Re: [PATCH v3 00/21] KVM: Dirty ring interface

[Paolo Bonzini]

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