Hi, [ Cc'ing David Airlie and Marc-André Lureau ] > > 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? > > 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? > > Correct. > > > What kind of shared memory is used by wayland? > > sysv shm? gbm buffers / dmabufs? > > Typically, shared memory for CPU-rendered content, and dmabufs for > GPU-rendered content. Ok. I guess solving this for virtio-gpu (with virgl enabled) is easiest then. Due to opengl rendering being offloaded to the host gpu the guest window content already is in a host gpu buffer. So we "only" need to export that buffer as dmabuf and pass it to the wayland server. That still doesn't look trivial though. qemu must manage the dmabufs, so it must be involved somehow; a direct guest client -> host server wayland connection (alone) will not work. I think we need either a wayland proxy in qemu which rewrites the buffer references, or the host wayland server must talk to both guest client (vsock could work for that) and qemu (for dmabuf management). Or some mixed model, such as a separate wayland proxy server talking to qemu for dmabuf management. I suspect in any case we need a wayland protocol extension for a new buffer type as passing buffer references from guest to host can't use filehandles. cheers, Gerd
