hw/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 "virtio-scsi.h"
  17 #include <hw/scsi.h>
  18 #include <hw/scsi-defs.h>
  19
  20 #define VIRTIO_SCSI_VQ_SIZE     128
  21 #define VIRTIO_SCSI_CDB_SIZE    32
  22 #define VIRTIO_SCSI_SENSE_SIZE  96
  23 #define VIRTIO_SCSI_MAX_CHANNEL 0
  24 #define VIRTIO_SCSI_MAX_TARGET  255
  25 #define VIRTIO_SCSI_MAX_LUN     16383
  26
  27 /* Response codes */
  28 #define VIRTIO_SCSI_S_OK                       0
  29 #define VIRTIO_SCSI_S_OVERRUN                  1
  30 #define VIRTIO_SCSI_S_ABORTED                  2
  31 #define VIRTIO_SCSI_S_BAD_TARGET               3
  32 #define VIRTIO_SCSI_S_RESET                    4
  33 #define VIRTIO_SCSI_S_BUSY                     5
  34 #define VIRTIO_SCSI_S_TRANSPORT_FAILURE        6
  35 #define VIRTIO_SCSI_S_TARGET_FAILURE           7
  36 #define VIRTIO_SCSI_S_NEXUS_FAILURE            8
  37 #define VIRTIO_SCSI_S_FAILURE                  9
  38 #define VIRTIO_SCSI_S_FUNCTION_SUCCEEDED       10
  39 #define VIRTIO_SCSI_S_FUNCTION_REJECTED        11
  40 #define VIRTIO_SCSI_S_INCORRECT_LUN            12
  41
  42 /* Controlq type codes.  */
  43 #define VIRTIO_SCSI_T_TMF                      0
  44 #define VIRTIO_SCSI_T_AN_QUERY                 1
  45 #define VIRTIO_SCSI_T_AN_SUBSCRIBE             2
  46
  47 /* Valid TMF subtypes.  */
  48 #define VIRTIO_SCSI_T_TMF_ABORT_TASK           0
  49 #define VIRTIO_SCSI_T_TMF_ABORT_TASK_SET       1
  50 #define VIRTIO_SCSI_T_TMF_CLEAR_ACA            2
  51 #define VIRTIO_SCSI_T_TMF_CLEAR_TASK_SET       3
  52 #define VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET      4
  53 #define VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET   5
  54 #define VIRTIO_SCSI_T_TMF_QUERY_TASK           6
  55 #define VIRTIO_SCSI_T_TMF_QUERY_TASK_SET       7
  56
  57 /* Events.  */
  58 #define VIRTIO_SCSI_T_EVENTS_MISSED            0x80000000
  59 #define VIRTIO_SCSI_T_NO_EVENT                 0
  60 #define VIRTIO_SCSI_T_TRANSPORT_RESET          1
  61 #define VIRTIO_SCSI_T_ASYNC_NOTIFY             2
  62 #define VIRTIO_SCSI_T_PARAM_CHANGE             3
  63
  64 /* Reasons for transport reset event */
  65 #define VIRTIO_SCSI_EVT_RESET_HARD             0
  66 #define VIRTIO_SCSI_EVT_RESET_RESCAN           1
  67 #define VIRTIO_SCSI_EVT_RESET_REMOVED          2
  68
  69 /* SCSI command request, followed by data-out */
  70 typedef struct {
  71     uint8_t lun[8];              /* Logical Unit Number */
  72     uint64_t tag;                /* Command identifier */
  73     uint8_t task_attr;           /* Task attribute */
  74     uint8_t prio;
  75     uint8_t crn;
  76     uint8_t cdb[];
  77 } QEMU_PACKED VirtIOSCSICmdReq;
  78
  79 /* Response, followed by sense data and data-in */
  80 typedef struct {
  81     uint32_t sense_len;          /* Sense data length */
  82     uint32_t resid;              /* Residual bytes in data buffer */
  83     uint16_t status_qualifier;   /* Status qualifier */
  84     uint8_t status;              /* Command completion status */
  85     uint8_t response;            /* Response values */
  86     uint8_t sense[];
  87 } QEMU_PACKED VirtIOSCSICmdResp;
  88
  89 /* Task Management Request */
  90 typedef struct {
  91     uint32_t type;
  92     uint32_t subtype;
  93     uint8_t lun[8];
  94     uint64_t tag;
  95 } QEMU_PACKED VirtIOSCSICtrlTMFReq;
  96
  97 typedef struct {
  98     uint8_t response;
  99 } QEMU_PACKED VirtIOSCSICtrlTMFResp;
 100
 101 /* Asynchronous notification query/subscription */
 102 typedef struct {
 103     uint32_t type;
 104     uint8_t lun[8];
 105     uint32_t event_requested;
 106 } QEMU_PACKED VirtIOSCSICtrlANReq;
 107
 108 typedef struct {
 109     uint32_t event_actual;
 110     uint8_t response;
 111 } QEMU_PACKED VirtIOSCSICtrlANResp;
 112
 113 typedef struct {
 114     uint32_t event;
 115     uint8_t lun[8];
 116     uint32_t reason;
 117 } QEMU_PACKED VirtIOSCSIEvent;
 118
 119 typedef struct {
 120     uint32_t num_queues;
 121     uint32_t seg_max;
 122     uint32_t max_sectors;
 123     uint32_t cmd_per_lun;
 124     uint32_t event_info_size;
 125     uint32_t sense_size;
 126     uint32_t cdb_size;
 127     uint16_t max_channel;
 128     uint16_t max_target;
 129     uint32_t max_lun;
 130 } QEMU_PACKED VirtIOSCSIConfig;
 131
 132 typedef struct {
 133     VirtIODevice vdev;
 134     DeviceState *qdev;
 135     VirtIOSCSIConf *conf;
 136
 137     SCSIBus bus;
 138     uint32_t sense_size;
 139     uint32_t cdb_size;
 140     int resetting;
 141     bool events_dropped;
 142     VirtQueue *ctrl_vq;
 143     VirtQueue *event_vq;
 144     VirtQueue *cmd_vqs[0];
 145 } VirtIOSCSI;
 146
 147 typedef struct VirtIOSCSIReq {
 148     VirtIOSCSI *dev;
 149     VirtQueue *vq;
 150     VirtQueueElement elem;
 151     QEMUSGList qsgl;
 152     SCSIRequest *sreq;
 153     union {
 154         char                  *buf;
 155         VirtIOSCSICmdReq      *cmd;
 156         VirtIOSCSICtrlTMFReq  *tmf;
 157         VirtIOSCSICtrlANReq   *an;
 158     } req;
 159     union {
 160         char                  *buf;
 161         VirtIOSCSICmdResp     *cmd;
 162         VirtIOSCSICtrlTMFResp *tmf;
 163         VirtIOSCSICtrlANResp  *an;
 164         VirtIOSCSIEvent       *event;
 165     } resp;
 166 } VirtIOSCSIReq;
 167
 168 static inline int virtio_scsi_get_lun(uint8_t *lun)
 169 {
 170     return ((lun[2] << 8) | lun[3]) & 0x3FFF;
 171 }
 172
 173 static inline SCSIDevice *virtio_scsi_device_find(VirtIOSCSI *s, uint8_t *lun)
 174 {
 175     if (lun[0] != 1) {
 176         return NULL;
 177     }
 178     if (lun[2] != 0 && !(lun[2] >= 0x40 && lun[2] < 0x80)) {
 179         return NULL;
 180     }
 181     return scsi_device_find(&s->bus, 0, lun[1], virtio_scsi_get_lun(lun));
 182 }
 183
 184 static void virtio_scsi_complete_req(VirtIOSCSIReq *req)
 185 {
 186     VirtIOSCSI *s = req->dev;
