Re: [PATCH 1/1] hw/core/cpu: always print cpu index with cpu state

[Dongli Zhang]

Ping?

The patch already got the Reviewed-by from Philippe Mathieu-Daudé and Alistair
Francis.

The current log does not provide much information when (1) multiple CPUs are
involved in the bug, and (2) when the "info registers -a" is not used to collect
the context from all CPUs for comparison.

We may wait for very long timer until the bug filer can reproduce the error 
again.

To print the cpu index helps a lot.

Thank you very much!

Dongli Zhang

On 2/6/23 15:42, Dongli Zhang wrote:
> The cpu_dump_state() does not print the cpu index. When the
> cpu_dump_state() is invoked due to the KVM failure, we are not able to tell
> from which CPU the state is. The below is an example.
> 
> KVM internal error. Suberror: 764064
> RAX=0000000000000002 RBX=ffff8a9e57c38400 RCX=00000000ffffffff 
> RDX=ffff8a9cc00ba8a0
> RSI=0000000000000003 RDI=ffff8a9e57c38400 RBP=ffffb6120c5b3c50 
> RSP=ffffb6120c5b3c40
> R8 =0000000000000000 R9 =ffff8a9cc00ba8a0 R10=ffffffff8e467350 
> R11=0000000000000007
> R12=000000000000000a R13=ffffffff8f987e25 R14=ffffffff8f988a01 
> R15=0000000000000000
> RIP=ffffffff8e51bb04 RFL=00010046 [---Z-P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
> ES =0000 0000000000000000 ffffffff 00c00000
> CS =0010 0000000000000000 ffffffff 00a09b00 DPL=0 CS64 [-RA]
> SS =0000 0000000000000000 ffffffff 00c00000
> DS =0000 0000000000000000 ffffffff 00c00000
> FS =0000 0000000000000000 ffffffff 00c00000
> GS =0000 ffff8ac27fcc0000 ffffffff 00c00000
> LDT=0000 0000000000000000 ffffffff 00c00000
> TR =0040 fffffe0000096000 0000206f 00008b00 DPL=0 TSS64-busy
> GDT=     fffffe0000094000 0000007f
> IDT=     fffffe0000000000 00000fff
> CR0=80050033 CR2=0000000000000000 CR3=00000010ca40a001 CR4=003606e0
> DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 
> DR3=0000000000000000
> DR6=00000000fffe0ff0 DR7=0000000000000400
> EFER=0000000000000d01
> Code=0f 1f ... ...
> 
> Print the cpu->cpu_index in cpu_dump_state() and remove it from the caller.
> 
> Cc: Joe Jin <joe.jin@oracle.com>
> Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
> ---
>  hw/core/cpu-common.c      | 1 +
>  monitor/hmp-cmds-target.c | 2 --
>  softmmu/cpus.c            | 1 -
>  3 files changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/hw/core/cpu-common.c b/hw/core/cpu-common.c
> index 5ccc3837b6..d2503f2d09 100644
> --- a/hw/core/cpu-common.c
> +++ b/hw/core/cpu-common.c
> @@ -105,6 +105,7 @@ void cpu_dump_state(CPUState *cpu, FILE *f, int flags)
>  
>      if (cc->dump_state) {
>          cpu_synchronize_state(cpu);
> +        qemu_fprintf(f, "\nCPU#%d\n", cpu->cpu_index);
>          cc->dump_state(cpu, f, flags);
>      }
>  }
> diff --git a/monitor/hmp-cmds-target.c b/monitor/hmp-cmds-target.c
> index 0d3e84d960..f7dd354d2a 100644
> --- a/monitor/hmp-cmds-target.c
> +++ b/monitor/hmp-cmds-target.c
> @@ -99,7 +99,6 @@ void hmp_info_registers(Monitor *mon, const QDict *qdict)
>  
>      if (all_cpus) {
>          CPU_FOREACH(cs) {
> -            monitor_printf(mon, "\nCPU#%d\n", cs->cpu_index);
>              cpu_dump_state(cs, NULL, CPU_DUMP_FPU);
>          }
>      } else {
> @@ -114,7 +113,6 @@ void hmp_info_registers(Monitor *mon, const QDict *qdict)
>              return;
>          }
>  
> -        monitor_printf(mon, "\nCPU#%d\n", cs->cpu_index);
>          cpu_dump_state(cs, NULL, CPU_DUMP_FPU);
>      }
>  }
> diff --git a/softmmu/cpus.c b/softmmu/cpus.c
> index 9cbc8172b5..f69bbe6abc 100644
> --- a/softmmu/cpus.c
> +++ b/softmmu/cpus.c
> @@ -122,7 +122,6 @@ void hw_error(const char *fmt, ...)
>      vfprintf(stderr, fmt, ap);
>      fprintf(stderr, "\n");
>      CPU_FOREACH(cpu) {
> -        fprintf(stderr, "CPU #%d:\n", cpu->cpu_index);
>          cpu_dump_state(cpu, stderr, CPU_DUMP_FPU);
>      }
>      va_end(ap);