virtio_scsi.c

   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 <linux/blk-integrity.h>
  26#include <scsi/scsi_host.h>
  27#include <scsi/scsi_device.h>
  28#include <scsi/scsi_cmnd.h>
  29#include <scsi/scsi_tcq.h>
  30#include <scsi/scsi_devinfo.h>
  31#include <linux/seqlock.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
  39static unsigned int virtscsi_poll_queues;
  40module_param(virtscsi_poll_queues, uint, 0644);
  41MODULE_PARM_DESC(virtscsi_poll_queues,
  42		 "The number of dedicated virtqueues for polling I/O");
  43
  44/* Command queue element */
  45struct virtio_scsi_cmd {
  46	struct scsi_cmnd *sc;
  47	struct completion *comp;
  48	union {
  49		struct virtio_scsi_cmd_req       cmd;
  50		struct virtio_scsi_cmd_req_pi    cmd_pi;
  51		struct virtio_scsi_ctrl_tmf_req  tmf;
  52		struct virtio_scsi_ctrl_an_req   an;
  53	} req;
  54	union {
  55		struct virtio_scsi_cmd_resp      cmd;
  56		struct virtio_scsi_ctrl_tmf_resp tmf;
  57		struct virtio_scsi_ctrl_an_resp  an;
  58		struct virtio_scsi_event         evt;
  59	} resp;
  60} ____cacheline_aligned_in_smp;
  61
  62struct virtio_scsi_event_node {
  63	struct virtio_scsi *vscsi;
  64	struct virtio_scsi_event event;
  65	struct work_struct work;
  66};
  67
  68struct virtio_scsi_vq {
  69	/* Protects vq */
  70	spinlock_t vq_lock;
  71
  72	struct virtqueue *vq;
  73};
  74
  75/* Driver instance state */
  76struct virtio_scsi {
  77	struct virtio_device *vdev;
  78
  79	/* Get some buffers ready for event vq */
  80	struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN];
  81
  82	u32 num_queues;
  83	int io_queues[HCTX_MAX_TYPES];
  84
  85	struct hlist_node node;
  86
  87	/* Protected by event_vq lock */
  88	bool stop_events;
  89
  90	struct virtio_scsi_vq ctrl_vq;
  91	struct virtio_scsi_vq event_vq;
  92	struct virtio_scsi_vq req_vqs[];
  93};
  94
  95static struct kmem_cache *virtscsi_cmd_cache;
  96static mempool_t *virtscsi_cmd_pool;
  97
  98static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
  99{
 100	return vdev->priv;
 101}
 102
 103static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
 104{
 105	if (resid)
 106		scsi_set_resid(sc, min(resid, scsi_bufflen(sc)));
 107}
 108
 109/*
 110 * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
 111 *
 112 * Called with vq_lock held.
 113 */
 114static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
 115{
 116	struct virtio_scsi_cmd *cmd = buf;
 117	struct scsi_cmnd *sc = cmd->sc;
 118	struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
 119
 120	dev_dbg(&sc->device->sdev_gendev,
 121		"cmd %p response %u status %#02x sense_len %u\n",
 122		sc, resp->response, resp->status, resp->sense_len);
 123
 124	sc->result = resp->status;
 125	virtscsi_compute_resid(sc, virtio32_to_cpu(vscsi->vdev, resp->resid));
 126	switch (resp->response) {
 127	case VIRTIO_SCSI_S_OK:
 128		set_host_byte(sc, DID_OK);
 129		break;
 130	case VIRTIO_SCSI_S_OVERRUN:
 131		set_host_byte(sc, DID_ERROR);
 132		break;
 133	case VIRTIO_SCSI_S_ABORTED:
 134		set_host_byte(sc, DID_ABORT);
 135		break;
 136	case VIRTIO_SCSI_S_BAD_TARGET:
 137		set_host_byte(sc, DID_BAD_TARGET);
 138		break;
 139	case VIRTIO_SCSI_S_RESET:
 140		set_host_byte(sc, DID_RESET);
 141		break;
 142	case VIRTIO_SCSI_S_BUSY:
 143		set_host_byte(sc, DID_BUS_BUSY);
 144		break;
 145	case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
 146		set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
 147		break;
 148	case VIRTIO_SCSI_S_TARGET_FAILURE:
 149		set_host_byte(sc, DID_BAD_TARGET);
 150		break;
 151	case VIRTIO_SCSI_S_NEXUS_FAILURE:
 152		set_status_byte(sc, SAM_STAT_RESERVATION_CONFLICT);
 153		break;
 154	default:
 155		scmd_printk(KERN_WARNING, sc, "Unknown response %d",
 156			    resp->response);
 157		fallthrough;
 158	case VIRTIO_SCSI_S_FAILURE:
 159		set_host_byte(sc, DID_ERROR);
 160		break;
 161	}
 162
 163	WARN_ON(virtio32_to_cpu(vscsi->vdev, resp->sense_len) >
 164		VIRTIO_SCSI_SENSE_SIZE);
 165	if (resp->sense_len) {
 166		memcpy(sc->sense_buffer, resp->sense,
 167		       min_t(u32,
