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, min(resid, scsi_bufflen(sc)));
 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                 fallthrough;
 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 (resp->sense_len) {
 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         }
 165
 166         sc->scsi_done(sc);
 167 }
 168
 169 static void virtscsi_vq_done(struct virtio_scsi *vscsi,
 170                              struct virtio_scsi_vq *virtscsi_vq,
 171                              void (*fn)(struct virtio_scsi *vscsi, void *buf))
 172 {
 173         void *buf;
 174         unsigned int len;
 175         unsigned long flags;
 176         struct virtqueue *vq = virtscsi_vq->vq;
 177
 178         spin_lock_irqsave(&virtscsi_vq->vq_lock, flags);
 179         do {
 180                 virtqueue_disable_cb(vq);
 181                 while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
 182                         fn(vscsi, buf);
 183
 184                 if (unlikely(virtqueue_is_broken(vq)))
 185                         break;
 186         } while (!virtqueue_enable_cb(vq));
 187         spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
 188 }
 189
 190 static void virtscsi_req_done(struct virtqueue *vq)
 191 {
 192         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 193         struct virtio_scsi *vscsi = shost_priv(sh);
 194         int index = vq->index - VIRTIO_SCSI_VQ_BASE;
 195         struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index];
 196
 197         virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd);
 198 };
 199
 200 static void virtscsi_poll_requests(struct virtio_scsi *vscsi)
 201 {
 202         int i, num_vqs;
 203
 204         num_vqs = vscsi->num_queues;
 205         for (i = 0; i < num_vqs; i++)
 206                 virtscsi_vq_done(vscsi, &vscsi->req_vqs[i],
 207                                  virtscsi_complete_cmd);
 208 }
 209
 210 static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)
 211 {
 212         struct virtio_scsi_cmd *cmd = buf;
 213
 214         if (cmd->comp)
 215                 complete(cmd->comp);
 216 }
 217
 218 static void virtscsi_ctrl_done(struct virtqueue *vq)
 219 {
 220         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 221         struct virtio_scsi *vscsi = shost_priv(sh);
 222
 223         virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free);
 224 };
 225
 226 static void virtscsi_handle_event(struct work_struct *work);
 227
 228 static int virtscsi_kick_event(struct virtio_scsi *vscsi,
 229                                struct virtio_scsi_event_node *event_node)
 230 {
 231         int err;
 232         struct scatterlist sg;
 233         unsigned long flags;
 234
 235         INIT_WORK(&event_node->work, virtscsi_handle_event);
 236         sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
 237
 238         spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
 239
 240         err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node,
 241                                   GFP_ATOMIC);
 242         if (!err)
 243                 virtqueue_kick(vscsi->event_vq.vq);
 244
 245         spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
 246
 247         return err;
 248 }
 249
 250 static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
 251 {
 252         int i;
 253
 254         for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
 255                 vscsi->event_list[i].vscsi = vscsi;
 256                 virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
 257         }
 258
 259         return 0;
 260 }
 261
 262 static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
 263 {
 264         int i;
 265
 266         /* Stop scheduling work before calling cancel_work_sync.  */
 267         spin_lock_irq(&vscsi->event_vq.vq_lock);
 268         vscsi->stop_events = true;
 269         spin_unlock_irq(&vscsi->event_vq.vq_lock);
 270
 271         for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
 272                 cancel_work_sync(&vscsi->event_list[i].work);
 273 }
 274
