| Message ID | 20230417164041.684562-11-peter.maydell@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | Deprecate/rename singlestep command line option, monitor interfaces | expand |
On 17/4/23 18:40, Peter Maydell wrote: > The 'singlestep' member of StatusInfo has never done what the QMP > documentation claims it does. What it actually reports is whether > TCG is working in "one guest instruction per translation block" mode. > > We no longer need this field for the HMP 'info status' command, as > we've moved that information to 'info jit'. It seems unlikely that > anybody is monitoring the state of this obscure TCG setting via QMP, > especially since QMP provides no means for changing the setting. So > simply deprecate the field, without providing any replacement. > > Until we do eventually delete the member, correct the misstatements > in the QAPI documentation about it. > > If we do find that there are users for this, then the most likely way > we would provide replacement access to the information would be to > put the accelerator QOM object at a well-known path such as > /machine/accel, which could then be used with the existing qom-set > and qom-get commands. > > Signed-off-by: Peter Maydell <peter.maydell@linaro.org> > --- > For v3: because we're only deprecating the existing member, > not trying to provide a replacement with a new name, we don't > need to update the iotests that use the command. (We will when > we eventually drop the deprecated member.) > --- > docs/about/deprecated.rst | 14 ++++++++++++++ > qapi/run-state.json | 14 +++++++++++--- > 2 files changed, 25 insertions(+), 3 deletions(-) Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Markus -- could I trouble you for a quick review of this patch? It's the only one in the series that touches QMP. Everything else has been reviewed so otherwise this series is ready to go in. thanks -- PMM On Mon, 17 Apr 2023 at 17:40, Peter Maydell <peter.maydell@linaro.org> wrote: > > The 'singlestep' member of StatusInfo has never done what the QMP > documentation claims it does. What it actually reports is whether > TCG is working in "one guest instruction per translation block" mode. > > We no longer need this field for the HMP 'info status' command, as > we've moved that information to 'info jit'. It seems unlikely that > anybody is monitoring the state of this obscure TCG setting via QMP, > especially since QMP provides no means for changing the setting. So > simply deprecate the field, without providing any replacement. > > Until we do eventually delete the member, correct the misstatements > in the QAPI documentation about it. > > If we do find that there are users for this, then the most likely way > we would provide replacement access to the information would be to > put the accelerator QOM object at a well-known path such as > /machine/accel, which could then be used with the existing qom-set > and qom-get commands. > > Signed-off-by: Peter Maydell <peter.maydell@linaro.org> > --- > For v3: because we're only deprecating the existing member, > not trying to provide a replacement with a new name, we don't > need to update the iotests that use the command. (We will when > we eventually drop the deprecated member.) > --- > docs/about/deprecated.rst | 14 ++++++++++++++ > qapi/run-state.json | 14 +++++++++++--- > 2 files changed, 25 insertions(+), 3 deletions(-) > > diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst > index 6f5e689aa45..d5eda0f566c 100644 > --- a/docs/about/deprecated.rst > +++ b/docs/about/deprecated.rst > @@ -199,6 +199,20 @@ accepted incorrect commands will return an error. Users should make sure that > all arguments passed to ``device_add`` are consistent with the documented > property types. > > +``StatusInfo`` member ``singlestep`` (since 8.1) > +'''''''''''''''''''''''''''''''''''''''''''''''' > + > +The ``singlestep`` member of the ``StatusInfo`` returned from the > +``query-status`` command is deprecated. This member has a confusing > +name and it never did what the documentation claimed or what its name > +suggests. We do not believe that anybody is actually using the > +information provided in this member. > + > +The information it reports is whether the TCG JIT is in "one > +instruction per translated block" mode (which can be set on the > +command line or via the HMP, but not via QMP). The information remains > +available via the HMP 'info jit' command. > + > Human Monitor Protocol (HMP) commands > ------------------------------------- > > diff --git a/qapi/run-state.json b/qapi/run-state.json > index 9d34afa39e0..daf03a6fe9c 100644 > --- a/qapi/run-state.json > +++ b/qapi/run-state.json > @@ -104,16 +104,24 @@ > # > # @running: true if all VCPUs are runnable, false if not runnable > # > -# @singlestep: true if VCPUs are in single-step mode > +# @singlestep: true if using TCG with one guest instruction > +# per translation block > # > # @status: the virtual machine @RunState > # > +# Features: > +# @deprecated: Member 'singlestep' is deprecated (with no replacement). > +# > # Since: 0.14 > # > -# Notes: @singlestep is enabled through the GDB stub > +# Notes: @singlestep is enabled on the command line with > +# '-accel tcg,one-insn-per-tb=on', or with the HMP > +# 'one-insn-per-tb' command. > ## > { 'struct': 'StatusInfo', > - 'data': {'running': 'bool', 'singlestep': 'bool', 'status': 'RunState'} } > + 'data': {'running': 'bool', > + 'singlestep': { 'type': 'bool', 'features': [ 'deprecated' ]}, > + 'status': 'RunState'} } > > ## > # @query-status: > -- > 2.34.1
