clh: Hotplug the network devices

Instead of creating the VM with the network device already plugged in,
let's actually add the network device *after* the VM is created, but
*before* the Vm is actually booted.

Although it looks like it doesn't make any functional difference between
what's done in the past and what this commit introduces, this will be
used to workaround a limitation on OpenAPI when it comes to passing down
the network device's file descriptor to Cloud Hypervisor, so Cloud
Hypervisor can use it instead of opening the device by its name on the
VMM side.

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

src/runtime/virtcontainers/clh.go

@@ -148,6 +148,21 @@ func (c *clhClientApi) VmAddNetPut(ctx context.Context, netConfig chclient.NetCo
 	return c.ApiInternal.VmAddNetPut(ctx).NetConfig(netConfig).Execute()
 }
 
+// This is done in order to be able to override such a function as part of
+// our unit tests, as when testing bootVM we're on a mocked scenario already.
+var vmAddNetPutRequest = func(clh *cloudHypervisor, ctx context.Context) error {
+	cl := clh.client()
+
+	for _, netDevice := range *clh.netDevices {
+		_, _, err := cl.VmAddNetPut(ctx, netDevice)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 //
 // Cloud hypervisor state
 //
@@ -170,6 +185,7 @@ type cloudHypervisor struct {
 	APIClient      clhClient
 	ctx            context.Context
 	id             string
+	netDevices     *[]chclient.NetConfig
 	devicesIds     map[string]string
 	vmconfig       chclient.VmConfig
 	state          CloudHypervisorState
@@ -1267,6 +1283,10 @@ func openAPIClientError(err error) error {
 	return fmt.Errorf("error: %v reason: %s", err, reason)
 }
 
+func (clh *cloudHypervisor) vmAddNetPut(ctx context.Context) error {
+	return vmAddNetPutRequest(clh, ctx)
+}
+
 func (clh *cloudHypervisor) bootVM(ctx context.Context) error {
 
 	cl := clh.client()
@@ -1294,6 +1314,11 @@ func (clh *cloudHypervisor) bootVM(ctx context.Context) error {
 		return fmt.Errorf("VM state is not 'Created' after 'CreateVM'")
 	}
 
+	err = clh.vmAddNetPut(ctx)
+	if err != nil {
+		return err
+	}
+
 	clh.Logger().Debug("Booting VM")
 	_, err = cl.BootVM(ctx)
 	if err != nil {
@@ -1397,10 +1422,10 @@ func (clh *cloudHypervisor) addNet(e Endpoint) error {
 		net.SetRateLimiterConfig(*netRateLimiterConfig)
 	}
 
-	if clh.vmconfig.Net != nil {
-		*clh.vmconfig.Net = append(*clh.vmconfig.Net, *net)
+	if clh.netDevices != nil {
+		*clh.netDevices = append(*clh.netDevices, *net)
 	} else {
-		clh.vmconfig.Net = &[]chclient.NetConfig{*net}
+		clh.netDevices = &[]chclient.NetConfig{*net}
 	}
 
 	return nil

src/runtime/virtcontainers/clh_test.go

@@ -148,19 +148,19 @@ func TestCloudHypervisorAddNetCheckNetConfigListValues(t *testing.T) {
 	err := clh.addNet(e)
 	assert.Nil(err)
 
-	assert.Equal(len(*clh.vmconfig.Net), 1)
+	assert.Equal(len(*clh.netDevices), 1)
 	if err == nil {
-		assert.Equal(*(*clh.vmconfig.Net)[0].Mac, macTest)
-		assert.Equal(*(*clh.vmconfig.Net)[0].Tap, tapPath)
+		assert.Equal(*(*clh.netDevices)[0].Mac, macTest)
+		assert.Equal(*(*clh.netDevices)[0].Tap, tapPath)
 	}
 
 	err = clh.addNet(e)
 	assert.Nil(err)
 
-	assert.Equal(len(*clh.vmconfig.Net), 2)
+	assert.Equal(len(*clh.netDevices), 2)
 	if err == nil {
-		assert.Equal(*(*clh.vmconfig.Net)[1].Mac, macTest)
-		assert.Equal(*(*clh.vmconfig.Net)[1].Tap, tapPath)
+		assert.Equal(*(*clh.netDevices)[1].Mac, macTest)
+		assert.Equal(*(*clh.netDevices)[1].Tap, tapPath)
 	}
 }
 
@@ -194,7 +194,7 @@ func TestCloudHypervisorAddNetCheckEnpointTypes(t *testing.T) {
 				t.Errorf("cloudHypervisor.addNet() error = %v, wantErr %v", err, tt.wantErr)
 
 			} else if err == nil {
-				assert.Equal(*(*clh.vmconfig.Net)[0].Tap, tapPath)
+				assert.Equal(*(*clh.netDevices)[0].Tap, tapPath)
 			}
 		})
 	}
@@ -350,7 +350,7 @@ func TestCloudHypervisorNetRateLimiter(t *testing.T) {
 			if err := clh.addNet(validVeth); err != nil {
 				t.Errorf("cloudHypervisor.addNet() error = %v", err)
 			} else {
-				netConfig := (*clh.vmconfig.Net)[0]
+				netConfig := (*clh.netDevices)[0]
 
 				assert.Equal(netConfig.HasRateLimiterConfig(), tt.expectsRateLimiter)
 				if tt.expectsRateLimiter {
@@ -378,6 +378,13 @@ func TestCloudHypervisorNetRateLimiter(t *testing.T) {
 func TestCloudHypervisorBootVM(t *testing.T) {
 	clh := &cloudHypervisor{}
 	clh.APIClient = &clhClientMock{}
+
+	savedVmAddNetPutRequestFunc := vmAddNetPutRequest
+	vmAddNetPutRequest = func(clh *cloudHypervisor, ctx context.Context) error { return nil }
+	defer func() {
+		vmAddNetPutRequest = savedVmAddNetPutRequestFunc
+	}()
+
 	var ctx context.Context
 	if err := clh.bootVM(ctx); err != nil {
 		t.Errorf("cloudHypervisor.bootVM() error = %v", err)
@@ -491,6 +498,12 @@ func TestCloudHypervisorStartSandbox(t *testing.T) {
 	store, err := persist.GetDriver()
 	assert.NoError(err)
 
+	savedVmAddNetPutRequestFunc := vmAddNetPutRequest
+	vmAddNetPutRequest = func(clh *cloudHypervisor, ctx context.Context) error { return nil }
+	defer func() {
+		vmAddNetPutRequest = savedVmAddNetPutRequestFunc
+	}()
+
 	clhConfig.VMStorePath = store.RunVMStoragePath()
 	clhConfig.RunStorePath = store.RunStoragePath()