 275 static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
 276                                             struct virtio_scsi_event *event)
 277 {
 278         struct scsi_device *sdev;
 279         struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 280         unsigned int target = event->lun[1];
 281         unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 282
 283         switch (virtio32_to_cpu(vscsi->vdev, event->reason)) {
 284         case VIRTIO_SCSI_EVT_RESET_RESCAN:
 285                 if (lun == 0) {
 286                         scsi_scan_target(&shost->shost_gendev, 0, target,
 287                                          SCAN_WILD_CARD, SCSI_SCAN_INITIAL);
 288                 } else {
 289                         scsi_add_device(shost, 0, target, lun);
 290                 }
 291                 break;
 292         case VIRTIO_SCSI_EVT_RESET_REMOVED:
 293                 sdev = scsi_device_lookup(shost, 0, target, lun);
 294                 if (sdev) {
 295                         scsi_remove_device(sdev);
 296                         scsi_device_put(sdev);
 297                 } else {
 298                         pr_err("SCSI device %d 0 %d %d not found\n",
 299                                 shost->host_no, target, lun);
 300                 }
 301                 break;
 302         default:
 303                 pr_info("Unsupported virtio scsi event reason %x\n", event->reason);
 304         }
 305 }
 306
 307 static void virtscsi_handle_param_change(struct virtio_scsi *vscsi,
 308                                          struct virtio_scsi_event *event)
 309 {
 310         struct scsi_device *sdev;
 311         struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 312         unsigned int target = event->lun[1];
 313         unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 314         u8 asc = virtio32_to_cpu(vscsi->vdev, event->reason) & 255;
 315         u8 ascq = virtio32_to_cpu(vscsi->vdev, event->reason) >> 8;
 316
 317         sdev = scsi_device_lookup(shost, 0, target, lun);
 318         if (!sdev) {
 319                 pr_err("SCSI device %d 0 %d %d not found\n",
 320                         shost->host_no, target, lun);
 321                 return;
 322         }
 323
 324         /* Handle "Parameters changed", "Mode parameters changed", and
 325            "Capacity data has changed".  */
 326         if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
 327                 scsi_rescan_device(&sdev->sdev_gendev);
 328
 329         scsi_device_put(sdev);
 330 }
 331
 332 static void virtscsi_rescan_hotunplug(struct virtio_scsi *vscsi)
 333 {
 334         struct scsi_device *sdev;
 335         struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 336         unsigned char scsi_cmd[MAX_COMMAND_SIZE];
 337         int result, inquiry_len, inq_result_len = 256;
 338         char *inq_result = kmalloc(inq_result_len, GFP_KERNEL);
 339
 340         shost_for_each_device(sdev, shost) {
 341                 inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
 342
 343                 memset(scsi_cmd, 0, sizeof(scsi_cmd));
 344                 scsi_cmd[0] = INQUIRY;
 345                 scsi_cmd[4] = (unsigned char) inquiry_len;
 346
 347                 memset(inq_result, 0, inq_result_len);
 348
 349                 result = scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE,
 350                                           inq_result, inquiry_len, NULL,
 351                                           SD_TIMEOUT, SD_MAX_RETRIES, NULL);
 352
 353                 if (result == 0 && inq_result[0] >> 5) {
 354                         /* PQ indicates the LUN is not attached */
 355                         scsi_remove_device(sdev);
 356                 } else if (result > 0 && host_byte(result) == DID_BAD_TARGET) {
 357                         /*
 358                          * If all LUNs of a virtio-scsi device are unplugged
 359                          * it will respond with BAD TARGET on any INQUIRY
 360                          * command.
 361                          * Remove the device in this case as well.
