Re: [PATCH 07/31] KVM: arm/arm64: vgic-v3: Add accessors for the ICH_APxRn_EL2 registers

Mark Rutland
2017-05-03T15:32:01Z

On Wed, May 03, 2017 at 11:45:42AM +0100, Marc Zyngier wrote:
> As we're about to access the Active Priority registers a lot more,
> let's define accessors that take the register number as a parameter.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> virt/kvm/arm/hyp/vgic-v3-sr.c | 116 ++++++++++++++++++++++++++++++++++++------
> 1 file changed, 100 insertions(+), 16 deletions(-)
>
> diff --git a/virt/kvm/arm/hyp/vgic-v3-sr.c b/virt/kvm/arm/hyp/vgic-v3-sr.c
> index 32c3295929b0..990d9d1e85d0 100644
> --- a/virt/kvm/arm/hyp/vgic-v3-sr.c
> +++ b/virt/kvm/arm/hyp/vgic-v3-sr.c
> @@ -118,6 +118,90 @@ static void __hyp_text __gic_v3_set_lr(u64 val, int lr)
> }
> }
>
> +static void __hyp_text __vgic_v3_write_ap0rn(u32 val, int n)
> +{
> + switch (n) {
> + case 0:
> + write_gicreg(val, ICH_AP0R0_EL2);
> + break;
> + case 1:
> + write_gicreg(val, ICH_AP0R1_EL2);
> + break;
> + case 2:
> + write_gicreg(val, ICH_AP0R2_EL2);
> + break;
> + case 3:
> + write_gicreg(val, ICH_AP0R3_EL2);
> + break;
> + }

Is there any way we can get a build or runtime failure for an
out-of-bounds n value?

> +}

Given this is used with a constant n, you could make this:

#define __vgic_v3_write_ap0rn(v, n) \
write_gicreg(v, ICH_AP0R##n##_EL2)

... which should also give you a warning for an out-of-bounds n.

Similar could apply for the other helpers here.

That would require some function -> macro conversion in later patches
though, so I can understand if you're not keen on that.

Thanks,
Mark.