Re: [virtio-dev] [RFC] Upstreaming virtio-wayland (or an alternative)

[David Stevens <stevensd@chromium.org>]

On Fri, Feb 28, 2020 at 7:30 PM Gerd Hoffmann <kraxel@redhat.com> wrote:
>
> On Fri, Feb 28, 2020 at 07:11:40PM +0900, David Stevens wrote:
> > > But there also is "unix socket", or maybe a somewhat broader "stream",
> > > which would be another feature flag I guess because virtio-ipc would
> > > just tunnel the stream without the help from other devices.
> >
> > Can you elaborate on what you mean by this? I can envision how
> > virtio-ipc would be a generic mechanism for passing data+virtio
> > resources, including any new types of resources it itself defines.
> > However, if "unix sockets" or a generic "stream" expands beyond
> > virtio, that seems too broad, with too many edge cases to be feasible
> > to implement.
>
> As far I know this is exactly what virtio-wayland does today if you try
> to pass a unix socket file descriptor to the other side, so I assume
> this functionality is needed ...

As Zach said earlier, virtio-wayland implements just enough FD sharing
support to get wayland working. However, there are many other
situations where virtio-wayland's unix socket support isn't
sufficient. I think adding support for sharing unix sockets to a
generic virtio-ipc would imply that the support is more comprehensive
than would be feasible to implement. So while virtio-ipc should
support wayland, either directly or with the support of
userspace/another virtio device, it also shouldn't overpromise what it
is capable of doing.

-David