Re: [PATCH v7 1/5] efi: Save location of EFI confidential computing area

[Gerd Hoffmann]

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@xxxxxxxxxxxxx>

Reviewed-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>

take care,
  Gerd