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 /* Currently active virtqueue for requests sent to this target. */ 95 struct virtio_scsi_vq *req_vq; 96 }; 97 98 /* Driver instance state */ 99 struct virtio_scsi { 100 struct virtio_device *vdev; 101 102 /* Get some buffers ready for event vq */ 103 struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN]; 104 105 u32 num_queues; 106 107 /* If the affinity hint is set for virtqueues */ 108 bool affinity_hint_set; 109 110 struct hlist_node node; 111 112 /* Protected by event_vq lock */ 113 bool stop_events; 114 115 struct virtio_scsi_vq ctrl_vq; 116 struct virtio_scsi_vq event_vq; 117 struct virtio_scsi_vq req_vqs[]; 118 }; 119 120 static struct kmem_cache *virtscsi_cmd_cache; 121 static mempool_t *virtscsi_cmd_pool; 122 123 static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev) 124 { 125 return vdev->priv; 126 } 127 128 static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid) 129 { 130 if (!resid) 131 return; 132 133 if (!scsi_bidi_cmnd(sc)) { 134 scsi_set_resid(sc, resid); 135 return; 136 } 137 138 scsi_in(sc)->resid = min(resid, scsi_in(sc)->length); 139 scsi_out(sc)->resid = resid - scsi_in(sc)->resid; 140 } 141 142 /** 143 * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done 144 * 145 * Called with vq_lock held. 146 */ 147 static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf) 148 { 149 struct virtio_scsi_cmd *cmd = buf; 150 struct scsi_cmnd *sc = cmd->sc; 151 struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd; 152 153 dev_dbg(&sc->device->sdev_gendev, 154 "cmd %p response %u status %#02x sense_len %u\n", 155 sc, resp->response, resp->status, resp->sense_len); 156 157 sc->result = resp->status; 158 virtscsi_compute_resid(sc, virtio32_to_cpu(vscsi->vdev, resp->resid)); 159 switch (resp->response) { 160 case VIRTIO_SCSI_S_OK: 161 set_host_byte(sc, DID_OK); 162 break; 163 case VIRTIO_SCSI_S_OVERRUN: 164 set_host_byte(sc, DID_ERROR); 165 break; 166 case VIRTIO_SCSI_S_ABORTED: 167 set_host_byte(sc, DID_ABORT); 168 break; 169 case VIRTIO_SCSI_S_BAD_TARGET: 170 set_host_byte(sc, DID_BAD_TARGET); 171 break; 172 case VIRTIO_SCSI_S_RESET: 173 set_host_byte(sc, DID_RESET); 174 break; 175 case VIRTIO_SCSI_S_BUSY: 176 set_host_byte(sc, DID_BUS_BUSY); 177 break; 178 case VIRTIO_SCSI_S_TRANSPORT_FAILURE: 179 set_host_byte(sc, DID_TRANSPORT_DISRUPTED); 180 break; 181 case VIRTIO_SCSI_S_TARGET_FAILURE: 182 set_host_byte(sc, DID_TARGET_FAILURE); 183 break; 184 case VIRTIO_SCSI_S_NEXUS_FAILURE: 185 set_host_byte(sc, DID_NEXUS_FAILURE); 186 break; 187 default: 188 scmd_printk(KERN_WARNING, sc, "Unknown response %d", 189 resp->response); 190 /* fall through */ 191 case VIRTIO_SCSI_S_FAILURE: 192 set_host_byte(sc, DID_ERROR); 193 break; 194 } 195 196 WARN_ON(virtio32_to_cpu(vscsi->vdev, resp->sense_len) > 197 VIRTIO_SCSI_SENSE_SIZE); 198 if (sc->sense_buffer) { 199 memcpy(sc->sense_buffer, resp->sense, 200 min_t(u32, 201 virtio32_to_cpu(vscsi->vdev, resp->sense_len), 202 VIRTIO_SCSI_SENSE_SIZE)); 203 if (resp->sense_len) 204 set_driver_byte(sc, DRIVER_SENSE); 205 } 206 207 sc->scsi_done(sc); 208 } 209 210 static void virtscsi_vq_done(struct virtio_scsi *vscsi, 211 struct virtio_scsi_vq *virtscsi_vq, 212 void (*fn)(struct virtio_scsi *vscsi, void *buf)) 213 { 214 void *buf; 215 unsigned int len; 216 unsigned