Does a CPU cache entry contains physical or virtual address?

Question

Does a CPU cache deal with physical or virtual addresses? And if it deals with virtual addresses, does that mean that it has be to emptied on context switch, assuming that the new thread is from another process.

Answer 1

This depends on the processor model. Some processors use both. (See “SPARC” in the “Virtual tags and vhints” section.)

You have tagged this question with x86-64, and an answer could be given for all x86-64 models to date, but I am not sure whether the architecture specification specifies whether processors conforming to the specification must use one or the other for cache information.