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/*

 * Virtio SCSI HBA

 *

 * Copyright IBM, Corp. 2010

 * Copyright Red Hat, Inc. 2011

 *

 * Authors:

 *   Stefan Hajnoczi    <stefanha@linux.vnet.ibm.com>

 *   Paolo Bonzini      <pbonzini@redhat.com>

 *

 * This work is licensed under the terms of the GNU GPL, version 2 or later.

 * See the COPYING file in the top-level directory.

 *

 */

#include "virtio-scsi.h"

#include <hw/scsi.h>

#include <hw/scsi-defs.h>

#define VIRTIO_SCSI_VQ_SIZE     128

#define VIRTIO_SCSI_CDB_SIZE    32

#define VIRTIO_SCSI_SENSE_SIZE  96

#define VIRTIO_SCSI_MAX_CHANNEL 0

#define VIRTIO_SCSI_MAX_TARGET  255

#define VIRTIO_SCSI_MAX_LUN     16383

/* Response codes */

#define VIRTIO_SCSI_S_OK                       0

#define VIRTIO_SCSI_S_OVERRUN                  1

#define VIRTIO_SCSI_S_ABORTED                  2

#define VIRTIO_SCSI_S_BAD_TARGET               3

#define VIRTIO_SCSI_S_RESET                    4

#define VIRTIO_SCSI_S_BUSY                     5

#define VIRTIO_SCSI_S_TRANSPORT_FAILURE        6

#define VIRTIO_SCSI_S_TARGET_FAILURE           7

#define VIRTIO_SCSI_S_NEXUS_FAILURE            8

#define VIRTIO_SCSI_S_FAILURE                  9

#define VIRTIO_SCSI_S_FUNCTION_SUCCEEDED       10

#define VIRTIO_SCSI_S_FUNCTION_REJECTED        11

#define VIRTIO_SCSI_S_INCORRECT_LUN            12

/* Controlq type codes.  */

#define VIRTIO_SCSI_T_TMF                      0

#define VIRTIO_SCSI_T_AN_QUERY                 1

#define VIRTIO_SCSI_T_AN_SUBSCRIBE             2

/* Valid TMF subtypes.  */

#define VIRTIO_SCSI_T_TMF_ABORT_TASK           0

#define VIRTIO_SCSI_T_TMF_ABORT_TASK_SET       1

#define VIRTIO_SCSI_T_TMF_CLEAR_ACA            2

#define VIRTIO_SCSI_T_TMF_CLEAR_TASK_SET       3

#define VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET      4

#define VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET   5

#define VIRTIO_SCSI_T_TMF_QUERY_TASK           6

#define VIRTIO_SCSI_T_TMF_QUERY_TASK_SET       7

/* Events.  */

#define VIRTIO_SCSI_T_EVENTS_MISSED            0x80000000

#define VIRTIO_SCSI_T_NO_EVENT                 0

#define VIRTIO_SCSI_T_TRANSPORT_RESET          1

#define VIRTIO_SCSI_T_ASYNC_NOTIFY             2

/* SCSI command request, followed by data-out */

typedef struct {

    uint8_t lun[8];              /* Logical Unit Number */

    uint64_t tag;                /* Command identifier */

    uint8_t task_attr;           /* Task attribute */

    uint8_t prio;

    uint8_t crn;

    uint8_t cdb[];

} QEMU_PACKED VirtIOSCSICmdReq;

/* Response, followed by sense data and data-in */

typedef struct {

    uint32_t sense_len;          /* Sense data length */

    uint32_t resid;              /* Residual bytes in data buffer */

    uint16_t status_qualifier;   /* Status qualifier */

    uint8_t status;              /* Command completion status */

    uint8_t response;            /* Response values */

    uint8_t sense[];

} QEMU_PACKED VirtIOSCSICmdResp;

/* Task Management Request */

typedef struct {

    uint32_t type;

    uint32_t subtype;

    uint8_t lun[8];

    uint64_t tag;

} QEMU_PACKED VirtIOSCSICtrlTMFReq;

typedef struct {

    uint8_t response;

} QEMU_PACKED VirtIOSCSICtrlTMFResp;

/* Asynchronous notification query/subscription */

typedef struct {

    uint32_t type;

    uint8_t lun[8];

    uint32_t event_requested;

} QEMU_PACKED VirtIOSCSICtrlANReq;

typedef struct {

    uint32_t event_actual;

    uint8_t response;

} QEMU_PACKED VirtIOSCSICtrlANResp;

typedef struct {

    uint32_t event;

    uint8_t lun[8];

    uint32_t reason;

} QEMU_PACKED VirtIOSCSIEvent;

typedef struct {

    uint32_t num_queues;

    uint32_t seg_max;

    uint32_t max_sectors;

    uint32_t cmd_per_lun;

    uint32_t event_info_size;

    uint32_t sense_size;

    uint32_t cdb_size;

    uint16_t max_channel;

    uint16_t max_target;

    uint32_t max_lun;

} QEMU_PACKED VirtIOSCSIConfig;

typedef struct {

    VirtIODevice vdev;

    DeviceState *qdev;

    VirtIOSCSIConf *conf;

    SCSIBus bus;

    uint32_t sense_size;

    uint32_t cdb_size;

    int resetting;

    VirtQueue *ctrl_vq;

    VirtQueue *event_vq;

    VirtQueue *cmd_vqs[0];

} VirtIOSCSI;

typedef struct VirtIOSCSIReq {

    VirtIOSCSI *dev;

    VirtQueue *vq;

    VirtQueueElement elem;

    QEMUSGList qsgl;

    SCSIRequest *sreq;

    union {

        char                  *buf;

        VirtIOSCSICmdReq      *cmd;

        VirtIOSCSICtrlTMFReq  *tmf;

        VirtIOSCSICtrlANReq   *an;

    } req;

    union {

        char                  *buf;

        VirtIOSCSICmdResp     *cmd;

        VirtIOSCSICtrlTMFResp *tmf;

        VirtIOSCSICtrlANResp  *an;

        VirtIOSCSIEvent       *event;

    } resp;

} VirtIOSCSIReq;

static inline int virtio_scsi_get_lun(uint8_t *lun)

{

    return ((lun[2] << 8) | lun[3]) & 0x3FFF;

}

static inline SCSIDevice *virtio_scsi_device_find(VirtIOSCSI *s, uint8_t *lun)

{

    if (lun[0] != 1) {

        return NULL;

    }

    if (lun[2] != 0 && !(lun[2] >= 0x40 && lun[2] < 0x80)) {

        return NULL;

    }

    return scsi_device_find(&s->bus, 0, lun[1], virtio_scsi_get_lun(lun));

}

static void virtio_scsi_complete_req(VirtIOSCSIReq *req)

{

    VirtIOSCSI *s = req->dev;

    VirtQueue *vq = req->vq;

    virtqueue_push(vq, &req->elem, req->qsgl.size + req->elem.in_sg[0].iov_len);

    qemu_sglist_destroy(&req->qsgl);

    if (req->sreq) {

        req->sreq->hba_private = NULL;

        scsi_req_unref(req->sreq);

    }

    g_free(req);

    virtio_notify(&s->vdev, vq);

}

static void virtio_scsi_bad_req(void)

{

    error_report("wrong size for virtio-scsi headers");

    exit(1);

}

static void qemu_sgl_init_external(QEMUSGList *qsgl, struct iovec *sg,

                                   target_phys_addr_t *addr, int num)

{

    memset(qsgl, 0, sizeof(*qsgl));

    while (num--) {

        qemu_sglist_add(qsgl, *(addr++), (sg++)->iov_len);

    }

}

static void virtio_scsi_parse_req(VirtIOSCSI *s, VirtQueue *vq,

                                  VirtIOSCSIReq *req)