long flags; 217 struct virtqueue *vq = virtscsi_vq->vq; 218 219 spin_lock_irqsave(&virtscsi_vq->vq_lock, flags); 220 do { 221 virtqueue_disable_cb(vq); 222 while ((buf = virtqueue_get_buf(vq, &len)) != NULL) 223 fn(vscsi, buf); 224 225 if (unlikely(virtqueue_is_broken(vq))) 226 break; 227 } while (!virtqueue_enable_cb(vq)); 228 spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags); 229 } 230 231 static void virtscsi_req_done(struct virtqueue *vq) 232 { 233 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev); 234 struct virtio_scsi *vscsi = shost_priv(sh); 235 int index = vq->index - VIRTIO_SCSI_VQ_BASE; 236 struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index]; 237 238 virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd); 239 }; 240 241 static void virtscsi_poll_requests(struct virtio_scsi *vscsi) 242 { 243 int i, num_vqs; 244 245 num_vqs = vscsi->num_queues; 246 for (i = 0; i < num_vqs; i++) 247 virtscsi_vq_done(vscsi, &vscsi->req_vqs[i], 248 virtscsi_complete_cmd); 249 } 250 251 static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf) 252 { 253 struct virtio_scsi_cmd *cmd = buf; 254 255 if (cmd->comp) 256 complete(cmd->comp); 257 } 258 259 static void virtscsi_ctrl_done(struct virtqueue *vq) 260 { 261 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev); 262 struct virtio_scsi *vscsi = shost_priv(sh); 263 264 virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free); 265 }; 266 267 static void virtscsi_handle_event(struct work_struct *work); 268 269 static int virtscsi_kick_event(struct virtio_scsi *vscsi, 270 struct virtio_scsi_event_node *event_node) 271 { 272 int err; 273 struct scatterlist sg; 274 unsigned long flags; 275 276 INIT_WORK(&event_node->work, virtscsi_handle_event); 277 sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event)); 278 279 spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags); 280 281 err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node, 282 GFP_ATOMIC); 283 if (!err) 284 virtqueue_kick(vscsi->event_vq.vq); 285 286 spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags); 287 288 return err; 289 } 290 291 static int virtscsi_kick_event_all(struct virtio_scsi *vscsi) 292 { 293 int i; 294 295 for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) { 296 vscsi->event_list[i].vscsi = vscsi; 297 virtscsi_kick_event(vscsi, &vscsi->event_list[i]); 298 } 299 300 return 0; 301 } 302 303 static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi) 304 { 305 int i; 306 307 /* Stop scheduling work before calling cancel_work_sync. */ 308 spin_lock_irq(&vscsi->event_vq.vq_lock); 309 vscsi->stop_events = true; 310 spin_unlock_irq(&vscsi->event_vq.vq_lock); 311 312 for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) 313 cancel_work_sync(&vscsi->event_list[i].work); 314 } 315 316 static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi, 317 struct virtio_scsi_event *event) 318 { 319 struct scsi_device *sdev; 320 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev); 321 unsigned int target = event->lun[1]; 322 unsigned int lun = (event->lun[2] << 8) | event->lun[3]; 323 324 switch (virtio32_to_cpu(vscsi->vdev, event->reason)) { 325 case VIRTIO_SCSI_EVT_RESET_RESCAN: 326 scsi_add_device(shost, 0, target, lun); 327 break; 328 case VIRTIO_SCSI_EVT_RESET_REMOVED: 329 sdev = scsi_device_lookup(shost, 