virt-chroot will gain the ability to create and remove mediated devices

Signed-off-by: Vladik Romanovsky <[email protected]>

cmd/virt-chroot/BUILD.bazel

@@ -4,6 +4,7 @@ go_library(
     name = "go_default_library",
     srcs = [
         "main.go",
+        "mdev-handler.go",
         "selinux.go",
         "tap-device-maker.go",
     ],
@@ -14,6 +15,7 @@ go_library(
         "//vendor/github.com/spf13/cobra:go_default_library",
         "//vendor/github.com/vishvananda/netlink:go_default_library",
         "//vendor/golang.org/x/sys/unix:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/wait:go_default_library",
     ],
 )
 

cmd/virt-chroot/main.go

@@ -184,12 +184,22 @@ func main() {
 	createTapCmd.Flags().Uint32("queue-number", 0, "the number of queues to use on multi-queued devices")
 	createTapCmd.Flags().Uint32("mtu", 1500, "the link MTU of the tap device")
 
+	createMDEVCmd := NewCreateMDEVCommand()
+	createMDEVCmd.Flags().String("type", "", "the type of a mediated device")
+	createMDEVCmd.Flags().String("parent", "", "id of a parent (e.g. PCI_ID) for the new mediated device")
+	createMDEVCmd.Flags().String("uuid", "", "uuid for the new mediated device")
+
+	removeMDEVCmd := NewRemoveMDEVCommand()
+	removeMDEVCmd.Flags().String("uuid", "", "uuid of the mediated device to remove")
+
 	rootCmd.AddCommand(
 		execCmd,
 		mntCmd,
 		umntCmd,
 		selinuxCmd,
 		createTapCmd,
+		createMDEVCmd,
+		removeMDEVCmd,
 	)
 
 	if err := rootCmd.Execute(); err != nil {

cmd/virt-chroot/mdev-handler.go

@@ -0,0 +1,109 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/spf13/cobra"
+	utilwait "k8s.io/apimachinery/pkg/util/wait"
+)
+
+var mdevBasePath string = "/sys/bus/mdev/devices"
+var mdevClassBusPath string = "/sys/class/mdev_bus"
+
+func createMDEVType(mdevType string, parentID string, uid string) error {
+
+	path := filepath.Join(mdevClassBusPath, parentID, "mdev_supported_types", mdevType, "create")
+	// wait for interface to become available
+	if !isInterfaceAvailable(path) {
+		msg := fmt.Sprintf("failed to create mdev type %s, interface is not available %s", mdevType, path)
+		errMsg := fmt.Errorf(msg)
+		fmt.Println(msg)
+		return errMsg
+	}
+	f, err := os.OpenFile(path, os.O_WRONLY, 0200)
+	if err != nil {
+		fmt.Printf("failed to create mdev type %s, can't open path %s\n", mdevType, path)
+		return err
+	}
+
+	defer f.Close()
+
+	if _, err = f.WriteString(uid); err != nil {
+		fmt.Printf("failed to create mdev type %s, can't write to %s\n", mdevType, path)
+		return err
+	}
+	fmt.Printf("Successfully created mdev %s - %s\n", mdevType, uid)
+	return nil
+}
+
+func removeMDEVType(mdevUUID string) error {
+	removePath := filepath.Join(mdevBasePath, mdevUUID, "remove")
+	// wait for interface to become available
+	if !isInterfaceAvailable(removePath) {
+		msg := fmt.Sprintf("failed to remove mdev %s, interface is not available %s", mdevUUID, removePath)
+		errMsg := fmt.Errorf(msg)
+		fmt.Println(msg)
+		return errMsg
+	}
+
+	f, err := os.OpenFile(removePath, os.O_WRONLY, 0200)
+	if err != nil {
+		fmt.Printf("failed to remove mdev %s, can't open path %s\n", mdevUUID, removePath)
+		return err
+	}
+
+	defer f.Close()
+
+	if _, err = f.WriteString("1"); err != nil {
+		fmt.Printf("failed to remove mdev %s, can't write to %s\n", mdevUUID, removePath)
+		return err
+	}
+	fmt.Printf("Successfully removed mdev %s\n", mdevUUID)
+	return nil
+}
+
+func NewCreateMDEVCommand() *cobra.Command {
+	return &cobra.Command{
+		Use:   "create-mdev",
+		Short: "create a mediate device in a given PID net ns",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			mdevType := cmd.Flag("type").Value.String()
+			parentID := cmd.Flag("parent").Value.String()
+			UID := cmd.Flag("uuid").Value.String()
+			return createMDEVType(mdevType, parentID, UID)
+		},
+	}
+}
+
+func NewRemoveMDEVCommand() *cobra.Command {
+	return &cobra.Command{
+		Use:   "remove-mdev",
+		Short: "remove a mediate device",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			mdevUUID := cmd.Flag("uuid").Value.String()
+			return removeMDEVType(mdevUUID)
+		},
+	}
+}
+
+func isInterfaceAvailable(interfacePath string) bool {
+	connectionInterval := 1 * time.Second
+	connectionTimeout := 5 * time.Second
+
+	err := utilwait.PollImmediate(connectionInterval, connectionTimeout, func() (done bool, err error) {
+		_, err = os.Stat(interfacePath)
+		if err != nil {
+			return false, nil
+		}
+		return true, nil
+	})
+
+	if err != nil {
+		fmt.Printf("interface %s is not available after multiple tries\n", interfacePath)
+		return false
+	}
+	return true
+}

pkg/virt-handler/virt-chroot/virt-chroot.go

@@ -55,6 +55,18 @@ func UmountChroot(path string) *exec.Cmd {
 	return exec.Command(binaryPath, args...)
 }
 
+func CreateMDEVType(mdevType string, parentID string, uuid string) *exec.Cmd {
+	args := append(getBaseArgs(), "create-mdev")
+	args = append(args, "--type", mdevType, "--parent", parentID, "--uuid", uuid)
+	return exec.Command(binaryPath, args...)
+}
+
+func RemoveMDEVType(mdevUUID string) *exec.Cmd {
+	args := append(getBaseArgs(), "remove-mdev")
+	args = append(args, "--uuid", mdevUUID)
+	return exec.Command(binaryPath, args...)
+}
+
 // For general purposes
 func ExecChroot(args ...string) *exec.Cmd {
 	return exec.Command(binaryPath, args...)