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: qemu-stable@nongnu.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
(cherry picked from commit 2a083ffd2e37ef08769749a5c7cfc6ca65c9f8ea)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 01f1351554aae439215a8a34a2cc9ab974d2d6b0..abc48d8b2e4d4d2b45b0d15afabec7a4956e3617 100644 (file)
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1904,6 +1904,7 @@ 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 = {