 362                          */
 363                         scsi_remove_device(sdev);
 364                 }
 365         }
 366
 367         kfree(inq_result);
 368 }
 369
 370 static void virtscsi_handle_event(struct work_struct *work)
 371 {
 372         struct virtio_scsi_event_node *event_node =
 373                 container_of(work, struct virtio_scsi_event_node, work);
 374         struct virtio_scsi *vscsi = event_node->vscsi;
 375         struct virtio_scsi_event *event = &event_node->event;
 376
 377         if (event->event &
 378             cpu_to_virtio32(vscsi->vdev, VIRTIO_SCSI_T_EVENTS_MISSED)) {
 379                 event->event &= ~cpu_to_virtio32(vscsi->vdev,
 380                                                    VIRTIO_SCSI_T_EVENTS_MISSED);
 381                 virtscsi_rescan_hotunplug(vscsi);
 382                 scsi_scan_host(virtio_scsi_host(vscsi->vdev));
 383         }
 384
 385         switch (virtio32_to_cpu(vscsi->vdev, event->event)) {
 386         case VIRTIO_SCSI_T_NO_EVENT:
 387                 break;
 388         case VIRTIO_SCSI_T_TRANSPORT_RESET:
 389                 virtscsi_handle_transport_reset(vscsi, event);
 390                 break;
 391         case VIRTIO_SCSI_T_PARAM_CHANGE:
 392                 virtscsi_handle_param_change(vscsi, event);
 393                 break;
 394         default:
 395                 pr_err("Unsupported virtio scsi event %x\n", event->event);
 396         }
 397         virtscsi_kick_event(vscsi, event_node);
 398 }
 399
 400 static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf)
 401 {
 402         struct virtio_scsi_event_node *event_node = buf;
 403
 404         if (!vscsi->stop_events)
 405                 queue_work(system_freezable_wq, &event_node->work);
 406 }
 407
 408 static void virtscsi_event_done(struct virtqueue *vq)
 409 {
 410         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 411         struct virtio_scsi *vscsi = shost_priv(sh);
 412
 413         virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event);
 414 };
 415
 416 static int __virtscsi_add_cmd(struct virtqueue *vq,
 417                             struct virtio_scsi_cmd *cmd,
 418                             size_t req_size, size_t resp_size)
 419 {
 420         struct scsi_cmnd *sc = cmd->sc;
 421         struct scatterlist *sgs[6], req, resp;
 422         struct sg_table *out, *in;
 423         unsigned out_num = 0, in_num = 0;
 424
 425         out = in = NULL;
 426
 427         if (sc && sc->sc_data_direction != DMA_NONE) {
 428                 if (sc->sc_data_direction != DMA_FROM_DEVICE)
 429                         out = &sc->sdb.table;
 430                 if (sc->sc_data_direction != DMA_TO_DEVICE)
 431                         in = &sc->sdb.table;
 432         }
 433
 434         /* Request header.  */
 435         sg_init_one(&req, &cmd->req, req_size);
 436         sgs[out_num++] = &req;
 437
 438         /* Data-out buffer.  */
 439         if (out) {
 440                 /* Place WRITE protection SGLs before Data OUT payload */
 441                 if (scsi_prot_sg_count(sc))
 442                         sgs[out_num++] = scsi_prot_sglist(sc);
 443                 sgs[out_num++] = out->sgl;
 444         }
 445
 446         /* Response header.  */
 447         sg_init_one(&resp, &cmd->resp, resp_size);
 448         sgs[out_num + in_num++] = &resp;
 449
 450         /* Data-in buffer */
 451         if (in) {
 452                 /* Place READ protection SGLs before Data IN payload */
 453                 if (scsi_prot_sg_count(sc))
 454                         sgs[out_num + in_num++] = scsi_prot_sglist(sc);
 455                 sgs[out_num + in_num++] = in->sgl;
 456         }
 457
 458         return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC);
 459 }
 460
 461 static void virtscsi_kick_vq(struct virtio_scsi_vq *vq)
 462 {
 463         bool needs_kick;
 464         unsigned long flags;
 465
 466         spin_lock_irqsave(&vq->vq_lock, flags);
 467         needs_kick = virtqueue_kick_prepare(vq->vq);
