KVM: arm/arm64: vgic: Define GICD_IIDR fields for GICv2 and GIv3

Instead of hardcoding the shifts and masks in the GICD_IIDR register
emulation, let's add the definition of these fields to the GIC header
files and use them.

This will make things more obvious when we're going to bump the revision
in the IIDR when we'll make guest-visible changes to the implementation.

Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

include/linux/irqchip/arm-gic-v3.h

@@ -61,6 +61,16 @@
 #define GICD_CTLR_ENABLE_G1A		(1U << 1)
 #define GICD_CTLR_ENABLE_G1		(1U << 0)
 
+#define GICD_IIDR_IMPLEMENTER_SHIFT	0
+#define GICD_IIDR_IMPLEMENTER_MASK	(0xfff << GICD_IIDR_IMPLEMENTER_SHIFT)
+#define GICD_IIDR_REVISION_SHIFT	12
+#define GICD_IIDR_REVISION_MASK		(0xf << GICD_IIDR_REVISION_SHIFT)
+#define GICD_IIDR_VARIANT_SHIFT		16
+#define GICD_IIDR_VARIANT_MASK		(0xf << GICD_IIDR_VARIANT_SHIFT)
+#define GICD_IIDR_PRODUCT_ID_SHIFT	24
+#define GICD_IIDR_PRODUCT_ID_MASK	(0xff << GICD_IIDR_PRODUCT_ID_SHIFT)
+
+
 /*
  * In systems with a single security state (what we emulate in KVM)
  * the meaning of the interrupt group enable bits is slightly different

include/linux/irqchip/arm-gic.h

@@ -71,6 +71,16 @@
 					(GICD_INT_DEF_PRI << 8) |\
 					GICD_INT_DEF_PRI)
 
+#define GICD_IIDR_IMPLEMENTER_SHIFT	0
+#define GICD_IIDR_IMPLEMENTER_MASK	(0xfff << GICD_IIDR_IMPLEMENTER_SHIFT)
+#define GICD_IIDR_REVISION_SHIFT	12
+#define GICD_IIDR_REVISION_MASK		(0xf << GICD_IIDR_REVISION_SHIFT)
+#define GICD_IIDR_VARIANT_SHIFT		16
+#define GICD_IIDR_VARIANT_MASK		(0xf << GICD_IIDR_VARIANT_SHIFT)
+#define GICD_IIDR_PRODUCT_ID_SHIFT	24
+#define GICD_IIDR_PRODUCT_ID_MASK	(0xff << GICD_IIDR_PRODUCT_ID_SHIFT)
+
+
 #define GICH_HCR			0x0
 #define GICH_VTR			0x4
 #define GICH_VMCR			0x8

virt/kvm/arm/vgic/vgic-mmio-v2.c

@@ -37,7 +37,8 @@ static unsigned long vgic_mmio_read_v2_misc(struct kvm_vcpu *vcpu,
 		value |= (atomic_read(&vcpu->kvm->online_vcpus) - 1) << 5;
 		break;
 	case GIC_DIST_IIDR:
-		value = (PRODUCT_ID_KVM << 24) | (IMPLEMENTER_ARM << 0);
+		value = (PRODUCT_ID_KVM << GICD_IIDR_PRODUCT_ID_SHIFT) |
+			(IMPLEMENTER_ARM << GICD_IIDR_IMPLEMENTER_SHIFT);
 		break;
 	default:
 		return 0;

virt/kvm/arm/vgic/vgic-mmio-v3.c

@@ -81,7 +81,8 @@ static unsigned long vgic_mmio_read_v3_misc(struct kvm_vcpu *vcpu,
 		}
 		break;
 	case GICD_IIDR:
-		value = (PRODUCT_ID_KVM << 24) | (IMPLEMENTER_ARM << 0);
+		value = (PRODUCT_ID_KVM << GICD_IIDR_PRODUCT_ID_SHIFT) |
+			(IMPLEMENTER_ARM << GICD_IIDR_IMPLEMENTER_SHIFT);
 		break;
 	default:
 		return 0;