1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Virtio SCSI HBA driver
   4 *
   5 * Copyright IBM Corp. 2010
   6 * Copyright Red Hat, Inc. 2011
   7 *
   8 * Authors:
   9 *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.com>
  10 *  Paolo Bonzini   <pbonzini@redhat.com>
  11 */
  12
  13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15#include <linux/module.h>
  16#include <linux/slab.h>
  17#include <linux/mempool.h>
  18#include <linux/interrupt.h>
  19#include <linux/virtio.h>
  20#include <linux/virtio_ids.h>
  21#include <linux/virtio_config.h>
  22#include <linux/virtio_scsi.h>
  23#include <linux/cpu.h>
  24#include <linux/blkdev.h>
 
  25#include <scsi/scsi_host.h>
  26#include <scsi/scsi_device.h>
  27#include <scsi/scsi_cmnd.h>
  28#include <scsi/scsi_tcq.h>
  29#include <scsi/scsi_devinfo.h>
  30#include <linux/seqlock.h>
  31#include <linux/blk-mq-virtio.h>
  32
  33#include "sd.h"
  34
  35#define VIRTIO_SCSI_MEMPOOL_SZ 64
  36#define VIRTIO_SCSI_EVENT_LEN 8
  37#define VIRTIO_SCSI_VQ_BASE 2
  38
  39/* Command queue element */
  40struct virtio_scsi_cmd {
  41	struct scsi_cmnd *sc;
  42	struct completion *comp;
  43	union {
  44		struct virtio_scsi_cmd_req       cmd;
  45		struct virtio_scsi_cmd_req_pi    cmd_pi;
  46		struct virtio_scsi_ctrl_tmf_req  tmf;
  47		struct virtio_scsi_ctrl_an_req   an;
  48	} req;
  49	union {
  50		struct virtio_scsi_cmd_resp      cmd;
  51		struct virtio_scsi_ctrl_tmf_resp tmf;
  52		struct virtio_scsi_ctrl_an_resp  an;
  53		struct virtio_scsi_event         evt;
  54	} resp;
  55} ____cacheline_aligned_in_smp;
  56
  57struct virtio_scsi_event_node {
  58	struct virtio_scsi *vscsi;
  59	struct virtio_scsi_event event;
  60	struct work_struct work;
  61};
  62
  63struct virtio_scsi_vq {
  64	/* Protects vq */
  65	spinlock_t vq_lock;
  66
  67	struct virtqueue *vq;
  68};
  69
  70/* Driver instance state */
  71struct virtio_scsi {
  72	struct virtio_device *vdev;
  73
  74	/* Get some buffers ready for event vq */
  75	struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN];
  76
  77	u32 num_queues;
  78
  79	struct hlist_node node;
  80
  81	/* Protected by event_vq lock */
  82	bool stop_events;
  83
  84	struct virtio_scsi_vq ctrl_vq;
  85	struct virtio_scsi_vq event_vq;
  86	struct virtio_scsi_vq req_vqs[];
  87};
  88
  89static struct kmem_cache *virtscsi_cmd_cache;
  90static mempool_t *virtscsi_cmd_pool;
  91
  92static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
  93{
  94	return vdev->priv;
  95}
  96
  97static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
  98{
  99	if (resid)
 100		scsi_set_resid(sc, min(resid, scsi_bufflen(sc)));
 101}
 102
 103/*
 104 * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
 105 *
 106 * Called with vq_lock held.
