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virtio: add feature checking helpers

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Add a helper function for checking whether a bit is set in the guest
features for a vdev as well as one that works on a feature bit set.

Convert code that open-coded this: It cleans up the code and makes it
easier to extend the guest feature bits.

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 14:25:06 +01:00 • committed by Michael S. Tsirkin
parent 0cd09c3a6c
commit ef546f1275
8 changed files with 42 additions and 31 deletions
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10
hw/virtio/virtio.c
View file

@ -217,7 +217,7 @@ static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val)
void virtio_queue_set_notification(VirtQueue *vq, int enable)
{
vq->notification = enable;
if (vq->vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
if (virtio_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
vring_set_avail_event(vq, vring_avail_idx(vq));
} else if (enable) {
vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY);
@ -468,7 +468,7 @@ int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
max = vq->vring.num;
i = head = virtqueue_get_head(vq, vq->last_avail_idx++);
if (vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
if (virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
vring_set_avail_event(vq, vq->last_avail_idx);
}
@ -826,12 +826,12 @@ static bool vring_notify(VirtIODevice *vdev, VirtQueue *vq)
/* We need to expose used array entries before checking used event. */
smp_mb();
/* Always notify when queue is empty (when feature acknowledge) */
if (((vdev->guest_features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY)) &&
!vq->inuse && vring_avail_idx(vq) == vq->last_avail_idx)) {
if (virtio_has_feature(vdev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
!vq->inuse && vring_avail_idx(vq) == vq->last_avail_idx) {
return true;
}
if (!(vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX))) {
if (!virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT);
}