Add support for AN NIC without a linked synthetic device

[adityagesh]

No description provided.

[Copilot]

@adityagesh I've opened a new pull request, #4138, to work on those changes. Once the pull request is ready, I'll request review from you.

[Copilot]

Pull request overview

This pull request adds comprehensive support for Accelerated Networking (AN) NICs that operate as standalone PCI devices without synthetic NIC pairing. This architectural enhancement enables LISA to handle three distinct NIC configurations: synthetic-only NICs, traditional paired NICs (synthetic+VF), and the newly supported PCI-only NICs.

Key changes:

• Introduces a Readlink tool to replace direct readlink command execution, providing proper error handling and abstraction
• Refactors NIC detection logic to discover and handle standalone PCI NICs through device path analysis
• Updates network test suites to skip synthetic-specific tests when running on PCI-only NIC configurations

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
lisa/tools/readlink.py	New tool for reading symbolic links with proper error handling and two methods: get_target() and get_canonical_path()
lisa/tools/lspci.py	Adds get_pci_slot_from_device_path() method to extract PCI slot information from sysfs device paths
lisa/tools/init.py	Exports new Readlink tool
lisa/nic.py	Core refactoring: adds is_pci_only_nic property, renames get_lower_nics() to get_pci_nics(), adds get_synthetic_devices(), implements _discover_standalone_pci_nics() for PCI-only NIC detection
lisa/microsoft/testsuites/network/synthetic.py	Adds synthetic NIC availability checks to skip tests on PCI-only configurations
lisa/microsoft/testsuites/network/stress.py	Adds skip conditions for synthetic and SRIOV disable/enable tests on PCI-only NICs
lisa/microsoft/testsuites/network/sriov.py	Adds skip conditions for SRIOV disable/enable tests on PCI-only NICs
lisa/microsoft/testsuites/network/networksettings.py	Adds synthetic NIC checks and updates to use is_pci_module_enabled and pci_device_name properties
lisa/microsoft/testsuites/network/common.py	Updates NIC selection logic to use is_pci_module_enabled instead of checking nic.lower
lisa/microsoft/testsuites/xdp/common.py	Replaces nic.lower with nic.pci_device_name for proper PCI device name retrieval
lisa/microsoft/testsuites/power/common.py	Updates calls from get_lower_nics() to get_pci_nics()
lisa/microsoft/testsuites/performance/common.py	Updates calls from get_lower_nics() to get_pci_nics()
lisa/microsoft/testsuites/core/provisioning.py	Updates calls from get_lower_nics() to get_pci_nics() and fixes string formatting
lisa/microsoft/testsuites/xfstests/xfstesting.py	Reorganizes imports to follow PEP 8 (stdlib/third-party before local imports)
lisa/microsoft/testsuites/ltp/ltpsuite.py	Reorganizes imports to follow PEP 8
lisa/microsoft/testsuites/kselftest/kselftest-suite.py	Reorganizes imports to follow PEP 8

[Copilot]

[nitpick] The string split across lines breaks PEP 8 convention unnecessarily. The original single-line f-string was under the typical 88-100 character limit for modern Python style. Consider reverting to a single line for better readability.

[Copilot]

The new Readlink tool lacks test coverage. Consider adding unit tests to verify the tool's behavior for valid symbolic links, broken links, and the no_error_log parameter functionality, especially since this tool is now used in critical NIC discovery paths.

[Copilot]

The new _discover_standalone_pci_nics method, which is central to the PR's functionality, lacks integration test coverage. Consider adding tests that verify standalone PCI NIC discovery works correctly for PCI-only NIC configurations.