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/error-report.h"
  22 #include "qemu/iov.h"
  23 #include "qemu/module.h"
  24 #include "sysemu/block-backend.h"
  25 #include "hw/qdev-properties.h"
  26 #include "hw/scsi/scsi.h"
  27 #include "scsi/constants.h"
  28 #include "hw/virtio/virtio-bus.h"
  29 #include "hw/virtio/virtio-access.h"
  30
  31 static inline int virtio_scsi_get_lun(uint8_t *lun)
  32 {
  33     return ((lun[2] << 8) | lun[3]) & 0x3FFF;
  34 }
  35
  36 static inline SCSIDevice *virtio_scsi_device_find(VirtIOSCSI *s, uint8_t *lun)
  37 {
  38     if (lun[0] != 1) {
  39         return NULL;
  40     }
  41     if (lun[2] != 0 && !(lun[2] >= 0x40 && lun[2] < 0x80)) {
  42         return NULL;
  43     }
  44     return scsi_device_find(&s->bus, 0, lun[1], virtio_scsi_get_lun(lun));
  45 }
  46
  47 void virtio_scsi_init_req(VirtIOSCSI *s, VirtQueue *vq, VirtIOSCSIReq *req)
  48 {
  49     VirtIODevice *vdev = VIRTIO_DEVICE(s);
  50     const size_t zero_skip =
  51         offsetof(VirtIOSCSIReq, resp_iov) + sizeof(req->resp_iov);
  52
  53     req->vq = vq;
  54     req->dev = s;
  55     qemu_sglist_init(&req->qsgl, DEVICE(s), 8, vdev->dma_as);
  56     qemu_iovec_init(&req->resp_iov, 1);
  57     memset((uint8_t *)req + zero_skip, 0, sizeof(*req) - zero_skip);
  58 }
  59
  60 void virtio_scsi_free_req(VirtIOSCSIReq *req)
  61 {
  62     qemu_iovec_destroy(&req->resp_iov);
  63     qemu_sglist_destroy(&req->qsgl);
  64     g_free(req);
  65 }
  66
  67 static void virtio_scsi_complete_req(VirtIOSCSIReq *req)
  68 {
  69     VirtIOSCSI *s = req->dev;
  70     VirtQueue *vq = req->vq;
  71     VirtIODevice *vdev = VIRTIO_DEVICE(s);
  72
  73     qemu_iovec_from_buf(&req->resp_iov, 0, &req->resp, req->resp_size);
  74     virtqueue_push(vq, &req->elem, req->qsgl.size + req->resp_iov.size);
  75     if (s->dataplane_started && !s->dataplane_fenced) {
  76         virtio_notify_irqfd(vdev, vq);
  77     } else {
  78         virtio_notify(vdev, vq);
  79     }
  80
  81     if (req->sreq) {
  82         req->sreq->hba_private = NULL;
  83         scsi_req_unref(req->sreq);
  84     }
  85     virtio_scsi_free_req(req);
  86 }
  87
  88 static void virtio_scsi_bad_req(VirtIOSCSIReq *req)
  89 {
  90     virtio_error(VIRTIO_DEVICE(req->dev), "wrong size for virtio-scsi headers");
  91     virtqueue_detach_element(req->vq, &req->elem, 0);
  92     virtio_scsi_free_req(req);
  93 }
  94
  95 static size_t qemu_sgl_concat(VirtIOSCSIReq *req, struct iovec *iov,
  96                               hwaddr *addr, int num, size_t skip)
  97 {
  98     QEMUSGList *qsgl = &req->qsgl;
  99     size_t copied = 0;
 100
 101     while (num) {
 102         if (skip >= iov->iov_len) {
 103             skip -= iov->iov_len;
 104         } else {
 105             qemu_sglist_add(qsgl, *addr + skip, iov->iov_len - skip);
 106             copied += iov->iov_len - skip;
 107             skip = 0;
 108         }
 109         iov++;
 110         addr++;
 111         num--;
 112     }
 113
 114     assert(skip == 0);
 115     return copied;
 116 }
 117
 118 static int virtio_scsi_parse_req(VirtIOSCSIReq *req,
 119                                  unsigned req_size, unsigned resp_size)
 120 {
 121     VirtIODevice *vdev = (VirtIODevice *) req->dev;
 122     size_t in_size, out_size;
 123
 124     if (iov_to_buf(req->elem.out_sg, req->elem.out_num, 0,
 125                    &req->req, req_size) < req_size) {
 126         return -EINVAL;
 127     }
 128
 129     if (qemu_iovec_concat_iov(&req->resp_iov,
 130                               req->elem.in_sg, req->elem.in_num, 0,
 131                               resp_size) < resp_size) {
 132         return -EINVAL;
 133     }
 134
 135     req->resp_size = resp_size;
 136
 137     /* Old BIOSes left some padding by mistake after the req_size/resp_size.
 138      * As a workaround, always consider the first buffer as the virtio-scsi
 139      * request/response, making the payload start at the second element
 140      * of the iovec.
 141      *
 142      * The actual length of the response header, stored in req->resp_size,
 143      * does not change.
 144      *
 145      * TODO: always disable this workaround for virtio 1.0 devices.
