The guest memory is allocated through hugetlb. Huge page fault is
triggered by writing a byte to the starting address for each huge page.
In hugetlb_fault(), The physical pages are allocated and *clear*.
So no need to erasing the memory again after hugetlb setup. This will
bring about 130ms (changes with platform) latency for each 1G memory.
Notice: this means we depends on kernel to erase the memory in huge page
fault!
Tracked-On: #7298
Signed-off-by: Conghui <conghui.chen@intel.com>
Acked-by: Wang, Yu1 <yu1.wang@intel.com>