 187     VirtQueue *vq = req->vq;
 188     virtqueue_push(vq, &req->elem, req->qsgl.size + req->elem.in_sg[0].iov_len);
 189     qemu_sglist_destroy(&req->qsgl);
 190     if (req->sreq) {
 191         req->sreq->hba_private = NULL;
 192         scsi_req_unref(req->sreq);
 193     }
 194     g_free(req);
 195     virtio_notify(&s->vdev, vq);
 196 }
 197
 198 static void virtio_scsi_bad_req(void)
 199 {
 200     error_report("wrong size for virtio-scsi headers");
 201     exit(1);
 202 }
 203
 204 static void qemu_sgl_init_external(QEMUSGList *qsgl, struct iovec *sg,
 205                                    hwaddr *addr, int num)
 206 {
 207     qemu_sglist_init(qsgl, num, &dma_context_memory);
 208     while (num--) {
 209         qemu_sglist_add(qsgl, *(addr++), (sg++)->iov_len);
 210     }
 211 }
 212
 213 static void virtio_scsi_parse_req(VirtIOSCSI *s, VirtQueue *vq,
 214                                   VirtIOSCSIReq *req)
 215 {
 216     assert(req->elem.in_num);
 217     req->vq = vq;
 218     req->dev = s;
 219     req->sreq = NULL;
 220     if (req->elem.out_num) {
 221         req->req.buf = req->elem.out_sg[0].iov_base;
 222     }
 223     req->resp.buf = req->elem.in_sg[0].iov_base;
 224
 225     if (req->elem.out_num > 1) {
 226         qemu_sgl_init_external(&req->qsgl, &req->elem.out_sg[1],
 227                                &req->elem.out_addr[1],
 228                                req->elem.out_num - 1);
 229     } else {
 230         qemu_sgl_init_external(&req->qsgl, &req->elem.in_sg[1],
 231                                &req->elem.in_addr[1],
 232                                req->elem.in_num - 1);
 233     }
 234 }
 235
 236 static VirtIOSCSIReq *virtio_scsi_pop_req(VirtIOSCSI *s, VirtQueue *vq)
 237 {
 238     VirtIOSCSIReq *req;
 239     req = g_malloc(sizeof(*req));
 240     if (!virtqueue_pop(vq, &req->elem)) {
 241         g_free(req);
 242         return NULL;
 243     }
 244
 245     virtio_scsi_parse_req(s, vq, req);
 246     return req;
 247 }
 248
 249 static void virtio_scsi_save_request(QEMUFile *f, SCSIRequest *sreq)
 250 {
 251     VirtIOSCSIReq *req = sreq->hba_private;
 252     uint32_t n = virtio_queue_get_id(req->vq) - 2;
 253
 254     assert(n < req->dev->conf->num_queues);
 255     qemu_put_be32s(f, &n);
 256     qemu_put_buffer(f, (unsigned char *)&req->elem, sizeof(req->elem));
 257 }
 258
 259 static void *virtio_scsi_load_request(QEMUFile *f, SCSIRequest *sreq)
 260 {
 261     SCSIBus *bus = sreq->bus;
 262     VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
 263     VirtIOSCSIReq *req;
 264     uint32_t n;
 265
 266     req = g_malloc(sizeof(*req));
 267     qemu_get_be32s(f, &n);
 268     assert(n < s->conf->num_queues);
 269     qemu_get_buffer(f, (unsigned char *)&req->elem, sizeof(req->elem));
 270     virtio_scsi_parse_req(s, s->cmd_vqs[n], req);
 271
 272     scsi_req_ref(sreq);
 273     req->sreq = sreq;
 274     if (req->sreq->cmd.mode != SCSI_XFER_NONE) {
