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                 return;
 105
 106         if (!scsi_bidi_cmnd(sc)) {
 107                 scsi_set_resid(sc, resid);
 108                 return;
 109         }
 110
 111         scsi_in(sc)->resid = min(resid, scsi_in(sc)->length);
 112         scsi_out(sc)->resid = resid - scsi_in(sc)->resid;
 113 }
 114
 115 /**
 116  * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
 117  *
 118  * Called with vq_lock held.
 119  */
 120 static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
 121 {
 122         struct virtio_scsi_cmd *cmd = buf;
 123         struct scsi_cmnd *sc = cmd->sc;
 124         struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
 125
 126         dev_dbg(&sc->device->sdev_gendev,
 127                 "cmd %p response %u status %#02x sense_len %u\n",
 128                 sc, resp->response, resp->status, resp->sense_len);
 129
 130         sc->result = resp->status;
 131         virtscsi_compute_resid(sc, virtio32_to_cpu(vscsi->vdev, resp->resid));
 132         switch (resp->response) {
 133         case VIRTIO_SCSI_S_OK:
 134                 set_host_byte(sc, DID_OK);
 135                 break;
 136         case VIRTIO_SCSI_S_OVERRUN:
 137                 set_host_byte(sc, DID_ERROR);
 138                 break;
 139         case VIRTIO_SCSI_S_ABORTED:
 140                 set_host_byte(sc, DID_ABORT);
 141                 break;
 142         case VIRTIO_SCSI_S_BAD_TARGET:
 143                 set_host_byte(sc, DID_BAD_TARGET);
 144                 break;
 145         case VIRTIO_SCSI_S_RESET:
 146                 set_host_byte(sc, DID_RESET);
 147                 break;
 148         case VIRTIO_SCSI_S_BUSY:
 149                 set_host_byte(sc, DID_BUS_BUSY);
 150                 break;
 151         case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
 152                 set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
 153                 break;
 154         case VIRTIO_SCSI_S_TARGET_FAILURE:
 155                 set_host_byte(sc, DID_TARGET_FAILURE);
 156                 break;
 157         case VIRTIO_SCSI_S_NEXUS_FAILURE:
 158                 set_host_byte(sc, DID_NEXUS_FAILURE);
 159                 break;
 160         default:
 161                 scmd_printk(KERN_WARNING, sc, "Unknown response %d",
 162                             resp->response);
 163                 /* fall through */
 164         case VIRTIO_SCSI_S_FAILURE:
 165                 set_host_byte(sc, DID_ERROR);
 166                 break;
 167         }
 168
 169         WARN_ON(virtio32_to_cpu(vscsi->vdev, resp->sense_len) >
 170                 VIRTIO_SCSI_SENSE_SIZE);
 171         if (sc->sense_buffer) {
 172                 memcpy(sc->sense_buffer, resp->sense,
 173                        min_t(u32,
 174                              virtio32_to_cpu(vscsi->vdev, resp->sense_len),
 175                              VIRTIO_SCSI_SENSE_SIZE));
 176                 if (resp->sense_len)
 177                         set_driver_byte(sc, DRIVER_SENSE);
 178         }
 179
 180         sc->scsi_done(sc);
 181 }
 182
 183 static void virtscsi_vq_done(struct virtio_scsi *vscsi,
 184                              struct virtio_scsi_vq *virtscsi_vq,
 185                              void (*fn)(struct virtio_scsi *vscsi, void *buf))
 186 {
 187         void *buf;
 188         unsigned int len;
 189         unsigned long flags;
 190         struct virtqueue *vq = virtscsi_vq->vq;
 191
 192         spin_lock_irqsave(&virtscsi_vq->vq_lock, flags);
 193         do {
 194                 virtqueue_disable_cb(vq);
 195                 while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
 196                         fn(vscsi, buf);
 197
 198                 if (unlikely(virtqueue_is_broken(vq)))
 199                         break;
 200         } while (!virtqueue_enable_cb(vq));
 201         spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
 202 }
 203
 204 static void virtscsi_req_done(struct virtqueue *vq)
 205 {
 206         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 207         struct virtio_scsi *vscsi = shost_priv(sh);
 208         int index = vq->index - VIRTIO_SCSI_VQ_BASE;
 209         struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index];
 210
 211         virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd);
 212 };
 213
 214 static void virtscsi_poll_requests(struct virtio_scsi *vscsi)
 215 {
 216         int i, num_vqs;
 217
 218         num_vqs = vscsi->num_queues;
 219         for (i = 0; i < num_vqs; i++)
 220                 virtscsi_vq_done(vscsi, &vscsi->req_vqs[i],
 221                                  virtscsi_complete_cmd);
 222 }
 223
 224 static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)
 225 {
 226         struct virtio_scsi_cmd *cmd = buf;
 227
 228         if (cmd->comp)
 229                 complete(cmd->comp);
 230 }
 231
 232 static void virtscsi_ctrl_done(struct virtqueue *vq)
 233 {
 234         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 235         struct virtio_scsi *vscsi = shost_priv(sh);
 236
 237         virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free);
 238 };
 239
 240 static void virtscsi_handle_event(struct work_struct *work);
 241
 242 static int virtscsi_kick_event(struct virtio_scsi *vscsi,
 243                                struct virtio_scsi_event_node *event_node)
 244 {
 245         int err;
 246         struct scatterlist sg;
 247         unsigned long flags;
 248
 249         INIT_WORK(&event_node->work, virtscsi_handle_event);
 250         sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
 251
 252         spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
 253
 254         err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node,
 255                                   GFP_ATOMIC);
 256         if (!err)
 257                 virtqueue_kick(vscsi->event_vq.vq);
 258
 259         spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
 260
 261         return err;
 262 }
 263
 264 static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
 265 {
 266         int i;
 267
 268         for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
 269                 vscsi->event_list[i].vscsi = vscsi;
 270                 virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
 271         }
 272
 273         return 0;
 274 }
 275
 276 static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
 277 {
 278         int i;
 279
 280         /* Stop scheduling work before calling cancel_work_sync.  */
 281         spin_lock_irq(&vscsi->event_vq.vq_lock);
 282         vscsi->stop_events = true;
 283         spin_unlock_irq(&vscsi->event_vq.vq_lock);
 284
 285         for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
 286                 cancel_work_sync(&vscsi->event_list[i].work);
 287 }
 288
 289 static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
 290                                             struct virtio_scsi_event *event)
 291 {
 292         struct scsi_device *sdev;
 293         struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 294         unsigned int target = event->lun[1];
 295         unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 296
 297         switch (virtio32_to_cpu(vscsi->vdev, event->reason)) {
 298         case VIRTIO_SCSI_EVT_RESET_RESCAN:
 299                 scsi_add_device(shost, 0, target, lun);
 300                 break;
 301         case VIRTIO_SCSI_EVT_RESET_REMOVED:
 302                 sdev = scsi_device_lookup(shost, 0, target, lun);
 303                 if (sdev) {
 304                         scsi_remove_device(sdev);
 305                         scsi_device_put(sdev);
 306                 } else {
 307                         pr_err("SCSI device %d 0 %d %d not found\n",
 308                                 shost->host_no, target, lun);
 309                 }
 310                 break;
 311         default:
 312                 pr_info("Unsupport virtio scsi event reason %x\n", event->reason);
 313         }
 314 }
 315
 316 static void virtscsi_handle_param_change(struct virtio_scsi *vscsi,
 317                                          struct virtio_scsi_event *event)
 318 {
 319         struct scsi_device *sdev;
 320         struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 321         unsigned int target = event->lun[1];
