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 cmd->sc = sc; 551 552 BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE); 553 554 #ifdef CONFIG_BLK_DEV_INTEGRITY 555 if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) { 556 virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, sc); 557 memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len); 558 req_size = sizeof(cmd->req.cmd_pi); 559 } else 560 #endif 561 { 562 virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, sc); 563 memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len); 564 req_size = sizeof(cmd->req.cmd); 565 } 566 567 ret = virtscsi_kick_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd)); 568 if (ret == -EIO) { 569 cmd->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET; 570 spin_lock_irqsave(&req_vq->vq_lock, flags); 571 virtscsi_complete_cmd(vscsi, cmd); 572 spin_unlock_irqrestore(&req_vq->vq_lock, flags); 573 } else if (ret != 0) { 574 return SCSI_MLQUEUE_HOST_BUSY; 575 } 576 return 0; 577 } 578 579 static int virtscsi_queuecommand_single(struct Scsi_Host *sh, 580 struct scsi_cmnd *sc) 581 { 582 struct virtio_scsi *vscsi = shost_priv(sh); 583 struct virtio_scsi_target_state *tgt = 584 scsi_target(sc->device)->hostdata; 585 586 atomic_inc(&tgt->reqs); 587 return virtscsi_queuecommand(vscsi, &vscsi->req_vqs[0], sc); 588 } 589 590 static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi, 591 struct scsi_cmnd *sc) 592 { 593 u32 tag = blk_mq_unique_tag(sc->request); 594 u16 hwq = blk_mq_unique_tag_to_hwq(tag); 595 596 return &vscsi->req_vqs[hwq]; 597 } 598 599 static struct virtio_scsi_vq *virtscsi_pick_vq(struct virtio_scsi *vscsi, 600 struct virtio_scsi_target_state *tgt) 601 { 602 struct virtio_scsi_vq *vq; 603 unsigned long flags; 604 u32 queue_num; 605 606 local_irq_save(flags); 607 if (atomic_inc_return(&tgt->reqs) > 1) { 608 unsigned long seq; 609 610 do { 611 seq = read_seqcount_begin(&tgt->tgt_seq); 612 vq = tgt->req_vq; 613 } while (read_seqcount_retry(&tgt->tgt_seq, seq)); 614 } else { 615 /* no writes can be concurrent because of atomic_t */ 616 write_seqcount_begin(&tgt->tgt_seq); 617 618 /* keep previous req_vq if a reader just arrived */ 619 if (unlikely(atomic_read(&tgt->reqs) > 1)) { 620 vq = tgt->req_vq; 621 goto unlock; 622 } 623 624 queue_num = smp_processor_id(); 625 while (unlikely(queue_num >= vscsi->num_queues)) 626 queue_num -= vscsi->num_queues; 627 tgt->req_vq = vq = &vscsi->req_vqs[queue_num]; 628 unlock: 629 write_seqcount_end(&tgt->tgt_seq); 630 } 631 local_irq_restore(flags); 632 633 return vq; 634 } 635 636 static int virtscsi_queuecommand_multi(struct Scsi_Host *sh, 637 struct scsi_cmnd *sc) 638 { 639 struct virtio_scsi *vscsi = shost_priv(sh); 640 struct virtio_scsi_target_state *tgt = 641 scsi_target(sc->device)->hostdata; 642 struct virtio_scsi_vq *req_vq; 643 644 if (shost_use_blk_mq(sh)) 645 req_vq = virtscsi_pick_vq_mq(vscsi, sc); 646 else 647 req_vq = virtscsi_pick_vq(vscsi, tgt); 648 649 return virtscsi_queuecommand(vscsi, req_vq, sc); 650 } 651 652 static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd) 653 { 654 DECLARE_COMPLETION_ONSTACK(comp); 655 int ret = FAILED; 656 657 cmd->comp = ∁ 658 if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd, 659 sizeof cmd->req.tmf, sizeof cmd->resp.tmf) < 0) 660 goto out; 661 662 wait_for_completion(&comp); 663 if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK || 664 cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED) 665 ret = SUCCESS; 666 667 /* 668 * The spec guarantees that all requests related to the TMF have 669 * been completed, but the callback might not have run yet if 670 * we're using independent interrupts (e.g. MSI). Poll the 671 * virtqueues once. 672 * 673 * In the abort case, sc->scsi_done will do nothing, because 674 * the block layer must have detected a timeout and as a result 675 * REQ_ATOM_COMPLETE has been set. 676 */ 677 virtscsi_poll_requests(vscsi); 678 679 out: 680 mempool_free(cmd, virtscsi_cmd_pool); 681 return ret; 682 } 683 684 static int virtscsi_device_reset(struct scsi_cmnd *sc) 685 { 686 struct virtio_scsi *vscsi = shost_priv(sc->device->host); 687 struct virtio_scsi_cmd *cmd; 688 689 sdev_printk(KERN_INFO, sc->device, "device reset\n"); 690 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO); 691 if (!cmd) 692 return FAILED; 693 694 memset(cmd, 0, sizeof(*cmd)); 695 cmd->sc = sc; 696 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){ 697 .type = VIRTIO_SCSI_T_TMF, 698 .subtype = cpu_to_virtio32(vscsi->vdev, 699 VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET), 700 .lun[0] = 1, 701 .lun[1] = sc->device->id, 702 .lun[2] = (sc->device->lun >> 8) | 0x40, 703 .lun[3] = sc->device->lun & 0xff, 704 }; 705 return virtscsi_tmf(vscsi, cmd); 706 } 707 708 static int virtscsi_device_alloc(struct scsi_device *sdevice) 709 { 710 /* 711 * Passed through SCSI targets (e.g. with qemu's 'scsi-block') 712 * may have transfer limits which come from the host SCSI 713 * controller or something on the host side other than the 714 * target itself. 715 * 716 * To make this work properly, the hypervisor can adjust the 717 * target's VPD information to advertise these limits. But 718 * for that to work, the guest has to look at the VPD pages, 719 * which we won't do by default if it is an SPC-2 device, even 720 * if it does actually support it. 721 * 722 * So, set the blist to always try to read the VPD pages. 723 */ 724 sdevice->sdev_bflags = BLIST_TRY_VPD_PAGES; 725 726 return 0; 727 } 728 729 730 /** 731 * virtscsi_change_queue_depth() - Change a virtscsi target's queue depth 732 * @sdev: Virtscsi target whose queue depth to change 733 * @qdepth: New queue depth 734 */ 735 static int virtscsi_change_queue_depth(struct scsi_device *sdev, int qdepth) 736 { 737 struct Scsi_Host *shost = sdev->host; 738 int max_depth = shost->cmd_per_lun; 739 740 return scsi_change_queue_depth(sdev, min(max_depth, qdepth)); 741 } 742 743 static int virtscsi_abort(struct scsi_cmnd *sc) 744 { 745 struct virtio_scsi *vscsi = shost_priv(sc->device->host); 746 struct virtio_scsi_cmd *cmd; 747 748 scmd_printk(KERN_INFO, sc, "abort\n"); 749 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO); 750 if (!cmd) 751 return FAILED; 752 753 memset(cmd, 0, sizeof(*cmd)); 754 cmd->sc = sc; 755 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){ 756 .type = VIRTIO_SCSI_T_TMF, 757 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK, 758 .lun[0] = 1, 759 .lun[1] = sc->device->id, 760 .lun[2] = (sc->device->lun >> 8) | 0x40, 761 .lun[3] = sc->device->lun & 0xff, 762 .tag = cpu_to_virtio64(vscsi->vdev, (unsigned long)sc), 763 }; 764 return virtscsi_tmf(vscsi, cmd); 765 } 766 767 static int virtscsi_target_alloc(struct scsi_target *starget) 768 { 769 struct Scsi_Host *sh = dev_to_shost(starget->dev.parent); 770 struct virtio_scsi *vscsi = shost_priv(sh); 771 772 struct