kernel: Set arguments based on CPU architecture

Kernel arguments like `intel_iommu=on` does not have sense
on AMD or ARM systems and some user might complain about
their presence, though they are likely to be harmless.

Also, on ARM systems the `iommu.passthrough` parameter is the
one to use [1].

Improve `GHWLib` to bridge CPU information from the library.
Add `CpuInfoProviderInterface` and inject it into the GenericPlugin
to implement the per CPU vendor logic.

[1] https://github.com/torvalds/linux/blob/master/Documentation/admin-guide/kernel-parameters.txt#L2343

Signed-off-by: Andrea Panattoni <[email protected]>

pkg/consts/constants.go

@@ -124,6 +124,7 @@ const (
 	KernelArgPciRealloc = "pci=realloc"
 	KernelArgIntelIommu = "intel_iommu=on"
 	KernelArgIommuPt    = "iommu=pt"
+	KernelArgIommuPassthrough    = "iommu.passthrough=1"
 
 	// Feature gates
 	// ParallelNicConfigFeatureGate: allow to configure nics in parallel

pkg/host/internal/cpu/cpu.go

@@ -0,0 +1,42 @@
+package cpu
+
+import (
+	"fmt"
+
+	ghwPkg "github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/host/internal/lib/ghw"
+	"github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/host/types"
+)
+
+
+type cpuInfoProvider struct {
+	ghwLib           ghwPkg.GHWLib
+}
+
+func New(ghwLib ghwPkg.GHWLib) *cpuInfoProvider {
+	return &cpuInfoProvider{
+		ghwLib:           ghwLib,
+	}
+}
+
+
+func (c *cpuInfoProvider) GetCPUVendor() (types.CPUVendor, error) {
+	cpuInfo, err := c.ghwLib.CPU()
+	if err != nil {
+		return -1, fmt.Errorf("can't retrieve the CPU vendor: %w", err)
+	}
+
+	if len(cpuInfo.Processors) == 0 {
+		return -1, fmt.Errorf("wrong CPU information retrieved: %v", cpuInfo)
+	}
+
+	switch (cpuInfo.Processors[0].Vendor) {
+	case "GenuineIntel":
+		return types.CPUVendorIntel, nil
+	case "AuthenticAMD":
+		return types.CPUVendorAMD, nil
+	case "ARM":
+		return types.CPUVendorARM, nil
+	}
+
+	return -1, fmt.Errorf("unknown CPU vendor: %s", cpuInfo.Processors[0].Vendor)
+}

pkg/host/internal/cpu/cpu_test.go

@@ -0,0 +1,27 @@
+package cpu
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+	"go.uber.org/zap/zapcore"
+	"sigs.k8s.io/controller-runtime/pkg/log"
+	"sigs.k8s.io/controller-runtime/pkg/log/zap"
+)
+
+
+
+var _ = Describe("Cpu", func() {
+	// TODO
+})
+
+
+func TestCpu(t *testing.T) {
+	log.SetLogger(zap.New(
+		zap.WriteTo(GinkgoWriter),
+		zap.Level(zapcore.Level(-2)),
+		zap.UseDevMode(true)))
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Package CPU Suite")
+}

pkg/host/internal/lib/ghw/ghw.go

@@ -2,6 +2,7 @@ package ghw
 
 import (
 	"github.com/jaypipes/ghw"
+	"github.com/jaypipes/ghw/pkg/cpu"
 )
 
 func New() GHWLib {
@@ -12,6 +13,9 @@ func New() GHWLib {
 type GHWLib interface {
 	// PCI returns a pointer to an Info that provide methods to access info about devices
 	PCI() (Info, error)
+
+	// CPU returns a pointer to an Info that provide methods to access info about devices
+	CPU() (*cpu.Info, error)
 }
 