{

    assert(req->elem.out_num && req->elem.in_num);

    req->vq = vq;

    req->dev = s;

    req->sreq = NULL;

    req->req.buf = req->elem.out_sg[0].iov_base;

    req->resp.buf = req->elem.in_sg[0].iov_base;

    if (req->elem.out_num > 1) {

        qemu_sgl_init_external(&req->qsgl, &req->elem.out_sg[1],

                               &req->elem.out_addr[1],

                               req->elem.out_num - 1);

    } else {

        qemu_sgl_init_external(&req->qsgl, &req->elem.in_sg[1],

                               &req->elem.in_addr[1],

                               req->elem.in_num - 1);

    }

}

static VirtIOSCSIReq *virtio_scsi_pop_req(VirtIOSCSI *s, VirtQueue *vq)

{

    VirtIOSCSIReq *req;

    req = g_malloc(sizeof(*req));

    if (!virtqueue_pop(vq, &req->elem)) {

        g_free(req);

        return NULL;

    }

    virtio_scsi_parse_req(s, vq, req);

    return req;

}

static void virtio_scsi_save_request(QEMUFile *f, SCSIRequest *sreq)

{

    VirtIOSCSIReq *req = sreq->hba_private;

    uint32_t n = virtio_queue_get_id(req->vq) - 2;

    assert(n < req->dev->conf->num_queues);

    qemu_put_be32s(f, &n);

    qemu_put_buffer(f, (unsigned char *)&req->elem, sizeof(req->elem));

}

static void *virtio_scsi_load_request(QEMUFile *f, SCSIRequest *sreq)

{

    SCSIBus *bus = sreq->bus;

    VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);

    VirtIOSCSIReq *req;

    uint32_t n;

    req = g_malloc(sizeof(*req));

    qemu_get_be32s(f, &n);

    assert(n < s->conf->num_queues);

    qemu_get_buffer(f, (unsigned char *)&req->elem, sizeof(req->elem));

    virtio_scsi_parse_req(s, s->cmd_vqs[n], req);

    scsi_req_ref(sreq);

    req->sreq = sreq;

    if (req->sreq->cmd.mode != SCSI_XFER_NONE) {

        int req_mode =

            (req->elem.in_num > 1 ? SCSI_XFER_FROM_DEV : SCSI_XFER_TO_DEV);

        assert(req->sreq->cmd.mode == req_mode);

    }

    return req;

}

static void virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req)

{

    SCSIDevice *d = virtio_scsi_device_find(s, req->req.tmf->lun);

    SCSIRequest *r, *next;

    BusChild *kid;

    int target;

    /* Here VIRTIO_SCSI_S_OK means "FUNCTION COMPLETE".  */

    req->resp.tmf->response = VIRTIO_SCSI_S_OK;

    switch (req->req.tmf->subtype) {

    case VIRTIO_SCSI_T_TMF_ABORT_TASK:

    case VIRTIO_SCSI_T_TMF_QUERY_TASK:

        if (!d) {

            goto fail;

        }

        if (d->lun != virtio_scsi_get_lun(req->req.tmf->lun)) {

            goto incorrect_lun;

        }

        QTAILQ_FOREACH_SAFE(r, &d->requests, next, next) {

            if (r->tag == req->req.tmf->tag) {

                break;

            }

        }

        if (r && r->hba_private) {

            if (req->req.tmf->subtype == VIRTIO_SCSI_T_TMF_QUERY_TASK) {

                /* "If the specified command is present in the task set, then

                 * return a service response set to FUNCTION SUCCEEDED".

                 */

                req->resp.tmf->response = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;

            } else {

                scsi_req_cancel(r);

            }

        }

        break;

    case VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET:

        if (!d) {

            goto fail;

        }

        if (d->lun != virtio_scsi_get_lun(req->req.tmf->lun)) {

            goto incorrect_lun;

        }

        s->resetting++;

        qdev_reset_all(&d->qdev);

        s->resetting--;

        break;

    case VIRTIO_SCSI_T_TMF_ABORT_TASK_SET:

    case VIRTIO_SCSI_T_TMF_CLEAR_TASK_SET:

    case VIRTIO_SCSI_T_TMF_QUERY_TASK_SET:

        if (!d) {

            goto fail;

        }

        if (d->lun != virtio_scsi_get_lun(req->req.tmf->lun)) {

            goto incorrect_lun;

        }

        QTAILQ_FOREACH_SAFE(r, &d->requests, next, next) {

            if (r->hba_private) {

                if (req->req.tmf->subtype == VIRTIO_SCSI_T_TMF_QUERY_TASK_SET) {

                    /* "If there is any command present in the task set, then

                     * return a service response set to FUNCTION SUCCEEDED".

                     */

                    req->resp.tmf->response = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;

                    break;

                } else {

                    scsi_req_cancel(r);

                }

            }

        }

        break;

    case VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET:

        target = req->req.tmf->lun[1];

        s->resetting++;

        QTAILQ_FOREACH(kid, &s->bus.qbus.children, sibling) {

             d = DO_UPCAST(SCSIDevice, qdev, kid->child);

             if (d->channel == 0 && d->id == target) {

                qdev_reset_all(&d->qdev);

             }

        }

        s->resetting--;

        break;

    case VIRTIO_SCSI_T_TMF_CLEAR_ACA:

    default:

        req->resp.tmf->response = VIRTIO_SCSI_S_FUNCTION_REJECTED;

        break;

    }

    return;

incorrect_lun:

    req->resp.tmf->response = VIRTIO_SCSI_S_INCORRECT_LUN;

    return;

fail:

    req->resp.tmf->response = VIRTIO_SCSI_S_BAD_TARGET;

}

static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)

{

    VirtIOSCSI *s = (VirtIOSCSI *)vdev;

    VirtIOSCSIReq *req;

    while ((req = virtio_scsi_pop_req(s, vq))) {

        int out_size, in_size;

        if (req->elem.out_num < 1 || req->elem.in_num < 1) {

            virtio_scsi_bad_req();

            continue;

        }

        out_size = req->elem.out_sg[0].iov_len;

        in_size = req->elem.in_sg[0].iov_len;

        if (req->req.tmf->type == VIRTIO_SCSI_T_TMF) {

            if (out_size < sizeof(VirtIOSCSICtrlTMFReq) ||

                in_size < sizeof(VirtIOSCSICtrlTMFResp)) {

                virtio_scsi_bad_req();

            }

            virtio_scsi_do_tmf(s, req);

        } else if (req->req.tmf->type == VIRTIO_SCSI_T_AN_QUERY ||

                   req->req.tmf->type == VIRTIO_SCSI_T_AN_SUBSCRIBE) {

            if (out_size < sizeof(VirtIOSCSICtrlANReq) ||

                in_size < sizeof(VirtIOSCSICtrlANResp)) {

                virtio_scsi_bad_req();

            }

            req->resp.an->event_actual = 0;

            req->resp.an->response = VIRTIO_SCSI_S_OK;

        }

        virtio_scsi_complete_req(req);

    }

}

static void virtio_scsi_handle_event(VirtIODevice *vdev, VirtQueue *vq)

{

}

static void virtio_scsi_command_complete(SCSIRequest *r, uint32_t status,

                                         size_t resid)

{

    VirtIOSCSIReq *req = r->hba_private;

    req->resp.cmd->response = VIRTIO_SCSI_S_OK;

    req->resp.cmd->status = status;

    if (req->resp.cmd->status == GOOD) {

        req->resp.cmd->resid = resid;

    } else {

        req->resp.cmd->resid = 0;

        req->resp.cmd->sense_len =

            scsi_req_get_sense(r, req->resp.cmd->sense, VIRTIO_SCSI_SENSE_SIZE);

    }

    virtio_scsi_complete_req(req);

}

static QEMUSGList *virtio_scsi_get_sg_list(SCSIRequest *r)

{

    VirtIOSCSIReq *req = r->hba_private;

    return &req->qsgl;

}

static void virtio_scsi_request_cancelled(SCSIRequest *r)

