drivers/scsi/virtio_scsi.c

   1 /*
   2  * Virtio SCSI HBA driver
   3  *
   4  * Copyright IBM Corp. 2010
   5  * Copyright Red Hat, Inc. 2011
   6  *
   7  * Authors:
   8  *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.com>
   9  *  Paolo Bonzini   <pbonzini@redhat.com>
  10  *
  11  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  12  * See the COPYING file in the top-level directory.
  13  *
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <linux/mempool.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 <scsi/scsi_host.h>
  24 #include <scsi/scsi_device.h>
  25 #include <scsi/scsi_cmnd.h>
  26
  27 #define VIRTIO_SCSI_MEMPOOL_SZ 64
  28
  29 /* Command queue element */
  30 struct virtio_scsi_cmd {
  31         struct scsi_cmnd *sc;
  32         struct completion *comp;
  33         union {
  34                 struct virtio_scsi_cmd_req       cmd;
  35                 struct virtio_scsi_ctrl_tmf_req  tmf;
  36                 struct virtio_scsi_ctrl_an_req   an;
  37         } req;
  38         union {
  39                 struct virtio_scsi_cmd_resp      cmd;
  40                 struct virtio_scsi_ctrl_tmf_resp tmf;
  41                 struct virtio_scsi_ctrl_an_resp  an;
  42                 struct virtio_scsi_event         evt;
  43         } resp;
  44 } ____cacheline_aligned_in_smp;
  45
  46 /* Driver instance state */
  47 struct virtio_scsi {
  48         /* Protects ctrl_vq, req_vq and sg[] */
  49         spinlock_t vq_lock;
  50
  51         struct virtio_device *vdev;
  52         struct virtqueue *ctrl_vq;
  53         struct virtqueue *event_vq;
  54         struct virtqueue *req_vq;
  55
  56         /* For sglist construction when adding commands to the virtqueue.  */
  57         struct scatterlist sg[];
  58 };
  59
  60 static struct kmem_cache *virtscsi_cmd_cache;
  61 static mempool_t *virtscsi_cmd_pool;
  62
  63 static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
  64 {
  65         return vdev->priv;
  66 }
  67
  68 static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
  69 {
  70         if (!resid)
  71                 return;
  72
  73         if (!scsi_bidi_cmnd(sc)) {
  74                 scsi_set_resid(sc, resid);
  75                 return;
  76         }
  77
  78         scsi_in(sc)->resid = min(resid, scsi_in(sc)->length);
  79         scsi_out(sc)->resid = resid - scsi_in(sc)->resid;
  80 }
  81
  82 /**
  83  * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
  84  *
  85  * Called with vq_lock held.
  86  */
  87 static void virtscsi_complete_cmd(void *buf)
  88 {
  89         struct virtio_scsi_cmd *cmd = buf;
  90         struct scsi_cmnd *sc = cmd->sc;
  91         struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
  92
  93         dev_dbg(&sc->device->sdev_gendev,
  94                 "cmd %p response %u status %#02x sense_len %u\n",
  95                 sc, resp->response, resp->status, resp->sense_len);
  96
  97         sc->result = resp->status;
  98         virtscsi_compute_resid(sc, resp->resid);
  99         switch (resp->response) {
 100         case VIRTIO_SCSI_S_OK:
 101                 set_host_byte(sc, DID_OK);
 102                 break;
 103         case VIRTIO_SCSI_S_OVERRUN:
 104                 set_host_byte(sc, DID_ERROR);
 105                 break;
 106         case VIRTIO_SCSI_S_ABORTED:
 107                 set_host_byte(sc, DID_ABORT);
 108                 break;
 109         case VIRTIO_SCSI_S_BAD_TARGET:
 110                 set_host_byte(sc, DID_BAD_TARGET);
 111                 break;
 112         case VIRTIO_SCSI_S_RESET:
 113                 set_host_byte(sc, DID_RESET);
