arm/arm64: KVM: Only allow 64bit hosts to build VGICv3

Hardware virtualisation of GICv3 is only supported by 64bit hosts for
the moment. Some VGICv3 bits are missing from the 32bit side, and this
patch allows to still be able to build 32bit hosts when CONFIG_ARM_GIC_V3
is selected.

To this end, we introduce a new option, CONFIG_KVM_ARM_VGIC_V3, that is
only enabled on the 64bit side. The selection is done unconditionally
because CONFIG_ARM_GIC_V3 is always enabled on arm64.
Reviewed-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NJean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

arch/arm64/kvm/Kconfig

@@ -16,6 +16,9 @@ menuconfig VIRTUALIZATION
 
 if VIRTUALIZATION
 
+config KVM_ARM_VGIC_V3
+	bool
+
 config KVM
 	bool "Kernel-based Virtual Machine (KVM) support"
 	depends on OF
@@ -31,6 +34,7 @@ config KVM
 	select KVM_VFIO
 	select HAVE_KVM_EVENTFD
 	select HAVE_KVM_IRQFD
+	select KVM_ARM_VGIC_V3
 	---help---
 	  Support hosting virtualized guest machines.
 

include/kvm/arm_vgic.h

@@ -282,7 +282,7 @@ struct vgic_v2_cpu_if {
 };
 
 struct vgic_v3_cpu_if {
-#ifdef CONFIG_ARM_GIC_V3
+#ifdef CONFIG_KVM_ARM_VGIC_V3
 	u32		vgic_hcr;
 	u32		vgic_vmcr;
 	u32		vgic_sre;	/* Restored only, change ignored */
@@ -364,7 +364,7 @@ void kvm_vgic_set_phys_irq_active(struct irq_phys_map *map, bool active);
 int vgic_v2_probe(struct device_node *vgic_node,
 		  const struct vgic_ops **ops,
 		  const struct vgic_params **params);
-#ifdef CONFIG_ARM_GIC_V3
+#ifdef CONFIG_KVM_ARM_VGIC_V3
 int vgic_v3_probe(struct device_node *vgic_node,
 		  const struct vgic_ops **ops,
 		  const struct vgic_params **params);

virt/kvm/arm/vgic.c

@@ -2122,7 +2122,7 @@ static int init_vgic_model(struct kvm *kvm, int type)
 	case KVM_DEV_TYPE_ARM_VGIC_V2:
 		vgic_v2_init_emulation(kvm);
 		break;
-#ifdef CONFIG_ARM_GIC_V3
+#ifdef CONFIG_KVM_ARM_VGIC_V3
 	case KVM_DEV_TYPE_ARM_VGIC_V3:
 		vgic_v3_init_emulation(kvm);
 		break;
@@ -2284,7 +2284,7 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
 		block_size = KVM_VGIC_V2_CPU_SIZE;
 		alignment = SZ_4K;
 		break;
-#ifdef CONFIG_ARM_GIC_V3
+#ifdef CONFIG_KVM_ARM_VGIC_V3
 	case KVM_VGIC_V3_ADDR_TYPE_DIST:
 		type_needed = KVM_DEV_TYPE_ARM_VGIC_V3;
 		addr_ptr = &vgic->vgic_dist_base;