Re: [PATCH v9 05/43] x86/compressed/64: Detect/setup SEV/SME features earlier in boot

[Borislav Petkov]

On Fri, Jan 28, 2022 at 11:17:26AM -0600, Brijesh Singh wrote:
> diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
> index fd9441f40457..49064a9f96e2 100644
> --- a/arch/x86/boot/compressed/head_64.S
> +++ b/arch/x86/boot/compressed/head_64.S
> @@ -191,9 +191,8 @@ SYM_FUNC_START(startup_32)
>  	/*
>  	 * Mark SEV as active in sev_status so that startup32_check_sev_cbit()
>  	 * will do a check. The sev_status memory will be fully initialized

That "sev_status memory" formulation is just weird. Pls fix it while
you're touching that comment.

> +static inline u64 rd_sev_status_msr(void)
> +{
> +	unsigned long low, high;
> +
> +	asm volatile("rdmsr" : "=a" (low), "=d" (high) :
> +			"c" (MSR_AMD64_SEV));
> +
> +	return ((high << 32) | low);
> +}

Don't you see sev_es_rd_ghcb_msr() in that same file above? Do a common
rdmsr() helper and call it where needed, pls, instead of duplicating
code.

misc.h looks like a good place.

Extra bonus points will be given if you unify callers in
arch/x86/boot/cpucheck.c too but you don't have to - I can do that
ontop.

Thx.

-- 
Regards/Gruss,
    Boris.

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