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#include <linux/blk-mq-virtio.h>
  33
  34#include "sd.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 */
  41struct 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
  58struct virtio_scsi_event_node {
  59	struct virtio_scsi *vscsi;
  60	struct virtio_scsi_event event;
  61	struct work_struct work;
  62};
  63
  64struct virtio_scsi_vq {
  65	/* Protects vq */
  66	spinlock_t vq_lock;
  67
  68	struct virtqueue *vq;
  69};
  70
  71/* Driver instance state */
  72struct virtio_scsi {
  73	struct virtio_device *vdev;
  74
  75	/* Get some buffers ready for event vq */
  76	struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN];
  77
  78	u32 num_queues;
  79
  80	struct hlist_node node;
  81
  82	/* Protected by event_vq lock */
  83	bool stop_events;
 
 
  84
  85	struct virtio_scsi_vq ctrl_vq;
  86	struct virtio_scsi_vq event_vq;
  87	struct virtio_scsi_vq req_vqs[];
  88};
  89
  90static struct kmem_cache *virtscsi_cmd_cache;
  91static mempool_t *virtscsi_cmd_pool;
  92
  93static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
  94{
  95	return vdev->priv;
  96}
  97
  98static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
  99{
 100	if (resid)
 101		scsi_set_resid(sc, min(resid, scsi_bufflen(sc)));
 
 
 
 
 
 
 
 
 102}
 103
 104/*
 105 * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
 106 *
 107 * Called with vq_lock held.
 108 */
 109static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
 110{
 111	struct virtio_scsi_cmd *cmd = buf;
 112	struct scsi_cmnd *sc = cmd->sc;
 113	struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
 114
 115	dev_dbg(&sc->device->sdev_gendev,
 116		"cmd %p response %u status %#02x sense_len %u\n",
 117		sc, resp->response, resp->status, resp->sense_len);
 118
 119	sc->result = resp->status;
 120	virtscsi_compute_resid(sc, virtio32_to_cpu(vscsi->vdev, resp->resid));
 121	switch (resp->response) {
 122	case VIRTIO_SCSI_S_OK:
 123		set_host_byte(sc, DID_OK);
 124		break;
 125	case VIRTIO_SCSI_S_OVERRUN:
 126		set_host_byte(sc, DID_ERROR);
 127		break;
 128	case VIRTIO_SCSI_S_ABORTED:
 129		set_host_byte(sc, DID_ABORT);
 130		break;
 131	case VIRTIO_SCSI_S_BAD_TARGET:
 132		set_host_byte(sc, DID_BAD_TARGET);
 133		break;
 134	case VIRTIO_SCSI_S_RESET:
 135		set_host_byte(sc, DID_RESET);
 136		break;
 137	case VIRTIO_SCSI_S_BUSY:
 138		set_host_byte(sc, DID_BUS_BUSY);
 139		break;
 140	case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
 141		set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
 142		break;
 143	case VIRTIO_SCSI_S_TARGET_FAILURE:
 144		set_host_byte(sc, DID_BAD_TARGET);
 145		break;
 146	case VIRTIO_SCSI_S_NEXUS_FAILURE:
 147		set_status_byte(sc, SAM_STAT_RESERVATION_CONFLICT);
 148		break;
 149	default:
 150		scmd_printk(KERN_WARNING, sc, "Unknown response %d",
 151			    resp->response);
 152		fallthrough;
 153	case VIRTIO_SCSI_S_FAILURE:
 154		set_host_byte(sc, DID_ERROR);
 155		break;
 156	}
 157
 158	WARN_ON(virtio32_to_cpu(vscsi->vdev, resp->sense_len) >
 159		VIRTIO_SCSI_SENSE_SIZE);
 160	if (resp->sense_len) {
 161		memcpy(sc->sense_buffer, resp->sense,
 162		       min_t(u32,
 163			     virtio32_to_cpu(vscsi->vdev, resp->sense_len),
 164			     VIRTIO_SCSI_SENSE_SIZE));
 165	}
 166
 167	scsi_done(sc);
 
 168}
 169
 170static void virtscsi_vq_done(struct virtio_scsi *vscsi,
 171			     struct virtio_scsi_vq *virtscsi_vq,
 172			     void (*fn)(struct virtio_scsi *vscsi, void *buf))
 173{
 
