gpu: PCIe topology, consider vhost-user-block in Virt

In Virt the vhost-user-block is an PCIe device so
we need to make sure to consider it as well. We're keeping
track of vhost-user-block devices and deduce the correct
amount of PCIe root ports.

Signed-off-by: Zvonko Kaiser <zkaiser@nvidia.com>

src/runtime/pkg/device/config/config.go

@@ -216,6 +216,15 @@ func (p PCIePort) Valid() bool {
 	return false
 }
 
+type PCIePortMapping map[string]bool
+
+var (
+	// Each of this structures keeps track of the devices attached to the
+	// different types of PCI ports. We can deduces the Bus number from it
+	// and eliminate duplicates being assigned.
+	PCIeDevices = map[PCIePort]PCIePortMapping{}
+)
+
 // DeviceInfo is an embedded type that contains device data common to all types of devices.
 type DeviceInfo struct {
 	// DriverOptions is specific options for each device driver

src/runtime/pkg/device/drivers/vfio.go

@@ -31,13 +31,6 @@ const (
 	vfioAPSysfsDir      = "/sys/devices/vfio_ap"
 )
 
-var (
-	// AllPCIeDevs deduces the correct bus number. The BDF keeps track that
-	// we're not accounting for the very same device, if a user provides the
-	// devices multiple times.
-	AllPCIeDevs = map[string]bool{}
-)
-
 // VFIODevice is a vfio device meant to be passed to the hypervisor
 // to be used by the Virtual Machine.
 type VFIODevice struct {
@@ -78,9 +71,11 @@ func (device *VFIODevice) Attach(ctx context.Context, devReceiver api.DeviceRece
 	}
 	for _, vfio := range device.VfioDevs {
 		if vfio.IsPCIe {
-			vfio.Rank = len(AllPCIeDevs)
-			AllPCIeDevs[vfio.BDF] = true
-			vfio.Bus = fmt.Sprintf("%s%d", config.PCIePortPrefixMapping[vfio.Port], vfio.Rank)
+			//vfio.Rank = len(AllPCIeDevs)
+			//AllPCIeDevs[vfio.BDF] = true
+			busIndex := len(config.PCIeDevices[vfio.Port])
+			vfio.Bus = fmt.Sprintf("%s%d", config.PCIePortPrefixMapping[vfio.Port], busIndex)
+			config.PCIeDevices[vfio.Port][vfio.BDF] = true
 		}
 	}
 
@@ -214,10 +209,10 @@ func GetVFIODetails(deviceFileName, iommuDevicesPath string) (deviceBDF, deviceS
 	switch vfioDeviceType {
 	case config.VFIOPCIDeviceNormalType:
 		// Get bdf of device eg. 0000:00:1c.0
-		//deviceBDF = getBDF(deviceFileName)
+		// OLD IMPL: deviceBDF = getBDF(deviceFileName)
 		// The old implementation did not consider the case where
-		// vfio devices are located on differente root busses. The
-		// kata-agent will handle the case now, here use the full PCI addr
+		// vfio devices are located on different root busses. The
+		// kata-agent will handle the case now, here, use the full PCI addr
 		deviceBDF = deviceFileName
 		// Get sysfs path used by cloud-hypervisor
 		deviceSysfsDev = filepath.Join(config.SysBusPciDevicesPath, deviceFileName)

src/runtime/pkg/device/manager/manager.go

@@ -71,7 +71,11 @@ func NewDeviceManager(blockDriver string, vhostUserStoreEnabled bool, vhostUserS
 		dm.blockDriver = config.VirtioSCSI
 	}
 
