feat(kubevirt): OCPBUGS-55974: add CPU model configuration for NodePool VMs

api/hypershift/v1beta1/kubevirt.go

@@ -12,6 +12,16 @@ const (
 
 type QoSClass string
 
+// CpuModelType represents the CPU model for KubeVirt VMs.
+//
+// +kubebuilder:validation:Enum=HostPassthrough
+type CpuModelType string
+
+const (
+	// CpuModelHostPassthrough configures the VM to use the same CPU model as the node.
+	CpuModelHostPassthrough CpuModelType = "HostPassthrough"
+)
+
 // KubevirtCompute contains values associated with the virtual compute hardware requested for the VM.
 type KubevirtCompute struct {
 	// memory represents how much guest memory the VM should have
@@ -34,6 +44,17 @@ type KubevirtCompute struct {
 	// +kubebuilder:validation:Enum=Burstable;Guaranteed
 	// +kubebuilder:default=Burstable
 	QosClass *QoSClass `json:"qosClass,omitempty"`
+
+	// model specifies the CPU model for the KubeVirt VirtualMachineInstance.
+	// Valid values are "HostPassthrough" and omitted.
+	// When not set, no explicit CPU model is configured and KubeVirt will use
+	// its default behavior.
+	// When set to "HostPassthrough", the VM will use the same CPU model as the
+	// host node, which provides the best performance but may limit live migration
+	// compatibility between nodes with different CPU types.
+	//
+	// +optional
+	Model CpuModelType `json:"model,omitempty"`
 }
 
 // +kubebuilder:validation:Enum=ReadWriteOnce;ReadWriteMany;ReadOnly;ReadWriteOncePod

api/hypershift/v1beta1/kubevirt_test.go

@@ -0,0 +1,135 @@
+package v1beta1
+
+import (
+	"encoding/json"
+	"reflect"
+	"testing"
+
+	"k8s.io/apimachinery/pkg/api/resource"
+	"k8s.io/utils/ptr"
+)
+
+// kubevirtComputeNMinus1 represents the previous version of KubevirtCompute
+// before the Model field was added. It is used to verify that JSON produced
+// by the current type can be deserialized by previous versions of the code,
+// and vice versa.
+//
+//nolint:kubeapilinter // N-1 compatibility fixture; intentionally mirrors the previous API version
+type kubevirtComputeNMinus1 struct {
+	Memory   *resource.Quantity `json:"memory,omitempty"`
+	Cores    *uint32            `json:"cores,omitempty"`
+	QosClass *QoSClass          `json:"qosClass,omitempty"`
+}
+
+func TestKubevirtComputeSerializationCompatibility(t *testing.T) {
+	burstable := QoSClassBurstable
+	guaranteed := QoSClassGuaranteed
+	mem8Gi := resource.MustParse("8Gi")
+
+	tests := []struct {
+		name          string
+		current       KubevirtCompute
+		expectedJSON  string
+		nMinus1Result kubevirtComputeNMinus1
+	}{
+		{
+			name:          "When all fields are zero-value, it should round-trip as empty object",
+			current:       KubevirtCompute{},
+			expectedJSON:  `{}`,
+			nMinus1Result: kubevirtComputeNMinus1{},
+		},
+		{
+			name: "When Model is empty, it should be omitted and N-1 should deserialize without it",
+			current: KubevirtCompute{
+				Memory:   &mem8Gi,
+				Cores:    ptr.To[uint32](4),
+				QosClass: &burstable,
+			},
+			expectedJSON: `{"memory":"8Gi","cores":4,"qosClass":"Burstable"}`,
+			nMinus1Result: kubevirtComputeNMinus1{
+				Memory:   &mem8Gi,
+				Cores:    ptr.To[uint32](4),
+				QosClass: &burstable,
+			},
+		},
+		{
+			name: "When Model is set to HostPassthrough, it should be included and N-1 should ignore it",
+			current: KubevirtCompute{
+				Memory:   &mem8Gi,
+				Cores:    ptr.To[uint32](4),
+				QosClass: &burstable,
+				Model:    CpuModelHostPassthrough,
+			},
+			expectedJSON: `{"memory":"8Gi","cores":4,"qosClass":"Burstable","model":"HostPassthrough"}`,
+			nMinus1Result: kubevirtComputeNMinus1{
+				Memory:   &mem8Gi,
+				Cores:    ptr.To[uint32](4),
+				QosClass: &burstable,
+			},
+		},
+		{
+			name: "When only Model is set, it should serialize correctly and N-1 should get empty fields",
+			current: KubevirtCompute{
+				Model: CpuModelHostPassthrough,
+			},
+			expectedJSON:  `{"model":"HostPassthrough"}`,
+			nMinus1Result: kubevirtComputeNMinus1{},
+		},
+		{
+			name: "When Model is set with Guaranteed QoS, it should round-trip correctly",
+			current: KubevirtCompute{
+				Memory:   &mem8Gi,
+				Cores:    ptr.To[uint32](8),
+				QosClass: &guaranteed,
+				Model:    CpuModelHostPassthrough,
+			},
+			expectedJSON: `{"memory":"8Gi","cores":8,"qosClass":"Guaranteed","model":"HostPassthrough"}`,
+			nMinus1Result: kubevirtComputeNMinus1{
+				Memory:   &mem8Gi,
+				Cores:    ptr.To[uint32](8),
+				QosClass: &guaranteed,
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			data, err := json.Marshal(tt.current)
+			if err != nil {
+				t.Fatalf("failed to marshal current struct: %v", err)
+			}
+			if string(data) != tt.expectedJSON {
+				t.Errorf("unexpected JSON output: got %s, want %s", string(data), tt.expectedJSON)
+			}
+
+			var nMinus1 kubevirtComputeNMinus1
+			if err := json.Unmarshal(data, &nMinus1); err != nil {
+				t.Fatalf("N-1 failed to unmarshal JSON from N: %v", err)
+			}
+			if !reflect.DeepEqual(nMinus1, tt.nMinus1Result) {
+				t.Errorf("N-1 deserialization mismatch: got %+v, want %+v", nMinus1, tt.nMinus1Result)
+			}
+
+			nMinus1Data, err := json.Marshal(tt.nMinus1Result)
+			if err != nil {
+				t.Fatalf("failed to marshal N-1 struct: %v", err)
+			}
+			var roundTripped KubevirtCompute
+			if err := json.Unmarshal(nMinus1Data, &roundTripped); err != nil {
+				t.Fatalf("N failed to unmarshal JSON from N-1: %v", err)
+			}
+			if !reflect.DeepEqual(roundTripped.Memory, tt.nMinus1Result.Memory) {
+				t.Errorf("Memory mismatch after N-1 round-trip: got %v, want %v", roundTripped.Memory, tt.nMinus1Result.Memory)
+			}
+			if !reflect.DeepEqual(roundTripped.Cores, tt.nMinus1Result.Cores) {
+				t.Errorf("Cores mismatch after N-1 round-trip: got %v, want %v", roundTripped.Cores, tt.nMinus1Result.Cores)
+			}
+			if !reflect.DeepEqual(roundTripped.QosClass, tt.nMinus1Result.QosClass) {
+				t.Errorf("QosClass mismatch after N-1 round-trip: got %v, want %v", roundTripped.QosClass, tt.nMinus1Result.QosClass)
+			}
+			if roundTripped.Model != "" {
+				t.Errorf("Model should be empty after N-1 round-trip: got %v", roundTripped.Model)
+			}
+		})
+	}
+}

