Re: [PATCH v2 07/10] hmp: Add 'one-insn-per-tb' command equivalent to 'singlestep'

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Peter Maydell (peter.maydell@linaro.org) wrote:
> The 'singlestep' HMP command is confusing, because it doesn't
> actually have anything to do with single-stepping the CPU.  What it
> does do is force TCG emulation to put one guest instruction in each
> TB, which can be useful in some situations.
> 
> Create a new HMP command  'one-insn-per-tb', so we can document that
> 'singlestep' is just a deprecated synonym for it, and eventually
> perhaps drop it.
> 
> We aren't obliged to do deprecate-and-drop for HMP commands,
> but it's easy enough to do so, so we do.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  docs/about/deprecated.rst   |  9 +++++++++
>  include/monitor/hmp.h       |  2 +-
>  softmmu/runstate-hmp-cmds.c |  2 +-
>  tests/qtest/test-hmp.c      |  1 +
>  hmp-commands.hx             | 25 +++++++++++++++++++++----
>  5 files changed, 33 insertions(+), 6 deletions(-)
> 
> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
> index 3c62671dac1..6f5e689aa45 100644
> --- a/docs/about/deprecated.rst
> +++ b/docs/about/deprecated.rst
> @@ -199,6 +199,15 @@ 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.
>  
> +Human Monitor Protocol (HMP) commands
> +-------------------------------------
> +
> +``singlestep`` (since 8.1)
> +''''''''''''''''''''''''''
> +
> +The ``singlestep`` command has been replaced by the ``one-insn-per-tb``
> +command, which has the same behaviour but a less misleading name.
> +
>  Host Architectures
>  ------------------
>  
> diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
> index fdb69b7f9ca..13f9a2dedb8 100644
> --- a/include/monitor/hmp.h
> +++ b/include/monitor/hmp.h
> @@ -158,7 +158,7 @@ void hmp_info_vcpu_dirty_limit(Monitor *mon, const QDict *qdict);
>  void hmp_human_readable_text_helper(Monitor *mon,
>                                      HumanReadableText *(*qmp_handler)(Error **));
>  void hmp_info_stats(Monitor *mon, const QDict *qdict);
> -void hmp_singlestep(Monitor *mon, const QDict *qdict);
> +void hmp_one_insn_per_tb(Monitor *mon, const QDict *qdict);
>  void hmp_watchdog_action(Monitor *mon, const QDict *qdict);
>  void hmp_pcie_aer_inject_error(Monitor *mon, const QDict *qdict);
>  void hmp_info_capture(Monitor *mon, const QDict *qdict);
> diff --git a/softmmu/runstate-hmp-cmds.c b/softmmu/runstate-hmp-cmds.c
> index 127521a483a..76d1399ed85 100644
> --- a/softmmu/runstate-hmp-cmds.c
> +++ b/softmmu/runstate-hmp-cmds.c
> @@ -41,7 +41,7 @@ void hmp_info_status(Monitor *mon, const QDict *qdict)
>      qapi_free_StatusInfo(info);
>  }
>  
> -void hmp_singlestep(Monitor *mon, const QDict *qdict)
> +void hmp_one_insn_per_tb(Monitor *mon, const QDict *qdict)
>  {
>      const char *option = qdict_get_try_str(qdict, "option");
>      AccelState *accel = current_accel();
> diff --git a/tests/qtest/test-hmp.c b/tests/qtest/test-hmp.c
> index b4a920df898..cb3530df722 100644
> --- a/tests/qtest/test-hmp.c
> +++ b/tests/qtest/test-hmp.c
> @@ -64,6 +64,7 @@ static const char *hmp_cmds[] = {
>      "screendump /dev/null",
>      "sendkey x",
>      "singlestep on",
> +    "one-insn-per-tb on",

OK, it wouldn't be bad if this list got a bit back into near alphabetic
order.


Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>


>      "wavcapture /dev/null",
>      "stopcapture 0",
>      "sum 0 512",
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index bb85ee1d267..9afbb54a515 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -378,18 +378,35 @@ SRST
>    only *tag* as parameter.
>  ERST
>  
> +    {
> +        .name       = "one-insn-per-tb",
> +        .args_type  = "option:s?",
> +        .params     = "[on|off]",
> +        .help       = "run emulation with one guest instruction per translation block",
> +        .cmd        = hmp_one_insn_per_tb,
> +    },
> +
> +SRST
> +``one-insn-per-tb [off]``
> +  Run the emulation with one guest instruction per translation block.
> +  This slows down emulation a lot, but can be useful in some situations,
> +  such as when trying to analyse the logs produced by the ``-d`` option.
> +  This only has an effect when using TCG, not with KVM or other accelerators.
> +
> +  If called with option off, the emulation returns to normal mode.
> +ERST
> +
>      {
>          .name       = "singlestep",
>          .args_type  = "option:s?",
>          .params     = "[on|off]",
> -        .help       = "run emulation in singlestep mode or switch to normal mode",
> -        .cmd        = hmp_singlestep,
> +        .help       = "deprecated synonym for one-insn-per-tb",
> +        .cmd        = hmp_one_insn_per_tb,
>      },
>  
>  SRST
>  ``singlestep [off]``
> -  Run the emulation in single step mode.
> -  If called with option off, the emulation returns to normal mode.
> +  This is a deprecated synonym for the one-insn-per-tb command.
>  ERST
>  
>      {
> -- 
> 2.34.1
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK