1 /* 2 * Virtio SCSI HBA driver 3 * 4 * Copyright IBM Corp. 2010 5 * Copyright Red Hat, Inc. 2011 6 * 7 * Authors: 8 * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> 9 * Paolo Bonzini <pbonzini@redhat.com> 10 * 11 * This work is licensed under the terms of the GNU GPL, version 2 or later. 12 * See the COPYING file in the top-level directory. 13 * 14 */ 15 16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 17 18 #include <linux/module.h> 19 #include <linux/slab.h> 20 #include <linux/mempool.h> 21 #include <linux/interrupt.h> 22 #include <linux/virtio.h> 23 #include <linux/virtio_ids.h> 24 #include <linux/virtio_config.h> 25 #include <linux/virtio_scsi.h> 26 #include <linux/cpu.h> 27 #include <linux/blkdev.h> 28 #include <scsi/scsi_host.h> 29 #include <scsi/scsi_device.h> 30 #include <scsi/scsi_cmnd.h> 31 #include <scsi/scsi_tcq.h> 32 #include <scsi/scsi_devinfo.h> 33 #include <linux/seqlock.h> 34 #include <linux/blk-mq-virtio.h> 35 36 #define VIRTIO_SCSI_MEMPOOL_SZ 64 37 #define VIRTIO_SCSI_EVENT_LEN 8 38 #define VIRTIO_SCSI_VQ_BASE 2 39 40 /* Command queue element */ 41 struct virtio_scsi_cmd { 42 struct scsi_cmnd *sc; 43 struct completion *comp; 44 union { 45 struct virtio_scsi_cmd_req cmd; 46 struct virtio_scsi_cmd_req_pi cmd_pi; 47 struct virtio_scsi_ctrl_tmf_req tmf; 48 struct virtio_scsi_ctrl_an_req an; 49 } req; 50 union { 51 struct virtio_scsi_cmd_resp cmd; 52 struct virtio_scsi_ctrl_tmf_resp tmf; 53 struct virtio_scsi_ctrl_an_resp an; 54 struct virtio_scsi_event evt; 55 } resp; 56 } ____cacheline_aligned_in_smp; 57 58 struct virtio_scsi_event_node { 59 struct virtio_scsi *vscsi; 60 struct virtio_scsi_event event; 61 struct work_struct work; 62 }; 63 64 struct virtio_scsi_vq { 65 /* Protects vq */ 66 spinlock_t vq_lock; 67 68 struct virtqueue *vq; 69 }; 70 71 /* 72 * Per-target queue state. 73 * 74 * This struct holds the data needed by the queue steering policy. When a 75 * target is sent multiple requests, we need to drive them to the same queue so 76 * that FIFO processing order is kept. However, if a target was idle, we can 77 * choose a queue arbitrarily. In this case the queue is chosen according to 78 * the current VCPU, so the driver expects the number of request queues to be 79 * equal to the number of VCPUs. This makes it easy and fast to select the 80 * queue, and also lets the driver optimize the IRQ affinity for the virtqueues 81 * (each virtqueue's affinity is set to the CPU that "owns" the queue). 82 * 83 * tgt_seq is held to serialize reading and writing req_vq. 84 * 85 * Decrements of reqs are never concurrent with writes of req_vq: before the 86 * decrement reqs will be != 0; after the decrement the virtqueue completion 87 * routine will not use the req_vq so it can be changed by a new request. 88 * Thus they can happen outside the tgt_seq, provided of course we make reqs 89 * an atomic_t. 90 */ 91 struct virtio_scsi_target_state { 92 seqcount_t tgt_seq; 93 94 /* Count of outstanding requests. */ 95 atomic_t reqs; 96 97 /* Currently active virtqueue for requests sent to this target. */ 98 struct virtio_scsi_vq *req_vq; 99 }; 100 101 /* Driver instance state */ 102 struct virtio_scsi { 103 struct virtio_device *vdev; 104 105 /* Get some buffers ready for event vq */ 106 struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN]; 107 108 u32 num_queues; 109 110 /* If the affinity hint is set for virtqueues */ 111 bool affinity_hint_set; 112 113 struct hlist_node node; 114 115 /* Protected by event_vq lock */ 116 bool stop_events; 117 118 struct virtio_scsi_vq ctrl_vq; 119 struct virtio_scsi_vq event_vq; 120 struct virtio_scsi_vq req_vqs[]; 121 }; 122 123 static struct kmem_cache *virtscsi_cmd_cache; 124 static mempool_t *virtscsi_cmd_pool; 125 126 static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev) 127 { 128 return vdev->priv; 129 } 130 131 static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid) 132 { 133 if (!resid) 134 return; 135 136 if (!scsi_bidi_cmnd(sc)) { 137 scsi_set_resid(sc, resid); 138 return; 139 } 140 141 scsi_in(sc)->resid = min(resid, scsi_in(sc)->length); 142 scsi_out(sc)->resid = resid - scsi_in(sc)->resid; 143 } 144 145 /** 146 * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done 147 * 148 * Called with vq_lock held. 149 */ 150 static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf) 151 { 152 struct virtio_scsi_cmd *cmd = buf; 153 struct scsi_cmnd *sc = cmd->sc; 154 struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd; 155 struct virtio_scsi_target_state *tgt = 156 scsi_target(sc->device)->hostdata; 157 158 dev_dbg(&sc->device->sdev_gendev, 159 "cmd %p response %u status %#02x sense_len %u\n", 160 sc, resp->response, resp->status, resp->sense_len); 161 162 sc->result = resp->status; 163 virtscsi_compute_resid(sc, virtio32_to_cpu(vscsi->vdev, resp->resid)); 164 switch (resp->response) { 165 case VIRTIO_SCSI_S_OK: 166 set_host_byte(sc, DID_OK); 167 break; 168 case VIRTIO_SCSI_S_OVERRUN: 169 set_host_byte(sc, DID_ERROR); 170 break; 171 case VIRTIO_SCSI_S_ABORTED: 172 set_host_byte(sc, DID_ABORT); 173 break; 174 case VIRTIO_SCSI_S_BAD_TARGET: 175 set_host_byte(sc, DID_BAD_TARGET); 176 break; 177 case VIRTIO_SCSI_S_RESET: 178 set_host_byte(sc, DID_RESET); 179 break; 180 case VIRTIO_SCSI_S_BUSY: 181 set_host_byte(sc, DID_BUS_BUSY); 182 break; 183 case VIRTIO_SCSI_S_TRANSPORT_FAILURE: 184 set_host_byte(sc, DID_TRANSPORT_DISRUPTED); 185 break; 186 case VIRTIO_SCSI_S_TARGET_FAILURE: 187 set_host_byte(sc, DID_TARGET_FAILURE); 188 break; 189 case VIRTIO_SCSI_S_NEXUS_FAILURE: 190 set_host_byte(sc, DID_NEXUS_FAILURE); 191 break; 192 default: 193 scmd_printk(KERN_WARNING, sc, "Unknown response %d", 194 resp->response); 195 /* fall through */ 196 case VIRTIO_SCSI_S_FAILURE: 197 set_host_byte(sc, DID_ERROR); 198 break; 199 } 200 201 WARN_ON(virtio32_to_cpu(vscsi->vdev, resp->sense_len) > 202 VIRTIO_SCSI_SENSE_SIZE); 203 if (sc->sense_buffer) { 204 memcpy(sc->sense_buffer, resp->sense, 205 min_t(u32, 206 virtio32_to_cpu(vscsi->vdev, resp->sense_len), 207 VIRTIO_SCSI_SENSE_SIZE)); 208 if (resp->sense_len) 209 set_driver_byte(sc, DRIVER_SENSE); 210 } 211 212 sc->scsi_done(sc); 213 214 atomic_dec(&tgt->reqs); 215 } 216 217 static void virtscsi_vq_done(struct virtio_scsi *vscsi, 218 struct virtio_scsi_vq *virtscsi_vq, 219 void (*fn)(struct virtio_scsi *vscsi, void *buf)) 220 { 221 void *buf; 222 unsigned int len; 223 unsigned long flags; 224 struct virtqueue *vq = virtscsi_vq->vq; 225 226 spin_lock_irqsave(&virtscsi_vq->vq_lock, flags); 227 do { 228 virtqueue_disable_cb(vq); 229 while ((buf = virtqueue_get_buf(vq, &len)) != NULL) 230 fn(vscsi, buf); 231 232 if (unlikely(virtqueue_is_broken(vq))) 233 break; 234 } while (!virtqueue_enable_cb(vq)); 235 spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags); 236 } 237 238 static void virtscsi_req_done(struct virtqueue *vq) 239 { 240 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev); 241 struct virtio_scsi *vscsi = shost_priv(sh); 242 int index = vq->index - VIRTIO_SCSI_VQ_BASE; 243 struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index]; 244 245 virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd); 246 }; 247 248 static void virtscsi_poll_requests(struct virtio_scsi *vscsi) 249 { 250 int i, num_vqs; 251 252 num_vqs = vscsi->num_queues; 253 for (i = 0; i < num_vqs; i++) 254 virtscsi_vq_done(vscsi, &vscsi->req_vqs[i], 255 virtscsi_complete_cmd); 256 } 257 258 static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf) 259 { 260 struct virtio_scsi_cmd *cmd = buf; 261 262 if (cmd->comp) 263 complete(cmd->comp); 264 } 265 266 static void virtscsi_ctrl_done(struct virtqueue *vq) 267 { 268 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev); 269 struct virtio_scsi *vscsi = shost_priv(sh); 270 271 virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free); 272 }; 273 274 static void virtscsi_handle_event(struct work_struct *work); 275 276 