diff --git a/hw/scsi-bus.c b/hw/scsi-bus.c
index 8f0d7e6..cabdb3c 100644
--- a/hw/scsi-bus.c
+++ b/hw/scsi-bus.c
@@ -23,32 +23,29 @@ static struct BusInfo scsi_bus_info = {
 };
 static int next_scsi_bus;
 
-static int scsi_device_init(SCSIDevice *dev)
+static int scsi_device_init(SCSIDevice *s)
 {
-    SCSIDeviceInfo *info = DO_UPCAST(SCSIDeviceInfo, qdev,
-                                     qdev_get_info(DEVICE(dev)));
-    if (info->init) {
-        return info->init(dev);
+    SCSIDeviceClass *sc = SCSI_DEVICE_GET_CLASS(s);
+    if (sc->init) {
+        return sc->init(s);
     }
     return 0;
 }
 
 static void scsi_device_destroy(SCSIDevice *s)
 {
-    SCSIDeviceInfo *info = DO_UPCAST(SCSIDeviceInfo, qdev,
-                                     qdev_get_info(DEVICE(s)));
-    if (info->destroy) {
-        info->destroy(s);
+    SCSIDeviceClass *sc = SCSI_DEVICE_GET_CLASS(s);
+    if (sc->destroy) {
+        sc->destroy(s);
     }
 }
 
 static SCSIRequest *scsi_device_alloc_req(SCSIDevice *s, uint32_t tag, uint32_t lun,
                                           uint8_t *buf, void *hba_private)
 {
-    SCSIDeviceInfo *info = DO_UPCAST(SCSIDeviceInfo, qdev,
-                                     qdev_get_info(DEVICE(s)));
-    if (info->alloc_req) {
-        return info->alloc_req(s, tag, lun, buf, hba_private);
+    SCSIDeviceClass *sc = SCSI_DEVICE_GET_CLASS(s);
+    if (sc->alloc_req) {
+        return sc->alloc_req(s, tag, lun, buf, hba_private);
     }
 
     return NULL;
@@ -56,10 +53,9 @@ static SCSIRequest *scsi_device_alloc_req(SCSIDevice *s, uint32_t tag, uint32_t
 
 static void scsi_device_unit_attention_reported(SCSIDevice *s)
 {
-    SCSIDeviceInfo *info = DO_UPCAST(SCSIDeviceInfo, qdev,
-                                     qdev_get_info(DEVICE(s)));
-    if (info->unit_attention_reported) {
-        info->unit_attention_reported(s);
+    SCSIDeviceClass *sc = SCSI_DEVICE_GET_CLASS(s);
+    if (sc->unit_attention_reported) {
+        sc->unit_attention_reported(s);
     }
 }
 
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 673948c..9944d69 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -1729,75 +1729,108 @@ static SCSIRequest *scsi_block_new_request(SCSIDevice *d, uint32_t tag,
     DEFINE_PROP_STRING("ver",  SCSIDiskState, version),         \
     DEFINE_PROP_STRING("serial",  SCSIDiskState, serial)
 
