PhD funding source for international student in the UK I will start my PhD in computer science at a UK university soon. Even though the university has given me a partial funding, I still need to cover part of my tuition fee and living expenses. My university offers teaching assistant position but its payment is very limited.

I've been looking and seen that most, if not all, of funding sources are only available for UK and EU students. So, I want to ask if there are any sources for international to apply.
Your best bet is probably to check if there are fellowships available for study abroad from your home country. However, depending on where you're from, there may be special programs available. For instance, there are Commonwealth Scholarships available for people living in members of the British Commonwealth.

There are some databases of UK awards for general students: here, for instance, is a list of postgraduate scholarships available to citizens of any country.