drivers/scsi/virtio_scsi.c

   1 /*
   2  * Virtio SCSI HBA driver
   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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  17
  18 #include <linux/module.h>
  19 #include <linux/slab.h>
  20 #include <linux/mempool.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/virtio.h>
  23 #include <linux/virtio_ids.h>
  24 #include <linux/virtio_config.h>
  25 #include <linux/virtio_scsi.h>
  26 #include <linux/cpu.h>
  27 #include <linux/blkdev.h>
  28 #include <scsi/scsi_host.h>
  29 #include <scsi/scsi_device.h>
  30 #include <scsi/scsi_cmnd.h>
  31 #include <scsi/scsi_tcq.h>
  32 #include <scsi/scsi_devinfo.h>
  33 #include <linux/seqlock.h>
  34 #include <linux/blk-mq-virtio.h>
  35
  36 #define VIRTIO_SCSI_MEMPOOL_SZ 64
  37 #define VIRTIO_SCSI_EVENT_LEN 8
  38 #define VIRTIO_SCSI_VQ_BASE 2
  39
  40 /* Command queue element */
  41 struct virtio_scsi_cmd {
  42         struct scsi_cmnd *sc;
  43         struct completion *comp;
  44         union {
  45                 struct virtio_scsi_cmd_req       cmd;
  46                 struct virtio_scsi_cmd_req_pi    cmd_pi;
  47                 struct virtio_scsi_ctrl_tmf_req  tmf;
  48                 struct virtio_scsi_ctrl_an_req   an;
  49         } req;
  50         union {
  51                 struct virtio_scsi_cmd_resp      cmd;
  52                 struct virtio_scsi_ctrl_tmf_resp tmf;
  53                 struct virtio_scsi_ctrl_an_resp  an;
  54                 struct virtio_scsi_event         evt;
  55         } resp;
  56 } ____cacheline_aligned_in_smp;
  57
  58 struct virtio_scsi_event_node {
  59         struct virtio_scsi *vscsi;
  60         struct virtio_scsi_event event;
  61         struct work_struct work;
  62 };
  63
  64 struct virtio_scsi_vq {
  65         /* Protects vq */
  66         spinlock_t vq_lock;
  67
  68         struct virtqueue *vq;
  69 };
  70
  71 /* Driver instance state */
  72 struct virtio_scsi {
  73         struct virtio_device *vdev;
  74
  75         /* Get some buffers ready for event vq */
  76         struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN];
  77
  78         u32 num_queues;
  79
  80         /* If the affinity hint is set for virtqueues */
  81         bool affinity_hint_set;
  82
  83         struct hlist_node node;
  84
  85         /* Protected by event_vq lock */
  86         bool stop_events;
  87
  88         struct virtio_scsi_vq ctrl_vq;
  89         struct virtio_scsi_vq event_vq;
  90         struct virtio_scsi_vq req_vqs[];
  91 };
  92
  93 static struct kmem_cache *virtscsi_cmd_cache;
  94 static mempool_t *virtscsi_cmd_pool;
  95
  96 static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
  97 {
  98         return vdev->priv;
  99 }
 100
 101 static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
 102 {
 103         if (resid)
 104                 scsi_set_resid(sc, resid);
 105 }
 106
 107 /**
 108  * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
 109  *
 110  * Called with vq_lock held.
