vm_tools/init/vm_concierge.conf

# Copyright 2017 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

description    "Start the VM concierge service"
author         "chromium-os-dev@chromium.org"

# Start the VM concierge service, which is responsible for managing all the
# VMs running in the system.

# If we are using plugin VMs then we will start concierge together with the
# dispatcher, otherwise concierge will be started explicitly.
start on starting vmplugin_dispatcher
stop on stopping ui
respawn
expect fork

# Give any running VMs enough time to attempt an orderly shutdown.
kill timeout 30

pre-start script
  # Make sure the vsock module is loaded.
  modprobe -q vhost-vsock

  # Create the runtime directory.
  mkdir -p /run/vm
  chown crosvm:crosvm /run/vm

  # Create the runtime directory for plugin VMs.
  mkdir -p /run/pvm
  chmod 770 /run/pvm
  chown pluginvm:crosvm /run/pvm

  # Create the cicerone runtime directory, we need to do this here because it
  # has to be mounted into the namespace for concierge.
  mkdir -p /run/vm_cicerone
  chown vm_cicerone:vm_cicerone /run/vm_cicerone

  # Create the directory for UNIX socket communication with plugin VMs.
  mkdir -p /run/vm_cicerone/client
  chmod 770 /run/vm_cicerone/client
  chown vm_cicerone:crosvm /run/vm_cicerone/client

  # Create the directory for various services that we need to mount in
  # concierge's namespace. Individual service scripts will adjust ownership
  # and permissions as needed.
  mkdir -p /run/camera /run/cups

end script

# Allow the following capabilities:
#
#  CAP_SETGID    for allowing mapping additional gids in user namespaces
#                of jailed children. It will be added to the ambient set
#                by concierge
#  CAP_NET_ADMIN for creating tap devices
#
# /proc is also remounted read-write because crosvm needs to be able to set the
# uid_map and gid_map for its child processes and that needs a writable /proc.
#
# The following mount flags are used below:
#  MS_BIND = 0x1000
#  MS_REC  = 0x4000
#
# -Kslave is applied to propagate imageloader mounts into concierge's mount
# namespace.
exec minijail0 -nplrvd -t -i -I --uts \
     -u crosvm -g crosvm -G \
     -c 'cap_net_admin,cap_setgid+eip' \
     -Kslave \
     -P /mnt/empty \
     -b /,/ \
     -k proc,/proc,proc,0xe \
     -b /sys,/sys \
     -b /dev/chromeos-low-mem \
     -b /dev/log,/dev/log,1 \
     -b /dev/kvm,/dev/kvm,1 \
     -b /dev/net,/dev/net,1 \
     -b /dev/vhost-vsock,/dev/vhost-vsock,1 \
     -b /dev/dri,/dev/dri,1 \
     -k run,/run,tmpfs,0xe \
     -b /run/camera/,,1 \
     -b /run/chrome,/run/chrome,1 \
     -b /run/cras,,1 \
     -b /run/cups,,1 \
     -b /run/dbus,/run/dbus,1 \
     -b /run/pvm,,1 \
     -b /run/vm,/run/vm,1 \
     -b /run/vm_cicerone/client,/run/vm_cicerone/client,1 \
     -k var,/var,tmpfs,0xe,mode=755,size=32M \
     -k empty,/var/empty,tmpfs,0xf,mode=755,size=32M \
     -k /run/imageloader,/run/imageloader,none,0x5000 \
     -k /home,/home,none,0x5000 \
     -- /usr/bin/vm_concierge

# Put the concierge and all VMs it starts in a cpu cgroup.
# Default cpu.shares is 1024. Limit the VMs to 7/8ths of that.
post-start script
  cgroup_dir="/sys/fs/cgroup/cpu/vms"
  mkdir -p "${cgroup_dir}"
  echo $(status | cut -f 4 -d ' ') > "${cgroup_dir}/tasks"
  echo 896 > "${cgroup_dir}/cpu.shares"
end script