drivers/scsi/virtio_scsi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Virtio SCSI HBA driver
   4  *
   5  * Copyright IBM Corp. 2010
   6  * Copyright Red Hat, Inc. 2011
   7  *
   8  * Authors:
   9  *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.com>
  10  *  Paolo Bonzini   <pbonzini@redhat.com>
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/module.h>
  16 #include <linux/slab.h>
  17 #include <linux/mempool.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/virtio.h>
  20 #include <linux/virtio_ids.h>
  21 #include <linux/virtio_config.h>
  22 #include <linux/virtio_scsi.h>
  23 #include <linux/cpu.h>
  24 #include <linux/blkdev.h>
  25 #include <scsi/scsi_host.h>
  26 #include <scsi/scsi_device.h>
  27 #include <scsi/scsi_cmnd.h>
  28 #include <scsi/scsi_tcq.h>
  29 #include <scsi/scsi_devinfo.h>
  30 #include <linux/seqlock.h>
  31 #include <linux/blk-mq-virtio.h>
  32
  33 #define VIRTIO_SCSI_MEMPOOL_SZ 64
  34 #define VIRTIO_SCSI_EVENT_LEN 8
  35 #define VIRTIO_SCSI_VQ_BASE 2
  36
  37 /* Command queue element */
  38 struct virtio_scsi_cmd {
  39         struct scsi_cmnd *sc;
  40         struct completion *comp;
  41         union {
  42                 struct virtio_scsi_cmd_req       cmd;
  43                 struct virtio_scsi_cmd_req_pi    cmd_pi;
  44                 struct virtio_scsi_ctrl_tmf_req  tmf;
  45                 struct virtio_scsi_ctrl_an_req   an;
  46         } req;
  47         union {
  48                 struct virtio_scsi_cmd_resp      cmd;
  49                 struct virtio_scsi_ctrl_tmf_resp tmf;
  50                 struct virtio_scsi_ctrl_an_resp  an;
  51                 struct virtio_scsi_event         evt;
  52         } resp;
  53 } ____cacheline_aligned_in_smp;
  54
  55 struct virtio_scsi_event_node {
  56         struct virtio_scsi *vscsi;
  57         struct virtio_scsi_event event;
  58         struct work_struct work;
  59 };
  60
  61 struct virtio_scsi_vq {
  62         /* Protects vq */
  63         spinlock_t vq_lock;
  64
  65         struct virtqueue *vq;
  66 };
  67
  68 /* Driver instance state */
  69 struct virtio_scsi {
  70         struct virtio_device *vdev;
  71
  72         /* Get some buffers ready for event vq */
  73         struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN];
  74
  75         u32 num_queues;
  76
  77         /* If the affinity hint is set for virtqueues */
  78         bool affinity_hint_set;
  79
  80         struct hlist_node node;
  81
  82         /* Protected by event_vq lock */
  83         bool stop_events;
  84
  85         struct virtio_scsi_vq ctrl_vq;
  86         struct virtio_scsi_vq event_vq;
  87         struct virtio_scsi_vq req_vqs[];
  88 };
  89
  90 static struct kmem_cache *virtscsi_cmd_cache;
  91 static mempool_t *virtscsi_cmd_pool;
  92
  93 static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
  94 {
  95         return vdev->priv;
  96 }
  97
  98 static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
  99 {
 100         if (resid)
 101                 scsi_set_resid(sc, resid);
 102 }
 103
 104 /**
 105  * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
 106  *
 107  * Called with vq_lock held.