 468         spin_unlock_irqrestore(&vq->vq_lock, flags);
 469
 470         if (needs_kick)
 471                 virtqueue_notify(vq->vq);
 472 }
 473
 474 /**
 475  * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue, optionally kick it
 476  * @vq          : the struct virtqueue we're talking about
 477  * @cmd         : command structure
 478  * @req_size    : size of the request buffer
 479  * @resp_size   : size of the response buffer
 480  * @kick        : whether to kick the virtqueue immediately
 481  */
 482 static int virtscsi_add_cmd(struct virtio_scsi_vq *vq,
 483                              struct virtio_scsi_cmd *cmd,
 484                              size_t req_size, size_t resp_size,
 485                              bool kick)
 486 {
 487         unsigned long flags;
 488         int err;
 489         bool needs_kick = false;
 490
 491         spin_lock_irqsave(&vq->vq_lock, flags);
 492         err = __virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size);
 493         if (!err && kick)
 494                 needs_kick = virtqueue_kick_prepare(vq->vq);
 495
 496         spin_unlock_irqrestore(&vq->vq_lock, flags);
 497
 498         if (needs_kick)
 499                 virtqueue_notify(vq->vq);
 500         return err;
 501 }
 502
 503 static void virtio_scsi_init_hdr(struct virtio_device *vdev,
 504                                  struct virtio_scsi_cmd_req *cmd,
 505                                  struct scsi_cmnd *sc)
 506 {
 507         cmd->lun[0] = 1;
 508         cmd->lun[1] = sc->device->id;
 509         cmd->lun[2] = (sc->device->lun >> 8) | 0x40;
 510         cmd->lun[3] = sc->device->lun & 0xff;
 511         cmd->tag = cpu_to_virtio64(vdev, (unsigned long)sc);
 512         cmd->task_attr = VIRTIO_SCSI_S_SIMPLE;
 513         cmd->prio = 0;
 514         cmd->crn = 0;
 515 }
 516
 517 #ifdef CONFIG_BLK_DEV_INTEGRITY
 518 static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev,
 519                                     struct virtio_scsi_cmd_req_pi *cmd_pi,
 520                                     struct scsi_cmnd *sc)
 521 {
 522         struct request *rq = scsi_cmd_to_rq(sc);
 523         struct blk_integrity *bi;
 524
 525         virtio_scsi_init_hdr(vdev, (struct virtio_scsi_cmd_req *)cmd_pi, sc);
 526
 527         if (!rq || !scsi_prot_sg_count(sc))
 528                 return;
 529
 530         bi = blk_get_integrity(rq->rq_disk);
 531
 532         if (sc->sc_data_direction == DMA_TO_DEVICE)
 533                 cmd_pi->pi_bytesout = cpu_to_virtio32(vdev,
 534                                                       bio_integrity_bytes(bi,
 535                                                         blk_rq_sectors(rq)));
 536         else if (sc->sc_data_direction == DMA_FROM_DEVICE)
 537                 cmd_pi->pi_bytesin = cpu_to_virtio32(vdev,
 538                                                      bio_integrity_bytes(bi,
 539                                                         blk_rq_sectors(rq)));
 540 }
 541 #endif
 542
 543 static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi,
 544                                                   struct scsi_cmnd *sc)
 545 {
 546         u32 tag = blk_mq_unique_tag(scsi_cmd_to_rq(sc));
 547         u16 hwq = blk_mq_unique_tag_to_hwq(tag);
 548
 549         return &vscsi->req_vqs[hwq];
 550 }
 551
 552 static int virtscsi_queuecommand(struct Scsi_Host *shost,
 553                                  struct scsi_cmnd *sc)
 554 {
 555         struct virtio_scsi *vscsi = shost_priv(shost);
 556         struct virtio_scsi_vq *req_vq = virtscsi_pick_vq_mq(vscsi, sc);
 557         struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
 558         bool kick;
 559         unsigned long flags;
 560         int req_size;
 561         int ret;
 562
 563         BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
 564
 565         /* TODO: check feature bit and fail if unsupported?  */
 566         BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
 567
 568         dev_dbg(&sc->device->sdev_gendev,
 569                 "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
