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 #include "sd.h"
  34
  35 #define VIRTIO_SCSI_MEMPOOL_SZ 64
  36 #define VIRTIO_SCSI_EVENT_LEN 8
  37 #define VIRTIO_SCSI_VQ_BASE 2
  38
  39 /* Command queue element */
  40 struct virtio_scsi_cmd {
  41         struct scsi_cmnd *sc;
  42         struct completion *comp;
  43         union {
  44                 struct virtio_scsi_cmd_req       cmd;
  45                 struct virtio_scsi_cmd_req_pi    cmd_pi;
  46                 struct virtio_scsi_ctrl_tmf_req  tmf;
  47                 struct virtio_scsi_ctrl_an_req   an;
  48         } req;
  49         union {
  50                 struct virtio_scsi_cmd_resp      cmd;
  51                 struct virtio_scsi_ctrl_tmf_resp tmf;
  52                 struct virtio_scsi_ctrl_an_resp  an;
  53                 struct virtio_scsi_event         evt;
  54         } resp;
  55 } ____cacheline_aligned_in_smp;
  56
  57 struct virtio_scsi_event_node {
  58         struct virtio_scsi *vscsi;
  59         struct virtio_scsi_event event;
  60         struct work_struct work;
  61 };
  62
  63 struct virtio_scsi_vq {
  64         /* Protects vq */
  65         spinlock_t vq_lock;
  66
  67         struct virtqueue *vq;
  68 };
  69
  70 /* Driver instance state */
  71 struct virtio_scsi {
  72         struct virtio_device *vdev;
  73
  74         /* Get some buffers ready for event vq */
  75         struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN];
  76
  77         u32 num_queues;
  78
  79         struct hlist_node node;
  80
  81         /* Protected by event_vq lock */
  82         bool stop_events;
  83
  84         struct virtio_scsi_vq ctrl_vq;
  85         struct virtio_scsi_vq event_vq;
  86         struct virtio_scsi_vq req_vqs[];
  87 };
  88
  89 static struct kmem_cache *virtscsi_cmd_cache;
  90 static mempool_t *virtscsi_cmd_pool;
  91
  92 static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
  93 {
  94         return vdev->priv;
  95 }
  96
  97 static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
  98 {
  99         if (resid)
 100                 scsi_set_resid(sc, resid);
 101 }
 102
 103 /**
 104  * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
 105  *
 106  * Called with vq_lock held.
 107  */
 108 static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
 109 {
 110         struct virtio_scsi_cmd *cmd = buf;
 111         struct scsi_cmnd *sc = cmd->sc;
 112         struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
 113
 114         dev_dbg(&sc->device->sdev_gendev,
 115                 "cmd %p response %u status %#02x sense_len %u\n",
 116                 sc, resp->response, resp->status, resp->sense_len);
 117
 118         sc->result = resp->status;
 119         virtscsi_compute_resid(sc, virtio32_to_cpu(vscsi->vdev, resp->resid));
 120         switch (resp->response) {
 121         case VIRTIO_SCSI_S_OK:
 122                 set_host_byte(sc, DID_OK);
 123                 break;
 124         case VIRTIO_SCSI_S_OVERRUN:
 125                 set_host_byte(sc, DID_ERROR);
 126                 break;
 127         case VIRTIO_SCSI_S_ABORTED:
 128                 set_host_byte(sc, DID_ABORT);
 129                 break;
 130         case VIRTIO_SCSI_S_BAD_TARGET:
 131                 set_host_byte(sc, DID_BAD_TARGET);
 132                 break;
 133         case VIRTIO_SCSI_S_RESET:
 134                 set_host_byte(sc, DID_RESET);
 135                 break;
 136         case VIRTIO_SCSI_S_BUSY:
 137                 set_host_byte(sc, DID_BUS_BUSY);
 138                 break;
 139         case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
 140                 set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
 141                 break;
 142         case VIRTIO_SCSI_S_TARGET_FAILURE:
 143                 set_host_byte(sc, DID_TARGET_FAILURE);
 144                 break;
 145         case VIRTIO_SCSI_S_NEXUS_FAILURE:
 146                 set_host_byte(sc, DID_NEXUS_FAILURE);
 147                 break;
 148         default:
 149                 scmd_printk(KERN_WARNING, sc, "Unknown response %d",
 150                             resp->response);
 151                 /* fall through */
 152         case VIRTIO_SCSI_S_FAILURE:
 153                 set_host_byte(sc, DID_ERROR);
 154                 break;
 155         }
 156
 157         WARN_ON(virtio32_to_cpu(vscsi->vdev, resp->sense_len) >
 158                 VIRTIO_SCSI_SENSE_SIZE);
 159         if (sc->sense_buffer) {
 160                 memcpy(sc->sense_buffer, resp->sense,
 161                        min_t(u32,
 162                              virtio32_to_cpu(vscsi->vdev, resp->sense_len),
 163                              VIRTIO_SCSI_SENSE_SIZE));
 164                 if (resp->sense_len)
 165                         set_driver_byte(sc, DRIVER_SENSE);
