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 "qemu/error-report.h"
  21 #include "qemu/iov.h"
  22 #include "sysemu/block-backend.h"
  23 #include "hw/scsi/scsi.h"
  24 #include "scsi/constants.h"
  25 #include "hw/virtio/virtio-bus.h"
  26 #include "hw/virtio/virtio-access.h"
  27
  28 static inline int virtio_scsi_get_lun(uint8_t *lun)
  29 {
  30     return ((lun[2] << 8) | lun[3]) & 0x3FFF;
  31 }
  32
  33 static inline SCSIDevice *virtio_scsi_device_find(VirtIOSCSI *s, uint8_t *lun)
  34 {
  35     if (lun[0] != 1) {
  36         return NULL;
  37     }
  38     if (lun[2] != 0 && !(lun[2] >= 0x40 && lun[2] < 0x80)) {
  39         return NULL;
  40     }
  41     return scsi_device_find(&s->bus, 0, lun[1], virtio_scsi_get_lun(lun));
  42 }
  43
  44 void virtio_scsi_init_req(VirtIOSCSI *s, VirtQueue *vq, VirtIOSCSIReq *req)
  45 {
  46     VirtIODevice *vdev = VIRTIO_DEVICE(s);
  47     const size_t zero_skip =
  48         offsetof(VirtIOSCSIReq, resp_iov) + sizeof(req->resp_iov);
  49
  50     req->vq = vq;
  51     req->dev = s;
  52     qemu_sglist_init(&req->qsgl, DEVICE(s), 8, vdev->dma_as);
  53     qemu_iovec_init(&req->resp_iov, 1);
  54     memset((uint8_t *)req + zero_skip, 0, sizeof(*req) - zero_skip);
  55 }
  56
  57 void virtio_scsi_free_req(VirtIOSCSIReq *req)
  58 {
  59     qemu_iovec_destroy(&req->resp_iov);
  60     qemu_sglist_destroy(&req->qsgl);
  61     g_free(req);
  62 }
  63
  64 static void virtio_scsi_complete_req(VirtIOSCSIReq *req)
  65 {
  66     VirtIOSCSI *s = req->dev;
  67     VirtQueue *vq = req->vq;
  68     VirtIODevice *vdev = VIRTIO_DEVICE(s);
  69
  70     qemu_iovec_from_buf(&req->resp_iov, 0, &req->resp, req->resp_size);
  71     virtqueue_push(vq, &req->elem, req->qsgl.size + req->resp_iov.size);
  72     if (s->dataplane_started && !s->dataplane_fenced) {
  73         virtio_notify_irqfd(vdev, vq);
  74     } else {
  75         virtio_notify(vdev, vq);
  76     }
  77
  78     if (req->sreq) {
  79         req->sreq->hba_private = NULL;
  80         scsi_req_unref(req->sreq);
  81     }
  82     virtio_scsi_free_req(req);
  83 }
  84
  85 static void virtio_scsi_bad_req(VirtIOSCSIReq *req)
  86 {
  87     virtio_error(VIRTIO_DEVICE(req->dev), "wrong size for virtio-scsi headers");
  88     virtqueue_detach_element(req->vq, &req->elem, 0);
  89     virtio_scsi_free_req(req);
  90 }
  91
  92 static size_t qemu_sgl_concat(VirtIOSCSIReq *req, struct iovec *iov,
  93                               hwaddr *addr, int num, size_t skip)
  94 {
  95     QEMUSGList *qsgl = &req->qsgl;
  96     size_t copied = 0;
  97
  98     while (num) {
  99         if (skip >= iov->iov_len) {
 100             skip -= iov->iov_len;
 101         } else {
 102             qemu_sglist_add(qsgl, *addr + skip, iov->iov_len - skip);
 103             copied += iov->iov_len - skip;
 104             skip = 0;
 105         }
 106         iov++;
 107         addr++;
 108         num--;
 109     }
 110
 111     assert(skip == 0);
 112     return copied;
 113 }
 114
 115 static int virtio_scsi_parse_req(VirtIOSCSIReq *req,
 116                                  unsigned req_size, unsigned resp_size)
 117 {
 118     VirtIODevice *vdev = (VirtIODevice *) req->dev;
 119     size_t in_size, out_size;
 120
 121     if (iov_to_buf(req->elem.out_sg, req->elem.out_num, 0,
 122                    &req->req, req_size) < req_size) {
 123         return -EINVAL;
 124     }
 125
 126     if (qemu_iovec_concat_iov(&req->resp_iov,
 127                               req->elem.in_sg, req->elem.in_num, 0,
 128                               resp_size) < resp_size) {
 129         return -EINVAL;
 130     }
 131
 132     req->resp_size = resp_size;
 133
 134     /* Old BIOSes left some padding by mistake after the req_size/resp_size.
 135      * As a workaround, always consider the first buffer as the virtio-scsi
 136      * request/response, making the payload start at the second element
 137      * of the iovec.
 138      *
 139      * The actual length of the response header, stored in req->resp_size,
 140      * does not change.
