A page fault occurs when a page is referenced which is not currently loaded in memory.

If VPN had been 07 and set 3, we would have had a TLB miss.

The page table entry for VPN 07 would have to be fetched from memory.

But that page table entry is

      VPN  PPN  Valid
      07    -     0
   

The page is NOT in memory. So the MMU hardware generates a page fault.

The operating system page fault handler then must fetch the page from disk! (~100,000 times slower)

Then the Page Table must be updated and the entry changed to valid.

The TLB cache is also updated.

Then what?