[Qemu-devel] tcg: How CPUState::current_tb is used?

[Sergey Fedorov]

Hi,

I can't figure out how this field is used. The comment says it's
"Currently executing TB", but actually it's the first TB in a chain of
TBs executed. Grep shows the only place it is really checked is
tb_invalidate_phys_page_range(). That code seems to be introduced long
ago in:

    commit ea1c18022edd0e2c45552d6fc2da6e15a3486b33
    Author: bellard <bellard@c046a42c-6fe2-441c-8c8c-71466251a162>
    Date:   Mon Jun 14 18:56:36 2004 +0000

        fixed self modifying code in case of asynchronous interrupt


I suspect it's only related to user emulation. But I would appreciate if
someone could give me an idea of how this really works :)

Thanks,
Sergey