6.8-stable review patch. If anyone has any objections, please let me know.
------------------
From: Rob Clark <robdclark@xxxxxxxxxxxx>
[ Upstream commit a4ec240f6b7c21cf846d10017c3ce423a0eae92c ]
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@xxxxxxxxxxxx>
Fixes: 207395da5a97 ("drm/prime: reject DMA-BUF attach when get_sg_table is missing")
Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
Reviewed-by: Simon Ser <contact@xxxxxxxxxxx>
Signed-off-by: Simon Ser <contact@xxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20240322214801.319975-1-robdclark@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 7352bde299d54..03bd3c7bd0dc2 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);
--
2.43.0
