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From:   Thomas Gleixner <tglx@linutronix.de>
To:     Sean Christopherson <sean.j.christopherson@intel.com>
Cc:     Xiaoyao Li <xiaoyao.li@intel.com>, Ingo Molnar <mingo@redhat.com>,
        Borislav Petkov <bp@alien8.de>, hpa@zytor.com,
        Paolo Bonzini <pbonzini@redhat.com>, kvm@vger.kernel.org,
        x86@kernel.org, linux-kernel@vger.kernel.org,
        Andy Lutomirski <luto@kernel.org>,
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        Arvind Sankar <nivedita@alum.mit.edu>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Tony Luck <tony.luck@intel.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Jim Mattson <jmattson@google.com>
Subject: Re: [PATCH v5 3/9] x86/split_lock: Re-define the kernel param option for split_lock_detect
In-Reply-To: <20200324180207.GD5998@linux.intel.com>
References: <20200315050517.127446-1-xiaoyao.li@intel.com> <20200315050517.127446-4-xiaoyao.li@intel.com> <87r1xjov3a.fsf@nanos.tec.linutronix.de> <e708f6d2-8f96-903c-0bce-2eeecc4a237d@intel.com> <87r1xidoj1.fsf@nanos.tec.linutronix.de> <20200324180207.GD5998@linux.intel.com>
Date:   Tue, 24 Mar 2020 19:42:29 +0100
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Sean Christopherson <sean.j.christopherson@intel.com> writes:
> On Tue, Mar 24, 2020 at 11:40:18AM +0100, Thomas Gleixner wrote:
>> 
>> It's very much about whether the host is split lock clean.
>> 
>> If your host kernel is not, then this wants to be fixed first. If your
>> host application is broken, then either fix it or use "warn".
>
> The "kvm only" option was my suggestion.  The thought was to provide a way
> for users to leverage KVM to debug/test kernels without having to have a
> known good kernel and/or to minimize the risk of crashing their physical
> system.  E.g. debug a misbehaving driver by assigning its associated device
> to a guest.

warn is giving you that, right? I won't crash the host because the #AC
triggers in guest context.

Thanks,

        tglx