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