linux-kernel - Re: [PATCH v3 3/3] x86/mce: Add CMCI storm switching support for Zhaoxin

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Message-ID: <7a80b9f5-9503-45fa-bbf4-d0dfa97688ff@zhaoxin.com>
Date: Fri, 20 Sep 2024 18:42:22 +0800
From: Tony W Wang-oc <TonyWWang-oc@...oxin.com>
To: "Zhuo, Qiuxu" <qiuxu.zhuo@...el.com>, "tglx@...utronix.de"
	<tglx@...utronix.de>, "mingo@...hat.com" <mingo@...hat.com>, "bp@...en8.de"
	<bp@...en8.de>, "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
	"x86@...nel.org" <x86@...nel.org>, "hpa@...or.com" <hpa@...or.com>, "Luck,
 Tony" <tony.luck@...el.com>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "linux-edac@...r.kernel.org"
	<linux-edac@...r.kernel.org>
CC: "CobeChen@...oxin.com" <CobeChen@...oxin.com>, "TimGuo@...oxin.com"
	<TimGuo@...oxin.com>, "LeoLiu-oc@...oxin.com" <LeoLiu-oc@...oxin.com>, "Lyle
 Li" <LyleLi@...oxin.com>
Subject: Re: [PATCH v3 3/3] x86/mce: Add CMCI storm switching support for
 Zhaoxin



On 2024/9/20 17:17, Zhuo, Qiuxu wrote:
> 
>> From: Tony W Wang-oc <TonyWWang-oc@...oxin.com>
>> [...]
>> Subject: [PATCH v3 3/3] x86/mce: Add CMCI storm switching support for
>> [...]
>> --- a/arch/x86/kernel/cpu/mce/zhaoxin.c
>> +++ b/arch/x86/kernel/cpu/mce/zhaoxin.c
>> @@ -63,3 +63,21 @@ void mce_zhaoxin_feature_clear(struct cpuinfo_x86 *c)
>> {
>>        intel_clear_lmce();
>>   }
>> +
>> +void mce_zhaoxin_handle_storm(int bank, bool on) {
>> +     unsigned long flags;
>> +     u64 val;
>> +
>> +     raw_spin_lock_irqsave(&cmci_discover_lock, flags);
>> +     rdmsrl(MSR_IA32_MCx_CTL2(bank), val);
>> +     if (on) {
>> +             val &= ~(MCI_CTL2_CMCI_EN |
>> MCI_CTL2_CMCI_THRESHOLD_MASK);
>> +             val |= CMCI_STORM_THRESHOLD;
>> +     } else {
>> +             val &= ~MCI_CTL2_CMCI_THRESHOLD_MASK;
>> +             val |= (MCI_CTL2_CMCI_EN | cmci_threshold[bank]);
>> +     }
>> +     wrmsrl(MSR_IA32_MCx_CTL2(bank), val);
>> +     raw_spin_unlock_irqrestore(&cmci_discover_lock, flags); }
> 
> Are there any reasons or comments why it needs to disable/enable the CMCI interrupt
> here during a CMCI storm on/off? If not, then reuse mce_intel_handle_storm() to avoid
> duplicating the code.
> 

As explained in another email.
The reason is actually mentioned in the cover letter: "because Zhaoxin's 
UCR error is not reported through CMCI", and we want to disable CMCI 
interrupt when CMCI storm happened.

Sincerely
TonyWWang-oc