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>

1 files changed, 5 insertions, 5 deletions

diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c
index 0936f659e5..5c7b8c20fa 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;
     }