 108  */
 109 static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
 110 {
 111         struct virtio_scsi_cmd *cmd = buf;
 112         struct scsi_cmnd *sc = cmd->sc;
 113         struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
 114
 115         dev_dbg(&sc->device->sdev_gendev,
 116                 "cmd %p response %u status %#02x sense_len %u\n",
 117                 sc, resp->response, resp->status, resp->sense_len);
 118
 119         sc->result = resp->status;
 120         virtscsi_compute_resid(sc, virtio32_to_cpu(vscsi->vdev, resp->resid));
 121         switch (resp->response) {
 122         case VIRTIO_SCSI_S_OK:
 123                 set_host_byte(sc, DID_OK);
 124                 break;
 125         case VIRTIO_SCSI_S_OVERRUN:
 126                 set_host_byte(sc, DID_ERROR);
 127                 break;
 128         case VIRTIO_SCSI_S_ABORTED:
 129                 set_host_byte(sc, DID_ABORT);
 130                 break;
 131         case VIRTIO_SCSI_S_BAD_TARGET:
 132                 set_host_byte(sc, DID_BAD_TARGET);
 133                 break;
 134         case VIRTIO_SCSI_S_RESET:
 135                 set_host_byte(sc, DID_RESET);
 136                 break;
 137         case VIRTIO_SCSI_S_BUSY:
 138                 set_host_byte(sc, DID_BUS_BUSY);
 139                 break;
 140         case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
 141                 set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
 142                 break;
 143         case VIRTIO_SCSI_S_TARGET_FAILURE:
 144                 set_host_byte(sc, DID_TARGET_FAILURE);
 145                 break;
 146         case VIRTIO_SCSI_S_NEXUS_FAILURE:
 147                 set_host_byte(sc, DID_NEXUS_FAILURE);
 148                 break;
 149         default:
 150                 scmd_printk(KERN_WARNING, sc, "Unknown response %d",
 151                             resp->response);
 152                 /* fall through */
 153         case VIRTIO_SCSI_S_FAILURE:
 154                 set_host_byte(sc, DID_ERROR);
 155                 break;
 156         }
 157
 158         WARN_ON(virtio32_to_cpu(vscsi->vdev, resp->sense_len) >
 159                 VIRTIO_SCSI_SENSE_SIZE);
 160         if (sc->sense_buffer) {
 161                 memcpy(sc->sense_buffer, resp->sense,
 162                        min_t(u32,
 163                              virtio32_to_cpu(vscsi->vdev, resp->sense_len),
 164                              VIRTIO_SCSI_SENSE_SIZE));
 165                 if (resp->sense_len)
 166                         set_driver_byte(sc, DRIVER_SENSE);
 167         }
 168
 169         sc->scsi_done(sc);
 170 }
 171
 172 static void virtscsi_vq_done(struct virtio_scsi *vscsi,
 173                              struct virtio_scsi_vq *virtscsi_vq,
 174                              void (*fn)(struct virtio_scsi *vscsi, void *buf))
 175 {
 176         void *buf;
 177         unsigned int len;
 178         unsigned long flags;
 179         struct virtqueue *vq = virtscsi_vq->vq;
 180
 181         spin_lock_irqsave(&virtscsi_vq->vq_lock, flags);
 182         do {
 183                 virtqueue_disable_cb(vq);
 184                 while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
 185                         fn(vscsi, buf);
 186
 187                 if (unlikely(virtqueue_is_broken(vq)))
 188                         break;
 189         } while (!virtqueue_enable_cb(vq));
 190         spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
 191 }
 192
 193 static void virtscsi_req_done(struct virtqueue *vq)
 194 {
 195         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 196         struct virtio_scsi *vscsi = shost_priv(sh);
 197         int index = vq->index - VIRTIO_SCSI_VQ_BASE;
 198         struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index];
 199
 200         virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd);
 201 };
 202
 203 static void virtscsi_poll_requests(struct virtio_scsi *vscsi)
 204 {
 205         int i, num_vqs;
 206
 207         num_vqs = vscsi->num_queues;
 208         for (i = 0; i < num_vqs; i++)
 209                 virtscsi_vq_done(vscsi, &vscsi->req_vqs[i],
 210                                  virtscsi_complete_cmd);
 211 }
 212
 213 static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)
 214 {
 215         struct virtio_scsi_cmd *cmd = buf;
 216
 217         if (cmd->comp)
 218                 complete(cmd->comp);
 219 }
 220
 221 static void virtscsi_ctrl_done(struct virtqueue *vq)
 222 {
 223         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 224         struct virtio_scsi *vscsi = shost_priv(sh);
 225
 226         virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free);
 227 };
 228
 229 static void virtscsi_handle_event(struct work_struct *work);
 230
 231 static int virtscsi_kick_event(struct virtio_scsi *vscsi,
 232                                struct virtio_scsi_event_node *event_node)
 233 {
 234         int err;
