On Mon, Mar 21, 2022 at 12:10:43PM +0000, Thomas Leonard wrote:
> Looking at the Linux virtio_gpu driver, it seems that using contexts
> requires virgl:
>
> static int virtio_gpu_context_init_ioctl(struct drm_device *dev, void
> *data, struct drm_file *file)
> {
>   ...
>   if (!vgdev->has_context_init || !vgdev->has_virgl_3d)
>     return -EINVAL;
>
> https://github.com/torvalds/linux/blob/f443e374ae131c168a065ea1748feac6b2e76613/drivers/gpu/drm/virtio/virtgpu_ioctl.c#L732
>
> I think perhaps that crosvm is compiled without the "virgl_renderer"
> feature (it's not in the default set), and this is causing it to crash
> because that's also "self.default_component". I don't know how to
> compile crosvm with virgl enabled, though.

It wasn't easy, but I got it to build[1].  I hope that helps.  It adds
both virgl_renderer and virgl_renderer_next.  I think virgl_renderer
is on by default with --gpu, and virgl_renderer_next is used with the
--gpu-render-server argument.  Hopefully at least one of those does the
right thing — let me know!

[1]: https://github.com/NixOS/nixpkgs/pull/165128