 // Info interface provide methods to access info about devices
@@ -27,3 +31,7 @@ type libWrapper struct{}
 func (w *libWrapper) PCI() (Info, error) {
 	return ghw.PCI()
 }
+
+func (w *libWrapper) CPU() (*cpu.Info, error) {
+	return ghw.CPU()
+}

pkg/host/manager.go

@@ -2,6 +2,7 @@ package host
 
 import (
 	"github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/host/internal/bridge"
+	"github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/host/internal/cpu"
 	"github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/host/internal/infiniband"
 	"github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/host/internal/kernel"
 	"github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/host/internal/lib/dputils"
@@ -30,6 +31,7 @@ type HostManagerInterface interface {
 	types.VdpaInterface
 	types.InfinibandInterface
 	types.BridgeInterface
+	types.CpuInfoProviderInterface
 }
 
 type hostManager struct {
@@ -42,6 +44,7 @@ type hostManager struct {
 	types.VdpaInterface
 	types.InfinibandInterface
 	types.BridgeInterface
+	types.CpuInfoProviderInterface
 }
 
 func NewHostManager(utilsInterface utils.CmdInterface) (HostManagerInterface, error) {
@@ -61,6 +64,7 @@ func NewHostManager(utilsInterface utils.CmdInterface) (HostManagerInterface, er
 	}
 	br := bridge.New()
 	sr := sriov.New(utilsInterface, k, n, u, v, ib, netlinkLib, dpUtils, sriovnetLib, ghwLib, br)
+	cpuInfoProvider := cpu.New(ghwLib)
 	return &hostManager{
 		utilsInterface,
 		k,
@@ -71,5 +75,6 @@ func NewHostManager(utilsInterface utils.CmdInterface) (HostManagerInterface, er
 		v,
 		ib,
 		br,
+		cpuInfoProvider,
 	}, nil
 }

pkg/host/types/interfaces.go

@@ -187,3 +187,16 @@ type InfinibandInterface interface {
 	// ConfigureVfGUID configures and sets a GUID for an IB VF device
 	ConfigureVfGUID(vfAddr string, pfAddr string, vfID int, pfLink netlink.Link) error
 }
+
+type CPUVendor int
+
+const (
+	CPUVendorIntel CPUVendor = iota
+	CPUVendorAMD 
+	CPUVendorARM
+)
+
+type CpuInfoProviderInterface interface {
+	// Retrieve the CPU vendor of the current system
+	GetCPUVendor() (CPUVendor, error)
+}

pkg/plugins/generic/generic_plugin.go

@@ -13,6 +13,7 @@ import (
 	sriovnetworkv1 "github.com/k8snetworkplumbingwg/sriov-network-operator/api/v1"
 	"github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/consts"
 	"github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/helper"
+	hostTypes "github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/host/types"
 	plugin "github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/plugins"
 	"github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/utils"
 	"github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/vars"
@@ -419,9 +420,33 @@ func (p *GenericPlugin) shouldConfigureBridges() bool {
 
 func (p *GenericPlugin) addVfioDesiredKernelArg(state *sriovnetworkv1.SriovNetworkNodeState) {
 	driverState := p.DriverStateMap[Vfio]
+
+	kernelArgFnByCPUVendor := map[hostTypes.CPUVendor]func() {
+		hostTypes.CPUVendorIntel: func() {
+			p.addToDesiredKernelArgs(consts.KernelArgIntelIommu)
+			p.addToDesiredKernelArgs(consts.KernelArgIommuPt)
+		},
+		hostTypes.CPUVendorAMD: func() {
+			p.addToDesiredKernelArgs(consts.KernelArgIommuPt)
+		},
+		hostTypes.CPUVendorARM: func() {
+			p.addToDesiredKernelArgs(consts.KernelArgIommuPassthrough)
+		},
+	}
+
+
+
 	if !driverState.DriverLoaded && driverState.NeedDriverFunc(state, driverState) {
-		p.addToDesiredKernelArgs(consts.KernelArgIntelIommu)
-		p.addToDesiredKernelArgs(consts.KernelArgIommuPt)
+		cpuVendor, err := p.helpers.GetCPUVendor()
+		if err != nil {
+			log.Log.Error(err, "can't get CPU vendor, falling back to Intel")
+			cpuVendor = hostTypes.CPUVendorIntel
+		}
+
+		addKernelArgFn := kernelArgFnByCPUVendor[cpuVendor]
+		if addKernelArgFn != nil {
+			addKernelArgFn()
+		}
 	}
 }
 

