Fix handling larger root complex with PCI path

Larger systems have multiple root buses, adjust handling appropriately.

Author: marmarek

qubes/tests/devices_pci.py

@@ -24,7 +24,7 @@
 import qubes.tests
 import qubes.ext.pci
 from qubes.device_protocol import DeviceInterface
-from qubes.utils import sbdf_to_path, path_to_sbdf
+from qubes.utils import sbdf_to_path, path_to_sbdf, is_pci_path
 
 orig_open = open
 
@@ -157,7 +157,17 @@ def test_011_path_to_sbdf2(self):
         path = path_to_sbdf("0000_00_18.4")
         self.assertEqual(path, "0000:00:18.4")
 
+    def test_020_is_pci_path(self):
+        self.assertTrue(is_pci_path("0000_00_18.4"))
 
+    def test_021_is_pci_path_false(self):
+        self.assertFalse(is_pci_path("0000_c6_00.0"))
+
+    def test_022_is_pci_path_non_00_bus(self):
+        self.assertTrue(is_pci_path("0000_c0_00.0"))
+
+
+@mock.patch("qubes.utils.SYSFS_BASE", tests_sysfs_path)
 class TC_10_PCI(qubes.tests.QubesTestCase):
     def setUp(self):
         super().setUp()

qubes/utils.py

@@ -373,14 +373,18 @@ def sbdf_to_path(device_id: str):
     )
     sysfs_pci_devs_base = f"{SYSFS_BASE}/bus/pci/devices"
 
+    root_buses = [dev[3:]
+                  for dev in os.listdir(f"{SYSFS_BASE}/devices")
+                  if dev.startswith("pci")]
+
     dev_match = regex.match(device_id)
     if not dev_match:
         raise ValueError("Invalid device identifier: {!r}".format(device_id))
     if dev_match["segment"] is not None:
         segment = dev_match["segment"]
     else:
         segment = "0000"
-    if dev_match["bus"] == "00":
+    if f"{segment}:{dev_match['bus']}" in root_buses:
         return (f"{segment}_" if segment != "0000" else "") + (
             f"{dev_match['bus']}_"
             f"{dev_match['device']}.{dev_match['function']}"
@@ -488,8 +492,15 @@ def is_pci_path(device_id: str):
     :param device_id: device id to check
     :return:
     """
+
+    root_buses = [dev[3:].replace(":", "_")
+                  for dev in os.listdir(f"{SYSFS_BASE}/devices")
+                  if dev.startswith("pci")]
+    # add segment prefix for easier matching
+    if len(device_id) > 2 and device_id[2] == "_":
+        device_id = "0000_" + device_id
     path_re = re.compile(
-        r"\A([0-9a-f]{4}_)?00_[0-9a-f]{2}\.[0-9a-f]"
+        r"\A(" + "|".join(root_buses) + r")_[0-9a-f]{2}\.[0-9a-f]"
         r"(-[0-9a-f]{2}_[0-9a-f]{2}\.[0-9a-f])*\Z"
     )
     return bool(path_re.match(device_id))