Re: [PATCH v8 3/8] KVM: arm64: Make a helper function to get nr of timer regs

[Andrew Jones <drjones@redhat.com>]

On Thu, Sep 16, 2021 at 06:15:05PM +0000, Oliver Upton wrote:
> Presently, the number of timer registers is constant. There may be
> opt-in behavior in KVM that exposes more timer registers to userspace.
> Prepare for the change by switching from a macro to a helper function to
> get the number of timer registers.
> 
> No functional change intended.
> 
> Signed-off-by: Oliver Upton <oupton@google.com>
> ---
>  arch/arm64/kvm/guest.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
> index 5ce26bedf23c..a13a79f5e0e2 100644
> --- a/arch/arm64/kvm/guest.c
> +++ b/arch/arm64/kvm/guest.c
> @@ -588,7 +588,10 @@ static unsigned long num_core_regs(const struct kvm_vcpu *vcpu)
>   * ARM64 versions of the TIMER registers, always available on arm64
>   */
>  
> -#define NUM_TIMER_REGS 3
> +static inline unsigned long num_timer_regs(struct kvm_vcpu *vcpu)
> +{
> +	return 3;
> +}
>  
>  static bool is_timer_reg(u64 index)
>  {
> @@ -711,7 +714,7 @@ unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu)
>  	res += num_sve_regs(vcpu);
>  	res += kvm_arm_num_sys_reg_descs(vcpu);
>  	res += kvm_arm_get_fw_num_regs(vcpu);
> -	res += NUM_TIMER_REGS;
> +	res += num_timer_regs(vcpu);
>  
>  	return res;
>  }
> @@ -743,7 +746,7 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
>  	ret = copy_timer_indices(vcpu, uindices);
>  	if (ret < 0)
>  		return ret;
> -	uindices += NUM_TIMER_REGS;
> +	uindices += num_timer_regs(vcpu);
>  
>  	return kvm_arm_copy_sys_reg_indices(vcpu, uindices);
>  }
> -- 
> 2.33.0.309.g3052b89438-goog
>

Reviewed-by: Andrew Jones <drjones@redhat.com>