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From:   Thomas Gleixner <tglx@linutronix.de>
To:     Xiaoyao Li <xiaoyao.li@intel.com>, Ingo Molnar <mingo@redhat.com>,
        Borislav Petkov <bp@alien8.de>, hpa@zytor.com,
        Paolo Bonzini <pbonzini@redhat.com>,
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Cc:     Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        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 1/9] x86/split_lock: Rework the initialization flow of split lock detection
In-Reply-To: <02ff2436-340c-540a-86b8-fa5f4ff7bb3b@intel.com>
References: <20200315050517.127446-1-xiaoyao.li@intel.com> <20200315050517.127446-2-xiaoyao.li@intel.com> <87zhc7ovhj.fsf@nanos.tec.linutronix.de> <87lfnqq0oo.fsf@nanos.tec.linutronix.de> <beb9ab5c-a50d-2ec6-1c23-e426508cdf4e@intel.com> <87tv2edp1a.fsf@nanos.tec.linutronix.de> <02ff2436-340c-540a-86b8-fa5f4ff7bb3b@intel.com>
Date:   Wed, 25 Mar 2020 01:52:58 +0100
Message-ID: <87blolz251.fsf@nanos.tec.linutronix.de>
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Xiaoyao Li <xiaoyao.li@intel.com> writes:
> On 3/24/2020 6:29 PM, Thomas Gleixner wrote:
>> -	switch (sld_state) {
>> +	switch (state) {
>>   	case sld_off:
>>   		pr_info("disabled\n");
>> -		break;
>> -
>> +		return;
> Here, when sld_off, it just returns without 
> setup_force_cpu_cap(X86_FEATURE_SPLIT_LOCK_DETECT).
>
> So for APs, it won't clear SLD bit in split_lock_init().

Trivial fix:

static void split_lock_init(void)
{
	split_lock_verify_msr(sld_state != sld_off);
}

You just need to remove the __init annotation from split_lock_verify_msr().

Thanks,

        tglx