0, target, lun); 330 if (sdev) { 331 scsi_remove_device(sdev); 332 scsi_device_put(sdev); 333 } else { 334 pr_err("SCSI device %d 0 %d %d not found\n", 335 shost->host_no, target, lun); 336 } 337 break; 338 default: 339 pr_info("Unsupport virtio scsi event reason %x\n", event->reason); 340 } 341 } 342 343 static void virtscsi_handle_param_change(struct virtio_scsi *vscsi, 344 struct virtio_scsi_event *event) 345 { 346 struct scsi_device *sdev; 347 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev); 348 unsigned int target = event->lun[1]; 349 unsigned int lun = (event->lun[2] << 8) | event->lun[3]; 350 u8 asc = virtio32_to_cpu(vscsi->vdev, event->reason) & 255; 351 u8 ascq = virtio32_to_cpu(vscsi->vdev, event->reason) >> 8; 352 353 sdev = scsi_device_lookup(shost, 0, target, lun); 354 if (!sdev) { 355 pr_err("SCSI device %d 0 %d %d not found\n", 356 shost->host_no, target, lun); 357 return; 358 } 359 360 /* Handle "Parameters changed", "Mode parameters changed", and 361 "Capacity data has changed". */ 362 if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09)) 363 scsi_rescan_device(&sdev->sdev_gendev); 364 365 scsi_device_put(sdev); 366 } 367 368 static void virtscsi_handle_event(struct work_struct *work) 369 { 370 struct virtio_scsi_event_node *event_node = 371 container_of(work, struct virtio_scsi_event_node, work); 372 struct virtio_scsi *vscsi = event_node->vscsi; 373 struct virtio_scsi_event *event = &event_node->event; 374 375 if (event->event & 376 cpu_to_virtio32(vscsi->vdev, VIRTIO_SCSI_T_EVENTS_MISSED)) { 377 event->event &= ~cpu_to_virtio32(vscsi->vdev, 378 VIRTIO_SCSI_T_EVENTS_MISSED); 379 scsi_scan_host(virtio_scsi_host(vscsi->vdev)); 380 } 381 382 switch (virtio32_to_cpu(vscsi->vdev, event->event)) { 383 case VIRTIO_SCSI_T_NO_EVENT: 384 break; 385 case VIRTIO_SCSI_T_TRANSPORT_RESET: 386 virtscsi_handle_transport_reset(vscsi, event); 387 break; 388 case VIRTIO_SCSI_T_PARAM_CHANGE: 389 virtscsi_handle_param_change(vscsi, event); 390 break; 391 default: 392 pr_err("Unsupport virtio scsi event %x\n", event->event); 393 } 394 virtscsi_kick_event(vscsi, event_node); 395 } 396 397 static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf) 398 { 399 struct virtio_scsi_event_node *event_node = buf; 400 401 if (!vscsi->stop_events) 402 queue_work(system_freezable_wq, &event_node->work); 403 } 404 405 static void virtscsi_event_done(struct virtqueue *vq) 406 { 407 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev); 408 struct virtio_scsi *vscsi = shost_priv(sh); 409 410 virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event); 411 }; 412 413 /** 414 * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue 415 * @vq : the struct virtqueue we're talking about 416 * @cmd : command structure 417 * @req_size : size of the request buffer 418 * @resp_size : size of the response buffer 419 */ 420 static int virtscsi_add_cmd(struct virtqueue *vq, 421 struct virtio_scsi_cmd *cmd, 422 size_t req_size, size_t resp_size) 423 { 424 struct scsi_cmnd *sc = cmd->sc; 425 struct scatterlist *sgs[6], req, resp; 426 struct sg_table *out, *in; 427 unsigned out_num = 0, in_num = 0; 428 429 out = in = NULL; 430 431 if (sc && sc->sc_data_direction != DMA_NONE) { 432 if (sc->sc_data_direction != DMA_FROM_DEVICE) 433 out = &scsi_out(sc)->table; 434 if (sc->sc_data_direction != DMA_TO_DEVICE) 435 in = &scsi_in(sc)->table; 436 } 437 438 /* Request header. */ 439 sg_init_one(&req, &cmd->req, req_size); 440 sgs[out_num++] = &req; 441 442 /* Data-out buffer. */ 443 if (out) { 444 /* Place WRITE protection SGLs before Data OUT payload */ 445 if (scsi_prot_sg_count(sc)) 446 sgs[out_num++] = scsi_prot_sglist(sc); 447 sgs[out_num++] = out->sgl; 448 } 449 450 /* Response header. */ 451 sg_init_one(&resp, &cmd->resp, resp_size); 452 sgs[out_num + in_num++] = &resp; 453 454 /* Data-in buffer */ 455 if (in) { 456 /* Place READ protection SGLs before Data IN payload */ 457 if (scsi_prot_sg_count(sc)) 458 sgs[out_num + in_num++] = scsi_prot_sglist(sc); 459 sgs[out_num + in_num++] = in->sgl; 460 } 461 462 return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC); 463 } 464 465 static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq, 466 struct virtio_scsi_cmd *cmd, 467 size_t req_size, size_t resp_size) 468 { 469 unsigned long flags; 470 int err; 471 bool needs_kick = false; 472 473 spin_lock_irqsave(&vq->vq_lock, flags); 474 err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size); 475 if (!err) 476 needs_kick = virtqueue_kick_prepare(vq->vq); 477 478 spin_unlock_irqrestore(&vq->vq_lock, flags); 479 480 if (needs_kick) 481 virtqueue_notify(vq->vq); 482 return err; 483 } 484 485 static void virtio_scsi_init_hdr(struct virtio_device *vdev, 486 struct virtio_scsi_cmd_req *cmd, 487 struct scsi_cmnd *sc) 488 { 489 cmd->lun[0] = 1; 490 cmd->lun[1] = sc->device->id; 491 cmd->lun[2] = (sc->device->lun >> 8) | 0x40; 492 cmd->lun[3] = sc->device->lun & 0xff; 493 cmd->tag = cpu_to_virtio64(vdev, (unsigned long)sc); 494 cmd->task_attr = VIRTIO_SCSI_S_SIMPLE; 495 cmd->prio = 0; 496 cmd->crn = 0; 497 } 498 499 #ifdef CONFIG_BLK_DEV_INTEGRITY 500 static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev, 501 struct virtio_scsi_cmd_req_pi *cmd_pi, 502 struct scsi_cmnd *sc) 503 { 504 struct request *rq = sc->request; 505 struct blk_integrity *bi; 506 507 virtio_scsi_init_hdr(vdev, (struct virtio_scsi_cmd_req *)cmd_pi, sc); 508 509 if (!rq || !scsi_prot_sg_count(sc)) 510 return; 511 512 bi = blk_get_integrity(rq->rq_disk); 513 514 if (sc->sc_data_direction == DMA_TO_DEVICE) 515 cmd_pi->pi_bytesout = cpu_to_virtio32(vdev, 516 blk_rq_sectors(rq) * 517 bi->tuple_size); 518 else if (sc->sc_data_direction == DMA_FROM_DEVICE) 519 cmd_pi->pi_bytesin = cpu_to_virtio32(vdev, 520 blk_rq_sectors(rq) * 521 bi->tuple_size); 522 } 523 #endif 524 525 static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi, 526 struct scsi_cmnd *sc) 527 { 528 u32 tag = blk_mq_unique_tag(sc->request); 529 u16 hwq = blk_mq_unique_tag_to_hwq(tag); 530 531 return &vscsi->req_vqs[hwq]; 532 } 533 534 static int virtscsi_queuecommand(struct Scsi_Host *shost, 535 struct scsi_cmnd *sc) 536 { 537 struct virtio_scsi *vscsi = shost_priv(shost); 538 struct virtio_scsi_vq *req_vq = virtscsi_pick_vq_mq(vscsi, sc); 539 struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc); 540 unsigned long flags; 541 int req_size; 542 int ret; 543 544 BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize); 545 546 /* TODO: check feature bit and fail if unsupported? */ 547 BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL); 548 549 dev_dbg(&sc->device->sdev_gendev, 550 "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]); 551 552 cmd->sc = sc; 553 554 BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE); 555 556 #ifdef CONFIG_BLK_DEV_INTEGRITY 557 if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) { 558 virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, sc); 559 memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len); 560 req_size = sizeof(cmd->req.cmd_pi); 561 } else 562 #endif 563 { 564 virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, sc); 565 memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len); 566 req_size = sizeof(cmd->req.cmd); 567 } 568 569 ret = virtscsi_kick_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd)); 570 if (ret == -EIO) { 571 cmd->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET; 572 spin_lock_irqsave(&req_vq->vq_lock, flags); 573 virtscsi_complete_cmd(vscsi, cmd); 574 spin_unlock_irqrestore(&req_vq->vq_lock, flags); 575 } else if (ret != 0) { 576 return SCSI_MLQUEUE_HOST_BUSY; 577 } 578 return 0; 579 } 580 581 static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd) 582 { 583 DECLARE_COMPLETION_ONSTACK(comp); 584 int ret = FAILED; 585 586 cmd->comp = ∁ 587 if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd, 588 sizeof cmd->req.tmf, sizeof cmd->resp.tmf) < 0) 589 goto out; 590 591 wait_for_completion(&comp); 592 if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK || 593 cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED) 594 ret = SUCCESS; 595 596 /* 597 * The spec guarantees that all requests related to the TMF have 598 * been completed, but the callback might not have run yet if 599 * we're using independent interrupts (e.g. MSI). Poll the 600 * virtqueues once. 601 * 602 * In the abort case, sc->scsi_done will do nothing, because 603 * the block layer must have detected a timeout and as a result 604 * REQ_ATOM_COMPLETE has been set. 605 */ 606 virtscsi_poll_requests(vscsi); 607 608 out: 609 mempool_free(cmd, virtscsi_cmd_pool); 610 return ret; 611 } 612 613 static int virtscsi_device_reset(struct scsi_cmnd *sc) 614 { 615 struct virtio_scsi *vscsi = shost_priv(sc->device->host); 616 struct virtio_scsi_cmd *cmd; 617 618 sdev_printk(KERN_INFO, sc->device, "device reset\n"); 619 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO); 620 if (!cmd) 621 return FAILED; 622 623 memset(cmd, 0, sizeof(*cmd)); 624 cmd->sc = sc; 625 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){ 626 .type = VIRTIO_SCSI_T_TMF, 627 .subtype = cpu_to_virtio32(vscsi->vdev, 628 VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET), 629 .lun[0] = 1, 630 .lun[1] = sc->device->id, 631 .lun[2] = (sc->device->lun >> 8) | 0x40, 632 .lun[3] = sc->device->lun & 0xff, 633 }; 634 return virtscsi_tmf(vscsi, cmd); 635 } 636 637 static int virtscsi_device_alloc(struct scsi_device *sdevice) 638 { 639 /* 640 * Passed through SCSI targets (e.g. with qemu's 'scsi-block') 641 * may have transfer limits which come from the host SCSI 642 * controller or something on the host side other than the 643 * target itself. 644 * 645 * To make this work properly, the hypervisor can adjust the 646 * target's VPD information to advertise these limits. But 647 * for that to work, the guest has to look at the VPD pages, 648 * which we won't do by default if it is an SPC-2 device, even 649 * if it does actually support it. 650 * 651 * So, set the blist to always try to read the VPD pages. 652 */ 653 sdevice->sdev_bflags = BLIST_TRY_VPD_PAGES; 654 655 return 0; 656 } 657 658 659 /** 660 * virtscsi_change_queue_depth() - Change a virtscsi target's queue depth 661 * @sdev: Virtscsi target whose queue depth to change 662 * @qdepth: New queue depth 663 */ 664 static int virtscsi_change_queue_depth(struct scsi_device *sdev, int qdepth) 665 { 666 struct Scsi_Host *shost = sdev->host; 667 int max_depth = shost->cmd_per_lun; 668 669 return scsi_change_queue_depth(sdev, min(max_depth, qdepth)); 670 } 671 672 static int virtscsi_abort(struct scsi_cmnd *sc) 673 { 674 struct virtio_scsi *vscsi = shost_priv(sc->device->host); 675 struct virtio_scsi_cmd *cmd; 676 677 scmd_printk(KERN_INFO, sc, "abort\n"); 678 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO); 679 if (!cmd) 680 return FAILED; 681 682 memset(cmd, 0, sizeof(*cmd)); 683 cmd->sc = sc; 684 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){ 685 .type = VIRTIO_SCSI_T_TMF, 686 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK, 687 .lun[0] = 1, 688 .lun[1] = sc->device->id, 689 .lun[2] = (sc->device->lun >> 8) | 0x40, 690 .lun[3] = sc->device->lun & 0xff, 691 .tag = cpu_to_virtio64(vscsi->vdev, (unsigned long)sc), 692 }; 693 return virtscsi_tmf(vscsi, cmd); 694 } 695 696 static int virtscsi_target_alloc(struct scsi_target *starget) 697 { 698 struct Scsi_Host *sh = dev_to_shost(starget->dev.parent); 699 struct virtio_scsi *vscsi = shost_priv(sh); 700 701 struct virtio_scsi_target_state *tgt = 702 kmalloc(sizeof(*tgt), GFP_KERNEL); 703 if (!tgt) 704 return -ENOMEM; 705 706 seqcount_init(&tgt->tgt_seq); 707 tgt->req_vq = &vscsi->req_vqs[0]; 708 709 starget->hostdata = tgt; 710 return 0; 711 } 712 713 static void virtscsi_target_destroy(struct scsi_target *starget) 714 { 715 struct virtio_scsi_target_state *tgt = starget->hostdata; 716 kfree(tgt); 717 } 718 719 static int virtscsi_map_queues(struct Scsi_Host *shost) 720 { 721 struct virtio_scsi *vscsi = shost_priv(shost); 722 723 return blk_mq_virtio_map_queues(&shost->tag_set, vscsi->vdev, 2); 724 } 725 726 /* 727 * The host guarantees to respond to each command, although I/O 728 * latencies might be higher than on bare metal. Reset the timer 729 * unconditionally to give the host a chance to perform EH. 730 */ 731 static enum blk_eh_timer_return virtscsi_eh_timed_out(struct scsi_cmnd *scmnd) 732 { 733 return BLK_EH_RESET_TIMER; 734 } 735 736 static struct scsi_host_template virtscsi_host_template = { 737 .module = THIS_MODULE, 738 .name = "Virtio SCSI HBA", 739 .proc_name = "virtio_scsi", 740 .this_id = -1, 741 .cmd_size = sizeof(struct virtio_scsi_cmd), 742 .queuecommand = virtscsi_queuecommand, 743 .change_queue_depth = virtscsi_change_queue_depth, 744 .eh_abort_handler = virtscsi_abort, 745 .eh_device_reset_handler = virtscsi_device_reset, 746 .eh_timed_out = virtscsi_eh_timed_out, 747 .slave_alloc = virtscsi_device_alloc, 748 749 .dma_boundary = UINT_MAX, 750 .use_clustering = ENABLE_CLUSTERING, 751 .target_alloc = virtscsi_target_alloc, 752 .target_destroy = virtscsi_target_destroy, 753 .map_queues = virtscsi_map_queues, 754 .track_queue_depth = 1, 755 .force_blk_mq = 1, 756 }; 757 758 #define virtscsi_config_get(vdev, fld) \ 759 ({ \ 760 typeof(((struct virtio_scsi_config *)0)->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 