[PATCH 3/3] drm/amdgpu: more descriptive message if HMM not enabled

[Michel Dänzer]

On 2019-03-05 7:09 p.m., Yang, Philip wrote:
> If using old kernel config file, CONFIG_ZONE_DEVICE is not selected,
> so CONFIG_HMM and CONFIG_HMM_MIRROR is not enabled, the current driver
> error message "Failed to register MMU notifier" is not clear. Inform
> user with more descriptive message on how to fix the missing kernel
> config option.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109808
> 
> Change-Id: Idfebaeababa4c37c1ef093c2b91a26910a167585
> Signed-off-by: Philip Yang <Philip.Yang at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
> index 4803e216e174..b155cac52aca 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
> @@ -53,6 +53,8 @@ static inline struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev,
>  }
>  static inline int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr)
>  {
> +	DRM_ERROR("HMM_MIRROR kernel config option is not enabled\n");
> +	DRM_ERROR("add CONFIG_ZONE_DEVICE=y in config file to fix this\n");
>  	return -ENODEV;
>  }
>  static inline void amdgpu_mn_unregister(struct amdgpu_bo *bo) {}
> 

amdgpu_gem_userptr_ioctl calls amdgpu_mn_register if userspace sets the
AMDGPU_GEM_USERPTR_REGISTER flag, so buggy/malicious userspace could
spam dmesg with these errors. I'm afraid a different solution is needed.


-- 
Earthling Michel Dänzer               |              https://www.amd.com
Libre software enthusiast             |             Mesa and X developer