 114                 break;
 115         case VIRTIO_SCSI_S_BUSY:
 116                 set_host_byte(sc, DID_BUS_BUSY);
 117                 break;
 118         case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
 119                 set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
 120                 break;
 121         case VIRTIO_SCSI_S_TARGET_FAILURE:
 122                 set_host_byte(sc, DID_TARGET_FAILURE);
 123                 break;
 124         case VIRTIO_SCSI_S_NEXUS_FAILURE:
 125                 set_host_byte(sc, DID_NEXUS_FAILURE);
 126                 break;
 127         default:
 128                 scmd_printk(KERN_WARNING, sc, "Unknown response %d",
 129                             resp->response);
 130                 /* fall through */
 131         case VIRTIO_SCSI_S_FAILURE:
 132                 set_host_byte(sc, DID_ERROR);
 133                 break;
 134         }
 135
 136         WARN_ON(resp->sense_len > VIRTIO_SCSI_SENSE_SIZE);
 137         if (sc->sense_buffer) {
 138                 memcpy(sc->sense_buffer, resp->sense,
 139                        min_t(u32, resp->sense_len, VIRTIO_SCSI_SENSE_SIZE));
 140                 if (resp->sense_len)
 141                         set_driver_byte(sc, DRIVER_SENSE);
 142         }
 143
 144         mempool_free(cmd, virtscsi_cmd_pool);
 145         sc->scsi_done(sc);
 146 }
 147
 148 static void virtscsi_vq_done(struct virtqueue *vq, void (*fn)(void *buf))
 149 {
 150         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 151         struct virtio_scsi *vscsi = shost_priv(sh);
 152         void *buf;
 153         unsigned long flags;
 154         unsigned int len;
 155
 156         spin_lock_irqsave(&vscsi->vq_lock, flags);
 157
 158         do {
 159                 virtqueue_disable_cb(vq);
 160                 while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
 161                         fn(buf);
 162         } while (!virtqueue_enable_cb(vq));
 163
 164         spin_unlock_irqrestore(&vscsi->vq_lock, flags);
 165 }
 166
 167 static void virtscsi_req_done(struct virtqueue *vq)
 168 {
 169         virtscsi_vq_done(vq, virtscsi_complete_cmd);
 170 };
 171
 172 static void virtscsi_complete_free(void *buf)
 173 {
 174         struct virtio_scsi_cmd *cmd = buf;
 175
 176         if (cmd->comp)
 177                 complete_all(cmd->comp);
 178         mempool_free(cmd, virtscsi_cmd_pool);
 179 }
 180
 181 static void virtscsi_ctrl_done(struct virtqueue *vq)
 182 {
 183         virtscsi_vq_done(vq, virtscsi_complete_free);
 184 };
 185
 186 static void virtscsi_event_done(struct virtqueue *vq)
 187 {
 188         virtscsi_vq_done(vq, virtscsi_complete_free);
 189 };
 190
 191 static void virtscsi_map_sgl(struct scatterlist *sg, unsigned int *p_idx,
 192                              struct scsi_data_buffer *sdb)
 193 {
 194         struct sg_table *table = &sdb->table;
 195         struct scatterlist *sg_elem;
 196         unsigned int idx = *p_idx;
 197         int i;
 198
 199         for_each_sg(table->sgl, sg_elem, table->nents, i)
 200                 sg_set_buf(&sg[idx++], sg_virt(sg_elem), sg_elem->length);
 201
 202         *p_idx = idx;
 203 }
 204
 205 /**
 206  * virtscsi_map_cmd - map a scsi_cmd to a virtqueue scatterlist
 207  * @vscsi       : virtio_scsi state
 208  * @cmd         : command structure
 209  * @out_num     : number of read-only elements
 210  * @in_num      : number of write-only elements
 211  * @req_size    : size of the request buffer
 212  * @resp_size   : size of the response buffer
 213  *
 214  * Called with vq_lock held.