typeof(((struct virtio_scsi_config *)0)->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(num_vqs * sizeof(struct virtqueue *), GFP_KERNEL); 798 callbacks = kmalloc(num_vqs * sizeof(vq_callback_t *), GFP_KERNEL); 799 names = kmalloc(num_vqs * sizeof(char *), GFP_KERNEL); 800 801 if (!callbacks || !vqs || !names) { 802 err = -ENOMEM; 803 goto out; 804 } 805 806 callbacks[0] = virtscsi_ctrl_done; 807 callbacks[1] = virtscsi_event_done; 808 names[0] = "control"; 809 names[1] = "event"; 810 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) { 811 callbacks[i] = virtscsi_req_done; 812 names[i] = "request"; 813 } 814 815 /* Discover virtqueues and write information to configuration. */ 816 err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc); 817 if (err) 818 goto out; 819 820 virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]); 821 virtscsi_init_vq(&vscsi->event_vq, vqs[1]); 822 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) 823 virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE], 824 vqs[i]); 825 826 virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE); 827 virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE); 828 829 err = 0; 830 831 out: 832 kfree(names); 833 kfree(callbacks); 834 kfree(vqs); 835 if (err) 836 virtscsi_remove_vqs(vdev); 837 return err; 838 } 839 840 static int virtscsi_probe(struct virtio_device *vdev) 841 { 842 struct Scsi_Host *shost; 843 struct virtio_scsi *vscsi; 844 int err; 845 u32 sg_elems, num_targets; 846 u32 cmd_per_lun; 847 u32 num_queues; 848 849 if (!vdev->config->get) { 850 dev_err(&vdev->dev, "%s failure: config access disabled\n", 851 __func__); 852 return -EINVAL; 853 } 854 855 /* We need to know how many queues before we allocate. */ 856 num_queues = virtscsi_config_get(vdev, num_queues) ? : 1; 857 858 num_targets = virtscsi_config_get(vdev, max_target) + 1; 859 860 shost = scsi_host_alloc(&virtscsi_host_template, 861 sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues); 862 if (!shost) 863 return -ENOMEM; 864 865 sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1; 866 shost->sg_tablesize = sg_elems; 867 vscsi = shost_priv(shost); 868 vscsi->vdev = vdev; 869 vscsi->num_queues = num_queues; 870 vdev->priv = shost; 871 872 err = virtscsi_init(vdev, vscsi); 873 if (err) 874 goto virtscsi_init_failed; 875 876 shost->can_queue = virtqueue_get_vring_size(vscsi->req_vqs[0].vq); 877 878 cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1; 879 shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue); 880 shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF; 881 882 /* LUNs > 256 are reported with format 1, so they go in the range 883 * 16640-32767. 884 */ 885 shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000; 886 shost->max_id = num_targets; 887 shost->max_channel = 0; 888 shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE; 889 shost->nr_hw_queues = num_queues; 890 891 #ifdef CONFIG_BLK_DEV_INTEGRITY 892 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) { 893 int host_prot; 894 895 host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION | 896 SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION | 897 SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION; 898 899 scsi_host_set_prot(shost, host_prot); 900 scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC); 