virtio_scsi_target_state *tgt = 773 kmalloc(sizeof(*tgt), GFP_KERNEL); 774 if (!tgt) 775 return -ENOMEM; 776 777 seqcount_init(&tgt->tgt_seq); 778 atomic_set(&tgt->reqs, 0); 779 tgt->req_vq = &vscsi->req_vqs[0]; 780 781 starget->hostdata = tgt; 782 return 0; 783 } 784 785 static void virtscsi_target_destroy(struct scsi_target *starget) 786 { 787 struct virtio_scsi_target_state *tgt = starget->hostdata; 788 kfree(tgt); 789 } 790 791 static int virtscsi_map_queues(struct Scsi_Host *shost) 792 { 793 struct virtio_scsi *vscsi = shost_priv(shost); 794 795 return blk_mq_virtio_map_queues(&shost->tag_set, vscsi->vdev, 2); 796 } 797 798 /* 799 * The host guarantees to respond to each command, although I/O 800 * latencies might be higher than on bare metal. Reset the timer 801 * unconditionally to give the host a chance to perform EH. 802 */ 803 static enum blk_eh_timer_return virtscsi_eh_timed_out(struct scsi_cmnd *scmnd) 804 { 805 return BLK_EH_RESET_TIMER; 806 } 807 808 static struct scsi_host_template virtscsi_host_template_single = { 809 .module = THIS_MODULE, 810 .name = "Virtio SCSI HBA", 811 .proc_name = "virtio_scsi", 812 .this_id = -1, 813 .cmd_size = sizeof(struct virtio_scsi_cmd), 814 .queuecommand = virtscsi_queuecommand_single, 815 .change_queue_depth = virtscsi_change_queue_depth, 816 .eh_abort_handler = virtscsi_abort, 817 .eh_device_reset_handler = virtscsi_device_reset, 818 .eh_timed_out = virtscsi_eh_timed_out, 819 .slave_alloc = virtscsi_device_alloc, 820 821 .dma_boundary = UINT_MAX, 822 .use_clustering = ENABLE_CLUSTERING, 823 .target_alloc = virtscsi_target_alloc, 824 .target_destroy = virtscsi_target_destroy, 825 .track_queue_depth = 1, 826 }; 827 828 static struct scsi_host_template virtscsi_host_template_multi = { 829 .module = THIS_MODULE, 830 .name = "Virtio SCSI HBA", 831 .proc_name = "virtio_scsi", 832 .this_id = -1, 833 .cmd_size = sizeof(struct virtio_scsi_cmd), 834 .queuecommand = virtscsi_queuecommand_multi, 835 .change_queue_depth = virtscsi_change_queue_depth, 836 .eh_abort_handler = virtscsi_abort, 837 .eh_device_reset_handler = virtscsi_device_reset, 838 .eh_timed_out = virtscsi_eh_timed_out, 839 .slave_alloc = virtscsi_device_alloc, 840 841 .dma_boundary = UINT_MAX, 842 .use_clustering = ENABLE_CLUSTERING, 843 .target_alloc = virtscsi_target_alloc, 844 .target_destroy = virtscsi_target_destroy, 845 .map_queues = virtscsi_map_queues, 846 .track_queue_depth = 1, 847 }; 848 849 #define virtscsi_config_get(vdev, fld) \ 850 ({ \ 851 typeof(((struct virtio_scsi_config *)0)->fld) __val; \ 852 virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \ 853 __val; \ 854 }) 855 856 #define virtscsi_config_set(vdev, fld, val) \ 857 do { \ 858 typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \ 859 virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \ 860 } while(0) 861 862 static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq, 863 struct virtqueue *vq) 864 { 865 spin_lock_init(&virtscsi_vq->vq_lock); 866 virtscsi_vq->vq = vq; 867 } 868 869 static void virtscsi_remove_vqs(struct virtio_device *vdev) 870 { 871 /* Stop all the virtqueues. */ 872 vdev->config->reset(vdev); 873 vdev->config->del_vqs(vdev); 874 } 875 876 static int virtscsi_init(struct virtio_device *vdev, 877 struct virtio_scsi *vscsi) 878 { 879 int err; 880 u32 i; 881 u32 num_vqs; 882 vq_callback_t **callbacks; 883 const char **names; 884 struct virtqueue **vqs; 885 struct irq_affinity desc = { .pre_vectors = 2 }; 886 887 num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE; 888 vqs = kmalloc(num_vqs * sizeof(struct virtqueue *), GFP_KERNEL); 889 callbacks = kmalloc(num_vqs * sizeof(vq_callback_t *), GFP_KERNEL); 890 names = kmalloc(num_vqs * sizeof(char *), GFP_KERNEL); 891 892 if (!callbacks || !vqs || !names) { 893 err = -ENOMEM; 894 goto out; 895 } 896 897 callbacks[0] = virtscsi_ctrl_done; 898 callbacks[1] = virtscsi_event_done; 899 names[0] = "control"; 900 names[1] = "event"; 901 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) { 902 callbacks[i] = virtscsi_req_done; 903 names[i] = "request"; 904 } 905 906 /* Discover virtqueues and write information to configuration. */ 907 err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc); 908 if (err) 909 goto out; 910 911 virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]); 912 virtscsi_init_vq(&vscsi->event_vq, vqs[1]); 913 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) 914 virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE], 915 vqs[i]); 916 917 virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE); 918 virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE); 919 920 err = 0; 921 922 out: 923 kfree(names); 924 kfree(callbacks); 925 kfree(vqs); 926 if (err) 927 virtscsi_remove_vqs(vdev); 928 return err; 929 } 930 931 static int virtscsi_probe(struct virtio_device *vdev) 932 { 933 struct Scsi_Host *shost; 934 struct virtio_scsi *vscsi; 935 int err; 936 u32 sg_elems, num_targets; 937 u32 cmd_per_lun; 938 u32 num_queues; 939 struct scsi_host_template *hostt; 940 941 if (!vdev->config->get) { 942 dev_err(&vdev->dev, "%s failure: config access disabled\n", 943 __func__); 944 return -EINVAL; 945 } 946 947 /* We need to know how many queues before we allocate. */ 948 num_queues = virtscsi_config_get(vdev, num_queues) ? : 1; 949 950 num_targets = virtscsi_config_get(vdev, max_target) + 1; 951 952 if (num_queues == 1) 953 hostt = &virtscsi_host_template_single; 954 else 955 hostt = &virtscsi_host_template_multi; 956 957 shost = scsi_host_alloc(hostt, 958 sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues); 959 if (!shost) 960 return -ENOMEM; 961 962 sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1; 963 shost->sg_tablesize = sg_elems; 964 vscsi = shost_priv(shost); 965 vscsi->vdev = vdev; 966 vscsi->num_queues = num_queues; 967 vdev->priv = shost; 968 969 err = virtscsi_init(vdev, vscsi); 970 if (err) 971 goto virtscsi_init_failed; 972 973 shost->can_queue = virtqueue_get_vring_size(vscsi->req_vqs[0].vq); 974 975 cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1; 976 shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue); 977 shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF; 978 979 /* LUNs > 256 are reported with format 1, so they go in the range 980 * 16640-32767. 981 */ 982 shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000; 983 shost->max_id = num_targets; 984 shost->max_channel = 0; 985 shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE; 986 shost->nr_hw_queues = num_queues; 987 988 #ifdef CONFIG_BLK_DEV_INTEGRITY 989 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) { 990 int host_prot; 991 992 host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION | 993 SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION | 994 SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION; 995 996 scsi_host_set_prot(shost, host_prot); 997 scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC); 998 } 999 #endif 1000 1001 err = scsi_add_host(shost, &vdev->dev); 1002 if (err) 1003 goto scsi_add_host_failed; 1004 1005 virtio_device_ready(vdev); 1006 1007 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) 1008 virtscsi_kick_event_all(vscsi); 1009 1010 scsi_scan_host(shost); 1011 return 0; 1012 1013 scsi_add_host_failed: 1014 vdev->config->del_vqs(vdev); 1015 virtscsi_init_failed: 1016 scsi_host_put(shost); 1017 return err; 1018 } 1019 1020 static void virtscsi_remove(struct virtio_device *vdev) 1021 { 1022 struct Scsi_Host *shost = virtio_scsi_host(vdev); 1023 struct virtio_scsi *vscsi = shost_priv(shost); 1024 1025 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) 1026 virtscsi_cancel_event_work(vscsi); 1027 1028 scsi_remove_host(shost); 1029 virtscsi_remove_vqs(vdev); 1030 scsi_host_put(shost); 1031 } 1032 1033 #ifdef CONFIG_PM_SLEEP 1034 static int virtscsi_freeze(struct virtio_device *vdev) 1035 { 1036 virtscsi_remove_vqs(vdev); 1037 return 0; 1038 } 1039 1040 static int virtscsi_restore(struct virtio_device *vdev) 1041 { 1042 struct Scsi_Host *sh = virtio_scsi_host(vdev); 1043 struct virtio_scsi *vscsi = shost_priv(sh); 1044 int err; 1045 1046 err = virtscsi_init(vdev, vscsi); 1047 if (err) 1048 return err; 1049 1050 virtio_device_ready(vdev); 1051 1052 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) 1053 virtscsi_kick_event_all(vscsi); 1054 1055 return err; 1056 } 1057 #endif 1058 1059 static struct virtio_device_id id_table[] = { 1060 { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID }, 1061 { 0 }, 1062 }; 1063 1064 static unsigned int features[] = { 1065 VIRTIO_SCSI_F_HOTPLUG, 1066 VIRTIO_SCSI_F_CHANGE, 1067 #ifdef CONFIG_BLK_DEV_INTEGRITY 1068 VIRTIO_SCSI_F_T10_PI, 1069 #endif 1070 }; 1071 1072 static struct virtio_driver virtio_scsi_driver = { 1073 .feature_table = features, 1074 .feature_table_size = ARRAY_SIZE(features), 1075 .driver.name = KBUILD_MODNAME, 1076 .driver.owner = THIS_MODULE, 1077 .id_table = id_table, 1078 .probe = virtscsi_probe, 1079 #ifdef CONFIG_PM_SLEEP 1080 .freeze = virtscsi_freeze, 1081 .restore = virtscsi_restore, 1082 #endif 1083 .remove = virtscsi_remove, 1084 }; 1085 1086 static int __init init(void) 1087 { 1088 int ret = -ENOMEM; 1089 1090 virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0); 1091 if (!virtscsi_cmd_cache) { 1092 pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n"); 1093 goto error; 1094 } 1095 1096 1097 virtscsi_cmd_pool = 1098 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ, 1099 virtscsi_cmd_cache); 1100 if (!virtscsi_cmd_pool) { 1101 pr_err("mempool_create() for virtscsi_cmd_pool failed\n"); 1102 goto error; 1103 } 1104 ret = register_virtio_driver(&virtio_scsi_driver); 1105 if (ret < 0) 1106 goto error; 1107 1108 return 0; 1109 1110 error: 1111 if (virtscsi_cmd_pool) { 1112 mempool_destroy(virtscsi_cmd_pool); 1113 virtscsi_cmd_pool = NULL; 1114 } 1115 if (virtscsi_cmd_cache) { 1116 kmem_cache_destroy(virtscsi_cmd_cache); 1117 virtscsi_cmd_cache = NULL; 1118 } 1119 return ret; 1120 } 1121 1122 static void __exit fini(void) 1123 { 1124 unregister_virtio_driver(&virtio_scsi_driver); 1125 mempool_destroy(virtscsi_cmd_pool); 1126 kmem_cache_destroy(virtscsi_cmd_cache); 1127 } 1128 module_init(init); 1129 module_exit(fini); 1130 1131 MODULE_DEVICE_TABLE(virtio, id_table); 1132 MODULE_DESCRIPTION("Virtio SCSI HBA driver"); 1133 MODULE_LICENSE("GPL"); 1134