hw: move virtio devices to hw/ subdirectories

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

2 files changed, 775 insertions, 0 deletions

diff --git a/hw/scsi/Makefile.objs b/hw/scsi/Makefile.objs
index 6a56504..b76b9c3 100644
--- a/hw/scsi/Makefile.objs
+++ b/hw/scsi/Makefile.objs
@@ -4,3 +4,4 @@ common-obj-$(CONFIG_LSI_SCSI_PCI) += lsi53c895a.o
 common-obj-$(CONFIG_MEGASAS_SCSI_PCI) += megasas.o
 common-obj-$(CONFIG_ESP) += esp.o
 common-obj-$(CONFIG_ESP_PCI) += esp-pci.o
+obj-$(CONFIG_VIRTIO) += virtio-scsi.o
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
new file mode 100644
index 0000000..ead7cda
--- /dev/null
+++ b/hw/scsi/virtio-scsi.c
@@ -0,0 +1,774 @@
+/*
+ * 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 "hw/virtio/virtio-scsi.h"
+#include "qemu/error-report.h"
+#include <hw/scsi/scsi.h>
+#include <block/scsi.h>
+#include <hw/virtio/virtio-bus.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
+#define VIRTIO_SCSI_T_PARAM_CHANGE             3
+
+/* Reasons for transport reset event */
+#define VIRTIO_SCSI_EVT_RESET_HARD             0
+#define VIRTIO_SCSI_EVT_RESET_RESCAN           1
+#define VIRTIO_SCSI_EVT_RESET_REMOVED          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 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;
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
+    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(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,
+                                   hwaddr *addr, int num)
+{
+    qemu_sglist_init(qsgl, num, &dma_context_memory);
+    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.in_num);
+    req->vq = vq;
+    req->dev = s;
+    req->sreq = NULL;
+    if (req->elem.out_num) {
+        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) {
+            VirtIOSCSIReq *cmd_req = r->hba_private;
+            if (cmd_req && cmd_req->req.cmd->tag == req->req.tmf->tag) {
+                break;
+            }
+        }
+        if (r) {
+            /*
+             * Assert that the request has not been completed yet, we
+             * check for it in the loop above.
+             */
+            assert(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_command_complete(SCSIRequest *r, uint32_t status,
+                                         size_t resid)
+{
+    VirtIOSCSIReq *req = r->hba_private;
+    uint32_t sense_len;
+
+    req->resp.cmd->response = VIRTIO_SCSI_S_OK;
+    req->resp.cmd->status = status;
+    if (req->resp.cmd->status == GOOD) {
+        req->resp.cmd->resid = tswap32(resid);
+    } else {
+        req->resp.cmd->resid = 0;
+        sense_len = scsi_req_get_sense(r, req->resp.cmd->sense,
+                                       VIRTIO_SCSI_SENSE_SIZE);
+        req->resp.cmd->sense_len = tswap32(sense_len);
+    }
+    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);
+    stw_raw(&scsiconf->max_channel, VIRTIO_SCSI_MAX_CHANNEL);
+    stw_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->resetting++;
+    qbus_reset_all(&s->bus.qbus);
+    s->resetting--;
+
+    s->sense_size = VIRTIO_SCSI_SENSE_SIZE;
+    s->cdb_size = VIRTIO_SCSI_CDB_SIZE;
+    s->events_dropped = false;
+}
+
+/* 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)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
+    virtio_save(vdev, f);
+}
+
+static int virtio_scsi_load(QEMUFile *f, void *opaque, int version_id)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
+    int ret;
+
+    ret = virtio_load(vdev, f);
+    if (ret) {
+        return ret;
+    }
+    return 0;
+}
+
+static void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev,
+                                   uint32_t event, uint32_t reason)
+{
+    VirtIOSCSIReq *req = virtio_scsi_pop_req(s, s->event_vq);
+    VirtIOSCSIEvent *evt;
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
+    int in_size;
+
+    if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) {
+        return;
+    }
+
+    if (!req) {
+        s->events_dropped = true;
+        return;
+    }
+
+    if (req->elem.out_num || req->elem.in_num != 1) {
+        virtio_scsi_bad_req();
+    }
+
+    if (s->events_dropped) {
+        event |= VIRTIO_SCSI_T_EVENTS_MISSED;
+        s->events_dropped = false;
+    }
+
+    in_size = req->elem.in_sg[0].iov_len;
+    if (in_size < sizeof(VirtIOSCSIEvent)) {
+        virtio_scsi_bad_req();
+    }
+
+    evt = req->resp.event;