 168			     virtio32_to_cpu(vscsi->vdev, resp->sense_len),
 169			     VIRTIO_SCSI_SENSE_SIZE));
 170	}
 171
 172	scsi_done(sc);
 173}
 174
 175static void virtscsi_vq_done(struct virtio_scsi *vscsi,
 176			     struct virtio_scsi_vq *virtscsi_vq,
 177			     void (*fn)(struct virtio_scsi *vscsi, void *buf))
 178{
 179	void *buf;
 180	unsigned int len;
 181	unsigned long flags;
 182	struct virtqueue *vq = virtscsi_vq->vq;
 183
 184	spin_lock_irqsave(&virtscsi_vq->vq_lock, flags);
 185	do {
 186		virtqueue_disable_cb(vq);
 187		while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
 188			fn(vscsi, buf);
 189
 190	} while (!virtqueue_enable_cb(vq));
 191	spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
 192}
 193
 194static void virtscsi_req_done(struct virtqueue *vq)
 195{
 196	struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 197	struct virtio_scsi *vscsi = shost_priv(sh);
 198	int index = vq->index - VIRTIO_SCSI_VQ_BASE;
 199	struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index];
 200
 201	virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd);
 202};
 203
 204static void virtscsi_poll_requests(struct virtio_scsi *vscsi)
 205{
 206	int i, num_vqs;
 207
 208	num_vqs = vscsi->num_queues;
 209	for (i = 0; i < num_vqs; i++)
 210		virtscsi_vq_done(vscsi, &vscsi->req_vqs[i],
 211				 virtscsi_complete_cmd);
 212}
 213
 214static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)
 215{
 216	struct virtio_scsi_cmd *cmd = buf;
 217
 218	if (cmd->comp)
 219		complete(cmd->comp);
 220}
 221
 222static void virtscsi_ctrl_done(struct virtqueue *vq)
 223{
 224	struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 225	struct virtio_scsi *vscsi = shost_priv(sh);
 226
 227	virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free);
 228};
 229
 230static void virtscsi_handle_event(struct work_struct *work);
 231
 232static int virtscsi_kick_event(struct virtio_scsi *vscsi,
 233			       struct virtio_scsi_event_node *event_node)
 234{
 235	int err;
 236	struct scatterlist sg;
 237	unsigned long flags;
 238
 239	INIT_WORK(&event_node->work, virtscsi_handle_event);
 240	sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
 241
 242	spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
 243
 244	err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node,
 245				  GFP_ATOMIC);
 246	if (!err)
 247		virtqueue_kick(vscsi->event_vq.vq);
 248
 249	spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
 250
 251	return err;
 252}
 253
 254static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
 255{
 256	int i;
 257
 258	for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
 259		vscsi->event_list[i].vscsi = vscsi;
 260		virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
 261	}
 262
 263	return 0;
 264}
 265
 266static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
 267{
 268	int i;
 269
 270	/* Stop scheduling work before calling cancel_work_sync.  */
 271	spin_lock_irq(&vscsi->event_vq.vq_lock);
 272	vscsi->stop_events = true;
 273	spin_unlock_irq(&vscsi->event_vq.vq_lock);
 274
 275	for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
 276		cancel_work_sync(&vscsi->event_list[i].work);
 277}
 278
 279static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
 280					    struct virtio_scsi_event *event)
 281{
 282	struct scsi_device *sdev;
 283	struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 284	unsigned int target = event->lun[1];
 285	unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 286
 287	switch (virtio32_to_cpu(vscsi->vdev, event->reason)) {
 288	case VIRTIO_SCSI_EVT_RESET_RESCAN:
 289		if (lun == 0) {
 290			scsi_scan_target(&shost->shost_gendev, 0, target,
 291					 SCAN_WILD_CARD, SCSI_SCAN_INITIAL);
 292		} else {
 293			scsi_add_device(shost, 0, target, lun);
 294		}
 295		break;
 296	case VIRTIO_SCSI_EVT_RESET_REMOVED:
 297		sdev = scsi_device_lookup(shost, 0, target, lun);
 298		if (sdev) {
 299			scsi_remove_device(sdev);
 300			scsi_device_put(sdev);
 301		} else {
 302			pr_err("SCSI device %d 0 %d %d not found\n",
