vhost-scsi: expose the TYPE_FW_PATH_PROVIDER interface

In the way, we can make the bootindex property take effect.
At the meanwhile, the firmware path name of vhost-scsi is
"channel@channel/vhost-scsi@target,lun".
Signed-off-by: NGonglei <arei.gonglei@huawei.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

hw/scsi/vhost-scsi.c

@@ -24,6 +24,7 @@
 #include "hw/virtio/virtio-scsi.h"
 #include "hw/virtio/virtio-bus.h"
 #include "hw/virtio/virtio-access.h"
+#include "hw/fw-path-provider.h"
 
 /* Features supported by host kernel. */
 static const int kernel_feature_bits[] = {
@@ -271,6 +272,19 @@ static void vhost_scsi_unrealize(DeviceState *dev, Error **errp)
     virtio_scsi_common_unrealize(dev, errp);
 }
 
+/*
+ * Implementation of an interface to adjust firmware path
+ * for the bootindex property handling.
+ */
+static char *vhost_scsi_get_fw_dev_path(FWPathProvider *p, BusState *bus,
+                                        DeviceState *dev)
+{
+    VHostSCSI *s = VHOST_SCSI(dev);
+    /* format: channel@channel/vhost-scsi@target,lun */
+    return g_strdup_printf("channel@%x/%s@%x,%x", s->channel,
+                           qdev_fw_name(dev), s->target, s->lun);
+}
+
 static Property vhost_scsi_properties[] = {
     DEFINE_VHOST_SCSI_PROPERTIES(VHostSCSI, parent_obj.conf),
     DEFINE_PROP_END_OF_LIST(),
@@ -280,6 +294,7 @@ static void vhost_scsi_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
+    FWPathProviderClass *fwc = FW_PATH_PROVIDER_CLASS(klass);
 
     dc->props = vhost_scsi_properties;
     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
@@ -288,6 +303,7 @@ static void vhost_scsi_class_init(ObjectClass *klass, void *data)
     vdc->get_features = vhost_scsi_get_features;
     vdc->set_config = vhost_scsi_set_config;
     vdc->set_status = vhost_scsi_set_status;
+    fwc->get_dev_path = vhost_scsi_get_fw_dev_path;
 }
 
 static void vhost_scsi_instance_init(Object *obj)
@@ -304,6 +320,10 @@ static const TypeInfo vhost_scsi_info = {
     .instance_size = sizeof(VHostSCSI),
     .class_init = vhost_scsi_class_init,
     .instance_init = vhost_scsi_instance_init,
+    .interfaces = (InterfaceInfo[]) {
+        { TYPE_FW_PATH_PROVIDER },
+        { }
+    },
 };
 
 static void virtio_register_types(void)

include/hw/virtio/vhost-scsi.h

@@ -61,6 +61,9 @@ typedef struct VHostSCSI {
 
     struct vhost_dev dev;
     int32_t bootindex;
+    int channel;
+    int target;
+    int lun;
 } VHostSCSI;
 
 #define DEFINE_VHOST_SCSI_PROPERTIES(_state, _conf_field) \