Re: [PATCH v3 39/59] KVM: arm/arm64: GICv4: Add property field and per-VM predicate

Christoffer Dall
2017-08-26T19:49:15Z

On Mon, Jul 31, 2017 at 06:26:17PM +0100, Marc Zyngier wrote:
> Add a new has_gicv4 field in the global VGIC state that indicates
> whether the HW is GICv4 capable, as a per-VM predicate indicating
> if there is a possibility for a VM to support direct injection
> (the above being true and the VM having an ITS).
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> include/kvm/arm_vgic.h | 3 +++
> virt/kvm/arm/vgic/vgic-mmio-v3.c | 5 +++++
> virt/kvm/arm/vgic/vgic.h | 2 ++
> 3 files changed, 10 insertions(+)
>
> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> index ee8587c8c715..84694b42373a 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -73,6 +73,9 @@ struct vgic_global {
> /* Only needed for the legacy KVM_CREATE_IRQCHIP */
> bool can_emulate_gicv2;
>
> + /* Does have GICv4? */

nit: questionable comment, how about

/* Hardware has GICv4? */
or
/* Do we have GICv4? */

> + bool has_gicv4;
> +
> /* GIC system register CPU interface */
> struct static_key_false gicv3_cpuif;
>
> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> index 714fa3933546..74109ca75cc0 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> @@ -54,6 +54,11 @@ bool vgic_has_its(struct kvm *kvm)
> return dist->has_its;
> }
>
> +bool vgic_is_v4_capable(struct kvm *kvm)
> +{
> + return kvm_vgic_global_state.has_gicv4 && vgic_has_its(kvm);
> +}
> +

uber nit: the naming here is a bit funny, because we won't be presenting
a GICv4 GIC to the guest, so I'd prefer something like
vgic_supports_direct_msis() or something like that, but this is
obviously not a deal breaker.

> static unsigned long vgic_mmio_read_v3_misc(struct kvm_vcpu *vcpu,
> gpa_t addr, unsigned int len)
> {
> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
> index 3002b72d938b..90f6436a11aa 100644
> --- a/virt/kvm/arm/vgic/vgic.h
> +++ b/virt/kvm/arm/vgic/vgic.h
> @@ -229,4 +229,6 @@ int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its,
> u32 devid, u32 eventid, struct vgic_irq **irq);
> struct vgic_its *vgic_msi_to_its(struct kvm *kvm, struct kvm_msi *msi);
>
> +bool vgic_is_v4_capable(struct kvm *kvm);
> +
> #endif
> --
> 2.11.0
>

Thanks,
-Christoffer