 275         int req_mode =
 276             (req->elem.in_num > 1 ? SCSI_XFER_FROM_DEV : SCSI_XFER_TO_DEV);
 277
 278         assert(req->sreq->cmd.mode == req_mode);
 279     }
 280     return req;
 281 }
 282
 283 static void virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req)
 284 {
 285     SCSIDevice *d = virtio_scsi_device_find(s, req->req.tmf->lun);
 286     SCSIRequest *r, *next;
 287     BusChild *kid;
 288     int target;
 289
 290     /* Here VIRTIO_SCSI_S_OK means "FUNCTION COMPLETE".  */
 291     req->resp.tmf->response = VIRTIO_SCSI_S_OK;
 292
 293     switch (req->req.tmf->subtype) {
 294     case VIRTIO_SCSI_T_TMF_ABORT_TASK:
 295     case VIRTIO_SCSI_T_TMF_QUERY_TASK:
 296         if (!d) {
 297             goto fail;
 298         }
 299         if (d->lun != virtio_scsi_get_lun(req->req.tmf->lun)) {
 300             goto incorrect_lun;
 301         }
 302         QTAILQ_FOREACH_SAFE(r, &d->requests, next, next) {
 303             VirtIOSCSIReq *cmd_req = r->hba_private;
 304             if (cmd_req && cmd_req->req.cmd->tag == req->req.tmf->tag) {
 305                 break;
 306             }
 307         }
 308         if (r) {
 309             /*
 310              * Assert that the request has not been completed yet, we
 311              * check for it in the loop above.
 312              */
 313             assert(r->hba_private);
 314             if (req->req.tmf->subtype == VIRTIO_SCSI_T_TMF_QUERY_TASK) {
 315                 /* "If the specified command is present in the task set, then
 316                  * return a service response set to FUNCTION SUCCEEDED".
 317                  */
 318                 req->resp.tmf->response = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
 319             } else {
 320                 scsi_req_cancel(r);
 321             }
 322         }
 323         break;
 324
 325     case VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET:
 326         if (!d) {
 327             goto fail;
 328         }
 329         if (d->lun != virtio_scsi_get_lun(req->req.tmf->lun)) {
 330             goto incorrect_lun;
 331         }
 332         s->resetting++;
 333         qdev_reset_all(&d->qdev);
 334         s->resetting--;
 335         break;
 336
 337     case VIRTIO_SCSI_T_TMF_ABORT_TASK_SET:
 338     case VIRTIO_SCSI_T_TMF_CLEAR_TASK_SET:
 339     case VIRTIO_SCSI_T_TMF_QUERY_TASK_SET:
 340         if (!d) {
 341             goto fail;
 342         }
 343         if (d->lun != virtio_scsi_get_lun(req->req.tmf->lun)) {
 344             goto incorrect_lun;
 345         }
 346         QTAILQ_FOREACH_SAFE(r, &d->requests, next, next) {
 347             if (r->hba_private) {
 348                 if (req->req.tmf->subtype == VIRTIO_SCSI_T_TMF_QUERY_TASK_SET) {
 349                     /* "If there is any command present in the task set, then
 350                      * return a service response set to FUNCTION SUCCEEDED".
