Subject: Re: [net-next v2 1/1] virtual-bus: Implementation of Virtual Bus

From: "Michael S. Tsirkin" <[email-masked]>
Date: Wed, 20 Nov 2019 08:43:20 -0500

On Wed, Nov 20, 2019 at 09:03:19AM -0400, Jason Gunthorpe wrote:
> On Wed, Nov 20, 2019 at 02:38:08AM -0500, Michael S. Tsirkin wrote:
> > > > I don't think that extends as far as actively encouraging userspace
> > > > drivers poking at hardware in a vendor specific way.  
> > > 
> > > Yes, it does, if you can implement your user space requirements using
> > > vfio then why do you need a kernel driver?
> > 
> > People's requirements differ. You are happy with just pass through a VF
> > you can already use it. Case closed. There are enough people who have
> > a fixed userspace that people have built virtio accelerators,
> > now there's value in supporting that, and a vendor specific
> > userspace blob is not supporting that requirement.
> 
> I have no idea what you are trying to explain here. I'm not advocating
> for vfio pass through.

You seem to come from an RDMA background, used to userspace linking to
vendor libraries to do basic things like push bits out on the network,
because users live on the performance edge and rebuild their
userspace often anyway.

Lots of people are not like that, they would rather have the
vendor-specific driver live in the kernel, with userspace being
portable, thank you very much.

-- 
MST