 215  */
 216 static void virtscsi_map_cmd(struct virtio_scsi *vscsi,
 217                              struct virtio_scsi_cmd *cmd,
 218                              unsigned *out_num, unsigned *in_num,
 219                              size_t req_size, size_t resp_size)
 220 {
 221         struct scsi_cmnd *sc = cmd->sc;
 222         struct scatterlist *sg = vscsi->sg;
 223         unsigned int idx = 0;
 224
 225         if (sc) {
 226                 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 227                 BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
 228
 229                 /* TODO: check feature bit and fail if unsupported?  */
 230                 BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
 231         }
 232
 233         /* Request header.  */
 234         sg_set_buf(&sg[idx++], &cmd->req, req_size);
 235
 236         /* Data-out buffer.  */
 237         if (sc && sc->sc_data_direction != DMA_FROM_DEVICE)
 238                 virtscsi_map_sgl(sg, &idx, scsi_out(sc));
 239
 240         *out_num = idx;
 241
 242         /* Response header.  */
 243         sg_set_buf(&sg[idx++], &cmd->resp, resp_size);
 244
 245         /* Data-in buffer */
 246         if (sc && sc->sc_data_direction != DMA_TO_DEVICE)
 247                 virtscsi_map_sgl(sg, &idx, scsi_in(sc));
 248
 249         *in_num = idx - *out_num;
 250 }
 251
 252 static int virtscsi_kick_cmd(struct virtio_scsi *vscsi, struct virtqueue *vq,
 253                              struct virtio_scsi_cmd *cmd,
 254                              size_t req_size, size_t resp_size, gfp_t gfp)
 255 {
 256         unsigned int out_num, in_num;
 257         unsigned long flags;
 258         int ret;
 259
 260         spin_lock_irqsave(&vscsi->vq_lock, flags);
 261
 262         virtscsi_map_cmd(vscsi, cmd, &out_num, &in_num, req_size, resp_size);
 263
 264         ret = virtqueue_add_buf(vq, vscsi->sg, out_num, in_num, cmd, gfp);
 265         if (ret >= 0)
 266                 virtqueue_kick(vq);
 267
 268         spin_unlock_irqrestore(&vscsi->vq_lock, flags);
 269         return ret;
 270 }
 271
 272 static int virtscsi_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *sc)
 273 {
 274         struct virtio_scsi *vscsi = shost_priv(sh);
 275         struct virtio_scsi_cmd *cmd;
 276         int ret;
 277
 278         dev_dbg(&sc->device->sdev_gendev,
 279                 "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
 280
 281         ret = SCSI_MLQUEUE_HOST_BUSY;
 282         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_ATOMIC);
 283         if (!cmd)
 284                 goto out;
 285
 286         memset(cmd, 0, sizeof(*cmd));
 287         cmd->sc = sc;
 288         cmd->req.cmd = (struct virtio_scsi_cmd_req){
 289                 .lun[0] = 1,
 290                 .lun[1] = sc->device->id,
 291                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 292                 .lun[3] = sc->device->lun & 0xff,
 293                 .tag = (unsigned long)sc,
 294                 .task_attr = VIRTIO_SCSI_S_SIMPLE,
 295                 .prio = 0,
 296                 .crn = 0,
 297         };
 298
 299         BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
 300         memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
 301
 302         if (virtscsi_kick_cmd(vscsi, vscsi->req_vq, cmd,
 303                               sizeof cmd->req.cmd, sizeof cmd->resp.cmd,
 304                               GFP_ATOMIC) >= 0)
 305                 ret = 0;
 306
 307 out:
 308         return ret;
 309 }
 310
 311 static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
 312 {
 313         DECLARE_COMPLETION_ONSTACK(comp);
 314         int ret;
 315
 316         cmd->comp = &comp;
 317         ret = virtscsi_kick_cmd(vscsi, vscsi->ctrl_vq, cmd,
 318                                sizeof cmd->req.tmf, sizeof cmd->resp.tmf,
 319                                GFP_NOIO);
 320         if (ret < 0)
 321                 return FAILED;
 322
 323         wait_for_completion(&comp);
 324         if (cmd->resp.tmf.response != VIRTIO_SCSI_S_OK &&
 325             cmd->resp.tmf.response != VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
 326                 return FAILED;
 327
 328         return SUCCESS;
 329 }
 330
 331 static int virtscsi_device_reset(struct scsi_cmnd *sc)
 332 {
