On Fri, Apr 21, 2023 at 9:02 AM Stefan Hajnoczi <stefa...@gmail.com> wrote: > > On Thu, 20 Apr 2023 at 21:13, Gurchetan Singh > <gurchetansi...@chromium.org> wrote: > > > > From: Gurchetan Singh <gurchetansi...@google.com> > > > > Rationale: > > > > - gfxstream [a] is good for the Android Emulator/upstream QEMU > > alignment > > - Wayland passhthrough [b] via the cross-domain context type is good > > for Linux on Linux display virtualization > > - rutabaga_gfx [c] sits on top of gfxstream, cross-domain and even > > virglrenderer > > - This series ports rutabaga_gfx to QEMU > > What rutabaga_gfx and gfxstream? Can you explain where they sit in the > stack and how they build on or complement virtio-gpu and > virglrenderer?
rutabaga_gfx and gfxstream are both libraries that implement the virtio-gpu protocol. There's a document available in the Gitlab issue to see where they fit in the stack [a]. gfxstream grew out of the Android Emulator's need to virtualize graphics for app developers. There's a short history of gfxstream in patch 10. It complements virglrenderer in that it's a bit more cross-platform and targets different use cases -- more detail here [b]. The ultimate goal is ditch out-of-tree kernel drivers in the Android Emulator and adopt virtio, and porting gfxstream to QEMU would speed up that transition. rutabaga_gfx is a much smaller Rust library that sits on top of gfxstream and even virglrenderer, but does a few extra things. It implements the cross-domain context type, which provides Wayland passthrough. This helps virtio-gpu by providing more modern display virtualization. For example, Microsoft for WSL2 also uses a similar technique [c], but I believe it is not virtio-based nor open-source. With this, we can have the same open-source Wayland passthrough solution on crosvm, QEMU and even Fuchsia [d]. Also, there might be an additional small Rust context type for security-sensitive use cases in the future -- rutabaga_gfx wouldn't compile its gfxstream bindings (since it's C++ based) in such cases. Both gfxstream and rutabaga_gfx are a part of the virtio spec [e] now too. [a] https://gitlab.com/qemu-project/qemu/-/issues/1611 [b] https://lists.gnu.org/archive/html/qemu-devel/2023-03/msg04271.html [c] https://www.youtube.com/watch?v=EkNBsBx501Q [d] https://fuchsia-review.googlesource.com/c/fuchsia/+/778764 [e] https://github.com/oasis-tcs/virtio-spec/blob/master/device-types/gpu/description.tex#L533 > > Stefan
