On 3 July 2015 at 18:02, Jun Koi <junkoi2...@gmail.com> wrote: > I am looking at how the main thread interrupts TCG thread. Inside > cpu-exec.c, in function cpu_tb_exec(), I can see that it executes one TB, > and when this is over, it can check for events from other threads (like main > thread). This is the reason why TCG thread can be interrupted. > > Is my understanding correct? > > If this is true, then what if this TB is running infinitely, and do not > return, or it is in a very long loop? In this case, TCG thread cannot be > interrupted?
Every TB starts with a little bit of generated code that checks the 'tcg_exit_req' flag in the CPUState for the CPU (see the gen_tb_start() function). If some other part of QEMU wants the CPU to stop running guest code and return to the top level loop, it calls cpu_exit() which sets this flag. thanks -- PMM