 107 */
 108static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
 109{
 110	struct virtio_scsi_cmd *cmd = buf;
 111	struct scsi_cmnd *sc = cmd->sc;
 112	struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
 113
 114	dev_dbg(&sc->device->sdev_gendev,
 115		"cmd %p response %u status %#02x sense_len %u\n",
 116		sc, resp->response, resp->status, resp->sense_len);
 117
 118	sc->result = resp->status;
 119	virtscsi_compute_resid(sc, virtio32_to_cpu(vscsi->vdev, resp->resid));
 120	switch (resp->response) {
 121	case VIRTIO_SCSI_S_OK:
 122		set_host_byte(sc, DID_OK);
 123		break;
 124	case VIRTIO_SCSI_S_OVERRUN:
 125		set_host_byte(sc, DID_ERROR);
 126		break;
 127	case VIRTIO_SCSI_S_ABORTED:
 128		set_host_byte(sc, DID_ABORT);
 129		break;
 130	case VIRTIO_SCSI_S_BAD_TARGET:
 131		set_host_byte(sc, DID_BAD_TARGET);
 132		break;
 133	case VIRTIO_SCSI_S_RESET:
 134		set_host_byte(sc, DID_RESET);
 135		break;
 136	case VIRTIO_SCSI_S_BUSY:
 137		set_host_byte(sc, DID_BUS_BUSY);
 138		break;
 139	case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
 140		set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
 141		break;
 142	case VIRTIO_SCSI_S_TARGET_FAILURE:
 143		set_host_byte(sc, DID_TARGET_FAILURE);
 144		break;
 145	case VIRTIO_SCSI_S_NEXUS_FAILURE:
 146		set_host_byte(sc, DID_NEXUS_FAILURE);
 147		break;
 148	default:
 149		scmd_printk(KERN_WARNING, sc, "Unknown response %d",
 150			    resp->response);
 151		fallthrough;
 152	case VIRTIO_SCSI_S_FAILURE:
 153		set_host_byte(sc, DID_ERROR);
 154		break;
 155	}
 156
 157	WARN_ON(virtio32_to_cpu(vscsi->vdev, resp->sense_len) >
 158		VIRTIO_SCSI_SENSE_SIZE);
 159	if (resp->sense_len) {
 160		memcpy(sc->sense_buffer, resp->sense,
 161		       min_t(u32,
 162			     virtio32_to_cpu(vscsi->vdev, resp->sense_len),
 163			     VIRTIO_SCSI_SENSE_SIZE));
 164	}
 165
 166	sc->scsi_done(sc);
 167}
 168
 169static void virtscsi_vq_done(struct virtio_scsi *vscsi,
 170			     struct virtio_scsi_vq *virtscsi_vq,
 171			     void (*fn)(struct virtio_scsi *vscsi, void *buf))
 172{
 173	void *buf;
 174	unsigned int len;
 175	unsigned long flags;
 176	struct virtqueue *vq = virtscsi_vq->vq;
 177
 178	spin_lock_irqsave(&virtscsi_vq->vq_lock, flags);
 179	do {
 180		virtqueue_disable_cb(vq);
 181		while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
 182			fn(vscsi, buf);
 183
 184		if (unlikely(virtqueue_is_broken(vq)))
 185			break;
 186	} while (!virtqueue_enable_cb(vq));
 187	spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
 188}
 189
 190static void virtscsi_req_done(struct virtqueue *vq)
 191{
 192	struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 193	struct virtio_scsi *vscsi = shost_priv(sh);
 194	int index = vq->index - VIRTIO_SCSI_VQ_BASE;
 195	struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index];
 196
 197	virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd);
 198};
 199
 200static void virtscsi_poll_requests(struct virtio_scsi *vscsi)
 201{
 202	int i, num_vqs;
 203
 204	num_vqs = vscsi->num_queues;
 205	for (i = 0; i < num_vqs; i++)
 206		virtscsi_vq_done(vscsi, &vscsi->req_vqs[i],
 207				 virtscsi_complete_cmd);
 208}
 209
 210static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)
 211{
 212	struct virtio_scsi_cmd *cmd = buf;
 213
 214	if (cmd->comp)
 215		complete(cmd->comp);
 216}
 217
 218static void virtscsi_ctrl_done(struct virtqueue *vq)
 219{
 220	struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 221	struct virtio_scsi *vscsi = shost_priv(sh);
 222
 223	virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free);
 224};
 225
 226static void virtscsi_handle_event(struct work_struct *work);
 227
 228static int virtscsi_kick_event(struct virtio_scsi *vscsi,
 229			       struct virtio_scsi_event_node *event_node)
 230{
 231	int err;
 232	struct scatterlist sg;
 233	unsigned long flags;
 234
 235	INIT_WORK(&event_node->work, virtscsi_handle_event);
 236	sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
 237
 238	spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
 239
 240	err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node,
 241				  GFP_ATOMIC);
 242	if (!err)
 243		virtqueue_kick(vscsi->event_vq.vq);
 244
 245	spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
 246
 247	return err;
 248}
 249
 250static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
 251{
 252	int i;
 253
 254	for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
 255		vscsi->event_list[i].vscsi = vscsi;
 256		virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
 257	}
 258
 259	return 0;
 260}
 261
 262static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
 263{
 264	int i;
 265
 266	/* Stop scheduling work before calling cancel_work_sync.  */
 267	spin_lock_irq(&vscsi->event_vq.vq_lock);
 268	vscsi->stop_events = true;
 269	spin_unlock_irq(&vscsi->event_vq.vq_lock);
 270
 271	for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
 272		cancel_work_sync(&vscsi->event_list[i].work);
 273}
 274
 275static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
 276					    struct virtio_scsi_event *event)
 277{
 278	struct scsi_device *sdev;
 279	struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 280	unsigned int target = event->lun[1];
 281	unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 282
 283	switch (virtio32_to_cpu(vscsi->vdev, event->reason)) {
 284	case VIRTIO_SCSI_EVT_RESET_RESCAN:
 285		if (lun == 0) {
 286			scsi_scan_target(&shost->shost_gendev, 0, target,
 287					 SCAN_WILD_CARD, SCSI_SCAN_INITIAL);
 288		} else {
 289			scsi_add_device(shost, 0, target, lun);
 290		}
 291		break;
 292	case VIRTIO_SCSI_EVT_RESET_REMOVED:
 293		sdev = scsi_device_lookup(shost, 0, target, lun);
 294		if (sdev) {
 295			scsi_remove_device(sdev);
 296			scsi_device_put(sdev);
 297		} else {
 298			pr_err("SCSI device %d 0 %d %d not found\n",
 299				shost->host_no, target, lun);
 300		}
 301		break;
 302	default:
 303		pr_info("Unsupported virtio scsi event reason %x\n", event->reason);
 304	}
 305}
 306
 307static void virtscsi_handle_param_change(struct virtio_scsi *vscsi,
 308					 struct virtio_scsi_event *event)
 309{
 310	struct scsi_device *sdev;
 311	struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 312	unsigned int target = event->lun[1];
 313	unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 314	u8 asc = virtio32_to_cpu(vscsi->vdev, event->reason) & 255;
 315	u8 ascq = virtio32_to_cpu(vscsi->vdev, event->reason) >> 8;
 316
 317	sdev = scsi_device_lookup(shost, 0, target, lun);
 318	if (!sdev) {
 319		pr_err("SCSI device %d 0 %d %d not found\n",
 320			shost->host_no, target, lun);
 321		return;
 322	}
 323
 324	/* Handle "Parameters changed", "Mode parameters changed", and
 325	   "Capacity data has changed".  */
 326	if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
 327		scsi_rescan_device(&sdev->sdev_gendev);
 328
 329	scsi_device_put(sdev);
 330}
 331
 332static void virtscsi_rescan_hotunplug(struct virtio_scsi *vscsi)
 333{
 334	struct scsi_device *sdev;
 335	struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 336	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
 337	int result, inquiry_len, inq_result_len = 256;
 338	char *inq_result = kmalloc(inq_result_len, GFP_KERNEL);
 339
 340	shost_for_each_device(sdev, shost) {
 341		inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
 342
 343		memset(scsi_cmd, 0, sizeof(scsi_cmd));
 344		scsi_cmd[0] = INQUIRY;
 345		scsi_cmd[4] = (unsigned char) inquiry_len;
 346
 347		memset(inq_result, 0, inq_result_len);
 348
 349		result = scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE,
 350					  inq_result, inquiry_len, NULL,
 351					  SD_TIMEOUT, SD_MAX_RETRIES, NULL);
 352
 353		if (result == 0 && inq_result[0] >> 5) {
 354			/* PQ indicates the LUN is not attached */
 355			scsi_remove_device(sdev);
 356		} else if (result > 0 && host_byte(result) == DID_BAD_TARGET) {
 357			/*
 358			 * If all LUNs of a virtio-scsi device are unplugged
 359			 * it will respond with BAD TARGET on any INQUIRY
 360			 * command.
 361			 * Remove the device in this case as well.
