Musannaf Ibn Abi Shaybah

Hazrat Mujahid says that do not perform the Istilam of Hajar Aswad from the right or left side, rather perform its Istilam from the front.

It is narrated by the person who saw Hazrat Mujahid that he kept circling until his face came directly in front of the Black Stone, (then he performed Istilam).