diff --git a/qubes/ext/pci.py b/qubes/ext/pci.py
index 63aea6dc3..ae6aeeea2 100644
--- a/qubes/ext/pci.py
+++ b/qubes/ext/pci.py
@@ -153,7 +153,10 @@ def __init__(self, port: Port, libvirt_name=None):
             dev_match = self._libvirt_regex.match(libvirt_name)
             if not dev_match:
                 raise UnsupportedDevice(libvirt_name)
-            port_id = sbdf_to_path(libvirt_name)
+            try:
+                port_id = sbdf_to_path(libvirt_name)
+            except (AssertionError, ValueError, KeyError):
+                raise UnsupportedDevice(libvirt_name)
             port = Port(
                 backend_domain=port.backend_domain,
                 port_id=port_id,