 235         struct scatterlist sg;
 236         unsigned long flags;
 237
 238         INIT_WORK(&event_node->work, virtscsi_handle_event);
 239         sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
 240
 241         spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
 242
 243         err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node,
 244                                   GFP_ATOMIC);
 245         if (!err)
 246                 virtqueue_kick(vscsi->event_vq.vq);
 247
 248         spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
 249
 250         return err;
 251 }
 252
 253 static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
 254 {
 255         int i;
 256
 257         for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
 258                 vscsi->event_list[i].vscsi = vscsi;
 259                 virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
 260         }
 261
 262         return 0;
 263 }
 264
 265 static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
 266 {
 267         int i;
 268
 269         /* Stop scheduling work before calling cancel_work_sync.  */
 270         spin_lock_irq(&vscsi->event_vq.vq_lock);
 271         vscsi->stop_events = true;
 272         spin_unlock_irq(&vscsi->event_vq.vq_lock);
 273
 274         for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
 275                 cancel_work_sync(&vscsi->event_list[i].work);
 276 }
 277
 278 static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
 279                                             struct virtio_scsi_event *event)
 280 {
 281         struct scsi_device *sdev;
 282         struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 283         unsigned int target = event->lun[1];
 284         unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 285
 286         switch (virtio32_to_cpu(vscsi->vdev, event->reason)) {
 287         case VIRTIO_SCSI_EVT_RESET_RESCAN:
 288                 scsi_add_device(shost, 0, target, lun);
 289                 break;
 290         case VIRTIO_SCSI_EVT_RESET_REMOVED:
 291                 sdev = scsi_device_lookup(shost, 0, target, lun);
 292                 if (sdev) {
 293                         scsi_remove_device(sdev);
 294                         scsi_device_put(sdev);
 295                 } else {
 296                         pr_err("SCSI device %d 0 %d %d not found\n",
 297                                 shost->host_no, target, lun);
 298                 }
 299                 break;
 300         default:
 301                 pr_info("Unsupport virtio scsi event reason %x\n", event->reason);
 302         }
 303 }
 304
 305 static void virtscsi_handle_param_change(struct virtio_scsi *vscsi,
 306                                          struct virtio_scsi_event *event)
 307 {
 308         struct scsi_device *sdev;
 309         struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 310         unsigned int target = event->lun[1];
 311         unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 312         u8 asc = virtio32_to_cpu(vscsi->vdev, event->reason) & 255;
 313         u8 ascq = virtio32_to_cpu(vscsi->vdev, event->reason) >> 8;
 314
 315         sdev = scsi_device_lookup(shost, 0, target, lun);
 316         if (!sdev) {
 317                 pr_err("SCSI device %d 0 %d %d not found\n",
 318                         shost->host_no, target, lun);
 319                 return;
 320         }
 321
 322         /* Handle "Parameters changed", "Mode parameters changed", and
 323            "Capacity data has changed".  */
 324         if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
 325                 scsi_rescan_device(&sdev->sdev_gendev);
 326
 327         scsi_device_put(sdev);
 328 }
 329
 330 static void virtscsi_handle_event(struct work_struct *work)
 331 {
 332         struct virtio_scsi_event_node *event_node =
 333                 container_of(work, struct virtio_scsi_event_node, work);
 334         struct virtio_scsi *vscsi = event_node->vscsi;
 335         struct virtio_scsi_event *event = &event_node->event;
 336
 337         if (event->event &
 338             cpu_to_virtio32(vscsi->vdev, VIRTIO_SCSI_T_EVENTS_MISSED)) {
 339                 event->event &= ~cpu_to_virtio32(vscsi->vdev,
 340                                                    VIRTIO_SCSI_T_EVENTS_MISSED);
 341                 scsi_scan_host(virtio_scsi_host(vscsi->vdev));
 342         }
 343
 344         switch (virtio32_to_cpu(vscsi->vdev, event->event)) {
 345         case VIRTIO_SCSI_T_NO_EVENT:
 346                 break;
 347         case VIRTIO_SCSI_T_TRANSPORT_RESET:
 348                 virtscsi_handle_transport_reset(vscsi, event);
 349                 break;
 350         case VIRTIO_SCSI_T_PARAM_CHANGE:
 351                 virtscsi_handle_param_change(vscsi, event);
 352                 break;
 353         default:
 354                 pr_err("Unsupport virtio scsi event %x\n", event->event);
 355         }