 146      */
 147     if (!virtio_vdev_has_feature(vdev, VIRTIO_F_ANY_LAYOUT)) {
 148         if (req->elem.out_num) {
 149             req_size = req->elem.out_sg[0].iov_len;
 150         }
 151         if (req->elem.in_num) {
 152             resp_size = req->elem.in_sg[0].iov_len;
 153         }
 154     }
 155
 156     out_size = qemu_sgl_concat(req, req->elem.out_sg,
 157                                &req->elem.out_addr[0], req->elem.out_num,
 158                                req_size);
 159     in_size = qemu_sgl_concat(req, req->elem.in_sg,
 160                               &req->elem.in_addr[0], req->elem.in_num,
 161                               resp_size);
 162
 163     if (out_size && in_size) {
 164         return -ENOTSUP;
 165     }
 166
 167     if (out_size) {
 168         req->mode = SCSI_XFER_TO_DEV;
 169     } else if (in_size) {
 170         req->mode = SCSI_XFER_FROM_DEV;
 171     }
 172
 173     return 0;
 174 }
 175
 176 static VirtIOSCSIReq *virtio_scsi_pop_req(VirtIOSCSI *s, VirtQueue *vq)
 177 {
 178     VirtIOSCSICommon *vs = (VirtIOSCSICommon *)s;
 179     VirtIOSCSIReq *req;
 180
 181     req = virtqueue_pop(vq, sizeof(VirtIOSCSIReq) + vs->cdb_size);
 182     if (!req) {
 183         return NULL;
 184     }
 185     virtio_scsi_init_req(s, vq, req);
 186     return req;
 187 }
 188
 189 static void virtio_scsi_save_request(QEMUFile *f, SCSIRequest *sreq)
 190 {
 191     VirtIOSCSIReq *req = sreq->hba_private;
 192     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(req->dev);
 193     uint32_t n = virtio_get_queue_index(req->vq) - 2;
 194
 195     assert(n < vs->conf.num_queues);
 196     qemu_put_be32s(f, &n);
 197     qemu_put_virtqueue_element(f, &req->elem);
 198 }
 199
 200 static void *virtio_scsi_load_request(QEMUFile *f, SCSIRequest *sreq)
 201 {
 202     SCSIBus *bus = sreq->bus;
 203     VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
 204     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
 205     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 206     VirtIOSCSIReq *req;
 207     uint32_t n;
 208
 209     qemu_get_be32s(f, &n);
 210     assert(n < vs->conf.num_queues);
 211     req = qemu_get_virtqueue_element(vdev, f,
 212                                      sizeof(VirtIOSCSIReq) + vs->cdb_size);
 213     virtio_scsi_init_req(s, vs->cmd_vqs[n], req);
 214
 215     if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICmdReq) + vs->cdb_size,
 216                               sizeof(VirtIOSCSICmdResp) + vs->sense_size) < 0) {
 217         error_report("invalid SCSI request migration data");
 218         exit(1);
 219     }
 220
 221     scsi_req_ref(sreq);
 222     req->sreq = sreq;
 223     if (req->sreq->cmd.mode != SCSI_XFER_NONE) {
 224         assert(req->sreq->cmd.mode == req->mode);
 225     }
 226     return req;
 227 }
 228
 229 typedef struct {
 230     Notifier        notifier;
 231     VirtIOSCSIReq  *tmf_req;
 232 } VirtIOSCSICancelNotifier;
 233
 234 static void virtio_scsi_cancel_notify(Notifier *notifier, void *data)
 235 {
 236     VirtIOSCSICancelNotifier *n = container_of(notifier,
 237                                                VirtIOSCSICancelNotifier,
 238                                                notifier);
 239
 240     if (--n->tmf_req->remaining == 0) {
 241         virtio_scsi_complete_req(n->tmf_req);
 242     }
 243     g_free(n);
 244 }
 245
 246 static inline void virtio_scsi_ctx_check(VirtIOSCSI *s, SCSIDevice *d)
 247 {
 248     if (s->dataplane_started && d && blk_is_available(d->conf.blk)) {
 249         assert(blk_get_aio_context(d->conf.blk) == s->ctx);
 250     }
 251 }
 252
 253 /* Return 0 if the request is ready to be completed and return to guest;
 254  * -EINPROGRESS if the request is submitted and will be completed later, in the
 255  *  case of async cancellation. */
 256 static int virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req)
 257 {
 258     SCSIDevice *d = virtio_scsi_device_find(s, req->req.tmf.lun);
 259     SCSIRequest *r, *next;
 260     BusChild *kid;
 261     int target;
 262     int ret = 0;
 263
 264     virtio_scsi_ctx_check(s, d);
 265     /* Here VIRTIO_SCSI_S_OK means "FUNCTION COMPLETE".  */
 266     req->resp.tmf.response = VIRTIO_SCSI_S_OK;
 267
 268     /*
 269      * req->req.tmf has the QEMU_PACKED attribute. Don't use virtio_tswap32s()
 270      * to avoid compiler errors.
