Re: [PATCH/RFC 0/1] Vhost User Cross Cable: Intro

[Michael S. Tsirkin]

On Wed, Jan 08, 2020 at 02:54:30AM +0100, V. wrote:
> Hi List,
> 
> For my VM setup I tend to use a lot of VM to VM single network links to do 
> routing, switching and bridging in VM's instead of the host.
> Also stemming from a silly fetish to sometimes use some OpenBSD VMs as 
> firewall, but that is besides the point here.
> I am using the standard, tested and true method of using a whole bunch  of 
> bridges, having 2 vhost taps each.
> This works and it's fast, but it is a nightmare to manage with all the 
> interfaces on the host.
> 
> So, I looked a bit into how I can improve this, basically coming down to "How 
> to connect 2 VM's together in a really fast and easy way".
> This however, is not as straightforward as I thought, without going the whole 
> route of OVS/Snabb/any other big feature bloated
> software switch.
> Cause really, all I want is to connect 2 VM's in a fast and easy way. 
> Shouldn't be that hard right?
> 
> Anyways, I end up finding tests/vhost-user-bridge.c, which is very nicely 
> doing half of what I wanted.

BTW you can easily run two vhost user bridges and connect them back to
back, right?

> After some doubling of the vhosts and eliminating udp, I came up with a Vhost 
> User Cross Cable. (patch in next post).

Hmm you forgot --thread=shallow so your posts aren't linked.



> It just opens 2 vhost sockets instead of 1 and does the forwarding between 
> them.
> A terrible hack and slash of vhost-user-bridge.c, probably now with bugs 
> causing the dead of many puppies and the end of humanity,
> but it works!

I think generally this approach has value, maybe a separate utility,
maybe as a flag for vhost-user-bridge.

-- 
MST