 166         }
 167
 168         sc->scsi_done(sc);
 169 }
 170
 171 static void virtscsi_vq_done(struct virtio_scsi *vscsi,
 172                              struct virtio_scsi_vq *virtscsi_vq,
 173                              void (*fn)(struct virtio_scsi *vscsi, void *buf))
 174 {
 175         void *buf;
 176         unsigned int len;
 177         unsigned long flags;
 178         struct virtqueue *vq = virtscsi_vq->vq;
 179
 180         spin_lock_irqsave(&virtscsi_vq->vq_lock, flags);
 181         do {
 182                 virtqueue_disable_cb(vq);
 183                 while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
 184                         fn(vscsi, buf);
 185
 186                 if (unlikely(virtqueue_is_broken(vq)))
 187                         break;
 188         } while (!virtqueue_enable_cb(vq));
 189         spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
 190 }
 191
 192 static void virtscsi_req_done(struct virtqueue *vq)
 193 {
 194         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 195         struct virtio_scsi *vscsi = shost_priv(sh);
 196         int index = vq->index - VIRTIO_SCSI_VQ_BASE;
 197         struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index];
 198
 199         virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd);
 200 };
 201
 202 static void virtscsi_poll_requests(struct virtio_scsi *vscsi)
 203 {
 204         int i, num_vqs;
 205
 206         num_vqs = vscsi->num_queues;
 207         for (i = 0; i < num_vqs; i++)
 208                 virtscsi_vq_done(vscsi, &vscsi->req_vqs[i],
 209                                  virtscsi_complete_cmd);
 210 }
 211
 212 static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)
 213 {
 214         struct virtio_scsi_cmd *cmd = buf;
 215
 216         if (cmd->comp)
 217                 complete(cmd->comp);
 218 }
 219
 220 static void virtscsi_ctrl_done(struct virtqueue *vq)
 221 {
 222         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 223         struct virtio_scsi *vscsi = shost_priv(sh);
 224
 225         virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free);
 226 };
 227
 228 static void virtscsi_handle_event(struct work_struct *work);
 229
 230 static int virtscsi_kick_event(struct virtio_scsi *vscsi,
 231                                struct virtio_scsi_event_node *event_node)
 232 {
 233         int err;
 234         struct scatterlist sg;
 235         unsigned long flags;
 236
 237         INIT_WORK(&event_node->work, virtscsi_handle_event);
 238         sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
 239
 240         spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
 241
 242         err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node,
 243                                   GFP_ATOMIC);
 244         if (!err)
 245                 virtqueue_kick(vscsi->event_vq.vq);
 246
 247         spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
 248
 249         return err;
 250 }
 251
 252 static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
 253 {
 254         int i;
 255
 256         for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
 257                 vscsi->event_list[i].vscsi = vscsi;
 258                 virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
 259         }
 260
 261         return 0;
 262 }
 263
 264 static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
 265 {
 266         int i;
 267
 268         /* Stop scheduling work before calling cancel_work_sync.  */
 269         spin_lock_irq(&vscsi->event_vq.vq_lock);
 270         vscsi->stop_events = true;
 271         spin_unlock_irq(&vscsi->event_vq.vq_lock);
 272
 273         for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
 274                 cancel_work_sync(&vscsi->event_list[i].work);
 275 }
 276
 277 static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
 278                                             struct virtio_scsi_event *event)
 279 {
 280         struct scsi_device *sdev;
 281         struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 282         unsigned int target = event->lun[1];
 283         unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 284
 285         switch (virtio32_to_cpu(vscsi->vdev, event->reason)) {
 286         case VIRTIO_SCSI_EVT_RESET_RESCAN:
 287                 scsi_add_device(shost, 0, target, lun);
 288                 break;
 289         case VIRTIO_SCSI_EVT_RESET_REMOVED:
 290                 sdev = scsi_device_lookup(shost, 0, target, lun);
 291                 if (sdev) {
 292                         scsi_remove_device(sdev);
 293                         scsi_device_put(sdev);
 294                 } else {
 295                         pr_err("SCSI device %d 0 %d %d not found\n",