 570
 571         cmd->sc = sc;
 572
 573         BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
 574
 575 #ifdef CONFIG_BLK_DEV_INTEGRITY
 576         if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) {
 577                 virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, sc);
 578                 memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len);
 579                 req_size = sizeof(cmd->req.cmd_pi);
 580         } else
 581 #endif
 582         {
 583                 virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, sc);
 584                 memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
 585                 req_size = sizeof(cmd->req.cmd);
 586         }
 587
 588         kick = (sc->flags & SCMD_LAST) != 0;
 589         ret = virtscsi_add_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd), kick);
 590         if (ret == -EIO) {
 591                 cmd->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
 592                 spin_lock_irqsave(&req_vq->vq_lock, flags);
 593                 virtscsi_complete_cmd(vscsi, cmd);
 594                 spin_unlock_irqrestore(&req_vq->vq_lock, flags);
 595         } else if (ret != 0) {
 596                 return SCSI_MLQUEUE_HOST_BUSY;
 597         }
 598         return 0;
 599 }
 600
 601 static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
 602 {
 603         DECLARE_COMPLETION_ONSTACK(comp);
 604         int ret = FAILED;
 605
 606         cmd->comp = &comp;
 607         if (virtscsi_add_cmd(&vscsi->ctrl_vq, cmd,
 608                               sizeof cmd->req.tmf, sizeof cmd->resp.tmf, true) < 0)
 609                 goto out;
 610
 611         wait_for_completion(&comp);
 612         if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
 613             cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
 614                 ret = SUCCESS;
 615
 616         /*
 617          * The spec guarantees that all requests related to the TMF have
 618          * been completed, but the callback might not have run yet if
 619          * we're using independent interrupts (e.g. MSI).  Poll the
 620          * virtqueues once.
 621          *
 622          * In the abort case, sc->scsi_done will do nothing, because
 623          * the block layer must have detected a timeout and as a result
 624          * REQ_ATOM_COMPLETE has been set.
 625          */
 626         virtscsi_poll_requests(vscsi);
 627
 628 out:
 629         mempool_free(cmd, virtscsi_cmd_pool);
 630         return ret;
 631 }
 632
 633 static int virtscsi_device_reset(struct scsi_cmnd *sc)
 634 {
 635         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 636         struct virtio_scsi_cmd *cmd;
 637
 638         sdev_printk(KERN_INFO, sc->device, "device reset\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 = cpu_to_virtio32(vscsi->vdev,
 647                                              VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET),
 648                 .lun[0] = 1,
 649                 .lun[1] = sc->device->id,
 650                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 651                 .lun[3] = sc->device->lun & 0xff,
 652         };
 653         return virtscsi_tmf(vscsi, cmd);
 654 }
 655
 656 static int virtscsi_device_alloc(struct scsi_device *sdevice)
 657 {
 658         /*
 659          * Passed through SCSI targets (e.g. with qemu's 'scsi-block')
 660          * may have transfer limits which come from the host SCSI
 661          * controller or something on the host side other than the
 662          * target itself.
 663          *
 664          * To make this work properly, the hypervisor can adjust the
 665          * target's VPD information to advertise these limits.  But
 666          * for that to work, the guest has to look at the VPD pages,
 667          * which we won't do by default if it is an SPC-2 device, even
 668          * if it does actually support it.
 669          *
 670          * So, set the blist to always try to read the VPD pages.
