qemu: Add virtio-mem support

This commit adds qemu virtio-mem support.
Then qemu can use virtio-mem support memory resize.

To enable this function, need the Linux and the qemu that support
virtio-mem.
Use command "echo 1 > /proc/sys/vm/overcommit_memory" to enable memory
overcommitment of the Linux kernel.  Because qemu virtio-mem device need
to allocate a lot of memory.
Set "enable_virtio_mem" of kata configuration to true.

Fixes: #2406

Signed-off-by: Hui Zhu <teawater@antfin.com>

cli/config/configuration-qemu.toml.in

@@ -89,6 +89,12 @@ default_memory = @DEFMEMSZ@
 # Default 0
 #memory_offset = 0
 
+# Specifies virtio-mem will be enabled or not.
+# Please note that this option should be used with the command
+# "echo 1 > /proc/sys/vm/overcommit_memory".
+# Default false
+#enable_virtio_mem = true
+
 # Disable block device from being used for a container's rootfs.
 # In case of a storage driver like devicemapper where a container's 
 # root file system is backed by a block device, the block device is passed

pkg/katautils/config-settings.go

@@ -27,6 +27,7 @@ const defaultMaxVCPUCount uint32 = 0
 const defaultMemSize uint32 = 2048 // MiB
 const defaultMemSlots uint32 = 10
 const defaultMemOffset uint32 = 0 // MiB
+const defaultVirtioMem bool = false
 const defaultBridgesCount uint32 = 1
 const defaultInterNetworkingModel = "tcfilter"
 const defaultDisableBlockDeviceUse bool = false

pkg/katautils/config.go

@@ -114,6 +114,7 @@ type hypervisor struct {
 	DisableBlockDeviceUse   bool     `toml:"disable_block_device_use"`
 	MemPrealloc             bool     `toml:"enable_mem_prealloc"`
 	HugePages               bool     `toml:"enable_hugepages"`
+	VirtioMem               bool     `toml:"enable_virtio_mem"`
 	FileBackedMemRootDir    string   `toml:"file_mem_backend"`
 	Swap                    bool     `toml:"enable_swap"`
 	Debug                   bool     `toml:"enable_debug"`
@@ -623,6 +624,7 @@ func newQemuHypervisorConfig(h hypervisor) (vc.HypervisorConfig, error) {
 		MemorySize:              h.defaultMemSz(),
 		MemSlots:                h.defaultMemSlots(),
 		MemOffset:               h.defaultMemOffset(),
+		VirtioMem:               h.VirtioMem,
 		EntropySource:           h.GetEntropySource(),
 		DefaultBridges:          h.defaultBridges(),
 		DisableBlockDeviceUse:   h.DisableBlockDeviceUse,
@@ -773,6 +775,7 @@ func newClhHypervisorConfig(h hypervisor) (vc.HypervisorConfig, error) {
 		MemorySize:              h.defaultMemSz(),
 		MemSlots:                h.defaultMemSlots(),
 		MemOffset:               h.defaultMemOffset(),
+		VirtioMem:               h.VirtioMem,
 		EntropySource:           h.GetEntropySource(),
 		DefaultBridges:          h.defaultBridges(),
 		DisableBlockDeviceUse:   h.DisableBlockDeviceUse,
@@ -1054,6 +1057,7 @@ func GetDefaultHypervisorConfig() vc.HypervisorConfig {
 		DefaultMaxVCPUs:         defaultMaxVCPUCount,
 		MemorySize:              defaultMemSize,
 		MemOffset:               defaultMemOffset,
+		VirtioMem:               defaultVirtioMem,
 		DisableBlockDeviceUse:   defaultDisableBlockDeviceUse,
 		DefaultBridges:          defaultBridgesCount,
 		MemPrealloc:             defaultEnableMemPrealloc,

virtcontainers/hypervisor.go

@@ -307,6 +307,9 @@ type HypervisorConfig struct {
 	// VirtioFSExtraArgs passes options to virtiofsd daemon
 	VirtioFSExtraArgs []string
 
+	// File based memory backend root directory
+	FileBackedMemRootDir string
+
 	// customAssets is a map of assets.
 	// Each value in that map takes precedence over the configured assets.
 	// For example, if there is a value for the "kernel" key in this map,
@@ -341,8 +344,8 @@ type HypervisorConfig struct {
 	// HugePages specifies if the memory should be pre-allocated from huge pages
 	HugePages bool
 
-	// File based memory backend root directory
-	FileBackedMemRootDir string
+	// VirtioMem is used to enable/disable virtio-mem
+	VirtioMem bool
 