 296                                 shost->host_no, target, lun);
 297                 }
 298                 break;
 299         default:
 300                 pr_info("Unsupport virtio scsi event reason %x\n", event->reason);
 301         }
 302 }
 303
 304 static void virtscsi_handle_param_change(struct virtio_scsi *vscsi,
 305                                          struct virtio_scsi_event *event)
 306 {
 307         struct scsi_device *sdev;
 308         struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 309         unsigned int target = event->lun[1];
 310         unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 311         u8 asc = virtio32_to_cpu(vscsi->vdev, event->reason) & 255;
 312         u8 ascq = virtio32_to_cpu(vscsi->vdev, event->reason) >> 8;
 313
 314         sdev = scsi_device_lookup(shost, 0, target, lun);
 315         if (!sdev) {
 316                 pr_err("SCSI device %d 0 %d %d not found\n",
 317                         shost->host_no, target, lun);
 318                 return;
 319         }
 320
 321         /* Handle "Parameters changed", "Mode parameters changed", and
 322            "Capacity data has changed".  */
 323         if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
 324                 scsi_rescan_device(&sdev->sdev_gendev);
 325
 326         scsi_device_put(sdev);
 327 }
 328
 329 static void virtscsi_rescan_hotunplug(struct virtio_scsi *vscsi)
 330 {
 331         struct scsi_device *sdev;
 332         struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 333         unsigned char scsi_cmd[MAX_COMMAND_SIZE];
 334         int result, inquiry_len, inq_result_len = 256;
 335         char *inq_result = kmalloc(inq_result_len, GFP_KERNEL);
 336
 337         shost_for_each_device(sdev, shost) {
 338                 inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
 339
 340                 memset(scsi_cmd, 0, sizeof(scsi_cmd));
 341                 scsi_cmd[0] = INQUIRY;
 342                 scsi_cmd[4] = (unsigned char) inquiry_len;
 343
 344                 memset(inq_result, 0, inq_result_len);
 345
 346                 result = scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE,
 347                                           inq_result, inquiry_len, NULL,
 348                                           SD_TIMEOUT, SD_MAX_RETRIES, NULL);
 349
 350                 if (result == 0 && inq_result[0] >> 5) {
 351                         /* PQ indicates the LUN is not attached */
 352                         scsi_remove_device(sdev);
 353                 }
 354         }
 355
 356         kfree(inq_result);
 357 }
 358
 359 static void virtscsi_handle_event(struct work_struct *work)
 360 {
 361         struct virtio_scsi_event_node *event_node =
 362                 container_of(work, struct virtio_scsi_event_node, work);
 363         struct virtio_scsi *vscsi = event_node->vscsi;
 364         struct virtio_scsi_event *event = &event_node->event;
 365
 366         if (event->event &
 367             cpu_to_virtio32(vscsi->vdev, VIRTIO_SCSI_T_EVENTS_MISSED)) {
 368                 event->event &= ~cpu_to_virtio32(vscsi->vdev,
 369                                                    VIRTIO_SCSI_T_EVENTS_MISSED);
 370                 virtscsi_rescan_hotunplug(vscsi);
 371                 scsi_scan_host(virtio_scsi_host(vscsi->vdev));
 372         }
 373
 374         switch (virtio32_to_cpu(vscsi->vdev, event->event)) {
 375         case VIRTIO_SCSI_T_NO_EVENT:
 376                 break;
 377         case VIRTIO_SCSI_T_TRANSPORT_RESET:
 378                 virtscsi_handle_transport_reset(vscsi, event);
 379                 break;
 380         case VIRTIO_SCSI_T_PARAM_CHANGE:
 381                 virtscsi_handle_param_change(vscsi, event);
 382                 break;
 383         default:
 384                 pr_err("Unsupport virtio scsi event %x\n", event->event);
 385         }
 386         virtscsi_kick_event(vscsi, event_node);
 387 }
 388
 389 static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf)
 390 {
 391         struct virtio_scsi_event_node *event_node = buf;
 392
 393         if (!vscsi->stop_events)
 394                 queue_work(system_freezable_wq, &event_node->work);
 395 }
 396
 397 static void virtscsi_event_done(struct virtqueue *vq)
 398 {
 399         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 400         struct virtio_scsi *vscsi = shost_priv(sh);
 401
 402         virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event);
 403 };
 404
 405 static int __virtscsi_add_cmd(struct virtqueue *vq,
 406                             struct virtio_scsi_cmd *cmd,
 407                             size_t req_size, size_t resp_size)
 408 {
 409         struct scsi_cmnd *sc = cmd->sc;
 410         struct scatterlist *sgs[6], req, resp;
 411         struct sg_table *out, *in;