 362			 */
 363			scsi_remove_device(sdev);
 364		}
 365	}
 366
 367	kfree(inq_result);
 368}
 369
 370static void virtscsi_handle_event(struct work_struct *work)
 371{
 372	struct virtio_scsi_event_node *event_node =
 373		container_of(work, struct virtio_scsi_event_node, work);
 374	struct virtio_scsi *vscsi = event_node->vscsi;
 375	struct virtio_scsi_event *event = &event_node->event;
 376
 377	if (event->event &
 378	    cpu_to_virtio32(vscsi->vdev, VIRTIO_SCSI_T_EVENTS_MISSED)) {
 379		event->event &= ~cpu_to_virtio32(vscsi->vdev,
 380						   VIRTIO_SCSI_T_EVENTS_MISSED);
 381		virtscsi_rescan_hotunplug(vscsi);
 382		scsi_scan_host(virtio_scsi_host(vscsi->vdev));
 383	}
 384
 385	switch (virtio32_to_cpu(vscsi->vdev, event->event)) {
 386	case VIRTIO_SCSI_T_NO_EVENT:
 387		break;
 388	case VIRTIO_SCSI_T_TRANSPORT_RESET:
 389		virtscsi_handle_transport_reset(vscsi, event);
 390		break;
 391	case VIRTIO_SCSI_T_PARAM_CHANGE:
 392		virtscsi_handle_param_change(vscsi, event);
 393		break;
 394	default:
 395		pr_err("Unsupported virtio scsi event %x\n", event->event);
 396	}
 397	virtscsi_kick_event(vscsi, event_node);
 398}
 399
 400static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf)
 401{
 402	struct virtio_scsi_event_node *event_node = buf;
 403
 404	if (!vscsi->stop_events)
 405		queue_work(system_freezable_wq, &event_node->work);
 406}
 407
 408static void virtscsi_event_done(struct virtqueue *vq)
 409{
 410	struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 411	struct virtio_scsi *vscsi = shost_priv(sh);
 412
 413	virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event);
 414};
 415
 416static int __virtscsi_add_cmd(struct virtqueue *vq,
 417			    struct virtio_scsi_cmd *cmd,
 418			    size_t req_size, size_t resp_size)
 419{
 420	struct scsi_cmnd *sc = cmd->sc;
 421	struct scatterlist *sgs[6], req, resp;
 422	struct sg_table *out, *in;
 423	unsigned out_num = 0, in_num = 0;
 424
 425	out = in = NULL;
 426
 427	if (sc && sc->sc_data_direction != DMA_NONE) {
 428		if (sc->sc_data_direction != DMA_FROM_DEVICE)
 429			out = &sc->sdb.table;
 430		if (sc->sc_data_direction != DMA_TO_DEVICE)
 431			in = &sc->sdb.table;
 432	}
 433
 434	/* Request header.  */
 435	sg_init_one(&req, &cmd->req, req_size);
 436	sgs[out_num++] = &req;
 437
 438	/* Data-out buffer.  */
 439	if (out) {
 440		/* Place WRITE protection SGLs before Data OUT payload */
 441		if (scsi_prot_sg_count(sc))
 442			sgs[out_num++] = scsi_prot_sglist(sc);
 443		sgs[out_num++] = out->sgl;
 444	}
 445
 446	/* Response header.  */
 447	sg_init_one(&resp, &cmd->resp, resp_size);
 448	sgs[out_num + in_num++] = &resp;
 449
 450	/* Data-in buffer */
 451	if (in) {
 452		/* Place READ protection SGLs before Data IN payload */
 453		if (scsi_prot_sg_count(sc))
 454			sgs[out_num + in_num++] = scsi_prot_sglist(sc);
 455		sgs[out_num + in_num++] = in->sgl;
 456	}
 457
 458	return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC);
 459}
 460
 461static void virtscsi_kick_vq(struct virtio_scsi_vq *vq)
 462{
 463	bool needs_kick;
 464	unsigned long flags;
 465
 466	spin_lock_irqsave(&vq->vq_lock, flags);
 467	needs_kick = virtqueue_kick_prepare(vq->vq);
 468	spin_unlock_irqrestore(&vq->vq_lock, flags);
 469
 470	if (needs_kick)
 471		virtqueue_notify(vq->vq);
 472}
 473
 474/**
 475 * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue, optionally kick it
 476 * @vq		: the struct virtqueue we're talking about
 477 * @cmd		: command structure
 478 * @req_size	: size of the request buffer
 479 * @resp_size	: size of the response buffer
 480 * @kick	: whether to kick the virtqueue immediately
 481 */
 482static int virtscsi_add_cmd(struct virtio_scsi_vq *vq,
 483			     struct virtio_scsi_cmd *cmd,
 484			     size_t req_size, size_t resp_size,
 485			     bool kick)
 486{
 487	unsigned long flags;
 488	int err;
 489	bool needs_kick = false;
 490
 491	spin_lock_irqsave(&vq->vq_lock, flags);
 492	err = __virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size);
 493	if (!err && kick)
 494		needs_kick = virtqueue_kick_prepare(vq->vq);
 495
 496	spin_unlock_irqrestore(&vq->vq_lock, flags);
 497
 498	if (needs_kick)
