RadeonSI Driver Now Supports AMD Trusted Memory Zone

With the AMDGPU kernel driver adding Trusted Memory Zone support for the Linux 5.8 kernel, Mesa 20.2-devel has now landed support for the RadeonSI driver to make use of this TMZ functionality.

The AMD Trusted Memory Zone support allows for protecting pages from being read by the CPU and other non-GPU clients can protect against writes to those protected pages.

With Linux 5.8 the feature needs to be flipped on via the amdgpu.tmz=1 kernel module parameter but even beyond that the user-space clients need to opt-in for utilizing Trusted Memory Zone.

AMD's Pierre-Eric Pelloux-Prayer has been working on the TMZ support for RadeonSI Gallium3D and that was merged overnight. Besides needing Linux 5.8+, the latest libdrm library is also required.

With the merged code when running on a supported kernel, if setting the AMD_DEBUG=tmz environment variable will enable the Trusted Memory Zone support during OpenGL rendering. So far there isn't any TMZ support for Vulkan or other AMD user-space components.