On Mon, Nov 13, 2017 at 03:18:46PM +0100, Tomeu Vizoso wrote: > Hi, > > I'm looking at what would be the best way for Wayland clients running in a > VM to communicate with a Wayland compositor in the host. > > The base Wayland protocol is fairly self-contained, with little or no > references to objects outside the client and the server, so it lends itself > very well to virtualization. > > But there's a problem when passing references to pixel buffers around with > FD passing, as SCM_RIGHTS isn't currently implemented in AF_VSOCK. > > The Wayland project is willing to consider adding AF_VSOCK support to the > libwayland libraries alongside existing support for AF_UNIX, both on client > and server. > > Any opinions on whether adding SCM_RIGHTS support to AF_VSOCK is a good > idea? Not going to work. A file handle is a reference to a kernel object which can be pretty much anything (file, socket, timer, memory, ...) and you can't pass that across machine borders. It's not working for AF_INET for the same reason. > Or other options for letting processes in the host to access shmem > buffers allocated within the guest? > > Regarding the mechanics of mapping guest buffers in the host, I was hoping > the approach described below would work: > > http://www.fp7-save.eu/papers/SCALCOM2016.pdf Doesn't look that useful to me on a quick glance. Lets step back and look at the problem you are trying to solve. It seems you want guest wayland applications appear seamless on the host wayland server, correct? How does the wayland rendering workflow look like? As far I know the wayland protocol doesn't include any rendering. Rendering happens client side, into some buffer (one per window), which is then passed to the server for display compositing. Correct? So you basically want pass that buffer from guest to host? What kind of shared memory is used by wayland? sysv shm? gbm buffers / dmabufs? cheers, Gerd