 141      *
 142      * TODO: always disable this workaround for virtio 1.0 devices.
 143      */
 144     if (!virtio_vdev_has_feature(vdev, VIRTIO_F_ANY_LAYOUT)) {
 145         if (req->elem.out_num) {
 146             req_size = req->elem.out_sg[0].iov_len;
 147         }
 148         if (req->elem.in_num) {
 149             resp_size = req->elem.in_sg[0].iov_len;
 150         }
 151     }
 152
 153     out_size = qemu_sgl_concat(req, req->elem.out_sg,
 154                                &req->elem.out_addr[0], req->elem.out_num,
 155                                req_size);
 156     in_size = qemu_sgl_concat(req, req->elem.in_sg,
 157                               &req->elem.in_addr[0], req->elem.in_num,
 158                               resp_size);
 159
 160     if (out_size && in_size) {
 161         return -ENOTSUP;
 162     }
 163
 164     if (out_size) {
 165         req->mode = SCSI_XFER_TO_DEV;
 166     } else if (in_size) {
 167         req->mode = SCSI_XFER_FROM_DEV;
 168     }
 169
 170     return 0;
 171 }
 172
 173 static VirtIOSCSIReq *virtio_scsi_pop_req(VirtIOSCSI *s, VirtQueue *vq)
 174 {
 175     VirtIOSCSICommon *vs = (VirtIOSCSICommon *)s;
 176     VirtIOSCSIReq *req;
 177
 178     req = virtqueue_pop(vq, sizeof(VirtIOSCSIReq) + vs->cdb_size);
 179     if (!req) {
 180         return NULL;
 181     }
 182     virtio_scsi_init_req(s, vq, req);
 183     return req;
 184 }
 185
 186 static void virtio_scsi_save_request(QEMUFile *f, SCSIRequest *sreq)
 187 {
 188     VirtIOSCSIReq *req = sreq->hba_private;
 189     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(req->dev);
 190     uint32_t n = virtio_get_queue_index(req->vq) - 2;
 191
 192     assert(n < vs->conf.num_queues);
 193     qemu_put_be32s(f, &n);
 194     qemu_put_virtqueue_element(f, &req->elem);
 195 }
 196
 197 static void *virtio_scsi_load_request(QEMUFile *f, SCSIRequest *sreq)
 198 {
 199     SCSIBus *bus = sreq->bus;
 200     VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
 201     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
 202     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 203     VirtIOSCSIReq *req;
 204     uint32_t n;
 205
 206     qemu_get_be32s(f, &n);
 207     assert(n < vs->conf.num_queues);
 208     req = qemu_get_virtqueue_element(vdev, f,
 209                                      sizeof(VirtIOSCSIReq) + vs->cdb_size);
 210     virtio_scsi_init_req(s, vs->cmd_vqs[n], req);
 211
 212     if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICmdReq) + vs->cdb_size,
 213                               sizeof(VirtIOSCSICmdResp) + vs->sense_size) < 0) {
 214         error_report("invalid SCSI request migration data");
 215         exit(1);
 216     }
 217
 218     scsi_req_ref(sreq);
 219     req->sreq = sreq;
 220     if (req->sreq->cmd.mode != SCSI_XFER_NONE) {
 221         assert(req->sreq->cmd.mode == req->mode);
 222     }
 223     return req;
 224 }
 225
 226 typedef struct {
 227     Notifier        notifier;
 228     VirtIOSCSIReq  *tmf_req;
 229 } VirtIOSCSICancelNotifier;
 230
 231 static void virtio_scsi_cancel_notify(Notifier *notifier, void *data)
 232 {
 233     VirtIOSCSICancelNotifier *n = container_of(notifier,
 234                                                VirtIOSCSICancelNotifier,
 235                                                notifier);
 236
 237     if (--n->tmf_req->remaining == 0) {
 238         virtio_scsi_complete_req(n->tmf_req);
 239     }
 240     g_free(n);
 241 }
 242
 243 static inline void virtio_scsi_ctx_check(VirtIOSCSI *s, SCSIDevice *d)
 244 {
 245     if (s->dataplane_started && d && blk_is_available(d->conf.blk)) {
 246         assert(blk_get_aio_context(d->conf.blk) == s->ctx);
 247     }
 248 }
 249
 250 /* Return 0 if the request is ready to be completed and return to guest;
 251  * -EINPROGRESS if the request is submitted and will be completed later, in the
 252  *  case of async cancellation. */
 253 static int virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req)
 254 {
 255     SCSIDevice *d = virtio_scsi_device_find(s, req->req.tmf.lun);
 256     SCSIRequest *r, *next;
 257     BusChild *kid;
 258     int target;
 259     int ret = 0;
 260
 261     virtio_scsi_ctx_check(s, d);
 262     /* Here VIRTIO_SCSI_S_OK means "FUNCTION COMPLETE".  */
 263     req->resp.tmf.response = VIRTIO_SCSI_S_OK;
 264
 265     virtio_tswap32s(VIRTIO_DEVICE(s), &req->req.tmf.subtype);
 266     switch (req->req.tmf.subtype) {
 267     case VIRTIO_SCSI_T_TMF_ABORT_TASK:
 268     case VIRTIO_SCSI_T_TMF_QUERY_TASK:
 269         if (!d) {
 270             goto fail;
 271         }
 272         if (d->lun != virtio_scsi_get_lun(req->req.tmf.lun)) {
 273             goto incorrect_lun;
 274         }
 275         QTAILQ_FOREACH_SAFE(r, &d->requests, next, next) {
 276             VirtIOSCSIReq *cmd_req = r->hba_private;
 277             if (cmd_req && cmd_req->req.cmd.tag == req->req.tmf.tag) {
 278                 break;
 279             }
 280         }
 281         if (r) {
 282             /*
 283              * Assert that the request has not been completed yet, we
 284              * check for it in the loop above.