 499		virtqueue_notify(vq->vq);
 500	return err;
 501}
 502
 503static void virtio_scsi_init_hdr(struct virtio_device *vdev,
 504				 struct virtio_scsi_cmd_req *cmd,
 505				 struct scsi_cmnd *sc)
 506{
 507	cmd->lun[0] = 1;
 508	cmd->lun[1] = sc->device->id;
 509	cmd->lun[2] = (sc->device->lun >> 8) | 0x40;
 510	cmd->lun[3] = sc->device->lun & 0xff;
 511	cmd->tag = cpu_to_virtio64(vdev, (unsigned long)sc);
 512	cmd->task_attr = VIRTIO_SCSI_S_SIMPLE;
 513	cmd->prio = 0;
 514	cmd->crn = 0;
 515}
 516
 517#ifdef CONFIG_BLK_DEV_INTEGRITY
 518static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev,
 519				    struct virtio_scsi_cmd_req_pi *cmd_pi,
 520				    struct scsi_cmnd *sc)
 521{
 522	struct request *rq = sc->request;
 523	struct blk_integrity *bi;
 524
 525	virtio_scsi_init_hdr(vdev, (struct virtio_scsi_cmd_req *)cmd_pi, sc);
 526
 527	if (!rq || !scsi_prot_sg_count(sc))
 528		return;
 529
 530	bi = blk_get_integrity(rq->rq_disk);
 531
 532	if (sc->sc_data_direction == DMA_TO_DEVICE)
 533		cmd_pi->pi_bytesout = cpu_to_virtio32(vdev,
 534						      bio_integrity_bytes(bi,
 535							blk_rq_sectors(rq)));
 536	else if (sc->sc_data_direction == DMA_FROM_DEVICE)
 537		cmd_pi->pi_bytesin = cpu_to_virtio32(vdev,
 538						     bio_integrity_bytes(bi,
 539							blk_rq_sectors(rq)));
 540}
 541#endif
 542
 543static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi,
 544						  struct scsi_cmnd *sc)
 545{
 546	u32 tag = blk_mq_unique_tag(sc->request);
 547	u16 hwq = blk_mq_unique_tag_to_hwq(tag);
 548
 549	return &vscsi->req_vqs[hwq];
 550}
 551
 552static int virtscsi_queuecommand(struct Scsi_Host *shost,
 553				 struct scsi_cmnd *sc)
 554{
 555	struct virtio_scsi *vscsi = shost_priv(shost);
 556	struct virtio_scsi_vq *req_vq = virtscsi_pick_vq_mq(vscsi, sc);
 557	struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
 558	bool kick;
 559	unsigned long flags;
 560	int req_size;
 561	int ret;
 562
 563	BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
 564
 565	/* TODO: check feature bit and fail if unsupported?  */
 566	BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
 567
 568	dev_dbg(&sc->device->sdev_gendev,
 569		"cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
 570
 571	cmd->sc = sc;
 572
 573	BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
 574
 575#ifdef CONFIG_BLK_DEV_INTEGRITY
 576	if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) {
 577		virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, sc);
 578		memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len);
 579		req_size = sizeof(cmd->req.cmd_pi);
 580	} else
 581#endif
 582	{
 583		virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, sc);
 584		memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
 585		req_size = sizeof(cmd->req.cmd);
 586	}
 587
 588	kick = (sc->flags & SCMD_LAST) != 0;
 589	ret = virtscsi_add_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd), kick);
 590	if (ret == -EIO) {
 591		cmd->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
 592		spin_lock_irqsave(&req_vq->vq_lock, flags);
 593		virtscsi_complete_cmd(vscsi, cmd);
 594		spin_unlock_irqrestore(&req_vq->vq_lock, flags);
 595	} else if (ret != 0) {
 596		return SCSI_MLQUEUE_HOST_BUSY;
 597	}
 598	return 0;
 599}
 600
 601static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
 602{
 603	DECLARE_COMPLETION_ONSTACK(comp);
 604	int ret = FAILED;
 605
 606	cmd->comp = &comp;
 607	if (virtscsi_add_cmd(&vscsi->ctrl_vq, cmd,
 608			      sizeof cmd->req.tmf, sizeof cmd->resp.tmf, true) < 0)
 609		goto out;
 610
 611	wait_for_completion(&comp);
 612	if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
 613	    cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
 614		ret = SUCCESS;
 615
 616	/*
 617	 * The spec guarantees that all requests related to the TMF have
 618	 * been completed, but the callback might not have run yet if
 619	 * we're using independent interrupts (e.g. MSI).  Poll the
 620	 * virtqueues once.
 621	 *
 622	 * In the abort case, sc->scsi_done will do nothing, because
 623	 * the block layer must have detected a timeout and as a result
 624	 * REQ_ATOM_COMPLETE has been set.