 
 174	void *buf;
 175	unsigned int len;
 176	unsigned long flags;
 177	struct virtqueue *vq = virtscsi_vq->vq;
 
 
 178
 179	spin_lock_irqsave(&virtscsi_vq->vq_lock, flags);
 180	do {
 181		virtqueue_disable_cb(vq);
 182		while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
 183			fn(vscsi, buf);
 184
 185		if (unlikely(virtqueue_is_broken(vq)))
 186			break;
 187	} while (!virtqueue_enable_cb(vq));
 188	spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
 
 189}
 190
 191static void virtscsi_req_done(struct virtqueue *vq)
 192{
 193	struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 194	struct virtio_scsi *vscsi = shost_priv(sh);
 195	int index = vq->index - VIRTIO_SCSI_VQ_BASE;
 196	struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index];
 197
 198	virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd);
 199};
 200
 201static void virtscsi_poll_requests(struct virtio_scsi *vscsi)
 202{
 203	int i, num_vqs;
 204
 205	num_vqs = vscsi->num_queues;
 206	for (i = 0; i < num_vqs; i++)
 207		virtscsi_vq_done(vscsi, &vscsi->req_vqs[i],
 208				 virtscsi_complete_cmd);
 209}
 210
 211static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)
 212{
 213	struct virtio_scsi_cmd *cmd = buf;
 214
 215	if (cmd->comp)
 216		complete(cmd->comp);
 
 
 217}
 218
 219static void virtscsi_ctrl_done(struct virtqueue *vq)
 220{
 221	struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 222	struct virtio_scsi *vscsi = shost_priv(sh);
 223
 224	virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free);
 225};
 226
 227static void virtscsi_handle_event(struct work_struct *work);
 228
 229static int virtscsi_kick_event(struct virtio_scsi *vscsi,
 230			       struct virtio_scsi_event_node *event_node)
 231{
 232	int err;
 233	struct scatterlist sg;
 234	unsigned long flags;
 235
 236	INIT_WORK(&event_node->work, virtscsi_handle_event);
 237	sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
 238
 239	spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
 240
 241	err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node,
 242				  GFP_ATOMIC);
 243	if (!err)
 244		virtqueue_kick(vscsi->event_vq.vq);
 245
 246	spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
 247
 248	return err;
 249}
 250
 251static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
 252{
 253	int i;
 254
 255	for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
 256		vscsi->event_list[i].vscsi = vscsi;
 257		virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
 258	}
 259
 260	return 0;
 261}
 262
 263static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
 
 264{
 
 
 
 265	int i;
 266
 267	/* Stop scheduling work before calling cancel_work_sync.  */
 268	spin_lock_irq(&vscsi->event_vq.vq_lock);
 269	vscsi->stop_events = true;
 270	spin_unlock_irq(&vscsi->event_vq.vq_lock);
 271
 272	for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
 273		cancel_work_sync(&vscsi->event_list[i].work);
 274}
 275
 276static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
 277					    struct virtio_scsi_event *event)
 278{
 279	struct scsi_device *sdev;
 280	struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 281	unsigned int target = event->lun[1];
 282	unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 283
 284	switch (virtio32_to_cpu(vscsi->vdev, event->reason)) {
 285	case VIRTIO_SCSI_EVT_RESET_RESCAN:
 286		if (lun == 0) {
 287			scsi_scan_target(&shost->shost_gendev, 0, target,
 288					 SCAN_WILD_CARD, SCSI_SCAN_INITIAL);
 289		} else {
 290			scsi_add_device(shost, 0, target, lun);
 291		}
 292		break;
 293	case VIRTIO_SCSI_EVT_RESET_REMOVED:
 294		sdev = scsi_device_lookup(shost, 0, target, lun);
 295		if (sdev) {
 296			scsi_remove_device(sdev);
 297			scsi_device_put(sdev);
 298		} else {
 299			pr_err("SCSI device %d 0 %d %d not found\n",
 300				shost->host_no, target, lun);
 301		}
 302		break;
 303	default:
 304		pr_info("Unsupported virtio scsi event reason %x\n", event->reason);
 305	}
 306}
 307
 308static void virtscsi_handle_param_change(struct virtio_scsi *vscsi,
 309					 struct virtio_scsi_event *event)
 310{
 311	struct scsi_device *sdev;
 312	struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 313	unsigned int target = event->lun[1];
 314	unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 315	u8 asc = virtio32_to_cpu(vscsi->vdev, event->reason) & 255;
 316	u8 ascq = virtio32_to_cpu(vscsi->vdev, event->reason) >> 8;
 317
 318	sdev = scsi_device_lookup(shost, 0, target, lun);
 319	if (!sdev) {
 320		pr_err("SCSI device %d 0 %d %d not found\n",
 321			shost->host_no, target, lun);
 322		return;
 323	}
 324
 325	/* Handle "Parameters changed", "Mode parameters changed", and
 326	   "Capacity data has changed".  */
 327	if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
 328		scsi_rescan_device(&sdev->sdev_gendev);
 329
 330	scsi_device_put(sdev);
 331}
 332
 333static void virtscsi_rescan_hotunplug(struct virtio_scsi *vscsi)
 334{
 335	struct scsi_device *sdev;
 336	struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 337	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
 338	int result, inquiry_len, inq_result_len = 256;
 339	char *inq_result = kmalloc(inq_result_len, GFP_KERNEL);
 340
 341	shost_for_each_device(sdev, shost) {
 342		inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
 343
 344		memset(scsi_cmd, 0, sizeof(scsi_cmd));
 345		scsi_cmd[0] = INQUIRY;
 346		scsi_cmd[4] = (unsigned char) inquiry_len;
 347
 348		memset(inq_result, 0, inq_result_len);
 349
 350		result = scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE,
 351					  inq_result, inquiry_len, NULL,
 352					  SD_TIMEOUT, SD_MAX_RETRIES, NULL);
 353
 354		if (result == 0 && inq_result[0] >> 5) {
 355			/* PQ indicates the LUN is not attached */
 356			scsi_remove_device(sdev);
 357		} else if (result > 0 && host_byte(result) == DID_BAD_TARGET) {
 358			/*
 359			 * If all LUNs of a virtio-scsi device are unplugged
 360			 * it will respond with BAD TARGET on any INQUIRY
 361			 * command.
 362			 * Remove the device in this case as well.
 363			 */
 364			scsi_remove_device(sdev);
 365		}
 366	}
 367
 368	kfree(inq_result);
 369}
 370
 371static void virtscsi_handle_event(struct work_struct *work)
 372{
 373	struct virtio_scsi_event_node *event_node =
 374		container_of(work, struct virtio_scsi_event_node, work);
 375	struct virtio_scsi *vscsi = event_node->vscsi;
 376	struct virtio_scsi_event *event = &event_node->event;
 377
 378	if (event->event &
 379	    cpu_to_virtio32(vscsi->vdev, VIRTIO_SCSI_T_EVENTS_MISSED)) {
 380		event->event &= ~cpu_to_virtio32(vscsi->vdev,
 381						   VIRTIO_SCSI_T_EVENTS_MISSED);
 382		virtscsi_rescan_hotunplug(vscsi);
 383		scsi_scan_host(virtio_scsi_host(vscsi->vdev));
 384	}
 385
 386	switch (virtio32_to_cpu(vscsi->vdev, event->event)) {
 387	case VIRTIO_SCSI_T_NO_EVENT:
 388		break;
 389	case VIRTIO_SCSI_T_TRANSPORT_RESET:
 390		virtscsi_handle_transport_reset(vscsi, event);
 391		break;
 392	case VIRTIO_SCSI_T_PARAM_CHANGE:
 393		virtscsi_handle_param_change(vscsi, event);
 394		break;
 395	default:
 396		pr_err("Unsupported virtio scsi event %x\n", event->event);
 397	}
 398	virtscsi_kick_event(vscsi, event_node);
 399}
 400
 401static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf)
 402{
 403	struct virtio_scsi_event_node *event_node = buf;
 404
 405	if (!vscsi->stop_events)
 406		queue_work(system_freezable_wq, &event_node->work);
 407}
 408
 409static void virtscsi_event_done(struct virtqueue *vq)
 410{
 411	struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 412	struct virtio_scsi *vscsi = shost_priv(sh);
 
 413
 414	virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event);
 415};
 
 416
 417static int __virtscsi_add_cmd(struct virtqueue *vq,
 418			    struct virtio_scsi_cmd *cmd,
 419			    size_t req_size, size_t resp_size)
 420{
 421	struct scsi_cmnd *sc = cmd->sc;
 422	struct scatterlist *sgs[6], req, resp;
 423	struct sg_table *out, *in;
 424	unsigned out_num = 0, in_num = 0;
 425
 426	out = in = NULL;
 427
 428	if (sc && sc->sc_data_direction != DMA_NONE) {
 429		if (sc->sc_data_direction != DMA_FROM_DEVICE)
 430			out = &sc->sdb.table;
 431		if (sc->sc_data_direction != DMA_TO_DEVICE)
 432			in = &sc->sdb.table;
 433	}
 434
 435	/* Request header.  */
 436	sg_init_one(&req, &cmd->req, req_size);
 437	sgs[out_num++] = &req;
 438
 439	/* Data-out buffer.  */
 440	if (out) {
 441		/* Place WRITE protection SGLs before Data OUT payload */
 442		if (scsi_prot_sg_count(sc))
 443			sgs[out_num++] = scsi_prot_sglist(sc);
 444		sgs[out_num++] = out->sgl;
 445	}
 446
 447	/* Response header.  */
 448	sg_init_one(&resp, &cmd->resp, resp_size);
 449	sgs[out_num + in_num++] = &resp;
 450
 451	/* Data-in buffer */
 452	if (in) {
 453		/* Place READ protection SGLs before Data IN payload */
 454		if (scsi_prot_sg_count(sc))
 455			sgs[out_num + in_num++] = scsi_prot_sglist(sc);
 456		sgs[out_num + in_num++] = in->sgl;
 457	}
 458
 459	return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC);
 460}
 461
 462static void virtscsi_kick_vq(struct virtio_scsi_vq *vq)
 463{
 464	bool needs_kick;
 465	unsigned long flags;
 466
 467	spin_lock_irqsave(&vq->vq_lock, flags);
 468	needs_kick = virtqueue_kick_prepare(vq->vq);
 469	spin_unlock_irqrestore(&vq->vq_lock, flags);
 470
 471	if (needs_kick)
 472		virtqueue_notify(vq->vq);
 473}
 474
 475/**
 476 * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue, optionally kick it
 477 * @vq		: the struct virtqueue we're talking about
 478 * @cmd		: command structure
 479 * @req_size	: size of the request buffer
 480 * @resp_size	: size of the response buffer
 481 * @kick	: whether to kick the virtqueue immediately
 482 */
 483static int virtscsi_add_cmd(struct virtio_scsi_vq *vq,
 484			     struct virtio_scsi_cmd *cmd,
 485			     size_t req_size, size_t resp_size,
 486			     bool kick)
 487{
 
