On Mon, Jan 15, 2018 at 02:56:31PM +0800, Jason Wang wrote:
On 2018年01月12日 18:18, Stefan Hajnoczi wrote:
And what's more important, according to the kvm 2016 slides of vhost-pci,
the motivation of vhost-pci is not building SDN but a chain of VNFs. So
bypassing the central vswitch through a private VM2VM path does make sense.
(Though whether or not vhost-pci is the best choice is still questionable).
This is probably my fault. Maybe my networking terminology is wrong. I
consider "virtual network functions" to be part of "software-defined
networking" use cases. I'm not implying there must be a central virtual
switch.
To rephrase: vhost-pci enables exitless VM2VM communication.
The problem is, exitless is not what vhost-pci invents, it could be achieved
now when both sides are doing busypolling.
The only way I'm aware of is ivshmem. But ivshmem lacks a family of
standard device types that allows different implementations to
interoperate. We already have the virtio family of device types, so it
makes sense to work on a virtio-based solution.
Perhaps I've missed a different approach for exitless VM2VM
communication. Please explain how VM1 and VM2 can do exitless network
communication today?