/
gpu_sriov.go
330 lines (264 loc) · 8.85 KB
/
gpu_sriov.go
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package device
import (
"fmt"
"os"
"path/filepath"
"strconv"
"strings"
deviceConfig "github.com/canonical/lxd/lxd/device/config"
pcidev "github.com/canonical/lxd/lxd/device/pci"
"github.com/canonical/lxd/lxd/instance"
"github.com/canonical/lxd/lxd/instance/instancetype"
"github.com/canonical/lxd/lxd/resources"
"github.com/canonical/lxd/lxd/util"
"github.com/canonical/lxd/shared"
"github.com/canonical/lxd/shared/revert"
)
type gpuSRIOV struct {
deviceCommon
}
// validateConfig checks the supplied config for correctness.
func (d *gpuSRIOV) validateConfig(instConf instance.ConfigReader) error {
if !instanceSupported(instConf.Type(), instancetype.VM) {
return ErrUnsupportedDevType
}
requiredFields := []string{}
optionalFields := []string{
"vendorid",
"productid",
"id",
"pci",
}
err := d.config.Validate(gpuValidationRules(requiredFields, optionalFields))
if err != nil {
return err
}
if d.config["pci"] != "" {
for _, field := range []string{"id", "productid", "vendorid"} {
if d.config[field] != "" {
return fmt.Errorf(`Cannot use %q when "pci" is set`, field)
}
}
d.config["pci"] = pcidev.NormaliseAddress(d.config["pci"])
}
if d.config["id"] != "" {
for _, field := range []string{"pci", "productid", "vendorid"} {
if d.config[field] != "" {
return fmt.Errorf(`Cannot use %q when "id" is set`, field)
}
}
}
return nil
}
// validateEnvironment checks the runtime environment for correctness.
func (d *gpuSRIOV) validateEnvironment() error {
if d.inst.Type() == instancetype.VM && shared.IsTrue(d.inst.ExpandedConfig()["migration.stateful"]) {
return fmt.Errorf("GPU devices cannot be used when migration.stateful is enabled")
}
return validatePCIDevice(d.config["pci"])
}
// Start is run when the device is added to the instance.
func (d *gpuSRIOV) Start() (*deviceConfig.RunConfig, error) {
err := d.validateEnvironment()
if err != nil {
return nil, err
}
runConf := deviceConfig.RunConfig{}
saveData := make(map[string]string)
// Get SRIOV parent, i.e. the actual GPU.
parentPCIAddresses, err := d.getParentPCIAddresses()
if err != nil {
return nil, err
}
var parentPCIAddress string
var pciParentDev pcidev.Device
vfID := -1
// Make sure that vfio-pci is loaded.
err = util.LoadModule("vfio-pci")
if err != nil {
return nil, fmt.Errorf("Error loading %q module: %w", "vfio-pci", err)
}
// Since there might be multiple GPUs, we iterate through them and get the first free
// virtual function.
for _, parentPCIAddress = range parentPCIAddresses {
// Get PCI information about the GPU device.
devicePath := filepath.Join("/sys/bus/pci/devices", parentPCIAddress)
pciParentDev, err = pcidev.ParseUeventFile(filepath.Join(devicePath, "uevent"))
if err != nil {
err = fmt.Errorf("Failed to get PCI device info for GPU %q: %w", parentPCIAddress, err)
continue
}
vfID, err = d.findFreeVirtualFunction(pciParentDev)
if err != nil {
err = fmt.Errorf("Failed to find free virtual function: %w", err)
continue
}
if vfID > -1 {
break
}
}
if err != nil {
return nil, err
}
if vfID == -1 {
return nil, fmt.Errorf("All virtual functions on parent device seem to be in use")
}
vfPCIDev, err := d.setupSriovParent(parentPCIAddress, vfID, saveData)
if err != nil {
return nil, err
}
err = d.volatileSet(saveData)
if err != nil {
return nil, err
}
runConf.GPUDevice = append(runConf.GPUDevice, []deviceConfig.RunConfigItem{
{Key: "devName", Value: d.name},
{Key: "pciSlotName", Value: vfPCIDev.SlotName},
}...)
return &runConf, nil
}
// getParentPCIAddresses returns the PCI addresses of parent GPUs.
func (d *gpuSRIOV) getParentPCIAddresses() ([]string, error) {
gpus, err := resources.GetGPU()
if err != nil {
return nil, err
}
var parentPCIAddresses []string
for _, gpu := range gpus.Cards {
// Skip any cards that are not selected.
if !gpuSelected(d.Config(), gpu) {
continue
}
parentPCIAddresses = append(parentPCIAddresses, gpu.PCIAddress)
}
if len(parentPCIAddresses) == 0 {
return nil, fmt.Errorf("Failed to detect requested GPU device")
}
return parentPCIAddresses, nil
}
// setupSriovParent configures a SR-IOV virtual function (VF) device on parent and stores original properties of
// the physical device into voltatile for restoration on detach. Returns VF PCI device info.
func (d *gpuSRIOV) setupSriovParent(parentPCIAddress string, vfID int, volatile map[string]string) (pcidev.Device, error) {
revert := revert.New()
defer revert.Fail()
volatile["last_state.pci.parent"] = parentPCIAddress
volatile["last_state.vf.id"] = fmt.Sprintf("%d", vfID)
volatile["last_state.created"] = "false" // Indicates don't delete device at stop time.
