On small-bar systems we could be given something non-mappable here,
which leads to nasty oops. Make this nicer by checking if the resource
is mappable or not, and return an error otherwise.

v2: drop GEM_BUG_ON(flags & I915_BO_ALLOC_GPU_ONLY)

Signed-off-by: Matthew Auld <[email protected]>
Cc: Jianshui Yu <[email protected]>
Cc: Ville Syrjälä <[email protected]>
Cc: Nirmoy Das <[email protected]>
Reviewed-by: Nirmoy Das <[email protected]>
---
 drivers/gpu/drm/i915/gem/i915_gem_object.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c 
b/drivers/gpu/drm/i915/gem/i915_gem_object.c
index 369006c5317f..62495d5d0038 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c
@@ -444,6 +444,16 @@ i915_gem_object_read_from_page_iomap(struct 
drm_i915_gem_object *obj, u64 offset
        io_mapping_unmap(src_map);
 }
 
+static bool object_has_mappable_iomem(struct drm_i915_gem_object *obj)
+{
+       GEM_BUG_ON(!i915_gem_object_has_iomem(obj));
+
+       if (IS_DGFX(to_i915(obj->base.dev)))
+               return 
i915_ttm_resource_mappable(i915_gem_to_ttm(obj)->resource);
+
+       return true;
+}
+
 /**
  * i915_gem_object_read_from_page - read data from the page of a GEM object
  * @obj: GEM object to read from
@@ -466,7 +476,7 @@ int i915_gem_object_read_from_page(struct 
drm_i915_gem_object *obj, u64 offset,
 
        if (i915_gem_object_has_struct_page(obj))
                i915_gem_object_read_from_page_kmap(obj, offset, dst, size);
-       else if (i915_gem_object_has_iomem(obj))
+       else if (i915_gem_object_has_iomem(obj) && 
object_has_mappable_iomem(obj))
                i915_gem_object_read_from_page_iomap(obj, offset, dst, size);
        else
                return -ENODEV;
-- 
2.37.3

Reply via email to