 	// Realtime Used to enable/disable realtime
 	Realtime bool

virtcontainers/persist.go

@@ -214,6 +214,7 @@ func (s *Sandbox) dumpConfig(ss *persistapi.SandboxState) {
 		Msize9p:                 sconfig.HypervisorConfig.Msize9p,
 		MemSlots:                sconfig.HypervisorConfig.MemSlots,
 		MemOffset:               sconfig.HypervisorConfig.MemOffset,
+		VirtioMem:               sconfig.HypervisorConfig.VirtioMem,
 		VirtioFSCacheSize:       sconfig.HypervisorConfig.VirtioFSCacheSize,
 		KernelPath:              sconfig.HypervisorConfig.KernelPath,
 		ImagePath:               sconfig.HypervisorConfig.ImagePath,
@@ -499,6 +500,7 @@ func loadSandboxConfig(id string) (*SandboxConfig, error) {
 		Msize9p:                 hconf.Msize9p,
 		MemSlots:                hconf.MemSlots,
 		MemOffset:               hconf.MemOffset,
+		VirtioMem:               hconf.VirtioMem,
 		VirtioFSCacheSize:       hconf.VirtioFSCacheSize,
 		KernelPath:              hconf.KernelPath,
 		ImagePath:               hconf.ImagePath,

virtcontainers/persist/api/config.go

@@ -97,6 +97,9 @@ type HypervisorConfig struct {
 	// VirtioFSExtraArgs passes options to virtiofsd daemon
 	VirtioFSExtraArgs []string
 
+	// File based memory backend root directory
+	FileBackedMemRootDir string
+
 	// BlockDeviceCacheSet specifies cache-related options will be set to block devices or not.
 	BlockDeviceCacheSet bool
 
@@ -125,8 +128,8 @@ type HypervisorConfig struct {
 	// HugePages specifies if the memory should be pre-allocated from huge pages
 	HugePages bool
 
-	// File based memory backend root directory
-	FileBackedMemRootDir string
+	// VirtioMem is used to enable/disable virtio-mem
+	VirtioMem bool
 
 	// Realtime Used to enable/disable realtime
 	Realtime bool

virtcontainers/pkg/annotations/annotations.go

@@ -124,6 +124,9 @@ const (
 	// MemOffset is a sandbox annotation that specifies the memory space used for nvdimm device by the hypervisor.
 	MemOffset = kataAnnotHypervisorPrefix + "memory_offset"
 
+	// VirtioMem is a sandbox annotation that is used to enable/disable virtio-mem.
+	VirtioMem = kataAnnotHypervisorPrefix + "enable_virtio_mem"
+
 	// MemPrealloc is a sandbox annotation that specifies the memory space used for nvdimm device by the hypervisor.
 	MemPrealloc = kataAnnotHypervisorPrefix + "enable_mem_prealloc"
 

virtcontainers/pkg/oci/utils.go

@@ -492,6 +492,15 @@ func addHypervisorMemoryOverrides(ocispec specs.Spec, sbConfig *vc.SandboxConfig
 		}
 	}
 
+	if value, ok := ocispec.Annotations[vcAnnotations.VirtioMem]; ok {
+		virtioMem, err := strconv.ParseBool(value)
+		if err != nil {
+			return fmt.Errorf("Error parsing annotation for enable_virtio_mem: Please specify boolean value 'true|false'")
+		}
+
+		sbConfig.HypervisorConfig.VirtioMem = virtioMem
+	}
+
 	if value, ok := ocispec.Annotations[vcAnnotations.MemPrealloc]; ok {
 		memPrealloc, err := strconv.ParseBool(value)
 		if err != nil {

virtcontainers/pkg/oci/utils_test.go

@@ -741,6 +741,7 @@ func TestAddHypervisorAnnotations(t *testing.T) {
 	ocispec.Annotations[vcAnnotations.DefaultMemory] = "1024"
 	ocispec.Annotations[vcAnnotations.MemSlots] = "20"
 	ocispec.Annotations[vcAnnotations.MemOffset] = "512"
+	ocispec.Annotations[vcAnnotations.VirtioMem] = "true"
 	ocispec.Annotations[vcAnnotations.MemPrealloc] = "true"
 	ocispec.Annotations[vcAnnotations.EnableSwap] = "true"
 	ocispec.Annotations[vcAnnotations.FileBackedMemRootDir] = "/dev/shm"
@@ -770,6 +771,7 @@ func TestAddHypervisorAnnotations(t *testing.T) {
 	assert.Equal(config.HypervisorConfig.MemorySize, uint32(1024))
 	assert.Equal(config.HypervisorConfig.MemSlots, uint32(20))
 	assert.Equal(config.HypervisorConfig.MemOffset, uint32(512))
+	assert.Equal(config.HypervisorConfig.VirtioMem, true)
 	assert.Equal(config.HypervisorConfig.MemPrealloc, true)
 	assert.Equal(config.HypervisorConfig.Mlock, false)
 	assert.Equal(config.HypervisorConfig.FileBackedMemRootDir, "/dev/shm")

virtcontainers/qemu.go

@@ -668,6 +668,56 @@ func (q *qemu) setupVirtiofsd() (err error) {
 	return err
 }
 