-	drivers.AllPCIeDevs = make(map[string]bool)
+	config.PCIeDevices = make(map[config.PCIePort]config.PCIePortMapping)
+
+	config.PCIeDevices[config.RootPort] = make(map[string]bool)
+	config.PCIeDevices[config.SwitchPort] = make(map[string]bool)
+	config.PCIeDevices[config.BridgePort] = make(map[string]bool)
 
 	for _, dev := range devices {
 		dm.devices[dev.DeviceID()] = dev
@@ -118,7 +122,7 @@ func (dm *deviceManager) createDevice(devInfo config.DeviceInfo) (dev api.Device
 	}
 	if IsVFIO(devInfo.HostPath) {
 		return drivers.NewVFIODevice(&devInfo), nil
-	} else if isVhostUserBlk(devInfo) {
+	} else if IsVhostUserBlk(devInfo) {
 		if devInfo.DriverOptions == nil {
 			devInfo.DriverOptions = make(map[string]string)
 		}

src/runtime/pkg/device/manager/utils.go

@@ -37,7 +37,7 @@ func isBlock(devInfo config.DeviceInfo) bool {
 }
 
 // isVhostUserBlk checks if the device is a VhostUserBlk device.
-func isVhostUserBlk(devInfo config.DeviceInfo) bool {
+func IsVhostUserBlk(devInfo config.DeviceInfo) bool {
 	return devInfo.DevType == "b" && devInfo.Major == config.VhostUserBlkMajor
 }
 

src/runtime/pkg/device/manager/utils_test.go

@@ -70,7 +70,7 @@ func TestIsVhostUserBlk(t *testing.T) {
 	}
 
 	for _, d := range data {
-		isVhostUserBlk := isVhostUserBlk(
+		isVhostUserBlk := IsVhostUserBlk(
 			config.DeviceInfo{
 				DevType: d.devType,
 				Major:   d.major,

src/runtime/virtcontainers/hypervisor.go

@@ -505,9 +505,13 @@ type HypervisorConfig struct {
 	// MemOffset specifies memory space for nvdimm device
 	MemOffset uint64
 
-	// RawDevics are used to get PCIe device info early before the sandbox
+	// VFIODevices are used to get PCIe device info early before the sandbox
 	// is started to make better PCIe topology decisions
 	VFIODevices []config.DeviceInfo
+	// VhostUserBlkDevices are handled differently in Q35 and Virt machine
+	// type. capture them early before the sandbox to make better PCIe topology
+	// decisions
+	VhostUserBlkDevices []config.DeviceInfo
 
 	// HotplugVFIO is used to indicate if devices need to be hotplugged on the
 	// root port or a switch

src/runtime/virtcontainers/qemu.go

@@ -702,7 +702,7 @@ func (q *qemu) CreateVM(ctx context.Context, id string, network Network, hypervi
 	}
 
 	if machine.Type == QemuQ35 || machine.Type == QemuVirt {
-		if err := q.createPCIeTopology(&qemuConfig, hypervisorConfig); err != nil {
+		if err := q.createPCIeTopology(&qemuConfig, hypervisorConfig, machine.Type); err != nil {
 			q.Logger().WithError(err).Errorf("Cannot create PCIe topology")
 			return err
 		}
@@ -741,9 +741,10 @@ func (q *qemu) checkBpfEnabled() {
 // Max PCIe switch ports is 16
 // There is only 64kB of IO memory each root,switch port will consume 4k hence
 // only 16 ports possible.
-func (q *qemu) createPCIeTopology(qemuConfig *govmmQemu.Config, hypervisorConfig *HypervisorConfig) error {
+func (q *qemu) createPCIeTopology(qemuConfig *govmmQemu.Config, hypervisorConfig *HypervisorConfig, machineType string) error {
+
 	// If no-port set just return no need to add PCIe Root Port or PCIe Switches
-	if hypervisorConfig.HotPlugVFIO == config.NoPort && hypervisorConfig.ColdPlugVFIO == config.NoPort {
+	if hypervisorConfig.HotPlugVFIO == config.NoPort && hypervisorConfig.ColdPlugVFIO == config.NoPort && machineType == QemuQ35 {
 		return nil
 	}
 
@@ -767,7 +768,8 @@ func (q *qemu) createPCIeTopology(qemuConfig *govmmQemu.Config, hypervisorConfig
 		qemuConfig.FwCfg = append(qemuConfig.FwCfg, fwCfg)
 	}
 
