virtio: add feature checking helpers

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>

3 files changed, 11 insertions, 11 deletions

diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c
index 0936f65..5c7b8c2 100644
--- a/hw/virtio/dataplane/vring.c
+++ b/hw/virtio/dataplane/vring.c
@@ -105,7 +105,7 @@ void vring_teardown(Vring *vring, VirtIODevice *vdev, int n)
 /* Disable guest->host notifies */
 void vring_disable_notification(VirtIODevice *vdev, Vring *vring)
 {
-    if (!(vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX))) {
+    if (!virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
         vring_set_used_flags(vdev, vring, VRING_USED_F_NO_NOTIFY);
     }
 }
@@ -116,7 +116,7 @@ void vring_disable_notification(VirtIODevice *vdev, Vring *vring)
  */
 bool vring_enable_notification(VirtIODevice *vdev, Vring *vring)
 {
-    if (vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
+    if (virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
         vring_avail_event(&vring->vr) = vring->vr.avail->idx;
     } else {
         vring_clear_used_flags(vdev, vring, VRING_USED_F_NO_NOTIFY);
@@ -135,12 +135,12 @@ bool vring_should_notify(VirtIODevice *vdev, Vring *vring)
      * interrupts. */
     smp_mb();
 
-    if ((vdev->guest_features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY)) &&
+    if (virtio_has_feature(vdev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
         unlikely(!vring_more_avail(vdev, vring))) {
         return true;
     }
 
-    if (!(vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX))) {
+    if (!virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
         return !(vring_get_avail_flags(vdev, vring) &
                  VRING_AVAIL_F_NO_INTERRUPT);
     }
@@ -401,7 +401,7 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
 
     /* On success, increment avail index. */
     vring->last_avail_idx++;
-    if (vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
+    if (virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
         vring_avail_event(&vring->vr) = vring->last_avail_idx;
     }
 
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index 7bfbb75..21e449a 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -69,7 +69,7 @@ static inline void reset_stats(VirtIOBalloon *dev)
 static bool balloon_stats_supported(const VirtIOBalloon *s)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(s);
-    return vdev->guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ);
+    return virtio_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ);
 }
 
 static bool balloon_stats_enabled(const VirtIOBalloon *s)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index f783f31..3c6e430 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -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);
     }