+    memset(evt, 0, sizeof(VirtIOSCSIEvent));
+    evt->event = event;
+    evt->reason = reason;
+    if (!dev) {
+        assert(event == VIRTIO_SCSI_T_NO_EVENT);
+    } else {
+        evt->lun[0] = 1;
+        evt->lun[1] = dev->id;
+
+        /* Linux wants us to keep the same encoding we use for REPORT LUNS.  */
+        if (dev->lun >= 256) {
+            evt->lun[2] = (dev->lun >> 8) | 0x40;
+        }
+        evt->lun[3] = dev->lun & 0xFF;
+    }
+    virtio_scsi_complete_req(req);
+}
+
+static void virtio_scsi_handle_event(VirtIODevice *vdev, VirtQueue *vq)
+{
+    VirtIOSCSI *s = VIRTIO_SCSI(vdev);
+
+    if (s->events_dropped) {
+        virtio_scsi_push_event(s, NULL, VIRTIO_SCSI_T_NO_EVENT, 0);
+    }
+}
+
+static void virtio_scsi_change(SCSIBus *bus, SCSIDevice *dev, SCSISense sense)
+{
+    VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
+
+    if (((vdev->guest_features >> VIRTIO_SCSI_F_CHANGE) & 1) &&
+        dev->type != TYPE_ROM) {
+        virtio_scsi_push_event(s, dev, VIRTIO_SCSI_T_PARAM_CHANGE,
+                               sense.asc | (sense.ascq << 8));
+    }
+}
+
+static void virtio_scsi_hotplug(SCSIBus *bus, SCSIDevice *dev)
+{
+    VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
+
+    if ((vdev->guest_features >> VIRTIO_SCSI_F_HOTPLUG) & 1) {
+        virtio_scsi_push_event(s, dev, VIRTIO_SCSI_T_TRANSPORT_RESET,
+                               VIRTIO_SCSI_EVT_RESET_RESCAN);
+    }
+}
+
+static void virtio_scsi_hot_unplug(SCSIBus *bus, SCSIDevice *dev)
+{
+    VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
+
+    if ((vdev->guest_features >> VIRTIO_SCSI_F_HOTPLUG) & 1) {
+        virtio_scsi_push_event(s, dev, VIRTIO_SCSI_T_TRANSPORT_RESET,
+                               VIRTIO_SCSI_EVT_RESET_REMOVED);
+    }
+}
+
+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,
+    .change = virtio_scsi_change,
+    .hotplug = virtio_scsi_hotplug,
+    .hot_unplug = virtio_scsi_hot_unplug,
+    .get_sg_list = virtio_scsi_get_sg_list,
+    .save_request = virtio_scsi_save_request,
+    .load_request = virtio_scsi_load_request,
+};
+
+static int virtio_scsi_device_init(VirtIODevice *vdev)
+{
+    DeviceState *qdev = DEVICE(vdev);
+    VirtIOSCSI *s = VIRTIO_SCSI(vdev);
+    static int virtio_scsi_id;
+    int i;
+
+    virtio_init(VIRTIO_DEVICE(s), "virtio-scsi", VIRTIO_ID_SCSI,
+                sizeof(VirtIOSCSIConfig));
+
+    s->cmd_vqs = g_malloc0(s->conf.num_queues * sizeof(VirtQueue *));
+
+    /* TODO set up vdev function pointers */
+    vdev->get_config = virtio_scsi_get_config;
+    vdev->set_config = virtio_scsi_set_config;
+    vdev->get_features = virtio_scsi_get_features;
+    vdev->reset = virtio_scsi_reset;
+
+    s->ctrl_vq = virtio_add_queue(vdev, VIRTIO_SCSI_VQ_SIZE,
+                                  virtio_scsi_handle_ctrl);
+    s->event_vq = virtio_add_queue(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(vdev, VIRTIO_SCSI_VQ_SIZE,
+                                         virtio_scsi_handle_cmd);
+    }
+
+    scsi_bus_new(&s->bus, qdev, &virtio_scsi_scsi_info);
+    if (!qdev->hotplugged) {
+        scsi_bus_legacy_handle_cmdline(&s->bus);
+    }
+
+    register_savevm(qdev, "virtio-scsi", virtio_scsi_id++, 1,
+                    virtio_scsi_save, virtio_scsi_load, s);
+
+    return 0;
+}
+
+static int virtio_scsi_device_exit(DeviceState *qdev)
+{
+    VirtIOSCSI *s = VIRTIO_SCSI(qdev);
+    VirtIODevice *vdev = VIRTIO_DEVICE(qdev);
+
+    unregister_savevm(qdev, "virtio-scsi", s);
+    g_free(s->cmd_vqs);
+    virtio_common_cleanup(vdev);
+    return 0;
+}
+
+static Property virtio_scsi_properties[] = {
+    DEFINE_VIRTIO_SCSI_PROPERTIES(VirtIOSCSI, conf),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void virtio_scsi_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
+    dc->exit = virtio_scsi_device_exit;
+    dc->props = virtio_scsi_properties;
+    vdc->init = virtio_scsi_device_init;
+    vdc->get_config = virtio_scsi_get_config;
+    vdc->set_config = virtio_scsi_set_config;
+    vdc->get_features = virtio_scsi_get_features;
+    vdc->reset = virtio_scsi_reset;
+}
+
+static const TypeInfo virtio_scsi_info = {
+    .name = TYPE_VIRTIO_SCSI,
+    .parent = TYPE_VIRTIO_DEVICE,
+    .instance_size = sizeof(VirtIOSCSI),
+    .class_init = virtio_scsi_class_init,
+};
+
+static void virtio_register_types(void)
+{
+    type_register_static(&virtio_scsi_info);
+}
+
+type_init(virtio_register_types)