{

    VirtIOSCSIReq *req = r->hba_private;

    if (!req) {

        return;

    }

    if (req->dev->resetting) {

        req->resp.cmd->response = VIRTIO_SCSI_S_RESET;

    } else {

        req->resp.cmd->response = VIRTIO_SCSI_S_ABORTED;

    }

    virtio_scsi_complete_req(req);

}

static void virtio_scsi_fail_cmd_req(VirtIOSCSIReq *req)

{

    req->resp.cmd->response = VIRTIO_SCSI_S_FAILURE;

    virtio_scsi_complete_req(req);

}

static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)

{

    VirtIOSCSI *s = (VirtIOSCSI *)vdev;

    VirtIOSCSIReq *req;

    int n;

    while ((req = virtio_scsi_pop_req(s, vq))) {

        SCSIDevice *d;

        int out_size, in_size;

        if (req->elem.out_num < 1 || req->elem.in_num < 1) {

            virtio_scsi_bad_req();

        }

        out_size = req->elem.out_sg[0].iov_len;

        in_size = req->elem.in_sg[0].iov_len;

        if (out_size < sizeof(VirtIOSCSICmdReq) + s->cdb_size ||

            in_size < sizeof(VirtIOSCSICmdResp) + s->sense_size) {

            virtio_scsi_bad_req();

        }

        if (req->elem.out_num > 1 && req->elem.in_num > 1) {

            virtio_scsi_fail_cmd_req(req);

            continue;

        }

        d = virtio_scsi_device_find(s, req->req.cmd->lun);

        if (!d) {

            req->resp.cmd->response = VIRTIO_SCSI_S_BAD_TARGET;

            virtio_scsi_complete_req(req);

            continue;

        }

        req->sreq = scsi_req_new(d, req->req.cmd->tag,

                                 virtio_scsi_get_lun(req->req.cmd->lun),

                                 req->req.cmd->cdb, req);

        if (req->sreq->cmd.mode != SCSI_XFER_NONE) {

            int req_mode =

                (req->elem.in_num > 1 ? SCSI_XFER_FROM_DEV : SCSI_XFER_TO_DEV);

            if (req->sreq->cmd.mode != req_mode ||

                req->sreq->cmd.xfer > req->qsgl.size) {

                req->resp.cmd->response = VIRTIO_SCSI_S_OVERRUN;

                virtio_scsi_complete_req(req);

                continue;

            }

        }

        n = scsi_req_enqueue(req->sreq);

        if (n) {

            scsi_req_continue(req->sreq);

        }

    }

}

static void virtio_scsi_get_config(VirtIODevice *vdev,

                                   uint8_t *config)

{

    VirtIOSCSIConfig *scsiconf = (VirtIOSCSIConfig *)config;

    VirtIOSCSI *s = (VirtIOSCSI *)vdev;

    stl_raw(&scsiconf->num_queues, s->conf->num_queues);

    stl_raw(&scsiconf->seg_max, 128 - 2);

    stl_raw(&scsiconf->max_sectors, s->conf->max_sectors);

    stl_raw(&scsiconf->cmd_per_lun, s->conf->cmd_per_lun);

    stl_raw(&scsiconf->event_info_size, sizeof(VirtIOSCSIEvent));

    stl_raw(&scsiconf->sense_size, s->sense_size);

    stl_raw(&scsiconf->cdb_size, s->cdb_size);

    stl_raw(&scsiconf->max_channel, VIRTIO_SCSI_MAX_CHANNEL);

    stl_raw(&scsiconf->max_target, VIRTIO_SCSI_MAX_TARGET);

    stl_raw(&scsiconf->max_lun, VIRTIO_SCSI_MAX_LUN);

}

static void virtio_scsi_set_config(VirtIODevice *vdev,

                                   const uint8_t *config)

{

    VirtIOSCSIConfig *scsiconf = (VirtIOSCSIConfig *)config;

