Function alloc_page_aligned_zeroed 

pub fn alloc_page_aligned_zeroed(len: usize) -> Vec<u8> 

Allocate a zero-filled Vec<u8> of len bytes (rounded up to the next page boundary) with PAGE_SIZE-aligned backing storage. Page alignment is what lets the kernel map the buffer directly into a ring-3 PT.

Panics if the allocator returns null (OOM) or the Layout overflows.