Re: [RFC PATCH 1/3] arm64: KVM: defer kvm_init() to finalise_pkvm() when pKVM is enabled

[Sudeep Holla <sudeep.holla@kernel.org>]

On Tue, May 05, 2026 at 10:54:07AM +0100, Yeoreum Yun wrote:
> This patch is a preparatory change to address dependency issues
> between the FF-A driver and pKVM.
> 
> kvm_init() should be invoked from finalise_pkvm(),
> as this is the point where pKVM initialisation is finalised and
> the system transitions into the protected mode.
> 
> Deferring kvm_init() ensures that KVM is initialised only after pKVM has
> fully established its protected environment.
> 
> Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> ---
>  arch/arm64/kvm/arm.c  |  8 +++++---
>  arch/arm64/kvm/pkvm.c | 15 ++++++++++++++-
>  2 files changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 8bb2c7422cc8..663b1d447a9b 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -3025,9 +3025,11 @@ static __init int kvm_arm_init(void)
>  	 * FIXME: Do something reasonable if kvm_init() fails after pKVM
>  	 * hypervisor protection is finalized.
>  	 */
> -	err = kvm_init(sizeof(struct kvm_vcpu), 0, THIS_MODULE);
> -	if (err)
> -		goto out_subs;
> +	if (!is_protected_kvm_enabled()) {
> +		err = kvm_init(sizeof(struct kvm_vcpu), 0, THIS_MODULE);
> +		if (err)
> +			goto out_subs;
> +	}
>  
>  	/*
>  	 * This should be called after initialization is done and failure isn't
> diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
> index 053e4f733e4b..48b06d384570 100644
> --- a/arch/arm64/kvm/pkvm.c
> +++ b/arch/arm64/kvm/pkvm.c
> @@ -17,6 +17,7 @@
>  #include "hyp_constants.h"
>  
>  DEFINE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
> +EXPORT_SYMBOL_GPL(kvm_protected_mode_initialized);
>

I am not sure if this is needed when FF-A is built as module. If others
are OK with it, I am fine. But I am thinking if we need to use this in
FF-A driver which can be built-in or a module, we can add
IS_BUILTIN(CONFIG_ARM_FFA_*)

-- 
Regards,
Sudeep