[PATCH 1/2] drm/msm: Disallow foreign mapping of _NO_SHARE

[Rob Clark]

This restriction applies to mapping of _NO_SHARE objs in the kms vm as
well as importing/exporting BOs.  Since the DPU has it's own VM, scanout
counts as "exporting" a BO from outside of it's host VM.

Signed-off-by: Rob Clark <robin.clark@xxxxxxxxxxxxxxxx>
---
v2: Fix issue with MAP_NULL

 drivers/gpu/drm/msm/msm_gem_vma.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/msm/msm_gem_vma.c b/drivers/gpu/drm/msm/msm_gem_vma.c
index 1c6b0920c0d8..43d61e0919bd 100644
--- a/drivers/gpu/drm/msm/msm_gem_vma.c
+++ b/drivers/gpu/drm/msm/msm_gem_vma.c
@@ -373,6 +373,12 @@ msm_gem_vma_new(struct drm_gpuvm *gpuvm, struct drm_gem_object *obj,
 	struct msm_gem_vma *vma;
 	int ret;
 
+	/* _NO_SHARE objs cannot be mapped outside of their "host" vm: */
+	if (obj && (to_msm_bo(obj)->flags & MSM_BO_NO_SHARE) &&
+	    GEM_WARN_ON(obj->resv != drm_gpuvm_resv(gpuvm))) {
+		return ERR_PTR(-EINVAL);
+	}
+
 	drm_gpuvm_resv_assert_held(&vm->base);
 
 	vma = kzalloc(sizeof(*vma), GFP_KERNEL);
-- 
2.53.0