[RFC v2 8/8] drm: tegra: Add gr2d device

[Dave Airlie]

On Tue, Nov 27, 2012 at 9:31 PM, Terje Bergström <tbergstrom at nvidia.com> wrote:
> On 27.11.2012 12:37, Thierry Reding wrote:
>> But in that case it should be made mandatory at first until proper IOMMU
>> support is enabled on Tegra30. Then it can be checked at driver probe
>> time whether or not to enable the extra checks. That way we don't need a
>> special Kconfig option and we still get all the security that we need,
>> right?
>
> I guess it depends on the level of security.
>
> If we want to only protect kernel and user space memory, this would be
> sufficient and no firewall is needed if IOMMU is turned on.
>
> If we want to protect 2D buffers from each other, this is not sufficient.

We  generally aim for the first, to stop the gpu from reading/writing
any memory it hasn't been granted access to,
the second is nice to have though, but really requires a GPU with VM
to implement properly.

Dave.