 412         unsigned out_num = 0, in_num = 0;
 413
 414         out = in = NULL;
 415
 416         if (sc && sc->sc_data_direction != DMA_NONE) {
 417                 if (sc->sc_data_direction != DMA_FROM_DEVICE)
 418                         out = &sc->sdb.table;
 419                 if (sc->sc_data_direction != DMA_TO_DEVICE)
 420                         in = &sc->sdb.table;
 421         }
 422
 423         /* Request header.  */
 424         sg_init_one(&req, &cmd->req, req_size);
 425         sgs[out_num++] = &req;
 426
 427         /* Data-out buffer.  */
 428         if (out) {
 429                 /* Place WRITE protection SGLs before Data OUT payload */
 430                 if (scsi_prot_sg_count(sc))
 431                         sgs[out_num++] = scsi_prot_sglist(sc);
 432                 sgs[out_num++] = out->sgl;
 433         }
 434
 435         /* Response header.  */
 436         sg_init_one(&resp, &cmd->resp, resp_size);
 437         sgs[out_num + in_num++] = &resp;
 438
 439         /* Data-in buffer */
 440         if (in) {
 441                 /* Place READ protection SGLs before Data IN payload */
 442                 if (scsi_prot_sg_count(sc))
 443                         sgs[out_num + in_num++] = scsi_prot_sglist(sc);
 444                 sgs[out_num + in_num++] = in->sgl;
 445         }
 446
 447         return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC);
 448 }
 449
 450 static void virtscsi_kick_vq(struct virtio_scsi_vq *vq)
 451 {
 452         bool needs_kick;
 453         unsigned long flags;
 454
 455         spin_lock_irqsave(&vq->vq_lock, flags);
 456         needs_kick = virtqueue_kick_prepare(vq->vq);
 457         spin_unlock_irqrestore(&vq->vq_lock, flags);
 458
 459         if (needs_kick)
 460                 virtqueue_notify(vq->vq);
 461 }
 462
 463 /**
 464  * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue, optionally kick it
 465  * @vq          : the struct virtqueue we're talking about
 466  * @cmd         : command structure
 467  * @req_size    : size of the request buffer
 468  * @resp_size   : size of the response buffer
 469  * @kick        : whether to kick the virtqueue immediately
 470  */
 471 static int virtscsi_add_cmd(struct virtio_scsi_vq *vq,
 472                              struct virtio_scsi_cmd *cmd,
 473                              size_t req_size, size_t resp_size,
 474                              bool kick)
 475 {
 476         unsigned long flags;
 477         int err;
 478         bool needs_kick = false;
 479
 480         spin_lock_irqsave(&vq->vq_lock, flags);
 481         err = __virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size);
 482         if (!err && kick)
 483                 needs_kick = virtqueue_kick_prepare(vq->vq);
 484
 485         spin_unlock_irqrestore(&vq->vq_lock, flags);
 486
 487         if (needs_kick)
 488                 virtqueue_notify(vq->vq);
 489         return err;
 490 }
 491
 492 static void virtio_scsi_init_hdr(struct virtio_device *vdev,
 493                                  struct virtio_scsi_cmd_req *cmd,
 494                                  struct scsi_cmnd *sc)
 495 {
 496         cmd->lun[0] = 1;
 497         cmd->lun[1] = sc->device->id;
 498         cmd->lun[2] = (sc->device->lun >> 8) | 0x40;
 499         cmd->lun[3] = sc->device->lun & 0xff;
 500         cmd->tag = cpu_to_virtio64(vdev, (unsigned long)sc);
 501         cmd->task_attr = VIRTIO_SCSI_S_SIMPLE;
 502         cmd->prio = 0;
 503         cmd->crn = 0;
 504 }
 505
 506 #ifdef CONFIG_BLK_DEV_INTEGRITY
 507 static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev,
 508                                     struct virtio_scsi_cmd_req_pi *cmd_pi,
 509                                     struct scsi_cmnd *sc)
 510 {
 511         struct request *rq = sc->request;
 512         struct blk_integrity *bi;
 513
 514         virtio_scsi_init_hdr(vdev, (struct virtio_scsi_cmd_req *)cmd_pi, sc);
 515
 516         if (!rq || !scsi_prot_sg_count(sc))
 517                 return;
 518
 519         bi = blk_get_integrity(rq->rq_disk);
 520
 521         if (sc->sc_data_direction == DMA_TO_DEVICE)
 522                 cmd_pi->pi_bytesout = cpu_to_virtio32(vdev,
 523                                                       bio_integrity_bytes(bi,
 524                                                         blk_rq_sectors(rq)));
 525         else if (sc->sc_data_direction == DMA_FROM_DEVICE)
 526                 cmd_pi->pi_bytesin = cpu_to_virtio32(vdev,
 527                                                      bio_integrity_bytes(bi,
 528                                                         blk_rq_sectors(rq)));
 529 }
 530 #endif
 531
 532 static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi,
 533                                                   struct scsi_cmnd *sc)
 534 {