 285              */
 286             assert(r->hba_private);
 287             if (req->req.tmf.subtype == VIRTIO_SCSI_T_TMF_QUERY_TASK) {
 288                 /* "If the specified command is present in the task set, then
 289                  * return a service response set to FUNCTION SUCCEEDED".
 290                  */
 291                 req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
 292             } else {
 293                 VirtIOSCSICancelNotifier *notifier;
 294
 295                 req->remaining = 1;
 296                 notifier = g_new(VirtIOSCSICancelNotifier, 1);
 297                 notifier->tmf_req = req;
 298                 notifier->notifier.notify = virtio_scsi_cancel_notify;
 299                 scsi_req_cancel_async(r, &notifier->notifier);
 300                 ret = -EINPROGRESS;
 301             }
 302         }
 303         break;
 304
 305     case VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET:
 306         if (!d) {
 307             goto fail;
 308         }
 309         if (d->lun != virtio_scsi_get_lun(req->req.tmf.lun)) {
 310             goto incorrect_lun;
 311         }
 312         s->resetting++;
 313         qdev_reset_all(&d->qdev);
 314         s->resetting--;
 315         break;
 316
 317     case VIRTIO_SCSI_T_TMF_ABORT_TASK_SET:
 318     case VIRTIO_SCSI_T_TMF_CLEAR_TASK_SET:
 319     case VIRTIO_SCSI_T_TMF_QUERY_TASK_SET:
 320         if (!d) {
 321             goto fail;
 322         }
 323         if (d->lun != virtio_scsi_get_lun(req->req.tmf.lun)) {
 324             goto incorrect_lun;
 325         }
 326
 327         /* Add 1 to "remaining" until virtio_scsi_do_tmf returns.
 328          * This way, if the bus starts calling back to the notifiers
 329          * even before we finish the loop, virtio_scsi_cancel_notify
 330          * will not complete the TMF too early.
 331          */
 332         req->remaining = 1;
 333         QTAILQ_FOREACH_SAFE(r, &d->requests, next, next) {
 334             if (r->hba_private) {
 335                 if (req->req.tmf.subtype == VIRTIO_SCSI_T_TMF_QUERY_TASK_SET) {
 336                     /* "If there is any command present in the task set, then
 337                      * return a service response set to FUNCTION SUCCEEDED".
 338                      */
 339                     req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
 340                     break;
 341                 } else {
 342                     VirtIOSCSICancelNotifier *notifier;
 343
 344                     req->remaining++;
 345                     notifier = g_new(VirtIOSCSICancelNotifier, 1);
 346                     notifier->notifier.notify = virtio_scsi_cancel_notify;
 347                     notifier->tmf_req = req;
 348                     scsi_req_cancel_async(r, &notifier->notifier);
 349                 }
 350             }
 351         }
 352         if (--req->remaining > 0) {
 353             ret = -EINPROGRESS;
 354         }
 355         break;
 356
 357     case VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET:
 358         target = req->req.tmf.lun[1];
 359         s->resetting++;
 360         QTAILQ_FOREACH(kid, &s->bus.qbus.children, sibling) {
 361              d = SCSI_DEVICE(kid->child);
 362              if (d->channel == 0 && d->id == target) {
 363                 qdev_reset_all(&d->qdev);
 364              }
 365         }
 366         s->resetting--;
 367         break;
 368
 369     case VIRTIO_SCSI_T_TMF_CLEAR_ACA:
 370     default:
 371         req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_REJECTED;
 372         break;
 373     }
 374
 375     return ret;
 376
 377 incorrect_lun:
 378     req->resp.tmf.response = VIRTIO_SCSI_S_INCORRECT_LUN;
 379     return ret;
 380
 381 fail:
 382     req->resp.tmf.response = VIRTIO_SCSI_S_BAD_TARGET;
 383     return ret;
 384 }
 385
 386 static void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s, VirtIOSCSIReq *req)