 671          */
 672         sdevice->sdev_bflags = BLIST_TRY_VPD_PAGES;
 673
 674         return 0;
 675 }
 676
 677
 678 /**
 679  * virtscsi_change_queue_depth() - Change a virtscsi target's queue depth
 680  * @sdev:       Virtscsi target whose queue depth to change
 681  * @qdepth:     New queue depth
 682  */
 683 static int virtscsi_change_queue_depth(struct scsi_device *sdev, int qdepth)
 684 {
 685         struct Scsi_Host *shost = sdev->host;
 686         int max_depth = shost->cmd_per_lun;
 687
 688         return scsi_change_queue_depth(sdev, min(max_depth, qdepth));
 689 }
 690
 691 static int virtscsi_abort(struct scsi_cmnd *sc)
 692 {
 693         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 694         struct virtio_scsi_cmd *cmd;
 695
 696         scmd_printk(KERN_INFO, sc, "abort\n");
 697         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 698         if (!cmd)
 699                 return FAILED;
 700
 701         memset(cmd, 0, sizeof(*cmd));
 702         cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 703                 .type = VIRTIO_SCSI_T_TMF,
 704                 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
 705                 .lun[0] = 1,
 706                 .lun[1] = sc->device->id,
 707                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 708                 .lun[3] = sc->device->lun & 0xff,
 709                 .tag = cpu_to_virtio64(vscsi->vdev, (unsigned long)sc),
 710         };
 711         return virtscsi_tmf(vscsi, cmd);
 712 }
 713
 714 static int virtscsi_map_queues(struct Scsi_Host *shost)
 715 {
 716         struct virtio_scsi *vscsi = shost_priv(shost);
 717         struct blk_mq_queue_map *qmap = &shost->tag_set.map[HCTX_TYPE_DEFAULT];
 718
 719         return blk_mq_virtio_map_queues(qmap, vscsi->vdev, 2);
 720 }
 721
 722 static void virtscsi_commit_rqs(struct Scsi_Host *shost, u16 hwq)
 723 {
 724         struct virtio_scsi *vscsi = shost_priv(shost);
 725
 726         virtscsi_kick_vq(&vscsi->req_vqs[hwq]);
 727 }
 728
 729 /*
 730  * The host guarantees to respond to each command, although I/O
 731  * latencies might be higher than on bare metal.  Reset the timer
 732  * unconditionally to give the host a chance to perform EH.
 733  */
 734 static enum blk_eh_timer_return virtscsi_eh_timed_out(struct scsi_cmnd *scmnd)
 735 {
 736         return BLK_EH_RESET_TIMER;
 737 }
 738
 739 static struct scsi_host_template virtscsi_host_template = {
 740         .module = THIS_MODULE,
 741         .name = "Virtio SCSI HBA",
 742         .proc_name = "virtio_scsi",
 743         .this_id = -1,
 744         .cmd_size = sizeof(struct virtio_scsi_cmd),
 745         .queuecommand = virtscsi_queuecommand,
 746         .commit_rqs = virtscsi_commit_rqs,
 747         .change_queue_depth = virtscsi_change_queue_depth,
 748         .eh_abort_handler = virtscsi_abort,
 749         .eh_device_reset_handler = virtscsi_device_reset,
 750         .eh_timed_out = virtscsi_eh_timed_out,
 751         .slave_alloc = virtscsi_device_alloc,
 752
 753         .dma_boundary = UINT_MAX,
 754         .map_queues = virtscsi_map_queues,
 755         .track_queue_depth = 1,
 756 };
 757
 758 #define virtscsi_config_get(vdev, fld) \
 759         ({ \
 760                 __virtio_native_type(struct virtio_scsi_config, fld) __val; \
 761                 virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \
 762                 __val; \
 763         })
 764
 765 #define virtscsi_config_set(vdev, fld, val) \
 766         do { \
 767                 __virtio_native_type(struct virtio_scsi_config, fld) __val = (val); \
 768                 virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \
 769         } while(0)
 770
 771 static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
 772                              struct virtqueue *vq)
 773 {
 774         spin_lock_init(&virtscsi_vq->vq_lock);
 775         virtscsi_vq->vq = vq;
 776 }
 777
 778 static void virtscsi_remove_vqs(struct virtio_device *vdev)
 779 {
