seems ttm_bo_handle_move_mem not flush cache, if BO move SYS->VRAM?

[april]

hi all:

I have a question:

If a BO in VRAM (WC) evict to SYS memory(may be cached),  and user
process still can access it event it is in SYS memory (may be cached)
.
when this BO volidate to VRAM,  It seems "ttm_bo_handle_move_mem"  not
flush cache (If evict to SYS memory with cached).

 But flush cache is needed, If driver use DMA to handle BO
move(SYS->VRAM), should "ttm_bo_handle_move_mem" handle this? or
driver do it in "driver->move_notify" before "driver->move" called?

Thanks