pkg/plugins/generic/generic_plugin_test.go

@@ -10,6 +10,7 @@ import (
 	sriovnetworkv1 "github.com/k8snetworkplumbingwg/sriov-network-operator/api/v1"
 	"github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/consts"
 	mock_helper "github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/helper/mock"
+	hostTypes "github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/host/types"
 	plugin "github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/plugins"
 	"github.com/k8snetworkplumbingwg/sriov-network-operator/pkg/vars"
 )
@@ -850,8 +851,10 @@ var _ = Describe("Generic plugin", func() {
 			Expect(changed).To(BeTrue())
 		})
 
-		It("should detect changes on status due to missing kernel args", func() {
-			networkNodeState := &sriovnetworkv1.SriovNetworkNodeState{
+
+		Context("Kernel Args", func() {
+
+			vfioNetworkNodeState := &sriovnetworkv1.SriovNetworkNodeState{
 				Spec: sriovnetworkv1.SriovNetworkNodeStateSpec{
 					Interfaces: sriovnetworkv1.Interfaces{{
 						PciAddress: "0000:00:00.0",
@@ -896,16 +899,41 @@ var _ = Describe("Generic plugin", func() {
 				},
 			}
 
-			// Load required kernel args.
-			genericPlugin.(*GenericPlugin).addVfioDesiredKernelArg(networkNodeState)
+			It("should detect changes on status due to missing kernel args", func() {
+				hostHelper.EXPECT().GetCPUVendor().Return(hostTypes.CPUVendorIntel, nil)
 
-			hostHelper.EXPECT().GetCurrentKernelArgs().Return("", nil)
-			hostHelper.EXPECT().IsKernelArgsSet("", consts.KernelArgIntelIommu).Return(false)
-			hostHelper.EXPECT().IsKernelArgsSet("", consts.KernelArgIommuPt).Return(false)
+				// Load required kernel args.
+				genericPlugin.(*GenericPlugin).addVfioDesiredKernelArg(vfioNetworkNodeState)
 
-			changed, err := genericPlugin.CheckStatusChanges(networkNodeState)
-			Expect(err).ToNot(HaveOccurred())
-			Expect(changed).To(BeTrue())
+				Expect(genericPlugin.(*GenericPlugin).DesiredKernelArgs).To(Equal(map[string]bool{
+					consts.KernelArgIntelIommu: false,
+					consts.KernelArgIommuPt: false,
+				}))
+
+				hostHelper.EXPECT().GetCurrentKernelArgs().Return("", nil)
+				hostHelper.EXPECT().IsKernelArgsSet("", consts.KernelArgIntelIommu).Return(false)
+				hostHelper.EXPECT().IsKernelArgsSet("", consts.KernelArgIommuPt).Return(false)
+
+				changed, err := genericPlugin.CheckStatusChanges(vfioNetworkNodeState)
+				Expect(err).ToNot(HaveOccurred())
+				Expect(changed).To(BeTrue())
+			})
+
+			It("should set the correct kernel args on AMD CPUs", func() {
+				hostHelper.EXPECT().GetCPUVendor().Return(hostTypes.CPUVendorAMD, nil)
+				genericPlugin.(*GenericPlugin).addVfioDesiredKernelArg(vfioNetworkNodeState)
+				Expect(genericPlugin.(*GenericPlugin).DesiredKernelArgs).To(Equal(map[string]bool{
+					consts.KernelArgIommuPt: false,
+				}))
+			})
+
+			It("should set the correct kernel args on ARM CPUs", func() {
+				hostHelper.EXPECT().GetCPUVendor().Return(hostTypes.CPUVendorARM, nil)
+				genericPlugin.(*GenericPlugin).addVfioDesiredKernelArg(vfioNetworkNodeState)
+				Expect(genericPlugin.(*GenericPlugin).DesiredKernelArgs).To(Equal(map[string]bool{
+					consts.KernelArgIommuPassthrough: false,
+				}))
+			})
 		})
 
 		It("should load vfio_pci driver", func() {