config: add shared_fs option

Add a config option to select between virtio-9p and virtiofs.  This
option currently has no effect and will be used in a later patch.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Makefile

@@ -156,6 +156,7 @@ DEFAULTEXPFEATURES := []
 DEFENTROPYSOURCE := /dev/urandom
 
 DEFDISABLEBLOCK := false
+DEFSHAREDFS := virtio-9p
 DEFENABLEIOTHREADS := false
 DEFENABLEMEMPREALLOC := false
 DEFENABLEHUGEPAGES := false
@@ -320,6 +321,7 @@ USER_VARS += DEFAULTEXPFEATURES
 USER_VARS += DEFDISABLEBLOCK
 USER_VARS += DEFBLOCKSTORAGEDRIVER_FC
 USER_VARS += DEFBLOCKSTORAGEDRIVER_QEMU
+USER_VARS += DEFSHAREDFS
 USER_VARS += DEFENABLEIOTHREADS
 USER_VARS += DEFENABLEMEMPREALLOC
 USER_VARS += DEFENABLEHUGEPAGES
@@ -456,6 +458,7 @@ $(GENERATED_FILES): %: %.in $(MAKEFILE_LIST) VERSION .git-commit
 		-e "s|@DEFDISABLEBLOCK@|$(DEFDISABLEBLOCK)|g" \
 		-e "s|@DEFBLOCKSTORAGEDRIVER_FC@|$(DEFBLOCKSTORAGEDRIVER_FC)|g" \
 		-e "s|@DEFBLOCKSTORAGEDRIVER_QEMU@|$(DEFBLOCKSTORAGEDRIVER_QEMU)|g" \
+		-e "s|@DEFSHAREDFS@|$(DEFSHAREDFS)|g" \
 		-e "s|@DEFENABLEIOTHREADS@|$(DEFENABLEIOTHREADS)|g" \
 		-e "s|@DEFENABLEMEMPREALLOC@|$(DEFENABLEMEMPREALLOC)|g" \
 		-e "s|@DEFENABLEHUGEPAGES@|$(DEFENABLEHUGEPAGES)|g" \

cli/config/configuration-qemu.toml.in

@@ -97,6 +97,11 @@ default_memory = @DEFMEMSZ@
 # 9pfs is used instead to pass the rootfs.
 disable_block_device_use = @DEFDISABLEBLOCK@
 
+# Shared file system type:
+#   - virtio-9p (default)
+#   - virtio-fs
+shared_fs = "@DEFSHAREDFS@"
+
 # Block storage driver to be used for the hypervisor in case the container
 # rootfs is backed by a block device. This is virtio-scsi, virtio-blk
 # or nvdimm.

pkg/katautils/config.go

@@ -92,6 +92,7 @@ type hypervisor struct {
 	MachineType             string `toml:"machine_type"`
 	BlockDeviceDriver       string `toml:"block_device_driver"`
 	EntropySource           string `toml:"entropy_source"`
+	SharedFS                string `toml:"shared_fs"`
 	BlockDeviceCacheSet     bool   `toml:"block_device_cache_set"`
 	BlockDeviceCacheDirect  bool   `toml:"block_device_cache_direct"`
 	BlockDeviceCacheNoflush bool   `toml:"block_device_cache_noflush"`
@@ -326,6 +327,22 @@ func (h hypervisor) blockDeviceDriver() (string, error) {
 	return "", fmt.Errorf("Invalid hypervisor block storage driver %v specified (supported drivers: %v)", h.BlockDeviceDriver, supportedBlockDrivers)
 }
 
+func (h hypervisor) sharedFS() (string, error) {
+	supportedSharedFS := []string{config.Virtio9P, config.VirtioFS}
+
+	if h.SharedFS == "" {
+		return config.Virtio9P, nil
+	}
+
+	for _, fs := range supportedSharedFS {
+		if fs == h.SharedFS {
+			return h.SharedFS, nil
+		}
+	}
+
+	return "", fmt.Errorf("Invalid hypervisor shared file system %v specified (supported file systems: %v)", h.SharedFS, supportedSharedFS)
+}
+
 func (h hypervisor) msize9p() uint32 {
 	if h.Msize9p == 0 {
 		return defaultMsize9p
@@ -521,6 +538,11 @@ func newQemuHypervisorConfig(h hypervisor) (vc.HypervisorConfig, error) {
 		return vc.HypervisorConfig{}, err
 	}
 
+	sharedFS, err := h.sharedFS()
+	if err != nil {
+		return vc.HypervisorConfig{}, err
+	}
+
 	useVSock := false
 	if h.useVSock() {
 		if utils.SupportsVsocks() {
@@ -548,6 +570,7 @@ func newQemuHypervisorConfig(h hypervisor) (vc.HypervisorConfig, error) {
 		EntropySource:           h.GetEntropySource(),
 		DefaultBridges:          h.defaultBridges(),
 		DisableBlockDeviceUse:   h.DisableBlockDeviceUse,
+		SharedFS:                sharedFS,
 		MemPrealloc:             h.MemPrealloc,
 		HugePages:               h.HugePages,
 		Mlock:                   !h.Swap,

virtcontainers/device/config/config.go

@@ -52,6 +52,14 @@ const (
 	Nvdimm = "nvdimm"
 )
 
+const (
+	// Virtio9P means use virtio-9p for the shared file system
+	Virtio9P = "virtio-9p"
+
+	// VirtioFS means use virtio-fs for the shared file system
+	VirtioFS = "virtio-fs"
+)
+
 // Defining these as a variable instead of a const, to allow
 // overriding this in the tests.
 

virtcontainers/documentation/api/1.0/api.md

@@ -138,6 +138,11 @@ type HypervisorConfig struct {
 	// DisableBlockDeviceUse disallows a block device from being used.
 	DisableBlockDeviceUse bool
 
+	// Shared file system type:
+	//   - virtio-9p (default)
+	//   - virtio-fs
+	SharedFS string
+
 	// KernelParams are additional guest kernel parameters.
 	KernelParams []Param
 

virtcontainers/hypervisor.go

@@ -215,6 +215,11 @@ type HypervisorConfig struct {
 	// entropy (/dev/random, /dev/urandom or real hardware RNG device)
 	EntropySource string
 
+	// Shared file system type:
+	//   - virtio-9p (default)
+	//   - virtio-fs
+	SharedFS 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,