diff --git a/src/runtime/virtcontainers/fs_share.go b/src/runtime/virtcontainers/fs_share.go
new file mode 100644
index 0000000000..fa8374c3b8
--- /dev/null
+++ b/src/runtime/virtcontainers/fs_share.go
@@ -0,0 +1,77 @@
+// Copyright (c) 2022 Apple Inc.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+package virtcontainers
+
+import (
+	"context"
+
+	"github.com/kata-containers/kata-containers/src/runtime/virtcontainers/pkg/agent/protocols/grpc"
+)
+
+// fsShareTracingTags defines tags for the trace span
+var fsShareTracingTags = map[string]string{
+	"source":    "runtime",
+	"package":   "virtcontainers",
+	"subsystem": "fs_share",
+}
+
+// SharedFile represents the outcome of a host filesystem sharing
+// operation.
+type SharedFile struct {
+	storage   *grpc.Storage
+	guestPath string
+}
+
+type FilesystemSharer interface {
+	// Prepare will set the host filesystem up, making it ready
+	// to share container files and directories with the guest.
+	// It will be called before any container is running.
+	//
+	// For example, the Linux implementation would create and
+	// prepare the host shared folders, and also make all
+	// sandbox mounts ready to be shared.
+	//
+	// Implementation of this method must be idempotent and be
+	// ready to potentially be called several times in a row,
+	// without symmetric calls to Cleanup in between.
+	Prepare(context.Context) error
+
+	// Cleanup cleans the host filesystem up from the initial
+	// setup created by Prepare.
+	// It will be called after all containers are terminated.
+	//
+	// Implementation of this method must be idempotent and be
+	// ready to potentially be called several times in a row,
+	// without symmetric calls to Prepare in between.
+	Cleanup(context.Context) error
+
+	// ShareFile shares a file (a regular file or a directory)
+	// from the host filesystem with a container running in the
+	// guest. The host file to be shared is described by the
+	// Mount argument.
+	// This method should be called for each container file to
+	// be shared with the guest.
+	//
+	// The returned SharedFile pointer describes how the file
+	// should be shared between the host and the guest. If it
+	// is nil, then the shared filed described by the Mount
+	// argument will be ignored by the guest, i.e. it will NOT
+	// be shared with the guest.
+	ShareFile(context.Context, *Container, *Mount) (*SharedFile, error)
+
+	// UnshareFile stops sharing a container file, described by
+	// the Mount argument.
+	UnshareFile(context.Context, *Container, *Mount) error
+
+	// ShareRootFilesystem shares a container bundle rootfs with
+	// the Kata guest, allowing the kata agent to eventually start
+	// the container from that shared rootfs.
+	ShareRootFilesystem(context.Context, *Container) (*SharedFile, error)
+
+	// UnshareRootFilesystem stops sharing a container bundle
+	// rootfs.
+	UnshareRootFilesystem(context.Context, *Container) error
+}