 535         u32 tag = blk_mq_unique_tag(sc->request);
 536         u16 hwq = blk_mq_unique_tag_to_hwq(tag);
 537
 538         return &vscsi->req_vqs[hwq];
 539 }
 540
 541 static int virtscsi_queuecommand(struct Scsi_Host *shost,
 542                                  struct scsi_cmnd *sc)
 543 {
 544         struct virtio_scsi *vscsi = shost_priv(shost);
 545         struct virtio_scsi_vq *req_vq = virtscsi_pick_vq_mq(vscsi, sc);
 546         struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
 547         bool kick;
 548         unsigned long flags;
 549         int req_size;
 550         int ret;
 551
 552         BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
 553
 554         /* TODO: check feature bit and fail if unsupported?  */
 555         BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
 556
 557         dev_dbg(&sc->device->sdev_gendev,
 558                 "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
 559
 560         cmd->sc = sc;
 561
 562         BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
 563
 564 #ifdef CONFIG_BLK_DEV_INTEGRITY
 565         if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) {
 566                 virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, sc);
 567                 memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len);
 568                 req_size = sizeof(cmd->req.cmd_pi);
 569         } else
 570 #endif
 571         {
 572                 virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, sc);
 573                 memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
 574                 req_size = sizeof(cmd->req.cmd);
 575         }
 576
 577         kick = (sc->flags & SCMD_LAST) != 0;
 578         ret = virtscsi_add_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd), kick);
 579         if (ret == -EIO) {
 580                 cmd->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
 581                 spin_lock_irqsave(&req_vq->vq_lock, flags);
 582                 virtscsi_complete_cmd(vscsi, cmd);
 583                 spin_unlock_irqrestore(&req_vq->vq_lock, flags);
 584         } else if (ret != 0) {
 585                 return SCSI_MLQUEUE_HOST_BUSY;
 586         }
 587         return 0;
 588 }
 589
 590 static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
 591 {
 592         DECLARE_COMPLETION_ONSTACK(comp);
 593         int ret = FAILED;
 594
 595         cmd->comp = &comp;
 596         if (virtscsi_add_cmd(&vscsi->ctrl_vq, cmd,
 597                               sizeof cmd->req.tmf, sizeof cmd->resp.tmf, true) < 0)
 598                 goto out;
 599
 600         wait_for_completion(&comp);
 601         if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
 602             cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
 603                 ret = SUCCESS;
 604
 605         /*
 606          * The spec guarantees that all requests related to the TMF have
 607          * been completed, but the callback might not have run yet if
 608          * we're using independent interrupts (e.g. MSI).  Poll the
 609          * virtqueues once.
 610          *
 611          * In the abort case, sc->scsi_done will do nothing, because
 612          * the block layer must have detected a timeout and as a result
 613          * REQ_ATOM_COMPLETE has been set.
 614          */
 615         virtscsi_poll_requests(vscsi);
 616
 617 out:
 618         mempool_free(cmd, virtscsi_cmd_pool);
 619         return ret;
 620 }
 621
 622 static int virtscsi_device_reset(struct scsi_cmnd *sc)
 623 {
 624         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 625         struct virtio_scsi_cmd *cmd;
 626
 627         sdev_printk(KERN_INFO, sc->device, "device reset\n");
 628         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 629         if (!cmd)
 630                 return FAILED;
 631
 632         memset(cmd, 0, sizeof(*cmd));
 633         cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 634                 .type = VIRTIO_SCSI_T_TMF,
 635                 .subtype = cpu_to_virtio32(vscsi->vdev,
 636                                              VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET),
 637                 .lun[0] = 1,
 638                 .lun[1] = sc->device->id,
 639                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 640                 .lun[3] = sc->device->lun & 0xff,
 641         };
 642         return virtscsi_tmf(vscsi, cmd);
 643 }
 644
 645 static int virtscsi_device_alloc(struct scsi_device *sdevice)
 646 {
 647         /*
 648          * Passed through SCSI targets (e.g. with qemu's 'scsi-block')
 649          * may have transfer limits which come from the host SCSI
 650          * controller or something on the host side other than the
 651          * target itself.