 111  */
 112 static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
 113 {
 114         struct virtio_scsi_cmd *cmd = buf;
 115         struct scsi_cmnd *sc = cmd->sc;
 116         struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
 117
 118         dev_dbg(&sc->device->sdev_gendev,
 119                 "cmd %p response %u status %#02x sense_len %u\n",
 120                 sc, resp->response, resp->status, resp->sense_len);
 121
 122         sc->result = resp->status;
 123         virtscsi_compute_resid(sc, virtio32_to_cpu(vscsi->vdev, resp->resid));
 124         switch (resp->response) {
 125         case VIRTIO_SCSI_S_OK:
 126                 set_host_byte(sc, DID_OK);
 127                 break;
 128         case VIRTIO_SCSI_S_OVERRUN:
 129                 set_host_byte(sc, DID_ERROR);
 130                 break;
 131         case VIRTIO_SCSI_S_ABORTED:
 132                 set_host_byte(sc, DID_ABORT);
 133                 break;
 134         case VIRTIO_SCSI_S_BAD_TARGET:
 135                 set_host_byte(sc, DID_BAD_TARGET);
 136                 break;
 137         case VIRTIO_SCSI_S_RESET:
 138                 set_host_byte(sc, DID_RESET);
 139                 break;
 140         case VIRTIO_SCSI_S_BUSY:
 141                 set_host_byte(sc, DID_BUS_BUSY);
 142                 break;
 143         case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
 144                 set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
 145                 break;
 146         case VIRTIO_SCSI_S_TARGET_FAILURE:
 147                 set_host_byte(sc, DID_TARGET_FAILURE);
 148                 break;
 149         case VIRTIO_SCSI_S_NEXUS_FAILURE:
 150                 set_host_byte(sc, DID_NEXUS_FAILURE);
 151                 break;
 152         default:
 153                 scmd_printk(KERN_WARNING, sc, "Unknown response %d",
 154                             resp->response);
 155                 /* fall through */
 156         case VIRTIO_SCSI_S_FAILURE:
 157                 set_host_byte(sc, DID_ERROR);
 158                 break;
 159         }
 160
 161         WARN_ON(virtio32_to_cpu(vscsi->vdev, resp->sense_len) >
 162                 VIRTIO_SCSI_SENSE_SIZE);
 163         if (sc->sense_buffer) {
 164                 memcpy(sc->sense_buffer, resp->sense,
 165                        min_t(u32,
 166                              virtio32_to_cpu(vscsi->vdev, resp->sense_len),
 167                              VIRTIO_SCSI_SENSE_SIZE));
 168                 if (resp->sense_len)
 169                         set_driver_byte(sc, DRIVER_SENSE);
 170         }
 171
 172         sc->scsi_done(sc);
 173 }
 174
 175 static void virtscsi_vq_done(struct virtio_scsi *vscsi,
 176                              struct virtio_scsi_vq *virtscsi_vq,
 177                              void (*fn)(struct virtio_scsi *vscsi, void *buf))
 178 {
 179         void *buf;
 180         unsigned int len;
 181         unsigned long flags;
 182         struct virtqueue *vq = virtscsi_vq->vq;
 183
 184         spin_lock_irqsave(&virtscsi_vq->vq_lock, flags);
 185         do {
 186                 virtqueue_disable_cb(vq);
 187                 while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
 188                         fn(vscsi, buf);
 189
 190                 if (unlikely(virtqueue_is_broken(vq)))
 191                         break;
 192         } while (!virtqueue_enable_cb(vq));
 193         spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
 194 }
 195
 196 static void virtscsi_req_done(struct virtqueue *vq)
 197 {
 198         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 199         struct virtio_scsi *vscsi = shost_priv(sh);
 200         int index = vq->index - VIRTIO_SCSI_VQ_BASE;
 201         struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index];
 202
 203         virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd);
 204 };
 205
 206 static void virtscsi_poll_requests(struct virtio_scsi *vscsi)
 207 {
 208         int i, num_vqs;
 209
 210         num_vqs = vscsi->num_queues;
 211         for (i = 0; i < num_vqs; i++)
 212                 virtscsi_vq_done(vscsi, &vscsi->req_vqs[i],
 213                                  virtscsi_complete_cmd);
 214 }
 215
 216 static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)
 217 {
 218         struct virtio_scsi_cmd *cmd = buf;
 219
 220         if (cmd->comp)
 221                 complete(cmd->comp);
 222 }
 223
 224 static void virtscsi_ctrl_done(struct virtqueue *vq)
 225 {
 226         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 227         struct virtio_scsi *vscsi = shost_priv(sh);
 228
 229         virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free);
 230 };
 231
 232 static void virtscsi_handle_event(struct work_struct *work);
 233
 234 static int virtscsi_kick_event(struct virtio_scsi *vscsi,
 235                                struct virtio_scsi_event_node *event_node)
 236 {
 237         int err;
 238         struct scatterlist sg;
 239         unsigned long flags;
 240
 241         INIT_WORK(&event_node->work, virtscsi_handle_event);
 242         sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
 243
 244         spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
 245
 246         err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node,
 247                                   GFP_ATOMIC);
 248         if (!err)
 249                 virtqueue_kick(vscsi->event_vq.vq);
 250
 251         spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
 252
 253         return err;
 254 }
 255
 256 static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
 257 {
 258         int i;
 259
 260         for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
 261                 vscsi->event_list[i].vscsi = vscsi;
 262                 virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
 263         }
 264
 265         return 0;
 266 }
 267
 268 static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
 269 {
 270         int i;
 271
 272         /* Stop scheduling work before calling cancel_work_sync.  */
 273         spin_lock_irq(&vscsi->event_vq.vq_lock);
 274         vscsi->stop_events = true;
 275         spin_unlock_irq(&vscsi->event_vq.vq_lock);
 276
 277         for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
 278                 cancel_work_sync(&vscsi->event_list[i].work);
 279 }
 280
 281 static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
 282                                             struct virtio_scsi_event *event)
 283 {
 284         struct scsi_device *sdev;
 285         struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 286         unsigned int target = event->lun[1];
 287         unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 288
 289         switch (virtio32_to_cpu(vscsi->vdev, event->reason)) {
 290         case VIRTIO_SCSI_EVT_RESET_RESCAN:
 291                 scsi_add_device(shost, 0, target, lun);
 292                 break;
 293         case VIRTIO_SCSI_EVT_RESET_REMOVED:
 294                 sdev = scsi_device_lookup(shost, 0, target, lun);
 295                 if (sdev) {
 296                         scsi_remove_device(sdev);
 297                         scsi_device_put(sdev);
 298                 } else {
 299                         pr_err("SCSI device %d 0 %d %d not found\n",
 300                                 shost->host_no, target, lun);
 301                 }
 302                 break;
 303         default:
 304                 pr_info("Unsupport virtio scsi event reason %x\n", event->reason);
 305         }
 306 }
 307
 308 static void virtscsi_handle_param_change(struct virtio_scsi *vscsi,
 309                                          struct virtio_scsi_event *event)
 310 {
 311         struct scsi_device *sdev;
 312         struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 313         unsigned int target = event->lun[1];
 314         unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 315         u8 asc = virtio32_to_cpu(vscsi->vdev, event->reason) & 255;
 316         u8 ascq = virtio32_to_cpu(vscsi->vdev, event->reason) >> 8;
 317
 318         sdev = scsi_device_lookup(shost, 0, target, lun);
 319         if (!sdev) {
 320                 pr_err("SCSI device %d 0 %d %d not found\n",
 321                         shost->host_no, target, lun);
 322                 return;
 323         }
 324
 325         /* Handle "Parameters changed", "Mode parameters changed", and
 326            "Capacity data has changed".  */
 327         if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
 328                 scsi_rescan_device(&sdev->sdev_gendev);
 329
 330         scsi_device_put(sdev);
 331 }
 332
 333 static void virtscsi_handle_event(struct work_struct *work)
 334 {
 335         struct virtio_scsi_event_node *event_node =
 336                 container_of(work, struct virtio_scsi_event_node, work);
 337         struct virtio_scsi *vscsi = event_node->vscsi;
 338         struct virtio_scsi_event *event = &event_node->event;
 339
 340         if (event->event &
 341             cpu_to_virtio32(vscsi->vdev, VIRTIO_SCSI_T_EVENTS_MISSED)) {
 342                 event->event &= ~cpu_to_virtio32(vscsi->vdev,
 343                                                    VIRTIO_SCSI_T_EVENTS_MISSED);
 344                 scsi_scan_host(virtio_scsi_host(vscsi->vdev));
 345         }
 346
 347         switch (virtio32_to_cpu(vscsi->vdev, event->event)) {
 348         case VIRTIO_SCSI_T_NO_EVENT:
 349                 break;
 350         case VIRTIO_SCSI_T_TRANSPORT_RESET:
 351                 virtscsi_handle_transport_reset(vscsi, event);
 352                 break;
 353         case VIRTIO_SCSI_T_PARAM_CHANGE:
 354                 virtscsi_handle_param_change(vscsi, event);
 355                 break;
 356         default:
 357                 pr_err("Unsupport virtio scsi event %x\n", event->event);
 358         }
 359         virtscsi_kick_event(vscsi, event_node);
 360 }
 361
 362 static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf)
 363 {
 364         struct virtio_scsi_event_node *event_node = buf;
 365
 366         if (!vscsi->stop_events)
 367                 queue_work(system_freezable_wq, &event_node->work);
 368 }
 369
 370 static void virtscsi_event_done(struct virtqueue *vq)
 371 {
 372         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 373         struct virtio_scsi *vscsi = shost_priv(sh);
 374
 375         virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event);
 376 };
 377
 378 /**
 379  * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue
 380  * @vq          : the struct virtqueue we're talking about
 381  * @cmd         : command structure
 382  * @req_size    : size of the request buffer
 383  * @resp_size   : size of the response buffer
 384  */
 385 static int virtscsi_add_cmd(struct virtqueue *vq,
 386                             struct virtio_scsi_cmd *cmd,
 387                             size_t req_size, size_t resp_size)
 388 {
 389         struct scsi_cmnd *sc = cmd->sc;
 390         struct scatterlist *sgs[6], req, resp;
 391         struct sg_table *out, *in;
 392         unsigned out_num = 0, in_num = 0;
 393
 394         out = in = NULL;
 395
 396         if (sc && sc->sc_data_direction != DMA_NONE) {
 397                 if (sc->sc_data_direction != DMA_FROM_DEVICE)
 398                         out = &sc->sdb.table;
 399                 if (sc->sc_data_direction != DMA_TO_DEVICE)
 400                         in = &sc->sdb.table;
 401         }
 402
 403         /* Request header.  */
 404         sg_init_one(&req, &cmd->req, req_size);
 405         sgs[out_num++] = &req;
 406
 407         /* Data-out buffer.  */
 408         if (out) {
 409                 /* Place WRITE protection SGLs before Data OUT payload */
 410                 if (scsi_prot_sg_count(sc))
 411                         sgs[out_num++] = scsi_prot_sglist(sc);
 412                 sgs[out_num++] = out->sgl;
 413         }
 414
 415         /* Response header.  */
 416         sg_init_one(&resp, &cmd->resp, resp_size);
 417         sgs[out_num + in_num++] = &resp;
 418
 419         /* Data-in buffer */
 420         if (in) {
 421                 /* Place READ protection SGLs before Data IN payload */
 422                 if (scsi_prot_sg_count(sc))
 423                         sgs[out_num + in_num++] = scsi_prot_sglist(sc);
 424                 sgs[out_num + in_num++] = in->sgl;
 425         }
 426
 427         return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC);
 428 }
 429
 430 static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq,
 431                              struct virtio_scsi_cmd *cmd,
 432                              size_t req_size, size_t resp_size)
 433 {
 434         unsigned long flags;
 435         int err;
 436         bool needs_kick = false;
 437
 438         spin_lock_irqsave(&vq->vq_lock, flags);
 439         err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size);
 440         if (!err)
 441                 needs_kick = virtqueue_kick_prepare(vq->vq);
 442
 443         spin_unlock_irqrestore(&vq->vq_lock, flags);
 444
 445         if (needs_kick)
 446                 virtqueue_notify(vq->vq);
 447         return err;
 448 }
 449
 450 static void virtio_scsi_init_hdr(struct virtio_device *vdev,
 451                                  struct virtio_scsi_cmd_req *cmd,
 452                                  struct scsi_cmnd *sc)
 453 {
 454         cmd->lun[0] = 1;
 455         cmd->lun[1] = sc->device->id;
 456         cmd->lun[2] = (sc->device->lun >> 8) | 0x40;
 457         cmd->lun[3] = sc->device->lun & 0xff;
 458         cmd->tag = cpu_to_virtio64(vdev, (unsigned long)sc);
 459         cmd->task_attr = VIRTIO_SCSI_S_SIMPLE;
 460         cmd->prio = 0;
 461         cmd->crn = 0;
 462 }
 463
 464 #ifdef CONFIG_BLK_DEV_INTEGRITY
 465 static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev,
 466                                     struct virtio_scsi_cmd_req_pi *cmd_pi,
 467                                     struct scsi_cmnd *sc)
 468 {
 469         struct request *rq = sc->request;
 470         struct blk_integrity *bi;
 471
 472         virtio_scsi_init_hdr(vdev, (struct virtio_scsi_cmd_req *)cmd_pi, sc);
 473
 474         if (!rq || !scsi_prot_sg_count(sc))
 475                 return;
 476
 477         bi = blk_get_integrity(rq->rq_disk);
 478
 479         if (sc->sc_data_direction == DMA_TO_DEVICE)
 480                 cmd_pi->pi_bytesout = cpu_to_virtio32(vdev,
 481                                                       bio_integrity_bytes(bi,
 482                                                         blk_rq_sectors(rq)));
 483         else if (sc->sc_data_direction == DMA_FROM_DEVICE)
 484                 cmd_pi->pi_bytesin = cpu_to_virtio32(vdev,
 485                                                      bio_integrity_bytes(bi,
 486                                                         blk_rq_sectors(rq)));
 487 }
 488 #endif
 489
 490 static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi,
 491                                                   struct scsi_cmnd *sc)
 492 {
 493         u32 tag = blk_mq_unique_tag(sc->request);
 494         u16 hwq = blk_mq_unique_tag_to_hwq(tag);
 495
 496         return &vscsi->req_vqs[hwq];
 497 }
 498
 499 static int virtscsi_queuecommand(struct Scsi_Host *shost,
 500                                  struct scsi_cmnd *sc)
 501 {
 502         struct virtio_scsi *vscsi = shost_priv(shost);
 503         struct virtio_scsi_vq *req_vq = virtscsi_pick_vq_mq(vscsi, sc);
 504         struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
 505         unsigned long flags;
 506         int req_size;
 507         int ret;
 508
 509         BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
 510
 511         /* TODO: check feature bit and fail if unsupported?  */
 512         BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
 513
 514         dev_dbg(&sc->device->sdev_gendev,
 515                 "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
 516
 517         cmd->sc = sc;
 518
 519         BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
 520
 521 #ifdef CONFIG_BLK_DEV_INTEGRITY
 522         if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) {
 523                 virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, sc);
 524                 memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len);
 525                 req_size = sizeof(cmd->req.cmd_pi);
 526         } else
 527 #endif
 528         {
 529                 virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, sc);
 530                 memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
 531                 req_size = sizeof(cmd->req.cmd);
 532         }
 533
 534         ret = virtscsi_kick_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd));
 535         if (ret == -EIO) {
 536                 cmd->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
 537                 spin_lock_irqsave(&req_vq->vq_lock, flags);
 538                 virtscsi_complete_cmd(vscsi, cmd);
 539                 spin_unlock_irqrestore(&req_vq->vq_lock, flags);
 540         } else if (ret != 0) {
 541                 return SCSI_MLQUEUE_HOST_BUSY;
 542         }
 543         return 0;
 544 }
 545
 546 static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
 547 {
 548         DECLARE_COMPLETION_ONSTACK(comp);
 549         int ret = FAILED;
 550
 551         cmd->comp = &comp;
 552         if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd,
 553                               sizeof cmd->req.tmf, sizeof cmd->resp.tmf) < 0)
 554                 goto out;
 555
 556         wait_for_completion(&comp);
 557         if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
 558             cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
 559                 ret = SUCCESS;
 560
 561         /*
 562          * The spec guarantees that all requests related to the TMF have
 563          * been completed, but the callback might not have run yet if
 564          * we're using independent interrupts (e.g. MSI).  Poll the
 565          * virtqueues once.
 566          *
 567          * In the abort case, sc->scsi_done will do nothing, because
 568          * the block layer must have detected a timeout and as a result
 569          * REQ_ATOM_COMPLETE has been set.
 570          */
 571         virtscsi_poll_requests(vscsi);
 572
 573 out:
 574         mempool_free(cmd, virtscsi_cmd_pool);
 575         return ret;
 576 }
 577
 578 static int virtscsi_device_reset(struct scsi_cmnd *sc)
 579 {
 580         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 581         struct virtio_scsi_cmd *cmd;
 582
 583         sdev_printk(KERN_INFO, sc->device, "device reset\n");
 584         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 585         if (!cmd)
 586                 return FAILED;
 587
 588         memset(cmd, 0, sizeof(*cmd));
 589         cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 590                 .type = VIRTIO_SCSI_T_TMF,
 591                 .subtype = cpu_to_virtio32(vscsi->vdev,
 592                                              VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET),
 593                 .lun[0] = 1,
 594                 .lun[1] = sc->device->id,
 595                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 596                 .lun[3] = sc->device->lun & 0xff,
 597         };
 598         return virtscsi_tmf(vscsi, cmd);
 599 }
 600
 601 static int virtscsi_device_alloc(struct scsi_device *sdevice)
 602 {
 603         /*
 604          * Passed through SCSI targets (e.g. with qemu's 'scsi-block')
 605          * may have transfer limits which come from the host SCSI
 606          * controller or something on the host side other than the
 607          * target itself.