    VirtIOSCSI *s = (VirtIOSCSI *)vdev;

    if ((uint32_t) ldl_raw(&scsiconf->sense_size) >= 65536 ||

        (uint32_t) ldl_raw(&scsiconf->cdb_size) >= 256) {

        error_report("bad data written to virtio-scsi configuration space");

        exit(1);

    }

    s->sense_size = ldl_raw(&scsiconf->sense_size);

    s->cdb_size = ldl_raw(&scsiconf->cdb_size);

}

static uint32_t virtio_scsi_get_features(VirtIODevice *vdev,

                                         uint32_t requested_features)

{

    return requested_features;

}

static void virtio_scsi_reset(VirtIODevice *vdev)

{

    VirtIOSCSI *s = (VirtIOSCSI *)vdev;

    s->sense_size = VIRTIO_SCSI_SENSE_SIZE;

    s->cdb_size = VIRTIO_SCSI_CDB_SIZE;

}

/* The device does not have anything to save beyond the virtio data.

 * Request data is saved with callbacks from SCSI devices.

 */

static void virtio_scsi_save(QEMUFile *f, void *opaque)

{

    VirtIOSCSI *s = opaque;

    virtio_save(&s->vdev, f);

}

static int virtio_scsi_load(QEMUFile *f, void *opaque, int version_id)

{

    VirtIOSCSI *s = opaque;

    int ret;

    ret = virtio_load(&s->vdev, f);

    if (ret) {

        return ret;

    }

    return 0;

}

static struct SCSIBusInfo virtio_scsi_scsi_info = {

    .tcq = true,

    .max_channel = VIRTIO_SCSI_MAX_CHANNEL,

    .max_target = VIRTIO_SCSI_MAX_TARGET,

    .max_lun = VIRTIO_SCSI_MAX_LUN,

    .complete = virtio_scsi_command_complete,

    .cancel = virtio_scsi_request_cancelled,

    .get_sg_list = virtio_scsi_get_sg_list,

    .save_request = virtio_scsi_save_request,

    .load_request = virtio_scsi_load_request,

};

VirtIODevice *virtio_scsi_init(DeviceState *dev, VirtIOSCSIConf *proxyconf)

{

    VirtIOSCSI *s;

    static int virtio_scsi_id;

    size_t sz;

    int i;

    sz = sizeof(VirtIOSCSI) + proxyconf->num_queues * sizeof(VirtQueue *);

    s = (VirtIOSCSI *)virtio_common_init("virtio-scsi", VIRTIO_ID_SCSI,

                                         sizeof(VirtIOSCSIConfig), sz);

    s->qdev = dev;

    s->conf = proxyconf;

    /* TODO set up vdev function pointers */

    s->vdev.get_config = virtio_scsi_get_config;

    s->vdev.set_config = virtio_scsi_set_config;

    s->vdev.get_features = virtio_scsi_get_features;

    s->vdev.reset = virtio_scsi_reset;

    s->ctrl_vq = virtio_add_queue(&s->vdev, VIRTIO_SCSI_VQ_SIZE,

                                   virtio_scsi_handle_ctrl);

    s->event_vq = virtio_add_queue(&s->vdev, VIRTIO_SCSI_VQ_SIZE,

                                   virtio_scsi_handle_event);

    for (i = 0; i < s->conf->num_queues; i++) {

        s->cmd_vqs[i] = virtio_add_queue(&s->vdev, VIRTIO_SCSI_VQ_SIZE,

                                         virtio_scsi_handle_cmd);

    }

    scsi_bus_new(&s->bus, dev, &virtio_scsi_scsi_info);

    if (!dev->hotplugged) {

        scsi_bus_legacy_handle_cmdline(&s->bus);

    }

    register_savevm(dev, "virtio-scsi", virtio_scsi_id++, 1,

                    virtio_scsi_save, virtio_scsi_load, s);

    return &s->vdev;

}

void virtio_scsi_exit(VirtIODevice *vdev)

{

    VirtIOSCSI *s = (VirtIOSCSI *)vdev;

    unregister_savevm(s->qdev, "virtio-scsi", s);

    virtio_cleanup(vdev);

}