 351                      */
 352                     req->resp.tmf->response = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
 353                     break;
 354                 } else {
 355                     scsi_req_cancel(r);
 356                 }
 357             }
 358         }
 359         break;
 360
 361     case VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET:
 362         target = req->req.tmf->lun[1];
 363         s->resetting++;
 364         QTAILQ_FOREACH(kid, &s->bus.qbus.children, sibling) {
 365              d = DO_UPCAST(SCSIDevice, qdev, kid->child);
 366              if (d->channel == 0 && d->id == target) {
 367                 qdev_reset_all(&d->qdev);
 368              }
 369         }
 370         s->resetting--;
 371         break;
 372
 373     case VIRTIO_SCSI_T_TMF_CLEAR_ACA:
 374     default:
 375         req->resp.tmf->response = VIRTIO_SCSI_S_FUNCTION_REJECTED;
 376         break;
 377     }
 378
 379     return;
 380
 381 incorrect_lun:
 382     req->resp.tmf->response = VIRTIO_SCSI_S_INCORRECT_LUN;
 383     return;
 384
 385 fail:
 386     req->resp.tmf->response = VIRTIO_SCSI_S_BAD_TARGET;
 387 }
 388
 389 static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
 390 {
 391     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
 392     VirtIOSCSIReq *req;
 393
 394     while ((req = virtio_scsi_pop_req(s, vq))) {
 395         int out_size, in_size;
 396         if (req->elem.out_num < 1 || req->elem.in_num < 1) {
 397             virtio_scsi_bad_req();
 398             continue;
 399         }
 400
 401         out_size = req->elem.out_sg[0].iov_len;
 402         in_size = req->elem.in_sg[0].iov_len;
 403         if (req->req.tmf->type == VIRTIO_SCSI_T_TMF) {
 404             if (out_size < sizeof(VirtIOSCSICtrlTMFReq) ||
 405                 in_size < sizeof(VirtIOSCSICtrlTMFResp)) {
 406                 virtio_scsi_bad_req();
 407             }
 408             virtio_scsi_do_tmf(s, req);
 409
 410         } else if (req->req.tmf->type == VIRTIO_SCSI_T_AN_QUERY ||
 411                    req->req.tmf->type == VIRTIO_SCSI_T_AN_SUBSCRIBE) {
 412             if (out_size < sizeof(VirtIOSCSICtrlANReq) ||
 413                 in_size < sizeof(VirtIOSCSICtrlANResp)) {
 414                 virtio_scsi_bad_req();
 415             }
 416             req->resp.an->event_actual = 0;
 417             req->resp.an->response = VIRTIO_SCSI_S_OK;
 418         }
 419         virtio_scsi_complete_req(req);
 420     }
 421 }
 422
 423 static void virtio_scsi_command_complete(SCSIRequest *r, uint32_t status,
 424                                          size_t resid)
 425 {
 426     VirtIOSCSIReq *req = r->hba_private;
 427     uint32_t sense_len;
 428
 429     req->resp.cmd->response = VIRTIO_SCSI_S_OK;
 430     req->resp.cmd->status = status;
 431     if (req->resp.cmd->status == GOOD) {
 432         req->resp.cmd->resid = tswap32(resid);
 433     } else {
 434         req->resp.cmd->resid = 0;
 435         sense_len = scsi_req_get_sense(r, req->resp.cmd->sense,
 436                                        VIRTIO_SCSI_SENSE_SIZE);
 437         req->resp.cmd->sense_len = tswap32(sense_len);
 438     }
 439     virtio_scsi_complete_req(req);
 440 }
 441
 442 static QEMUSGList *virtio_scsi_get_sg_list(SCSIRequest *r)
 443 {
 444     VirtIOSCSIReq *req = r->hba_private;
 445
 446     return &req->qsgl;
 447 }
 448
 449 static void virtio_scsi_request_cancelled(SCSIRequest *r)
 450 {
 451     VirtIOSCSIReq *req = r->hba_private;
 452
 453     if (!req) {
 454         return;
 455     }
 456     if (req->dev->resetting) {
 457         req->resp.cmd->response = VIRTIO_SCSI_S_RESET;
 458     } else {
 459         req->resp.cmd->response = VIRTIO_SCSI_S_ABORTED;
 460     }
 461     virtio_scsi_complete_req(req);
 462 }
 463
 464 static void virtio_scsi_fail_cmd_req(VirtIOSCSIReq *req)
 465 {
 466     req->resp.cmd->response = VIRTIO_SCSI_S_FAILURE;
 467     virtio_scsi_complete_req(req);
 468 }
 469
 470 static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)
