linux-kernel - Re: [v2 01/13] x86/microcode/intel: Prevent printing updated microcode rev multiple times

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Date:   Sun, 6 Nov 2022 14:35:58 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Ashok Raj <ashok.raj@...el.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        LKML Mailing List <linux-kernel@...r.kernel.org>,
        X86-kernel <x86@...nel.org>, Tony Luck <tony.luck@...el.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Arjan van de Ven <arjan.van.de.ven@...el.com>,
        Andy Lutomirski <luto@...nel.org>,
        Jacon Jun Pan <jacob.jun.pan@...el.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Kai Huang <kai.huang@...el.com>,
        Andrew Cooper <andrew.cooper3@...rix.com>
Subject: Re: [v2 01/13] x86/microcode/intel: Prevent printing updated
 microcode rev multiple times

On Thu, Nov 03, 2022 at 05:58:49PM +0000, Ashok Raj wrote:
> @@ -696,8 +697,7 @@ static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
>  
>  	csig->rev = c->microcode;
>  
> -	/* No extra locking on prev, races are harmless. */
> -	if (csig->sig != prev.sig || csig->pf != prev.pf || csig->rev != prev.rev) {
> +	if (bsp && csig->rev != prev.rev) {
>  		pr_info("sig=0x%x, pf=0x%x, revision=0x%x\n",
>  			csig->sig, csig->pf, csig->rev);

And now that we've established that we don't do mixed steppings anymore
and the microcode revision is the same system-wide, you should simply
drop this pr_info(), in your next patch you're adding

+static u32 early_old_rev;

That thing should simply be

/* Currently applied microcode revision */
static u32 microcode_rev;

and you simply update that one each time you update microcode and print
it as the previous and the new one and then write the new one into this
var and that's it. Simple.

Thx.

-- 
Regards/Gruss,
    Boris.

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