Why we didn't use embedded gem object for virtio gpu when making ttm bo a gem bo subclass?

[Gerd Hoffmann]

On Fri, Aug 13, 2021 at 12:42:51PM -0700, lepton wrote:
> Hi Gerd,
> 
> We found a bug in 5.4 kernel and virtgpu_gem_prime_mmap doesn't work
> because it references vma_node in gem_base object while ttm code
> initialized vma_node in tbo.base object. I am wondering, in your
> original serial:
> https://patchwork.kernel.org/project/dri-devel/cover/20190805124310.3275-1-kraxel@redhat.com/
> (drm/ttm: make ttm bo a gem bo subclass), why you changed to use
> embedded gem object for most gpu drivers but skipping virtio gpu? Is
> there some specific reason?

commit c66df701e783bc666593e6e665f13670760883ee
Author: Gerd Hoffmann <kraxel at redhat.com>
Date:   Thu Aug 29 12:32:57 2019 +0200

    drm/virtio: switch from ttm to gem shmem helpers

HTH,
  Gerd