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Date:   Wed, 2 Feb 2022 09:38:22 +0100
From:   Gerd Hoffmann <kraxel@redhat.com>
To:     Dov Murik <dovmurik@linux.ibm.com>
Cc:     linux-efi@vger.kernel.org, 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>,
        Lenny Szubowicz <lszubowi@redhat.com>,
        Peter Gonda <pgonda@google.com>,
        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
Subject: Re: [PATCH v7 1/5] efi: Save location of EFI confidential computing
 area
Message-ID: <20220202083822.fgyamauzqco374u2@sirius.home.kraxel.org>
References: <20220201124413.1093099-1-dovmurik@linux.ibm.com>
 <20220201124413.1093099-2-dovmurik@linux.ibm.com>
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On Tue, Feb 01, 2022 at 12:44:09PM +0000, Dov Murik wrote:
> Confidential computing (coco) hardware such as AMD SEV (Secure Encrypted
> Virtualization) allows a guest owner to inject secrets into the VMs
> memory without the host/hypervisor being able to read them.
> 
> Firmware support for secret injection is available in OVMF, which
> reserves a memory area for secret injection and includes a pointer to it
> the in EFI config table entry LINUX_EFI_COCO_SECRET_TABLE_GUID.
> 
> If EFI exposes such a table entry, uefi_init() will keep a pointer to
> the EFI config table entry in efi.coco_secret, so it can be used later
> by the kernel (specifically drivers/virt/coco/efi_secret).  It will also
> appear in the kernel log as "CocoSecret=ADDRESS"; for example:
> 
>     [    0.000000] efi: EFI v2.70 by EDK II
>     [    0.000000] efi: CocoSecret=0x7f22e680 SMBIOS=0x7f541000 ACPI=0x7f77e000 ACPI 2.0=0x7f77e014 MEMATTR=0x7ea0c018
> 
> The new functionality can be enabled with CONFIG_EFI_COCO_SECRET=y.
> 
> Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>

Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>

take care,
  Gerd