Why implement the SAU in the PE if you have an IDAU and multiple masters with the same IDAU as the PE?
If the PE has an SAU, the PE will have a different security view of the system then the other masters.
Is this not an issue?
Then why don't use only SAU, since SAU is more flexible? Is this because the SAU has a limited region number? Or because use SAU with IDAU is fast than just usinig SAU?