Crosvm supports virtio-fs, a shared file system that lets virtual machines access a directory tree on the host. It allows the guest to access files on the host machine. This section will explain how to create a shared directory. You can also find a runnable sample in tools/examples/example_fs.

Creating a Shared Directory on the Host Machine

Run following commands in host machine, to create a shared directory:

mkdir host_shared_dir
crosvm run \
   --shared-dir "$HOST_SHARED_DIR:my_shared_tag:type=fs" \
  ... # usual crosvm args

In the --shared-dir argument:

  • The first field is the directory to be shared ($HOST_SHARED_DIR in this example).
  • The second field is the tag that the VM will use to identify the device (my_shared_tag in this example).
  • The remaining fields are key-value pairs configuring the shared directory.

To see available options, run crosvm run --help.

Mount the Shared Directory in the Guest OS

Next, switch to the guest OS and run the following commands to set up the shared directory:

sudo su
mkdir /tmp/guest_shared_dir
mount -t virtiofs my_shared_tag /tmp/guest_shared_dir

You can now add files to the shared directory. Any files you put in the guest_shared_dir will appear in the host_shared_dir on the host machine, and vice versa.