In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu/gfx6: Use PFP on the compute queues too
On GFX6, the compute rings use the same CP path as
the graphics ring. The only difference is that they
don't support draw commands. (As opposed to GFX7 and
newer which have a separate command parser that is
called MEC for compute queues.)
This means that we have to take into consideration
that the PFP also exists on compute queues on GFX6:
Use PFP for register writes on both graphics and
compute queues.
In the pipeline sync, use the PFP to wait for the
previous fence (and not the ME) to prevent the PFP
from starting to execute the next submission while
the ME is still in the previous submission.
After a VM flush, emit PFP_SYNC_ME on compute
queues as well.