From: Rob Clark robdclark@chromium.org

virtgpu "vram" GEM objects do not implement obj->get_sg_table(). But they also don't use drm_gem_map_dma_buf(). In fact they may not even have guest visible pages. But it is perfectly fine to export and share with other virtual devices.

Reported-by: Dominik Behr dbehr@chromium.org Fixes: 207395da5a97 ("drm/prime: reject DMA-BUF attach when get_sg_table is missing") Signed-off-by: Rob Clark robdclark@chromium.org --- drivers/gpu/drm/drm_prime.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 7352bde299d5..64dd6276e828 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -582,7 +582,12 @@ int drm_gem_map_attach(struct dma_buf *dma_buf, { struct drm_gem_object *obj = dma_buf->priv;

- if (!obj->funcs->get_sg_table) + /* + * drm_gem_map_dma_buf() requires obj->get_sg_table(), but drivers + * that implement their own ->map_dma_buf() do not. + */ + if ((dma_buf->ops->map_dma_buf == drm_gem_map_dma_buf) && + !obj->funcs->get_sg_table) return -ENOSYS;

return drm_gem_pin(obj);