 303				shost->host_no, target, lun);
 304		}
 305		break;
 306	default:
 307		pr_info("Unsupported virtio scsi event reason %x\n", event->reason);
 308	}
 309}
 310
 311static void virtscsi_handle_param_change(struct virtio_scsi *vscsi,
 312					 struct virtio_scsi_event *event)
 313{
 314	struct scsi_device *sdev;
 315	struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 316	unsigned int target = event->lun[1];
 317	unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 318	u8 asc = virtio32_to_cpu(vscsi->vdev, event->reason) & 255;
 319	u8 ascq = virtio32_to_cpu(vscsi->vdev, event->reason) >> 8;
 320
 321	sdev = scsi_device_lookup(shost, 0, target, lun);
 322	if (!sdev) {
 323		pr_err("SCSI device %d 0 %d %d not found\n",
 324			shost->host_no, target, lun);
 325		return;
 326	}
 327
 328	/* Handle "Parameters changed", "Mode parameters changed", and
 329	   "Capacity data has changed".  */
 330	if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
 331		scsi_rescan_device(sdev);
 332
 333	scsi_device_put(sdev);
 334}
 335
 336static int virtscsi_rescan_hotunplug(struct virtio_scsi *vscsi)
 337{
 338	struct scsi_device *sdev;
 339	struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 340	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
 341	int result, inquiry_len, inq_result_len = 256;
 342	char *inq_result = kmalloc(inq_result_len, GFP_KERNEL);
 343
 344	if (!inq_result)
 345		return -ENOMEM;
 346
 347	shost_for_each_device(sdev, shost) {
 348		inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
 349
 350		memset(scsi_cmd, 0, sizeof(scsi_cmd));
 351		scsi_cmd[0] = INQUIRY;
 352		scsi_cmd[4] = (unsigned char) inquiry_len;
 353
 354		memset(inq_result, 0, inq_result_len);
 355
 356		result = scsi_execute_cmd(sdev, scsi_cmd, REQ_OP_DRV_IN,
 357					  inq_result, inquiry_len,
 358					  SD_TIMEOUT, SD_MAX_RETRIES, NULL);
 359
 360		if (result == 0 && inq_result[0] >> 5) {
 361			/* PQ indicates the LUN is not attached */
 362			scsi_remove_device(sdev);
 363		} else if (result > 0 && host_byte(result) == DID_BAD_TARGET) {
 364			/*
 365			 * If all LUNs of a virtio-scsi device are unplugged
 366			 * it will respond with BAD TARGET on any INQUIRY
 367			 * command.
 368			 * Remove the device in this case as well.
 369			 */
 370			scsi_remove_device(sdev);
 371		}
 372	}
 373
 374	kfree(inq_result);
 375	return 0;
 376}
 377
 378static void virtscsi_handle_event(struct work_struct *work)
 379{
 380	struct virtio_scsi_event_node *event_node =
 381		container_of(work, struct virtio_scsi_event_node, work);
 382	struct virtio_scsi *vscsi = event_node->vscsi;
 383	struct virtio_scsi_event *event = &event_node->event;
 384
 385	if (event->event &
 386	    cpu_to_virtio32(vscsi->vdev, VIRTIO_SCSI_T_EVENTS_MISSED)) {
 387		int ret;
 388
 389		event->event &= ~cpu_to_virtio32(vscsi->vdev,
 390						   VIRTIO_SCSI_T_EVENTS_MISSED);
 391		ret = virtscsi_rescan_hotunplug(vscsi);
 392		if (ret)
 393			return;
 394		scsi_scan_host(virtio_scsi_host(vscsi->vdev));
 395	}
 396
 397	switch (virtio32_to_cpu(vscsi->vdev, event->event)) {
 398	case VIRTIO_SCSI_T_NO_EVENT:
 399		break;
 400	case VIRTIO_SCSI_T_TRANSPORT_RESET:
 401		virtscsi_handle_transport_reset(vscsi, event);
 402		break;
 403	case VIRTIO_SCSI_T_PARAM_CHANGE:
 404		virtscsi_handle_param_change(vscsi, event);
 405		break;
 406	default:
 407		pr_err("Unsupported virtio scsi event %x\n", event->event);
 408	}
 409	virtscsi_kick_event(vscsi, event_node);
 410}
 411
 412static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf)
 413{
 414	struct virtio_scsi_event_node *event_node = buf;
 415
 416	if (!vscsi->stop_events)
 417		queue_work(system_freezable_wq, &event_node->work);
 418}
 419
 420static void virtscsi_event_done(struct virtqueue *vq)
 421{
 422	struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 423	struct virtio_scsi *vscsi = shost_priv(sh);
 424
 425	virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event);
 426};
 427
 428static int __virtscsi_add_cmd(struct virtqueue *vq,
 429			    struct virtio_scsi_cmd *cmd,