 387 {
 388     VirtIODevice *vdev = (VirtIODevice *)s;
 389     uint32_t type;
 390     int r = 0;
 391
 392     if (iov_to_buf(req->elem.out_sg, req->elem.out_num, 0,
 393                 &type, sizeof(type)) < sizeof(type)) {
 394         virtio_scsi_bad_req(req);
 395         return;
 396     }
 397
 398     virtio_tswap32s(vdev, &type);
 399     if (type == VIRTIO_SCSI_T_TMF) {
 400         if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICtrlTMFReq),
 401                     sizeof(VirtIOSCSICtrlTMFResp)) < 0) {
 402             virtio_scsi_bad_req(req);
 403             return;
 404         } else {
 405             r = virtio_scsi_do_tmf(s, req);
 406         }
 407
 408     } else if (type == VIRTIO_SCSI_T_AN_QUERY ||
 409                type == VIRTIO_SCSI_T_AN_SUBSCRIBE) {
 410         if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICtrlANReq),
 411                     sizeof(VirtIOSCSICtrlANResp)) < 0) {
 412             virtio_scsi_bad_req(req);
 413             return;
 414         } else {
 415             req->resp.an.event_actual = 0;
 416             req->resp.an.response = VIRTIO_SCSI_S_OK;
 417         }
 418     }
 419     if (r == 0) {
 420         virtio_scsi_complete_req(req);
 421     } else {
 422         assert(r == -EINPROGRESS);
 423     }
 424 }
 425
 426 bool virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq)
 427 {
 428     VirtIOSCSIReq *req;
 429     bool progress = false;
 430
 431     while ((req = virtio_scsi_pop_req(s, vq))) {
 432         progress = true;
 433         virtio_scsi_handle_ctrl_req(s, req);
 434     }
 435     return progress;
 436 }
 437
 438 static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
 439 {
 440     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
 441
 442     if (s->ctx) {
 443         virtio_device_start_ioeventfd(vdev);
 444         if (!s->dataplane_fenced) {
 445             return;
 446         }
 447     }
 448     virtio_scsi_acquire(s);
 449     virtio_scsi_handle_ctrl_vq(s, vq);
 450     virtio_scsi_release(s);
 451 }
 452
 453 static void virtio_scsi_complete_cmd_req(VirtIOSCSIReq *req)
 454 {
 455     /* Sense data is not in req->resp and is copied separately
 456      * in virtio_scsi_command_complete.
 457      */
 458     req->resp_size = sizeof(VirtIOSCSICmdResp);
 459     virtio_scsi_complete_req(req);
 460 }
 461
 462 static void virtio_scsi_command_complete(SCSIRequest *r, uint32_t status,
 463                                          size_t resid)
 464 {
 465     VirtIOSCSIReq *req = r->hba_private;
 466     uint8_t sense[SCSI_SENSE_BUF_SIZE];
 467     uint32_t sense_len;
 468     VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
 469
 470     if (r->io_canceled) {
 471         return;
 472     }
 473
 474     req->resp.cmd.response = VIRTIO_SCSI_S_OK;
 475     req->resp.cmd.status = status;
 476     if (req->resp.cmd.status == GOOD) {
 477         req->resp.cmd.resid = virtio_tswap32(vdev, resid);
 478     } else {
 479         req->resp.cmd.resid = 0;
 480         sense_len = scsi_req_get_sense(r, sense, sizeof(sense));
 481         sense_len = MIN(sense_len, req->resp_iov.size - sizeof(req->resp.cmd));
 482         qemu_iovec_from_buf(&req->resp_iov, sizeof(req->resp.cmd),
 483                             sense, sense_len);
 484         req->resp.cmd.sense_len = virtio_tswap32(vdev, sense_len);
 485     }
 486     virtio_scsi_complete_cmd_req(req);
 487 }
 488
 489 static int virtio_scsi_parse_cdb(SCSIDevice *dev, SCSICommand *cmd,
 490                                  uint8_t *buf, void *hba_private)
 491 {
 492     VirtIOSCSIReq *req = hba_private;
 493
 494     if (cmd->len == 0) {
 495         cmd->len = MIN(VIRTIO_SCSI_CDB_DEFAULT_SIZE, SCSI_CMD_BUF_SIZE);
 496         memcpy(cmd->buf, buf, cmd->len);
 497     }
 498
 499     /* Extract the direction and mode directly from the request, for
 500      * host device passthrough.