 271      */
 272     req->req.tmf.subtype =
 273         virtio_tswap32(VIRTIO_DEVICE(s), req->req.tmf.subtype);
 274
 275     switch (req->req.tmf.subtype) {
 276     case VIRTIO_SCSI_T_TMF_ABORT_TASK:
 277     case VIRTIO_SCSI_T_TMF_QUERY_TASK:
 278         if (!d) {
 279             goto fail;
 280         }
 281         if (d->lun != virtio_scsi_get_lun(req->req.tmf.lun)) {
 282             goto incorrect_lun;
 283         }
 284         QTAILQ_FOREACH_SAFE(r, &d->requests, next, next) {
 285             VirtIOSCSIReq *cmd_req = r->hba_private;
 286             if (cmd_req && cmd_req->req.cmd.tag == req->req.tmf.tag) {
 287                 break;
 288             }
 289         }
 290         if (r) {
 291             /*
 292              * Assert that the request has not been completed yet, we
 293              * check for it in the loop above.
 294              */
 295             assert(r->hba_private);
 296             if (req->req.tmf.subtype == VIRTIO_SCSI_T_TMF_QUERY_TASK) {
 297                 /* "If the specified command is present in the task set, then
 298                  * return a service response set to FUNCTION SUCCEEDED".
 299                  */
 300                 req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
 301             } else {
 302                 VirtIOSCSICancelNotifier *notifier;
 303
 304                 req->remaining = 1;
 305                 notifier = g_new(VirtIOSCSICancelNotifier, 1);
 306                 notifier->tmf_req = req;
 307                 notifier->notifier.notify = virtio_scsi_cancel_notify;
 308                 scsi_req_cancel_async(r, &notifier->notifier);
 309                 ret = -EINPROGRESS;
 310             }
 311         }
 312         break;
 313
 314     case VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET:
 315         if (!d) {
 316             goto fail;
 317         }
 318         if (d->lun != virtio_scsi_get_lun(req->req.tmf.lun)) {
 319             goto incorrect_lun;
 320         }
 321         s->resetting++;
 322         qdev_reset_all(&d->qdev);
 323         s->resetting--;
 324         break;
 325
 326     case VIRTIO_SCSI_T_TMF_ABORT_TASK_SET:
 327     case VIRTIO_SCSI_T_TMF_CLEAR_TASK_SET:
 328     case VIRTIO_SCSI_T_TMF_QUERY_TASK_SET:
 329         if (!d) {
 330             goto fail;
 331         }
 332         if (d->lun != virtio_scsi_get_lun(req->req.tmf.lun)) {
 333             goto incorrect_lun;
 334         }
 335
 336         /* Add 1 to "remaining" until virtio_scsi_do_tmf returns.
 337          * This way, if the bus starts calling back to the notifiers
 338          * even before we finish the loop, virtio_scsi_cancel_notify
 339          * will not complete the TMF too early.
 340          */
 341         req->remaining = 1;
 342         QTAILQ_FOREACH_SAFE(r, &d->requests, next, next) {
 343             if (r->hba_private) {
 344                 if (req->req.tmf.subtype == VIRTIO_SCSI_T_TMF_QUERY_TASK_SET) {
 345                     /* "If there is any command present in the task set, then
 346                      * return a service response set to FUNCTION SUCCEEDED".
 347                      */
 348                     req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
 349                     break;
 350                 } else {
 351                     VirtIOSCSICancelNotifier *notifier;
 352
 353                     req->remaining++;
 354                     notifier = g_new(VirtIOSCSICancelNotifier, 1);
 355                     notifier->notifier.notify = virtio_scsi_cancel_notify;
 356                     notifier->tmf_req = req;
 357                     scsi_req_cancel_async(r, &notifier->notifier);
 358                 }
 359             }
 360         }
 361         if (--req->remaining > 0) {
 362             ret = -EINPROGRESS;
 363         }
 364         break;
 365
 366     case VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET:
 367         target = req->req.tmf.lun[1];
 368         s->resetting++;
 369         QTAILQ_FOREACH(kid, &s->bus.qbus.children, sibling) {
 370              d = SCSI_DEVICE(kid->child);
 371              if (d->channel == 0 && d->id == target) {
 372                 qdev_reset_all(&d->qdev);
 373              }
 374         }
 375         s->resetting--;
 376         break;
 377
 378     case VIRTIO_SCSI_T_TMF_CLEAR_ACA:
 379     default:
 380         req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_REJECTED;
 381         break;
 382     }
 383
 384     return ret;
 385
 386 incorrect_lun:
 387     req->resp.tmf.response = VIRTIO_SCSI_S_INCORRECT_LUN;
 388     return ret;
 389
 390 fail:
 391     req->resp.tmf.response = VIRTIO_SCSI_S_BAD_TARGET;
 392     return ret;
 393 }
 394
 395 static void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s, VirtIOSCSIReq *req)
 396 {
 397     VirtIODevice *vdev = (VirtIODevice *)s;
 398     uint32_t type;
 399     int r = 0;
 400
 401     if (iov_to_buf(req->elem.out_sg, req->elem.out_num, 0,
 402                 &type, sizeof(type)) < sizeof(type)) {
 403         virtio_scsi_bad_req(req);
 404         return;
 405     }
 406
 407     virtio_tswap32s(vdev, &type);
 408     if (type == VIRTIO_SCSI_T_TMF) {
 409         if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICtrlTMFReq),
 410                     sizeof(VirtIOSCSICtrlTMFResp)) < 0) {
 411             virtio_scsi_bad_req(req);
 412             return;
 413         } else {
 414             r = virtio_scsi_do_tmf(s, req);
 415         }
 416
 417     } else if (type == VIRTIO_SCSI_T_AN_QUERY ||
 418                type == VIRTIO_SCSI_T_AN_SUBSCRIBE) {
 419         if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICtrlANReq),
 420                     sizeof(VirtIOSCSICtrlANResp)) < 0) {
 421             virtio_scsi_bad_req(req);
 422             return;
 423         } else {
 424             req->resp.an.event_actual = 0;
 425             req->resp.an.response = VIRTIO_SCSI_S_OK;
 426         }
 427     }
 428     if (r == 0) {
 429         virtio_scsi_complete_req(req);
 430     } else {
 431         assert(r == -EINPROGRESS);
 432     }
 433 }
 434
 435 bool virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq)
 436 {
 437     VirtIOSCSIReq *req;
 438     bool progress = false;
 439
 440     while ((req = virtio_scsi_pop_req(s, vq))) {
 441         progress = true;
 442         virtio_scsi_handle_ctrl_req(s, req);
 443     }
 444     return progress;
 445 }
 446
 447 static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
 448 {
 449     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
 450
 451     if (s->ctx) {
 452         virtio_device_start_ioeventfd(vdev);
 453         if (!s->dataplane_fenced) {
 454             return;
 455         }
 456     }
 457     virtio_scsi_acquire(s);
 458     virtio_scsi_handle_ctrl_vq(s, vq);
 459     virtio_scsi_release(s);
 460 }
 461
 462 static void virtio_scsi_complete_cmd_req(VirtIOSCSIReq *req)
 463 {
 464     /* Sense data is not in req->resp and is copied separately
 465      * in virtio_scsi_command_complete.
 466      */
 467     req->resp_size = sizeof(VirtIOSCSICmdResp);
 468     virtio_scsi_complete_req(req);
 469 }
 470
 471 static void virtio_scsi_command_complete(SCSIRequest *r, uint32_t status,
 472                                          size_t resid)
 473 {
 474     VirtIOSCSIReq *req = r->hba_private;
 475     uint8_t sense[SCSI_SENSE_BUF_SIZE];
 476     uint32_t sense_len;
 477     VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
 478
 479     if (r->io_canceled) {
 480         return;
 481     }
 482
 483     req->resp.cmd.response = VIRTIO_SCSI_S_OK;
 484     req->resp.cmd.status = status;
 485     if (req->resp.cmd.status == GOOD) {
 486         req->resp.cmd.resid = virtio_tswap32(vdev, resid);
 487     } else {
 488         req->resp.cmd.resid = 0;
 489         sense_len = scsi_req_get_sense(r, sense, sizeof(sense));
 490         sense_len = MIN(sense_len, req->resp_iov.size - sizeof(req->resp.cmd));
 491         qemu_iovec_from_buf(&req->resp_iov, sizeof(req->resp.cmd),
 492                             sense, sense_len);
 493         req->resp.cmd.sense_len = virtio_tswap32(vdev, sense_len);
 494     }
 495     virtio_scsi_complete_cmd_req(req);
 496 }
 497
 498 static int virtio_scsi_parse_cdb(SCSIDevice *dev, SCSICommand *cmd,
 499                                  uint8_t *buf, void *hba_private)
 500 {
 501     VirtIOSCSIReq *req = hba_private;
 502
 503     if (cmd->len == 0) {
 504         cmd->len = MIN(VIRTIO_SCSI_CDB_DEFAULT_SIZE, SCSI_CMD_BUF_SIZE);
 505         memcpy(cmd->buf, buf, cmd->len);
 506     }
 507
 508     /* Extract the direction and mode directly from the request, for
 509      * host device passthrough.
 510      */
 511     cmd->xfer = req->qsgl.size;
 512     cmd->mode = req->mode;
 513     return 0;
 514 }
 515
 516 static QEMUSGList *virtio_scsi_get_sg_list(SCSIRequest *r)
 517 {
 518     VirtIOSCSIReq *req = r->hba_private;
 519
 520     return &req->qsgl;
 521 }
 522
 523 static void virtio_scsi_request_cancelled(SCSIRequest *r)
 524 {
 525     VirtIOSCSIReq *req = r->hba_private;
 526
 527     if (!req) {
 528         return;
 529     }
 530     if (req->dev->resetting) {
 531         req->resp.cmd.response = VIRTIO_SCSI_S_RESET;
 532     } else {
 533         req->resp.cmd.response = VIRTIO_SCSI_S_ABORTED;
 534     }
 535     virtio_scsi_complete_cmd_req(req);
 536 }
 537
 538 static void virtio_scsi_fail_cmd_req(VirtIOSCSIReq *req)
 539 {
 540     req->resp.cmd.response = VIRTIO_SCSI_S_FAILURE;
 541     virtio_scsi_complete_cmd_req(req);
 542 }
 543
 544 static int virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, VirtIOSCSIReq *req)
 545 {
 546     VirtIOSCSICommon *vs = &s->parent_obj;
 547     SCSIDevice *d;
 548     int rc;
 549
 550     rc = virtio_scsi_parse_req(req, sizeof(VirtIOSCSICmdReq) + vs->cdb_size,
 551                                sizeof(VirtIOSCSICmdResp) + vs->sense_size);
 552     if (rc < 0) {
 553         if (rc == -ENOTSUP) {
 554             virtio_scsi_fail_cmd_req(req);
 555             return -ENOTSUP;
 556         } else {
 557             virtio_scsi_bad_req(req);
 558             return -EINVAL;
 559         }
 560     }
 561
 562     d = virtio_scsi_device_find(s, req->req.cmd.lun);
 563     if (!d) {
 564         req->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
 565         virtio_scsi_complete_cmd_req(req);
 566         return -ENOENT;
 567     }
 568     virtio_scsi_ctx_check(s, d);
 569     req->sreq = scsi_req_new(d, req->req.cmd.tag,
 570                              virtio_scsi_get_lun(req->req.cmd.lun),
 571                              req->req.cmd.cdb, req);
 572
 573     if (req->sreq->cmd.mode != SCSI_XFER_NONE
 574         && (req->sreq->cmd.mode != req->mode ||
 575             req->sreq->cmd.xfer > req->qsgl.size)) {
 576         req->resp.cmd.response = VIRTIO_SCSI_S_OVERRUN;
 577         virtio_scsi_complete_cmd_req(req);
 578         return -ENOBUFS;
 579     }
 580     scsi_req_ref(req->sreq);
 581     blk_io_plug(d->conf.blk);
 582     return 0;
 583 }
 584
 585 static void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI *s, VirtIOSCSIReq *req)
 586 {
 587     SCSIRequest *sreq = req->sreq;
 588     if (scsi_req_enqueue(sreq)) {
 589         scsi_req_continue(sreq);
 590     }
 591     blk_io_unplug(sreq->dev->conf.blk);
 592     scsi_req_unref(sreq);
 593 }
 594
 595 bool virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
 596 {
 597     VirtIOSCSIReq *req, *next;
 598     int ret = 0;
 599     bool progress = false;
 600
 601     QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs);
 602
 603     do {
 604         virtio_queue_set_notification(vq, 0);
 605
 606         while ((req = virtio_scsi_pop_req(s, vq))) {
 607             progress = true;
 608             ret = virtio_scsi_handle_cmd_req_prepare(s, req);
 609             if (!ret) {
 610                 QTAILQ_INSERT_TAIL(&reqs, req, next);
 611             } else if (ret == -EINVAL) {
 612                 /* The device is broken and shouldn't process any request */
 613                 while (!QTAILQ_EMPTY(&reqs)) {
 614                     req = QTAILQ_FIRST(&reqs);
 615                     QTAILQ_REMOVE(&reqs, req, next);
 616                     blk_io_unplug(req->sreq->dev->conf.blk);
 617                     scsi_req_unref(req->sreq);
 618                     virtqueue_detach_element(req->vq, &req->elem, 0);
 619                     virtio_scsi_free_req(req);
 620                 }
 621             }
 622         }
 623
 624         virtio_queue_set_notification(vq, 1);
 625     } while (ret != -EINVAL && !virtio_queue_empty(vq));
 626
 627     QTAILQ_FOREACH_SAFE(req, &reqs, next, next) {
 628         virtio_scsi_handle_cmd_req_submit(s, req);
 629     }
 630     return progress;
 631 }
 632
 633 static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)
 634 {
 635     /* use non-QOM casts in the data path */
 636     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
 637
 638     if (s->ctx) {
 639         virtio_device_start_ioeventfd(vdev);
 640         if (!s->dataplane_fenced) {
 641             return;
 642         }
 643     }
 644     virtio_scsi_acquire(s);
 645     virtio_scsi_handle_cmd_vq(s, vq);
 646     virtio_scsi_release(s);
 647 }
 648
 649 static void virtio_scsi_get_config(VirtIODevice *vdev,
 650                                    uint8_t *config)
 651 {
 652     VirtIOSCSIConfig *scsiconf = (VirtIOSCSIConfig *)config;
 653     VirtIOSCSICommon *s = VIRTIO_SCSI_COMMON(vdev);
 654
 655     virtio_stl_p(vdev, &scsiconf->num_queues, s->conf.num_queues);
 656     virtio_stl_p(vdev, &scsiconf->seg_max, 128 - 2);
 657     virtio_stl_p(vdev, &scsiconf->max_sectors, s->conf.max_sectors);
 658     virtio_stl_p(vdev, &scsiconf->cmd_per_lun, s->conf.cmd_per_lun);
 659     virtio_stl_p(vdev, &scsiconf->event_info_size, sizeof(VirtIOSCSIEvent));
 660     virtio_stl_p(vdev, &scsiconf->sense_size, s->sense_size);
 661     virtio_stl_p(vdev, &scsiconf->cdb_size, s->cdb_size);
 662     virtio_stw_p(vdev, &scsiconf->max_channel, VIRTIO_SCSI_MAX_CHANNEL);
 663     virtio_stw_p(vdev, &scsiconf->max_target, VIRTIO_SCSI_MAX_TARGET);
 664     virtio_stl_p(vdev, &scsiconf->max_lun, VIRTIO_SCSI_MAX_LUN);
 665 }
 666
 667 static void virtio_scsi_set_config(VirtIODevice *vdev,
 668                                    const uint8_t *config)
 669 {
 670     VirtIOSCSIConfig *scsiconf = (VirtIOSCSIConfig *)config;
 671     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
 672
 673     if ((uint32_t) virtio_ldl_p(vdev, &scsiconf->sense_size) >= 65536 ||
 674         (uint32_t) virtio_ldl_p(vdev, &scsiconf->cdb_size) >= 256) {
 675         virtio_error(vdev,
 676                      "bad data written to virtio-scsi configuration space");
 677         return;
 678     }
 679
 680     vs->sense_size = virtio_ldl_p(vdev, &scsiconf->sense_size);
 681     vs->cdb_size = virtio_ldl_p(vdev, &scsiconf->cdb_size);
 682 }
 683
 684 static uint64_t virtio_scsi_get_features(VirtIODevice *vdev,
 685                                          uint64_t requested_features,
 686                                          Error **errp)
 687 {
 688     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
 689
 690     /* Firstly sync all virtio-scsi possible supported features */
 691     requested_features |= s->host_features;
 692     return requested_features;
 693 }
 694
 695 static void virtio_scsi_reset(VirtIODevice *vdev)
 696 {
 697     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
 698     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
 699
 700     assert(!s->dataplane_started);
 701     s->resetting++;
 702     qbus_reset_all(BUS(&s->bus));
 703     s->resetting--;
 704
 705     vs->sense_size = VIRTIO_SCSI_SENSE_DEFAULT_SIZE;
 706     vs->cdb_size = VIRTIO_SCSI_CDB_DEFAULT_SIZE;
 707     s->events_dropped = false;
 708 }
 709
 710 void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev,
 711                             uint32_t event, uint32_t reason)
 712 {
 713     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
 714     VirtIOSCSIReq *req;
 715     VirtIOSCSIEvent *evt;
 716     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 717
 718     if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 719         return;
 720     }
 721
 722     req = virtio_scsi_pop_req(s, vs->event_vq);
 723     if (!req) {
 724         s->events_dropped = true;
 725         return;
 726     }
 727
 728     if (s->events_dropped) {
 729         event |= VIRTIO_SCSI_T_EVENTS_MISSED;
 730         s->events_dropped = false;
 731     }
 732
 733     if (virtio_scsi_parse_req(req, 0, sizeof(VirtIOSCSIEvent))) {
 734         virtio_scsi_bad_req(req);
 735         return;
 736     }
 737
 738     evt = &req->resp.event;
 739     memset(evt, 0, sizeof(VirtIOSCSIEvent));
 740     evt->event = virtio_tswap32(vdev, event);
 741     evt->reason = virtio_tswap32(vdev, reason);
 742     if (!dev) {
 743         assert(event == VIRTIO_SCSI_T_EVENTS_MISSED);
 744     } else {
 745         evt->lun[0] = 1;
 746         evt->lun[1] = dev->id;
 747
 748         /* Linux wants us to keep the same encoding we use for REPORT LUNS.  */
 749         if (dev->lun >= 256) {
 750             evt->lun[2] = (dev->lun >> 8) | 0x40;
 751         }
 752         evt->lun[3] = dev->lun & 0xFF;
 753     }
 754     virtio_scsi_complete_req(req);
 755 }
 756
 757 bool virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq)
 758 {
 759     if (s->events_dropped) {
 760         virtio_scsi_push_event(s, NULL, VIRTIO_SCSI_T_NO_EVENT, 0);
 761         return true;
 762     }
 763     return false;
 764 }
 765
 766 static void virtio_scsi_handle_event(VirtIODevice *vdev, VirtQueue *vq)
 767 {
 768     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
 769
 770     if (s->ctx) {
 771         virtio_device_start_ioeventfd(vdev);
 772         if (!s->dataplane_fenced) {
 773             return;
 774         }
 775     }
 776     virtio_scsi_acquire(s);
 777     virtio_scsi_handle_event_vq(s, vq);
 778     virtio_scsi_release(s);
 779 }
 780
 781 static void virtio_scsi_change(SCSIBus *bus, SCSIDevice *dev, SCSISense sense)
 782 {
 783     VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
 784     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 785
