| Message ID | 20210312172821.31647-9-alex.bennee@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | plugins/next (phys addr, syscalls, lots of docs) | expand |
On Mar 12 17:28, Alex Bennée wrote: > Also add a note to explain currently they are unused. > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> I'm personally interested in one clarification below, but don't think that affects my: Reviewed-by: Aaron Lindsay <aaron@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? -Aaron
Aaron Lindsay <aaron@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.bennee@linaro.org> > > I'm personally interested in one clarification below, but don't think > that affects my: > > Reviewed-by: Aaron Lindsay <aaron@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. > > -Aaron -- Alex Bennée
On Mar 16 13:40, Alex Bennée wrote: > > Aaron Lindsay <aaron@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.bennee@linaro.org> > > > > I'm personally interested in one clarification below, but don't think > > that affects my: > > > > Reviewed-by: Aaron Lindsay <aaron@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
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. + */ enum qemu_plugin_cb_flags { - 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 */ + QEMU_PLUGIN_CB_NO_REGS, + QEMU_PLUGIN_CB_R_REGS, + QEMU_PLUGIN_CB_RW_REGS, }; enum qemu_plugin_mem_rw {
Also add a note to explain currently they are unused. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> --- include/qemu/qemu-plugin.h | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) -- 2.20.1