 501      */
 502     cmd->xfer = req->qsgl.size;
 503     cmd->mode = req->mode;
 504     return 0;
 505 }
 506
 507 static QEMUSGList *virtio_scsi_get_sg_list(SCSIRequest *r)
 508 {
 509     VirtIOSCSIReq *req = r->hba_private;
 510
 511     return &req->qsgl;
 512 }
 513
 514 static void virtio_scsi_request_cancelled(SCSIRequest *r)
 515 {
 516     VirtIOSCSIReq *req = r->hba_private;
 517
 518     if (!req) {
 519         return;
 520     }
 521     if (req->dev->resetting) {
 522         req->resp.cmd.response = VIRTIO_SCSI_S_RESET;
 523     } else {
 524         req->resp.cmd.response = VIRTIO_SCSI_S_ABORTED;
 525     }
 526     virtio_scsi_complete_cmd_req(req);
 527 }
 528
 529 static void virtio_scsi_fail_cmd_req(VirtIOSCSIReq *req)
 530 {
 531     req->resp.cmd.response = VIRTIO_SCSI_S_FAILURE;
 532     virtio_scsi_complete_cmd_req(req);
 533 }
 534
 535 static int virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, VirtIOSCSIReq *req)
 536 {
 537     VirtIOSCSICommon *vs = &s->parent_obj;
 538     SCSIDevice *d;
 539     int rc;
 540
 541     rc = virtio_scsi_parse_req(req, sizeof(VirtIOSCSICmdReq) + vs->cdb_size,
 542                                sizeof(VirtIOSCSICmdResp) + vs->sense_size);
 543     if (rc < 0) {
 544         if (rc == -ENOTSUP) {
 545             virtio_scsi_fail_cmd_req(req);
 546             return -ENOTSUP;
 547         } else {
 548             virtio_scsi_bad_req(req);
 549             return -EINVAL;
 550         }
 551     }
 552
 553     d = virtio_scsi_device_find(s, req->req.cmd.lun);
 554     if (!d) {
 555         req->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
 556         virtio_scsi_complete_cmd_req(req);
 557         return -ENOENT;
 558     }
 559     virtio_scsi_ctx_check(s, d);
 560     req->sreq = scsi_req_new(d, req->req.cmd.tag,
 561                              virtio_scsi_get_lun(req->req.cmd.lun),
 562                              req->req.cmd.cdb, req);
 563
 564     if (req->sreq->cmd.mode != SCSI_XFER_NONE
 565         && (req->sreq->cmd.mode != req->mode ||
 566             req->sreq->cmd.xfer > req->qsgl.size)) {
 567         req->resp.cmd.response = VIRTIO_SCSI_S_OVERRUN;
 568         virtio_scsi_complete_cmd_req(req);
 569         return -ENOBUFS;
 570     }
 571     scsi_req_ref(req->sreq);
 572     blk_io_plug(d->conf.blk);
 573     return 0;
 574 }
 575
 576 static void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI *s, VirtIOSCSIReq *req)
 577 {
 578     SCSIRequest *sreq = req->sreq;
 579     if (scsi_req_enqueue(sreq)) {
 580         scsi_req_continue(sreq);
 581     }
 582     blk_io_unplug(sreq->dev->conf.blk);
 583     scsi_req_unref(sreq);
 584 }
 585
 586 bool virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
 587 {
 588     VirtIOSCSIReq *req, *next;
 589     int ret = 0;
 590     bool progress = false;
 591
 592     QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs);
 593
 594     do {
 595         virtio_queue_set_notification(vq, 0);
 596
 597         while ((req = virtio_scsi_pop_req(s, vq))) {
 598             progress = true;
 599             ret = virtio_scsi_handle_cmd_req_prepare(s, req);
 600             if (!ret) {
 601                 QTAILQ_INSERT_TAIL(&reqs, req, next);
 602             } else if (ret == -EINVAL) {
 603                 /* The device is broken and shouldn't process any request */
 604                 while (!QTAILQ_EMPTY(&reqs)) {
 605                     req = QTAILQ_FIRST(&reqs);
 606                     QTAILQ_REMOVE(&reqs, req, next);
 607                     blk_io_unplug(req->sreq->dev->conf.blk);
 608                     scsi_req_unref(req->sreq);
 609                     virtqueue_detach_element(req->vq, &req->elem, 0);
 610                     virtio_scsi_free_req(req);
 611                 }
 612             }
 613         }
 614
 615         virtio_queue_set_notification(vq, 1);
 616     } while (ret != -EINVAL && !virtio_queue_empty(vq));
 617
 618     QTAILQ_FOREACH_SAFE(req, &reqs, next, next) {
 619         virtio_scsi_handle_cmd_req_submit(s, req);
 620     }
 621     return progress;
 622 }
 623
 624 static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)
 625 {
 626     /* use non-QOM casts in the data path */
 627     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
 628
 629     if (s->ctx) {
 630         virtio_device_start_ioeventfd(vdev);
 631         if (!s->dataplane_fenced) {
 632             return;
 633         }
 634     }
 635     virtio_scsi_acquire(s);
 636     virtio_scsi_handle_cmd_vq(s, vq);
 637     virtio_scsi_release(s);
 638 }
 639
