Each XMPU uses the inbound SMID in each AXI transaction to validate the transfer. The SMID is masked by the [MASK] bit field and then compared against the [ID] bit field of the Rxx_SMID region registers (example, R00_SMID ).
If the following equation is satisfied (along with security and read/write checks), the transaction is allowed. In this equation, these are [10-bit parameters] in the Rxx_SMID register
[ID] & [MASK] == AXI_SMID & [MASK]