path: root/resources/libraries/python/QemuUtils.py

# Copyright (c) 2018 Cisco and/or its affiliates.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""QEMU utilities library."""

from time import time, sleep
import json

from robot.api import logger

from resources.libraries.python.ssh import SSH, SSHTimeout
from resources.libraries.python.constants import Constants
from resources.libraries.python.topology import NodeType, Topology


class QemuUtils(object):
    """QEMU utilities."""

    def __init__(self, qemu_id=1):
        self._qemu_id = qemu_id
        # Path to QEMU binary. Use x86_64 by default
        self._qemu_path = '/usr/bin/'
        self._qemu_bin = 'qemu-system-x86_64'
        # QEMU Machine Protocol socket
        self._qmp_sock = '/tmp/qmp{0}.sock'.format(self._qemu_id)
        # QEMU Guest Agent socket
        self._qga_sock = '/tmp/qga{0}.sock'.format(self._qemu_id)
        # QEMU PID file
        self._pid_file = '/tmp/qemu{0}.pid'.format(self._qemu_id)
        self._qemu_opt = {}
        # Default 1 CPU.
        self._qemu_opt['smp'] = '-smp 1,sockets=1,cores=1,threads=1'
        # Daemonize the QEMU process after initialization. Default one
        # management interface.
        self._qemu_opt['options'] = '-cpu host -daemonize -enable-kvm ' \
            '-machine pc,accel=kvm,usb=off,mem-merge=off ' \
            '-net nic,macaddr=52:54:00:00:{0:02x}:ff -balloon none'\
            .format(self._qemu_id)
        self._qemu_opt['ssh_fwd_port'] = 10021 + qemu_id
        # Default serial console port
        self._qemu_opt['serial_port'] = 4555 + qemu_id
        # Default 512MB virtual RAM
        self._qemu_opt['mem_size'] = 512
        # Default huge page mount point, required for Vhost-user interfaces.
        self._qemu_opt['huge_mnt'] = '/mnt/huge'
        # Default do not allocate huge pages.
        self._qemu_opt['huge_allocate'] = False
        # Default image for CSIT virl setup
        self._qemu_opt['disk_image'] = '/var/lib/vm/vhost-nested.img'
        # VM node info dict
        self._vm_info = {
            'type': NodeType.VM,
            'port': self._qemu_opt['ssh_fwd_port'],
            'username': 'cisco',
            'password': 'cisco',
            'interfaces': {},
        }
        # Virtio queue count
        self._qemu_opt['queues'] = 1
        self._vhost_id = 0
        self._ssh = None
        self._node = None
        self._socks = [self._qmp_sock, self._qga_sock]

    def qemu_set_path(self, path):
        """Set binary path for QEMU.

        :param path: Absolute path in filesystem.
        :type path: str
        """
        self._qemu_path = path

    def qemu_set_smp(self, cpus, cores, threads, sockets):
        """Set SMP option for QEMU.

        :param cpus: Number of CPUs.
        :param cores: Number of CPU cores on one socket.
        :param threads: Number of threads on one CPU core.
        :param sockets: Number of discrete sockets in the system.
        :type cpus: int
        :type cores: int
        :type threads: int
        :type sockets: int
        """
        self._qemu_opt['smp'] = '-smp {},cores={},threads={},sockets={}'.format(
            cpus, cores, threads, sockets)

    def qemu_set_ssh_fwd_port(self, fwd_port):
        """Set host port for guest SSH forwarding.

        :param fwd_port: Port number on host for guest SSH forwarding.
        :type fwd_port: int
        """
        self._qemu_opt['ssh_fwd_port'] = fwd_port
        self._vm_info['port'] = fwd_port

    def qemu_set_serial_port(self, port):
        """Set serial console port.

        :param port: Serial console port.
        :type port: int
        """
        self._qemu_opt['serial_port'] = port

    def qemu_set_mem_size(self, mem_size):
        """Set virtual RAM size.

        :param mem_size: RAM size in Mega Bytes.
        :type mem_size: int
        """
        self._qemu_opt['mem_size'] = int(mem_size)

    def qemu_set_huge_mnt(self, huge_mnt):
        """Set hugefile mount point.

        :param huge_mnt: System hugefile mount point.
        :type huge_mnt: int
        """
        self._qemu_opt['huge_mnt'] = huge_mnt

    def qemu_set_huge_allocate(self):
        """Set flag to allocate more huge pages if needed."""
        self._qemu_opt['huge_allocate'] = True

    def qemu_set_disk_image(self, disk_image):
        """Set disk image.

        :param disk_image: Path of the disk image.
        :type disk_image: str
        """
        self._qemu_opt['disk_image'] = disk_image

    def qemu_set_affinity(self, *host_cpus):
        """Set qemu affinity by getting thread PIDs via QMP and taskset to list
        of CPU cores.

