linux-kernel - Re: [PATCH v4] x86/msr: Add write msr notrace to avoid the debug codes splash

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Date:   Wed, 26 Oct 2016 16:02:08 +0800
From:   Wanpeng Li <kernellwp@...il.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Wanpeng Li <wanpeng.li@...mail.com>,
        Ingo Molnar <mingo@...nel.org>, Mike Galbraith <efault@....de>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH v4] x86/msr: Add write msr notrace to avoid the debug
 codes splash

2016-10-26 15:56 GMT+08:00 Paolo Bonzini <pbonzini@...hat.com>:
>
>
> On 26/10/2016 09:55, Wanpeng Li wrote:
>>>> >> -static void kvm_guest_apic_eoi_write(u32 reg, u32 val)
>>>> >> +static void kvm_guest_apic_eoi_write_notrace(u32 reg, u32 val)
>>> >
>>> > Huh, this is not notrace?!?
>> Sorry, maybe I misunderstand you.
>>
>> ack_APIC_irq()
>>   -> apic_eoi()
>>     -> apic->eoi_write()
>>       -> kvm_guest_apic_eoi_write()
>>         -> apic->native_eoi_write()
>>           -> native_apic_msr_eoi_write()
>>             -> wrmsr_notrace()
>>               -> native_write_msr_notrace()
>>           -> native_apic_mem_write()
>>
>> The call path is notrace. Where I miss?
>
> kvm_guest_apic_eoi_write should be marked as notrace, shouldn't it?

I see. notrace static void kvm_guest_apic_eoi_write_notrace(u32 reg,
u32 val) and notrace static void kvm_guest_apic_eoi_write(u32 reg, u32
val), which one you prefer?

Regards,
Wanpeng Li