 322         unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 323         u8 asc = virtio32_to_cpu(vscsi->vdev, event->reason) & 255;
 324         u8 ascq = virtio32_to_cpu(vscsi->vdev, event->reason) >> 8;
 325
 326         sdev = scsi_device_lookup(shost, 0, target, lun);
 327         if (!sdev) {
 328                 pr_err("SCSI device %d 0 %d %d not found\n",
 329                         shost->host_no, target, lun);
 330                 return;
 331         }
 332
 333         /* Handle "Parameters changed", "Mode parameters changed", and
 334            "Capacity data has changed".  */
 335         if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
 336                 scsi_rescan_device(&sdev->sdev_gendev);
 337
 338         scsi_device_put(sdev);
 339 }
 340
 341 static void virtscsi_handle_event(struct work_struct *work)
 342 {
 343         struct virtio_scsi_event_node *event_node =
 344                 container_of(work, struct virtio_scsi_event_node, work);
 345         struct virtio_scsi *vscsi = event_node->vscsi;
 346         struct virtio_scsi_event *event = &event_node->event;
 347
 348         if (event->event &
 349             cpu_to_virtio32(vscsi->vdev, VIRTIO_SCSI_T_EVENTS_MISSED)) {
 350                 event->event &= ~cpu_to_virtio32(vscsi->vdev,
 351                                                    VIRTIO_SCSI_T_EVENTS_MISSED);
 352                 scsi_scan_host(virtio_scsi_host(vscsi->vdev));
 353         }
 354
 355         switch (virtio32_to_cpu(vscsi->vdev, event->event)) {
 356         case VIRTIO_SCSI_T_NO_EVENT:
 357                 break;
 358         case VIRTIO_SCSI_T_TRANSPORT_RESET:
 359                 virtscsi_handle_transport_reset(vscsi, event);
 360                 break;
 361         case VIRTIO_SCSI_T_PARAM_CHANGE:
 362                 virtscsi_handle_param_change(vscsi, event);
 363                 break;
 364         default:
 365                 pr_err("Unsupport virtio scsi event %x\n", event->event);
 366         }
 367         virtscsi_kick_event(vscsi, event_node);
 368 }
 369
 370 static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf)
 371 {
 372         struct virtio_scsi_event_node *event_node = buf;
 373
 374         if (!vscsi->stop_events)
 375                 queue_work(system_freezable_wq, &event_node->work);
 376 }
 377
 378 static void virtscsi_event_done(struct virtqueue *vq)
 379 {
 380         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 381         struct virtio_scsi *vscsi = shost_priv(sh);
 382
 383         virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event);
 384 };
 385
 386 /**
 387  * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue
 388  * @vq          : the struct virtqueue we're talking about
 389  * @cmd         : command structure
 390  * @req_size    : size of the request buffer
 391  * @resp_size   : size of the response buffer
 392  */
 393 static int virtscsi_add_cmd(struct virtqueue *vq,
 394                             struct virtio_scsi_cmd *cmd,
 395                             size_t req_size, size_t resp_size)
 396 {
 397         struct scsi_cmnd *sc = cmd->sc;
 398         struct scatterlist *sgs[6], req, resp;
 399         struct sg_table *out, *in;
 400         unsigned out_num = 0, in_num = 0;
 401
 402         out = in = NULL;
 403
 404         if (sc && sc->sc_data_direction != DMA_NONE) {
 405                 if (sc->sc_data_direction != DMA_FROM_DEVICE)
 406                         out = &scsi_out(sc)->table;
 407                 if (sc->sc_data_direction != DMA_TO_DEVICE)
 408                         in = &scsi_in(sc)->table;
 409         }
 410
 411         /* Request header.  */
 412         sg_init_one(&req, &cmd->req, req_size);
 413         sgs[out_num++] = &req;
 414
 415         /* Data-out buffer.  */
 416         if (out) {
 417                 /* Place WRITE protection SGLs before Data OUT payload */
 418                 if (scsi_prot_sg_count(sc))
 419                         sgs[out_num++] = scsi_prot_sglist(sc);
 420                 sgs[out_num++] = out->sgl;
 421         }
 422
 423         /* Response header.  */
