linux-kernel - Re: [PATCH v2 08/16] x86/mce/amd: Clean up enable_deferred_error

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Message-ID: <20240429131240.GOZi-cyLh2OhRrNTWM@fat_crate.local>
Date: Mon, 29 Apr 2024 15:12:40 +0200
From: Borislav Petkov <bp@...en8.de>
To: Yazen Ghannam <yazen.ghannam@....com>
Cc: linux-edac@...r.kernel.org, linux-kernel@...r.kernel.org,
	tony.luck@...el.com, x86@...nel.org, Avadhut.Naik@....com,
	John.Allen@....com
Subject: Re: [PATCH v2 08/16] x86/mce/amd: Clean up
 enable_deferred_error_interrupt()

On Thu, Apr 04, 2024 at 10:13:51AM -0500, Yazen Ghannam wrote:
> -/* Deferred error settings */
> +/* MCA Interrupt Configuration register, one per CPU */

SMCA?

>  #define MSR_CU_DEF_ERR		0xC0000410
> -#define MASK_DEF_LVTOFF		0x000000F0
> -#define MASK_DEF_INT_TYPE	0x00000006
> -#define DEF_INT_TYPE_APIC	0x2
> +#define MSR_MCA_INTR_CFG		0xC0000410

You do see those other MSRs' prefixes, right?

MSR_AMD64_SMCA_...

Is this one not part of the SMCA arch?

> +#define INTR_CFG_DFR_LVT_OFFSET		GENMASK_ULL(7, 4)
> +#define INTR_CFG_LEGACY_DFR_INTR_TYPE	GENMASK_ULL(2, 1)
>  #define INTR_TYPE_APIC			0x1

Ditto for its bit(s) names.

> +static u64 get_mca_intr_cfg(void)
> +{
> +	u64 mca_intr_cfg;
> +
> +	if (!mce_flags.succor)
> +		return 0;
> +
> +	if (rdmsrl_safe(MSR_MCA_INTR_CFG, &mca_intr_cfg))
> +		return 0;
> +
> +	return mca_intr_cfg;
> +}

This is an overkill. If we add a function for every MSR we're reading...

Do this differently: prepare the value you're writing back into the
INTR_CFG MSR once, save it into mca_intr_cfg and then write it on each
core at the end of enable_deferred_error_interrupt().

And make u64 mca_intr_cfg static global to amd.c so that you can refer
to it from outside of the functions and then you don't have to pass it
around as a function param.

Thx.

-- 
Regards/Gruss,
    Boris.

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