Re: [PATCH v2 08/11] KVM: x86: Print error code in exception injection tracepoint iff valid

From: Maxim Levitsky <mlevitsk@redhat.com>
To: Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Maciej S . Szmigiero" <maciej.szmigiero@oracle.com>
Subject: Re: [PATCH v2 08/11] KVM: x86: Print error code in exception injection tracepoint iff valid
Date: Thu, 28 Apr 2022 12:49:44 +0300	[thread overview]
Message-ID: <79a0c1205b646ead0b2128147cb7df4198646b99.camel@redhat.com> (raw)
In-Reply-To: <20220423021411.784383-9-seanjc@google.com>

On Sat, 2022-04-23 at 02:14 +0000, Sean Christopherson wrote:
> Print the error code in the exception injection tracepoint if and only if
> the exception has an error code.  Define the entire error code sequence
> as a set of formatted strings, print empty strings if there's no error
> code, and abuse __print_symbolic() by passing it an empty array to coerce
> it into printing the error code as a hex string.
> 
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
>  arch/x86/kvm/trace.h | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
> index d07428e660e3..385436d12024 100644
> --- a/arch/x86/kvm/trace.h
> +++ b/arch/x86/kvm/trace.h
> @@ -376,10 +376,11 @@ TRACE_EVENT(kvm_inj_exception,
>  		__entry->reinjected	= reinjected;
>  	),
>  
> -	TP_printk("%s (0x%x)%s",
> +	TP_printk("%s%s%s%s%s",
>  		  __print_symbolic(__entry->exception, kvm_trace_sym_exc),
> -		  /* FIXME: don't print error_code if not present */
> -		  __entry->has_error ? __entry->error_code : 0,
> +		  !__entry->has_error ? "" : " (",
> +		  !__entry->has_error ? "" : __print_symbolic(__entry->error_code, { }),
> +		  !__entry->has_error ? "" : ")",
>  		  __entry->reinjected ? " [reinjected]" : "")
>  );
>  

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>

Good idea to do it in few more places, I'll keep that in mind.

Best regards,
	Maxim Levitsky