 424         sg_init_one(&resp, &cmd->resp, resp_size);
 425         sgs[out_num + in_num++] = &resp;
 426
 427         /* Data-in buffer */
 428         if (in) {
 429                 /* Place READ protection SGLs before Data IN payload */
 430                 if (scsi_prot_sg_count(sc))
 431                         sgs[out_num + in_num++] = scsi_prot_sglist(sc);
 432                 sgs[out_num + in_num++] = in->sgl;
 433         }
 434
 435         return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC);
 436 }
 437
 438 static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq,
 439                              struct virtio_scsi_cmd *cmd,
 440                              size_t req_size, size_t resp_size)
 441 {
 442         unsigned long flags;
 443         int err;
 444         bool needs_kick = false;
 445
 446         spin_lock_irqsave(&vq->vq_lock, flags);
 447         err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size);
 448         if (!err)
 449                 needs_kick = virtqueue_kick_prepare(vq->vq);
 450
 451         spin_unlock_irqrestore(&vq->vq_lock, flags);
 452
 453         if (needs_kick)
 454                 virtqueue_notify(vq->vq);
 455         return err;
 456 }
 457
 458 static void virtio_scsi_init_hdr(struct virtio_device *vdev,
 459                                  struct virtio_scsi_cmd_req *cmd,
 460                                  struct scsi_cmnd *sc)
 461 {
 462         cmd->lun[0] = 1;
 463         cmd->lun[1] = sc->device->id;
 464         cmd->lun[2] = (sc->device->lun >> 8) | 0x40;
 465         cmd->lun[3] = sc->device->lun & 0xff;
 466         cmd->tag = cpu_to_virtio64(vdev, (unsigned long)sc);
 467         cmd->task_attr = VIRTIO_SCSI_S_SIMPLE;
 468         cmd->prio = 0;
 469         cmd->crn = 0;
 470 }
 471
 472 #ifdef CONFIG_BLK_DEV_INTEGRITY
 473 static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev,
 474                                     struct virtio_scsi_cmd_req_pi *cmd_pi,
 475                                     struct scsi_cmnd *sc)
 476 {
 477         struct request *rq = sc->request;
 478         struct blk_integrity *bi;
 479
 480         virtio_scsi_init_hdr(vdev, (struct virtio_scsi_cmd_req *)cmd_pi, sc);
 481
 482         if (!rq || !scsi_prot_sg_count(sc))
 483                 return;
 484
 485         bi = blk_get_integrity(rq->rq_disk);
 486
 487         if (sc->sc_data_direction == DMA_TO_DEVICE)
 488                 cmd_pi->pi_bytesout = cpu_to_virtio32(vdev,
 489                                                       bio_integrity_bytes(bi,
 490                                                         blk_rq_sectors(rq)));
 491         else if (sc->sc_data_direction == DMA_FROM_DEVICE)
 492                 cmd_pi->pi_bytesin = cpu_to_virtio32(vdev,
 493                                                      bio_integrity_bytes(bi,
 494                                                         blk_rq_sectors(rq)));
 495 }
 496 #endif
 497
 498 static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi,
 499                                                   struct scsi_cmnd *sc)
 500 {
 501         u32 tag = blk_mq_unique_tag(sc->request);
 502         u16 hwq = blk_mq_unique_tag_to_hwq(tag);
 503
 504         return &vscsi->req_vqs[hwq];
 505 }
 506
 507 static int virtscsi_queuecommand(struct Scsi_Host *shost,
 508                                  struct scsi_cmnd *sc)
 509 {
 510         struct virtio_scsi *vscsi = shost_priv(shost);
 511         struct virtio_scsi_vq *req_vq = virtscsi_pick_vq_mq(vscsi, sc);
 512         struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
 513         unsigned long flags;
 514         int req_size;
 515         int ret;
 516
 517         BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
 518
 519         /* TODO: check feature bit and fail if unsupported?  */
 520         BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
 521
 522         dev_dbg(&sc->device->sdev_gendev,
 523                 "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
 524
 525         cmd->sc = sc;
 526
 527         BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
 528
 529 #ifdef CONFIG_BLK_DEV_INTEGRITY
 530         if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) {
 531                 virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, sc);
 532                 memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len);
 533                 req_size = sizeof(cmd->req.cmd_pi);
 534         } else
 535 #endif
 536         {
 537                 virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, sc);
 538                 memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
 539                 req_size = sizeof(cmd->req.cmd);
 540         }
 541
 542         ret = virtscsi_kick_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd));
 543         if (ret == -EIO) {
 544                 cmd->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
 545                 spin_lock_irqsave(&req_vq->vq_lock, flags);
 546                 virtscsi_complete_cmd(vscsi, cmd);
 547                 spin_unlock_irqrestore(&req_vq->vq_lock, flags);
 548         } else if (ret != 0) {
 549                 return SCSI_MLQUEUE_HOST_BUSY;
 550         }
 551         return 0;
 552 }
 553
 554 static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
 555 {
 556         DECLARE_COMPLETION_ONSTACK(comp);
 557         int ret = FAILED;
 558
 559         cmd->comp = &comp;
 560         if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd,
 561                               sizeof cmd->req.tmf, sizeof cmd->resp.tmf) < 0)
 562                 goto out;
 563
 564         wait_for_completion(&comp);
 565         if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
 566             cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
 567                 ret = SUCCESS;
 568
 569         /*
 570          * The spec guarantees that all requests related to the TMF have
 571          * been completed, but the callback might not have run yet if
 572          * we're using independent interrupts (e.g. MSI).  Poll the
 573          * virtqueues once.
 574          *
 575          * In the abort case, sc->scsi_done will do nothing, because
 576          * the block layer must have detected a timeout and as a result
 577          * REQ_ATOM_COMPLETE has been set.
 578          */
 579         virtscsi_poll_requests(vscsi);
 580
 581 out:
 582         mempool_free(cmd, virtscsi_cmd_pool);
 583         return ret;
 584 }
 585
 586 static int virtscsi_device_reset(struct scsi_cmnd *sc)
 587 {
 588         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 589         struct virtio_scsi_cmd *cmd;
 590
 591         sdev_printk(KERN_INFO, sc->device, "device reset\n");
 592         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 593         if (!cmd)
 594                 return FAILED;
 595
 596         memset(cmd, 0, sizeof(*cmd));
 597         cmd->sc = sc;
 598         cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 599                 .type = VIRTIO_SCSI_T_TMF,
 600                 .subtype = cpu_to_virtio32(vscsi->vdev,
 601                                              VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET),
 602                 .lun[0] = 1,
 603                 .lun[1] = sc->device->id,
 604                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 605                 .lun[3] = sc->device->lun & 0xff,
 606         };
 607         return virtscsi_tmf(vscsi, cmd);
 608 }
 609
 610 static int virtscsi_device_alloc(struct scsi_device *sdevice)
 611 {
 612         /*
 613          * Passed through SCSI targets (e.g. with qemu's 'scsi-block')
 614          * may have transfer limits which come from the host SCSI
 615          * controller or something on the host side other than the
 616          * target itself.
 617          *
 618          * To make this work properly, the hypervisor can adjust the
 619          * target's VPD information to advertise these limits.  But
 620          * for that to work, the guest has to look at the VPD pages,
 621          * which we won't do by default if it is an SPC-2 device, even
 622          * if it does actually support it.
 623          *
 624          * So, set the blist to always try to read the VPD pages.
 625          */
 626         sdevice->sdev_bflags = BLIST_TRY_VPD_PAGES;
 627
 628         return 0;
 629 }
 630
 631
 632 /**
 633  * virtscsi_change_queue_depth() - Change a virtscsi target's queue depth
 634  * @sdev:       Virtscsi target whose queue depth to change
 635  * @qdepth:     New queue depth
 636  */
 637 static int virtscsi_change_queue_depth(struct scsi_device *sdev, int qdepth)
 638 {
 639         struct Scsi_Host *shost = sdev->host;
 640         int max_depth = shost->cmd_per_lun;
 641
 642         return scsi_change_queue_depth(sdev, min(max_depth, qdepth));
 643 }
 644
 645 static int virtscsi_abort(struct scsi_cmnd *sc)
 646 {
 647         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 648         struct virtio_scsi_cmd *cmd;
 649
 650         scmd_printk(KERN_INFO, sc, "abort\n");
 651         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 652         if (!cmd)
 653                 return FAILED;
 654
 655         memset(cmd, 0, sizeof(*cmd));
 656         cmd->sc = sc;
 657         cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 658                 .type = VIRTIO_SCSI_T_TMF,
 659                 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
 660                 .lun[0] = 1,
 661                 .lun[1] = sc->device->id,
 662                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 663                 .lun[3] = sc->device->lun & 0xff,
 664                 .tag = cpu_to_virtio64(vscsi->vdev, (unsigned long)sc),
 665         };
 666         return virtscsi_tmf(vscsi, cmd);
 667 }
 668
 669 static int virtscsi_map_queues(struct Scsi_Host *shost)
 670 {
 671         struct virtio_scsi *vscsi = shost_priv(shost);
 672         struct blk_mq_queue_map *qmap = &shost->tag_set.map[0];
 673
 674         return blk_mq_virtio_map_queues(qmap, vscsi->vdev, 2);
 675 }
 676
 677 /*
 678  * The host guarantees to respond to each command, although I/O
 679  * latencies might be higher than on bare metal.  Reset the timer
 680  * unconditionally to give the host a chance to perform EH.
 681  */
 682 static enum blk_eh_timer_return virtscsi_eh_timed_out(struct scsi_cmnd *scmnd)
 683 {
 684         return BLK_EH_RESET_TIMER;
 685 }
 686
 687 static struct scsi_host_template virtscsi_host_template = {
 688         .module = THIS_MODULE,
 689         .name = "Virtio SCSI HBA",
 690         .proc_name = "virtio_scsi",
 691         .this_id = -1,
 692         .cmd_size = sizeof(struct virtio_scsi_cmd),
 693         .queuecommand = virtscsi_queuecommand,
 694         .change_queue_depth = virtscsi_change_queue_depth,
 695         .eh_abort_handler = virtscsi_abort,
 696         .eh_device_reset_handler = virtscsi_device_reset,
 697         .eh_timed_out = virtscsi_eh_timed_out,
 698         .slave_alloc = virtscsi_device_alloc,
 699
 700         .dma_boundary = UINT_MAX,
 701         .map_queues = virtscsi_map_queues,
 702         .track_queue_depth = 1,
 703         .force_blk_mq = 1,
 704 };
 705
 706 #define virtscsi_config_get(vdev, fld) \
 707         ({ \
 708                 typeof(((struct virtio_scsi_config *)0)->fld) __val; \
 709                 virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \
 710                 __val; \
 711         })
 712
 713 #define virtscsi_config_set(vdev, fld, val) \
 714         do { \
 715                 typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
 716                 virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \
 717         } while(0)
 718
 719 static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
 720                              struct virtqueue *vq)
 721 {
 722         spin_lock_init(&virtscsi_vq->vq_lock);
 723         virtscsi_vq->vq = vq;
 724 }
 725
 726 static void virtscsi_remove_vqs(struct virtio_device *vdev)
 727 {
 728         /* Stop all the virtqueues. */
 729         vdev->config->reset(vdev);