 786     if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_CHANGE) &&
 787         dev->type != TYPE_ROM) {
 788         virtio_scsi_acquire(s);
 789         virtio_scsi_push_event(s, dev, VIRTIO_SCSI_T_PARAM_CHANGE,
 790                                sense.asc | (sense.ascq << 8));
 791         virtio_scsi_release(s);
 792     }
 793 }
 794
 795 static void virtio_scsi_pre_hotplug(HotplugHandler *hotplug_dev,
 796                                     DeviceState *dev, Error **errp)
 797 {
 798     SCSIDevice *sd = SCSI_DEVICE(dev);
 799     sd->hba_supports_iothread = true;
 800 }
 801
 802 static void virtio_scsi_hotplug(HotplugHandler *hotplug_dev, DeviceState *dev,
 803                                 Error **errp)
 804 {
 805     VirtIODevice *vdev = VIRTIO_DEVICE(hotplug_dev);
 806     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
 807     SCSIDevice *sd = SCSI_DEVICE(dev);
 808     int ret;
 809
 810     if (s->ctx && !s->dataplane_fenced) {
 811         if (blk_op_is_blocked(sd->conf.blk, BLOCK_OP_TYPE_DATAPLANE, errp)) {
 812             return;
 813         }
 814         virtio_scsi_acquire(s);
 815         ret = blk_set_aio_context(sd->conf.blk, s->ctx, errp);
 816         virtio_scsi_release(s);
 817         if (ret < 0) {
 818             return;
 819         }
 820     }
 821
 822     if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) {
 823         virtio_scsi_acquire(s);
 824         virtio_scsi_push_event(s, sd,
 825                                VIRTIO_SCSI_T_TRANSPORT_RESET,
 826                                VIRTIO_SCSI_EVT_RESET_RESCAN);
 827         virtio_scsi_release(s);
 828     }
 829 }
 830
 831 static void virtio_scsi_hotunplug(HotplugHandler *hotplug_dev, DeviceState *dev,
 832                                   Error **errp)
 833 {
 834     VirtIODevice *vdev = VIRTIO_DEVICE(hotplug_dev);
 835     VirtIOSCSI *s = VIRTIO_SCSI(vdev);
 836     SCSIDevice *sd = SCSI_DEVICE(dev);
 837     AioContext *ctx = s->ctx ?: qemu_get_aio_context();
 838
 839     if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) {
 840         virtio_scsi_acquire(s);
 841         virtio_scsi_push_event(s, sd,
 842                                VIRTIO_SCSI_T_TRANSPORT_RESET,
 843                                VIRTIO_SCSI_EVT_RESET_REMOVED);
 844         virtio_scsi_release(s);
 845     }
 846
 847     aio_disable_external(ctx);
 848     qdev_simple_device_unplug_cb(hotplug_dev, dev, errp);
 849     aio_enable_external(ctx);
 850
 851     if (s->ctx) {
 852         virtio_scsi_acquire(s);
 853         /* If other users keep the BlockBackend in the iothread, that's ok */
 854         blk_set_aio_context(sd->conf.blk, qemu_get_aio_context(), NULL);
 855         virtio_scsi_release(s);
 856     }
 857 }
 858
 859 static struct SCSIBusInfo virtio_scsi_scsi_info = {
 860     .tcq = true,
 861     .max_channel = VIRTIO_SCSI_MAX_CHANNEL,
 862     .max_target = VIRTIO_SCSI_MAX_TARGET,
 863     .max_lun = VIRTIO_SCSI_MAX_LUN,
 864
 865     .complete = virtio_scsi_command_complete,
 866     .cancel = virtio_scsi_request_cancelled,
 867     .change = virtio_scsi_change,
 868     .parse_cdb = virtio_scsi_parse_cdb,
 869     .get_sg_list = virtio_scsi_get_sg_list,
 870     .save_request = virtio_scsi_save_request,
 871     .load_request = virtio_scsi_load_request,
 872 };
 873
 874 void virtio_scsi_common_realize(DeviceState *dev,
 875                                 VirtIOHandleOutput ctrl,
 876                                 VirtIOHandleOutput evt,
 877                                 VirtIOHandleOutput cmd,
 878                                 Error **errp)
 879 {
 880     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 881     VirtIOSCSICommon *s = VIRTIO_SCSI_COMMON(dev);
 882     int i;
 883
 884     virtio_init(vdev, "virtio-scsi", VIRTIO_ID_SCSI,
 885                 sizeof(VirtIOSCSIConfig));
 886
 887     if (s->conf.num_queues == 0 ||
 888             s->conf.num_queues > VIRTIO_QUEUE_MAX - 2) {
 889         error_setg(errp, "Invalid number of queues (= %" PRIu32 "), "
 890                          "must be a positive integer less than %d.",
 891                    s->conf.num_queues, VIRTIO_QUEUE_MAX - 2);
 892         virtio_cleanup(vdev);
 893         return;
 894     }
 895     s->cmd_vqs = g_new0(VirtQueue *, s->conf.num_queues);
 896     s->sense_size = VIRTIO_SCSI_SENSE_DEFAULT_SIZE;
 897     s->cdb_size = VIRTIO_SCSI_CDB_DEFAULT_SIZE;
 898
 899     s->ctrl_vq = virtio_add_queue(vdev, s->conf.virtqueue_size, ctrl);
 900     s->event_vq = virtio_add_queue(vdev, s->conf.virtqueue_size, evt);
 901     for (i = 0; i < s->conf.num_queues; i++) {
 902         s->cmd_vqs[i] = virtio_add_queue(vdev, s->conf.virtqueue_size, cmd);
 903     }
 904 }
 905
 906 static void virtio_scsi_device_realize(DeviceState *dev, Error **errp)