 640 static void virtio_scsi_get_config(VirtIODevice *vdev,
 641                                    uint8_t *config)
 642 {
 643     VirtIOSCSIConfig *scsiconf = (VirtIOSCSIConfig *)config;
 644     VirtIOSCSICommon *s = VIRTIO_SCSI_COMMON(vdev);
 645
 646     virtio_stl_p(vdev, &scsiconf->num_queues, s->conf.num_queues);
 647     virtio_stl_p(vdev, &scsiconf->seg_max, 128 - 2);
 648     virtio_stl_p(vdev, &scsiconf->max_sectors, s->conf.max_sectors);
 649     virtio_stl_p(vdev, &scsiconf->cmd_per_lun, s->conf.cmd_per_lun);
 650     virtio_stl_p(vdev, &scsiconf->event_info_size, sizeof(VirtIOSCSIEvent));
 651     virtio_stl_p(vdev, &scsiconf->sense_size, s->sense_size);
 652     virtio_stl_p(vdev, &scsiconf->cdb_size, s->cdb_size);
 653     virtio_stw_p(vdev, &scsiconf->max_channel, VIRTIO_SCSI_MAX_CHANNEL);
 654     virtio_stw_p(vdev, &scsiconf->max_target, VIRTIO_SCSI_MAX_TARGET);
 655     virtio_stl_p(vdev, &scsiconf->max_lun, VIRTIO_SCSI_MAX_LUN);
 656 }
 657
 658 static void virtio_scsi_set_config(VirtIODevice *vdev,
 659                                    const uint8_t *config)
 660 {
 661     VirtIOSCSIConfig *scsiconf = (VirtIOSCSIConfig *)config;
 662     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
 663
 664     if ((uint32_t) virtio_ldl_p(vdev, &scsiconf->sense_size) >= 65536 ||
 665         (uint32_t) virtio_ldl_p(vdev, &scsiconf->cdb_size) >= 256) {
 666         virtio_error(vdev,
 667                      "bad data written to virtio-scsi configuration space");
 668         return;
 669     }
 670
 671     vs->sense_size = virtio_ldl_p(vdev, &scsiconf->sense_size);
 672     vs->cdb_size = virtio_ldl_p(vdev, &scsiconf->cdb_size);
 673 }
 674
 675 static uint64_t virtio_scsi_get_features(VirtIODevice *vdev,
 676                                          uint64_t requested_features,
 677                                          Error **errp)
 678 {
 679     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
 680
 681     /* Firstly sync all virtio-scsi possible supported features */
 682     requested_features |= s->host_features;
 683     return requested_features;
 684 }
 685
 686 static void virtio_scsi_reset(VirtIODevice *vdev)
 687 {
 688     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
 689     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
 690
 691     assert(!s->dataplane_started);
 692     s->resetting++;
 693     qbus_reset_all(&s->bus.qbus);
 694     s->resetting--;
 695
 696     vs->sense_size = VIRTIO_SCSI_SENSE_DEFAULT_SIZE;
 697     vs->cdb_size = VIRTIO_SCSI_CDB_DEFAULT_SIZE;
 698     s->events_dropped = false;
 699 }
 700
 701 void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev,
 702                             uint32_t event, uint32_t reason)
 703 {
 704     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
 705     VirtIOSCSIReq *req;
 706     VirtIOSCSIEvent *evt;
 707     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 708
 709     if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 710         return;
 711     }
 712
 713     req = virtio_scsi_pop_req(s, vs->event_vq);
 714     if (!req) {
 715         s->events_dropped = true;
 716         return;
 717     }
 718
 719     if (s->events_dropped) {
 720         event |= VIRTIO_SCSI_T_EVENTS_MISSED;
 721         s->events_dropped = false;
 722     }
 723
 724     if (virtio_scsi_parse_req(req, 0, sizeof(VirtIOSCSIEvent))) {
 725         virtio_scsi_bad_req(req);
 726         return;
 727     }
 728
 729     evt = &req->resp.event;
 730     memset(evt, 0, sizeof(VirtIOSCSIEvent));
 731     evt->event = virtio_tswap32(vdev, event);
 732     evt->reason = virtio_tswap32(vdev, reason);
 733     if (!dev) {
 734         assert(event == VIRTIO_SCSI_T_EVENTS_MISSED);
 735     } else {
 736         evt->lun[0] = 1;
 737         evt->lun[1] = dev->id;
 738
 739         /* Linux wants us to keep the same encoding we use for REPORT LUNS.  */
 740         if (dev->lun >= 256) {
 741             evt->lun[2] = (dev->lun >> 8) | 0x40;
 742         }
 743         evt->lun[3] = dev->lun & 0xFF;
 744     }
 745     virtio_scsi_complete_req(req);
 746 }
 747
 748 bool virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq)
 749 {
 750     if (s->events_dropped) {
 751         virtio_scsi_push_event(s, NULL, VIRTIO_SCSI_T_NO_EVENT, 0);
 752         return true;
 753     }
 754     return false;
 755 }
 756
 757 static void virtio_scsi_handle_event(VirtIODevice *vdev, VirtQueue *vq)
 758 {
 759     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
 760
 761     if (s->ctx) {
 762         virtio_device_start_ioeventfd(vdev);
 763         if (!s->dataplane_fenced) {
