virtio-fs: add virtio_fs_extra_args for virtiofsd

Since virtio-fs is under active development, more
options will be added increasingly. To avaoid frequent
change on runtime side to handle option changes, use
one mingled arg to ease testing new option/feature of
virtiofsd.

See `virtiofsd -h` for more option details.

Fixes: #1999
Signed-off-by: Eric Ren <renzhen@linux.alibaba.com>

cli/config/configuration-nemu.toml.in

@@ -123,6 +123,14 @@ virtio_fs_cache_size = @DEFVIRTIOFSCACHESIZE@
 #    Metadata, data, and pathname lookup are cached in guest and never expire.
 virtio_fs_cache = "@DEFVIRTIOFSCACHE@"
 
+# Extra args for virtiofsd daemon
+#
+# Format example:
+#   ["-o", "arg1=xxx,arg2", "-o", "hello world", "--arg3=yyy"]
+#
+# see `virtiofsd -h` for possible options.
+virtio_fs_extra_args = @DEFVIRTIOFSEXTRAARGS@
+
 # 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.

cli/config/configuration-qemu.toml.in

@@ -108,6 +108,14 @@ virtio_fs_daemon = "@DEFVIRTIOFSDAEMON@"
 # Default size of DAX cache in MiB
 virtio_fs_cache_size = @DEFVIRTIOFSCACHESIZE@
 
+# Extra args for virtiofsd daemon
+#
+# Format example:
+#   ["-o", "arg1=xxx,arg2", "-o", "hello world", "--arg3=yyy"]
+#
+# see `virtiofsd -h` for possible options.
+virtio_fs_extra_args = @DEFVIRTIOFSEXTRAARGS@
+
 # Cache mode:
 #
 #  - none