libvirt: omit PAE/ACPI/APIC features for s390x domains

[ibm-adarsh]

newDomainDef() always set x86-oriented features. On s390x, RHEL 9 + QEMU 9 with machine types like s390-ccw-virtio-rhel9.6.0 reject with virError 67 (machine type does not support ACPI), blocking worker Machine creation.

Clear the features block for s390 after resolving host arch and machine type in newDomainDefForConnection. Add unit tests (ClearX86Only).

Summary by CodeRabbit

• Bug Fixes

  • Resolved a domain configuration issue for s390 architecture guests by properly excluding x86-specific virtual machine features that were previously incorrectly applied to guest definitions.

• Tests

  • Added comprehensive unit tests to thoroughly validate that domain feature handling now works correctly across multiple different processor architectures, including both s390x and modern x86_64.

[coderabbitai]

Walkthrough

A new helper function clearX86OnlyDomainFeaturesForArch is introduced to conditionally remove x86-specific domain features for s390 architecture guests. The helper is integrated into the domain configuration flow, with unit tests validating correct behavior for s390x and x86_64 architectures.

Changes

Cohort / File(s)	Summary
Architecture-specific domain feature handling pkg/cloud/libvirt/client/domain.go	Added clearX86OnlyDomainFeaturesForArch helper function to conditionally set Domain.Features to nil for s390 guests; integrated into newDomainDefForConnection after canonical machine name is set.
Unit tests for feature clearing pkg/cloud/libvirt/client/domain_test.go	Added two test cases validating that clearX86OnlyDomainFeaturesForArch clears features for s390x architecture and preserves them for x86_64.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 11 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 14.29% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (11 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title specifically refers to omitting PAE/ACPI/APIC features for s390x domains, which directly matches the main objective: clearing x86-oriented domain features for s390 architecture to resolve compatibility issues.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Stable And Deterministic Test Names	✅ Passed	Both new test functions have stable, deterministic names without dynamic information like timestamps, UUIDs, or random identifiers.
Test Structure And Quality	✅ Passed	The custom check instructions are designed for Ginkgo test code structure, but this PR only adds standard Go unit tests using testing.T.
Microshift Test Compatibility	✅ Passed	PR adds standard Go unit tests, not Ginkgo e2e tests, making the MicroShift API compatibility check inapplicable.
Single Node Openshift (Sno) Test Compatibility	✅ Passed	New tests are standard Go unit tests using testing.T, not Ginkgo e2e tests, so the SNO compatibility check does not apply.
Topology-Aware Scheduling Compatibility	✅ Passed	PR modifies libvirt domain configuration for s390x architecture support, not Kubernetes scheduling constraints or deployment manifests.
Ote Binary Stdout Contract	✅ Passed	PR introduces only a helper function and two standard unit test functions with no process-level code modifications that could write to stdout.
Ipv6 And Disconnected Network Test Compatibility	✅ Passed	This PR does not add Ginkgo e2e tests. Only unit tests for domain configuration logic were added.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[openshift-ci]

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[openshift-ci]

Hi @ibm-adarsh. Thanks for your PR.

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[coderabbitai]

🧹 Nitpick comments (1)

pkg/cloud/libvirt/client/domain_test.go (1)

3-20: Consider asserting the emitted XML as well.

The test verifies the in-memory state; adding an XML assertion would directly cover the libvirt rejection this PR fixes (<acpi/>/<features> must be absent).

🧪 Proposed test hardening

 import (
 	"runtime"
+	"strings"
 	"testing"
 
 	libvirtxml "github.com/libvirt/libvirt-go-xml"
 )
@@
 	clearX86OnlyDomainFeaturesForArch(&d)
 	if d.Features != nil {
 		t.Fatalf("s390x: expected Features=nil, got %#v", d.Features)
 	}
+	xmlOut, err := xmlMarshallIndented(&d)
+	if err != nil {
+		t.Fatalf("s390x: failed to marshal domain XML: %v", err)
+	}
+	if strings.Contains(xmlOut, "<features") || strings.Contains(xmlOut, "<acpi") {
+		t.Fatalf("s390x: expected x86-only features to be omitted from XML, got:\n%s", xmlOut)
+	}
 }

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@pkg/cloud/libvirt/client/domain_test.go` around lines 3 - 20, Add an
assertion that the serialized XML emitted from the domain after calling
clearX86OnlyDomainFeaturesForArch does not contain a <features> or <acpi>
element: after calling newDomainDef() and clearX86OnlyDomainFeaturesForArch(&d)
serialize the domain struct to XML (using the existing libvirtxml types/imports
already in the test) and assert the resulting XML string does not contain
"<features" or "<acpi" (or that the <features> element is absent), referencing
the same symbols newDomainDef, clearX86OnlyDomainFeaturesForArch and d used in
the test.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@pkg/cloud/libvirt/client/domain_test.go`:
- Around line 3-20: Add an assertion that the serialized XML emitted from the
domain after calling clearX86OnlyDomainFeaturesForArch does not contain a
<features> or <acpi> element: after calling newDomainDef() and
clearX86OnlyDomainFeaturesForArch(&d) serialize the domain struct to XML (using
the existing libvirtxml types/imports already in the test) and assert the
resulting XML string does not contain "<features" or "<acpi" (or that the
<features> element is absent), referencing the same symbols newDomainDef,
clearX86OnlyDomainFeaturesForArch and d used in the test.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository: openshift/coderabbit/.coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 353121cb-54e3-4ed3-ab0d-09d791900e9e

📥 Commits

Reviewing files that changed from the base of the PR and between 63c1b63 and 727e82b.

📒 Files selected for processing (2)

• pkg/cloud/libvirt/client/domain.go
• pkg/cloud/libvirt/client/domain_test.go