 730         vdev->config->del_vqs(vdev);
 731 }
 732
 733 static int virtscsi_init(struct virtio_device *vdev,
 734                          struct virtio_scsi *vscsi)
 735 {
 736         int err;
 737         u32 i;
 738         u32 num_vqs;
 739         vq_callback_t **callbacks;
 740         const char **names;
 741         struct virtqueue **vqs;
 742         struct irq_affinity desc = { .pre_vectors = 2 };
 743
 744         num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;
 745         vqs = kmalloc_array(num_vqs, sizeof(struct virtqueue *), GFP_KERNEL);
 746         callbacks = kmalloc_array(num_vqs, sizeof(vq_callback_t *),
 747                                   GFP_KERNEL);
 748         names = kmalloc_array(num_vqs, sizeof(char *), GFP_KERNEL);
 749
 750         if (!callbacks || !vqs || !names) {
 751                 err = -ENOMEM;
 752                 goto out;
 753         }
 754
 755         callbacks[0] = virtscsi_ctrl_done;
 756         callbacks[1] = virtscsi_event_done;
 757         names[0] = "control";
 758         names[1] = "event";
 759         for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) {
 760                 callbacks[i] = virtscsi_req_done;
 761                 names[i] = "request";
 762         }
 763
 764         /* Discover virtqueues and write information to configuration.  */
 765         err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc);
 766         if (err)
 767                 goto out;
 768
 769         virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
 770         virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
 771         for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
 772                 virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
 773                                  vqs[i]);
 774
 775         virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
 776         virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
 777
 778         err = 0;
 779
 780 out:
 781         kfree(names);
 782         kfree(callbacks);
 783         kfree(vqs);
 784         if (err)
 785                 virtscsi_remove_vqs(vdev);
 786         return err;
 787 }
 788
 789 static int virtscsi_probe(struct virtio_device *vdev)
 790 {
 791         struct Scsi_Host *shost;
 792         struct virtio_scsi *vscsi;
 793         int err;
 794         u32 sg_elems, num_targets;
 795         u32 cmd_per_lun;
 796         u32 num_queues;
 797
 798         if (!vdev->config->get) {
 799                 dev_err(&vdev->dev, "%s failure: config access disabled\n",
 800                         __func__);
 801                 return -EINVAL;
 802         }
 803
 804         /* We need to know how many queues before we allocate. */
 805         num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
 806
 807         num_targets = virtscsi_config_get(vdev, max_target) + 1;
 808
 809         shost = scsi_host_alloc(&virtscsi_host_template,
 810                 sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues);
 811         if (!shost)
 812                 return -ENOMEM;
 813
 814         sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
 815         shost->sg_tablesize = sg_elems;
 816         vscsi = shost_priv(shost);
 817         vscsi->vdev = vdev;
 818         vscsi->num_queues = num_queues;
 819         vdev->priv = shost;
 820
 821         err = virtscsi_init(vdev, vscsi);
 822         if (err)
 823                 goto virtscsi_init_failed;
 824
 825         shost->can_queue = virtqueue_get_vring_size(vscsi->req_vqs[0].vq);
 826
 827         cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
 828         shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
 829         shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
 830
 831         /* LUNs > 256 are reported with format 1, so they go in the range
 832          * 16640-32767.