 625	 */
 626	virtscsi_poll_requests(vscsi);
 627
 628out:
 629	mempool_free(cmd, virtscsi_cmd_pool);
 630	return ret;
 631}
 632
 633static int virtscsi_device_reset(struct scsi_cmnd *sc)
 634{
 635	struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 636	struct virtio_scsi_cmd *cmd;
 637
 638	sdev_printk(KERN_INFO, sc->device, "device reset\n");
 639	cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 640	if (!cmd)
 641		return FAILED;
 642
 643	memset(cmd, 0, sizeof(*cmd));
 644	cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 645		.type = VIRTIO_SCSI_T_TMF,
 646		.subtype = cpu_to_virtio32(vscsi->vdev,
 647					     VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET),
 648		.lun[0] = 1,
 649		.lun[1] = sc->device->id,
 650		.lun[2] = (sc->device->lun >> 8) | 0x40,
 651		.lun[3] = sc->device->lun & 0xff,
 652	};
 653	return virtscsi_tmf(vscsi, cmd);
 654}
 655
 656static int virtscsi_device_alloc(struct scsi_device *sdevice)
 657{
 658	/*
 659	 * Passed through SCSI targets (e.g. with qemu's 'scsi-block')
 660	 * may have transfer limits which come from the host SCSI
 661	 * controller or something on the host side other than the
 662	 * target itself.
 663	 *
 664	 * To make this work properly, the hypervisor can adjust the
 665	 * target's VPD information to advertise these limits.  But
 666	 * for that to work, the guest has to look at the VPD pages,
 667	 * which we won't do by default if it is an SPC-2 device, even
 668	 * if it does actually support it.
 669	 *
 670	 * So, set the blist to always try to read the VPD pages.
 671	 */
 672	sdevice->sdev_bflags = BLIST_TRY_VPD_PAGES;
 673
 674	return 0;
 675}
 676
 677
 678/**
 679 * virtscsi_change_queue_depth() - Change a virtscsi target's queue depth
 680 * @sdev:	Virtscsi target whose queue depth to change
 681 * @qdepth:	New queue depth
 682 */
 683static int virtscsi_change_queue_depth(struct scsi_device *sdev, int qdepth)
 684{
 685	struct Scsi_Host *shost = sdev->host;
 686	int max_depth = shost->cmd_per_lun;
 687
 688	return scsi_change_queue_depth(sdev, min(max_depth, qdepth));
 689}
 690
 691static int virtscsi_abort(struct scsi_cmnd *sc)
 692{
 693	struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 694	struct virtio_scsi_cmd *cmd;
 695
 696	scmd_printk(KERN_INFO, sc, "abort\n");
 697	cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 698	if (!cmd)
 699		return FAILED;
 700
 701	memset(cmd, 0, sizeof(*cmd));
 702	cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 703		.type = VIRTIO_SCSI_T_TMF,
 704		.subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
 705		.lun[0] = 1,
 706		.lun[1] = sc->device->id,
 707		.lun[2] = (sc->device->lun >> 8) | 0x40,
 708		.lun[3] = sc->device->lun & 0xff,
 709		.tag = cpu_to_virtio64(vscsi->vdev, (unsigned long)sc),
 710	};
 711	return virtscsi_tmf(vscsi, cmd);
 712}
 713
 714static int virtscsi_map_queues(struct Scsi_Host *shost)
 715{
 716	struct virtio_scsi *vscsi = shost_priv(shost);
 717	struct blk_mq_queue_map *qmap = &shost->tag_set.map[HCTX_TYPE_DEFAULT];
 718
 719	return blk_mq_virtio_map_queues(qmap, vscsi->vdev, 2);
 720}
 721
 722static void virtscsi_commit_rqs(struct Scsi_Host *shost, u16 hwq)
 723{
 724	struct virtio_scsi *vscsi = shost_priv(shost);
 725
 726	virtscsi_kick_vq(&vscsi->req_vqs[hwq]);
 727}
 728
 729/*
 730 * The host guarantees to respond to each command, although I/O
 731 * latencies might be higher than on bare metal.  Reset the timer
 732 * unconditionally to give the host a chance to perform EH.
