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

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Message-ID: <CY8PR11MB713412D068F202057A71CDE8896C2@CY8PR11MB7134.namprd11.prod.outlook.com>
Date: Fri, 20 Sep 2024 11:44:59 +0000
From: "Zhuo, Qiuxu" <qiuxu.zhuo@...el.com>
To: Tony W Wang-oc <TonyWWang-oc@...oxin.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

> From: Tony W Wang-oc <TonyWWang-oc@...oxin.com>
> [...]
> >> --- 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.

So, this is just you want to disable CMCI when a CMCI storm happens. 
This doesn't explain much to me.
What's the problem if not disable CMCI when a CMCI storm happens?