Re: [PATCH-for-11.0?] target/i386: Mandate monitor 'info lapic' take a vCPU ID argument

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Apr 13, 2026 at 03:07:48PM +0200, Philippe Mathieu-Daudé wrote:
> With SMP configurations, using the 'current vCPU' under the
> monitor isn't recommended, as it changes during runtime. Better
> to specify which vCPU we want to monitor by its index. Deprecate
> the default of 'info lapic', mentioning an argument is expected,
> so we can remove this unpredictable behavior one day.
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
> The other command with this unpredictable behavior is 'info tlb'
> which we'll deal with differently, after the v11.0 release.

Aren't there quite a few more commands that rely on the HMP
"current" vCPU concept besides these two ?

info registers  comes to mind, 

There are others whic call mon_get_cpu(), which are not
directly caring about a specific CPU, eg 'info mem',
'memory_dump'

Why the rush to get lapic deprecated in 11.0 but not the
otherrs ?


> ---
>  docs/about/deprecated.rst | 6 ++++++
>  target/i386/cpu-apic.c    | 2 ++
>  hmp-commands-info.hx      | 3 +--
>  3 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
> index a6d6a713265..a62da93259a 100644
> --- a/docs/about/deprecated.rst
> +++ b/docs/about/deprecated.rst
> @@ -169,6 +169,12 @@ The ``stopcapture`` command is deprecated and will be removed in a future releas
>  
>  The ``info capture`` command is deprecated and will be removed in a future release.
>  
> +``info lapic`` without ``apic-id`` argument (since 11.0)
> +''''''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +When no APIC ID is provided, ``info lapic`` defaults to the current vCPU.
> +This behavior is now deprecated, the ID will be mandatory in a future release.
> +
>  Host Architectures
>  ------------------
>  
> diff --git a/target/i386/cpu-apic.c b/target/i386/cpu-apic.c
> index eaa10ad2a3d..9ca569f62b8 100644
> --- a/target/i386/cpu-apic.c
> +++ b/target/i386/cpu-apic.c
> @@ -97,6 +97,8 @@ void hmp_info_local_apic(Monitor *mon, const QDict *qdict)
>              cpu_synchronize_state(cs);
>          }
>      } else {
> +        monitor_printf(mon, "Not specifying the local apic id is deprecated"
> +                       " (using the current CPU one)\n");
>          cs = mon_get_cpu(mon);
>      }
>  
> diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
> index 74c741f80e2..e4206d329fc 100644
> --- a/hmp-commands-info.hx
> +++ b/hmp-commands-info.hx
> @@ -118,8 +118,7 @@ ERST
>          .name       = "lapic",
>          .args_type  = "apic-id:i?",
>          .params     = "[apic-id]",
> -        .help       = "show local apic state (apic-id: local apic to read, default is which of current CPU)",
> -
> +        .help       = "show local apic state (apic-id: local apic to read)",
>          .cmd        = hmp_info_local_apic,
>      },
>  #endif
> -- 
> 2.53.0
> 

With regards,
Daniel
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