 356         virtscsi_kick_event(vscsi, event_node);
 357 }
 358
 359 static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf)
 360 {
 361         struct virtio_scsi_event_node *event_node = buf;
 362
 363         if (!vscsi->stop_events)
 364                 queue_work(system_freezable_wq, &event_node->work);
 365 }
 366
 367 static void virtscsi_event_done(struct virtqueue *vq)
 368 {
 369         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 370         struct virtio_scsi *vscsi = shost_priv(sh);
 371
 372         virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event);
 373 };
 374
 375 /**
 376  * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue
 377  * @vq          : the struct virtqueue we're talking about
 378  * @cmd         : command structure
 379  * @req_size    : size of the request buffer
 380  * @resp_size   : size of the response buffer
 381  */
 382 static int virtscsi_add_cmd(struct virtqueue *vq,
 383                             struct virtio_scsi_cmd *cmd,
 384                             size_t req_size, size_t resp_size)
 385 {
 386         struct scsi_cmnd *sc = cmd->sc;
 387         struct scatterlist *sgs[6], req, resp;
 388         struct sg_table *out, *in;
 389         unsigned out_num = 0, in_num = 0;
 390
 391         out = in = NULL;
 392
 393         if (sc && sc->sc_data_direction != DMA_NONE) {
 394                 if (sc->sc_data_direction != DMA_FROM_DEVICE)
 395                         out = &sc->sdb.table;
 396                 if (sc->sc_data_direction != DMA_TO_DEVICE)
 397                         in = &sc->sdb.table;
 398         }
 399
 400         /* Request header.  */
 401         sg_init_one(&req, &cmd->req, req_size);
 402         sgs[out_num++] = &req;
 403
 404         /* Data-out buffer.  */
 405         if (out) {
 406                 /* Place WRITE protection SGLs before Data OUT payload */
 407                 if (scsi_prot_sg_count(sc))
 408                         sgs[out_num++] = scsi_prot_sglist(sc);
 409                 sgs[out_num++] = out->sgl;
 410         }
 411
 412         /* Response header.  */
 413         sg_init_one(&resp, &cmd->resp, resp_size);
 414         sgs[out_num + in_num++] = &resp;
 415
 416         /* Data-in buffer */
 417         if (in) {
 418                 /* Place READ protection SGLs before Data IN payload */
 419                 if (scsi_prot_sg_count(sc))
 420                         sgs[out_num + in_num++] = scsi_prot_sglist(sc);
 421                 sgs[out_num + in_num++] = in->sgl;
 422         }
 423
 424         return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC);
 425 }
 426
 427 static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq,
 428                              struct virtio_scsi_cmd *cmd,
 429                              size_t req_size, size_t resp_size)
 430 {
 431         unsigned long flags;
 432         int err;
 433         bool needs_kick = false;
 434
 435         spin_lock_irqsave(&vq->vq_lock, flags);
 436         err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size);
 437         if (!err)
 438                 needs_kick = virtqueue_kick_prepare(vq->vq);
 439
 440         spin_unlock_irqrestore(&vq->vq_lock, flags);
 441
 442         if (needs_kick)
 443                 virtqueue_notify(vq->vq);
 444         return err;
 445 }
 446
 447 static void virtio_scsi_init_hdr(struct virtio_device *vdev,
 448                                  struct virtio_scsi_cmd_req *cmd,
 449                                  struct scsi_cmnd *sc)
 450 {
 451         cmd->lun[0] = 1;
 452         cmd->lun[1] = sc->device->id;
 453         cmd->lun[2] = (sc->device->lun >> 8) | 0x40;
 454         cmd->lun[3] = sc->device->lun & 0xff;
 455         cmd->tag = cpu_to_virtio64(vdev, (unsigned long)sc);
 456         cmd->task_attr = VIRTIO_SCSI_S_SIMPLE;
 457         cmd->prio = 0;
 458         cmd->crn = 0;
 459 }
 460
 461 #ifdef CONFIG_BLK_DEV_INTEGRITY
 462 static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev,
 463                                     struct virtio_scsi_cmd_req_pi *cmd_pi,
 464                                     struct scsi_cmnd *sc)
 465 {
 466         struct request *rq = sc->request;
 467         struct blk_integrity *bi;
 468
 469         virtio_scsi_init_hdr(vdev, (struct virtio_scsi_cmd_req *)cmd_pi, sc);
 470
 471         if (!rq || !scsi_prot_sg_count(sc))
 472                 return;
 473
 474         bi = blk_get_integrity(rq->rq_disk);
 475
 476         if (sc->sc_data_direction == DMA_TO_DEVICE)
 477                 cmd_pi->pi_bytesout = cpu_to_virtio32(vdev,
 478                                                       bio_integrity_bytes(bi,
 479                                                         blk_rq_sectors(rq)));
 480         else if (sc->sc_data_direction == DMA_FROM_DEVICE)
 481                 cmd_pi->pi_bytesin = cpu_to_virtio32(vdev,
 482                                                      bio_integrity_bytes(bi,
 483                                                         blk_rq_sectors(rq)));
 484 }
 485 #endif
 486
 487 static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi,
 488                                                   struct scsi_cmnd *sc)
 489 {
 490         u32 tag = blk_mq_unique_tag(sc->request);
 491         u16 hwq = blk_mq_unique_tag_to_hwq(tag);
 492
 493         return &vscsi->req_vqs[hwq];
 494 }
 495
 496 static int virtscsi_queuecommand(struct Scsi_Host *shost,
 497                                  struct scsi_cmnd *sc)
 498 {
 499         struct virtio_scsi *vscsi = shost_priv(shost);
 500         struct virtio_scsi_vq *req_vq = virtscsi_pick_vq_mq(vscsi, sc);
 501         struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
 502         unsigned long flags;
 503         int req_size;
 504         int ret;
 505
 506         BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
 507
 508         /* TODO: check feature bit and fail if unsupported?  */
 509         BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
 510
 511         dev_dbg(&sc->device->sdev_gendev,
 512                 "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
 513
 514         cmd->sc = sc;
 515
 516         BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
 517
 518 #ifdef CONFIG_BLK_DEV_INTEGRITY
 519         if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) {
 520                 virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, sc);
 521                 memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len);
 522                 req_size = sizeof(cmd->req.cmd_pi);
 523         } else
 524 #endif
 525         {
 526                 virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, sc);
 527                 memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
 528                 req_size = sizeof(cmd->req.cmd);
 529         }
 530
 531         ret = virtscsi_kick_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd));
 532         if (ret == -EIO) {
 533                 cmd->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
 534                 spin_lock_irqsave(&req_vq->vq_lock, flags);
 535                 virtscsi_complete_cmd(vscsi, cmd);
 536                 spin_unlock_irqrestore(&req_vq->vq_lock, flags);
 537         } else if (ret != 0) {
 538                 return SCSI_MLQUEUE_HOST_BUSY;
 539         }
 540         return 0;
 541 }
 542
 543 static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
 544 {
 545         DECLARE_COMPLETION_ONSTACK(comp);
 546         int ret = FAILED;
 547
 548         cmd->comp = &comp;
 549         if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd,
 550                               sizeof cmd->req.tmf, sizeof cmd->resp.tmf) < 0)
 551                 goto out;
 552
 553         wait_for_completion(&comp);
 554         if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
 555             cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
 556                 ret = SUCCESS;
 557
 558         /*
 559          * The spec guarantees that all requests related to the TMF have
 560          * been completed, but the callback might not have run yet if
 561          * we're using independent interrupts (e.g. MSI).  Poll the
 562          * virtqueues once.
 563          *
 564          * In the abort case, sc->scsi_done will do nothing, because
 565          * the block layer must have detected a timeout and as a result
 566          * REQ_ATOM_COMPLETE has been set.
 567          */
 568         virtscsi_poll_requests(vscsi);
 569
 570 out:
 571         mempool_free(cmd, virtscsi_cmd_pool);
 572         return ret;
 573 }
 574
 575 static int virtscsi_device_reset(struct scsi_cmnd *sc)
 576 {
 577         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 578         struct virtio_scsi_cmd *cmd;
 579
 580         sdev_printk(KERN_INFO, sc->device, "device reset\n");
 581         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 582         if (!cmd)
 583                 return FAILED;
 584
 585         memset(cmd, 0, sizeof(*cmd));
 586         cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 587                 .type = VIRTIO_SCSI_T_TMF,
 588                 .subtype = cpu_to_virtio32(vscsi->vdev,
 589                                              VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET),
 590                 .lun[0] = 1,
 591                 .lun[1] = sc->device->id,
 592                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 593                 .lun[3] = sc->device->lun & 0xff,
 594         };
 595         return virtscsi_tmf(vscsi, cmd);
 596 }
 597
 598 static int virtscsi_device_alloc(struct scsi_device *sdevice)
 599 {
 600         /*
 601          * Passed through SCSI targets (e.g. with qemu's 'scsi-block')
 602          * may have transfer limits which come from the host SCSI
 603          * controller or something on the host side other than the
 604          * target itself.
 605          *
 606          * To make this work properly, the hypervisor can adjust the
 607          * target's VPD information to advertise these limits.  But
 608          * for that to work, the guest has to look at the VPD pages,
 609          * which we won't do by default if it is an SPC-2 device, even
 610          * if it does actually support it.
 611          *
 612          * So, set the blist to always try to read the VPD pages.
 613          */
 614         sdevice->sdev_bflags = BLIST_TRY_VPD_PAGES;
 615
 616         return 0;
 617 }
 618
 619
 620 /**
 621  * virtscsi_change_queue_depth() - Change a virtscsi target's queue depth
 622  * @sdev:       Virtscsi target whose queue depth to change
 623  * @qdepth:     New queue depth
 624  */
 625 static int virtscsi_change_queue_depth(struct scsi_device *sdev, int qdepth)
 626 {
 627         struct Scsi_Host *shost = sdev->host;
 628         int max_depth = shost->cmd_per_lun;
 629
 630         return scsi_change_queue_depth(sdev, min(max_depth, qdepth));
 631 }
 632
 633 static int virtscsi_abort(struct scsi_cmnd *sc)
 634 {
 635         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 636         struct virtio_scsi_cmd *cmd;
 637
 638         scmd_printk(KERN_INFO, sc, "abort\n");
 639         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 640         if (!cmd)
 641                 return FAILED;
 642
 643         memset(cmd, 0, sizeof(*cmd));
 644         cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 645                 .type = VIRTIO_SCSI_T_TMF,
 646                 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
 647                 .lun[0] = 1,
 648                 .lun[1] = sc->device->id,
 649                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 650                 .lun[3] = sc->device->lun & 0xff,
 651                 .tag = cpu_to_virtio64(vscsi->vdev, (unsigned long)sc),
 652         };
 653         return virtscsi_tmf(vscsi, cmd);
 654 }
 655
 656 static int virtscsi_map_queues(struct Scsi_Host *shost)
 657 {
 658         struct virtio_scsi *vscsi = shost_priv(shost);
 659         struct blk_mq_queue_map *qmap = &shost->tag_set.map[HCTX_TYPE_DEFAULT];
 660
 661         return blk_mq_virtio_map_queues(qmap, vscsi->vdev, 2);
 662 }
 663
 664 /*
 665  * The host guarantees to respond to each command, although I/O
 666  * latencies might be higher than on bare metal.  Reset the timer
 667  * unconditionally to give the host a chance to perform EH.
 668  */
 669 static enum blk_eh_timer_return virtscsi_eh_timed_out(struct scsi_cmnd *scmnd)
 670 {
 671         return BLK_EH_RESET_TIMER;
 672 }
 673
 674 static struct scsi_host_template virtscsi_host_template = {
 675         .module = THIS_MODULE,
 676         .name = "Virtio SCSI HBA",
 677         .proc_name = "virtio_scsi",
 678         .this_id = -1,
 679         .cmd_size = sizeof(struct virtio_scsi_cmd),
 680         .queuecommand = virtscsi_queuecommand,
 681         .change_queue_depth = virtscsi_change_queue_depth,
 682         .eh_abort_handler = virtscsi_abort,
 683         .eh_device_reset_handler = virtscsi_device_reset,
 684         .eh_timed_out = virtscsi_eh_timed_out,
 685         .slave_alloc = virtscsi_device_alloc,
 686
 687         .dma_boundary = UINT_MAX,
 688         .map_queues = virtscsi_map_queues,
 689         .track_queue_depth = 1,
 690         .force_blk_mq = 1,
 691 };
 692
 693 #define virtscsi_config_get(vdev, fld) \
 694         ({ \
 695                 typeof(((struct virtio_scsi_config *)0)->fld) __val; \
 696                 virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \
 697                 __val; \
 698         })
 699
 700 #define virtscsi_config_set(vdev, fld, val) \
 701         do { \
 702                 typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
 703                 virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \
 704         } while(0)
 705
 706 static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
 707                              struct virtqueue *vq)
 708 {
 709         spin_lock_init(&virtscsi_vq->vq_lock);
 710         virtscsi_vq->vq = vq;
 711 }
 712
 713 static void virtscsi_remove_vqs(struct virtio_device *vdev)
 714 {
 715         /* Stop all the virtqueues. */
 716         vdev->config->reset(vdev);
 717         vdev->config->del_vqs(vdev);
 718 }
 719
 720 static int virtscsi_init(struct virtio_device *vdev,
 721                          struct virtio_scsi *vscsi)
 722 {
 723         int err;
 724         u32 i;
 725         u32 num_vqs;
 726         vq_callback_t **callbacks;
 727         const char **names;
 728         struct virtqueue **vqs;
 729         struct irq_affinity desc = { .pre_vectors = 2 };
 730
 731         num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;
 732         vqs = kmalloc_array(num_vqs, sizeof(struct virtqueue *), GFP_KERNEL);
 733         callbacks = kmalloc_array(num_vqs, sizeof(vq_callback_t *),
 734                                   GFP_KERNEL);
 735         names = kmalloc_array(num_vqs, sizeof(char *), GFP_KERNEL);
 736
 737         if (!callbacks || !vqs || !names) {
 738                 err = -ENOMEM;
 739                 goto out;
 740         }
 741
 742         callbacks[0] = virtscsi_ctrl_done;
 743         callbacks[1] = virtscsi_event_done;
 744         names[0] = "control";
 745         names[1] = "event";
 746         for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) {
 747                 callbacks[i] = virtscsi_req_done;
 748                 names[i] = "request";
 749         }
 750
 751         /* Discover virtqueues and write information to configuration.  */
 752         err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc);
 753         if (err)
 754                 goto out;
 755
 756         virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
 757         virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
 758         for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
 759                 virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
 760                                  vqs[i]);
 761
 762         virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
 763         virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
 764
 765         err = 0;
 766
 767 out:
 768         kfree(names);
 769         kfree(callbacks);
 770         kfree(vqs);
 771         if (err)
 772                 virtscsi_remove_vqs(vdev);
 773         return err;
 774 }
 775
 776 static int virtscsi_probe(struct virtio_device *vdev)
 777 {
 778         struct Scsi_Host *shost;
 779         struct virtio_scsi *vscsi;
 780         int err;
 781         u32 sg_elems, num_targets;
 782         u32 cmd_per_lun;
 783         u32 num_queues;
 784
 785         if (!vdev->config->get) {
 786                 dev_err(&vdev->dev, "%s failure: config access disabled\n",
 787                         __func__);
 788                 return -EINVAL;
 789         }
 790
 791         /* We need to know how many queues before we allocate. */
 792         num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
 793         num_queues = min_t(unsigned int, nr_cpu_ids, num_queues);
 794
 795         num_targets = virtscsi_config_get(vdev, max_target) + 1;
 796
 797         shost = scsi_host_alloc(&virtscsi_host_template,
 798                 sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues);
 799         if (!shost)
 800                 return -ENOMEM;
 801
 802         sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
 803         shost->sg_tablesize = sg_elems;
 804         vscsi = shost_priv(shost);
 805         vscsi->vdev = vdev;
 806         vscsi->num_queues = num_queues;
 807         vdev->priv = shost;
 808
 809         err = virtscsi_init(vdev, vscsi);
 810         if (err)
 811                 goto virtscsi_init_failed;
 812
 813         shost->can_queue = virtqueue_get_vring_size(vscsi->req_vqs[0].vq);
 814
 815         cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
 816         shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
 817         shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
 818
 819         /* LUNs > 256 are reported with format 1, so they go in the range
 820          * 16640-32767.
