Re: [PATCH v2 4/8] KVM: arm64: Move PSCI helper functions to a shared header

[Vincent Donnefort <vdonnefort@google.com>]

On Fri, Jun 19, 2026 at 08:07:15AM +0100, Fuad Tabba wrote:
> Move kvm_psci_valid_affinity() and kvm_psci_narrow_to_32bit() from
> psci.c to include/kvm/arm_psci.h, and move psci_affinity_mask() there
> too, renaming it kvm_psci_affinity_mask() now that it is no longer
> file-local. A follow-up series handles some protected-guest PSCI calls
> at EL2 using these helpers.
> 
> No functional change intended.
> 
> Signed-off-by: Fuad Tabba <tabba@google.com>

Reviewed-by: Vincent Donnefort <vdonnefort@google.com>

> ---
>  arch/arm64/kvm/psci.c  | 30 +-----------------------------
>  include/kvm/arm_psci.h | 27 +++++++++++++++++++++++++++
>  2 files changed, 28 insertions(+), 29 deletions(-)
> 
> diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
> index 3b5dbe9a0a0e..e3db84400d1f 100644
> --- a/arch/arm64/kvm/psci.c
> +++ b/arch/arm64/kvm/psci.c
> @@ -21,16 +21,6 @@
>   * as described in ARM document number ARM DEN 0022A.
>   */
>  
> -#define AFFINITY_MASK(level)	~((0x1UL << ((level) * MPIDR_LEVEL_BITS)) - 1)
> -
> -static unsigned long psci_affinity_mask(unsigned long affinity_level)
> -{
> -	if (affinity_level <= 3)
> -		return MPIDR_HWID_BITMASK & AFFINITY_MASK(affinity_level);
> -
> -	return 0;
> -}
> -
>  static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
>  {
>  	/*
> @@ -51,12 +41,6 @@ static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
>  	return PSCI_RET_SUCCESS;
>  }
>  
> -static inline bool kvm_psci_valid_affinity(struct kvm_vcpu *vcpu,
> -					   unsigned long affinity)
> -{
> -	return !(affinity & ~MPIDR_HWID_BITMASK);
> -}
> -
>  static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
>  {
>  	struct vcpu_reset_state *reset_state;
> @@ -135,7 +119,7 @@ static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
>  		return PSCI_RET_INVALID_PARAMS;
>  
>  	/* Determine target affinity mask */
> -	target_affinity_mask = psci_affinity_mask(lowest_affinity_level);
> +	target_affinity_mask = kvm_psci_affinity_mask(lowest_affinity_level);
>  	if (!target_affinity_mask)
>  		return PSCI_RET_INVALID_PARAMS;
>  
> @@ -220,18 +204,6 @@ static void kvm_psci_system_suspend(struct kvm_vcpu *vcpu)
>  	run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
>  }
>  
> -static void kvm_psci_narrow_to_32bit(struct kvm_vcpu *vcpu)
> -{
> -	int i;
> -
> -	/*
> -	 * Zero the input registers' upper 32 bits. They will be fully
> -	 * zeroed on exit, so we're fine changing them in place.
> -	 */
> -	for (i = 1; i < 4; i++)
> -		vcpu_set_reg(vcpu, i, lower_32_bits(vcpu_get_reg(vcpu, i)));
> -}
> -
>  static unsigned long kvm_psci_check_allowed_function(struct kvm_vcpu *vcpu, u32 fn)
>  {
>  	/*
> diff --git a/include/kvm/arm_psci.h b/include/kvm/arm_psci.h
> index cbaec804eb83..f86a006d6713 100644
> --- a/include/kvm/arm_psci.h
> +++ b/include/kvm/arm_psci.h
> @@ -38,6 +38,33 @@ static inline int kvm_psci_version(struct kvm_vcpu *vcpu)
>  	return KVM_ARM_PSCI_0_1;
>  }
>  
> +/* Narrow the PSCI register arguments (r1 to r3) to 32 bits. */
> +static inline void kvm_psci_narrow_to_32bit(struct kvm_vcpu *vcpu)
> +{
> +	int i;
> +
> +	/*
> +	 * Zero the input registers' upper 32 bits. They will be fully
> +	 * zeroed on exit, so we're fine changing them in place.
> +	 */
> +	for (i = 1; i < 4; i++)
> +		vcpu_set_reg(vcpu, i, lower_32_bits(vcpu_get_reg(vcpu, i)));
> +}
> +
> +static inline bool kvm_psci_valid_affinity(struct kvm_vcpu *vcpu,
> +					   unsigned long affinity)
> +{
> +	return !(affinity & ~MPIDR_HWID_BITMASK);
> +}
> +
> +static inline unsigned long kvm_psci_affinity_mask(unsigned long affinity_level)
> +{
> +	if (affinity_level <= 3)
> +		return MPIDR_HWID_BITMASK &
> +			~((0x1UL << (affinity_level * MPIDR_LEVEL_BITS)) - 1);
> +
> +	return 0;
> +}
>  
>  int kvm_psci_call(struct kvm_vcpu *vcpu);
>  
> -- 
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>