 652          *
 653          * To make this work properly, the hypervisor can adjust the
 654          * target's VPD information to advertise these limits.  But
 655          * for that to work, the guest has to look at the VPD pages,
 656          * which we won't do by default if it is an SPC-2 device, even
 657          * if it does actually support it.
 658          *
 659          * So, set the blist to always try to read the VPD pages.
 660          */
 661         sdevice->sdev_bflags = BLIST_TRY_VPD_PAGES;
 662
 663         return 0;
 664 }
 665
 666
 667 /**
 668  * virtscsi_change_queue_depth() - Change a virtscsi target's queue depth
 669  * @sdev:       Virtscsi target whose queue depth to change
 670  * @qdepth:     New queue depth
 671  */
 672 static int virtscsi_change_queue_depth(struct scsi_device *sdev, int qdepth)
 673 {
 674         struct Scsi_Host *shost = sdev->host;
 675         int max_depth = shost->cmd_per_lun;
 676
 677         return scsi_change_queue_depth(sdev, min(max_depth, qdepth));
 678 }
 679
 680 static int virtscsi_abort(struct scsi_cmnd *sc)
 681 {
 682         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 683         struct virtio_scsi_cmd *cmd;
 684
 685         scmd_printk(KERN_INFO, sc, "abort\n");
 686         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 687         if (!cmd)
 688                 return FAILED;
 689
 690         memset(cmd, 0, sizeof(*cmd));
 691         cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 692                 .type = VIRTIO_SCSI_T_TMF,
 693                 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
 694                 .lun[0] = 1,
 695                 .lun[1] = sc->device->id,
 696                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 697                 .lun[3] = sc->device->lun & 0xff,
 698                 .tag = cpu_to_virtio64(vscsi->vdev, (unsigned long)sc),
 699         };
 700         return virtscsi_tmf(vscsi, cmd);
 701 }
 702
 703 static int virtscsi_map_queues(struct Scsi_Host *shost)
 704 {
 705         struct virtio_scsi *vscsi = shost_priv(shost);
 706         struct blk_mq_queue_map *qmap = &shost->tag_set.map[HCTX_TYPE_DEFAULT];
 707
 708         return blk_mq_virtio_map_queues(qmap, vscsi->vdev, 2);
 709 }
 710
 711 static void virtscsi_commit_rqs(struct Scsi_Host *shost, u16 hwq)
 712 {
 713         struct virtio_scsi *vscsi = shost_priv(shost);
 714
 715         virtscsi_kick_vq(&vscsi->req_vqs[hwq]);
 716 }
 717
 718 /*
 719  * The host guarantees to respond to each command, although I/O
 720  * latencies might be higher than on bare metal.  Reset the timer
 721  * unconditionally to give the host a chance to perform EH.
 722  */
 723 static enum blk_eh_timer_return virtscsi_eh_timed_out(struct scsi_cmnd *scmnd)
 724 {
 725         return BLK_EH_RESET_TIMER;
 726 }
 727
 728 static struct scsi_host_template virtscsi_host_template = {
 729         .module = THIS_MODULE,
 730         .name = "Virtio SCSI HBA",
 731         .proc_name = "virtio_scsi",
 732         .this_id = -1,
 733         .cmd_size = sizeof(struct virtio_scsi_cmd),
 734         .queuecommand = virtscsi_queuecommand,
 735         .commit_rqs = virtscsi_commit_rqs,
 736         .change_queue_depth = virtscsi_change_queue_depth,
 737         .eh_abort_handler = virtscsi_abort,
 738         .eh_device_reset_handler = virtscsi_device_reset,
 739         .eh_timed_out = virtscsi_eh_timed_out,
 740         .slave_alloc = virtscsi_device_alloc,
 741
 742         .dma_boundary = UINT_MAX,
 743         .map_queues = virtscsi_map_queues,
 744         .track_queue_depth = 1,
 745         .force_blk_mq = 1,
 746 };
 747
 748 #define virtscsi_config_get(vdev, fld) \
 749         ({ \
 750                 typeof(((struct virtio_scsi_config *)0)->fld) __val; \
 751                 virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \
 752                 __val; \
 753         })
 754
 755 #define virtscsi_config_set(vdev, fld, val) \
 756         do { \
 757                 typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
 758                 virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \
 759         } while(0)
 760
 761 static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
 762                              struct virtqueue *vq)
 763 {
 764         spin_lock_init(&virtscsi_vq->vq_lock);
 765         virtscsi_vq->vq = vq;
 766 }
 767
 768 static void virtscsi_remove_vqs(struct virtio_device *vdev)
 769 {
 770         /* Stop all the virtqueues. */
 771         vdev->config->reset(vdev);
 772         vdev->config->del_vqs(vdev);
 773 }
 774
 775 static int virtscsi_init(struct virtio_device *vdev,
 776                          struct virtio_scsi *vscsi)
 777 {
 778         int err;
 779         u32 i;
 780         u32 num_vqs;
 781         vq_callback_t **callbacks;
 782         const char **names;
 783         struct virtqueue **vqs;
 784         struct irq_affinity desc = { .pre_vectors = 2 };
 785
 786         num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;
 787         vqs = kmalloc_array(num_vqs, sizeof(struct virtqueue *), GFP_KERNEL);
 788         callbacks = kmalloc_array(num_vqs, sizeof(vq_callback_t *),
 789                                   GFP_KERNEL);
 790         names = kmalloc_array(num_vqs, sizeof(char *), GFP_KERNEL);
 791
 792         if (!callbacks || !vqs || !names) {
 793                 err = -ENOMEM;
 794                 goto out;
 795         }
 796
 797         callbacks[0] = virtscsi_ctrl_done;
 798         callbacks[1] = virtscsi_event_done;
 799         names[0] = "control";
 800         names[1] = "event";
 801         for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) {
 802                 callbacks[i] = virtscsi_req_done;
 803                 names[i] = "request";
 804         }
 805
 806         /* Discover virtqueues and write information to configuration.  */
 807         err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc);
 808         if (err)
 809                 goto out;
 810
 811         virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
 812         virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
 813         for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
 814                 virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
 815                                  vqs[i]);
 816
 817         virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
 818         virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
 819
 820         err = 0;
 821
 822 out:
 823         kfree(names);
 824         kfree(callbacks);
 825         kfree(vqs);
 826         if (err)
 827                 virtscsi_remove_vqs(vdev);
 828         return err;
 829 }
 830
 831 static int virtscsi_probe(struct virtio_device *vdev)
 832 {
 833         struct Scsi_Host *shost;
 834         struct virtio_scsi *vscsi;
 835         int err;
 836         u32 sg_elems, num_targets;
 837         u32 cmd_per_lun;
 838         u32 num_queues;
 839
 840         if (!vdev->config->get) {
 841                 dev_err(&vdev->dev, "%s failure: config access disabled\n",
 842                         __func__);
 843                 return -EINVAL;
 844         }
 845
 846         /* We need to know how many queues before we allocate. */
 847         num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
 848         num_queues = min_t(unsigned int, nr_cpu_ids, num_queues);
 849
 850         num_targets = virtscsi_config_get(vdev, max_target) + 1;
 851
 852         shost = scsi_host_alloc(&virtscsi_host_template,
 853                                 struct_size(vscsi, req_vqs, num_queues));
 854         if (!shost)
 855                 return -ENOMEM;
 856
 857         sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
 858         shost->sg_tablesize = sg_elems;
 859         vscsi = shost_priv(shost);
 860         vscsi->vdev = vdev;
 861         vscsi->num_queues = num_queues;
 862         vdev->priv = shost;
 863
 864         err = virtscsi_init(vdev, vscsi);
 865         if (err)
 866                 goto virtscsi_init_failed;
 867
 868         shost->can_queue = virtqueue_get_vring_size(vscsi->req_vqs[0].vq);
 869
 870         cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
 871         shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
 872         shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
 873
 874         /* LUNs > 256 are reported with format 1, so they go in the range
 875          * 16640-32767.
