Its roughly even towards all the groups 40% White, 40% Asian and middle eastern and rest more spread out.
From own experience halls tend to have more white people, the university overall is probably one of the most diverse. If you have an issue with south-east Asians QMUL is not the university for you.
Like with anywhere the best thing to do is go to an open day and see how it feels. When I went to a ucas open day for my course I knew QM was my first choice.