On 09/01/20 20:13, Michael S. Tsirkin wrote: > That's one of the reasons I called for using something > resembling vring_packed_desc. In principle it could make sense to use the ring-wrap detection mechanism from vring_packed_desc instead of the producer/consumer indices. However, the element address/length indirection is unnecessary. Also, unlike virtio, KVM needs to know if there are N free entries (N is ~512) before running a guest. I'm not sure if that is possible with ring-wrap counters, while it's trivial with producer/consumer indices. Paolo
