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From: Ingo Molnar <mingo@kernel.org>
To: Ashok Raj <ashok.raj@intel.com>
Cc: Borislav Petkov <bp@alien8.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Tony Luck <tony.luck@intel.com>,
	Dave Hansen <dave.hansen@intel.com>,
	LKML Mailing List <linux-kernel@vger.kernel.org>,
	X86-kernel <x86@kernel.org>,
	Andy Lutomirski <luto@amacapital.net>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	Jacon Jun Pan <jacob.jun.pan@intel.com>
Subject: Re: [PATCH v3 3/5] x86/microcode: Avoid any chance of MCE's during microcode update
Date: Wed, 17 Aug 2022 09:58:03 +0200	[thread overview]
Message-ID: <Yvyfi9XC8bu0cOG+@gmail.com> (raw)
In-Reply-To: <Yvybq+hYT4tG/yAg@gmail.com>


* Ingo Molnar <mingo@kernel.org> wrote:

> > +void mce_set_mcip(void)
> > +{
> > +	mce_wrmsrl(MSR_IA32_MCG_STATUS, 0x1);
> > +}
> > +
> > +void mce_clear_mcip(void)
> > +{
> > +	mce_wrmsrl(MSR_IA32_MCG_STATUS, 0x0);
> > +}
> 
> Instead of naming new APIs after how they are doing stuff, please name them 
> after *what* they are doing at the highest level: they disable/enable MCEs.
> 
> Ie. I'd suggest something like:
> 
>      mce_disable()
>      mce_enable()
> 
> I'd also suggest to at minimum add a WARN_ON_ONCE() if MSR_IA32_MCG_STATUS 
> is already 1 when we disable it - because whoever wanted it disabled will 
> now be surprised by us enabling them again.

Also, Boris tells me that writing 0x0 to MSR_IA32_MCG_STATUS apparently 
shuts the platform down - which is not ideal...

Thanks,

	Ingo

  reply	other threads:[~2022-08-17  7:58 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-17  5:11 [PATCH v3 0/5] Making microcode late-load robust Ashok Raj
2022-08-17  5:11 ` [PATCH v3 1/5] x86/microcode/intel: Check against CPU signature before saving microcode Ashok Raj
2022-08-17  7:43   ` Ingo Molnar
2022-08-17 10:45     ` Ashok Raj
2022-08-19 10:24   ` Borislav Petkov
2022-08-23 11:13     ` Ashok Raj
2022-08-24 19:27       ` Borislav Petkov
2022-08-25  3:27         ` Ashok Raj
2022-08-26 16:24           ` Borislav Petkov
2022-08-26 17:18             ` Ashok Raj
2022-08-26 17:29               ` Borislav Petkov
2022-08-17  5:11 ` [PATCH v3 2/5] x86/microcode/intel: Allow a late-load only if a min rev is specified Ashok Raj
2022-08-17  7:45   ` Ingo Molnar
2022-08-19 11:11   ` Borislav Petkov
2022-08-23  0:08     ` Ashok Raj
2022-08-24 19:52       ` Borislav Petkov
2022-08-25  4:02         ` Ashok Raj
2022-08-26 12:09           ` Borislav Petkov
2022-08-17  5:11 ` [PATCH v3 3/5] x86/microcode: Avoid any chance of MCE's during microcode update Ashok Raj
2022-08-17  7:41   ` Ingo Molnar
2022-08-17  7:58     ` Ingo Molnar [this message]
2022-08-17  8:09       ` Borislav Petkov
2022-08-17 11:57         ` Ashok Raj
2022-08-17 12:10           ` Borislav Petkov
2022-08-17 12:30             ` Ashok Raj
2022-08-17 14:19               ` Borislav Petkov
2022-08-17 15:06                 ` Ashok Raj
2022-08-29 14:23                   ` Andy Lutomirski
2022-08-17 11:40     ` Ashok Raj
2022-08-17  5:11 ` [PATCH v3 4/5] x86/x2apic: Support x2apic self IPI with NMI_VECTOR Ashok Raj
2022-08-17  5:11 ` [PATCH v3 5/5] x86/microcode: Place siblings in NMI loop while update in progress Ashok Raj
2022-08-30 19:15   ` Andy Lutomirski

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