api/hypershift/v1beta1/zz_generated.featuregated-crd-manifests/nodepools.hypershift.openshift.io/AAA_ungated.yaml

@@ -1139,6 +1139,18 @@ spec:
                               VM should have
                             pattern: ^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$
                             x-kubernetes-int-or-string: true
+                          model:
+                            description: |-
+                              model specifies the CPU model for the KubeVirt VirtualMachineInstance.
+                              Valid values are "HostPassthrough" and omitted.
+                              When not set, no explicit CPU model is configured and KubeVirt will use
+                              its default behavior.
+                              When set to "HostPassthrough", the VM will use the same CPU model as the
+                              host node, which provides the best performance but may limit live migration
+                              compatibility between nodes with different CPU types.
+                            enum:
+                            - HostPassthrough
+                            type: string
                           qosClass:
                             default: Burstable
                             description: |-

api/hypershift/v1beta1/zz_generated.featuregated-crd-manifests/nodepools.hypershift.openshift.io/GCPPlatform.yaml

@@ -1407,6 +1407,18 @@ spec:
                               VM should have
                             pattern: ^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$
                             x-kubernetes-int-or-string: true
+                          model:
+                            description: |-
+                              model specifies the CPU model for the KubeVirt VirtualMachineInstance.
+                              Valid values are "HostPassthrough" and omitted.
+                              When not set, no explicit CPU model is configured and KubeVirt will use
+                              its default behavior.
+                              When set to "HostPassthrough", the VM will use the same CPU model as the
+                              host node, which provides the best performance but may limit live migration
+                              compatibility between nodes with different CPU types.
+                            enum:
+                            - HostPassthrough
+                            type: string
                           qosClass:
                             default: Burstable
                             description: |-

api/hypershift/v1beta1/zz_generated.featuregated-crd-manifests/nodepools.hypershift.openshift.io/OSStreams.yaml

@@ -1172,6 +1172,18 @@ spec:
                               VM should have
                             pattern: ^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$
                             x-kubernetes-int-or-string: true
+                          model:
+                            description: |-
+                              model specifies the CPU model for the KubeVirt VirtualMachineInstance.
+                              Valid values are "HostPassthrough" and omitted.
+                              When not set, no explicit CPU model is configured and KubeVirt will use
+                              its default behavior.
+                              When set to "HostPassthrough", the VM will use the same CPU model as the
+                              host node, which provides the best performance but may limit live migration
+                              compatibility between nodes with different CPU types.
+                            enum:
+                            - HostPassthrough
+                            type: string
                           qosClass:
                             default: Burstable
                             description: |-

api/hypershift/v1beta1/zz_generated.featuregated-crd-manifests/nodepools.hypershift.openshift.io/OpenStack.yaml

@@ -1139,6 +1139,18 @@ spec:
                               VM should have
                             pattern: ^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$
                             x-kubernetes-int-or-string: true
+                          model:
+                            description: |-
+                              model specifies the CPU model for the KubeVirt VirtualMachineInstance.
+                              Valid values are "HostPassthrough" and omitted.
+                              When not set, no explicit CPU model is configured and KubeVirt will use
+                              its default behavior.
+                              When set to "HostPassthrough", the VM will use the same CPU model as the
+                              host node, which provides the best performance but may limit live migration
+                              compatibility between nodes with different CPU types.
+                            enum:
+                            - HostPassthrough
+                            type: string
                           qosClass:
                             default: Burstable
                             description: |-