static int virtscsi_kick_event(struct virtio_scsi *vscsi, 277 struct virtio_scsi_event_node *event_node) 278 { 279 int err; 280 struct scatterlist sg; 281 unsigned long flags; 282 283 INIT_WORK(&event_node->work, virtscsi_handle_event); 284 sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event)); 285 286 spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags); 287 288 err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node, 289 GFP_ATOMIC); 290 if (!err) 291 virtqueue_kick(vscsi->event_vq.vq); 292 293 spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags); 294 295 return err; 296 } 297 298 static int virtscsi_kick_event_all(struct virtio_scsi *vscsi) 299 { 300 int i; 301 302 for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) { 303 vscsi->event_list[i].vscsi = vscsi; 304 virtscsi_kick_event(vscsi, &vscsi->event_list[i]); 305 } 306 307 return 0; 308 } 309 310 static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi) 311 { 312 int i; 313 314 /* Stop scheduling work before calling cancel_work_sync. */ 315 spin_lock_irq(&vscsi->event_vq.vq_lock); 316 vscsi->stop_events = true; 317 spin_unlock_irq(&vscsi->event_vq.vq_lock); 318 319 for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) 320 cancel_work_sync(&vscsi->event_list[i].work); 321 } 322 323 static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi, 324 struct virtio_scsi_event *event) 325 { 326 struct scsi_device *sdev; 327 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev); 328 unsigned int target = event->lun[1]; 329 unsigned int lun = (event->lun[2] << 8) | event->lun[3]; 330 331 switch (virtio32_to_cpu(vscsi->vdev, event->reason)) { 332 case VIRTIO_SCSI_EVT_RESET_RESCAN: 333 scsi_add_device(shost, 0, target, lun); 334 break; 335 case VIRTIO_SCSI_EVT_RESET_REMOVED: 336 sdev = scsi_device_lookup(shost, 0, target, lun); 337 if (sdev) { 338 scsi_remove_device(sdev); 339 scsi_device_put(sdev); 340 } else { 341 pr_err("SCSI device %d 0 %d %d not found\n", 342 shost->host_no, target, lun); 343 } 344 break; 345 default: 346 pr_info("Unsupport virtio scsi event reason %x\n", event->reason); 347 } 348 } 349 350 static void virtscsi_handle_param_change(struct virtio_scsi *vscsi, 351 struct virtio_scsi_event *event) 352 { 353 struct scsi_device *sdev; 354 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev); 355 unsigned int target = event->lun[1]; 356 unsigned int lun = (event->lun[2] << 8) | event->lun[3]; 357 u8 asc = virtio32_to_cpu(vscsi->vdev, event->reason) & 255; 358 u8 ascq = virtio32_to_cpu(vscsi->vdev, event->reason) >> 8; 359 360 sdev = scsi_device_lookup(shost, 0, target, lun); 361 if (!sdev) { 362 pr_err("SCSI device %d 0 %d %d not found\n", 363 shost->host_no, target, lun); 364 return; 365 } 366 367 /* Handle "Parameters changed", "Mode parameters changed", and 368 "Capacity data has changed". */ 369 if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09)) 370 scsi_rescan_device(&sdev->sdev_gendev); 371 372 scsi_device_put(sdev); 373 } 374 375 static void virtscsi_handle_event(struct work_struct *work) 376 { 377 struct virtio_scsi_event_node *event_node = 378 container_of(work, struct virtio_scsi_event_node, work); 379 struct virtio_scsi *vscsi = event_node->vscsi; 380 struct virtio_scsi_event *event = &event_node->event; 381 382 if (event->event & 383 cpu_to_virtio32(vscsi->vdev, VIRTIO_SCSI_T_EVENTS_MISSED)) { 384 event->event &= ~cpu_to_virtio32(vscsi->vdev, 385 VIRTIO_SCSI_T_EVENTS_MISSED); 386 scsi_scan_host(virtio_scsi_host(vscsi->vdev)); 387 } 388 389 switch (virtio32_to_cpu(vscsi->vdev, event->event)) { 390 case VIRTIO_SCSI_T_NO_EVENT: 391 break; 392 case VIRTIO_SCSI_T_TRANSPORT_RESET: 393 virtscsi_handle_transport_reset(vscsi, event); 394 break; 395 case VIRTIO_SCSI_T_PARAM_CHANGE: 396 virtscsi_handle_param_change(vscsi, event); 397 break; 398 default: 399 pr_err("Unsupport virtio scsi event %x\n", event->event); 400 } 401 virtscsi_kick_event(vscsi, event_node); 402 } 403 404 static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf) 405 { 406 struct virtio_scsi_event_node *event_node = buf; 407 408 if (!vscsi->stop_events) 409 queue_work(system_freezable_wq, &event_node->work); 410 } 411 412 static void virtscsi_event_done(struct virtqueue *vq) 413 { 414 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev); 415 struct virtio_scsi *vscsi = shost_priv(sh); 416 417 virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event); 418 }; 419 420 /** 421 * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue 422 * @vq : the struct virtqueue we're talking about 423 * @cmd : command structure 424 * @req_size : size of the request buffer 425 * @resp_size : size of the response buffer 426 */ 427 static int virtscsi_add_cmd(struct virtqueue *vq, 428 struct virtio_scsi_cmd *cmd, 429 size_t req_size, size_t resp_size) 430 { 431 struct scsi_cmnd *sc = cmd->sc; 432 struct scatterlist *sgs[6], req, resp; 433 struct sg_table *out, *in; 434 unsigned out_num = 0, in_num = 0; 435 436 out = in = NULL; 437 438 if (sc && sc->sc_data_direction != DMA_NONE) { 439 if (sc->sc_data_direction != DMA_FROM_DEVICE) 440 out = &scsi_out(sc)->table; 441 if (sc->sc_data_direction != DMA_TO_DEVICE) 442 in = &scsi_in(sc)->table; 443 } 444 445 /* Request header. */ 446 sg_init_one(&req, &cmd->req, req_size); 447 sgs[out_num++] = &req; 448 449 /* Data-out buffer. */ 450 if (out) { 451 /* Place WRITE protection SGLs before Data OUT payload */ 452 if (scsi_prot_sg_count(sc)) 453 sgs[out_num++] = scsi_prot_sglist(sc); 454 sgs[out_num++] = out->sgl; 455 } 456 457 /* Response header. */ 458 sg_init_one(&resp, &cmd->resp, resp_size); 459 sgs[out_num + in_num++] = &resp; 460 461 /* Data-in buffer */ 462 if (in) { 463 /* Place READ protection SGLs before Data IN payload */ 464 if (scsi_prot_sg_count(sc)) 465 sgs[out_num + in_num++] = scsi_prot_sglist(sc); 466 sgs[out_num + in_num++] = in->sgl; 467 } 468 469 return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC); 470 } 471 472 static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq, 473 struct virtio_scsi_cmd *cmd, 474 size_t req_size, size_t resp_size) 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) 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 blk_rq_sectors(rq) * 524 bi->tuple_size); 525 else if (sc->sc_data_direction == DMA_FROM_DEVICE) 526 cmd_pi->pi_bytesin = cpu_to_virtio32(vdev, 527 blk_rq_sectors(rq) * 528 bi->tuple_size); 529 } 530 #endif 531 532 static int virtscsi_queuecommand(struct virtio_scsi *vscsi, 533 struct virtio_scsi_vq *req_vq, 534 struct scsi_cmnd *sc) 535 { 536 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev); 537 struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc); 538 unsigned long flags; 539 int req_size; 540 int ret; 541 542 BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize); 543 544 /* TODO: check feature bit and fail if unsupported? */ 545 BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL); 546 547 dev_dbg(&sc->device->sdev_gendev, 548 "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]); 549 550 memset(cmd, 0, sizeof(*cmd)); 551 cmd->sc = sc; 552 553 BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE); 554 555 #ifdef CONFIG_BLK_DEV_INTEGRITY 556 if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) { 557 virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, sc); 558 memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len); 559 req_size = sizeof(cmd->req.cmd_pi); 560 } else 561 #endif 562 { 563 virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, sc); 564 memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len); 565 req_size = sizeof(cmd->req.cmd); 566 } 567 568 ret = virtscsi_kick_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd)); 569 if (ret == -EIO) { 570 cmd->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET; 571 spin_lock_irqsave(&req_vq->vq_lock, flags); 572 virtscsi_complete_cmd(vscsi, cmd); 573 