Support the event index feature in the virtio spec.
The results are less notifications between the guest and host, and in
result faster operation of the virt queues.
Signed-off-by: Sasha Levin <levinsasha928@xxxxxxxxx>
---
tools/kvm/include/kvm/virtio.h | 7 +++++++
1 files changed, 7 insertions(+), 0 deletions(-)
diff --git a/tools/kvm/include/kvm/virtio.h b/tools/kvm/include/kvm/virtio.h
index c6c380d..cd24285 100644
--- a/tools/kvm/include/kvm/virtio.h
+++ b/tools/kvm/include/kvm/virtio.h
@@ -38,6 +38,8 @@ static inline bool virt_queue__available(struct virt_queue *vq)
{
if (!vq->vring.avail)
return 0;
+
+ vring_avail_event(&vq->vring) = vq->last_avail_idx;
return vq->vring.avail->idx != vq->last_avail_idx;
}
@@ -51,6 +53,11 @@ static inline void *guest_pfn_to_host(struct kvm *kvm, u32 pfn)
return guest_flat_to_host(kvm, (unsigned long)pfn << VIRTIO_PCI_QUEUE_ADDR_SHIFT);
}
+static inline int virtio_queue__should_signal(struct virt_queue *vq)
+{
+ return vring_used_event(&vq->vring) <= vq->vring.used->idx;
+}
+
struct vring_used_elem *virt_queue__set_used_elem(struct virt_queue *queue, u32 head, u32 len);
u16 virt_queue__get_iov(struct virt_queue *queue, struct iovec iov[], u16 *out, u16 *in, struct kvm *kvm);
--
1.7.8.rc1
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