On Tue, 16 Aug 2022 12:38:52 -0400 Michael S. Tsirkin wrote:

On Mon, Aug 15, 2022 at 10:56:06AM -0700, Bobby Eshleman wrote:

quoted

In order to support usage of qdisc on vsock traffic, this commit
introduces a struct net_device to vhost and virtio vsock.

Two new devices are created, vhost-vsock for vhost and virtio-vsock
for virtio. The devices are attached to the respective transports.

To bypass the usage of the device, the user may "down" the associated
network interface using common tools. For example, "ip link set dev
virtio-vsock down" lets vsock bypass the net_device and qdisc entirely,
simply using the FIFO logic of the prior implementation.  

Ugh. That's quite a hack. Mark my words, at some point we will decide to
have down mean "down".  Besides, multiple net devices with link up tend
to confuse userspace. So might want to keep it down at all times
even short term.

Agreed!

From a cursory look (and Documentation/ would be nice..) it feels
very wrong to me. Do you know of any uses of a netdev which would 
be semantically similar to what you're doing? Treating netdevs as
buildings blocks for arbitrary message passing solutions is something 
I dislike quite strongly.

Could you recommend where I can learn more about vsocks?