spin_unlock_irqrestore(&req_vq->vq_lock, flags); 574 } else if (ret != 0) { 575 return SCSI_MLQUEUE_HOST_BUSY; 576 } 577 return 0; 578 } 579 580 static int virtscsi_queuecommand_single(struct Scsi_Host *sh, 581 struct scsi_cmnd *sc) 582 { 583 struct virtio_scsi *vscsi = shost_priv(sh); 584 struct virtio_scsi_target_state *tgt = 585 scsi_target(sc->device)->hostdata; 586 587 atomic_inc(&tgt->reqs); 588 return virtscsi_queuecommand(vscsi, &vscsi->req_vqs[0], sc); 589 } 590 591 static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi, 592 struct scsi_cmnd *sc) 593 { 594 u32 tag = blk_mq_unique_tag(sc->request); 595 u16 hwq = blk_mq_unique_tag_to_hwq(tag); 596 597 return &vscsi->req_vqs[hwq]; 598 } 599 600 static struct virtio_scsi_vq *virtscsi_pick_vq(struct virtio_scsi *vscsi, 601 struct virtio_scsi_target_state *tgt) 602 { 603 struct virtio_scsi_vq *vq; 604 unsigned long flags; 605 u32 queue_num; 606 607 local_irq_save(flags); 608 if (atomic_inc_return(&tgt->reqs) > 1) { 609 unsigned long seq; 610 611 do { 612 seq = read_seqcount_begin(&tgt->tgt_seq); 613 vq = tgt->req_vq; 614 } while (read_seqcount_retry(&tgt->tgt_seq, seq)); 615 } else { 616 /* no writes can be concurrent because of atomic_t */ 617 write_seqcount_begin(&tgt->tgt_seq); 618 619 /* keep previous req_vq if a reader just arrived */ 620 if (unlikely(atomic_read(&tgt->reqs) > 1)) { 621 vq = tgt->req_vq; 622 goto unlock; 623 } 624 625 queue_num = smp_processor_id(); 626 while (unlikely(queue_num >= vscsi->num_queues)) 627 queue_num -= vscsi->num_queues; 628 tgt->req_vq = vq = &vscsi->req_vqs[queue_num]; 629 unlock: 630 write_seqcount_end(&tgt->tgt_seq); 631 } 632 local_irq_restore(flags); 633 634 return vq; 635 } 636 637 static int virtscsi_queuecommand_multi(struct Scsi_Host *sh, 638 struct scsi_cmnd *sc) 639 { 640 struct virtio_scsi *vscsi = shost_priv(sh); 641 struct virtio_scsi_target_state *tgt = 642 scsi_target(sc->device)->hostdata; 643 struct virtio_scsi_vq *req_vq; 644 645 if (shost_use_blk_mq(sh)) 646 req_vq = virtscsi_pick_vq_mq(vscsi, sc); 647 else 648 req_vq = virtscsi_pick_vq(vscsi, tgt); 649 650 return virtscsi_queuecommand(vscsi, req_vq, sc); 651 } 652 653 static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd) 654 { 655 DECLARE_COMPLETION_ONSTACK(comp); 656 int ret = FAILED; 657 658 cmd->comp = ∁ 659 if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd, 660 sizeof cmd->req.tmf, sizeof cmd->resp.tmf) < 0) 661 goto out; 662 663 wait_for_completion(&comp); 664 if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK || 665 cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED) 666 ret = SUCCESS; 667 668 /* 669 * The spec guarantees that all requests related to the TMF have 670 * been completed, but the callback might not have run yet if 671 * we're using independent interrupts (e.g. MSI). Poll the 672 * virtqueues once. 673 * 674 * In the abort case, sc->scsi_done will do nothing, because 675 * the block layer must have detected a timeout and as a result 676 * REQ_ATOM_COMPLETE has been set. 677 */ 678 virtscsi_poll_requests(vscsi); 679 680 out: 681 mempool_free(cmd, virtscsi_cmd_pool); 682 return ret; 683 } 684 685 static int virtscsi_device_reset(struct scsi_cmnd *sc) 686 { 687 struct virtio_scsi *vscsi = shost_priv(sc->device->host); 688 struct virtio_scsi_cmd *cmd; 689 690 sdev_printk(KERN_INFO, sc->device, "device reset\n"); 691 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO); 692 if (!cmd) 693 return FAILED; 694 695 memset(cmd, 0, sizeof(*cmd)); 696 cmd->sc = sc; 697 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){ 698 .type = VIRTIO_SCSI_T_TMF, 699 .subtype = cpu_to_virtio32(vscsi->vdev, 700 VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET), 701 .lun[0] = 1, 702 .lun[1] = sc->device->id, 703 .lun[2] = (sc->device->lun >> 8) | 0x40, 704 .lun[3] = sc->device->lun & 0xff, 705 }; 706 return virtscsi_tmf(vscsi, cmd); 707 } 708 709 static int virtscsi_device_alloc(struct scsi_device *sdevice) 710 { 711 /* 712 * Passed through SCSI targets (e.g. with qemu's 'scsi-block') 713 * may have transfer limits which come from the host SCSI 714 * controller or something on the host side other than the 715 * target itself. 