# Re: \[PATCH v10 7/7\] coco: guest: arm64: Replace dummy CCA device with sysfs ABI

- From: Jason Gunthorpe \<jgg@nvidia.com\>
- Date: 2026-09-04 19:40:19 
- List: linux-arm-kernel
- Page: https://ratatoskr.run/linux-arm-kernel/2026/09/17516519
- Thread: https://ratatoskr.run/linux-coco/2026/09/17512666/t.md

```text
On Fri, 04 Sep 2026 15:20:00 +0530, Aneesh Kumar K.V (Arm) [ref] wrote:
> The SMCCC firmware driver now creates the arm-smccc platform device and
> instantiates the CCA RSI auxiliary devices once the RSI ABI is discovered.
> The arm64-specific arm-cca-dev platform device stub is therefore no longer
> needed.
> 
> However, userspace has used the arm-cca-dev platform device to detect Arm
> CCA Realm guests [1]. Removing it without a replacement would break that
> detection and would also leave userspace depending on kernel device-model
> details.
> 
> [...]

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

-- 
Jason

```