 821          */
 822         shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
 823         shost->max_id = num_targets;
 824         shost->max_channel = 0;
 825         shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
 826         shost->nr_hw_queues = num_queues;
 827
 828 #ifdef CONFIG_BLK_DEV_INTEGRITY
 829         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
 830                 int host_prot;
 831
 832                 host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
 833                             SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
 834                             SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
 835
 836                 scsi_host_set_prot(shost, host_prot);
 837                 scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC);
 838         }
 839 #endif
 840
 841         err = scsi_add_host(shost, &vdev->dev);
 842         if (err)
 843                 goto scsi_add_host_failed;
 844
 845         virtio_device_ready(vdev);
 846
 847         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 848                 virtscsi_kick_event_all(vscsi);
 849
 850         scsi_scan_host(shost);
 851         return 0;
 852
 853 scsi_add_host_failed:
 854         vdev->config->del_vqs(vdev);
 855 virtscsi_init_failed:
 856         scsi_host_put(shost);
 857         return err;
 858 }
 859
 860 static void virtscsi_remove(struct virtio_device *vdev)
 861 {
 862         struct Scsi_Host *shost = virtio_scsi_host(vdev);
 863         struct virtio_scsi *vscsi = shost_priv(shost);
 864
 865         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 866                 virtscsi_cancel_event_work(vscsi);
 867
 868         scsi_remove_host(shost);
 869         virtscsi_remove_vqs(vdev);
 870         scsi_host_put(shost);
 871 }
 872
 873 #ifdef CONFIG_PM_SLEEP
 874 static int virtscsi_freeze(struct virtio_device *vdev)
 875 {
 876         virtscsi_remove_vqs(vdev);
 877         return 0;
 878 }
 879
 880 static int virtscsi_restore(struct virtio_device *vdev)
 881 {
 882         struct Scsi_Host *sh = virtio_scsi_host(vdev);
 883         struct virtio_scsi *vscsi = shost_priv(sh);
 884         int err;
 885
 886         err = virtscsi_init(vdev, vscsi);
 887         if (err)
 888                 return err;
 889
 890         virtio_device_ready(vdev);
 891
 892         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 893                 virtscsi_kick_event_all(vscsi);
 894
 895         return err;
 896 }
 897 #endif
 898
 899 static struct virtio_device_id id_table[] = {
 900         { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
 901         { 0 },
 902 };
 903
 904 static unsigned int features[] = {
 905         VIRTIO_SCSI_F_HOTPLUG,
 906         VIRTIO_SCSI_F_CHANGE,
 907 #ifdef CONFIG_BLK_DEV_INTEGRITY
 908         VIRTIO_SCSI_F_T10_PI,
 909 #endif
 910 };
 911
 912 static struct virtio_driver virtio_scsi_driver = {
 913         .feature_table = features,
 914         .feature_table_size = ARRAY_SIZE(features),
 915         .driver.name = KBUILD_MODNAME,
 916         .driver.owner = THIS_MODULE,
 917         .id_table = id_table,
 918         .probe = virtscsi_probe,
 919 #ifdef CONFIG_PM_SLEEP
 920         .freeze = virtscsi_freeze,
 921         .restore = virtscsi_restore,
 922 #endif
 923         .remove = virtscsi_remove,
 924 };
 925
 926 static int __init init(void)
 927 {
 928         int ret = -ENOMEM;
 929
 930         virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
 931         if (!virtscsi_cmd_cache) {
 932                 pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
 933                 goto error;
 934         }
 935
 936
 937         virtscsi_cmd_pool =
 938                 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
 939                                          virtscsi_cmd_cache);
 940         if (!virtscsi_cmd_pool) {
 941                 pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
 942                 goto error;
 943         }
 944         ret = register_virtio_driver(&virtio_scsi_driver);
 945         if (ret < 0)
 946                 goto error;
 947
 948         return 0;
 949
 950 error:
 951         if (virtscsi_cmd_pool) {
 952                 mempool_destroy(virtscsi_cmd_pool);
 953                 virtscsi_cmd_pool = NULL;
 954         }
 955         if (virtscsi_cmd_cache) {
 956                 kmem_cache_destroy(virtscsi_cmd_cache);
 957                 virtscsi_cmd_cache = NULL;
 958         }
 959         return ret;
 960 }
 961
 962 static void __exit fini(void)
 963 {
 964         unregister_virtio_driver(&virtio_scsi_driver);
 965         mempool_destroy(virtscsi_cmd_pool);
 966         kmem_cache_destroy(virtscsi_cmd_cache);
 967 }
 968 module_init(init);
 969 module_exit(fini);
 970
 971 MODULE_DEVICE_TABLE(virtio, id_table);
 972 MODULE_DESCRIPTION("Virtio SCSI HBA driver");
 973 MODULE_LICENSE("GPL");