virtio-net: mark VIRTIO_NET_F_GSO as legacy

virtio 1.0 spec says this is a legacy feature bit,
hide it from guests in modern mode.

Note: for cross-version migration compatibility,
we keep the bit set in host_features.
The result will be that a guest migrating cross-version
will see host features change under it.
As guests only seem to read it once, this should
not be an issue. Meanwhile, will work to fix guests to
ignore this bit in virtio1 mode, too.

Cc: [email protected]
Signed-off-by: Michael S. Tsirkin <[email protected]>
Reviewed-by: Cornelia Huck <[email protected]>

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 20aa63e16cc121d7d0c45462cbb849ec5ab885dc..b68c69d8f6f1fda609ee370192c53947b19f8870 100644 (file)
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1942,6 +1942,7 @@ static void virtio_net_class_init(ObjectClass *klass, void *data)
     vdc->guest_notifier_pending = virtio_net_guest_notifier_pending;
     vdc->load = virtio_net_load_device;
     vdc->save = virtio_net_save_device;
+    vdc->legacy_features |= (0x1 << VIRTIO_NET_F_GSO);
 }
 
 static const TypeInfo virtio_net_info = {