title: TLB flush and page global bit
body: <p>In Intel page table structure, there is "page global" bit which indicates
  the page table entry is globally used.
  In my understanding, this global entry will not be flushed 
  during TLB flushing caused by overwriting CR3.
  my question is, can we assume that global PTE entry will never be flushed from TLB once it is set?</p>