Re: [Qemu-devel] [PATCH v2 1/2] hmp: dump ids including socket-id, core-id and so on for 'info registers'

[Eduardo Habkost <ehabkost@redhat.com>]

On Wed, Jul 26, 2017 at 02:18:36AM -0400, Yi Wang wrote:
> This patch add output of CPUs' socket-id, core-id, thread-id and
> apic-id for 'info registers', which can be used for querying other
> hmp commands.
> 
> Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
> Signed-off-by: Yun Liu <liu.yunh@zte.com.cn>
> ---
>  target/i386/helper.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/target/i386/helper.c b/target/i386/helper.c
> index f63eb3d..a52f300 100644
> --- a/target/i386/helper.c
> +++ b/target/i386/helper.c
> @@ -416,6 +416,14 @@ void x86_cpu_dump_state(CPUState *cs, FILE *f, fprintf_function cpu_fprintf,
>      int eflags, i, nb;
>      char cc_op_name[32];
>      static const char *seg_name[6] = { "ES", "CS", "SS", "DS", "FS", "GS" };
> +    APICCommonState *s = APIC_COMMON(cpu->apic_state);
> +
> +    if (!s) {
> +        cpu_fprintf(f, "local apic state not available\n");
> +        return;
> +    }

This breaks "info registers" on 486:

  $ ./x86_64-softmmu/qemu-system-x86_64 -cpu 486 -display none -monitor stdio
  QEMU 2.9.90 monitor - type 'help' for more information
  (qemu) info registers
  local apic state not available
  (qemu)

You can simply use X86CPU::apic_id.  The field is set to a consistent value
even if there's no guest-visible APIC, because we use it as a VCPU identifier
internally.

However, I'm not sure "info registers" is the right place to print this info.
I think "info cpus" would be a more obvious place, but it would probably make
its output too long.

We could implement something like "info cpus -v", but: the "apic-id" info would
be redundant as soon as we replace "CPU #<cpu_index>" with "CPU #<arch_id>",
and other details like socket/core/thread could just appear on "info qtree".


> +    cpu_fprintf(f, "(socket-id:%d core-id:%d thread-id:%d apic-id:%d)\n",
> +            cpu->socket_id, cpu->core_id, cpu->thread_id, s->id);
>  
>      eflags = cpu_compute_eflags(env);
>  #ifdef TARGET_X86_64
> -- 
> 1.8.3.1
> 
> 

-- 
Eduardo