1210     if (s->conf.num_queues == 0 ||
1211             s->conf.num_queues > VIRTIO_QUEUE_MAX - VIRTIO_SCSI_VQ_NUM_FIXED) {
1212         error_setg(errp, "Invalid number of queues (= %" PRIu32 "), "
1213                          "must be a positive integer less than %d.",
1214                    s->conf.num_queues,
1215                    VIRTIO_QUEUE_MAX - VIRTIO_SCSI_VQ_NUM_FIXED);
1216         virtio_cleanup(vdev);
1217         return;
1218     }
1219     if (s->conf.virtqueue_size <= 2) {
1220         error_setg(errp, "invalid virtqueue_size property (= %" PRIu32 "), "
1221                    "must be > 2", s->conf.virtqueue_size);
1222         return;
1223     }
1224     s->cmd_vqs = g_new0(VirtQueue *, s->conf.num_queues);
1225     s->sense_size = VIRTIO_SCSI_SENSE_DEFAULT_SIZE;
1226     s->cdb_size = VIRTIO_SCSI_CDB_DEFAULT_SIZE;
1227
1228     s->ctrl_vq = virtio_add_queue(vdev, s->conf.virtqueue_size, ctrl);
1229     s->event_vq = virtio_add_queue(vdev, s->conf.virtqueue_size, evt);
1230     for (i = 0; i < s->conf.num_queues; i++) {
1231         s->cmd_vqs[i] = virtio_add_queue(vdev, s->conf.virtqueue_size, cmd);
1232     }
1233 }
1234
1235 static void virtio_scsi_device_realize(DeviceState *dev, Error **errp)
1236 {
1237     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1238     VirtIOSCSI *s = VIRTIO_SCSI(dev);
1239     Error *err = NULL;
1240
1241     QTAILQ_INIT(&s->tmf_bh_list);
1242     qemu_mutex_init(&s->tmf_bh_lock);
1243
1244     virtio_scsi_common_realize(dev,
1245                                virtio_scsi_handle_ctrl,
1246                                virtio_scsi_handle_event,
1247                                virtio_scsi_handle_cmd,
1248                                &err);
1249     if (err != NULL) {
1250         error_propagate(errp, err);
1251         return;
1252     }
1253
1254     scsi_bus_init_named(&s->bus, sizeof(s->bus), dev,
1255                        &virtio_scsi_scsi_info, vdev->bus_name);
1256     /* override default SCSI bus hotplug-handler, with virtio-scsi's one */
1257     qbus_set_hotplug_handler(BUS(&s->bus), OBJECT(dev));
1258
1259     virtio_scsi_dataplane_setup(s, errp);
1260 }
1261
1262 void virtio_scsi_common_unrealize(DeviceState *dev)
1263 {
1264     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1265     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(dev);
1266     int i;
1267
1268     virtio_delete_queue(vs->ctrl_vq);
1269     virtio_delete_queue(vs->event_vq);
1270     for (i = 0; i < vs->conf.num_queues; i++) {
1271         virtio_delete_queue(vs->cmd_vqs[i]);
1272     }
1273     g_free(vs->cmd_vqs);
1274     virtio_cleanup(vdev);
1275 }
1276
1277 static void virtio_scsi_device_unrealize(DeviceState *dev)
1278 {
1279     VirtIOSCSI *s = VIRTIO_SCSI(dev);
1280
1281     virtio_scsi_reset_tmf_bh(s);
1282
1283     qbus_set_hotplug_handler(BUS(&s->bus), NULL);
1284     virtio_scsi_common_unrealize(dev);
1285     qemu_mutex_destroy(&s->tmf_bh_lock);
1286 }
1287
1288 static Property virtio_scsi_properties[] = {
1289     DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues,
1290                        VIRTIO_SCSI_AUTO_NUM_QUEUES),
1291     DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSI,
1292                                          parent_obj.conf.virtqueue_size, 256),
1293     DEFINE_PROP_BOOL("seg_max_adjust", VirtIOSCSI,
1294                       parent_obj.conf.seg_max_adjust, true),
1295     DEFINE_PROP_UINT32("max_sectors", VirtIOSCSI, parent_obj.conf.max_sectors,
1296                                                   0xFFFF),
1297     DEFINE_PROP_UINT32("cmd_per_lun", VirtIOSCSI, parent_obj.conf.cmd_per_lun,
1298                                                   128),
1299     DEFINE_PROP_BIT("hotplug", VirtIOSCSI, host_features,
1300                                            VIRTIO_SCSI_F_HOTPLUG, true),
1301     DEFINE_PROP_BIT("param_change", VirtIOSCSI, host_features,
1302                                                 VIRTIO_SCSI_F_CHANGE, true),
1303     DEFINE_PROP_LINK("iothread", VirtIOSCSI, parent_obj.conf.iothread,
1304                      TYPE_IOTHREAD, IOThread *),
1305     DEFINE_PROP_END_OF_LIST(),
1306 };
1307
1308 static const VMStateDescription vmstate_virtio_scsi = {
1309     .name = "virtio-scsi",
1310     .minimum_version_id = 1,
1311     .version_id = 1,
1312     .fields = (const VMStateField[]) {
1313         VMSTATE_VIRTIO_DEVICE,
1314         VMSTATE_END_OF_LIST()
1315     },
1316 };
1317
1318 static void virtio_scsi_common_class_init(ObjectClass *klass, void *data)
1319 {
1320     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
1321     DeviceClass *dc = DEVICE_CLASS(klass);
1322
1323     vdc->get_config = virtio_scsi_get_config;
1324     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
1325 }
1326
1327 static void virtio_scsi_class_init(ObjectClass *klass, void *data)
1328 {
1329     DeviceClass *dc = DEVICE_CLASS(klass);
1330     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
1331     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
1332
1333     device_class_set_props(dc, virtio_scsi_properties);
1334     dc->vmsd = &vmstate_virtio_scsi;
1335     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
1336     vdc->realize = virtio_scsi_device_realize;
1337     vdc->unrealize = virtio_scsi_device_unrealize;
1338     vdc->set_config = virtio_scsi_set_config;
1339     vdc->get_features = virtio_scsi_get_features;
1340     vdc->reset = virtio_scsi_reset;
1341     vdc->start_ioeventfd = virtio_scsi_dataplane_start;
1342     vdc->stop_ioeventfd = virtio_scsi_dataplane_stop;
1343     hc->pre_plug = virtio_scsi_pre_hotplug;
1344     hc->plug = virtio_scsi_hotplug;
1345     hc->unplug = virtio_scsi_hotunplug;
1346 }
1347
1348 static const TypeInfo virtio_scsi_common_info = {
1349     .name = TYPE_VIRTIO_SCSI_COMMON,
1350     .parent = TYPE_VIRTIO_DEVICE,
1351     .instance_size = sizeof(VirtIOSCSICommon),
1352     .abstract = true,
1353     .class_init = virtio_scsi_common_class_init,
1354 };
1355
1356 static const TypeInfo virtio_scsi_info = {
1357     .name = TYPE_VIRTIO_SCSI,
1358     .parent = TYPE_VIRTIO_SCSI_COMMON,
1359     .instance_size = sizeof(VirtIOSCSI),
1360     .class_init = virtio_scsi_class_init,
1361     .interfaces = (InterfaceInfo[]) {
1362         { TYPE_HOTPLUG_HANDLER },
1363         { }
1364     }
1365 };
1366
1367 static void virtio_register_types(void)
1368 {
1369     type_register_static(&virtio_scsi_common_info);
1370     type_register_static(&virtio_scsi_info);
1371 }
1372
1373 type_init(virtio_register_types)