On Tue, 25 Apr 2023 at 13:10, Markus Armbruster <armbru@redhat.com> wrote: > > Peter Maydell <peter.maydell@linaro.org> writes: > > > -# Notes: @singlestep is enabled through the GDB stub > > +# Notes: @singlestep is enabled on the command line with > > +# '-accel tcg,one-insn-per-tb=on', or with the HMP > > +# 'one-insn-per-tb' command. > > You're deleting "enabled through the GDB stub". Is this one of the > misstatements you alluded to in the commit message Yes -- this field has never been anything to do with GDB-enabled singlestep (or for that matter with emulation of any guest-CPU architecture singlestep functionality). I assume that whoever originally wrote that text was confused by the terrible name of the command line option/global variable. -- PMM
Peter Maydell <peter.maydell@linaro.org> writes: > On Tue, 25 Apr 2023 at 13:10, Markus Armbruster <armbru@redhat.com> wrote: >> >> Peter Maydell <peter.maydell@linaro.org> writes: >> >> > -# Notes: @singlestep is enabled through the GDB stub >> > +# Notes: @singlestep is enabled on the command line with >> > +# '-accel tcg,one-insn-per-tb=on', or with the HMP >> > +# 'one-insn-per-tb' command. >> >> You're deleting "enabled through the GDB stub". Is this one of the >> misstatements you alluded to in the commit message > > Yes -- this field has never been anything to do with > GDB-enabled singlestep (or for that matter with > emulation of any guest-CPU architecture singlestep > functionality). I assume that whoever originally wrote > that text was confused by the terrible name of the > command line option/global variable. Thanks! Reviewed-by: Markus Armbruster <armbru@redhat.com>
diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index 6f5e689aa45..d5eda0f566c 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -199,6 +199,20 @@ accepted incorrect commands will return an error. Users should make sure that all arguments passed to ``device_add`` are consistent with the documented property types. +``StatusInfo`` member ``singlestep`` (since 8.1) +'''''''''''''''''''''''''''''''''''''''''''''''' + +The ``singlestep`` member of the ``StatusInfo`` returned from the +``query-status`` command is deprecated. This member has a confusing +name and it never did what the documentation claimed or what its name +suggests. We do not believe that anybody is actually using the +information provided in this member. + +The information it reports is whether the TCG JIT is in "one +instruction per translated block" mode (which can be set on the +command line or via the HMP, but not via QMP). The information remains +available via the HMP 'info jit' command. + Human Monitor Protocol (HMP) commands ------------------------------------- diff --git a/qapi/run-state.json b/qapi/run-state.json index 9d34afa39e0..daf03a6fe9c 100644 --- a/qapi/run-state.json +++ b/qapi/run-state.json @@ -104,16 +104,24 @@ # # @running: true if all VCPUs are runnable, false if not runnable # -# @singlestep: true if VCPUs are in single-step mode +# @singlestep: true if using TCG with one guest instruction +# per translation block # # @status: the virtual machine @RunState # +# Features: +# @deprecated: Member 'singlestep' is deprecated (with no replacement). +# # Since: 0.14 # -# Notes: @singlestep is enabled through the GDB stub +# Notes: @singlestep is enabled on the command line with +# '-accel tcg,one-insn-per-tb=on', or with the HMP +# 'one-insn-per-tb' command. ## { 'struct': 'StatusInfo', - 'data': {'running': 'bool', 'singlestep': 'bool', 'status': 'RunState'} } + 'data': {'running': 'bool', + 'singlestep': { 'type': 'bool', 'features': [ 'deprecated' ]}, + 'status': 'RunState'} } ## # @query-status:
The 'singlestep' member of StatusInfo has never done what the QMP documentation claims it does. What it actually reports is whether TCG is working in "one guest instruction per translation block" mode. We no longer need this field for the HMP 'info status' command, as we've moved that information to 'info jit'. It seems unlikely that anybody is monitoring the state of this obscure TCG setting via QMP, especially since QMP provides no means for changing the setting. So simply deprecate the field, without providing any replacement. Until we do eventually delete the member, correct the misstatements in the QAPI documentation about it. If we do find that there are users for this, then the most likely way we would provide replacement access to the information would be to put the accelerator QOM object at a well-known path such as /machine/accel, which could then be used with the existing qom-set and qom-get commands. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- For v3: because we're only deprecating the existing member, not trying to provide a replacement with a new name, we don't need to update the iotests that use the command. (We will when we eventually drop the deprecated member.) --- docs/about/deprecated.rst | 14 ++++++++++++++ qapi/run-state.json | 14 +++++++++++--- 2 files changed, 25 insertions(+), 3 deletions(-)