virtcontainers: Support TDX

Add support for Intel TDX confidential guests

fixes #1332

Signed-off-by: Julio Montes <julio.montes@intel.com>

src/runtime/virtcontainers/hypervisor_amd64.go

@@ -0,0 +1,25 @@
+// Copyright (c) 2021 Intel Corporation
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+package virtcontainers
+
+import "os"
+
+// Implementation of this function is architecture specific
+func availableGuestProtection() (guestProtection, error) {
+	flags, err := CPUFlags(procCPUInfo)
+	if err != nil {
+		return noneProtection, err
+	}
+
+	// TDX is supported and properly loaded when the firmware directory exists or `tdx` is part of the CPU flags
+	if d, err := os.Stat(tdxSysFirmwareDir); (err == nil && d.IsDir()) || flags[tdxCPUFlag] {
+		return tdxProtection, nil
+	}
+
+	// TODO: Add support for other technologies: SEV
+
+	return noneProtection, nil
+}

src/runtime/virtcontainers/qemu_amd64.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/kata-containers/kata-containers/src/runtime/virtcontainers/types"
+	"github.com/sirupsen/logrus"
 
 	govmmQemu "github.com/kata-containers/govmm/qemu"
 )
@@ -20,6 +21,8 @@ type qemuAmd64 struct {
 	qemuArchBase
 
 	vmFactory bool
+
+	devLoadersCount uint32
 }
 
 const (
@@ -30,6 +33,10 @@ const (
 	defaultQemuMachineOptions = "accel=kvm,kernel_irqchip"
 
 	qmpMigrationWaitTimeout = 5 * time.Second
+
+	tdxSysFirmwareDir = "/sys/firmware/tdx_seam/"
+
+	tdxCPUFlag = "tdx"
 )
 
 var qemuPaths = map[string]string{
@@ -201,10 +208,52 @@ func (q *qemuAmd64) appendBridges(devices []govmmQemu.Device) []govmmQemu.Device
 
 // enable protection
 func (q *qemuAmd64) enableProtection() error {
+	var err error
+	q.protection, err = availableGuestProtection()
+	if err != nil {
+		return err
+	}
+
+	switch q.protection {
+	case tdxProtection:
+		if q.qemuMachine.Options != "" {
+			q.qemuMachine.Options += ","
+		}
+		q.qemuMachine.Options += "kvm-type=tdx,confidential-guest-support=tdx"
+		q.kernelParams = append(q.kernelParams, Param{"tdx_guest", ""})
+		virtLog.WithFields(logrus.Fields{
+			"subsystem":     "qemuAmd64",
+			"machine":       q.qemuMachine,
+			"kernel-params": q.kernelParameters}).
+			Info("Enabling TDX guest protection")
 		return nil
+
+	// TODO: Add support for other x86_64 technologies: SEV
+
+	default:
+		return fmt.Errorf("This system doesn't support Confidential Computing (Guest Protection)")
+	}
 }
 
 // append protection device
 func (q *qemuAmd64) appendProtectionDevice(devices []govmmQemu.Device, firmware string) ([]govmmQemu.Device, string, error) {
+	switch q.protection {
+	case tdxProtection:
+		id := q.devLoadersCount
+		q.devLoadersCount += 1
+		return append(devices,
+			govmmQemu.Object{
+				Driver:   govmmQemu.Loader,
+				Type:     govmmQemu.TDXGuest,
+				ID:       "tdx",
+				DeviceID: fmt.Sprintf("fd%d", id),
+				Debug:    false,
+				File:     firmware,
+			}), "", nil
+	case noneProtection:
 		return devices, firmware, nil
+
+	default:
+		return devices, "", fmt.Errorf("Unsupported guest protection technology: %v", q.protection)
+	}
 }

src/runtime/virtcontainers/qemu_amd64_test.go

@@ -276,3 +276,53 @@ func TestQemuAmd64Microvm(t *testing.T) {
 
 	assert.False(amd64.supportGuestMemoryHotplug())
 }
+
+func TestQemuAmd64AppendProtectionDevice(t *testing.T) {
+	var devices []govmmQemu.Device
+	assert := assert.New(t)
+
+	amd64 := newTestQemu(assert, QemuPC)
+
+	id := amd64.(*qemuAmd64).devLoadersCount
+	firmware := "tdvf.fd"
+	var bios string
+	var err error
+	devices, bios, err = amd64.appendProtectionDevice(devices, firmware)
+	assert.NoError(err)
+
+	// non-protection
+	assert.NotEmpty(bios)
+
+	// pef protection
+	amd64.(*qemuAmd64).protection = pefProtection
+	devices, bios, err = amd64.appendProtectionDevice(devices, firmware)
+	assert.Error(err)
+	assert.Empty(bios)
+
+	// sev protection
+	// TODO: update once it's supported
+	amd64.(*qemuAmd64).protection = sevProtection
+	devices, bios, err = amd64.appendProtectionDevice(devices, firmware)
+	assert.Error(err)
+	assert.Empty(bios)
+
+	// tdxProtection
+	amd64.(*qemuAmd64).protection = tdxProtection
+
+	devices, bios, err = amd64.appendProtectionDevice(devices, firmware)
+	assert.NoError(err)
+	assert.Empty(bios)
+
+	expectedOut := []govmmQemu.Device{
+		govmmQemu.Object{
+			Driver:   govmmQemu.Loader,
+			Type:     govmmQemu.TDXGuest,
+			ID:       "tdx",
+			DeviceID: fmt.Sprintf("fd%d", id),
+			Debug:    false,
+			File:     firmware,
+		},
+	}
+
+	assert.Equal(expectedOut, devices)
+}