linux-kernel - Re: [PATCH 11/11] x86/kvm: Silence per-cpu pr_info noise about KVM clocks and steal time

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Date:   Thu, 9 Dec 2021 18:39:13 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     David Woodhouse <dwmw2@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        rcu@...r.kernel.org, mimoja@...oja.de, hewenliang4@...wei.com,
        hushiyuan@...wei.com, luolongjun@...wei.com, hejingxian@...wei.com
Subject: Re: [PATCH 11/11] x86/kvm: Silence per-cpu pr_info noise about KVM
 clocks and steal time

On 12/9/21 16:09, David Woodhouse wrote:
> From: David Woodhouse<dwmw@...zon.co.uk>
> 
> I made the actual CPU bringup go nice and fast... and then Linux spends
> half a minute printing stupid nonsense about clocks and steal time for
> each of 256 vCPUs. Don't do that. Nobody cares.

Queued this one, it makes sense even without the rest of the series.

Paolo

> Signed-off-by: David Woodhouse<dwmw@...zon.co.uk>
> ---
>   arch/x86/kernel/kvm.c      | 6 +++---
>   arch/x86/kernel/kvmclock.c | 2 +-
>   2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index 59abbdad7729..a438217cbfac 100644
> --- a/arch/x86/kernel/kvm.c
> +++ b/arch/x86/kernel/kvm.c
> @@ -313,7 +313,7 @@ static void kvm_register_steal_time(void)
>   		return;
>   
>   	wrmsrl(MSR_KVM_STEAL_TIME, (slow_virt_to_phys(st) | KVM_MSR_ENABLED));
> -	pr_info("stealtime: cpu %d, msr %llx\n", cpu,
> +	pr_debug("stealtime: cpu %d, msr %llx\n", cpu,
>   		(unsigned long long) slow_virt_to_phys(st));
>   }
>   
> @@ -350,7 +350,7 @@ static void kvm_guest_cpu_init(void)
>   
>   		wrmsrl(MSR_KVM_ASYNC_PF_EN, pa);
>   		__this_cpu_write(apf_reason.enabled, 1);
> -		pr_info("setup async PF for cpu %d\n", smp_processor_id());
> +		pr_debug("setup async PF for cpu %d\n", smp_processor_id());
>   	}
>   
>   	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) {
> @@ -376,7 +376,7 @@ static void kvm_pv_disable_apf(void)
>   	wrmsrl(MSR_KVM_ASYNC_PF_EN, 0);
>   	__this_cpu_write(apf_reason.enabled, 0);
>   
> -	pr_info("disable async PF for cpu %d\n", smp_processor_id());
> +	pr_debug("disable async PF for cpu %d\n", smp_processor_id());
>   }
>   
>   static void kvm_disable_steal_time(void)
> diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
> index 462dd8e9b03d..a35cbf9107af 100644
> --- a/arch/x86/kernel/kvmclock.c
> +++ b/arch/x86/kernel/kvmclock.c
> @@ -174,7 +174,7 @@ static void kvm_register_clock(char *txt)
>   
>   	pa = slow_virt_to_phys(&src->pvti) | 0x01ULL;
>   	wrmsrl(msr_kvm_system_time, pa);
> -	pr_info("kvm-clock: cpu %d, msr %llx, %s", smp_processor_id(), pa, txt);
> +	pr_debug("kvm-clock: cpu %d, msr %llx, %s", smp_processor_id(), pa, txt);
>   }
>   
>   static void kvm_save_sched_clock_state(void)
> -- 2.31.1
>