KVM: arm/arm64: GICv4: Add property field and per-VM predicate

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).

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

include/kvm/arm_vgic.h

@@ -73,6 +73,9 @@ struct vgic_global {
 	/* Only needed for the legacy KVM_CREATE_IRQCHIP */
 	bool			can_emulate_gicv2;
 
+	/* Hardware has GICv4? */
+	bool			has_gicv4;
+
 	/* GIC system register CPU interface */
 	struct static_key_false gicv3_cpuif;
 

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_supports_direct_msis(struct kvm *kvm)
+{
+	return kvm_vgic_global_state.has_gicv4 && vgic_has_its(kvm);
+}
+
 static unsigned long vgic_mmio_read_v3_misc(struct kvm_vcpu *vcpu,
 					    gpa_t addr, unsigned int len)
 {

virt/kvm/arm/vgic/vgic.h

@@ -241,4 +241,6 @@ 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_supports_direct_msis(struct kvm *kvm);
+
 #endif