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Date:   Tue, 1 Feb 2022 19:08:21 +0100
From:   Borislav Petkov <bp@alien8.de>
To:     Brijesh Singh <brijesh.singh@amd.com>
Cc:     x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org,
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        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Joerg Roedel <jroedel@suse.de>,
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        "H. Peter Anvin" <hpa@zytor.com>, Ard Biesheuvel <ardb@kernel.org>,
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        David Rientjes <rientjes@google.com>,
        Dov Murik <dovmurik@linux.ibm.com>,
        Tobin Feldman-Fitzthum <tobin@ibm.com>,
        Michael Roth <michael.roth@amd.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        "Kirill A . Shutemov" <kirill@shutemov.name>,
        Andi Kleen <ak@linux.intel.com>,
        "Dr . David Alan Gilbert" <dgilbert@redhat.com>,
        brijesh.ksingh@gmail.com, tony.luck@intel.com, marcorr@google.com,
        sathyanarayanan.kuppuswamy@linux.intel.com
Subject: Re: [PATCH v9 05/43] x86/compressed/64: Detect/setup SEV/SME
 features earlier in boot
Message-ID: <Yfl3FaTGPxE7qMCq@zn.tnic>
References: <20220128171804.569796-1-brijesh.singh@amd.com>
 <20220128171804.569796-6-brijesh.singh@amd.com>
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In-Reply-To: <20220128171804.569796-6-brijesh.singh@amd.com>
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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.

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