 333         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 334         struct virtio_scsi_cmd *cmd;
 335
 336         sdev_printk(KERN_INFO, sc->device, "device reset\n");
 337         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 338         if (!cmd)
 339                 return FAILED;
 340
 341         memset(cmd, 0, sizeof(*cmd));
 342         cmd->sc = sc;
 343         cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 344                 .type = VIRTIO_SCSI_T_TMF,
 345                 .subtype = VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET,
 346                 .lun[0] = 1,
 347                 .lun[1] = sc->device->id,
 348                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 349                 .lun[3] = sc->device->lun & 0xff,
 350         };
 351         return virtscsi_tmf(vscsi, cmd);
 352 }
 353
 354 static int virtscsi_abort(struct scsi_cmnd *sc)
 355 {
 356         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 357         struct virtio_scsi_cmd *cmd;
 358
 359         scmd_printk(KERN_INFO, sc, "abort\n");
 360         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 361         if (!cmd)
 362                 return FAILED;
 363
 364         memset(cmd, 0, sizeof(*cmd));
 365         cmd->sc = sc;
 366         cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 367                 .type = VIRTIO_SCSI_T_TMF,
 368                 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
 369                 .lun[0] = 1,
 370                 .lun[1] = sc->device->id,
 371                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 372                 .lun[3] = sc->device->lun & 0xff,
 373                 .tag = (unsigned long)sc,
 374         };
 375         return virtscsi_tmf(vscsi, cmd);
 376 }
 377
 378 static struct scsi_host_template virtscsi_host_template = {
 379         .module = THIS_MODULE,
 380         .name = "Virtio SCSI HBA",
 381         .proc_name = "virtio_scsi",
 382         .queuecommand = virtscsi_queuecommand,
 383         .this_id = -1,
 384         .eh_abort_handler = virtscsi_abort,
 385         .eh_device_reset_handler = virtscsi_device_reset,
 386
 387         .can_queue = 1024,
 388         .dma_boundary = UINT_MAX,
 389         .use_clustering = ENABLE_CLUSTERING,
 390 };
 391
 392 #define virtscsi_config_get(vdev, fld) \
 393         ({ \
 394                 typeof(((struct virtio_scsi_config *)0)->fld) __val; \
 395                 vdev->config->get(vdev, \
 396                                   offsetof(struct virtio_scsi_config, fld), \
 397                                   &__val, sizeof(__val)); \
 398                 __val; \
 399         })
 400
 401 #define virtscsi_config_set(vdev, fld, val) \
 402         (void)({ \
 403                 typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
 404                 vdev->config->set(vdev, \
 405                                   offsetof(struct virtio_scsi_config, fld), \
 406                                   &__val, sizeof(__val)); \
 407         })
 408
 409 static int virtscsi_init(struct virtio_device *vdev,
 410                          struct virtio_scsi *vscsi)
 411 {
 412         int err;
 413         struct virtqueue *vqs[3];
 414         vq_callback_t *callbacks[] = {
 415                 virtscsi_ctrl_done,
 416                 virtscsi_event_done,
 417                 virtscsi_req_done
 418         };
 419         const char *names[] = {
 420                 "control",
 421                 "event",
 422                 "request"
 423         };
 424
 425         /* Discover virtqueues and write information to configuration.  */
 426         err = vdev->config->find_vqs(vdev, 3, vqs, callbacks, names);
 427         if (err)
 428                 return err;
 429
 430         vscsi->ctrl_vq = vqs[0];
 431         vscsi->event_vq = vqs[1];
 432         vscsi->req_vq = vqs[2];
 433
 434         virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
 435         virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
 436         return 0;
 437 }
 438
 439 static int __devinit virtscsi_probe(struct virtio_device *vdev)
 440 {
 441         struct Scsi_Host *shost;
 442         struct virtio_scsi *vscsi;
 443         int err;
 444         u32 sg_elems;
 445         u32 cmd_per_lun;
 446
 447         /* We need to know how many segments before we allocate.
 448          * We need an extra sg elements at head and tail.
