diff mbox series

[v1,08/14] plugins: add qemu_plugin_cb_flags to kernel-doc

Message ID 20210312172821.31647-9-alex.bennee@linaro.org
State Superseded
Headers show
Series plugins/next (phys addr, syscalls, lots of docs) | expand

Commit Message

Alex Bennée March 12, 2021, 5:28 p.m. UTC
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

Comments

Xingtao Yao (Fujitsu)" via March 12, 2021, 6:29 p.m. UTC | #1
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
Alex Bennée March 16, 2021, 1:40 p.m. UTC | #2
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
Xingtao Yao (Fujitsu)" via March 16, 2021, 2:05 p.m. UTC | #3
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 mbox series

Patch

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 {