+func (q *qemu) getMemArgs() (bool, string, string) {
+	share := false
+	target := ""
+	memoryBack := "memory-backend-ram"
+
+	if q.qemuConfig.Knobs.HugePages {
+		// we are setting all the bits that govmm sets when hugepages are enabled.
+		// https://github.com/intel/govmm/blob/master/qemu/qemu.go#L1677
+		target = "/dev/hugepages"
+		memoryBack = "memory-backend-file"
+		share = true
+	} else if q.config.SharedFS == config.VirtioFS || q.config.FileBackedMemRootDir != "" {
+		target = q.qemuConfig.Memory.Path
+		memoryBack = "memory-backend-file"
+	}
+	if q.qemuConfig.Knobs.MemShared {
+		share = true
+	}
+
+	return share, target, memoryBack
+}
+
+func (q *qemu) setupVirtioMem() error {
+	maxMem, err := q.hostMemMB()
+	if err != nil {
+		return err
+	}
+	// 1024 is size for nvdimm
+	sizeMB := int(maxMem) - int(q.config.MemorySize)
+
+	share, target, memoryBack := q.getMemArgs()
+	err = q.qmpSetup()
+	if err != nil {
+		return err
+	}
+	err = q.qmpMonitorCh.qmp.ExecMemdevAdd(q.qmpMonitorCh.ctx, memoryBack, "virtiomem", target, sizeMB, share, "virtio-mem-pci", "virtiomem0")
+	if err == nil {
+		q.config.VirtioMem = true
+		q.Logger().Infof("Setup %dMB virtio-mem-pci success", sizeMB)
+	} else {
+		help := ""
+		if strings.Contains(err.Error(), "Cannot allocate memory") {
+			help = ".  Please use command \"echo 1 > /proc/sys/vm/overcommit_memory\" handle it."
+		}
+		err = fmt.Errorf("Add %dMB virtio-mem-pci fail %s%s", sizeMB, err.Error(), help)
+	}
+
+	return err
+}
+
 // startSandbox will start the Sandbox's VM.
 func (q *qemu) startSandbox(timeout int) error {
 	span, _ := q.trace("startSandbox")
@@ -744,6 +794,10 @@ func (q *qemu) startSandbox(timeout int) error {
 		}
 	}
 
+	if q.config.VirtioMem {
+		err = q.setupVirtioMem()
+	}
+
 	return err
 }
 
@@ -1449,9 +1503,6 @@ func (q *qemu) hotplugMemory(memDev *memoryDevice, op operation) (int, error) {
 
 func (q *qemu) hotplugAddMemory(memDev *memoryDevice) (int, error) {
 	memoryDevices, err := q.qmpMonitorCh.qmp.ExecQueryMemoryDevices(q.qmpMonitorCh.ctx)
-	share := false
-	target := ""
-	memoryBack := "memory-backend-ram"
 	if err != nil {
 		return 0, fmt.Errorf("failed to query memory devices: %v", err)
 	}
@@ -1465,19 +1516,8 @@ func (q *qemu) hotplugAddMemory(memDev *memoryDevice) (int, error) {
 		}
 		memDev.slot = maxSlot + 1
 	}
-	if q.qemuConfig.Knobs.HugePages {
-		// we are setting all the bits that govmm sets when hugepages are enabled.
-		// https://github.com/intel/govmm/blob/master/qemu/qemu.go#L1677
-		target = "/dev/hugepages"
-		memoryBack = "memory-backend-file"
-		share = true
-	} else if q.config.SharedFS == config.VirtioFS || q.config.FileBackedMemRootDir != "" {
-		target = q.qemuConfig.Memory.Path
-		memoryBack = "memory-backend-file"
-	}
-	if q.qemuConfig.Knobs.MemShared {
-		share = true
-	}
+
+	share, target, memoryBack := q.getMemArgs()
 	err = q.qmpMonitorCh.qmp.ExecHotplugMemory(q.qmpMonitorCh.ctx, memoryBack, "mem"+strconv.Itoa(memDev.slot), target, memDev.sizeMB, share)
 	if err != nil {
 		q.Logger().WithError(err).Error("hotplug memory")
@@ -1661,6 +1701,17 @@ func (q *qemu) resizeMemory(reqMemMB uint32, memoryBlockSizeMB uint32, probe boo
 		return 0, memoryDevice{}, err
 	}
 	var addMemDevice memoryDevice
+	if q.config.VirtioMem && currentMemory != reqMemMB {
+		q.Logger().WithField("hotplug", "memory").Debugf("resize memory from %dMB to %dMB", currentMemory, reqMemMB)
+		sizeByte := (reqMemMB - q.config.MemorySize) * 1024 * 1024
+		err = q.qmpMonitorCh.qmp.ExecQomSet(q.qmpMonitorCh.ctx, "virtiomem0", "requested-size", uint64(sizeByte))
+		if err != nil {
+			return 0, memoryDevice{}, err
+		}
+		q.state.HotpluggedMemory = int(sizeByte / 1024 / 1024)
+		return reqMemMB, memoryDevice{}, nil
+	}
+
 	switch {
 	case currentMemory < reqMemMB:
 		//hotplug