716 * 717 * To make this work properly, the hypervisor can adjust the 718 * target's VPD information to advertise these limits. But 719 * for that to work, the guest has to look at the VPD pages, 720 * which we won't do by default if it is an SPC-2 device, even 721 * if it does actually support it. 722 * 723 * So, set the blist to always try to read the VPD pages. 724 */ 725 sdevice->sdev_bflags = BLIST_TRY_VPD_PAGES; 726 727 return 0; 728 } 729 730 731 /** 732 * virtscsi_change_queue_depth() - Change a virtscsi target's queue depth 733 * @sdev: Virtscsi target whose queue depth to change 734 * @qdepth: New queue depth 735 */ 736 static int virtscsi_change_queue_depth(struct scsi_device *sdev, int qdepth) 737 { 738 struct Scsi_Host *shost = sdev->host; 739 int max_depth = shost->cmd_per_lun; 740 741 return scsi_change_queue_depth(sdev, min(max_depth, qdepth)); 742 } 743 744 static int virtscsi_abort(struct scsi_cmnd *sc) 745 { 746 struct virtio_scsi *vscsi = shost_priv(sc->device->host); 747 struct virtio_scsi_cmd *cmd; 748 749 scmd_printk(KERN_INFO, sc, "abort\n"); 750 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO); 751 if (!cmd) 752 return FAILED; 753 754 memset(cmd, 0, sizeof(*cmd)); 755 cmd->sc = sc; 756 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){ 757 .type = VIRTIO_SCSI_T_TMF, 758 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK, 759 .lun[0] = 1, 760 .lun[1] = sc->device->id, 761 .lun[2] = (sc->device->lun >> 8) | 0x40, 762 .lun[3] = sc->device->lun & 0xff, 763 .tag = cpu_to_virtio64(vscsi->vdev, (unsigned long)sc), 764 }; 765 return virtscsi_tmf(vscsi, cmd); 766 } 767 768 static int virtscsi_target_alloc(struct scsi_target *starget) 769 { 770 struct Scsi_Host *sh = dev_to_shost(starget->dev.parent); 771 struct virtio_scsi *vscsi = shost_priv(sh); 772 773 struct virtio_scsi_target_state *tgt = 774 kmalloc(sizeof(*tgt), GFP_KERNEL); 775 if (!tgt) 776 return -ENOMEM; 777 778 seqcount_init(&tgt->tgt_seq); 779 atomic_set(&tgt->reqs, 0); 780 tgt->req_vq = &vscsi->req_vqs[0]; 781 782 starget->hostdata = tgt; 783 return 0; 784 } 785 786 static void virtscsi_target_destroy(struct scsi_target *starget) 787 { 788 struct virtio_scsi_target_state *tgt = starget->hostdata; 789 kfree(tgt); 790 } 791 792 static int virtscsi_map_queues(struct Scsi_Host *shost) 793 { 794 struct virtio_scsi *vscsi = shost_priv(shost); 795 796 return blk_mq_virtio_map_queues(&shost->tag_set, vscsi->vdev, 2); 797 } 798 799 static struct scsi_host_template virtscsi_host_template_single = { 800 .module = THIS_MODULE, 801 .name = "Virtio SCSI HBA", 802 .proc_name = "virtio_scsi", 803 .this_id = -1, 804 .cmd_size = sizeof(struct virtio_scsi_cmd), 805 .queuecommand = virtscsi_queuecommand_single, 806 .change_queue_depth = virtscsi_change_queue_depth, 807 .eh_abort_handler = virtscsi_abort, 808 .eh_device_reset_handler = virtscsi_device_reset, 809 .slave_alloc = virtscsi_device_alloc, 810 811 .can_queue = 1024, 812 .dma_boundary = UINT_MAX, 813 .use_clustering = ENABLE_CLUSTERING, 814 .target_alloc = virtscsi_target_alloc, 815 .target_destroy = virtscsi_target_destroy, 816 .track_queue_depth = 1, 817 }; 818 819 static struct scsi_host_template virtscsi_host_template_multi = { 820 .module = THIS_MODULE, 821 .name = "Virtio SCSI HBA", 822 .proc_name = "virtio_scsi", 823 .this_id = -1, 824 .cmd_size = sizeof(struct virtio_scsi_cmd), 825 .queuecommand = virtscsi_queuecommand_multi, 826 .change_queue_depth = virtscsi_change_queue_depth, 827 .eh_abort_handler = virtscsi_abort, 828 .eh_device_reset_handler = virtscsi_device_reset, 829 830 .can_queue = 1024, 831 .dma_boundary = UINT_MAX, 832 .use_clustering = ENABLE_CLUSTERING, 833 .target_alloc = virtscsi_target_alloc, 834 .target_destroy = virtscsi_target_destroy, 835 .map_queues = virtscsi_map_queues, 836 .track_queue_depth = 1, 837 }; 838 839 #define virtscsi_config_get(vdev, fld) \ 840 ({ \ 841 typeof(((struct virtio_scsi_config *)0)->fld) __val; \ 842 virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \ 843 __val; \ 844 }) 845 846 #define virtscsi_config_set(vdev, fld, val) \ 847 do { \ 848 typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \ 849 virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \ 850 } while(0) 851 852 static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq, 853 struct virtqueue *vq) 854 { 855 spin_lock_init(&virtscsi_vq->vq_lock); 856 virtscsi_vq->vq = vq; 857 } 858 859 static void virtscsi_remove_vqs(struct virtio_device *vdev) 860 { 861 /* Stop all the virtqueues. */ 862 vdev->config->reset(vdev); 863 vdev->config->del_vqs(vdev); 864 } 865 866 static int virtscsi_init(struct virtio_device *vdev, 867 struct virtio_scsi *vscsi) 868 { 869 int err; 870 u32 i; 871 u32 num_vqs; 872 vq_callback_t **callbacks; 873 const char **names; 874 struct virtqueue **vqs; 875 struct irq_affinity desc = { .pre_vectors = 2 }; 876 877 num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE; 878 vqs = kmalloc(num_vqs * sizeof(struct virtqueue *), GFP_KERNEL); 879 callbacks = kmalloc(num_vqs * sizeof(vq_callback_t *), GFP_KERNEL); 880 names = kmalloc(num_vqs * sizeof(char *), GFP_KERNEL); 881 882 if (!callbacks || !vqs || !names) { 883 err = -ENOMEM; 884 goto out; 885 } 886 887 callbacks[0] = virtscsi_ctrl_done; 888 callbacks[1] = virtscsi_event_done; 889 names[0] = "control"; 890 names[1] = "event"; 891 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) { 892 callbacks[i] = virtscsi_req_done; 893 names[i] = "request"; 894 } 895 896 /* Discover virtqueues and write information to configuration. */ 897 err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc); 898 if (err) 899 goto out; 900 901 virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]); 902 virtscsi_init_vq(&vscsi->event_vq, vqs[1]); 903 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) 904 virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE], 905 vqs[i]); 906 907 virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE); 908 virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE); 909 910 err = 0; 911 912 out: 913 kfree(names); 914 kfree(callbacks); 915 kfree(vqs); 916 if (err) 917 virtscsi_remove_vqs(vdev); 918 return err; 919 } 920 921 static int virtscsi_probe(struct virtio_device *vdev) 922 { 923 struct Scsi_Host *shost; 924 struct virtio_scsi *vscsi; 925 int err; 926 u32 sg_elems, num_targets; 927 u32 cmd_per_lun; 928 u32 num_queues; 929 struct scsi_host_template *hostt; 930 931 if (!vdev->config->get) { 932 dev_err(&vdev->dev, "%s failure: config access disabled\n", 933 __func__); 934 return -EINVAL; 935 } 936 937 /* We need to know how many queues before we allocate. */ 938 num_queues = virtscsi_config_get(vdev, num_queues) ? : 1; 939 940 num_targets = virtscsi_config_get(vdev, max_target) + 1; 941 942 if (num_queues == 1) 943 hostt = &virtscsi_host_template_single; 944 else 945 hostt = &virtscsi_host_template_multi; 946 947 shost = scsi_host_alloc(hostt, 948 sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues); 949 if (!shost) 950 return -ENOMEM; 951 952 sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1; 953 shost->sg_tablesize = sg_elems; 954 vscsi = shost_priv(shost); 955 vscsi->vdev = vdev; 956 vscsi->num_queues = num_queues; 957 vdev->priv = shost; 958 959 err = virtscsi_init(vdev, vscsi); 960 if (err) 961 goto virtscsi_init_failed; 962 963 cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1; 964 shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue); 965 shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF; 966 967 /* LUNs > 256 are reported with format 1, so they go in the range 968 * 16640-32767. 