In SQL Server 2012 RTM/SP1, Power View can consume data from tabular models, however multidimensional models (a.k.a. “cubes”) were not supported. The Power View for Multidimensional Models CTP addresses this key limitation. Now Power View users can connect to both tabular BI Semantic Model AND multidimensional BI Semantic Model (cubes). This is achieved through native support for Data Analysis Expressions (DAX) in Analysis Services Multidimensional models, ensuring optimal performance and functionality.
The SQL Server BI team blogged about it here. You can also directly download the Microsoft SQL Server 2012 With Power View For Multidimensional Models CTP.