This patch is the base for enabling support for event index feature in the virtio spec.
We do so by updating and evaluating the used/avail event idx in the virtio ring functions.
Actual usage of this flag is in the following patches.
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
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