 733 */
 734static enum blk_eh_timer_return virtscsi_eh_timed_out(struct scsi_cmnd *scmnd)
 735{
 736	return BLK_EH_RESET_TIMER;
 737}
 738
 739static struct scsi_host_template virtscsi_host_template = {
 740	.module = THIS_MODULE,
 741	.name = "Virtio SCSI HBA",
 742	.proc_name = "virtio_scsi",
 743	.this_id = -1,
 744	.cmd_size = sizeof(struct virtio_scsi_cmd),
 745	.queuecommand = virtscsi_queuecommand,
 746	.commit_rqs = virtscsi_commit_rqs,
 747	.change_queue_depth = virtscsi_change_queue_depth,
 748	.eh_abort_handler = virtscsi_abort,
 749	.eh_device_reset_handler = virtscsi_device_reset,
 750	.eh_timed_out = virtscsi_eh_timed_out,
 751	.slave_alloc = virtscsi_device_alloc,
 752
 753	.dma_boundary = UINT_MAX,
 754	.map_queues = virtscsi_map_queues,
 755	.track_queue_depth = 1,
 756};
 757
 758#define virtscsi_config_get(vdev, fld) \
 759	({ \
 760		__virtio_native_type(struct virtio_scsi_config, fld) __val; \
 761		virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \
 762		__val; \
 763	})
 764
 765#define virtscsi_config_set(vdev, fld, val) \
 766	do { \
 767		__virtio_native_type(struct virtio_scsi_config, fld) __val = (val); \
 768		virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \
 769	} while(0)
 770
 771static 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
 778static 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
 785static int virtscsi_init(struct virtio_device *vdev,
 786			 struct virtio_scsi *vscsi)
 787{
 788	int err;
 789	u32 i;
 790	u32 num_vqs;
 791	vq_callback_t **callbacks;
 792	const char **names;
 793	struct virtqueue **vqs;
 794	struct irq_affinity desc = { .pre_vectors = 2 };
 795
 796	num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;
 797	vqs = kmalloc_array(num_vqs, sizeof(struct virtqueue *), GFP_KERNEL);
 798	callbacks = kmalloc_array(num_vqs, sizeof(vq_callback_t *),
 799				  GFP_KERNEL);
 800	names = kmalloc_array(num_vqs, sizeof(char *), GFP_KERNEL);
 801
 802	if (!callbacks || !vqs || !names) {
 803		err = -ENOMEM;
 804		goto out;
 805	}
 806
 807	callbacks[0] = virtscsi_ctrl_done;
 808	callbacks[1] = virtscsi_event_done;
 809	names[0] = "control";
 810	names[1] = "event";
 811	for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) {
 812		callbacks[i] = virtscsi_req_done;
 813		names[i] = "request";
 814	}
 815
 816	/* Discover virtqueues and write information to configuration.  */
 817	err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc);
 818	if (err)
 819		goto out;
 820
 821	virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
 822	virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
 823	for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
 824		virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
 825				 vqs[i]);
 826
 827	virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
 828	virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
 829
 830	err = 0;
 831
 832out:
 833	kfree(names);
 834	kfree(callbacks);
 835	kfree(vqs);
 836	if (err)
 837		virtscsi_remove_vqs(vdev);
 838	return err;
 839}
 840
 841static int virtscsi_probe(struct virtio_device *vdev)
 842{
 843	struct Scsi_Host *shost;
 844	struct virtio_scsi *vscsi;
 845	int err;
 846	u32 sg_elems, num_targets;
 847	u32 cmd_per_lun;
 848	u32 num_queues;
 849
 850	if (!vdev->config->get) {
 851		dev_err(&vdev->dev, "%s failure: config access disabled\n",
 852			__func__);
 853		return -EINVAL;
 854	}
 855
 856	/* We need to know how many queues before we allocate. */
 857	num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
 858	num_queues = min_t(unsigned int, nr_cpu_ids, num_queues);
 859
 860	num_targets = virtscsi_config_get(vdev, max_target) + 1;
 861
 862	shost = scsi_host_alloc(&virtscsi_host_template,
 863				struct_size(vscsi, req_vqs, num_queues));
 864	if (!shost)
 865		return -ENOMEM;
 866
 867	sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
 868	shost->sg_tablesize = sg_elems;
 869	vscsi = shost_priv(shost);
 870	vscsi->vdev = vdev;
 871	vscsi->num_queues = num_queues;
 872	vdev->priv = shost;
 873
 874	err = virtscsi_init(vdev, vscsi);
 875	if (err)
 876		goto virtscsi_init_failed;
 877
 878	shost->can_queue = virtqueue_get_vring_size(vscsi->req_vqs[0].vq);
 879
 880	cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
 881	shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
 882	shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
 883
 884	/* LUNs > 256 are reported with format 1, so they go in the range
 885	 * 16640-32767.
