diff --git a/hw/usb/desc.c b/hw/usb/desc.c
index 3c77368cb0..e8a3c6af3d 100644
--- a/hw/usb/desc.c
+++ b/hw/usb/desc.c
@@ -1,3 +1,5 @@
+#include <ctype.h>
+
 #include "hw/usb.h"
 #include "hw/usb/desc.h"
 #include "trace.h"
@@ -412,6 +414,36 @@ void usb_desc_set_string(USBDevice *dev, uint8_t index, const char *str)
     s->str = g_strdup(str);
 }
 
+/*
+ * This function creates a serial number for a usb device.
+ * The serial number should:
+ *   (a) Be unique within the virtual machine.
+ *   (b) Be constant, so you don't get a new one each
+ *       time the guest is started.
+ * So we are using the physical location to generate a serial number
+ * from it.  It has three pieces:  First a fixed, device-specific
+ * prefix.  Second the device path of the host controller (which is
+ * the pci address in most cases).  Third the physical port path.
+ * Results in serial numbers like this: "314159-0000:00:1d.7-3".
+ */
+void usb_desc_create_serial(USBDevice *dev)
+{
+    DeviceState *hcd = dev->qdev.parent_bus->parent;
+    const USBDesc *desc = usb_device_get_usb_desc(dev);
+    int index = desc->id.iSerialNumber;
+    char serial[64];
+    int dst;
+
+    assert(index != 0 && desc->str[index] != NULL);
+    dst = snprintf(serial, sizeof(serial), "%s", desc->str[index]);
+    if (hcd && hcd->parent_bus && hcd->parent_bus->info->get_dev_path) {
+        char *path = hcd->parent_bus->info->get_dev_path(hcd);
+        dst += snprintf(serial+dst, sizeof(serial)-dst, "-%s", path);
+    }
+    dst += snprintf(serial+dst, sizeof(serial)-dst, "-%s", dev->port->path);
+    usb_desc_set_string(dev, index, serial);
+}
+
 const char *usb_desc_get_string(USBDevice *dev, uint8_t index)
 {
     USBDescString *s;
diff --git a/hw/usb/desc.h b/hw/usb/desc.h
index d164e8f891..7cf5442945 100644
--- a/hw/usb/desc.h
+++ b/hw/usb/desc.h
@@ -171,6 +171,7 @@ int usb_desc_other(const USBDescOther *desc, uint8_t *dest, size_t len);
 void usb_desc_init(USBDevice *dev);
 void usb_desc_attach(USBDevice *dev);
 void usb_desc_set_string(USBDevice *dev, uint8_t index, const char *str);
+void usb_desc_create_serial(USBDevice *dev);
 const char *usb_desc_get_string(USBDevice *dev, uint8_t index);
 int usb_desc_string(USBDevice *dev, int index, uint8_t *dest, size_t len);
 int usb_desc_get_descriptor(USBDevice *dev, int value, uint8_t *dest, size_t len);
diff --git a/hw/usb/dev-audio.c b/hw/usb/dev-audio.c
index 426b95c82b..79b75fb628 100644
--- a/hw/usb/dev-audio.c
+++ b/hw/usb/dev-audio.c
@@ -648,6 +648,7 @@ static int usb_audio_initfn(USBDevice *dev)
 {
     USBAudioState *s = DO_UPCAST(USBAudioState, dev, dev);
 
+    usb_desc_create_serial(dev);
     usb_desc_init(dev);
     s->dev.opaque = s;
     AUD_register_card("usb-audio", &s->card);
diff --git a/hw/usb/dev-bluetooth.c b/hw/usb/dev-bluetooth.c
index 195370c24a..6b74eff4ad 100644
--- a/hw/usb/dev-bluetooth.c
+++ b/hw/usb/dev-bluetooth.c
@@ -494,6 +494,7 @@ static void usb_bt_handle_destroy(USBDevice *dev)
 
 static int usb_bt_initfn(USBDevice *dev)
 {
+    usb_desc_create_serial(dev);
     usb_desc_init(dev);
     return 0;
 }
diff --git a/hw/usb/dev-hub.c b/hw/usb/dev-hub.c
index 9c9166551e..b5962da72a 100644
--- a/hw/usb/dev-hub.c
+++ b/hw/usb/dev-hub.c
@@ -520,6 +520,7 @@ static int usb_hub_initfn(USBDevice *dev)
     USBHubPort *port;
     int i;
 
+    usb_desc_create_serial(dev);
     usb_desc_init(dev);
     s->intr = usb_ep_get(dev, USB_TOKEN_IN, 1);
     for (i = 0; i < NUM_PORTS; i++) {
diff --git a/hw/usb/dev-network.c b/hw/usb/dev-network.c
index cff55f223e..b238a0973d 100644
--- a/hw/usb/dev-network.c
+++ b/hw/usb/dev-network.c
@@ -1324,6 +1324,7 @@ static int usb_net_initfn(USBDevice *dev)
 {
     USBNetState *s = DO_UPCAST(USBNetState, dev, dev);
 
+    usb_desc_create_serial(dev);
     usb_desc_init(dev);
 
     s->rndis_state = RNDIS_UNINITIALIZED;
diff --git a/hw/usb/dev-serial.c b/hw/usb/dev-serial.c
index 8dcac8bc88..56743ee020 100644
--- a/hw/usb/dev-serial.c
+++ b/hw/usb/dev-serial.c
@@ -479,6 +479,7 @@ static int usb_serial_initfn(USBDevice *dev)
 {
     USBSerialState *s = DO_UPCAST(USBSerialState, dev, dev);
 
+    usb_desc_create_serial(dev);
     usb_desc_init(dev);
 
     if (!s->cs) {
diff --git a/hw/usb/dev-smartcard-reader.c b/hw/usb/dev-smartcard-reader.c
index 8e66675d86..3b7604e8b1 100644
--- a/hw/usb/dev-smartcard-reader.c
+++ b/hw/usb/dev-smartcard-reader.c
@@ -1189,6 +1189,7 @@ static int ccid_initfn(USBDevice *dev)
 {
     USBCCIDState *s = DO_UPCAST(USBCCIDState, dev, dev);
 
+    usb_desc_create_serial(dev);
     usb_desc_init(dev);
     qbus_create_inplace(&s->bus.qbus, &ccid_bus_info, &dev->qdev, NULL);
     s->intr = usb_ep_get(dev, USB_TOKEN_IN, CCID_INT_IN_EP);
diff --git a/hw/usb/dev-storage.c b/hw/usb/dev-storage.c
index 3d2f244127..ae22fb1c97 100644
--- a/hw/usb/dev-storage.c
+++ b/hw/usb/dev-storage.c
@@ -546,6 +546,8 @@ static int usb_msd_initfn(USBDevice *dev)
     }
     if (s->serial) {
         usb_desc_set_string(dev, STR_SERIALNUMBER, s->serial);
+    } else {
+        usb_desc_create_serial(dev);
     }
 
     usb_desc_init(dev);
diff --git a/hw/usb/dev-wacom.c b/hw/usb/dev-wacom.c
index c1cfd74403..3b51d458f4 100644
--- a/hw/usb/dev-wacom.c
+++ b/hw/usb/dev-wacom.c
@@ -339,6 +339,7 @@ static void usb_wacom_handle_destroy(USBDevice *dev)
 static int usb_wacom_initfn(USBDevice *dev)
 {
     USBWacomState *s = DO_UPCAST(USBWacomState, dev, dev);
+    usb_desc_create_serial(dev);
     usb_desc_init(dev);
     s->changed = 1;
     return 0;