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

Sudeep Holla
2026-05-06T07:50:18Z

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