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