On 2018年01月20日 01:20, Stefan Hajnoczi wrote:
I don't propose any new idea. I just want to know what's the advantage of
vhost-pci over zerocopy. Both needs one time of copy, the difference is the
vhost-pci did it inside a guest but zerocopy did in on host.
Exitless VM2VM communication is desirable if you cannot run software on
the host or if both endpoints are already in VMs. In that case running
one thing in a VM and another on the host doesn't make sense.
Well, I must have missed anything, I don't see why we can not run
virtio-net backend on host. Especially it only does L2 stuffs, higher
level of service could be provided by another VM for sure. So it looks
to me virtio-vhost-user is just a split device implementation which is
irreverent to the service it could provide.
Maybe you can provide a concrete examples of virtio-vhost-user and its
advantages?
The obvious environment where this applies is in the cloud where
everything is a VM.
So a typical setup makes the VMs can already talk to each other through
ethernet(virtio-net). Virtio-vhost-user looks much less flexible than
exist stuffs. The only possible advantage of virtio-vhost-user is its
performance or security which still need to be proved.
Thanks
