[PATCH 3/5] KVM: arm64: Fast-track kvm_mpidr_to_vcpu() when mpidr_data is available

[Joey Gouly]

On Thu, Sep 07, 2023 at 11:09:29AM +0100, Marc Zyngier wrote:
> If our fancy little table is present when calling kvm_mpidr_to_vcpu(),
> use it to recover the corresponding vcpu.
> 
> Signed-off-by: Marc Zyngier <maz at kernel.org>
> ---
>  arch/arm64/kvm/arm.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 30ce394c09d4..5b75b2db12be 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -2395,6 +2395,18 @@ struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr)
>  	unsigned long i;
>  
>  	mpidr &= MPIDR_HWID_BITMASK;
> +
> +	if (kvm->arch.mpidr_data) {
> +		u16 idx = kvm_mpidr_index(kvm->arch.mpidr_data, mpidr);
> +
> +		vcpu = kvm_get_vcpu(kvm,
> +				    kvm->arch.mpidr_data->cmpidr_to_idx[idx]);
> +		if (mpidr != kvm_vcpu_get_mpidr_aff(vcpu))
> +			vcpu = NULL;
> +
> +		return vcpu;
> +	}
> +
>  	kvm_for_each_vcpu(i, vcpu, kvm) {
>  		if (mpidr == kvm_vcpu_get_mpidr_aff(vcpu))
>  			return vcpu;

Reviewed-by: Joey Gouly <joey.gouly at arm.com>