Any one of the following events results in the generation of a Page Fault exception:
The selected PDE's P bit = 0, indicating that the selected Page Table is not present in memory.
The selected PTE's P bit = 0, indicating that the target page is not present in memory.
An attempt to write to a read-only page.
Insufficient page-level privilege to access the Page Table or the page.
A reserved bit set to one in the PDE or PTE.
If the Page Fault occurs due to a page not present or a page privilege access violation (insufficient privilege or writes are not permitted), the A and D bits are affected in the PDE, but not in the PTE. The PTE's A and D bits are only affected if the page access succeeds.