Re: [Qemu-devel] [PULL 05/47] contrib: add libvhost-user

[Michael S. Tsirkin]

On Thu, Nov 10, 2016 at 05:05:03PM +0000, Daniel P. Berrange wrote:
> On Thu, Nov 10, 2016 at 06:12:03PM +0200, Michael S. Tsirkin wrote:
> > From: Marc-André Lureau <address@hidden>
> > 
> > Add a library to help implementing vhost-user backend (or slave).
> > 
> > Dealing with vhost-user as an application developer isn't so easy: you
> > have all the trouble with any protocol: validation, unix ancillary data,
> > shared memory, eventfd, logging, and on top of that you need to deal
> > with virtio queues, if possible efficiently.
> > 
> > qemu test has a nice vhost-user testing application vhost-user-bridge,
> > which implements most of vhost-user, and virtio.c which implements
> > virtqueues manipulation. Based on these two, I tried to make a simple
> > library, reusable for tests or development of new vhost-user scenarios.
> 
> By "new vhost-user scenarios" does this mean facilitating creation of
> vhost user clients by out of tree 3rd parties ?

Just more tests at this point.

> Unless I'm missing something, the change doesn't actually build any
> .so of this code, so only thing that can use it right now is other
> QEMU code.
> 
> If we want 3rd parties to use this, then it seems to me that LGPLv2+ or
> even a BSD like license would be more applicable than GPLv2+. Also we
> would need to state what API/ABI stability guarantees we're going to
> provide and create a versioned ELF .so.

We can discuss this when someone tries to do this.

> In general this patch looks like it is something to propose in 2.9,
> rather than pushing feature work in post-freeze.
> 
> Regards,
> Daniel

>From my perspective, anything that helps find failures
at user systems during build and not when
running guests is a plus.

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