diff --git a/devices.c b/devices.c
index 5b627e9..b560a59 100644
--- a/devices.c
+++ b/devices.c
@@ -1,5 +1,7 @@
 #include "kvm/devices.h"
 #include "kvm/kvm.h"
+#include "kvm/pci.h"
+#include "kvm/virtio-mmio.h"
 
 #include <linux/err.h>
 #include <linux/rbtree.h>
@@ -27,6 +29,17 @@ int device__register(struct device_header *dev)
 	bus = &device_trees[dev->bus_type];
 	dev->dev_num = bus->dev_num++;
 
+	switch (dev->bus_type) {
+	case DEVICE_BUS_PCI:
+		pci__assign_irq(dev);
+		break;
+	case DEVICE_BUS_MMIO:
+		virtio_mmio_assign_irq(dev);
+		break;
+	default:
+		break;
+	}
+
 	node = &bus->root.rb_node;
 	while (*node) {
 		int num = rb_entry(*node, struct device_header, node)->dev_num;
diff --git a/hw/pci-shmem.c b/hw/pci-shmem.c
index 0571183..34de747 100644
--- a/hw/pci-shmem.c
+++ b/hw/pci-shmem.c
@@ -358,10 +358,6 @@ int pci_shmem__init(struct kvm *kvm)
 	if (shmem_region == NULL)
 		return 0;
 
-	/* Register good old INTx */
-	pci_shmem_pci_device.irq_pin = 1;
-	pci_shmem_pci_device.irq_line = irq__alloc_line();
-
 	/* Register MMIO space for MSI-X */
 	r = ioport__register(kvm, IOPORT_EMPTY, &shmem_pci__io_ops, IOPORT_SIZE, NULL);
 	if (r < 0)
diff --git a/hw/vesa.c b/hw/vesa.c
index c7b8e66..a0b15a7 100644
--- a/hw/vesa.c
+++ b/hw/vesa.c
@@ -65,8 +65,6 @@ struct framebuffer *vesa__init(struct kvm *kvm)
 	if (r < 0)
 		return ERR_PTR(r);
 
-	vesa_pci_device.irq_pin		= 1;
-	vesa_pci_device.irq_line	= irq__alloc_line();
 	vesa_base_addr			= (u16)r;
 	vesa_pci_device.bar[0]		= cpu_to_le32(vesa_base_addr | PCI_BASE_ADDRESS_SPACE_IO);
 	device__register(&vesa_device);
diff --git a/include/kvm/pci.h b/include/kvm/pci.h
index e1e621d..b0c28a1 100644
--- a/include/kvm/pci.h
+++ b/include/kvm/pci.h
@@ -6,6 +6,7 @@
 #include <linux/pci_regs.h>
 #include <endian.h>
 
+#include "kvm/devices.h"
 #include "kvm/kvm.h"
 #include "kvm/msi.h"
 
@@ -88,6 +89,7 @@ int pci__init(struct kvm *kvm);
 int pci__exit(struct kvm *kvm);
 struct pci_device_header *pci__find_dev(u8 dev_num);
 u32 pci_get_io_space_block(u32 size);
+void pci__assign_irq(struct device_header *dev_hdr);
 void pci__config_wr(struct kvm *kvm, union pci_config_address addr, void *data, int size);
 void pci__config_rd(struct kvm *kvm, union pci_config_address addr, void *data, int size);
 
diff --git a/include/kvm/virtio-mmio.h b/include/kvm/virtio-mmio.h
index 4d6a671..835f421 100644
--- a/include/kvm/virtio-mmio.h
+++ b/include/kvm/virtio-mmio.h
@@ -56,4 +56,5 @@ int virtio_mmio_signal_config(struct kvm *kvm, struct virtio_device *vdev);
 int virtio_mmio_exit(struct kvm *kvm, struct virtio_device *vdev);
 int virtio_mmio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
 		      int device_id, int subsys_id, int class);
+void virtio_mmio_assign_irq(struct device_header *dev_hdr);
 #endif
diff --git a/pci.c b/pci.c
index c4442c8..c2da152 100644
--- a/pci.c
+++ b/pci.c
@@ -1,6 +1,7 @@
 #include "kvm/devices.h"
 #include "kvm/pci.h"
 #include "kvm/ioport.h"
+#include "kvm/irq.h"
 #include "kvm/util.h"
 #include "kvm/kvm.h"
 
@@ -28,6 +29,20 @@ u32 pci_get_io_space_block(u32 size)
 	return block;
 }
 
+void pci__assign_irq(struct device_header *dev_hdr)
+{
+	struct pci_device_header *pci_hdr = dev_hdr->data;
+
+	/*
+	 * PCI supports only INTA#,B#,C#,D# per device.
+	 *
+	 * A#,B#,C#,D# are allowed for multifunctional devices so stick
+	 * with A# for our single function devices.
+	 */
+	pci_hdr->irq_pin	= 1;
+	pci_hdr->irq_line	= irq__alloc_line();
+}
+
 static void *pci_config_address_ptr(u16 port)
 {
 	unsigned long offset;
diff --git a/virtio/mmio.c b/virtio/mmio.c
index 1cb186b..e1fca2b 100644
--- a/virtio/mmio.c
+++ b/virtio/mmio.c
@@ -256,6 +256,14 @@ static void generate_virtio_mmio_fdt_node(void *fdt,
 }
 #endif
 
+void virtio_mmio_assign_irq(struct device_header *dev_hdr)
+{
+	struct virtio_mmio *vmmio = container_of(dev_hdr,
+						 struct virtio_mmio,
+						 dev_hdr);
+	vmmio->irq = irq__alloc_line();
+}
+
 int virtio_mmio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
 		     int device_id, int subsys_id, int class)
 {
@@ -276,7 +284,6 @@ int virtio_mmio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
 		.queue_num_max	= 256,
 	};
 
-	vmmio->irq = irq__alloc_line();
 	vmmio->dev_hdr = (struct device_header) {
 		.bus_type	= DEVICE_BUS_MMIO,
 		.data		= generate_virtio_mmio_fdt_node,
diff --git a/virtio/pci.c b/virtio/pci.c
index dbd6758..fa7aa00 100644
--- a/virtio/pci.c
+++ b/virtio/pci.c
@@ -408,8 +408,6 @@ int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
 	if (kvm__supports_extension(kvm, KVM_CAP_SIGNAL_MSI))
 		vpci->features |= VIRTIO_PCI_F_SIGNAL_MSI;
 
-	vpci->pci_hdr.irq_pin	= 1;
-	vpci->pci_hdr.irq_line	= irq__alloc_line();
 	r = device__register(&vpci->dev_hdr);
 	if (r < 0)
 		goto free_msix_mmio;