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Date:   Mon, 7 Jun 2021 16:19:26 +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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        "H. Peter Anvin" <hpa@zytor.com>, Ard Biesheuvel <ardb@kernel.org>,
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        Jim Mattson <jmattson@google.com>,
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        David Rientjes <rientjes@google.com>, tony.luck@intel.com,
        npmccallum@redhat.com
Subject: Re: [PATCH Part1 RFC v3 05/22] x86/sev: Add support for hypervisor
 feature VMGEXIT
Message-ID: <YL4q7jHYu65I11bZ@zn.tnic>
References: <20210602140416.23573-1-brijesh.singh@amd.com>
 <20210602140416.23573-6-brijesh.singh@amd.com>
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On Wed, Jun 02, 2021 at 09:03:59AM -0500, Brijesh Singh wrote:
> diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
> index 70f181f20d92..94957c5bdb51 100644
> --- a/arch/x86/kernel/sev-shared.c
> +++ b/arch/x86/kernel/sev-shared.c

I'm guessing this is in sev-shared.c because it is going to be used by
both stages?

> @@ -20,6 +20,7 @@
>   * out when the .bss section is later cleared.
>   */
>  static u16 ghcb_version __section(".data");

State what this is:

/* Bitmap of SEV features supported by the hypervisor */

> +static u64 hv_features __section(".data");

Also, I'm assuming that bitmap remains immutable during the guest
lifetime so you can do:

static u64 hv_features __ro_after_init;

instead, which will do:

static u64 hv_features __attribute__((__section__(".data..ro_after_init")));

and it'll be in the data section and then also marked read-only after
init, after mark_rodata_ro() more specifically.

Thx.

-- 
Regards/Gruss,
    Boris.

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