Limit guest CPUs to two threads if NUMA passthrough is selected

Signed-off-by: Roman Mohr <[email protected]>
jrife · Sep 9, 2021 · 8f507ab · 8f507ab
1 parent dd02a8c
commit 8f507ab
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diff --git a/pkg/virt-api/webhooks/validating-webhook/admitters/vmi-create-admitter.go b/pkg/virt-api/webhooks/validating-webhook/admitters/vmi-create-admitter.go
@@ -981,6 +981,7 @@ func validateCpuPinning(field *k8sfield.Path, spec *v1.VirtualMachineInstanceSpe
 		causes = append(causes, validateRequestLimitOrCoresProvidedOnDedicatedCPUPlacement(field, spec)...)
 		causes = append(causes, validateRequestEqualsLimitOnDedicatedCPUPlacement(field, spec)...)
 		causes = append(causes, validateRequestOrLimitWithCoresProvidedOnDedicatedCPUPlacement(field, spec)...)
+		causes = append(causes, validateThreadCountOnDedicatedCPUPlacement(field, spec)...)
 	}
 	return causes
 }
@@ -1019,6 +1020,20 @@ func validateNUMA(field *k8sfield.Path, spec *v1.VirtualMachineInstanceSpec, con
 	return causes
 }
 
+func validateThreadCountOnDedicatedCPUPlacement(field *k8sfield.Path, spec *v1.VirtualMachineInstanceSpec) (causes []metav1.StatusCause) {
+	if spec.Domain.CPU != nil && spec.Domain.CPU.Threads > 2 {
+		causes = append(causes, metav1.StatusCause{
+			Type: metav1.CauseTypeFieldValueInvalid,
+			Message: fmt.Sprintf("Not more than two threads must be provided at %v (got %v) when DedicatedCPUPlacement is true",
+				field.Child("domain", "cpu", "threads").String(),
+				spec.Domain.CPU.Threads,
+			),
+			Field: field.Child("domain", "cpu", "dedicatedCpuPlacement").String(),
+		})
+	}
+	return causes
+}
+
 func validateRequestOrLimitWithCoresProvidedOnDedicatedCPUPlacement(field *k8sfield.Path, spec *v1.VirtualMachineInstanceSpec) (causes []metav1.StatusCause) {
 	if (spec.Domain.Resources.Requests.Cpu().Value() > 0 || spec.Domain.Resources.Limits.Cpu().Value() > 0) && hwutil.GetNumberOfVCPUs(spec.Domain.CPU) > 0 &&
 		spec.Domain.Resources.Requests.Cpu().Value() != hwutil.GetNumberOfVCPUs(spec.Domain.CPU) && spec.Domain.Resources.Limits.Cpu().Value() != hwutil.GetNumberOfVCPUs(spec.Domain.CPU) {

diff --git a/pkg/virt-api/webhooks/validating-webhook/admitters/vmi-create-admitter_test.go b/pkg/virt-api/webhooks/validating-webhook/admitters/vmi-create-admitter_test.go
@@ -2276,6 +2276,18 @@ var _ = Describe("Validating VMICreate Admitter", func() {
 			causes := ValidateVirtualMachineInstanceSpec(k8sfield.NewPath("fake"), &vmi.Spec, config)
 			Expect(causes).To(BeEmpty())
 		})
+		It("should reject specs with more than two threads", func() {
+			vmi.Spec.Domain.Memory = &v1.Memory{Hugepages: &v1.Hugepages{PageSize: "2Mi"}}
+			vmi.Spec.Domain.CPU.Cores = 4
+			vmi.Spec.Domain.CPU.Threads = 3
+			vmi.Spec.Domain.CPU.NUMA = &v1.NUMA{GuestMappingPassthrough: &v1.NUMAGuestMappingPassthrough{}}
+			vmi.Spec.Domain.Resources.Limits = k8sv1.ResourceList{
+				k8sv1.ResourceCPU: resource.MustParse("12"),
+			}
+			causes := ValidateVirtualMachineInstanceSpec(k8sfield.NewPath("fake"), &vmi.Spec, config)
+			Expect(causes).To(HaveLen(1))
+			Expect(causes[0].Message).To(ContainSubstring("Not more than two threads must be provided at fake.domain.cpu.threads (got 3) when DedicatedCPUPlacement is true"))
+		})
 		It("should reject specs without cpu reqirements", func() {
 			causes := ValidateVirtualMachineInstanceSpec(k8sfield.NewPath("fake"), &vmi.Spec, config)
 			Expect(len(causes)).To(Equal(1))