 764             return;
 765         }
 766     }
 767     virtio_scsi_acquire(s);
 768     virtio_scsi_handle_event_vq(s, vq);
 769     virtio_scsi_release(s);
 770 }
 771
 772 static void virtio_scsi_change(SCSIBus *bus, SCSIDevice *dev, SCSISense sense)
 773 {
 774     VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
 775     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 776
 777     if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_CHANGE) &&
 778         dev->type != TYPE_ROM) {
 779         virtio_scsi_acquire(s);
 780         virtio_scsi_push_event(s, dev, VIRTIO_SCSI_T_PARAM_CHANGE,
 781                                sense.asc | (sense.ascq << 8));
 782         virtio_scsi_release(s);
 783     }
 784 }
 785
 786 static void virtio_scsi_hotplug(HotplugHandler *hotplug_dev, DeviceState *dev,
 787                                 Error **errp)
 788 {
 789     VirtIODevice *vdev = VIRTIO_DEVICE(hotplug_dev);
 790     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
 791     SCSIDevice *sd = SCSI_DEVICE(dev);
 792
 793     if (s->ctx && !s->dataplane_fenced) {
 794         if (blk_op_is_blocked(sd->conf.blk, BLOCK_OP_TYPE_DATAPLANE, errp)) {
 795             return;
 796         }
 797         virtio_scsi_acquire(s);
 798         blk_set_aio_context(sd->conf.blk, s->ctx);
 799         virtio_scsi_release(s);
 800
 801     }
 802
 803     if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) {
 804         virtio_scsi_acquire(s);
 805         virtio_scsi_push_event(s, sd,
 806                                VIRTIO_SCSI_T_TRANSPORT_RESET,
 807                                VIRTIO_SCSI_EVT_RESET_RESCAN);
 808         virtio_scsi_release(s);
 809     }
 810 }
 811
 812 static void virtio_scsi_hotunplug(HotplugHandler *hotplug_dev, DeviceState *dev,
 813                                   Error **errp)
 814 {
 815     VirtIODevice *vdev = VIRTIO_DEVICE(hotplug_dev);
 816     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
 817     SCSIDevice *sd = SCSI_DEVICE(dev);
 818
 819     if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) {
 820         virtio_scsi_acquire(s);
 821         virtio_scsi_push_event(s, sd,
 822                                VIRTIO_SCSI_T_TRANSPORT_RESET,
 823                                VIRTIO_SCSI_EVT_RESET_REMOVED);
 824         virtio_scsi_release(s);
 825     }
 826
 827     qdev_simple_device_unplug_cb(hotplug_dev, dev, errp);
 828 }
 829
 830 static struct SCSIBusInfo virtio_scsi_scsi_info = {
 831     .tcq = true,
 832     .max_channel = VIRTIO_SCSI_MAX_CHANNEL,
 833     .max_target = VIRTIO_SCSI_MAX_TARGET,
 834     .max_lun = VIRTIO_SCSI_MAX_LUN,
 835
 836     .complete = virtio_scsi_command_complete,
 837     .cancel = virtio_scsi_request_cancelled,
 838     .change = virtio_scsi_change,
 839     .parse_cdb = virtio_scsi_parse_cdb,
 840     .get_sg_list = virtio_scsi_get_sg_list,
 841     .save_request = virtio_scsi_save_request,
 842     .load_request = virtio_scsi_load_request,
 843 };
 844
 845 void virtio_scsi_common_realize(DeviceState *dev,
 846                                 VirtIOHandleOutput ctrl,
 847                                 VirtIOHandleOutput evt,
 848                                 VirtIOHandleOutput cmd,
 849                                 Error **errp)
 850 {
 851     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 852     VirtIOSCSICommon *s = VIRTIO_SCSI_COMMON(dev);
 853     int i;
 854
 855     virtio_init(vdev, "virtio-scsi", VIRTIO_ID_SCSI,
 856                 sizeof(VirtIOSCSIConfig));
 857
 858     if (s->conf.num_queues == 0 ||
 859             s->conf.num_queues > VIRTIO_QUEUE_MAX - 2) {
 860         error_setg(errp, "Invalid number of queues (= %" PRIu32 "), "
 861                          "must be a positive integer less than %d.",
 862                    s->conf.num_queues, VIRTIO_QUEUE_MAX - 2);
 863         virtio_cleanup(vdev);
 864         return;
 865     }
 866     s->cmd_vqs = g_new0(VirtQueue *, s->conf.num_queues);
 867     s->sense_size = VIRTIO_SCSI_SENSE_DEFAULT_SIZE;
 868     s->cdb_size = VIRTIO_SCSI_CDB_DEFAULT_SIZE;
 869
 870     s->ctrl_vq = virtio_add_queue(vdev, s->conf.virtqueue_size, ctrl);
 871     s->event_vq = virtio_add_queue(vdev, s->conf.virtqueue_size, evt);
 872     for (i = 0; i < s->conf.num_queues; i++) {
 873         s->cmd_vqs[i] = virtio_add_queue(vdev, s->conf.virtqueue_size, cmd);
 874     }
 875 }
 876
 877 static void virtio_scsi_device_realize(DeviceState *dev, Error **errp)
 878 {
 879     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 880     VirtIOSCSI *s = VIRTIO_SCSI(dev);
