HMM mirror CPU page table into a device page table

modulename: hmm.ko

configname: CONFIG_HMM_MIRROR

Linux Kernel Configuration
└─>Memory Management options
└─>HMM mirror CPU page table into a device page table
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Select HMM_MIRROR if you want to mirror range of the CPU page table of a
process into a device page table. Here, mirror means "keep synchronized".
Prerequisites: the device must provide the ability to write-protect its
page tables (at PAGE_SIZE granularity), and must be able to recover from
the resulting potential page faults.