 907 {
 908     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 909     VirtIOSCSI *s = VIRTIO_SCSI(dev);
 910     Error *err = NULL;
 911
 912     virtio_scsi_common_realize(dev,
 913                                virtio_scsi_handle_ctrl,
 914                                virtio_scsi_handle_event,
 915                                virtio_scsi_handle_cmd,
 916                                &err);
 917     if (err != NULL) {
 918         error_propagate(errp, err);
 919         return;
 920     }
 921
 922     scsi_bus_new(&s->bus, sizeof(s->bus), dev,
 923                  &virtio_scsi_scsi_info, vdev->bus_name);
 924     /* override default SCSI bus hotplug-handler, with virtio-scsi's one */
 925     qbus_set_hotplug_handler(BUS(&s->bus), OBJECT(dev), &error_abort);
 926
 927     virtio_scsi_dataplane_setup(s, errp);
 928 }
 929
 930 void virtio_scsi_common_unrealize(DeviceState *dev)
 931 {
 932     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 933     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(dev);
 934
 935     g_free(vs->cmd_vqs);
 936     virtio_cleanup(vdev);
 937 }
 938
 939 static void virtio_scsi_device_unrealize(DeviceState *dev, Error **errp)
 940 {
 941     VirtIOSCSI *s = VIRTIO_SCSI(dev);
 942
 943     qbus_set_hotplug_handler(BUS(&s->bus), NULL, &error_abort);
 944     virtio_scsi_common_unrealize(dev);
 945 }
 946
 947 static Property virtio_scsi_properties[] = {
 948     DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues, 1),
 949     DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSI,
 950                                          parent_obj.conf.virtqueue_size, 128),
 951     DEFINE_PROP_UINT32("max_sectors", VirtIOSCSI, parent_obj.conf.max_sectors,
 952                                                   0xFFFF),
 953     DEFINE_PROP_UINT32("cmd_per_lun", VirtIOSCSI, parent_obj.conf.cmd_per_lun,
 954                                                   128),
 955     DEFINE_PROP_BIT("hotplug", VirtIOSCSI, host_features,
 956                                            VIRTIO_SCSI_F_HOTPLUG, true),
 957     DEFINE_PROP_BIT("param_change", VirtIOSCSI, host_features,
 958                                                 VIRTIO_SCSI_F_CHANGE, true),
 959     DEFINE_PROP_LINK("iothread", VirtIOSCSI, parent_obj.conf.iothread,
 960                      TYPE_IOTHREAD, IOThread *),
 961     DEFINE_PROP_END_OF_LIST(),
 962 };
 963
 964 static const VMStateDescription vmstate_virtio_scsi = {
 965     .name = "virtio-scsi",
 966     .minimum_version_id = 1,
 967     .version_id = 1,
 968     .fields = (VMStateField[]) {
 969         VMSTATE_VIRTIO_DEVICE,
 970         VMSTATE_END_OF_LIST()
 971     },
 972 };
 973
 974 static void virtio_scsi_common_class_init(ObjectClass *klass, void *data)
 975 {
 976     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 977     DeviceClass *dc = DEVICE_CLASS(klass);
 978
 979     vdc->get_config = virtio_scsi_get_config;
 980     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 981 }
 982
 983 static void virtio_scsi_class_init(ObjectClass *klass, void *data)
 984 {
 985     DeviceClass *dc = DEVICE_CLASS(klass);
 986     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 987     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
 988
 989     dc->props = virtio_scsi_properties;
 990     dc->vmsd = &vmstate_virtio_scsi;
 991     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 992     vdc->realize = virtio_scsi_device_realize;
 993     vdc->unrealize = virtio_scsi_device_unrealize;
 994     vdc->set_config = virtio_scsi_set_config;
 995     vdc->get_features = virtio_scsi_get_features;
 996     vdc->reset = virtio_scsi_reset;
 997     vdc->start_ioeventfd = virtio_scsi_dataplane_start;
 998     vdc->stop_ioeventfd = virtio_scsi_dataplane_stop;
 999     hc->pre_plug = virtio_scsi_pre_hotplug;
1000     hc->plug = virtio_scsi_hotplug;
1001     hc->unplug = virtio_scsi_hotunplug;
1002 }
1003
1004 static const TypeInfo virtio_scsi_common_info = {
1005     .name = TYPE_VIRTIO_SCSI_COMMON,
1006     .parent = TYPE_VIRTIO_DEVICE,
1007     .instance_size = sizeof(VirtIOSCSICommon),
1008     .abstract = true,
1009     .class_init = virtio_scsi_common_class_init,
1010 };
1011
1012 static const TypeInfo virtio_scsi_info = {
1013     .name = TYPE_VIRTIO_SCSI,
1014     .parent = TYPE_VIRTIO_SCSI_COMMON,
1015     .instance_size = sizeof(VirtIOSCSI),
1016     .class_init = virtio_scsi_class_init,
1017     .interfaces = (InterfaceInfo[]) {
1018         { TYPE_HOTPLUG_HANDLER },
1019         { }
1020     }
1021 };
1022
1023 static void virtio_register_types(void)
1024 {
1025     type_register_static(&virtio_scsi_common_info);
1026     type_register_static(&virtio_scsi_info);
1027 }
1028
1029 type_init(virtio_register_types)