virtio-scsi: Move DEFINE_VIRTIO_SCSI_FEATURES to virtio-scsi

So far virtio-scsi-device can't expose host features to guest while
using virtio-mmio because it doesn't set DEFINE_VIRTIO_SCSI_FEATURES on
backend or transport.

The host features belong to the backends while virtio-scsi-pci,
virtio-scsi-s390 and virtio-scsi-ccw set the DEFINE_VIRTIO_SCSI_FEATURES
on transports. But they already have the ability to forward property
accesses to the backend child. So if we move the host features to
backends, it doesn't break the backwards compatibility for them and
make host features work while using virtio-mmio.

Move DEFINE_VIRTIO_SCSI_FEATURES to the backend virtio-scsi. The
transports just sync the host features from backends.

Signed-off-by: Shannon Zhao <zhaoshenglong@huawei.com>
Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index c9bea06..e242fef 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -631,6 +631,10 @@ static void virtio_scsi_set_config(VirtIODevice *vdev,
 static uint32_t virtio_scsi_get_features(VirtIODevice *vdev,
                                          uint32_t requested_features)
 {
+    VirtIOSCSI *s = VIRTIO_SCSI(vdev);
+
+    /* Firstly sync all virtio-scsi possible supported features */
+    requested_features |= s->host_features;
     return requested_features;
 }
 
@@ -945,6 +949,7 @@ static void virtio_scsi_device_unrealize(DeviceState *dev, Error **errp)
 
 static Property virtio_scsi_properties[] = {
     DEFINE_VIRTIO_SCSI_PROPERTIES(VirtIOSCSI, parent_obj.conf),
+    DEFINE_VIRTIO_SCSI_FEATURES(VirtIOSCSI, host_features),
     DEFINE_PROP_END_OF_LIST(),
 };