969 */ 970 shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000; 971 shost->max_id = num_targets; 972 shost->max_channel = 0; 973 shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE; 974 shost->nr_hw_queues = num_queues; 975 976 #ifdef CONFIG_BLK_DEV_INTEGRITY 977 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) { 978 int host_prot; 979 980 host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION | 981 SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION | 982 SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION; 983 984 scsi_host_set_prot(shost, host_prot); 985 scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC); 986 } 987 #endif 988 989 err = scsi_add_host(shost, &vdev->dev); 990 if (err) 991 goto scsi_add_host_failed; 992 993 virtio_device_ready(vdev); 994 995 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) 996 virtscsi_kick_event_all(vscsi); 997 998 scsi_scan_host(shost); 999 return 0; 1000 1001 scsi_add_host_failed: 1002 vdev->config->del_vqs(vdev); 1003 virtscsi_init_failed: 1004 scsi_host_put(shost); 1005 return err; 1006 } 1007 1008 static void virtscsi_remove(struct virtio_device *vdev) 1009 { 1010 struct Scsi_Host *shost = virtio_scsi_host(vdev); 1011 struct virtio_scsi *vscsi = shost_priv(shost); 1012 1013 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) 1014 virtscsi_cancel_event_work(vscsi); 1015 1016 scsi_remove_host(shost); 1017 virtscsi_remove_vqs(vdev); 1018 scsi_host_put(shost); 1019 } 1020 1021 #ifdef CONFIG_PM_SLEEP 1022 static int virtscsi_freeze(struct virtio_device *vdev) 1023 { 1024 virtscsi_remove_vqs(vdev); 1025 return 0; 1026 } 1027 1028 static int virtscsi_restore(struct virtio_device *vdev) 1029 { 1030 struct Scsi_Host *sh = virtio_scsi_host(vdev); 1031 struct virtio_scsi *vscsi = shost_priv(sh); 1032 int err; 1033 1034 err = virtscsi_init(vdev, vscsi); 1035 if (err) 1036 return err; 1037 1038 virtio_device_ready(vdev); 1039 1040 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) 1041 virtscsi_kick_event_all(vscsi); 1042 1043 return err; 1044 } 1045 #endif 1046 1047 static struct virtio_device_id id_table[] = { 1048 { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID }, 1049 { 0 }, 1050 }; 1051 1052 static unsigned int features[] = { 1053 VIRTIO_SCSI_F_HOTPLUG, 1054 VIRTIO_SCSI_F_CHANGE, 1055 #ifdef CONFIG_BLK_DEV_INTEGRITY 1056 VIRTIO_SCSI_F_T10_PI, 1057 #endif 1058 }; 1059 1060 static struct virtio_driver virtio_scsi_driver = { 1061 .feature_table = features, 1062 .feature_table_size = ARRAY_SIZE(features), 1063 .driver.name = KBUILD_MODNAME, 1064 .driver.owner = THIS_MODULE, 1065 .id_table = id_table, 1066 .probe = virtscsi_probe, 1067 #ifdef CONFIG_PM_SLEEP 1068 .freeze = virtscsi_freeze, 1069 .restore = virtscsi_restore, 1070 #endif 1071 .remove = virtscsi_remove, 1072 }; 1073 1074 static int __init init(void) 1075 { 1076 int ret = -ENOMEM; 1077 1078 virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0); 1079 if (!virtscsi_cmd_cache) { 1080 pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n"); 1081 goto error; 1082 } 1083 1084 1085 virtscsi_cmd_pool = 1086 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ, 1087 virtscsi_cmd_cache); 1088 if (!virtscsi_cmd_pool) { 1089 pr_err("mempool_create() for virtscsi_cmd_pool failed\n"); 1090 goto error; 1091 } 1092 ret = register_virtio_driver(&virtio_scsi_driver); 1093 if (ret < 0) 1094 goto error; 1095 1096 return 0; 1097 1098 error: 1099 if (virtscsi_cmd_pool) { 1100 mempool_destroy(virtscsi_cmd_pool); 1101 virtscsi_cmd_pool = NULL; 1102 } 1103 if (virtscsi_cmd_cache) { 1104 kmem_cache_destroy(virtscsi_cmd_cache); 1105 virtscsi_cmd_cache = NULL; 1106 } 1107 return ret; 1108 } 1109 1110 static void __exit fini(void) 1111 { 1112 unregister_virtio_driver(&virtio_scsi_driver); 1113 mempool_destroy(virtscsi_cmd_pool); 1114 kmem_cache_destroy(virtscsi_cmd_cache); 1115 } 1116 module_init(init); 1117 module_exit(fini); 1118 1119 MODULE_DEVICE_TABLE(virtio, id_table); 1120 MODULE_DESCRIPTION("Virtio SCSI HBA driver"); 1121 MODULE_LICENSE("GPL"); 1122