 608          *
 609          * To make this work properly, the hypervisor can adjust the
 610          * target's VPD information to advertise these limits.  But
 611          * for that to work, the guest has to look at the VPD pages,
 612          * which we won't do by default if it is an SPC-2 device, even
 613          * if it does actually support it.
 614          *
 615          * So, set the blist to always try to read the VPD pages.
 616          */
 617         sdevice->sdev_bflags = BLIST_TRY_VPD_PAGES;
 618
 619         return 0;
 620 }
 621
 622
 623 /**
 624  * virtscsi_change_queue_depth() - Change a virtscsi target's queue depth
 625  * @sdev:       Virtscsi target whose queue depth to change
 626  * @qdepth:     New queue depth
 627  */
 628 static int virtscsi_change_queue_depth(struct scsi_device *sdev, int qdepth)
 629 {
 630         struct Scsi_Host *shost = sdev->host;
 631         int max_depth = shost->cmd_per_lun;
 632
 633         return scsi_change_queue_depth(sdev, min(max_depth, qdepth));
 634 }
 635
 636 static int virtscsi_abort(struct scsi_cmnd *sc)
 637 {
 638         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 639         struct virtio_scsi_cmd *cmd;
 640
 641         scmd_printk(KERN_INFO, sc, "abort\n");
 642         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 643         if (!cmd)
 644                 return FAILED;
 645
 646         memset(cmd, 0, sizeof(*cmd));
 647         cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 648                 .type = VIRTIO_SCSI_T_TMF,
 649                 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
 650                 .lun[0] = 1,
 651                 .lun[1] = sc->device->id,
 652                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 653                 .lun[3] = sc->device->lun & 0xff,
 654                 .tag = cpu_to_virtio64(vscsi->vdev, (unsigned long)sc),
 655         };
 656         return virtscsi_tmf(vscsi, cmd);
 657 }
 658
 659 static int virtscsi_map_queues(struct Scsi_Host *shost)
 660 {
 661         struct virtio_scsi *vscsi = shost_priv(shost);
 662         struct blk_mq_queue_map *qmap = &shost->tag_set.map[0];
 663
 664         return blk_mq_virtio_map_queues(qmap, vscsi->vdev, 2);
 665 }
 666
 667 /*
 668  * The host guarantees to respond to each command, although I/O
 669  * latencies might be higher than on bare metal.  Reset the timer
 670  * unconditionally to give the host a chance to perform EH.
 671  */
 672 static enum blk_eh_timer_return virtscsi_eh_timed_out(struct scsi_cmnd *scmnd)
 673 {
 674         return BLK_EH_RESET_TIMER;
 675 }
 676
 677 static struct scsi_host_template virtscsi_host_template = {
 678         .module = THIS_MODULE,
 679         .name = "Virtio SCSI HBA",
 680         .proc_name = "virtio_scsi",
 681         .this_id = -1,
 682         .cmd_size = sizeof(struct virtio_scsi_cmd),
 683         .queuecommand = virtscsi_queuecommand,
 684         .change_queue_depth = virtscsi_change_queue_depth,
 685         .eh_abort_handler = virtscsi_abort,
 686         .eh_device_reset_handler = virtscsi_device_reset,
 687         .eh_timed_out = virtscsi_eh_timed_out,
 688         .slave_alloc = virtscsi_device_alloc,
 689
 690         .dma_boundary = UINT_MAX,
 691         .map_queues = virtscsi_map_queues,
 692         .track_queue_depth = 1,
 693         .force_blk_mq = 1,
 694 };
 695
 696 #define virtscsi_config_get(vdev, fld) \
 697         ({ \
 698                 typeof(((struct virtio_scsi_config *)0)->fld) __val; \
 699                 virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \
 700                 __val; \
 701         })
 702
 703 #define virtscsi_config_set(vdev, fld, val) \
 704         do { \
 705                 typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
 706                 virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \
 707         } while(0)
 708
 709 static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
 710                              struct virtqueue *vq)
 711 {
 712         spin_lock_init(&virtscsi_vq->vq_lock);
 713         virtscsi_vq->vq = vq;
