[Intel-gfx] RFC: Unpinned DMA-buf handling

[Christian König]

Hi everyone,

hopefully the last iteration of those patches.

For now I've addressed the issue of unmapping imported BOs from the amdgpu page tables immediately by locking the page tables in place.

For HMM handling we are getting the ability to invalidate BOs without locking the VM anyway, so this last TODO will probably go away rather soon.

Place comment,
Christian.