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

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Message-ID: <d217a7c4-f86d-7437-7b58-6d2c8e5f71dc@redhat.com>
Date:   Wed, 26 Oct 2016 09:56:31 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Wanpeng Li <kernellwp@...il.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



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?

Paolo