Do I need a visa with round trip flight?

Hi,
I´m portuguese and i´ll go to BJ next August. I bought a round trip flight, Porto- London - PEK and then PEK- Genebre-Porto. However, I´ll gonna stay in there for 2 days and then I bought flight to Bali. Then I will fly to Hong Kong and return to BJ. In this last stop I´ll no go out of the airport.
Thanks