Subject: Re: [PATCH V2 3/5] vDPA: introduce vDPA bus

From: Tiwei Bie <[email-masked]>
Date: Wed, 19 Feb 2020 10:59:48 +0800

On Tue, Feb 18, 2020 at 01:56:12PM +0000, Jason Gunthorpe wrote:
> On Mon, Feb 17, 2020 at 02:08:03PM +0800, Jason Wang wrote:
> 
> > I thought you were copied in the patch [1], maybe we can move vhost related
> > discussion there to avoid confusion.
> >
> > [1] https://lwn.net/Articles/811210/
> 
> Wow, that is .. confusing.
> 
> So this is supposed to duplicate the uAPI of vhost-user? But it is
> open coded and duplicated because .. vdpa?

Do you mean the vhost-user in DPDK? There is no vhost-user
in Linux kernel.

Thanks,
Tiwei

> 
> > So it's cheaper and simpler to introduce a new bus instead of refactoring a
> > well known bus and API where brunches of drivers and devices had been
> > implemented for years.
> 
> If you reason for this approach is to ease the implementation then you
> should talk about it in the cover letters/etc
> 
> Maybe it is reasonable to do this because the rework is too great, I
> don't know, but to me this whole thing looks rather messy. 
> 
> Remember this stuff is all uAPI as it shows up in sysfs, so you can
> easilly get stuck with it forever.
> 
> Jason