We would like to understand if this is a customer specific hardware or AMD referance board? The page 74 in http://developer.amd.com/assets/43366_sb7xx_bdg_pub_1.00.pdf talks about how we can utilize SMI to do the thermal monitoring.
So to be clear, it has nothing to do with SMBUS. Instead, to enable Thermal monitoring through SMI, the above document provides example on how GP47 pin of Super IO ITE8712 can be utilized for this purpose.
So check it about a specific implemenation details, the respective platform schematics should be referred. So in case it is AMD Customer referance board, we can provide some help by looking at schematics..