Re: [PATCH RESEND v2 03/12] coco: guest: arm64: Drop dummy RSI platform device stub

Jonathan Cameron
2025-10-29T16:54:18Z

On Mon, 27 Oct 2025 15:25:53 +0530
"Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org> wrote:

> The SMCCC firmware driver now creates the `arm-smccc` platform device
> and also creates the CCA auxiliary devices once the RSI ABI is
> discovered. This makes the arch-specific arm64_create_dummy_rsi_dev()
> helper redundant. Remove the arm-cca-dev platform device registration
> and let the SMCCC probe manage the RSI device.
>
> systemd match on platform:arm-cca-dev for confidential vm detection [1].
> Losing the platform device registration can break that. Keeping this
> removal in its own change makes it easy to revert if that regression
> blocks the rollout.
>
> [1] https://lore.kernel.org/all/4a7d84b2-2ec4-4773-a2d5-7b63d5c683cf@arm.com
>
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
Fair enough keeping it separate for now I guess.
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>

(and I see from that thread I did look at the RFC but clearly forgot all
about it :( )
> ---
> arch/arm64/kernel/rsi.c | 15 ---------------
> 1 file changed, 15 deletions(-)
>
> diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c
> index 5d711942e543..1b716d18b80e 100644
> --- a/arch/arm64/kernel/rsi.c
> +++ b/arch/arm64/kernel/rsi.c
> @@ -158,18 +158,3 @@ void __init arm64_rsi_init(void)
>
> static_branch_enable(&rsi_present);
> }
> -
> -static struct platform_device rsi_dev = {
> - .name = "arm-cca-dev",
> - .id = PLATFORM_DEVID_NONE
> -};
> -
> -static int __init arm64_create_dummy_rsi_dev(void)
> -{
> - if (is_realm_world() &&
> - platform_device_register(&rsi_dev))
> - pr_err("failed to register rsi platform device\n");
> - return 0;
> -}
> -
> -arch_initcall(arm64_create_dummy_rsi_dev)