Add discovery of DRM devices

This change adds the discovery of DRM devices associated with requested
devices. This means that the /dev/dri/card* and /dev/dri/renderD*
devices associated with each requested NVIDIA GPU are injected into
the container and that the /dev/dri/by-path symlinks associated with
these devices are created in the container.

Signed-off-by: Evan Lezar <elezar@nvidia.com>

internal/discover/filter.go

@@ -30,6 +30,15 @@ type filtered struct {
 	filter Filter
 }
 
+// newFilteredDisoverer creates a discoverer that applies the specified filter to the returned entities of the discoverer
+func newFilteredDisoverer(logger *logrus.Logger, applyTo Discover, filter Filter) Discover {
+	return filtered{
+		Discover: applyTo,
+		logger:   logger,
+		filter:   filter,
+	}
+}
+
 // Devices returns a filtered list of devices based on the specified filter.
 func (d filtered) Devices() ([]Device, error) {
 	devices, err := d.Discover.Devices()

internal/discover/graphics.go

@@ -18,13 +18,21 @@ package discover
 
 import (
 	"fmt"
+	"os"
+	"path/filepath"
 
+	"github.com/NVIDIA/nvidia-container-toolkit/internal/config/image"
+	"github.com/NVIDIA/nvidia-container-toolkit/internal/info/drm"
+	"github.com/NVIDIA/nvidia-container-toolkit/internal/info/proc"
 	"github.com/NVIDIA/nvidia-container-toolkit/internal/lookup"
+	"github.com/container-orchestrated-devices/container-device-interface/pkg/cdi"
 	"github.com/sirupsen/logrus"
 )
 
 // NewGraphicsDiscoverer returns the discoverer for graphics tools such as Vulkan.
-func NewGraphicsDiscoverer(logger *logrus.Logger, root string) (Discover, error) {
+func NewGraphicsDiscoverer(logger *logrus.Logger, devices image.VisibleDevices, cfg *Config) (Discover, error) {
+	root := cfg.Root
+
 	locator, err := lookup.NewLibraryLocator(logger, root)
 	if err != nil {
 		return nil, fmt.Errorf("failed to construct library locator: %v", err)
@@ -54,10 +62,193 @@ func NewGraphicsDiscoverer(logger *logrus.Logger, root string) (Discover, error)
 		},
 	)
 
+	drmDeviceNodes, err := newDRMDeviceDiscoverer(logger, devices, root)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create DRM device discoverer: %v", err)
+	}
+
+	drmByPathSymlinks := newCreateDRMByPathSymlinks(logger, drmDeviceNodes, cfg)
+
 	discover := Merge(
+		Merge(drmDeviceNodes, drmByPathSymlinks),
 		libraries,
 		jsonMounts,
 	)
 