 881     Error *err = NULL;
 882
 883     virtio_scsi_common_realize(dev,
 884                                virtio_scsi_handle_ctrl,
 885                                virtio_scsi_handle_event,
 886                                virtio_scsi_handle_cmd,
 887                                &err);
 888     if (err != NULL) {
 889         error_propagate(errp, err);
 890         return;
 891     }
 892
 893     scsi_bus_new(&s->bus, sizeof(s->bus), dev,
 894                  &virtio_scsi_scsi_info, vdev->bus_name);
 895     /* override default SCSI bus hotplug-handler, with virtio-scsi's one */
 896     qbus_set_hotplug_handler(BUS(&s->bus), dev, &error_abort);
 897
 898     virtio_scsi_dataplane_setup(s, errp);
 899 }
 900
 901 void virtio_scsi_common_unrealize(DeviceState *dev, Error **errp)
 902 {
 903     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 904     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(dev);
 905
 906     g_free(vs->cmd_vqs);
 907     virtio_cleanup(vdev);
 908 }
 909
 910 static void virtio_scsi_device_unrealize(DeviceState *dev, Error **errp)
 911 {
 912     VirtIOSCSI *s = VIRTIO_SCSI(dev);
 913
 914     qbus_set_hotplug_handler(BUS(&s->bus), NULL, &error_abort);
 915     virtio_scsi_common_unrealize(dev, errp);
 916 }
 917
 918 static Property virtio_scsi_properties[] = {
 919     DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues, 1),
 920     DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSI,
 921                                          parent_obj.conf.virtqueue_size, 128),
 922     DEFINE_PROP_UINT32("max_sectors", VirtIOSCSI, parent_obj.conf.max_sectors,
 923                                                   0xFFFF),
 924     DEFINE_PROP_UINT32("cmd_per_lun", VirtIOSCSI, parent_obj.conf.cmd_per_lun,
 925                                                   128),
 926     DEFINE_PROP_BIT("hotplug", VirtIOSCSI, host_features,
 927                                            VIRTIO_SCSI_F_HOTPLUG, true),
 928     DEFINE_PROP_BIT("param_change", VirtIOSCSI, host_features,
 929                                                 VIRTIO_SCSI_F_CHANGE, true),
 930     DEFINE_PROP_LINK("iothread", VirtIOSCSI, parent_obj.conf.iothread,
 931                      TYPE_IOTHREAD, IOThread *),
 932     DEFINE_PROP_END_OF_LIST(),
 933 };
 934
 935 static const VMStateDescription vmstate_virtio_scsi = {
 936     .name = "virtio-scsi",
 937     .minimum_version_id = 1,
 938     .version_id = 1,
 939     .fields = (VMStateField[]) {
 940         VMSTATE_VIRTIO_DEVICE,
 941         VMSTATE_END_OF_LIST()
 942     },
 943 };
 944
 945 static void virtio_scsi_common_class_init(ObjectClass *klass, void *data)
 946 {
 947     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 948     DeviceClass *dc = DEVICE_CLASS(klass);
 949
 950     vdc->get_config = virtio_scsi_get_config;
 951     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 952 }
 953
 954 static void virtio_scsi_class_init(ObjectClass *klass, void *data)
 955 {
 956     DeviceClass *dc = DEVICE_CLASS(klass);
 957     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 958     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
 959
 960     dc->props = virtio_scsi_properties;
 961     dc->vmsd = &vmstate_virtio_scsi;
 962     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 963     vdc->realize = virtio_scsi_device_realize;
 964     vdc->unrealize = virtio_scsi_device_unrealize;
 965     vdc->set_config = virtio_scsi_set_config;
 966     vdc->get_features = virtio_scsi_get_features;
 967     vdc->reset = virtio_scsi_reset;
 968     vdc->start_ioeventfd = virtio_scsi_dataplane_start;
 969     vdc->stop_ioeventfd = virtio_scsi_dataplane_stop;
 970     hc->plug = virtio_scsi_hotplug;
 971     hc->unplug = virtio_scsi_hotunplug;
 972 }
 973
 974 static const TypeInfo virtio_scsi_common_info = {
 975     .name = TYPE_VIRTIO_SCSI_COMMON,
 976     .parent = TYPE_VIRTIO_DEVICE,
 977     .instance_size = sizeof(VirtIOSCSICommon),
 978     .abstract = true,
 979     .class_init = virtio_scsi_common_class_init,
 980 };
 981
 982 static const TypeInfo virtio_scsi_info = {
 983     .name = TYPE_VIRTIO_SCSI,
 984     .parent = TYPE_VIRTIO_SCSI_COMMON,
 985     .instance_size = sizeof(VirtIOSCSI),
 986     .class_init = virtio_scsi_class_init,
 987     .interfaces = (InterfaceInfo[]) {
 988         { TYPE_HOTPLUG_HANDLER },
 989         { }
 990     }
 991 };
 992
 993 static void virtio_register_types(void)
 994 {
 995     type_register_static(&virtio_scsi_common_info);
 996     type_register_static(&virtio_scsi_info);
 997 }
 998
 999 type_init(virtio_register_types)