 471 {
 472     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
 473     VirtIOSCSIReq *req;
 474     int n;
 475
 476     while ((req = virtio_scsi_pop_req(s, vq))) {
 477         SCSIDevice *d;
 478         int out_size, in_size;
 479         if (req->elem.out_num < 1 || req->elem.in_num < 1) {
 480             virtio_scsi_bad_req();
 481         }
 482
 483         out_size = req->elem.out_sg[0].iov_len;
 484         in_size = req->elem.in_sg[0].iov_len;
 485         if (out_size < sizeof(VirtIOSCSICmdReq) + s->cdb_size ||
 486             in_size < sizeof(VirtIOSCSICmdResp) + s->sense_size) {
 487             virtio_scsi_bad_req();
 488         }
 489
 490         if (req->elem.out_num > 1 && req->elem.in_num > 1) {
 491             virtio_scsi_fail_cmd_req(req);
 492             continue;
 493         }
 494
 495         d = virtio_scsi_device_find(s, req->req.cmd->lun);
 496         if (!d) {
 497             req->resp.cmd->response = VIRTIO_SCSI_S_BAD_TARGET;
 498             virtio_scsi_complete_req(req);
 499             continue;
 500         }
 501         req->sreq = scsi_req_new(d, req->req.cmd->tag,
 502                                  virtio_scsi_get_lun(req->req.cmd->lun),
 503                                  req->req.cmd->cdb, req);
 504
 505         if (req->sreq->cmd.mode != SCSI_XFER_NONE) {
 506             int req_mode =
 507                 (req->elem.in_num > 1 ? SCSI_XFER_FROM_DEV : SCSI_XFER_TO_DEV);
 508
 509             if (req->sreq->cmd.mode != req_mode ||
 510                 req->sreq->cmd.xfer > req->qsgl.size) {
 511                 req->resp.cmd->response = VIRTIO_SCSI_S_OVERRUN;
 512                 virtio_scsi_complete_req(req);
 513                 continue;
 514             }
 515         }
 516
 517         n = scsi_req_enqueue(req->sreq);
 518         if (n) {
 519             scsi_req_continue(req->sreq);
 520         }
 521     }
 522 }
 523
 524 static void virtio_scsi_get_config(VirtIODevice *vdev,
 525                                    uint8_t *config)
 526 {
 527     VirtIOSCSIConfig *scsiconf = (VirtIOSCSIConfig *)config;
 528     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
 529
 530     stl_raw(&scsiconf->num_queues, s->conf->num_queues);
 531     stl_raw(&scsiconf->seg_max, 128 - 2);
 532     stl_raw(&scsiconf->max_sectors, s->conf->max_sectors);
 533     stl_raw(&scsiconf->cmd_per_lun, s->conf->cmd_per_lun);
 534     stl_raw(&scsiconf->event_info_size, sizeof(VirtIOSCSIEvent));
 535     stl_raw(&scsiconf->sense_size, s->sense_size);
 536     stl_raw(&scsiconf->cdb_size, s->cdb_size);
 537     stw_raw(&scsiconf->max_channel, VIRTIO_SCSI_MAX_CHANNEL);
 538     stw_raw(&scsiconf->max_target, VIRTIO_SCSI_MAX_TARGET);
 539     stl_raw(&scsiconf->max_lun, VIRTIO_SCSI_MAX_LUN);
 540 }
 541
 542 static void virtio_scsi_set_config(VirtIODevice *vdev,
 543                                    const uint8_t *config)
 544 {
 545     VirtIOSCSIConfig *scsiconf = (VirtIOSCSIConfig *)config;
 546     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
 547
 548     if ((uint32_t) ldl_raw(&scsiconf->sense_size) >= 65536 ||
 549         (uint32_t) ldl_raw(&scsiconf->cdb_size) >= 256) {
 550         error_report("bad data written to virtio-scsi configuration space");
 551         exit(1);
 552     }
 553
 554     s->sense_size = ldl_raw(&scsiconf->sense_size);
 555     s->cdb_size = ldl_raw(&scsiconf->cdb_size);
 556 }
 557
 558 static uint32_t virtio_scsi_get_features(VirtIODevice *vdev,
 559                                          uint32_t requested_features)
 560 {
 561     return requested_features;
 562 }
 563
 564 static void virtio_scsi_reset(VirtIODevice *vdev)
 565 {
 566     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
 567
 568     s->resetting++;
 569     qbus_reset_all(&s->bus.qbus);
 570     s->resetting--;
 571
 572     s->sense_size = VIRTIO_SCSI_SENSE_SIZE;
 573     s->cdb_size = VIRTIO_SCSI_CDB_SIZE;
 574     s->events_dropped = false;
 575 }
 576
 577 /* The device does not have anything to save beyond the virtio data.