 714 }
 715
 716 static void virtscsi_remove_vqs(struct virtio_device *vdev)
 717 {
 718         /* Stop all the virtqueues. */
 719         vdev->config->reset(vdev);
 720         vdev->config->del_vqs(vdev);
 721 }
 722
 723 static int virtscsi_init(struct virtio_device *vdev,
 724                          struct virtio_scsi *vscsi)
 725 {
 726         int err;
 727         u32 i;
 728         u32 num_vqs;
 729         vq_callback_t **callbacks;
 730         const char **names;
 731         struct virtqueue **vqs;
 732         struct irq_affinity desc = { .pre_vectors = 2 };
 733
 734         num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;
 735         vqs = kmalloc_array(num_vqs, sizeof(struct virtqueue *), GFP_KERNEL);
 736         callbacks = kmalloc_array(num_vqs, sizeof(vq_callback_t *),
 737                                   GFP_KERNEL);
 738         names = kmalloc_array(num_vqs, sizeof(char *), GFP_KERNEL);
 739
 740         if (!callbacks || !vqs || !names) {
 741                 err = -ENOMEM;
 742                 goto out;
 743         }
 744
 745         callbacks[0] = virtscsi_ctrl_done;
 746         callbacks[1] = virtscsi_event_done;
 747         names[0] = "control";
 748         names[1] = "event";
 749         for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) {
 750                 callbacks[i] = virtscsi_req_done;
 751                 names[i] = "request";
 752         }
 753
 754         /* Discover virtqueues and write information to configuration.  */
 755         err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc);
 756         if (err)
 757                 goto out;
 758
 759         virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
 760         virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
 761         for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
 762                 virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
 763                                  vqs[i]);
 764
 765         virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
 766         virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
 767
 768         err = 0;
 769
 770 out:
 771         kfree(names);
 772         kfree(callbacks);
 773         kfree(vqs);
 774         if (err)
 775                 virtscsi_remove_vqs(vdev);
 776         return err;
 777 }
 778
 779 static int virtscsi_probe(struct virtio_device *vdev)
 780 {
 781         struct Scsi_Host *shost;
 782         struct virtio_scsi *vscsi;
 783         int err;
 784         u32 sg_elems, num_targets;
 785         u32 cmd_per_lun;
 786         u32 num_queues;
 787
 788         if (!vdev->config->get) {
 789                 dev_err(&vdev->dev, "%s failure: config access disabled\n",
 790                         __func__);
 791                 return -EINVAL;
 792         }
 793
 794         /* We need to know how many queues before we allocate. */
 795         num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
 796         num_queues = min_t(unsigned int, nr_cpu_ids, num_queues);
 797
 798         num_targets = virtscsi_config_get(vdev, max_target) + 1;
 799
 800         shost = scsi_host_alloc(&virtscsi_host_template,
 801                 sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues);
 802         if (!shost)
 803                 return -ENOMEM;
 804
 805         sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
 806         shost->sg_tablesize = sg_elems;
 807         vscsi = shost_priv(shost);
 808         vscsi->vdev = vdev;
 809         vscsi->num_queues = num_queues;
 810         vdev->priv = shost;
 811
 812         err = virtscsi_init(vdev, vscsi);
 813         if (err)
 814                 goto virtscsi_init_failed;
 815
 816         shost->can_queue = virtqueue_get_vring_size(vscsi->req_vqs[0].vq);
 817
 818         cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
 819         shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
 820         shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
 821
 822         /* LUNs > 256 are reported with format 1, so they go in the range
 823          * 16640-32767.
 824          */
 825         shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
 826         shost->max_id = num_targets;
 827         shost->max_channel = 0;
 828         shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
 829         shost->nr_hw_queues = num_queues;
 830
 831 #ifdef CONFIG_BLK_DEV_INTEGRITY
 832         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
 833                 int host_prot;
 834
 835                 host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
 836                             SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
 837                             SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
 838
 839                 scsi_host_set_prot(shost, host_prot);
 840                 scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC);
 841         }
 842 #endif
 843
 844         err = scsi_add_host(shost, &vdev->dev);
 845         if (err)
 846                 goto scsi_add_host_failed;
 847
 848         virtio_device_ready(vdev);
 849
 850         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 851                 virtscsi_kick_event_all(vscsi);
 852
 853         scsi_scan_host(shost);
 854         return 0;
 855
 856 scsi_add_host_failed:
 857         vdev->config->del_vqs(vdev);
 858 virtscsi_init_failed:
 859         scsi_host_put(shost);
 860         return err;
 861 }
 862
 863 static void virtscsi_remove(struct virtio_device *vdev)
 864 {
 865         struct Scsi_Host *shost = virtio_scsi_host(vdev);
 866         struct virtio_scsi *vscsi = shost_priv(shost);
 867
 868         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 869                 virtscsi_cancel_event_work(vscsi);
 870
 871         scsi_remove_host(shost);
 872         virtscsi_remove_vqs(vdev);
 873         scsi_host_put(shost);
 874 }
 875
 876 #ifdef CONFIG_PM_SLEEP
 877 static int virtscsi_freeze(struct virtio_device *vdev)
 878 {
 879         virtscsi_remove_vqs(vdev);
 880         return 0;
 881 }
 882
 883 static int virtscsi_restore(struct virtio_device *vdev)
 884 {
 885         struct Scsi_Host *sh = virtio_scsi_host(vdev);
 886         struct virtio_scsi *vscsi = shost_priv(sh);
 887         int err;
 888
 889         err = virtscsi_init(vdev, vscsi);
 890         if (err)
 891                 return err;
 892
 893         virtio_device_ready(vdev);
 894
 895         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 896                 virtscsi_kick_event_all(vscsi);
 897
 898         return err;
 899 }
 900 #endif
 901
 902 static struct virtio_device_id id_table[] = {
 903         { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
 904         { 0 },
 905 };
 906
 907 static unsigned int features[] = {
 908         VIRTIO_SCSI_F_HOTPLUG,
 909         VIRTIO_SCSI_F_CHANGE,
 910 #ifdef CONFIG_BLK_DEV_INTEGRITY
 911         VIRTIO_SCSI_F_T10_PI,
 912 #endif
 913 };
 914
 915 static struct virtio_driver virtio_scsi_driver = {
 916         .feature_table = features,
 917         .feature_table_size = ARRAY_SIZE(features),
 918         .driver.name = KBUILD_MODNAME,
 919         .driver.owner = THIS_MODULE,
 920         .id_table = id_table,
 921         .probe = virtscsi_probe,
 922 #ifdef CONFIG_PM_SLEEP
 923         .freeze = virtscsi_freeze,
 924         .restore = virtscsi_restore,
 925 #endif
 926         .remove = virtscsi_remove,
 927 };
 928
 929 static int __init init(void)
 930 {
 931         int ret = -ENOMEM;
 932
 933         virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
 934         if (!virtscsi_cmd_cache) {
 935                 pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
 936                 goto error;
 937         }
 938
 939
 940         virtscsi_cmd_pool =
 941                 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
 942                                          virtscsi_cmd_cache);
 943         if (!virtscsi_cmd_pool) {
 944                 pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
 945                 goto error;
 946         }
 947         ret = register_virtio_driver(&virtio_scsi_driver);
 948         if (ret < 0)
 949                 goto error;
 950
 951         return 0;
 952
 953 error:
 954         if (virtscsi_cmd_pool) {
 955                 mempool_destroy(virtscsi_cmd_pool);
 956                 virtscsi_cmd_pool = NULL;
 957         }
 958         if (virtscsi_cmd_cache) {
 959                 kmem_cache_destroy(virtscsi_cmd_cache);
 960                 virtscsi_cmd_cache = NULL;
 961         }
 962         return ret;
 963 }
 964
 965 static void __exit fini(void)
 966 {
 967         unregister_virtio_driver(&virtio_scsi_driver);
 968         mempool_destroy(virtscsi_cmd_pool);
 969         kmem_cache_destroy(virtscsi_cmd_cache);
 970 }
 971 module_init(init);
 972 module_exit(fini);
 973
 974 MODULE_DEVICE_TABLE(virtio, id_table);
 975 MODULE_DESCRIPTION("Virtio SCSI HBA driver");
 976 MODULE_LICENSE("GPL");