 430			    size_t req_size, size_t resp_size)
 431{
 432	struct scsi_cmnd *sc = cmd->sc;
 433	struct scatterlist *sgs[6], req, resp;
 434	struct sg_table *out, *in;
 435	unsigned out_num = 0, in_num = 0;
 436
 437	out = in = NULL;
 438
 439	if (sc && sc->sc_data_direction != DMA_NONE) {
 440		if (sc->sc_data_direction != DMA_FROM_DEVICE)
 441			out = &sc->sdb.table;
 442		if (sc->sc_data_direction != DMA_TO_DEVICE)
 443			in = &sc->sdb.table;
 444	}
 445
 446	/* Request header.  */
 447	sg_init_one(&req, &cmd->req, req_size);
 448	sgs[out_num++] = &req;
 449
 450	/* Data-out buffer.  */
 451	if (out) {
 452		/* Place WRITE protection SGLs before Data OUT payload */
 453		if (scsi_prot_sg_count(sc))
 454			sgs[out_num++] = scsi_prot_sglist(sc);
 455		sgs[out_num++] = out->sgl;
 456	}
 457
 458	/* Response header.  */
 459	sg_init_one(&resp, &cmd->resp, resp_size);
 460	sgs[out_num + in_num++] = &resp;
 461
 462	/* Data-in buffer */
 463	if (in) {
 464		/* Place READ protection SGLs before Data IN payload */
 465		if (scsi_prot_sg_count(sc))
 466			sgs[out_num + in_num++] = scsi_prot_sglist(sc);
 467		sgs[out_num + in_num++] = in->sgl;
 468	}
 469
 470	return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC);
 471}
 472
 473static void virtscsi_kick_vq(struct virtio_scsi_vq *vq)
 474{
 475	bool needs_kick;
 476	unsigned long flags;
 477
 478	spin_lock_irqsave(&vq->vq_lock, flags);
 479	needs_kick = virtqueue_kick_prepare(vq->vq);
 480	spin_unlock_irqrestore(&vq->vq_lock, flags);
 481
 482	if (needs_kick)
 483		virtqueue_notify(vq->vq);
 484}
 485
 486/**
 487 * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue, optionally kick it
 488 * @vq		: the struct virtqueue we're talking about
 489 * @cmd		: command structure
 490 * @req_size	: size of the request buffer
 491 * @resp_size	: size of the response buffer
 492 * @kick	: whether to kick the virtqueue immediately
 493 */
 494static int virtscsi_add_cmd(struct virtio_scsi_vq *vq,
 495			     struct virtio_scsi_cmd *cmd,
 496			     size_t req_size, size_t resp_size,
 497			     bool kick)
 498{
 499	unsigned long flags;
 500	int err;
 501	bool needs_kick = false;
 502
 503	spin_lock_irqsave(&vq->vq_lock, flags);
 504	err = __virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size);
 505	if (!err && kick)
 506		needs_kick = virtqueue_kick_prepare(vq->vq);
 507
 508	spin_unlock_irqrestore(&vq->vq_lock, flags);
 509
 510	if (needs_kick)
 511		virtqueue_notify(vq->vq);
 512	return err;
 513}
 514
 515static void virtio_scsi_init_hdr(struct virtio_device *vdev,
 516				 struct virtio_scsi_cmd_req *cmd,
 517				 struct scsi_cmnd *sc)
 518{
 519	cmd->lun[0] = 1;
 520	cmd->lun[1] = sc->device->id;
 521	cmd->lun[2] = (sc->device->lun >> 8) | 0x40;
 522	cmd->lun[3] = sc->device->lun & 0xff;
 523	cmd->tag = cpu_to_virtio64(vdev, (unsigned long)sc);
 524	cmd->task_attr = VIRTIO_SCSI_S_SIMPLE;
 525	cmd->prio = 0;
 526	cmd->crn = 0;
 527}
 528
 529#ifdef CONFIG_BLK_DEV_INTEGRITY
 530static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev,
 531				    struct virtio_scsi_cmd_req_pi *cmd_pi,
 532				    struct scsi_cmnd *sc)
 533{
 534	struct request *rq = scsi_cmd_to_rq(sc);
 535	struct blk_integrity *bi;
 536
 537	virtio_scsi_init_hdr(vdev, (struct virtio_scsi_cmd_req *)cmd_pi, sc);
 538
 539	if (!rq || !scsi_prot_sg_count(sc))
 540		return;
 541
 542	bi = blk_get_integrity(rq->q->disk);
 543
 544	if (sc->sc_data_direction == DMA_TO_DEVICE)
 545		cmd_pi->pi_bytesout = cpu_to_virtio32(vdev,
 546						      bio_integrity_bytes(bi,
 547							blk_rq_sectors(rq)));
 548	else if (sc->sc_data_direction == DMA_FROM_DEVICE)
 549		cmd_pi->pi_bytesin = cpu_to_virtio32(vdev,
 550						     bio_integrity_bytes(bi,
 551							blk_rq_sectors(rq)));
 552}
 553#endif
 554
 555static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi,
 556						  struct scsi_cmnd *sc)
 557{
 558	u32 tag = blk_mq_unique_tag(scsi_cmd_to_rq(sc));
 559	u16 hwq = blk_mq_unique_tag_to_hwq(tag);
 560
 561	return &vscsi->req_vqs[hwq];
 562}
 563
 564static int virtscsi_queuecommand(struct Scsi_Host *shost,
