Re: [PATCH 0/2] virtio: Add vhost-user-gpio device's support

[Michael S. Tsirkin]

On Thu, Jan 20, 2022 at 09:32:34AM +0530, Viresh Kumar wrote:
> On 17-01-22, 10:11, Alex Bennée wrote:
> > 
> > "Michael S. Tsirkin" <mst@redhat.com> writes:
> > 
> > > On Wed, Jan 12, 2022 at 05:04:57PM +0530, Viresh Kumar wrote:
> > >> Hello,
> > >> 
> > >> This patchset adds vhost-user-gpio device's support in Qemu. The support 
> > >> for the
> > >> same has already been added to virtio specification and Linux Kernel.
> > >> 
> > >> A Rust based backend is also in progress and is tested against this 
> > >> patchset:
> > >> 
> > >> https://github.com/rust-vmm/vhost-device/pull/76
> > >
> > >
> > > I'm reluctant to add this with no tests in tree.
> > > Want to write a minimal libhost-user based backend?
> 
> I actually have one already, that I wrote before attempting the Rust
> counterpart, but never upstreamed as I am not sure if anyone is ever
> going to use it, as I am not. And I thought what's the point of
> merging code which I will never end up using.
> 
> I am not sure what test I can add here to make sure this doesn't
> breaks in future though.

something that executes with make check.


> > This is going to be a problem going forward as we have more out-of-tree
> > backends written as a first preference. While the first couple of vhost
> > devices have C implementations in contrib before we worked on the rust
> > version I think we are getting to the point of skipping a first C
> > version for future devices.
> > 
> > However I notice we have qtest/vhost-user-test.c so would that be enough
> > to ensure we can instantiate the device and a basic vhost-user
> > initialisation sequence doesn't cause it to crap out. This obviously
> > won't be exercising the virtq processing itself but does that really
> > exercise any of QEMU's boilerplate anyway?
> > 
> > > We also need some maintainers to step up.
> > 
> > You mean more reviewers for the vhost and virtio sections of QEMU's
> > maintainers?
> 
> And I too was waiting for replies on these. I can surely write
> something up if you guys feel there is a need. I just want to
> understand it better.
> 
> -- 
> viresh