901 } 902 #endif 903 904 err = scsi_add_host(shost, &vdev->dev); 905 if (err) 906 goto scsi_add_host_failed; 907 908 virtio_device_ready(vdev); 909 910 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) 911 virtscsi_kick_event_all(vscsi); 912 913 scsi_scan_host(shost); 914 return 0; 915 916 scsi_add_host_failed: 917 vdev->config->del_vqs(vdev); 918 virtscsi_init_failed: 919 scsi_host_put(shost); 920 return err; 921 } 922 923 static void virtscsi_remove(struct virtio_device *vdev) 924 { 925 struct Scsi_Host *shost = virtio_scsi_host(vdev); 926 struct virtio_scsi *vscsi = shost_priv(shost); 927 928 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) 929 virtscsi_cancel_event_work(vscsi); 930 931 scsi_remove_host(shost); 932 virtscsi_remove_vqs(vdev); 933 scsi_host_put(shost); 934 } 935 936 #ifdef CONFIG_PM_SLEEP 937 static int virtscsi_freeze(struct virtio_device *vdev) 938 { 939 virtscsi_remove_vqs(vdev); 940 return 0; 941 } 942 943 static int virtscsi_restore(struct virtio_device *vdev) 944 { 945 struct Scsi_Host *sh = virtio_scsi_host(vdev); 946 struct virtio_scsi *vscsi = shost_priv(sh); 947 int err; 948 949 err = virtscsi_init(vdev, vscsi); 950 if (err) 951 return err; 952 953 virtio_device_ready(vdev); 954 955 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) 956 virtscsi_kick_event_all(vscsi); 957 958 return err; 959 } 960 #endif 961 962 static struct virtio_device_id id_table[] = { 963 { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID }, 964 { 0 }, 965 }; 966 967 static unsigned int features[] = { 968 VIRTIO_SCSI_F_HOTPLUG, 969 VIRTIO_SCSI_F_CHANGE, 970 #ifdef CONFIG_BLK_DEV_INTEGRITY 971 VIRTIO_SCSI_F_T10_PI, 972 #endif 973 }; 974 975 static struct virtio_driver virtio_scsi_driver = { 976 .feature_table = features, 977 .feature_table_size = ARRAY_SIZE(features), 978 .driver.name = KBUILD_MODNAME, 979 .driver.owner = THIS_MODULE, 980 .id_table = id_table, 981 .probe = virtscsi_probe, 982 #ifdef CONFIG_PM_SLEEP 983 .freeze = virtscsi_freeze, 984 .restore = virtscsi_restore, 985 #endif 986 .remove = virtscsi_remove, 987 }; 988 989 static int __init init(void) 990 { 991 int ret = -ENOMEM; 992 993 virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0); 994 if (!virtscsi_cmd_cache) { 995 pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n"); 996 goto error; 997 } 998 999 1000 virtscsi_cmd_pool = 1001 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ, 1002 virtscsi_cmd_cache); 1003 if (!virtscsi_cmd_pool) { 1004 pr_err("mempool_create() for virtscsi_cmd_pool failed\n"); 1005 goto error; 1006 } 1007 ret = register_virtio_driver(&virtio_scsi_driver); 1008 if (ret < 0) 1009 goto error; 1010 1011 return 0; 1012 1013 error: 1014 if (virtscsi_cmd_pool) { 1015 mempool_destroy(virtscsi_cmd_pool); 1016 virtscsi_cmd_pool = NULL; 1017 } 1018 if (virtscsi_cmd_cache) { 1019 kmem_cache_destroy(virtscsi_cmd_cache); 1020 virtscsi_cmd_cache = NULL; 1021 } 1022 return ret; 1023 } 1024 1025 static void __exit fini(void) 1026 { 1027 unregister_virtio_driver(&virtio_scsi_driver); 1028 mempool_destroy(virtscsi_cmd_pool); 1029 kmem_cache_destroy(virtscsi_cmd_cache); 1030 } 1031 module_init(init); 1032 module_exit(fini); 1033 1034 MODULE_DEVICE_TABLE(virtio, id_table); 1035 MODULE_DESCRIPTION("Virtio SCSI HBA driver"); 1036 MODULE_LICENSE("GPL"); 1037