 565				 struct scsi_cmnd *sc)
 566{
 567	struct virtio_scsi *vscsi = shost_priv(shost);
 568	struct virtio_scsi_vq *req_vq = virtscsi_pick_vq_mq(vscsi, sc);
 569	struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
 570	bool kick;
 571	unsigned long flags;
 572	int req_size;
 573	int ret;
 574
 575	BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
 576
 577	/* TODO: check feature bit and fail if unsupported?  */
 578	BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
 579
 580	dev_dbg(&sc->device->sdev_gendev,
 581		"cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
 582
 583	cmd->sc = sc;
 584
 585	BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
 586
 587#ifdef CONFIG_BLK_DEV_INTEGRITY
 588	if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) {
 589		virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, sc);
 590		memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len);
 591		req_size = sizeof(cmd->req.cmd_pi);
 592	} else
 593#endif
 594	{
 595		virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, sc);
 596		memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
 597		req_size = sizeof(cmd->req.cmd);
 598	}
 599
 600	kick = (sc->flags & SCMD_LAST) != 0;
 601	ret = virtscsi_add_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd), kick);
 602	if (ret == -EIO) {
 603		cmd->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
 604		spin_lock_irqsave(&req_vq->vq_lock, flags);
 605		virtscsi_complete_cmd(vscsi, cmd);
 606		spin_unlock_irqrestore(&req_vq->vq_lock, flags);
 607	} else if (ret != 0) {
 608		return SCSI_MLQUEUE_HOST_BUSY;
 609	}
 610	return 0;
 611}
 612
 613static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
 614{
 615	DECLARE_COMPLETION_ONSTACK(comp);
 616	int ret = FAILED;
 617
 618	cmd->comp = &comp;
 619	if (virtscsi_add_cmd(&vscsi->ctrl_vq, cmd,
 620			      sizeof cmd->req.tmf, sizeof cmd->resp.tmf, true) < 0)
 621		goto out;
 622
 623	wait_for_completion(&comp);
 624	if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
 625	    cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
 626		ret = SUCCESS;
 627
 628	/*
 629	 * The spec guarantees that all requests related to the TMF have
 630	 * been completed, but the callback might not have run yet if
 631	 * we're using independent interrupts (e.g. MSI).  Poll the
 632	 * virtqueues once.
 633	 *
 634	 * In the abort case, scsi_done() will do nothing, because the
 635	 * command timed out and hence SCMD_STATE_COMPLETE has been set.
 636	 */
 637	virtscsi_poll_requests(vscsi);
 638
 639out:
 640	mempool_free(cmd, virtscsi_cmd_pool);
 641	return ret;
 642}
 643
 644static int virtscsi_device_reset(struct scsi_cmnd *sc)
 645{
 646	struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 647	struct virtio_scsi_cmd *cmd;
 648
 649	sdev_printk(KERN_INFO, sc->device, "device reset\n");
 650	cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 651	if (!cmd)
 652		return FAILED;
 653
 654	memset(cmd, 0, sizeof(*cmd));
 655	cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 656		.type = VIRTIO_SCSI_T_TMF,
 657		.subtype = cpu_to_virtio32(vscsi->vdev,
 658					     VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET),
 659		.lun[0] = 1,
 660		.lun[1] = sc->device->id,
 661		.lun[2] = (sc->device->lun >> 8) | 0x40,
 662		.lun[3] = sc->device->lun & 0xff,
 663	};
 664	return virtscsi_tmf(vscsi, cmd);
 665}
 666
 667static int virtscsi_device_alloc(struct scsi_device *sdevice)
 668{
 669	/*
 670	 * Passed through SCSI targets (e.g. with qemu's 'scsi-block')
 671	 * may have transfer limits which come from the host SCSI
 672	 * controller or something on the host side other than the
 673	 * target itself.
 674	 *
 675	 * To make this work properly, the hypervisor can adjust the
 676	 * target's VPD information to advertise these limits.  But
 677	 * for that to work, the guest has to look at the VPD pages,
 678	 * which we won't do by default if it is an SPC-2 device, even
 679	 * if it does actually support it.
 680	 *
 681	 * So, set the blist to always try to read the VPD pages.