 876          */
 877         shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
 878         shost->max_id = num_targets;
 879         shost->max_channel = 0;
 880         shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
 881         shost->nr_hw_queues = num_queues;
 882
 883 #ifdef CONFIG_BLK_DEV_INTEGRITY
 884         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
 885                 int host_prot;
 886
 887                 host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
 888                             SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
 889                             SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
 890
 891                 scsi_host_set_prot(shost, host_prot);
 892                 scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC);
 893         }
 894 #endif
 895
 896         err = scsi_add_host(shost, &vdev->dev);
 897         if (err)
 898                 goto scsi_add_host_failed;
 899
 900         virtio_device_ready(vdev);
 901
 902         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 903                 virtscsi_kick_event_all(vscsi);
 904
 905         scsi_scan_host(shost);
 906         return 0;
 907
 908 scsi_add_host_failed:
 909         vdev->config->del_vqs(vdev);
 910 virtscsi_init_failed:
 911         scsi_host_put(shost);
 912         return err;
 913 }
 914
 915 static void virtscsi_remove(struct virtio_device *vdev)
 916 {
 917         struct Scsi_Host *shost = virtio_scsi_host(vdev);
 918         struct virtio_scsi *vscsi = shost_priv(shost);
 919
 920         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 921                 virtscsi_cancel_event_work(vscsi);
 922
 923         scsi_remove_host(shost);
 924         virtscsi_remove_vqs(vdev);
 925         scsi_host_put(shost);
 926 }
 927
 928 #ifdef CONFIG_PM_SLEEP
 929 static int virtscsi_freeze(struct virtio_device *vdev)
 930 {
 931         virtscsi_remove_vqs(vdev);
 932         return 0;
 933 }
 934
 935 static int virtscsi_restore(struct virtio_device *vdev)
 936 {
 937         struct Scsi_Host *sh = virtio_scsi_host(vdev);
 938         struct virtio_scsi *vscsi = shost_priv(sh);
 939         int err;
 940
 941         err = virtscsi_init(vdev, vscsi);
 942         if (err)
 943                 return err;
 944
 945         virtio_device_ready(vdev);
 946
 947         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 948                 virtscsi_kick_event_all(vscsi);
 949
 950         return err;
 951 }
 952 #endif
 953
 954 static struct virtio_device_id id_table[] = {
 955         { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
 956         { 0 },
 957 };
 958
 959 static unsigned int features[] = {
 960         VIRTIO_SCSI_F_HOTPLUG,
 961         VIRTIO_SCSI_F_CHANGE,
 962 #ifdef CONFIG_BLK_DEV_INTEGRITY
 963         VIRTIO_SCSI_F_T10_PI,
 964 #endif
 965 };
 966
 967 static struct virtio_driver virtio_scsi_driver = {
 968         .feature_table = features,
 969         .feature_table_size = ARRAY_SIZE(features),
 970         .driver.name = KBUILD_MODNAME,
 971         .driver.owner = THIS_MODULE,
 972         .id_table = id_table,
 973         .probe = virtscsi_probe,
 974 #ifdef CONFIG_PM_SLEEP
 975         .freeze = virtscsi_freeze,
 976         .restore = virtscsi_restore,
 977 #endif
 978         .remove = virtscsi_remove,
 979 };
 980
 981 static int __init init(void)
 982 {
 983         int ret = -ENOMEM;
 984
 985         virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
 986         if (!virtscsi_cmd_cache) {
 987                 pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
 988                 goto error;
 989         }
 990
 991
 992         virtscsi_cmd_pool =
 993                 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
 994                                          virtscsi_cmd_cache);
 995         if (!virtscsi_cmd_pool) {
 996                 pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
 997                 goto error;
 998         }
 999         ret = register_virtio_driver(&virtio_scsi_driver);
1000         if (ret < 0)
1001                 goto error;
1002
1003         return 0;
1004
1005 error:
1006         if (virtscsi_cmd_pool) {
1007                 mempool_destroy(virtscsi_cmd_pool);
1008                 virtscsi_cmd_pool = NULL;
1009         }
1010         if (virtscsi_cmd_cache) {
1011                 kmem_cache_destroy(virtscsi_cmd_cache);
1012                 virtscsi_cmd_cache = NULL;
1013         }
1014         return ret;
1015 }
1016
1017 static void __exit fini(void)
1018 {
1019         unregister_virtio_driver(&virtio_scsi_driver);
1020         mempool_destroy(virtscsi_cmd_pool);
1021         kmem_cache_destroy(virtscsi_cmd_cache);
1022 }
1023 module_init(init);
1024 module_exit(fini);
1025
1026 MODULE_DEVICE_TABLE(virtio, id_table);
1027 MODULE_DESCRIPTION("Virtio SCSI HBA driver");
1028 MODULE_LICENSE("GPL");