ARM: KVM: vgic: simplify vgic_get_target_reg

vgic_get_target_reg is quite complicated, for no good reason.
Actually, it is fairly easy to write it in a much more efficient
way by using the target CPU array instead of the bitmap.
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

virt/kvm/arm/vgic.c

@@ -432,19 +432,13 @@ static bool handle_mmio_priority_reg(struct kvm_vcpu *vcpu,
 static u32 vgic_get_target_reg(struct kvm *kvm, int irq)
 {
 	struct vgic_dist *dist = &kvm->arch.vgic;
-	struct kvm_vcpu *vcpu;
-	int i, c;
-	unsigned long *bmap;
+	int i;
 	u32 val = 0;
 
 	irq -= VGIC_NR_PRIVATE_IRQS;
 
-	kvm_for_each_vcpu(c, vcpu, kvm) {
-		bmap = vgic_bitmap_get_shared_map(&dist->irq_spi_target[c]);
 	for (i = 0; i < GICD_IRQS_PER_ITARGETSR; i++)
-			if (test_bit(irq + i, bmap))
-				val |= 1 << (c + i * 8);
-	}
+		val |= 1 << (dist->irq_spi_cpu[irq + i] + i * 8);
 
 	return val;
 }