RE: [RFC] hypercall-vsock: add a new vsock transport

["Wang, Wei W" <wei.w.wang@intel.com>]

> From: Stefan Hajnoczi <stefanha@redhat.com>
On Wednesday, November 10, 2021 5:35 PM, Stefan Hajnoczi wrote:
> AF_VSOCK is designed to allow multiple transports, so why not. There is a cost
> to developing and maintaining a vsock transport though.

Yes. The effort could be reduced via simplifying the design as much as possible:
e.g. no ring operations - guest just sends a packet each time for the host to read.
(this transport isn't targeting for high performance)

> 
> I think Amazon Nitro enclaves use virtio-vsock and I've CCed Andra in case she
> has thoughts on the pros/cons and how to minimize the trusted computing
> base.

Thanks for adding more related person to the discussion loop.

> 
> If simplicity is the top priority then VIRTIO's MMIO transport without indirect
> descriptors and using the packed virtqueue layout reduces the size of the
> implementation:
> https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/virtio-v1.1-cs01.html#x1-1
> 440002

I listed some considerations for virtio-mmio in the response to Michael.
Please have a check if any different thoughts.

Thanks,
Wei