On Wed, Mar 10, 2021 at 02:19:49PM +0000, Thomas Leonard wrote:
> > > I didn’t have time to write and debug C++ code for every missing
> > > Wayland protocol, so I took a short-cut: I wrote my own Wayland library,
> > > ocaml-wayland, and then used that to write my own version of sommelier.
> > > With that, adding support for copying text was fairly easy.
> >
> > Well this is interesting!  I definitely want to learn more about this.
>
> I've put it up here: https://github.com/talex5/wayland-virtwl-proxy
>
> There's a default.nix file, so it should build easily enough (make
> sure to git clone with submodules). I'd be interested to know if it
> works for other people. I've been using it for about a week now, and
> it seems fine with firefox, evince and xfce4-terminal (the apps I
> use).
>
> But e.g. kitty won't run because there's no `wl_drm` support. I don't
> know anything about graphics acceleration. But someone on Hacker News
> commented that you did panfrost, so I guess you know about that sort
> of thing.

Alas, I am not Alyssa Rosenzweig of panfrost (gosh how much easier this
would be if I knew as much about Linux graphics as she does!).  But it
is not uncommon that people get us mixed up. :)

FWIW, wl_drm solves your complaint of having to copy buffers from
client-allocated memory -- with wl_drm, the client is given a dmabuf
from the server.  As I understand it, Chromium OS already supports this
with virtio-gpu, but I haven't tried that yet.

> > > I’m not sure how guest-to-guest communication works with KVM.
> >
> > It... doesn't really, at least not the way it does with Xen.
> > virtio-vhost-user[1] is promising, but very early stages.  I've talked
> > in quite a lot of detail about how that works on this list before as
> > well.  guest-to-guest communication was my main area of work for most of
> > the second half of last year (and what ended up causing me to burn out).
>
> I guess once you've got shared memory and inter-VM interrupts it might
> be possible to reuse the Xen protocols and drivers. I made a firewall
> VM on Qubes that did that a few years ago
> (https://roscidus.com/blog/blog/2016/01/01/a-unikernel-firewall-for-qubesos/).
> But the virtio protocols will probably be more widely supported in
> future.

That's an interesting idea I hadn't considered.  But I am hoping that
virtio gets to the point that we don't need to do that in a reasonable
amount of time.