vpp_device: bind to vfio-pci before running tests

In rare cases, binding the whole /dev/vfio folder will result in
unusable VFs:
notice dpdk EAL: Cannot open /dev/vfio/151: Device or resource busy

[0], section 4.3.1. provides some clues as to what's going on and how to
avoid the failure. Mounting /dev/vfio reset the file descriptors of all
devices under /dev/vfio. Vfio-pci creates a device when an interface is
bound to it. The rare failure then occurs when /dev/vfio is mounted
while a process is using the file descriptors result in that process
using invalid file descriptors (or file descriptors belonging to a
different VF).

Fix the issue by binding i40e and ice VFs to vfio-pci before containers
are created and make sure that the VFs are not unbound later in testing.
Only bind DUT VFs since the TG uses the kernel driver.

[0]: https://connect.redhat.com/sites/default/files/2021-03/Cloud Native Network Function Requirements.pdf

Ticket: CSIT-1794

Change-Id: I83db91b29d16669fb034b141ad247f6f796fdf64
Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>

1 files changed, 8 insertions, 3 deletions

diff --git a/resources/libraries/python/DUTSetup.py b/resources/libraries/python/DUTSetup.py
index 9d0a3a8ff7..02cac03b1d 100644
--- a/resources/libraries/python/DUTSetup.py
+++ b/resources/libraries/python/DUTSetup.py
@@ -444,16 +444,21 @@ class DUTSetup:
         )
 
     @staticmethod
-    def pci_driver_unbind_list(node, *pci_addrs):
-        """Unbind PCI devices from current driver on node.
+    def unbind_pci_devices_from_other_driver(node, driver, *pci_addrs):
+        """Unbind PCI devices from driver other than input driver on node.
 
         :param node: DUT node.
+        :param driver: Driver to not unbind from. If None or empty string,
+            will attempt to unbind from the current driver.
         :param pci_addrs: PCI device addresses.
         :type node: dict
+        :type driver: str
         :type pci_addrs: list
         """
         for pci_addr in pci_addrs:
-            DUTSetup.pci_driver_unbind(node, pci_addr)
+            if not driver or \
+                    DUTSetup.get_pci_dev_driver(node, pci_addr) != driver:
+                DUTSetup.pci_driver_unbind(node, pci_addr)
 
     @staticmethod
     def pci_driver_bind(node, pci_addr, driver):