 578  * Request data is saved with callbacks from SCSI devices.
 579  */
 580 static void virtio_scsi_save(QEMUFile *f, void *opaque)
 581 {
 582     VirtIOSCSI *s = opaque;
 583     virtio_save(&s->vdev, f);
 584 }
 585
 586 static int virtio_scsi_load(QEMUFile *f, void *opaque, int version_id)
 587 {
 588     VirtIOSCSI *s = opaque;
 589     int ret;
 590
 591     ret = virtio_load(&s->vdev, f);
 592     if (ret) {
 593         return ret;
 594     }
 595     return 0;
 596 }
 597
 598 static void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev,
 599                                    uint32_t event, uint32_t reason)
 600 {
 601     VirtIOSCSIReq *req = virtio_scsi_pop_req(s, s->event_vq);
 602     VirtIOSCSIEvent *evt;
 603     int in_size;
 604
 605     if (!(s->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 606         return;
 607     }
 608
 609     if (!req) {
 610         s->events_dropped = true;
 611         return;
 612     }
 613
 614     if (req->elem.out_num || req->elem.in_num != 1) {
 615         virtio_scsi_bad_req();
 616     }
 617
 618     if (s->events_dropped) {
 619         event |= VIRTIO_SCSI_T_EVENTS_MISSED;
 620         s->events_dropped = false;
 621     }
 622
 623     in_size = req->elem.in_sg[0].iov_len;
 624     if (in_size < sizeof(VirtIOSCSIEvent)) {
 625         virtio_scsi_bad_req();
 626     }
 627
 628     evt = req->resp.event;
 629     memset(evt, 0, sizeof(VirtIOSCSIEvent));
 630     evt->event = event;
 631     evt->reason = reason;
 632     if (!dev) {
 633         assert(event == VIRTIO_SCSI_T_NO_EVENT);
 634     } else {
 635         evt->lun[0] = 1;
 636         evt->lun[1] = dev->id;
 637
 638         /* Linux wants us to keep the same encoding we use for REPORT LUNS.  */
 639         if (dev->lun >= 256) {
 640             evt->lun[2] = (dev->lun >> 8) | 0x40;
 641         }
 642         evt->lun[3] = dev->lun & 0xFF;
 643     }
 644     virtio_scsi_complete_req(req);
 645 }
 646
 647 static void virtio_scsi_handle_event(VirtIODevice *vdev, VirtQueue *vq)
 648 {
 649     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
 650
 651     if (s->events_dropped) {
 652         virtio_scsi_push_event(s, NULL, VIRTIO_SCSI_T_NO_EVENT, 0);
 653     }
 654 }
 655
 656 static void virtio_scsi_change(SCSIBus *bus, SCSIDevice *dev, SCSISense sense)
 657 {
 658     VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
 659
 660     if (((s->vdev.guest_features >> VIRTIO_SCSI_F_CHANGE) & 1) &&
 661         dev->type != TYPE_ROM) {
 662         virtio_scsi_push_event(s, dev, VIRTIO_SCSI_T_PARAM_CHANGE,
 663                                sense.asc | (sense.ascq << 8));
 664     }
 665 }
 666
 667 static void virtio_scsi_hotplug(SCSIBus *bus, SCSIDevice *dev)
 668 {
 669     VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
 670
 671     if ((s->vdev.guest_features >> VIRTIO_SCSI_F_HOTPLUG) & 1) {