-	// Get the number of hot(cold)-pluggable ports needed from the provided devices
+	// Get the number of hot(cold)-pluggable ports needed from the provided
+	// VFIO devices and VhostUserBlockDevices
 	var numOfPluggablePorts uint32 = 0
 	for _, dev := range hypervisorConfig.VFIODevices {
 		var err error
@@ -785,22 +787,42 @@ func (q *qemu) createPCIeTopology(qemuConfig *govmmQemu.Config, hypervisorConfig
 			}
 		}
 	}
+	vfioOnRootPort := (q.state.HotPlugVFIO == config.RootPort || q.state.ColdPlugVFIO == config.RootPort || q.state.HotplugVFIOOnRootBus)
+	vfioOnSwitchPort := (q.state.HotPlugVFIO == config.SwitchPort || q.state.ColdPlugVFIO == config.SwitchPort)
+
+	numOfVhostUserBlockDevices := len(hypervisorConfig.VhostUserBlkDevices)
+
 	// If number of PCIe root ports > 16 then bail out otherwise we may
 	// use up all slots or IO memory on the root bus and vfio-XXX-pci devices
 	// cannot be added which are crucial for Kata max slots on root bus is 32
 	// max slots on the complete pci(e) topology is 256 in QEMU
-	if numOfPluggablePorts > maxPCIeRootPort {
-		return fmt.Errorf("Number of PCIe Root Ports exceeed allowed max of %d", maxPCIeRootPort)
-	}
-	if numOfPluggablePorts > maxPCIeSwitchPort {
-		return fmt.Errorf("Number of PCIe Switch Ports exceeed allowed max of %d", maxPCIeSwitchPort)
-	}
-
-	if q.state.HotPlugVFIO == config.RootPort || q.state.ColdPlugVFIO == config.RootPort || q.state.HotplugVFIOOnRootBus {
+	if vfioOnRootPort {
+		// On Arm the vhost-user-block device is a PCIe device we need
+		// to account for it in the number of pluggable ports
+		if machineType == QemuVirt {
+			numOfPluggablePorts = numOfPluggablePorts + uint32(numOfVhostUserBlockDevices)
+		}
+		if numOfPluggablePorts > maxPCIeRootPort {
+			return fmt.Errorf("Number of PCIe Root Ports exceeed allowed max of %d", maxPCIeRootPort)
+		}
 		qemuConfig.Devices = q.arch.appendPCIeRootPortDevice(qemuConfig.Devices, numOfPluggablePorts, memSize32bit, memSize64bit)
+		return nil
 	}
-	if q.state.HotPlugVFIO == config.SwitchPort || q.state.ColdPlugVFIO == config.SwitchPort {
+	if vfioOnSwitchPort {
+		// On Arm the vhost-user-block device is a PCIe device we need
+		// to account for it in the number of pluggable ports
+		if machineType == QemuVirt {
+			numOfPluggableRootPorts := uint32(numOfVhostUserBlockDevices)
+			if numOfPluggableRootPorts > maxPCIeRootPort {
+				return fmt.Errorf("Number of PCIe Root Ports exceeed allowed max of %d", maxPCIeRootPort)
+			}
+			qemuConfig.Devices = q.arch.appendPCIeRootPortDevice(qemuConfig.Devices, numOfPluggableRootPorts, memSize32bit, memSize64bit)
+		}
+		if numOfPluggablePorts > maxPCIeSwitchPort {
+			return fmt.Errorf("Number of PCIe Switch Ports exceeed allowed max of %d", maxPCIeSwitchPort)
+		}
 		qemuConfig.Devices = q.arch.appendPCIeSwitchPortDevice(qemuConfig.Devices, numOfPluggablePorts, memSize32bit, memSize64bit)
+		return nil
 	}
 	return nil
 }
@@ -1585,6 +1607,7 @@ func (q *qemu) hotplugAddBlockDevice(ctx context.Context, drive *config.BlockDri
 }
 
