virtio: feature bit manipulation helpers

Add virtio_{add,clear}_feature helper functions for manipulating a
feature bits variable. This has some benefits over open coding:
- add check that the bit is in a sane range
- make it obvious at a glance what is going on
- have a central point to change when we want to extend feature bits

Convert existing code manipulating features to use the new helpers.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
index a2bac9b..2365336 100644
--- a/hw/char/virtio-serial-bus.c
+++ b/hw/char/virtio-serial-bus.c
@@ -475,7 +475,7 @@ static uint32_t get_features(VirtIODevice *vdev, uint32_t features)
     vser = VIRTIO_SERIAL(vdev);
 
     if (vser->bus.max_nr_ports > 1) {
-        features |= (1 << VIRTIO_CONSOLE_F_MULTIPORT);
+        virtio_add_feature(&features, VIRTIO_CONSOLE_F_MULTIPORT);
     }
     return features;
 }