 780         /* Stop all the virtqueues. */
 781         vdev->config->reset(vdev);
 782         vdev->config->del_vqs(vdev);
 783 }
 784
 785 static int virtscsi_init(struct virtio_device *vdev,
 786                          struct virtio_scsi *vscsi)
 787 {
 788         int err;
 789         u32 i;
 790         u32 num_vqs;
 791         vq_callback_t **callbacks;
 792         const char **names;
 793         struct virtqueue **vqs;
 794         struct irq_affinity desc = { .pre_vectors = 2 };
 795
 796         num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;
 797         vqs = kmalloc_array(num_vqs, sizeof(struct virtqueue *), GFP_KERNEL);
 798         callbacks = kmalloc_array(num_vqs, sizeof(vq_callback_t *),
 799                                   GFP_KERNEL);
 800         names = kmalloc_array(num_vqs, sizeof(char *), GFP_KERNEL);
 801
 802         if (!callbacks || !vqs || !names) {
 803                 err = -ENOMEM;
 804                 goto out;
 805         }
 806
 807         callbacks[0] = virtscsi_ctrl_done;
 808         callbacks[1] = virtscsi_event_done;
 809         names[0] = "control";
 810         names[1] = "event";
 811         for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) {
 812                 callbacks[i] = virtscsi_req_done;
 813                 names[i] = "request";
 814         }
 815
 816         /* Discover virtqueues and write information to configuration.  */
 817         err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc);
 818         if (err)
 819                 goto out;
 820
 821         virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
 822         virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
 823         for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
 824                 virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
 825                                  vqs[i]);
 826
 827         virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
 828         virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
 829
 830         err = 0;
 831
 832 out:
 833         kfree(names);
 834         kfree(callbacks);
 835         kfree(vqs);
 836         if (err)
 837                 virtscsi_remove_vqs(vdev);
 838         return err;
 839 }
 840
 841 static int virtscsi_probe(struct virtio_device *vdev)
 842 {
 843         struct Scsi_Host *shost;
 844         struct virtio_scsi *vscsi;
 845         int err;
 846         u32 sg_elems, num_targets;
 847         u32 cmd_per_lun;
 848         u32 num_queues;
 849
 850         if (!vdev->config->get) {
 851                 dev_err(&vdev->dev, "%s failure: config access disabled\n",
 852                         __func__);
 853                 return -EINVAL;
 854         }
 855
 856         /* We need to know how many queues before we allocate. */
 857         num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
 858         num_queues = min_t(unsigned int, nr_cpu_ids, num_queues);
 859
 860         num_targets = virtscsi_config_get(vdev, max_target) + 1;
 861
 862         shost = scsi_host_alloc(&virtscsi_host_template,
 863                                 struct_size(vscsi, req_vqs, num_queues));
 864         if (!shost)
 865                 return -ENOMEM;
 866
 867         sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
 868         shost->sg_tablesize = sg_elems;
 869         vscsi = shost_priv(shost);
 870         vscsi->vdev = vdev;
 871         vscsi->num_queues = num_queues;
 872         vdev->priv = shost;
 873
 874         err = virtscsi_init(vdev, vscsi);
 875         if (err)
 876                 goto virtscsi_init_failed;
 877
 878         shost->can_queue = virtqueue_get_vring_size(vscsi->req_vqs[0].vq);
 879
 880         cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
 881         shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
 882         shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
 883
 884         /* LUNs > 256 are reported with format 1, so they go in the range
 885          * 16640-32767.
