linux-kernel - Re: [PATCH] KVM: Only display message about bios support disabled once

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Message-ID: <YpD3a3wMbr9xIsub@google.com>
Date:   Fri, 27 May 2022 16:08:11 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Mario Limonciello <mario.limonciello@....com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        "open list:KERNEL VIRTUAL MACHINE FOR X86 (KVM/x86)" 
        <kvm@...r.kernel.org>,
        "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" 
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] KVM: Only display message about bios support disabled
 once

On Thu, May 26, 2022, Mario Limonciello wrote:
> On an OEM laptop I see the following message 10 times in my dmesg:
> "kvm: support for 'kvm_amd' disabled by bios"
> 
> This might be useful the first time, but there really isn't a point
> to showing the error 9 more times.  The BIOS still has it disabled.
> Change the message to only display one time.

NAK, this has been discussed multiple times in the past[1][2], there are edge cases
where logging multiple messages is desirable.  Even using a ratelimited printk is
essentially a workaround for a systemd bug[3], which I'm guessing is the cuplrit here.

[1] https://lore.kernel.org/all/20190826182320.9089-1-tony.luck@intel.com
[2] https://lore.kernel.org/all/20200214143035.607115-1-e.velu@criteo.com
[3] https://github.com/systemd/systemd/issues/14906