On Mar 16 13:40, Alex Bennée wrote: > > Aaron Lindsay <aa...@os.amperecomputing.com> writes: > > > On Mar 12 17:28, Alex Bennée wrote: > >> Also add a note to explain currently they are unused. > >> > >> Signed-off-by: Alex Bennée <alex.ben...@linaro.org> > > > > I'm personally interested in one clarification below, but don't think > > that affects my: > > > > Reviewed-by: Aaron Lindsay <aa...@os.amperecomputing.com> > > > >> --- > >> include/qemu/qemu-plugin.h | 16 +++++++++++++--- > >> 1 file changed, 13 insertions(+), 3 deletions(-) > >> > >> diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h > >> index 9ae3940d89..c98866a637 100644 > >> --- a/include/qemu/qemu-plugin.h > >> +++ b/include/qemu/qemu-plugin.h > >> @@ -207,10 +207,20 @@ struct qemu_plugin_tb; > >> /** struct qemu_plugin_insn - Opaque handle for a translated instruction > >> */ > >> struct qemu_plugin_insn; > >> > >> +/** > >> + * enum qemu_plugin_cb_flags - type of callback > >> + * > >> + * @QEMU_PLUGIN_CB_NO_REGS: callback does not access the CPU's regs > >> + * @QEMU_PLUGIN_CB_R_REGS: callback reads the CPU's regs > >> + * @QEMU_PLUGIN_CB_RW_REGS: callback reads and writes the CPU's regs > >> + * > >> + * Note: currently unused, plugins cannot read or change system > >> + * register state. > > > > They are unused in the sense that the current plugin interface does not > > provide a way to make use of them. But are they completely free from > > side effects? > > They are free of side effects visible to the plugin. Under the covers it > uses the existing TCG_CALL_NO_* mechanics to ensure that register state > is synced to/from TCG temporaries before the callback.
I would currently find it useful to have that information included in the documentation since there is no register state exposed and I am basically hacking something together for my own use in the meantime... but I understand that is in tension with the general philosophy of the plugins to not expose implementation details. -Aaron