 886	 */
 887	shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
 888	shost->max_id = num_targets;
 889	shost->max_channel = 0;
 890	shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
 891	shost->nr_hw_queues = num_queues;
 892
 893#ifdef CONFIG_BLK_DEV_INTEGRITY
 894	if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
 895		int host_prot;
 896
 897		host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
 898			    SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
 899			    SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
 900
 901		scsi_host_set_prot(shost, host_prot);
 902		scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC);
 903	}
 904#endif
 905
 906	err = scsi_add_host(shost, &vdev->dev);
 907	if (err)
 908		goto scsi_add_host_failed;
 909
 910	virtio_device_ready(vdev);
 911
 912	if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 913		virtscsi_kick_event_all(vscsi);
 914
 915	scsi_scan_host(shost);
 916	return 0;
 917
 918scsi_add_host_failed:
 919	vdev->config->del_vqs(vdev);
 920virtscsi_init_failed:
 921	scsi_host_put(shost);
 922	return err;
 923}
 924
 925static void virtscsi_remove(struct virtio_device *vdev)
 926{
 927	struct Scsi_Host *shost = virtio_scsi_host(vdev);
 928	struct virtio_scsi *vscsi = shost_priv(shost);
 929
 930	if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 931		virtscsi_cancel_event_work(vscsi);
 932
 933	scsi_remove_host(shost);
 934	virtscsi_remove_vqs(vdev);
 935	scsi_host_put(shost);
 936}
 937
 938#ifdef CONFIG_PM_SLEEP
 939static int virtscsi_freeze(struct virtio_device *vdev)
 940{
 941	virtscsi_remove_vqs(vdev);
 942	return 0;
 943}
 944
 945static int virtscsi_restore(struct virtio_device *vdev)
 946{
 947	struct Scsi_Host *sh = virtio_scsi_host(vdev);
 948	struct virtio_scsi *vscsi = shost_priv(sh);
 949	int err;
 950
 951	err = virtscsi_init(vdev, vscsi);
 952	if (err)
 953		return err;
 954
 955	virtio_device_ready(vdev);
 956
 957	if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 958		virtscsi_kick_event_all(vscsi);
 959
 960	return err;
 961}
 962#endif
 963
 964static struct virtio_device_id id_table[] = {
 965	{ VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
 966	{ 0 },
 967};
 968
 969static unsigned int features[] = {
 970	VIRTIO_SCSI_F_HOTPLUG,
 971	VIRTIO_SCSI_F_CHANGE,
 972#ifdef CONFIG_BLK_DEV_INTEGRITY
 973	VIRTIO_SCSI_F_T10_PI,
 974#endif
 975};
 976
 977static struct virtio_driver virtio_scsi_driver = {
 978	.feature_table = features,
 979	.feature_table_size = ARRAY_SIZE(features),
 980	.driver.name = KBUILD_MODNAME,
 981	.driver.owner = THIS_MODULE,
 982	.id_table = id_table,
 983	.probe = virtscsi_probe,
 984#ifdef CONFIG_PM_SLEEP
 985	.freeze = virtscsi_freeze,
 986	.restore = virtscsi_restore,
 987#endif
 988	.remove = virtscsi_remove,
 989};
 990
 991static int __init init(void)
 992{
 993	int ret = -ENOMEM;
 994
 995	virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
 996	if (!virtscsi_cmd_cache) {
 997		pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
 998		goto error;
 999	}
1000
1001
1002	virtscsi_cmd_pool =
1003		mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
1004					 virtscsi_cmd_cache);
1005	if (!virtscsi_cmd_pool) {
1006		pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
1007		goto error;
1008	}
1009	ret = register_virtio_driver(&virtio_scsi_driver);
1010	if (ret < 0)
1011		goto error;
1012
1013	return 0;
1014
1015error:
1016	mempool_destroy(virtscsi_cmd_pool);
1017	virtscsi_cmd_pool = NULL;
1018	kmem_cache_destroy(virtscsi_cmd_cache);
1019	virtscsi_cmd_cache = NULL;
1020	return ret;
1021}
1022
1023static void __exit fini(void)
1024{
1025	unregister_virtio_driver(&virtio_scsi_driver);
1026	mempool_destroy(virtscsi_cmd_pool);
1027	kmem_cache_destroy(virtscsi_cmd_cache);
1028}
1029module_init(init);
1030module_exit(fini);
1031
1032MODULE_DEVICE_TABLE(virtio, id_table);
1033MODULE_DESCRIPTION("Virtio SCSI HBA driver");
1034MODULE_LICENSE("GPL");