-static SCSIDeviceInfo scsi_disk_info[] = {
-    {
-        .qdev.name    = "scsi-hd",
-        .qdev.fw_name = "disk",
-        .qdev.desc    = "virtual SCSI disk",
-        .qdev.size    = sizeof(SCSIDiskState),
-        .qdev.reset   = scsi_disk_reset,
-        .init         = scsi_hd_initfn,
-        .destroy      = scsi_destroy,
-        .alloc_req    = scsi_new_request,
-        .unit_attention_reported = scsi_disk_unit_attention_reported,
-        .qdev.props   = (Property[]) {
-            DEFINE_SCSI_DISK_PROPERTIES(),
-            DEFINE_PROP_BIT("removable", SCSIDiskState, removable, 0, false),
-            DEFINE_PROP_END_OF_LIST(),
-        }
-    },{
-        .qdev.name    = "scsi-cd",
-        .qdev.fw_name = "disk",
-        .qdev.desc    = "virtual SCSI CD-ROM",
-        .qdev.size    = sizeof(SCSIDiskState),
-        .qdev.reset   = scsi_disk_reset,
-        .init         = scsi_cd_initfn,
-        .destroy      = scsi_destroy,
-        .alloc_req    = scsi_new_request,
-        .unit_attention_reported = scsi_disk_unit_attention_reported,
-        .qdev.props   = (Property[]) {
-            DEFINE_SCSI_DISK_PROPERTIES(),
-            DEFINE_PROP_END_OF_LIST(),
-        },
+static void scsi_hd_class_initfn(ObjectClass *klass, void *data)
+{
+    SCSIDeviceClass *sc = SCSI_DEVICE_CLASS(klass);
+
+    sc->init         = scsi_hd_initfn;
+    sc->destroy      = scsi_destroy;
+    sc->alloc_req    = scsi_new_request;
+    sc->unit_attention_reported = scsi_disk_unit_attention_reported;
+}
+
+static SCSIDeviceInfo scsi_hd_info = {
+    .qdev.name    = "scsi-hd",
+    .qdev.fw_name = "disk",
+    .qdev.desc    = "virtual SCSI disk",
+    .qdev.size    = sizeof(SCSIDiskState),
+    .qdev.reset   = scsi_disk_reset,
+    .qdev.class_init = scsi_hd_class_initfn,
+    .qdev.props   = (Property[]) {
+        DEFINE_SCSI_DISK_PROPERTIES(),
+        DEFINE_PROP_BIT("removable", SCSIDiskState, removable, 0, false),
+        DEFINE_PROP_END_OF_LIST(),
+    },
+};
+
+static void scsi_cd_class_initfn(ObjectClass *klass, void *data)
+{
+    SCSIDeviceClass *sc = SCSI_DEVICE_CLASS(klass);
+
+    sc->init         = scsi_cd_initfn;
+    sc->destroy      = scsi_destroy;
+    sc->alloc_req    = scsi_new_request;
+    sc->unit_attention_reported = scsi_disk_unit_attention_reported;
+}
+
+static SCSIDeviceInfo scsi_cd_info = {
+    .qdev.name    = "scsi-cd",
+    .qdev.fw_name = "disk",
+    .qdev.desc    = "virtual SCSI CD-ROM",
+    .qdev.size    = sizeof(SCSIDiskState),
+    .qdev.reset   = scsi_disk_reset,
+    .qdev.class_init = scsi_cd_class_initfn,
+    .qdev.props   = (Property[]) {
+        DEFINE_SCSI_DISK_PROPERTIES(),
+        DEFINE_PROP_END_OF_LIST(),
+    },
+};
+
 #ifdef __linux__
-    },{
-        .qdev.name    = "scsi-block",
-        .qdev.fw_name = "disk",
-        .qdev.desc    = "SCSI block device passthrough",
-        .qdev.size    = sizeof(SCSIDiskState),
-        .qdev.reset   = scsi_disk_reset,
-        .init         = scsi_block_initfn,
-        .destroy      = scsi_destroy,
-        .alloc_req    = scsi_block_new_request,
-        .qdev.props   = (Property[]) {
-            DEFINE_SCSI_DISK_PROPERTIES(),
-            DEFINE_PROP_END_OF_LIST(),
-        },
+static void scsi_block_class_initfn(ObjectClass *klass, void *data)
+{
+    SCSIDeviceClass *sc = SCSI_DEVICE_CLASS(klass);
+
+    sc->init         = scsi_block_initfn;
+    sc->destroy      = scsi_destroy;
+    sc->alloc_req    = scsi_block_new_request;
+}
+
+static SCSIDeviceInfo scsi_block_info = {
+    .qdev.name    = "scsi-block",
+    .qdev.fw_name = "disk",
+    .qdev.desc    = "SCSI block device passthrough",
+    .qdev.size    = sizeof(SCSIDiskState),
+    .qdev.reset   = scsi_disk_reset,
+    .qdev.class_init = scsi_block_class_initfn,
+    .qdev.props   = (Property[]) {
+        DEFINE_SCSI_DISK_PROPERTIES(),
+        DEFINE_PROP_END_OF_LIST(),
+    },
+};
 #endif
-    },{
-        .qdev.name    = "scsi-disk", /* legacy -device scsi-disk */
-        .qdev.fw_name = "disk",
-        .qdev.desc    = "virtual SCSI disk or CD-ROM (legacy)",
-        .qdev.size    = sizeof(SCSIDiskState),
-        .qdev.reset   = scsi_disk_reset,
-        .init         = scsi_disk_initfn,
-        .destroy      = scsi_destroy,
-        .alloc_req    = scsi_new_request,
-        .unit_attention_reported = scsi_disk_unit_attention_reported,
-        .qdev.props   = (Property[]) {
-            DEFINE_SCSI_DISK_PROPERTIES(),
-            DEFINE_PROP_BIT("removable", SCSIDiskState, removable, 0, false),
-            DEFINE_PROP_END_OF_LIST(),
-        }
+
+static void scsi_disk_class_initfn(ObjectClass *klass, void *data)
+{
+    SCSIDeviceClass *sc = SCSI_DEVICE_CLASS(klass);
+
+    sc->init         = scsi_disk_initfn;
+    sc->destroy      = scsi_destroy;
+    sc->alloc_req    = scsi_new_request;
+    sc->unit_attention_reported = scsi_disk_unit_attention_reported;
+}
+
+static SCSIDeviceInfo scsi_disk_info = {
+    .qdev.name    = "scsi-disk", /* legacy -device scsi-disk */
+    .qdev.fw_name = "disk",
+    .qdev.desc    = "virtual SCSI disk or CD-ROM (legacy)",
+    .qdev.size    = sizeof(SCSIDiskState),
+    .qdev.reset   = scsi_disk_reset,
+    .qdev.class_init = scsi_disk_class_initfn,
+    .qdev.props   = (Property[]) {
+        DEFINE_SCSI_DISK_PROPERTIES(),
+        DEFINE_PROP_BIT("removable", SCSIDiskState, removable, 0, false),
+        DEFINE_PROP_END_OF_LIST(),
     }
 };
 
 static void scsi_disk_register_devices(void)
 {
-    int i;
-
-    for (i = 0; i < ARRAY_SIZE(scsi_disk_info); i++) {
-        scsi_qdev_register(&scsi_disk_info[i]);
-    }
+    scsi_qdev_register(&scsi_hd_info);
+    scsi_qdev_register(&scsi_cd_info);
+#ifdef __linux__
+    scsi_qdev_register(&scsi_block_info);
+#endif
+    scsi_qdev_register(&scsi_disk_info);
 }
 device_init(scsi_disk_register_devices)
diff --git a/hw/scsi-generic.c b/hw/scsi-generic.c
index ef76e4b..9fb2a09 100644
--- a/hw/scsi-generic.c
+++ b/hw/scsi-generic.c
@@ -461,15 +461,22 @@ static SCSIRequest *scsi_new_request(SCSIDevice *d, uint32_t tag, uint32_t lun,
     return req;
 }
 
+static void scsi_generic_class_initfn(ObjectClass *klass, void *data)
+{
+    SCSIDeviceClass *sc = SCSI_DEVICE_CLASS(klass);
+
+    sc->init         = scsi_generic_initfn;
+    sc->destroy      = scsi_destroy;
+    sc->alloc_req    = scsi_new_request;
+}
+
 static SCSIDeviceInfo scsi_generic_info = {
     .qdev.name    = "scsi-generic",
     .qdev.fw_name = "disk",
     .qdev.desc    = "pass through generic scsi device (/dev/sg*)",
     .qdev.size    = sizeof(SCSIDevice),
     .qdev.reset   = scsi_generic_reset,
-    .init         = scsi_generic_initfn,
-    .destroy      = scsi_destroy,
-    .alloc_req    = scsi_new_request,
+    .qdev.class_init = scsi_generic_class_initfn,
     .qdev.props   = (Property[]) {
         DEFINE_BLOCK_PROPERTIES(SCSIDevice, conf),
         DEFINE_PROP_END_OF_LIST(),
diff --git a/hw/scsi.h b/hw/scsi.h
index 0d24d41..41501f2 100644
--- a/hw/scsi.h
+++ b/hw/scsi.h
@@ -68,6 +68,11 @@ struct SCSIRequest {
 
 typedef struct SCSIDeviceClass {
     DeviceClass parent_class;
+    int (*init)(SCSIDevice *dev);
+    void (*destroy)(SCSIDevice *s);
+    SCSIRequest *(*alloc_req)(SCSIDevice *s, uint32_t tag, uint32_t lun,
+                              uint8_t *buf, void *hba_private);
+    void (*unit_attention_reported)(SCSIDevice *s);
 } SCSIDeviceClass;
 
 struct SCSIDevice
@@ -104,14 +109,8 @@ struct SCSIReqOps {
     uint8_t *(*get_buf)(SCSIRequest *req);
 };
 
-typedef int (*scsi_qdev_initfn)(SCSIDevice *dev);
 struct SCSIDeviceInfo {
     DeviceInfo qdev;
-    scsi_qdev_initfn init;
-    void (*destroy)(SCSIDevice *s);
-    SCSIRequest *(*alloc_req)(SCSIDevice *s, uint32_t tag, uint32_t lun,
-                              uint8_t *buf, void *hba_private);
-    void (*unit_attention_reported)(SCSIDevice *s);
 };
 
 struct SCSIBusInfo {