 	return discover, nil
 }
+
+type drmDevicesByPath struct {
+	None
+	logger                  *logrus.Logger
+	lookup                  lookup.Locator
+	nvidiaCTKExecutablePath string
+	root                    string
+	devicesFrom             Discover
+}
+
+// newCreateDRMByPathSymlinks creates a discoverer for a hook to create the by-path symlinks for DRM devices discovered by the specified devices discoverer
+func newCreateDRMByPathSymlinks(logger *logrus.Logger, devices Discover, cfg *Config) Discover {
+	d := drmDevicesByPath{
+		logger:                  logger,
+		lookup:                  lookup.NewExecutableLocator(logger, cfg.Root),
+		nvidiaCTKExecutablePath: cfg.NVIDIAContainerToolkitCLIExecutablePath,
+		root:                    cfg.Root,
+		devicesFrom:             devices,
+	}
+
+	return &d
+}
+
+// Hooks returns a hook to create the symlinks from the required CSV files
+func (d drmDevicesByPath) Hooks() ([]Hook, error) {
+	devices, err := d.devicesFrom.Devices()
+	if err != nil {
+		return nil, fmt.Errorf("failed to discover devices for by-path symlinks: %v", err)
+	}
+	if len(devices) == 0 {
+		return nil, nil
+	}
+
+	hookPath := nvidiaCTKDefaultFilePath
+	targets, err := d.lookup.Locate(d.nvidiaCTKExecutablePath)
+	if err != nil {
+		d.logger.Warnf("Failed to locate %v: %v", d.nvidiaCTKExecutablePath, err)
+	} else if len(targets) == 0 {
+		d.logger.Warnf("%v not found", d.nvidiaCTKExecutablePath)
+	} else {
+		d.logger.Debugf("Found %v candidates: %v", d.nvidiaCTKExecutablePath, targets)
+		hookPath = targets[0]
+	}
+	d.logger.Debugf("Using NVIDIA Container Toolkit CLI path %v", hookPath)
+
+	args := []string{hookPath, "hook", "create-symlinks"}
+	links, err := d.getSpecificLinkArgs(devices)
+	if err != nil {
+		return nil, fmt.Errorf("failed to determine specific links: %v", err)
+	}
+	for _, l := range links {
+		args = append(args, "--link", l)
+	}
+
+	h := Hook{
+		Lifecycle: cdi.CreateContainerHook,
+		Path:      hookPath,
+		Args:      args,
+	}
+
+	return []Hook{h}, nil
+}
+
+// getSpecificLinkArgs returns the required specic links that need to be created
+func (d drmDevicesByPath) getSpecificLinkArgs(devices []Device) ([]string, error) {
+	selectedDevices := make(map[string]bool)
+	for _, d := range devices {
+		selectedDevices[filepath.Base(d.HostPath)] = true
+	}
+
+	linkLocator := lookup.NewFileLocator(d.logger, d.root)
+	candidates, err := linkLocator.Locate("/dev/dri/by-path/pci-*-*")
+	if err != nil {
+		return nil, fmt.Errorf("failed to locate devices by path: %v", err)
+	}
+
+	var links []string
+	for _, c := range candidates {
+		device, err := os.Readlink(c)
+		if err != nil {
+			d.logger.Warningf("Failed to evaluate symlink %v; ignoring", c)
+			continue
+		}
+
+		if selectedDevices[filepath.Base(device)] {
+			d.logger.Debugf("adding device symlink %v -> %v", c, device)
+			links = append(links, fmt.Sprintf("%v::%v", device, c))
+		}
+	}
+
+	return links, nil
+}
+
+// newDRMDeviceDiscoverer creates a discoverer for the DRM devices associated with the requested devices.
+func newDRMDeviceDiscoverer(logger *logrus.Logger, devices image.VisibleDevices, root string) (Discover, error) {
+	allDevices := NewDeviceDiscoverer(
+		logger,
+		lookup.NewCharDeviceLocator(logger, root),
+		root,
+		[]string{
+			"/dev/dri/card*",
+			"/dev/dri/renderD*",
+		},
+	)
+
+	filter, err := newDRMDeviceFilter(logger, devices, root)
+	if err != nil {
+		return nil, fmt.Errorf("failed to construct DRM device filter: %v", err)
+	}
+
+	// We return a discoverer that applies the DRM device filter created above to all discovered DRM device nodes.
+	d := newFilteredDisoverer(
+		logger,
+		allDevices,
+		filter,
+	)
+
+	return d, err
+}
+
+// newDRMDeviceFilter creates a filter that matches DRM devices nodes for the visible devices.
+func newDRMDeviceFilter(logger *logrus.Logger, devices image.VisibleDevices, root string) (Filter, error) {
+	gpuInformationPaths, err := proc.GetInformationFilePaths(root)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read GPU information: %v", err)
+	}
+
+	var selectedBusIds []string
+	for _, f := range gpuInformationPaths {
+		info, err := proc.ParseGPUInformationFile(f)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse %v: %v", f, err)
+		}
+		uuid := info[proc.GPUInfoGPUUUID]
+		busID := info[proc.GPUInfoBusLocation]
+		minor := info[proc.GPUInfoDeviceMinor]
+
+		if devices.Has(minor) || devices.Has(uuid) || devices.Has(busID) {
+			selectedBusIds = append(selectedBusIds, busID)
+		}
+	}
+
+	filter := make(selectDeviceByPath)
+	for _, busID := range selectedBusIds {
+		drmDeviceNodes, err := drm.GetDeviceNodesByBusID(busID)
+		if err != nil {
+			return nil, fmt.Errorf("failed to determine DRM devices for %v: %v", busID, err)
+		}
+		for _, drmDeviceNode := range drmDeviceNodes {
+			filter[filepath.Join(drmDeviceNode)] = true
+		}
+	}
+
+	return filter, nil
+}
+
+// selectDeviceByPath is a filter that allows devices to be selected by the path
+type selectDeviceByPath map[string]bool
+
+var _ Filter = (*selectDeviceByPath)(nil)
+
+// DeviceIsSelected determines whether the device's path has been selected
+func (s selectDeviceByPath) DeviceIsSelected(device Device) bool {
+	return s[device.Path]
+}
+
+// MountIsSelected is always true
+func (s selectDeviceByPath) MountIsSelected(Mount) bool {
+	return true
+}
+
+// HookIsSelected is always true
+func (s selectDeviceByPath) HookIsSelected(Hook) bool {
+	return true
+}

internal/modifier/graphics.go

@@ -44,7 +44,15 @@ func NewGraphicsModifier(logger *logrus.Logger, cfg *config.Config, ociSpec oci.
 		return nil, nil
 	}
 
-	d, err := discover.NewGraphicsDiscoverer(logger, cfg.NVIDIAContainerCLIConfig.Root)
+	config := &discover.Config{
+		Root:                                    cfg.NVIDIAContainerCLIConfig.Root,
+		NVIDIAContainerToolkitCLIExecutablePath: cfg.NVIDIACTKConfig.Path,
+	}
+	d, err := discover.NewGraphicsDiscoverer(
+		logger,
+		image.DevicesFromEnvvars(visibleDevicesEnvvar),
+		config,
+	)
 	if err != nil {
 		return nil, fmt.Errorf("failed to construct discoverer: %v", err)
 	}