 682	 */
 683	sdevice->sdev_bflags = BLIST_TRY_VPD_PAGES;
 684
 685	return 0;
 686}
 687
 688
 689/**
 690 * virtscsi_change_queue_depth() - Change a virtscsi target's queue depth
 691 * @sdev:	Virtscsi target whose queue depth to change
 692 * @qdepth:	New queue depth
 693 */
 694static int virtscsi_change_queue_depth(struct scsi_device *sdev, int qdepth)
 695{
 696	struct Scsi_Host *shost = sdev->host;
 697	int max_depth = shost->cmd_per_lun;
 698
 699	return scsi_change_queue_depth(sdev, min(max_depth, qdepth));
 700}
 701
 702static int virtscsi_abort(struct scsi_cmnd *sc)
 703{
 704	struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 705	struct virtio_scsi_cmd *cmd;
 706
 707	scmd_printk(KERN_INFO, sc, "abort\n");
 708	cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 709	if (!cmd)
 710		return FAILED;
 711
 712	memset(cmd, 0, sizeof(*cmd));
 713	cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 714		.type = VIRTIO_SCSI_T_TMF,
 715		.subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
 716		.lun[0] = 1,
 717		.lun[1] = sc->device->id,
 718		.lun[2] = (sc->device->lun >> 8) | 0x40,
 719		.lun[3] = sc->device->lun & 0xff,
 720		.tag = cpu_to_virtio64(vscsi->vdev, (unsigned long)sc),
 721	};
 722	return virtscsi_tmf(vscsi, cmd);
 723}
 724
 725static void virtscsi_map_queues(struct Scsi_Host *shost)
 726{
 727	struct virtio_scsi *vscsi = shost_priv(shost);
 728	int i, qoff;
 729
 730	for (i = 0, qoff = 0; i < shost->nr_maps; i++) {
 731		struct blk_mq_queue_map *map = &shost->tag_set.map[i];
 732
 733		map->nr_queues = vscsi->io_queues[i];
 734		map->queue_offset = qoff;
 735		qoff += map->nr_queues;
 736
 737		if (map->nr_queues == 0)
 738			continue;
 739
 740		/*
 741		 * Regular queues have interrupts and hence CPU affinity is
 742		 * defined by the core virtio code, but polling queues have
 743		 * no interrupts so we let the block layer assign CPU affinity.
 744		 */
 745		if (i == HCTX_TYPE_POLL)
 746			blk_mq_map_queues(map);
 747		else
 748			blk_mq_map_hw_queues(map, &vscsi->vdev->dev, 2);
 749	}
 750}
 751
 752static int virtscsi_mq_poll(struct Scsi_Host *shost, unsigned int queue_num)
 753{
 754	struct virtio_scsi *vscsi = shost_priv(shost);
 755	struct virtio_scsi_vq *virtscsi_vq = &vscsi->req_vqs[queue_num];
 756	unsigned long flags;
 757	unsigned int len;
 758	int found = 0;
 759	void *buf;
 760
 761	spin_lock_irqsave(&virtscsi_vq->vq_lock, flags);
 762
 763	while ((buf = virtqueue_get_buf(virtscsi_vq->vq, &len)) != NULL) {
 764		virtscsi_complete_cmd(vscsi, buf);
 765		found++;
 766	}
 767
 768	spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
 769
 770	return found;
 771}
 772
 773static void virtscsi_commit_rqs(struct Scsi_Host *shost, u16 hwq)
 774{
 775	struct virtio_scsi *vscsi = shost_priv(shost);
 776
 777	virtscsi_kick_vq(&vscsi->req_vqs[hwq]);
 778}
 779
 780/*
 781 * The host guarantees to respond to each command, although I/O
 782 * latencies might be higher than on bare metal.  Reset the timer
 783 * unconditionally to give the host a chance to perform EH.
 784 */
 785static enum scsi_timeout_action virtscsi_eh_timed_out(struct scsi_cmnd *scmnd)
 786{
 787	return SCSI_EH_RESET_TIMER;
 788}
 789
 790static const struct scsi_host_template virtscsi_host_template = {
 791	.module = THIS_MODULE,
 792	.name = "Virtio SCSI HBA",
 793	.proc_name = "virtio_scsi",
 794	.this_id = -1,
 795	.cmd_size = sizeof(struct virtio_scsi_cmd),
 796	.queuecommand = virtscsi_queuecommand,
 797	.mq_poll = virtscsi_mq_poll,
 798	.commit_rqs = virtscsi_commit_rqs,
 799	.change_queue_depth = virtscsi_change_queue_depth,
 800	.eh_abort_handler = virtscsi_abort,
 801	.eh_device_reset_handler = virtscsi_device_reset,
 802	.eh_timed_out = virtscsi_eh_timed_out,
 803	.sdev_init = virtscsi_device_alloc,
 804
 805	.dma_boundary = UINT_MAX,
 806	.map_queues = virtscsi_map_queues,
 807	.track_queue_depth = 1,
 808};
 809
 810#define virtscsi_config_get(vdev, fld) \
 811	({ \
 812		__virtio_native_type(struct virtio_scsi_config, fld) __val; \
 813		virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \
 814		__val; \
 815	})
 816
 817#define virtscsi_config_set(vdev, fld, val) \
 818	do { \
 819		__virtio_native_type(struct virtio_scsi_config, fld) __val = (val); \
