Re: [PATCH v13 7/8] coco: guest: arm64: Add sysfs ABI for CCA Realm guests

[Suzuki K Poulose]

On 23/09/2026 15:04, Aneesh Kumar K.V (Arm) wrote:
> Userspace has used the arm-cca-dev platform device to detect Arm CCA
> Realm guests. Removing it without a replacement would break that
> detection and would also leave userspace depending on kernel
> device-model details.
>
> Add /sys/firmware/cca/realm_guest as a stable ABI for detecting whether
> the kernel is running as an Arm CCA Realm guest. Create the file only in
> Realm world, where it reads 1.
>
> Document the new ABI in Documentation/ABI/testing/sysfs-firmware-cca.
>
> Link: https://lore.kernel.org/all/4a7d84b2-2ec4-4773-a2d5-7b63d5c683cf@xxxxxxx
> Reviewed-by: Jonathan Cameron <jonathan.cameron@xxxxxxxxxxxxxxxx>
> Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@xxxxxxxxxx>

Reviewed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>