On Tue, Feb 11, 2020 at 11:25:32AM +0100, Stefano Garzarella wrote:

Do you want to mention that loopback works in the guest and on the host
since Linux vX.Y and before that it only worked inside the guest?

> @@ -164,6 +164,16 @@ Consider using
>  .B VMADDR_CID_ANY
>  when binding instead of getting the local CID with
>  .BR IOCTL_VM_SOCKETS_GET_LOCAL_CID .
> +.SS Local communication
> +The
> +.B VMADDR_CID_LOCAL
> +(1) can be used to address itself. In this case all packets are redirected
> +to the same host that generated them. Useful for testing and debugging.

This can be rephrased more naturally:

.B VMADDR_CID_LOCAL
(1) directs packets to the same host that generated them. This is useful
for testing applications on a single host and for debugging.