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Date:   Tue, 10 Aug 2021 11:17:07 +0200
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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        linux-crypto@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Joerg Roedel <jroedel@suse.de>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ard Biesheuvel <ardb@kernel.org>,
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        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        David Rientjes <rientjes@google.com>,
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        Michael Roth <michael.roth@amd.com>,
        Vlastimil Babka <vbabka@suse.cz>, tony.luck@intel.com,
        npmccallum@redhat.com, brijesh.ksingh@gmail.com
Subject: Re: [PATCH Part1 RFC v4 02/36] x86/sev: Save the negotiated GHCB
 version
Message-ID: <YRJEE6C/NC3Epa8G@zn.tnic>
References: <20210707181506.30489-1-brijesh.singh@amd.com>
 <20210707181506.30489-3-brijesh.singh@amd.com>
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On Wed, Jul 07, 2021 at 01:14:32PM -0500, Brijesh Singh wrote:
> diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
> index 114f62fe2529..19c2306ac02d 100644
> --- a/arch/x86/kernel/sev-shared.c
> +++ b/arch/x86/kernel/sev-shared.c
> @@ -14,6 +14,15 @@
>  #define has_cpuflag(f)	boot_cpu_has(f)
>  #endif
>  
> +/*
> + * Since feature negotiation related variables are set early in the boot
> + * process they must reside in the .data section so as not to be zeroed
> + * out when the .bss section is later cleared.
> + *
> + * GHCB protocol version negotiated with the hypervisor.
> + */
> +static u16 ghcb_version __section(".data..ro_after_init");

There's a define for that section specifier: __ro_after_init

-- 
Regards/Gruss,
    Boris.

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