// Get VF device's PCI Slot Name so we can unbind and rebind it from the host.
vfPCIDev, err := d.getVFDevicePCISlot(parentPCIAddress, volatile["last_state.vf.id"])
if err != nil {
return vfPCIDev, err
}
// Unbind VF device from the host so that the settings will take effect when we rebind it.
err = pcidev.DeviceUnbind(vfPCIDev)
if err != nil {
return vfPCIDev, err
}
revert.Add(func() { _ = pcidev.DeviceProbe(vfPCIDev) })
// Register VF device with vfio-pci driver so it can be passed to VM.
err = pcidev.DeviceDriverOverride(vfPCIDev, "vfio-pci")
if err != nil {
return vfPCIDev, err
}
// Record original driver used by VF device for restore.
volatile["last_state.pci.driver"] = vfPCIDev.Driver
revert.Success()
return vfPCIDev, nil
}
// getVFDevicePCISlot returns the PCI slot name for a PCI virtual function device.
func (d *gpuSRIOV) getVFDevicePCISlot(parentPCIAddress string, vfID string) (pcidev.Device, error) {
ueventFile := fmt.Sprintf("/sys/bus/pci/devices/%s/virtfn%s/uevent", parentPCIAddress, vfID)
pciDev, err := pcidev.ParseUeventFile(ueventFile)
if err != nil {
return pciDev, err
}
return pciDev, nil
}
func (d *gpuSRIOV) findFreeVirtualFunction(parentDev pcidev.Device) (int, error) {
// Get number of currently enabled VFs.
sriovNumVFs := fmt.Sprintf("/sys/bus/pci/devices/%s/sriov_numvfs", parentDev.SlotName)
sriovNumVfsBuf, err := os.ReadFile(sriovNumVFs)
if err != nil {
return 0, err
}
sriovNumVfsStr := strings.TrimSpace(string(sriovNumVfsBuf))
sriovNum, err := strconv.Atoi(sriovNumVfsStr)
if err != nil {
return 0, err
}
vfID := -1
for i := 0; i < sriovNum; i++ {
pciDev, err := pcidev.ParseUeventFile(fmt.Sprintf("/sys/bus/pci/devices/%s/virtfn%d/uevent", parentDev.SlotName, i))
if err != nil {
return 0, err
}
// We assume the virtual function is free if there's no driver bound to it.
if pciDev.Driver == "" {
vfID = i
break
}
}
return vfID, nil
}
// Stop is run when the device is removed from the instance.
func (d *gpuSRIOV) Stop() (*deviceConfig.RunConfig, error) {
runConf := deviceConfig.RunConfig{
PostHooks: []func() error{d.postStop},
}
return &runConf, nil
}
// postStop is run after the device is removed from the instance.
func (d *gpuSRIOV) postStop() error {
defer func() {
_ = d.volatileSet(map[string]string{
"last_state.created": "",
"last_state.vf.id": "",
"last_state.pci.driver": "",
"last_state.pci.parent": "",
})
}()
v := d.volatileGet()
err := d.restoreSriovParent(v)
if err != nil {
return err
}
return nil
}
// restoreSriovParent restores SR-IOV parent device settings when removed from an instance using the
// volatile data that was stored when the device was first added with setupSriovParent().
func (d *gpuSRIOV) restoreSriovParent(volatile map[string]string) error {
// Nothing to do if we don't know the original device name or the VF ID.
if volatile["last_state.pci.parent"] == "" || volatile["last_state.vf.id"] == "" || (d.config["pci"] == "" && d.config["id"] == "" && d.config["vendorid"] == "" && d.config["productid"] == "") {
return nil
}
revert := revert.New()
defer revert.Fail()
// Get VF device's PCI info so we can unbind and rebind it from the host.
vfPCIDev, err := d.getVFDevicePCISlot(volatile["last_state.pci.parent"], volatile["last_state.vf.id"])
if err != nil {
return err
}
// Unbind VF device from the host so that the restored settings will take effect when we rebind it.
err = pcidev.DeviceUnbind(vfPCIDev)
if err != nil {
return err
}
if d.inst.Type() == instancetype.VM {
// Before we bind the device back to the host, ensure we restore the original driver info as it
// should be currently set to vfio-pci.
err = pcidev.DeviceSetDriverOverride(vfPCIDev, volatile["last_state.pci.driver"])
if err != nil {
return err
}
}
// However we return from this function, we must try to rebind the VF so its not orphaned.
// The OS won't let an already bound device be bound again so is safe to call twice.
revert.Add(func() { _ = pcidev.DeviceProbe(vfPCIDev) })
// Bind VF device onto the host so that the settings will take effect.
err = pcidev.DeviceProbe(vfPCIDev)
if err != nil {
return err
}
revert.Success()
return nil
}