 449          */
 450         sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
 451
 452         /* Allocate memory and link the structs together.  */
 453         shost = scsi_host_alloc(&virtscsi_host_template,
 454                 sizeof(*vscsi) + sizeof(vscsi->sg[0]) * (sg_elems + 2));
 455
 456         if (!shost)
 457                 return -ENOMEM;
 458
 459         shost->sg_tablesize = sg_elems;
 460         vscsi = shost_priv(shost);
 461         vscsi->vdev = vdev;
 462         vdev->priv = shost;
 463
 464         /* Random initializations.  */
 465         spin_lock_init(&vscsi->vq_lock);
 466         sg_init_table(vscsi->sg, sg_elems + 2);
 467
 468         err = virtscsi_init(vdev, vscsi);
 469         if (err)
 470                 goto virtscsi_init_failed;
 471
 472         cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
 473         shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
 474         shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
 475         shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1;
 476         shost->max_id = virtscsi_config_get(vdev, max_target) + 1;
 477         shost->max_channel = 0;
 478         shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
 479         err = scsi_add_host(shost, &vdev->dev);
 480         if (err)
 481                 goto scsi_add_host_failed;
 482
 483         scsi_scan_host(shost);
 484
 485         return 0;
 486
 487 scsi_add_host_failed:
 488         vdev->config->del_vqs(vdev);
 489 virtscsi_init_failed:
 490         scsi_host_put(shost);
 491         return err;
 492 }
 493
 494 static void virtscsi_remove_vqs(struct virtio_device *vdev)
 495 {
 496         /* Stop all the virtqueues. */
 497         vdev->config->reset(vdev);
 498
 499         vdev->config->del_vqs(vdev);
 500 }
 501
 502 static void __devexit virtscsi_remove(struct virtio_device *vdev)
 503 {
 504         struct Scsi_Host *shost = virtio_scsi_host(vdev);
 505
 506         scsi_remove_host(shost);
 507
 508         virtscsi_remove_vqs(vdev);
 509         scsi_host_put(shost);
 510 }
 511
 512 #ifdef CONFIG_PM
 513 static int virtscsi_freeze(struct virtio_device *vdev)
 514 {
 515         virtscsi_remove_vqs(vdev);
 516         return 0;
 517 }
 518
 519 static int virtscsi_restore(struct virtio_device *vdev)
 520 {
 521         struct Scsi_Host *sh = virtio_scsi_host(vdev);
 522         struct virtio_scsi *vscsi = shost_priv(sh);
 523
 524         return virtscsi_init(vdev, vscsi);
 525 }
 526 #endif
 527
 528 static struct virtio_device_id id_table[] = {
 529         { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
 530         { 0 },
 531 };
 532
 533 static struct virtio_driver virtio_scsi_driver = {
 534         .driver.name = KBUILD_MODNAME,
 535         .driver.owner = THIS_MODULE,
 536         .id_table = id_table,
 537         .probe = virtscsi_probe,
 538 #ifdef CONFIG_PM
 539         .freeze = virtscsi_freeze,
 540         .restore = virtscsi_restore,
 541 #endif
 542         .remove = __devexit_p(virtscsi_remove),
 543 };
 544
 545 static int __init init(void)
 546 {
 547         int ret = -ENOMEM;
 548
 549         virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
 550         if (!virtscsi_cmd_cache) {
 551                 printk(KERN_ERR "kmem_cache_create() for "
 552                                 "virtscsi_cmd_cache failed\n");
 553                 goto error;
 554         }
 555
 556
 557         virtscsi_cmd_pool =
 558                 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
 559                                          virtscsi_cmd_cache);
 560         if (!virtscsi_cmd_pool) {
 561                 printk(KERN_ERR "mempool_create() for"
 562                                 "virtscsi_cmd_pool failed\n");
 563                 goto error;
 564         }
 565         ret = register_virtio_driver(&virtio_scsi_driver);
 566         if (ret < 0)
 567                 goto error;
 568
 569         return 0;
 570
 571 error:
 572         if (virtscsi_cmd_pool) {
 573                 mempool_destroy(virtscsi_cmd_pool);
 574                 virtscsi_cmd_pool = NULL;
 575         }
 576         if (virtscsi_cmd_cache) {
 577                 kmem_cache_destroy(virtscsi_cmd_cache);
 578                 virtscsi_cmd_cache = NULL;
 579         }
 580         return ret;
 581 }
 582
 583 static void __exit fini(void)
 584 {
 585         unregister_virtio_driver(&virtio_scsi_driver);
 586         mempool_destroy(virtscsi_cmd_pool);
 587         kmem_cache_destroy(virtscsi_cmd_cache);
 588 }
 589 module_init(init);
 590 module_exit(fini);
 591
 592 MODULE_DEVICE_TABLE(virtio, id_table);
 593 MODULE_DESCRIPTION("Virtio SCSI HBA driver");
 594 MODULE_LICENSE("GPL");