 488	unsigned long flags;
 489	int err;
 490	bool needs_kick = false;
 491
 492	spin_lock_irqsave(&vq->vq_lock, flags);
 493	err = __virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size);
 494	if (!err && kick)
 495		needs_kick = virtqueue_kick_prepare(vq->vq);
 496
 497	spin_unlock_irqrestore(&vq->vq_lock, flags);
 498
 499	if (needs_kick)
 500		virtqueue_notify(vq->vq);
 501	return err;
 502}
 503
 504static void virtio_scsi_init_hdr(struct virtio_device *vdev,
 505				 struct virtio_scsi_cmd_req *cmd,
 506				 struct scsi_cmnd *sc)
 507{
 508	cmd->lun[0] = 1;
 509	cmd->lun[1] = sc->device->id;
 510	cmd->lun[2] = (sc->device->lun >> 8) | 0x40;
 511	cmd->lun[3] = sc->device->lun & 0xff;
 512	cmd->tag = cpu_to_virtio64(vdev, (unsigned long)sc);
 513	cmd->task_attr = VIRTIO_SCSI_S_SIMPLE;
 514	cmd->prio = 0;
 515	cmd->crn = 0;
 516}
 517
 518#ifdef CONFIG_BLK_DEV_INTEGRITY
 519static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev,
 520				    struct virtio_scsi_cmd_req_pi *cmd_pi,
 521				    struct scsi_cmnd *sc)
 522{
 523	struct request *rq = scsi_cmd_to_rq(sc);
 524	struct blk_integrity *bi;
 525
 526	virtio_scsi_init_hdr(vdev, (struct virtio_scsi_cmd_req *)cmd_pi, sc);
 527
 528	if (!rq || !scsi_prot_sg_count(sc))
 529		return;
 530
 531	bi = blk_get_integrity(rq->q->disk);
 532
 533	if (sc->sc_data_direction == DMA_TO_DEVICE)
 534		cmd_pi->pi_bytesout = cpu_to_virtio32(vdev,
 535						      bio_integrity_bytes(bi,
 536							blk_rq_sectors(rq)));
 537	else if (sc->sc_data_direction == DMA_FROM_DEVICE)
 538		cmd_pi->pi_bytesin = cpu_to_virtio32(vdev,
 539						     bio_integrity_bytes(bi,
 540							blk_rq_sectors(rq)));
 541}
 542#endif
 543
 544static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi,
 545						  struct scsi_cmnd *sc)
 546{
 547	u32 tag = blk_mq_unique_tag(scsi_cmd_to_rq(sc));
 548	u16 hwq = blk_mq_unique_tag_to_hwq(tag);
 549
 550	return &vscsi->req_vqs[hwq];
 551}
 552
 553static int virtscsi_queuecommand(struct Scsi_Host *shost,
 554				 struct scsi_cmnd *sc)
 555{
 556	struct virtio_scsi *vscsi = shost_priv(shost);
 557	struct virtio_scsi_vq *req_vq = virtscsi_pick_vq_mq(vscsi, sc);
 558	struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
 559	bool kick;
 560	unsigned long flags;
 561	int req_size;
 562	int ret;
 563
 564	BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
 565
 566	/* TODO: check feature bit and fail if unsupported?  */
 567	BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
 568
 569	dev_dbg(&sc->device->sdev_gendev,
 570		"cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
 571
 
 
 
 
 
 
 572	cmd->sc = sc;
 
 
 
 
 
 
 
 
 
 
 573
 574	BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
 
 575
 576#ifdef CONFIG_BLK_DEV_INTEGRITY
 577	if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) {
 578		virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, sc);
 579		memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len);
 580		req_size = sizeof(cmd->req.cmd_pi);
 581	} else
 582#endif
 583	{
 584		virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, sc);
 585		memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
 586		req_size = sizeof(cmd->req.cmd);
 587	}
 588
 589	kick = (sc->flags & SCMD_LAST) != 0;
 590	ret = virtscsi_add_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd), kick);
 591	if (ret == -EIO) {
 592		cmd->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
 593		spin_lock_irqsave(&req_vq->vq_lock, flags);
 594		virtscsi_complete_cmd(vscsi, cmd);
 595		spin_unlock_irqrestore(&req_vq->vq_lock, flags);
 596	} else if (ret != 0) {
 597		return SCSI_MLQUEUE_HOST_BUSY;
 598	}
 599	return 0;
 600}
 601
 602static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
 603{
 604	DECLARE_COMPLETION_ONSTACK(comp);
 605	int ret = FAILED;
 606
 607	cmd->comp = &comp;
 608	if (virtscsi_add_cmd(&vscsi->ctrl_vq, cmd,
 609			      sizeof cmd->req.tmf, sizeof cmd->resp.tmf, true) < 0)
 
 610		goto out;
 611
 612	wait_for_completion(&comp);
 613	if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
 614	    cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
 615		ret = SUCCESS;
 616
 617	/*
 618	 * The spec guarantees that all requests related to the TMF have
 619	 * been completed, but the callback might not have run yet if
 620	 * we're using independent interrupts (e.g. MSI).  Poll the
 621	 * virtqueues once.
 622	 *
 623	 * In the abort case, scsi_done() will do nothing, because the
 624	 * command timed out and hence SCMD_STATE_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 void 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	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 scsi_timeout_action virtscsi_eh_timed_out(struct scsi_cmnd *scmnd)
 735{
 736	return SCSI_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	virtio_reset_device(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 virtio_scsi_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 virtio_scsi_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(virtio_scsi_init);
1030module_exit(virtio_scsi_fini);
1031
1032MODULE_DEVICE_TABLE(virtio, id_table);
1033MODULE_DESCRIPTION("Virtio SCSI HBA driver");
1034MODULE_LICENSE("GPL");