 820		virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \
 821	} while(0)
 822
 823static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
 824			     struct virtqueue *vq)
 825{
 826	spin_lock_init(&virtscsi_vq->vq_lock);
 827	virtscsi_vq->vq = vq;
 828}
 829
 830static void virtscsi_remove_vqs(struct virtio_device *vdev)
 831{
 832	/* Stop all the virtqueues. */
 833	virtio_reset_device(vdev);
 834	vdev->config->del_vqs(vdev);
 835}
 836
 837static int virtscsi_init(struct virtio_device *vdev,
 838			 struct virtio_scsi *vscsi)
 839{
 840	int err;
 841	u32 i;
 842	u32 num_vqs, num_poll_vqs, num_req_vqs;
 843	struct virtqueue_info *vqs_info;
 844	struct virtqueue **vqs;
 845	struct irq_affinity desc = { .pre_vectors = 2 };
 846
 847	num_req_vqs = vscsi->num_queues;
 848	num_vqs = num_req_vqs + VIRTIO_SCSI_VQ_BASE;
 849	vqs = kmalloc_array(num_vqs, sizeof(struct virtqueue *), GFP_KERNEL);
 850	vqs_info = kcalloc(num_vqs, sizeof(*vqs_info), GFP_KERNEL);
 851
 852	if (!vqs || !vqs_info) {
 853		err = -ENOMEM;
 854		goto out;
 855	}
 856
 857	num_poll_vqs = min_t(unsigned int, virtscsi_poll_queues,
 858			     num_req_vqs - 1);
 859	vscsi->io_queues[HCTX_TYPE_DEFAULT] = num_req_vqs - num_poll_vqs;
 860	vscsi->io_queues[HCTX_TYPE_READ] = 0;
 861	vscsi->io_queues[HCTX_TYPE_POLL] = num_poll_vqs;
 862
 863	dev_info(&vdev->dev, "%d/%d/%d default/read/poll queues\n",
 864		 vscsi->io_queues[HCTX_TYPE_DEFAULT],
 865		 vscsi->io_queues[HCTX_TYPE_READ],
 866		 vscsi->io_queues[HCTX_TYPE_POLL]);
 867
 868	vqs_info[0].callback = virtscsi_ctrl_done;
 869	vqs_info[0].name = "control";
 870	vqs_info[1].callback = virtscsi_event_done;
 871	vqs_info[1].name = "event";
 872	for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs - num_poll_vqs; i++) {
 873		vqs_info[i].callback = virtscsi_req_done;
 874		vqs_info[i].name = "request";
 875	}
 876
 877	for (; i < num_vqs; i++)
 878		vqs_info[i].name = "request_poll";
 879
 880	/* Discover virtqueues and write information to configuration.  */
 881	err = virtio_find_vqs(vdev, num_vqs, vqs, vqs_info, &desc);
 882	if (err)
 883		goto out;
 884
 885	virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
 886	virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
 887	for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
 888		virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
 889				 vqs[i]);
 890
 891	virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
 892	virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
 893
 894	err = 0;
 895
 896out:
 897	kfree(vqs_info);
 898	kfree(vqs);
 899	if (err)
 900		virtscsi_remove_vqs(vdev);
 901	return err;
 902}
 903
 904static int virtscsi_probe(struct virtio_device *vdev)
 905{
 906	struct Scsi_Host *shost;
 907	struct virtio_scsi *vscsi;
 908	int err;
 909	u32 sg_elems, num_targets;
 910	u32 cmd_per_lun;
 911	u32 num_queues;
 912
 913	if (!vdev->config->get) {
 914		dev_err(&vdev->dev, "%s failure: config access disabled\n",
 915			__func__);
 916		return -EINVAL;
 917	}
 918
 919	/* We need to know how many queues before we allocate. */
 920	num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
 921	num_queues = min_t(unsigned int, nr_cpu_ids, num_queues);
 922	num_queues = blk_mq_num_possible_queues(num_queues);
 923
 924	num_targets = virtscsi_config_get(vdev, max_target) + 1;
 925
 926	shost = scsi_host_alloc(&virtscsi_host_template,
 927				struct_size(vscsi, req_vqs, num_queues));
 928	if (!shost)
 929		return -ENOMEM;
 930
 931	sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
 932	shost->sg_tablesize = sg_elems;
 933	shost->nr_maps = 1;
 934	vscsi = shost_priv(shost);
 935	vscsi->vdev = vdev;
 936	vscsi->num_queues = num_queues;
 937	vdev->priv = shost;
 938
 939	err = virtscsi_init(vdev, vscsi);
 940	if (err)
 941		goto virtscsi_init_failed;
 942
 943	if (vscsi->io_queues[HCTX_TYPE_POLL])
 944		shost->nr_maps = HCTX_TYPE_POLL + 1;
 945
 946	shost->can_queue = virtqueue_get_vring_size(vscsi->req_vqs[0].vq);
 947
 948	cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
 949	shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
 950	shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
 951
 952	/* LUNs > 256 are reported with format 1, so they go in the range
 953	 * 16640-32767.
 954	 */
 955	shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
 956	shost->max_id = num_targets;
 957	shost->max_channel = 0;
 958	shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
 959	shost->nr_hw_queues = num_queues;
 960
 961#ifdef CONFIG_BLK_DEV_INTEGRITY
 962	if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
 963		int host_prot;
 964
 965		host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
 966			    SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
 967			    SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
 968
 969		scsi_host_set_prot(shost, host_prot);
 970		scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC);
 971	}
 972#endif
 973
 974	err = scsi_add_host(shost, &vdev->dev);
 975	if (err)
 976		goto scsi_add_host_failed;
 977
 978	virtio_device_ready(vdev);
 979
 980	if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 981		virtscsi_kick_event_all(vscsi);
 982
 983	scsi_scan_host(shost);
 984	return 0;
 985
 986scsi_add_host_failed:
 987	vdev->config->del_vqs(vdev);
 988virtscsi_init_failed:
 989	scsi_host_put(shost);
 990	return err;
 991}
 992
 993static void virtscsi_remove(struct virtio_device *vdev)
 994{
 995	struct Scsi_Host *shost = virtio_scsi_host(vdev);
 996	struct virtio_scsi *vscsi = shost_priv(shost);
 997
 998	if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 999		virtscsi_cancel_event_work(vscsi);
1000
1001	scsi_remove_host(shost);
1002	virtscsi_remove_vqs(vdev);
1003	scsi_host_put(shost);
1004}
1005
1006#ifdef CONFIG_PM_SLEEP
1007static int virtscsi_freeze(struct virtio_device *vdev)
1008{
1009	virtscsi_remove_vqs(vdev);
1010	return 0;
1011}
1012
1013static int virtscsi_restore(struct virtio_device *vdev)
1014{
1015	struct Scsi_Host *sh = virtio_scsi_host(vdev);
1016	struct virtio_scsi *vscsi = shost_priv(sh);
1017	int err;
1018
1019	err = virtscsi_init(vdev, vscsi);
1020	if (err)
1021		return err;
1022
1023	virtio_device_ready(vdev);
1024
1025	if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
1026		virtscsi_kick_event_all(vscsi);
1027
1028	return err;
1029}
1030#endif
1031
1032static struct virtio_device_id id_table[] = {
1033	{ VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
1034	{ 0 },
1035};
1036
1037static unsigned int features[] = {
1038	VIRTIO_SCSI_F_HOTPLUG,
1039	VIRTIO_SCSI_F_CHANGE,
1040#ifdef CONFIG_BLK_DEV_INTEGRITY
1041	VIRTIO_SCSI_F_T10_PI,
1042#endif
1043};
1044
1045static struct virtio_driver virtio_scsi_driver = {
1046	.feature_table = features,
1047	.feature_table_size = ARRAY_SIZE(features),
1048	.driver.name = KBUILD_MODNAME,
1049	.id_table = id_table,
1050	.probe = virtscsi_probe,
1051#ifdef CONFIG_PM_SLEEP
1052	.freeze = virtscsi_freeze,
1053	.restore = virtscsi_restore,
1054#endif
1055	.remove = virtscsi_remove,
1056};
1057
1058static int __init virtio_scsi_init(void)
1059{
1060	int ret = -ENOMEM;
1061
1062	virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
1063	if (!virtscsi_cmd_cache) {
1064		pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
1065		goto error;
1066	}
1067
1068
1069	virtscsi_cmd_pool =
1070		mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
1071					 virtscsi_cmd_cache);
1072	if (!virtscsi_cmd_pool) {
1073		pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
1074		goto error;
1075	}
1076	ret = register_virtio_driver(&virtio_scsi_driver);
1077	if (ret < 0)
1078		goto error;
1079
1080	return 0;
1081
1082error:
1083	mempool_destroy(virtscsi_cmd_pool);
1084	virtscsi_cmd_pool = NULL;
1085	kmem_cache_destroy(virtscsi_cmd_cache);
1086	virtscsi_cmd_cache = NULL;
1087	return ret;
1088}
1089
1090static void __exit virtio_scsi_fini(void)
1091{
1092	unregister_virtio_driver(&virtio_scsi_driver);
1093	mempool_destroy(virtscsi_cmd_pool);
1094	kmem_cache_destroy(virtscsi_cmd_cache);
1095}
1096module_init(virtio_scsi_init);
1097module_exit(virtio_scsi_fini);
1098
1099MODULE_DEVICE_TABLE(virtio, id_table);
1100MODULE_DESCRIPTION("Virtio SCSI HBA driver");
1101MODULE_LICENSE("GPL");