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Message-ID: <3b590f05-ff48-8cad-8e2d-e4ea339daf9c@linux.ibm.com>
Date:   Fri, 1 Apr 2022 08:15:03 +0300
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Subject: Re: [PATCH v9 3/4] efi: Register efi_secret platform device if EFI
 secret area is declared
Content-Language: en-US
To:     linux-efi@vger.kernel.org
Cc:     Borislav Petkov <bp@suse.de>, Ashish Kalra <ashish.kalra@amd.com>,
        Brijesh Singh <brijesh.singh@amd.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        James Morris <jmorris@namei.org>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        Andi Kleen <ak@linux.intel.com>,
        Greg KH <gregkh@linuxfoundation.org>,
        Andrew Scull <ascull@google.com>,
        Dave Hansen <dave.hansen@intel.com>,
        "Dr. David Alan Gilbert" <dgilbert@redhat.com>,
        Gerd Hoffmann <kraxel@redhat.com>,
        Lenny Szubowicz <lszubowi@redhat.com>,
        Peter Gonda <pgonda@google.com>,
        Matthew Garrett <mjg59@srcf.ucam.org>,
        James Bottomley <jejb@linux.ibm.com>,
        Tobin Feldman-Fitzthum <tobin@linux.ibm.com>,
        Jim Cadden <jcadden@ibm.com>,
        Daniele Buono <dbuono@linux.vnet.ibm.com>,
        linux-coco@lists.linux.dev, linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org, Dov Murik <dovmurik@linux.ibm.com>
References: <20220331215607.3182232-1-dovmurik@linux.ibm.com>
 <20220331215607.3182232-4-dovmurik@linux.ibm.com>
From:   Dov Murik <dovmurik@linux.ibm.com>
In-Reply-To: <20220331215607.3182232-4-dovmurik@linux.ibm.com>
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On 01/04/2022 0:56, Dov Murik wrote:
> During efi initialization, check if coco_secret is defined in the EFI
> configuration table; in such case, register platform device
> "efi_secret".  This allows udev to automatically load the efi_secret
> module (platform driver), which in turn will populate the
> <securityfs>/secrets/coco directory in guests into which secrets were
> injected.
> 
> Note that a declared address of an EFI secret area doesn't mean that
> secrets where indeed injected to that area; if the secret area is not
> populated, the driver will not load (but the platform device will still
> be registered).
> 
> Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>
> ---
>  drivers/firmware/efi/efi.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 378d044b2463..b92eabc554e6 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -425,6 +425,9 @@ static int __init efisubsys_init(void)
>  	if (efi_enabled(EFI_DBG) && efi_enabled(EFI_PRESERVE_BS_REGIONS))
>  		efi_debugfs_init();
>  
> +	if (efi.coco_secret != EFI_INVALID_TABLE_ADDR)
> +		platform_device_register_simple("efi_secret", 0, NULL, 0);

These two lines should be wrapped by #ifdef CONFIG_EFI_COCO_SECRET .
I'll fix that for the next round.

-Dov

> +
>  	return 0;
>  
>  err_remove_group: