vpp: T7819: do not override driver if it is already done

[sever-sever]

Change summary

Do not override already overridden drivers

Fixes this case:

Traceback (most recent call last):
  File "/usr/libexec/vyos/services/vyos-configd", line 156, in run_script
    script.apply(c)
  File "/usr/libexec/vyos/conf_mode/vpp.py", line 613, in apply
    control_host.override_driver(
  File "/usr/lib/python3/dist-packages/vyos/vpp/control_host.py", line 138, in override_driver
    Path('/sys/module/vfio_pci/drivers/pci:vfio-pci/new_id').write_text(
  File "/usr/lib/python3.11/pathlib.py", line 1079, in write_text
    with self.open(mode='w', encoding=encoding, errors=errors, newline=newline) as f:
FileExistsError: [Errno 17] File exists

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

• https://vyos.dev/T7819

Related PR(s)

How to test / Smoketest result

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

[github-actions]

👍
No issues in PR Title / Commit Title

[Copilot]

Pull Request Overview

This PR fixes a FileExistsError that occurs when VPP attempts to override a driver that has already been overridden. The fix adds exception handling to gracefully handle the case where the vendor/device ID pair is already registered with vfio-pci.

Key changes:

• Added try-except block around the vfio-pci new_id write operation
• FileExistsError is now silently ignored (expected behavior)
• Generic exceptions are caught and logged as warnings

Comments suppressed due to low confidence (1)

python/vyos/vpp/control_host.py:144

• 'except' clause does nothing but pass and there is no explanatory comment.

        except FileExistsError:

---

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[github-actions]

CI integration 👍 passed!

Details

CI logs

• CLI Smoketests (no interfaces) 👍 passed
• CLI Smoketests VPP 👍 passed
• CLI Smoketests (interfaces only) 👍 passed
• Config tests 👍 passed
• Config tests VPP 👍 passed
• RAID1 tests 👍 passed
• TPM tests 👍 passed

[alexk37]

Fix works on AWS vm with ENA driver

vyos@VyOS-for-Smoke-Tests# set vpp settings int eth1 driver dpdk
[edit]
vyos@VyOS-for-Smoke-Tests# commit
[ vpp ]

WARNING: NOTE: Current dataplane capacity (estimated): 2.1 M IPv4
routes. Exceeding these values will lead to a dataplane out-of-memory
condition and a crash. Extensive use of features like ACLs, NAT and
others may reduce the numbers above. Please read the documentation for
details: https://docs.vyos.io/


[edit]
vyos@VyOS-for-Smoke-Tests# set vpp settings int eth2 driver dpdk
[edit]
vyos@VyOS-for-Smoke-Tests# commit
[ vpp ]

WARNING: NOTE: Current dataplane capacity (estimated): 2.1 M IPv4
routes. Exceeding these values will lead to a dataplane out-of-memory
condition and a crash. Extensive use of features like ACLs, NAT and
others may reduce the numbers above. Please read the documentation for
details: https://docs.vyos.io/


[edit]
vyos@VyOS-for-Smoke-Tests#

[zdc]

We have encountered a similar case with something in VPP before, and my previous response still applies here.

Whether the suggested solution is appropriate depends on understanding why the drivers are in unexpected states at the moment the function is called. This is what we need to investigate.

[sever-sever]

@zdc Can you close the PR if the fix is not acceptable?
We don’t have another solution at the moment.