 886          */
 887         shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
 888         shost->max_id = num_targets;
 889         shost->max_channel = 0;
 890         shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
 891         shost->nr_hw_queues = num_queues;
 892
 893 #ifdef CONFIG_BLK_DEV_INTEGRITY
 894         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
 895                 int host_prot;
 896
 897                 host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
 898                             SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
 899                             SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
 900
 901                 scsi_host_set_prot(shost, host_prot);
 902                 scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC);
 903         }
 904 #endif
 905
 906         err = scsi_add_host(shost, &vdev->dev);
 907         if (err)
 908                 goto scsi_add_host_failed;
 909
 910         virtio_device_ready(vdev);
 911
 912         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 913                 virtscsi_kick_event_all(vscsi);
 914
 915         scsi_scan_host(shost);
 916         return 0;
 917
 918 scsi_add_host_failed:
 919         vdev->config->del_vqs(vdev);
 920 virtscsi_init_failed:
 921         scsi_host_put(shost);
 922         return err;
 923 }
 924
 925 static void virtscsi_remove(struct virtio_device *vdev)
 926 {
 927         struct Scsi_Host *shost = virtio_scsi_host(vdev);
 928         struct virtio_scsi *vscsi = shost_priv(shost);
 929
 930         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 931                 virtscsi_cancel_event_work(vscsi);
 932
 933         scsi_remove_host(shost);
 934         virtscsi_remove_vqs(vdev);
 935         scsi_host_put(shost);
 936 }
 937
 938 #ifdef CONFIG_PM_SLEEP
 939 static int virtscsi_freeze(struct virtio_device *vdev)
 940 {
 941         virtscsi_remove_vqs(vdev);
 942         return 0;
 943 }
 944
 945 static int virtscsi_restore(struct virtio_device *vdev)
 946 {
 947         struct Scsi_Host *sh = virtio_scsi_host(vdev);
 948         struct virtio_scsi *vscsi = shost_priv(sh);
 949         int err;
 950
 951         err = virtscsi_init(vdev, vscsi);
 952         if (err)
 953                 return err;
 954
 955         virtio_device_ready(vdev);
 956
 957         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 958                 virtscsi_kick_event_all(vscsi);
 959
 960         return err;
 961 }
 962 #endif
 963
 964 static struct virtio_device_id id_table[] = {
 965         { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
 966         { 0 },
 967 };
 968
 969 static unsigned int features[] = {
 970         VIRTIO_SCSI_F_HOTPLUG,
 971         VIRTIO_SCSI_F_CHANGE,
 972 #ifdef CONFIG_BLK_DEV_INTEGRITY
 973         VIRTIO_SCSI_F_T10_PI,
 974 #endif
 975 };
 976
 977 static struct virtio_driver virtio_scsi_driver = {
 978         .feature_table = features,
 979         .feature_table_size = ARRAY_SIZE(features),
 980         .driver.name = KBUILD_MODNAME,
 981         .driver.owner = THIS_MODULE,
 982         .id_table = id_table,
 983         .probe = virtscsi_probe,
 984 #ifdef CONFIG_PM_SLEEP
 985         .freeze = virtscsi_freeze,
 986         .restore = virtscsi_restore,
 987 #endif
 988         .remove = virtscsi_remove,
 989 };
 990
 991 static int __init init(void)
 992 {
 993         int ret = -ENOMEM;
 994
 995         virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
 996         if (!virtscsi_cmd_cache) {
 997                 pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
 998                 goto error;
 999         }
1000
1001
1002         virtscsi_cmd_pool =
1003                 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
1004                                          virtscsi_cmd_cache);
1005         if (!virtscsi_cmd_pool) {
1006                 pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
1007                 goto error;
1008         }
1009         ret = register_virtio_driver(&virtio_scsi_driver);
1010         if (ret < 0)
1011                 goto error;
1012
1013         return 0;
1014
1015 error:
1016         mempool_destroy(virtscsi_cmd_pool);
1017         virtscsi_cmd_pool = NULL;
1018         kmem_cache_destroy(virtscsi_cmd_cache);
1019         virtscsi_cmd_cache = NULL;
1020         return ret;
1021 }
1022
1023 static void __exit fini(void)
1024 {
1025         unregister_virtio_driver(&virtio_scsi_driver);
1026         mempool_destroy(virtscsi_cmd_pool);
1027         kmem_cache_destroy(virtscsi_cmd_cache);
1028 }
1029 module_init(init);
1030 module_exit(fini);
1031
1032 MODULE_DEVICE_TABLE(virtio, id_table);
1033 MODULE_DESCRIPTION("Virtio SCSI HBA driver");
1034 MODULE_LICENSE("GPL");