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>
This commit is contained in:
Cornelia Huck 2014-12-11 14:25:05 +01:00 committed by Michael S. Tsirkin
parent a590fd5ba8
commit 0cd09c3a6c
8 changed files with 44 additions and 32 deletions

View file

@ -743,8 +743,8 @@ static int virtio_ccw_device_init(VirtioCcwDevice *dev, VirtIODevice *vdev)
dev->host_features[0] = virtio_bus_get_vdev_features(&dev->bus,
dev->host_features[0]);
dev->host_features[0] |= 0x1 << VIRTIO_F_NOTIFY_ON_EMPTY;
dev->host_features[0] |= 0x1 << VIRTIO_F_BAD_FEATURE;
virtio_add_feature(&dev->host_features[0], VIRTIO_F_NOTIFY_ON_EMPTY);
virtio_add_feature(&dev->host_features[0], VIRTIO_F_BAD_FEATURE);
css_generate_sch_crws(sch->cssid, sch->ssid, sch->schid,
parent->hotplugged, 1);