 672         virtio_scsi_push_event(s, dev, VIRTIO_SCSI_T_TRANSPORT_RESET,
 673                                VIRTIO_SCSI_EVT_RESET_RESCAN);
 674     }
 675 }
 676
 677 static void virtio_scsi_hot_unplug(SCSIBus *bus, SCSIDevice *dev)
 678 {
 679     VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
 680
 681     if ((s->vdev.guest_features >> VIRTIO_SCSI_F_HOTPLUG) & 1) {
 682         virtio_scsi_push_event(s, dev, VIRTIO_SCSI_T_TRANSPORT_RESET,
 683                                VIRTIO_SCSI_EVT_RESET_REMOVED);
 684     }
 685 }
 686
 687 static struct SCSIBusInfo virtio_scsi_scsi_info = {
 688     .tcq = true,
 689     .max_channel = VIRTIO_SCSI_MAX_CHANNEL,
 690     .max_target = VIRTIO_SCSI_MAX_TARGET,
 691     .max_lun = VIRTIO_SCSI_MAX_LUN,
 692
 693     .complete = virtio_scsi_command_complete,
 694     .cancel = virtio_scsi_request_cancelled,
 695     .change = virtio_scsi_change,
 696     .hotplug = virtio_scsi_hotplug,
 697     .hot_unplug = virtio_scsi_hot_unplug,
 698     .get_sg_list = virtio_scsi_get_sg_list,
 699     .save_request = virtio_scsi_save_request,
 700     .load_request = virtio_scsi_load_request,
 701 };
 702
 703 VirtIODevice *virtio_scsi_init(DeviceState *dev, VirtIOSCSIConf *proxyconf)
 704 {
 705     VirtIOSCSI *s;
 706     static int virtio_scsi_id;
 707     size_t sz;
 708     int i;
 709
 710     sz = sizeof(VirtIOSCSI) + proxyconf->num_queues * sizeof(VirtQueue *);
 711     s = (VirtIOSCSI *)virtio_common_init("virtio-scsi", VIRTIO_ID_SCSI,
 712                                          sizeof(VirtIOSCSIConfig), sz);
 713
 714     s->qdev = dev;
 715     s->conf = proxyconf;
 716
 717     /* TODO set up vdev function pointers */
 718     s->vdev.get_config = virtio_scsi_get_config;
 719     s->vdev.set_config = virtio_scsi_set_config;
 720     s->vdev.get_features = virtio_scsi_get_features;
 721     s->vdev.reset = virtio_scsi_reset;
 722
 723     s->ctrl_vq = virtio_add_queue(&s->vdev, VIRTIO_SCSI_VQ_SIZE,
 724                                    virtio_scsi_handle_ctrl);
 725     s->event_vq = virtio_add_queue(&s->vdev, VIRTIO_SCSI_VQ_SIZE,
 726                                    virtio_scsi_handle_event);
 727     for (i = 0; i < s->conf->num_queues; i++) {
 728         s->cmd_vqs[i] = virtio_add_queue(&s->vdev, VIRTIO_SCSI_VQ_SIZE,
 729                                          virtio_scsi_handle_cmd);
 730     }
 731
 732     scsi_bus_new(&s->bus, dev, &virtio_scsi_scsi_info);
 733     if (!dev->hotplugged) {
 734         scsi_bus_legacy_handle_cmdline(&s->bus);
 735     }
 736
 737     register_savevm(dev, "virtio-scsi", virtio_scsi_id++, 1,
 738                     virtio_scsi_save, virtio_scsi_load, s);
 739
 740     return &s->vdev;
 741 }
 742
 743 void virtio_scsi_exit(VirtIODevice *vdev)
 744 {
 745     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
 746     unregister_savevm(s->qdev, "virtio-scsi", s);
 747     virtio_cleanup(vdev);
 748 }