 func (q *qemu) hotplugAddVhostUserBlkDevice(ctx context.Context, vAttr *config.VhostUserDeviceAttrs, op Operation, devID string) (err error) {
+
 	err = q.qmpMonitorCh.qmp.ExecuteCharDevUnixSocketAdd(q.qmpMonitorCh.ctx, vAttr.DevID, vAttr.SocketPath, false, false, vAttr.ReconnectTime)
 	if err != nil {
 		return err
@@ -1602,16 +1625,12 @@ func (q *qemu) hotplugAddVhostUserBlkDevice(ctx context.Context, vAttr *config.V
 
 	switch machineType {
 	case QemuVirt:
-		if q.state.ColdPlugVFIO.String() != "true" {
-			return fmt.Errorf("TODO: Vhost-user-blk device is a PCIe device if machine type is virt. Need to add the PCIe Root Port by setting the pcie_root_port parameter in the configuration for virt")
-		}
-
 		//The addr of a dev is corresponding with device:function for PCIe in qemu which starting from 0
 		//Since the dev is the first and only one on this bus(root port), it should be 0.
 		addr := "00"
 
-		bridgeID := fmt.Sprintf("%s%d", config.PCIeRootPortPrefix, len(drivers.AllPCIeDevs))
-		drivers.AllPCIeDevs[devID] = true
+		bridgeID := fmt.Sprintf("%s%d", config.PCIeRootPortPrefix, len(config.PCIeDevices[config.RootPort]))
+		config.PCIeDevices[config.RootPort][devID] = true
 
 		bridgeQomPath := fmt.Sprintf("%s%s", qomPathPrefix, bridgeID)
 		bridgeSlot, err := q.qomGetSlot(bridgeQomPath)

src/runtime/virtcontainers/qemu_test.go

@@ -111,9 +111,6 @@ func TestQemuCreateVM(t *testing.T) {
 	config6 := newQemuConfig()
 	config6.DisableGuestSeLinux = false
 
-	config7 := newQemuConfig()
-	config7.PCIeRootPort = 1
-
 	config8 := newQemuConfig()
 	config8.EnableVhostUserStore = true
 	config8.HugePages = true
@@ -161,7 +158,6 @@ func TestQemuCreateVM(t *testing.T) {
 		{config3, false, true},
 		{config5, false, true},
 		{config6, false, false},
-		{config7, false, true},
 		{config8, false, true},
 		{config9, true, false},
 		{config10, false, true},

src/runtime/virtcontainers/sandbox.go

@@ -621,9 +621,17 @@ func newSandbox(ctx context.Context, sandboxConfig SandboxConfig, factory Factor
 	hotPlugVFIO := (sandboxConfig.HypervisorConfig.HotPlugVFIO != config.NoPort)
 
 	var vfioDevices []config.DeviceInfo
+	// vhost-user-block device is a PCIe device in Virt, keep track of it
+	// for correct number of PCIe root ports.
+	var vhostUserBlkDevices []config.DeviceInfo
 
 	for cnt, containers := range sandboxConfig.Containers {
 		for dev, device := range containers.DeviceInfos {
+
+			if deviceManager.IsVhostUserBlk(device) {
+				vhostUserBlkDevices = append(vhostUserBlkDevices, device)
+				continue
+			}
 			isVFIO := deviceManager.IsVFIO(device.ContainerPath)
 			if hotPlugVFIO && isVFIO {
 				vfioDevices = append(vfioDevices, device)
@@ -649,6 +657,7 @@ func newSandbox(ctx context.Context, sandboxConfig SandboxConfig, factory Factor
 
 	}
 	sandboxConfig.HypervisorConfig.VFIODevices = vfioDevices
+	sandboxConfig.HypervisorConfig.VhostUserBlkDevices = vhostUserBlkDevices
 
 	// store doesn't require hypervisor to be stored immediately
 	if err = s.hypervisor.CreateVM(ctx, s.id, s.network, &sandboxConfig.HypervisorConfig); err != nil {
@@ -1930,6 +1939,7 @@ func (s *Sandbox) HotplugAddDevice(ctx context.Context, device api.Device, devTy
 		return err
 	case config.VhostUserBlk:
 		vhostUserBlkDevice, ok := device.(*drivers.VhostUserBlkDevice)
+
 		if !ok {
 			return fmt.Errorf("device type mismatch, expect device type to be %s", devType)
 		}