Live migration support for Cloud-Hypervisor VMs

Folks, We are implementing Live Migration support in "ch" driver of Libvirt. I'd like to confirm if the approach we have chosen would be accepted upstream once implemented. Our immediate goal is to implement "Hypervisor Native" + "Managed Direct" mode of migration. "Hypervisor Native" here referring to VMM(ch) being responsible for data flow. This in contrast to TUNNELED migration where data is sent over libvirt rpc. "Managed Direct" referring to virsh client responsible for control flow between source and dest hosts. The libvirtd daemons on source and destination do not have to communicate with each other. These modes are described further at https://libvirt.org/migration.html#network-data-transports. At the moment, Cloud-Hypervisor supports receiving migration data only on Unix Domain Sockets. Also, Cloud-Hypervisor does not encrypt the VM data while sending. We are considering forking "socat" processes as documented at https://github.com/cloud-hypervisor/cloud-hypervisor/blob/main/docs/live_.... The socat processes will be forked in "Prepare" and "Perform" phases on Destination and Source hosts respectively. I couldn't find any existing implementation in libvirt to connect Domain Sockets on different hosts. Please let me know, if you'd recommend a different approach from forking socat processes to connect Domain Sockets on source and dest hosts to allow Live VM Migration. FYI, I had an early discussion on this topic at https://gitlab.com/libvirt/libvirt/-/issues/352 and Peter suggested I follow here for broader discussion. Also Peter, rightly, suggested we look at enabling encryption of VM data in cloud-hypervisor. This is something we will follow up with after enabling Live Migration in Libvirt. -- Regards, Praveen K Paladugu