Re: [PATCH 0/3] arm64: realm: Add support for encrypted data from firmware

[Suzuki K Poulose <suzuki.poulose@arm.com>]

On 13/06/2025 12:11, Suzuki K Poulose wrote:
> Confidential compute firmware may provide secret data via reserved memory regions
> (e.g., ACPI CCEL, EFI Coco secret area). These must be ioremap'ed() as encrypted.
> As of now, realm only maps "trusted devices" (RIPAS = RSI_RIPAS_DEV) as encrypted.
> This series adds support for mapping areas that are protected
> (i.e., RIPAS = RSI_RIPAS_RAM) as encrypted. Also, extrapolating that, we can map
> anything that is not RIPAS_EMPTY as protected, as it is guaranteed to be "protected".
> 
> With this in place, we can naturally map any firmware provided area based on the
> RIPAS value. If the firmware provides a shared region (not trusted), it must have
> set the RIPAS accordingly, before placing the data, as the transition is always
> destructive.
> 
> Also enables the EFI Coco secret area support and Confidential Compute Event
> Log (CCEL) for arm64.
> 

A branch with the patches is also available here:

git@git.gitlab.arm.com:linux-arm/linux-cca.git  cca-guest/coco-secret/v1


Suzuki


> 
> Suzuki K Poulose (3):
>    arm64: realm: ioremap: Allow mapping memory as encrypted
>    arm64: Enable EFI secret area Securityfs support
>    arm64: acpi: Enable ACPI CCEL support
> 
>   arch/arm64/include/asm/io.h          |  6 +++++-
>   arch/arm64/include/asm/rsi.h         |  2 +-
>   arch/arm64/kernel/acpi.c             |  5 +++++
>   arch/arm64/kernel/rsi.c              | 26 ++++++++++++++++++++++----
>   drivers/virt/coco/efi_secret/Kconfig |  2 +-
>   5 files changed, 34 insertions(+), 7 deletions(-)
>