 833          */
 834         shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
 835         shost->max_id = num_targets;
 836         shost->max_channel = 0;
 837         shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
 838         shost->nr_hw_queues = num_queues;
 839
 840 #ifdef CONFIG_BLK_DEV_INTEGRITY
 841         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
 842                 int host_prot;
 843
 844                 host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
 845                             SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
 846                             SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
 847
 848                 scsi_host_set_prot(shost, host_prot);
 849                 scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC);
 850         }
 851 #endif
 852
 853         err = scsi_add_host(shost, &vdev->dev);
 854         if (err)
 855                 goto scsi_add_host_failed;
 856
 857         virtio_device_ready(vdev);
 858
 859         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 860                 virtscsi_kick_event_all(vscsi);
 861
 862         scsi_scan_host(shost);
 863         return 0;
 864
 865 scsi_add_host_failed:
 866         vdev->config->del_vqs(vdev);
 867 virtscsi_init_failed:
 868         scsi_host_put(shost);
 869         return err;
 870 }
 871
 872 static void virtscsi_remove(struct virtio_device *vdev)
 873 {
 874         struct Scsi_Host *shost = virtio_scsi_host(vdev);
 875         struct virtio_scsi *vscsi = shost_priv(shost);
 876
 877         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 878                 virtscsi_cancel_event_work(vscsi);
 879
 880         scsi_remove_host(shost);
 881         virtscsi_remove_vqs(vdev);
 882         scsi_host_put(shost);
 883 }
 884
 885 #ifdef CONFIG_PM_SLEEP
 886 static int virtscsi_freeze(struct virtio_device *vdev)
 887 {
 888         virtscsi_remove_vqs(vdev);
 889         return 0;
 890 }
 891
 892 static int virtscsi_restore(struct virtio_device *vdev)
 893 {
 894         struct Scsi_Host *sh = virtio_scsi_host(vdev);
 895         struct virtio_scsi *vscsi = shost_priv(sh);
 896         int err;
 897
 898         err = virtscsi_init(vdev, vscsi);
 899         if (err)
 900                 return err;
 901
 902         virtio_device_ready(vdev);
 903
 904         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 905                 virtscsi_kick_event_all(vscsi);
 906
 907         return err;
 908 }
 909 #endif
 910
 911 static struct virtio_device_id id_table[] = {
 912         { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
 913         { 0 },
 914 };
 915
 916 static unsigned int features[] = {
 917         VIRTIO_SCSI_F_HOTPLUG,
 918         VIRTIO_SCSI_F_CHANGE,
 919 #ifdef CONFIG_BLK_DEV_INTEGRITY
 920         VIRTIO_SCSI_F_T10_PI,
 921 #endif
 922 };
 923
 924 static struct virtio_driver virtio_scsi_driver = {
 925         .feature_table = features,
 926         .feature_table_size = ARRAY_SIZE(features),
 927         .driver.name = KBUILD_MODNAME,
 928         .driver.owner = THIS_MODULE,
 929         .id_table = id_table,
 930         .probe = virtscsi_probe,
 931 #ifdef CONFIG_PM_SLEEP
 932         .freeze = virtscsi_freeze,
 933         .restore = virtscsi_restore,
 934 #endif
 935         .remove = virtscsi_remove,
 936 };
 937
 938 static int __init init(void)
 939 {
 940         int ret = -ENOMEM;
 941
 942         virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
 943         if (!virtscsi_cmd_cache) {
 944                 pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
 945                 goto error;
 946         }
 947
 948
 949         virtscsi_cmd_pool =
 950                 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
 951                                          virtscsi_cmd_cache);
 952         if (!virtscsi_cmd_pool) {
 953                 pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
 954                 goto error;
 955         }
 956         ret = register_virtio_driver(&virtio_scsi_driver);
 957         if (ret < 0)
 958                 goto error;
 959
 960         return 0;
 961
 962 error:
 963         if (virtscsi_cmd_pool) {
 964                 mempool_destroy(virtscsi_cmd_pool);
 965                 virtscsi_cmd_pool = NULL;
 966         }
 967         if (virtscsi_cmd_cache) {
 968                 kmem_cache_destroy(virtscsi_cmd_cache);
 969                 virtscsi_cmd_cache = NULL;
 970         }
 971         return ret;
 972 }
 973
 974 static void __exit fini(void)
 975 {
 976         unregister_virtio_driver(&virtio_scsi_driver);
 977         mempool_destroy(virtscsi_cmd_pool);
 978         kmem_cache_destroy(virtscsi_cmd_cache);
 979 }
 980 module_init(init);
 981 module_exit(fini);
 982
 983 MODULE_DEVICE_TABLE(virtio, id_table);
 984 MODULE_DESCRIPTION("Virtio SCSI HBA driver");
 985 MODULE_LICENSE("GPL");