linux-kernel - Re: [PATCH 02/13] x86/microcode: Do not load from filesystem for CPU hot add

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Date:   Wed, 19 Oct 2022 19:52:32 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Ashok Raj <ashok.raj@...el.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Tony Luck <tony.luck@...el.com>,
        Dave Hansen <dave.hansen@...el.com>,
        LKML Mailing List <linux-kernel@...r.kernel.org>,
        X86-kernel <x86@...nel.org>,
        Tom Lendacky <thomas.lendacky@....com>,
        Arjan van de Ven <arjan.van.de.ven@...el.com>,
        Jacob Jun Pan <jacob.jun.pan@...el.com>
Subject: Re: [PATCH 02/13] x86/microcode: Do not load from filesystem for CPU
 hot add

On Fri, Oct 14, 2022 at 01:09:02PM -0700, Ashok Raj wrote:
> When request_microcode_fw() is called, refresh_fw parameter must be set
> only when late loading. Currently during CPU hotplug, the path is as
> follows.
> 
> mc_device_add() -> microcode_init_cpu() ->
> 				request_microcode_fw(refresh_hw=true)

So that ugly refresh_fw thing was getting on my nerves for a while
now so I took a long stern look today. And ended up axing off a lot
of ancient crud which was simply getting in the way and is completely
useless.

The diffstat says it all:

 arch/x86/include/asm/microcode.h      |   4 +-
 arch/x86/kernel/cpu/intel.c           |   1 -
 arch/x86/kernel/cpu/microcode/amd.c   |   5 +-
 arch/x86/kernel/cpu/microcode/core.c  | 214 ++++++++++++++++++-------------------------------------------------------------
 arch/x86/kernel/cpu/microcode/intel.c |   3 +-
 5 files changed, 52 insertions(+), 175 deletions(-)

and initial smoke-testing with CPU hotplug and suspend looks good.

I'll hammer on it some more in the coming days.

Patches as a reply to this message.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette