[PATCH] drm/virtio: Allow importing prime buffers when 3D is enabled

[Val Packett <val@invisiblethingslab.com>]

This functionality was added for using a KMS-only virtgpu with a physical
(or SR-IOV) headless GPU in passthrough, but it should not be restricted
to KMS-only mode. It can be used with cross-domain to pass guest memfds
to the host compositor with zero copies (using udmabuf on both sides).

Drop the check for the absence of virgl_3d to allow for more use cases.

Fixes: ca77f27a2665 ("drm/virtio: Import prime buffers from other devices as guest blobs")
Signed-off-by: Val Packett <val@invisiblethingslab.com>
---

Hi. I couldn't find any comments on that line in the reviews (on patchwork), so I assume
there was never a specific technical reason for that check, just an abundance of caution?

BTW, while here.. The drm_gem_prime_import "fallback" seems pretty much equivalent to
`return (-ENODEV)`, as drm_gem_prime_import(_dev) just translates the call to
gem_prime_import_sg_table which we don't use. Should it be replaced with `return (-ENODEV)`?

---
 drivers/gpu/drm/virtio/virtgpu_prime.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_prime.c b/drivers/gpu/drm/virtio/virtgpu_prime.c
index ce49282198cb..2fedd5d3bd62 100644
--- a/drivers/gpu/drm/virtio/virtgpu_prime.c
+++ b/drivers/gpu/drm/virtio/virtgpu_prime.c
@@ -312,7 +312,7 @@ struct drm_gem_object *virtgpu_gem_prime_import(struct drm_device *dev,
 		}
 	}
 
-	if (!vgdev->has_resource_blob || vgdev->has_virgl_3d)
+	if (!vgdev->has_resource_blob)
 		return drm_gem_prime_import(dev, buf);
 
 	bo = kzalloc(sizeof(*bo), GFP_KERNEL);
-- 
2.51.2