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Subject: Re: [PATCH 2/4] kvm: x86: allow set apic and ioapic debug dynamically
To:     Yi Wang <wang.yi59@zte.com.cn>
Cc:     rkrcmar@redhat.com, tglx@linutronix.de, mingo@redhat.com,
        bp@alien8.de, hpa@zytor.com, x86@kernel.org, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, xue.zhihong@zte.com.cn,
        up2wing@gmail.com, wang.liang82@zte.com.cn
References: <1561962071-25974-1-git-send-email-wang.yi59@zte.com.cn>
 <1561962071-25974-3-git-send-email-wang.yi59@zte.com.cn>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <685680d5-f642-0c48-08f2-8c73026ccaf0@redhat.com>
Date:   Wed, 3 Jul 2019 18:23:03 +0200
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On 01/07/19 08:21, Yi Wang wrote:
> There are two *_debug() macros in kvm apic source file:
> - ioapic_debug, which is disable using #if 0
> - apic_debug, which is commented
> 
> Maybe it's better to control these two macros using CONFIG_KVM_DEBUG,
> which can be set in make menuconfig.
> 
> Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
> ---
>  arch/x86/kvm/ioapic.c | 2 +-
>  arch/x86/kvm/lapic.c  | 5 ++++-
>  2 files changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c
> index 1add1bc..8099253 100644
> --- a/arch/x86/kvm/ioapic.c
> +++ b/arch/x86/kvm/ioapic.c
> @@ -45,7 +45,7 @@
>  #include "lapic.h"
>  #include "irq.h"
>  
> -#if 0
> +#ifdef CONFIG_KVM_DEBUG
>  #define ioapic_debug(fmt,arg...) printk(KERN_WARNING fmt,##arg)
>  #else
>  #define ioapic_debug(fmt, arg...)
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index 4924f83..dfff5c6 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -54,8 +54,11 @@
>  #define PRIu64 "u"
>  #define PRIo64 "o"
>  
> -/* #define apic_debug(fmt,arg...) printk(KERN_WARNING fmt,##arg) */
> +#ifdef CONFIG_KVM_DEBUG
> +#define apic_debug(fmt,arg...) printk(KERN_WARNING fmt,##arg)
> +#else
>  #define apic_debug(fmt, arg...) do {} while (0)
> +#endif
>  
>  /* 14 is the version for Xeon and Pentium 8.4.8*/
>  #define APIC_VERSION			(0x14UL | ((KVM_APIC_LVT_NUM - 1) << 16))
> 

I would just drop all of them.  I've never used them in years, the kvm
tracepoints are enough.

Paolo