diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c
index f4fdf351a7c7..1a8de57289eb 100644
--- a/drivers/lguest/lguest_device.c
+++ b/drivers/lguest/lguest_device.c
@@ -20,9 +20,6 @@
 /* The pointer to our (page) of device descriptions. */
 static void *lguest_devices;
 
-/* Unique numbering for lguest devices. */
-static unsigned int dev_index;
-
 /* For Guests, device memory can be used as normal memory, so we cast away the
  * __iomem to quieten sparse. */
 static inline void *lguest_map(unsigned long phys_addr, unsigned long pages)
@@ -325,8 +322,10 @@ static struct device lguest_root = {
  * As Andrew Tridgell says, "Untested code is buggy code".
  *
  * It's worth reading this carefully: we start with a pointer to the new device
- * descriptor in the "lguest_devices" page. */
-static void add_lguest_device(struct lguest_device_desc *d)
+ * descriptor in the "lguest_devices" page, and the offset into the device
+ * descriptor page so we can uniquely identify it if things go badly wrong. */
+static void add_lguest_device(struct lguest_device_desc *d,
+			      unsigned int offset)
 {
 	struct lguest_device *ldev;
 
@@ -334,18 +333,14 @@ static void add_lguest_device(struct lguest_device_desc *d)
 	 * it. */
 	ldev = kzalloc(sizeof(*ldev), GFP_KERNEL);
 	if (!ldev) {
-		printk(KERN_EMERG "Cannot allocate lguest dev %u\n",
-		       dev_index++);
+		printk(KERN_EMERG "Cannot allocate lguest dev %u type %u\n",
+		       offset, d->type);
 		return;
 	}
 
 	/* This devices' parent is the lguest/ dir. */
 	ldev->vdev.dev.parent = &lguest_root;
 	/* We have a unique device index thanks to the dev_index counter. */
-	ldev->vdev.index = dev_index++;
-	/* The device type comes straight from the descriptor.  There's also a
-	 * device vendor field in the virtio_device struct, which we leave as
-	 * 0. */
 	ldev->vdev.id.device = d->type;
 	/* We have a simple set of routines for querying the device's
 	 * configuration information and setting its status. */
@@ -357,8 +352,8 @@ static void add_lguest_device(struct lguest_device_desc *d)
 	 * virtio_device and calls device_register().  This makes the bus
 	 * infrastructure look for a matching driver. */
 	if (register_virtio_device(&ldev->vdev) != 0) {
-		printk(KERN_ERR "Failed to register lguest device %u\n",
-		       ldev->vdev.index);
+		printk(KERN_ERR "Failed to register lguest dev %u type %u\n",
+		       offset, d->type);
 		kfree(ldev);
 	}
 }
@@ -379,7 +374,7 @@ static void scan_devices(void)
 			break;
 
 		printk("Device at %i has size %u\n", i, desc_size(d));
-		add_lguest_device(d);
+		add_lguest_device(d, i);
 	}
 }
 
diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
index 9f55ce6f3c78..5ab34340919b 100644
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -31,11 +31,6 @@
  */
 static void *kvm_devices;
 
-/*
- * Unique numbering for kvm devices.
- */
-static unsigned int dev_index;
-
 struct kvm_device {
 	struct virtio_device vdev;
 	struct kvm_device_desc *desc;
@@ -250,26 +245,25 @@ static struct device kvm_root = {
  * adds a new device and register it with virtio
  * appropriate drivers are loaded by the device model
  */
-static void add_kvm_device(struct kvm_device_desc *d)
+static void add_kvm_device(struct kvm_device_desc *d, unsigned int offset)
 {
 	struct kvm_device *kdev;
 
 	kdev = kzalloc(sizeof(*kdev), GFP_KERNEL);
 	if (!kdev) {
-		printk(KERN_EMERG "Cannot allocate kvm dev %u\n",
-		       dev_index++);
+		printk(KERN_EMERG "Cannot allocate kvm dev %u type %u\n",
+		       offset, d->type);
 		return;
 	}
 
 	kdev->vdev.dev.parent = &kvm_root;
-	kdev->vdev.index = dev_index++;
 	kdev->vdev.id.device = d->type;
 	kdev->vdev.config = &kvm_vq_configspace_ops;
 	kdev->desc = d;
 
 	if (register_virtio_device(&kdev->vdev) != 0) {
-		printk(KERN_ERR "Failed to register kvm device %u\n",
-		       kdev->vdev.index);
+		printk(KERN_ERR "Failed to register kvm device %u type %u\n",
+		       offset, d->type);
 		kfree(kdev);
 	}
 }
@@ -289,7 +283,7 @@ static void scan_devices(void)
 		if (d->type == 0)
 			break;
 
-		add_kvm_device(d);
+		add_kvm_device(d, i);
 	}
 }
 
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 59918dfc3cb7..0f3c2bb7bf35 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -2,6 +2,9 @@
 #include <linux/spinlock.h>
 #include <linux/virtio_config.h>
 
+/* Unique numbering for virtio devices. */
+static unsigned int dev_index;
+
 static ssize_t device_show(struct device *_d,
 			   struct device_attribute *attr, char *buf)
 {
@@ -166,6 +169,9 @@ int register_virtio_device(struct virtio_device *dev)
 	int err;
 
 	dev->dev.bus = &virtio_bus;
+
+	/* Assign a unique device index and hence name. */
+	dev->index = dev_index++;
 	sprintf(dev->dev.bus_id, "virtio%u", dev->index);
 
 	/* We always start by resetting the device, in case a previous
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index 2913c2f309f0..eae7236310e4 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -78,9 +78,6 @@ static struct device virtio_pci_root = {
 	.bus_id		= "virtio-pci",
 };
 
-/* Unique numbering for devices under the kvm root */
-static unsigned int dev_index;
-
 /* Convert a generic virtio device to our structure */
 static struct virtio_pci_device *to_vp_device(struct virtio_device *vdev)
 {
@@ -325,9 +322,6 @@ static int __devinit virtio_pci_probe(struct pci_dev *pci_dev,
 	if (vp_dev == NULL)
 		return -ENOMEM;
 
-	vp_dev->vdev.index = dev_index;
-	dev_index++;
-
 	vp_dev->vdev.dev.parent = &virtio_pci_root;
 	vp_dev->vdev.config = &virtio_pci_config_ops;
 	vp_dev->pci_dev = pci_dev;