This is over one year old and mitigations are already out there.
https://www.theregister.co.uk/2017/03/07/eggheads_slip_a_note_under_intels_door_sgx_can_leak_crypto_keys/
https://www.usenix.org/system/files/conference/usenixsecurity17/sec17-gruss.pdf
https://arxiv.org/pdf/1709.09917.pdf
This is a different attack, though.