WIP: Add virtio-gpu backend to OpenglSystem.
This change switches device OpenGL emulation over to using virtio-gpu
instead of qemu pipes. The feature is enabled at compile time, and only
if BOARD_GPU_DRIVERS contains "virgl", which is used by other projects
to trigger support for virtio-gpu 3d.
Control stream writes are passed through the existing virtio-gpu 3d
ioctls, and they can be processed in batches, so long as no response is
required. Because responses cannot be sent from kernel->usermode in the
same way socket data can, a "response page" is configured, which is
written to by a qemu driver.
Bug: 77276633
Test: foo
Change-Id: I7ee8b6db815b35d708630dda417039b80d2dfddf
9 files changed