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

Aneesh Kumar K.V (Arm) posted 12 patches 3 months, 1 week ago
[PATCH RESEND v2 03/12] coco: guest: arm64: Drop dummy RSI platform device stub
Posted by Aneesh Kumar K.V (Arm) 3 months, 1 week ago
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>
---
 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)
-- 
2.43.0
Re: [PATCH RESEND v2 03/12] coco: guest: arm64: Drop dummy RSI platform device stub
Posted by Jonathan Cameron 3 months, 1 week ago
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)