        :param host_cpus: List of CPU cores.
        :type host_cpus: list
        """
        qemu_cpus = self._qemu_qmp_exec('query-cpus')['return']

        if len(qemu_cpus) != len(host_cpus):
            logger.debug('Host CPU count {0}, Qemu Thread count {1}'.format(
                len(host_cpus), len(qemu_cpus)))
            raise ValueError('Host CPU count must match Qemu Thread count')

        for qemu_cpu, host_cpu in zip(qemu_cpus, host_cpus):
            cmd = 'taskset -pc {0} {1}'.format(host_cpu, qemu_cpu['thread_id'])
            (ret_code, _, stderr) = self._ssh.exec_command_sudo(cmd)
            if int(ret_code) != 0:
                logger.debug('Set affinity failed {0}'.format(stderr))
                raise RuntimeError('Set affinity failed on {0}'.format(
                    self._node['host']))

    def qemu_set_scheduler_policy(self):
        """Set scheduler policy to SCHED_RR with priority 1 for all Qemu CPU
        processes.

        :raises RuntimeError: Set scheduler policy failed.
        """
        qemu_cpus = self._qemu_qmp_exec('query-cpus')['return']

        for qemu_cpu in qemu_cpus:
            cmd = 'chrt -r -p 1 {0}'.format(qemu_cpu['thread_id'])
            (ret_code, _, stderr) = self._ssh.exec_command_sudo(cmd)
            if int(ret_code) != 0:
                logger.debug('Set SCHED_RR failed {0}'.format(stderr))
                raise RuntimeError('Set SCHED_RR failed on {0}'.format(
                    self._node['host']))

    def qemu_set_node(self, node):
        """Set node to run QEMU on.

        :param node: Node to run QEMU on.
        :type node: dict
        """
        self._node = node
        self._ssh = SSH()
        self._ssh.connect(node)
        self._vm_info['host'] = node['host']

        arch = Topology.get_node_arch(node)
        self._qemu_bin = 'qemu-system-{arch}'.format(arch=arch)

    def qemu_add_vhost_user_if(self, socket, server=True, mac=None,
                               jumbo_frames=False):
        """Add Vhost-user interface.

        :param socket: Path of the unix socket.
        :param server: If True the socket shall be a listening socket.
        :param mac: Vhost-user interface MAC address (optional, otherwise is
            used auto-generated MAC 52:54:00:00:xx:yy).
        :param jumbo_frames: Set True if jumbo frames are used in the test.
        :type socket: str
        :type server: bool
        :type mac: str
        :type jumbo_frames: bool
        """
        self._vhost_id += 1
        # Create unix socket character device.
        chardev = ' -chardev socket,id=char{0},path={1}'.format(self._vhost_id,
                                                                socket)
        if server is True:
            chardev += ',server'
        self._qemu_opt['options'] += chardev
        # Create Vhost-user network backend.
        netdev = (' -netdev vhost-user,id=vhost{0},chardev=char{0},queues={1}'
                  .format(self._vhost_id, self._qemu_opt['queues']))
        self._qemu_opt['options'] += netdev
        # If MAC is not specified use auto-generated MAC address based on
        # template 52:54:00:00:<qemu_id>:<vhost_id>, e.g. vhost1 MAC of QEMU
        #  with ID 1 is 52:54:00:00:01:01
        if mac is None:
            mac = '52:54:00:00:{0:02x}:{1:02x}'.\
                format(self._qemu_id, self._vhost_id)
        extend_options = 'mq=on,csum=off,gso=off,guest_tso4=off,'\
            'guest_tso6=off,guest_ecn=off'
        if jumbo_frames:
            extend_options += ",mrg_rxbuf=on"
        else:
            extend_options += ",mrg_rxbuf=off"
        # Create Virtio network device.
        device = ' -device virtio-net-pci,netdev=vhost{0},mac={1},{2}'.format(
            self._vhost_id, mac, extend_options)
        self._qemu_opt['options'] += device
        # Add interface MAC and socket to the node dict
        if_data = {'mac_address': mac, 'socket': socket}
        if_name = 'vhost{}'.format(self._vhost_id)
        self._vm_info['interfaces'][if_name] = if_data
        # Add socket to the socket list
        self._socks.append(socket)

    def _qemu_qmp_exec(self, cmd):
        """Execute QMP command.

        QMP is JSON based protocol which allows to control QEMU instance.

        :param cmd: QMP command to execute.
        :type cmd: str
        :returns: Command output in python representation of JSON format. The
            { "return": {} } response is QMP's success response. An error
            response will contain the "error" keyword instead of "return".
        """
        # To enter command mode, the qmp_capabilities command must be issued.
        qmp_cmd = 'echo "{ \\"execute\\": \\"qmp_capabilities\\" }' \
                  '{ \\"execute\\": \\"' + cmd + \
                  '\\" }" | sudo -S socat - UNIX-CONNECT:' + self._qmp_sock

        (ret_code, stdout, stderr) = self._ssh.exec_command(qmp_cmd)
        if int(ret_code) != 0:
            logger.debug('QMP execute failed {0}'.format(stderr))
            raise RuntimeError('QMP execute "{0}"'
                               ' failed on {1}'.format(cmd, self._node['host']))
        logger.trace(stdout)
        # Skip capabilities negotiation messages.
        out_list = stdout.splitlines()
        if len(out_list) < 3:
            raise RuntimeError('Invalid QMP output on {0}'.format(
                self._node['host']))
        return json.loads(out_list[2])

    def _qemu_qga_flush(self):
        """Flush the QGA parser state
        """
        qga_cmd = '(printf "\xFF"; sleep 1) | sudo -S socat - UNIX-CONNECT:' + \
                  self._qga_sock
        #TODO: probably need something else
        (ret_code, stdout, stderr) = self._ssh.exec_command(qga_cmd)
        if int(ret_code) != 0:
            logger.debug('QGA execute failed {0}'.format(stderr))
            raise RuntimeError('QGA execute "{0}" '
                               'failed on {1}'.format(qga_cmd,
                                                      self._node['host']))
        logger.trace(stdout)
        if not stdout:
            return {}
        return json.loads(stdout.split('\n', 1)[0])

    def _qemu_qga_exec(self, cmd):
        """Execute QGA command.

        QGA provide access to a system-level agent via standard QMP commands.

        :param cmd: QGA command to execute.
        :type cmd: str
        """
        qga_cmd = '(echo "{ \\"execute\\": \\"' + \
                  cmd + \
                  '\\" }"; sleep 1) | sudo -S socat - UNIX-CONNECT:' + \
                  self._qga_sock
        (ret_code, stdout, stderr) = self._ssh.exec_command(qga_cmd)
        if int(ret_code) != 0:
            logger.debug('QGA execute failed {0}'.format(stderr))
            raise RuntimeError('QGA execute "{0}"'
                               ' failed on {1}'.format(cmd, self._node['host']))
        logger.trace(stdout)
        if not stdout:
            return {}
        return json.loads(stdout.split('\n', 1)[0])

    def _wait_until_vm_boot(self, timeout=60):
        """Wait until QEMU VM is booted.

        First try to flush qga until there is output.
        Then ping QEMU guest agent each 5s until VM booted or timeout.

        :param timeout: Waiting timeout in seconds (optional, default 60s).
        :type timeout: int
        """
        start = time()
        while True:
            if time() - start > timeout:
                raise RuntimeError('timeout, VM {0} not booted on {1}'.format(
                    self._qemu_opt['disk_image'], self._node['host']))
            out = None
            try:
                out = self._qemu_qga_flush()
            except ValueError:
                logger.trace('QGA qga flush unexpected output {}'.format(out))
            # Empty output - VM not booted yet
            if not out:
                sleep(5)
            else:
                break
        while True:
            if time() - start > timeout:
                raise RuntimeError('timeout, VM {0} not booted on {1}'.format(
                    self._qemu_opt['disk_image'], self._node['host']))
            out = None
            try:
                out = self._qemu_qga_exec('guest-ping')
            except ValueError:
                logger.trace('QGA guest-ping unexpected output {}'.format(out))
            # Empty output - VM not booted yet
            if not out:
                sleep(5)
            # Non-error return - VM booted
            elif out.get('return') is not None:
                break
            # Skip error and wait
            elif out.get('error') is not None:
                sleep(5)
            else:
                # If there is an unexpected output from QGA guest-info, try
                # again until timeout.
                logger.trace('QGA guest-ping unexpected output {}'.format(out))

        logger.trace('VM {0} booted on {1}'.format(self._qemu_opt['disk_image'],
                                                   self._node['host']))

    def _update_vm_interfaces(self):
        """Update interface names in VM node dict."""
        # Send guest-network-get-interfaces command via QGA, output example:
        # {"return": [{"name": "eth0", "hardware-address": "52:54:00:00:04:01"},
        # {"name": "eth1", "hardware-address": "52:54:00:00:04:02"}]}
        out = self._qemu_qga_exec('guest-network-get-interfaces')
        interfaces = out.get('return')
        mac_name = {}
        if not interfaces:
            raise RuntimeError('Get VM {0} interface list failed on {1}'.format(
                self._qemu_opt['disk_image'], self._node['host']))
        # Create MAC-name dict
        for interface in interfaces:
            if 'hardware-address' not in interface:
                continue
            mac_name[interface['hardware-address']] = interface['name']
        # Match interface by MAC and save interface name
        for interface in self._vm_info['interfaces'].values():
            mac = interface.get('mac_address')
            if_name = mac_name.get(mac)
            if if_name is None:
                logger.trace('Interface name for MAC {} not found'.format(mac))
            else:
                interface['name'] = if_name

    def _huge_page_check(self, allocate=False):
        """Huge page check."""
        huge_mnt = self._qemu_opt.get('huge_mnt')
        mem_size = self._qemu_opt.get('mem_size')

        # Get huge pages information
        huge_size = self._get_huge_page_size()
        huge_free = self._get_huge_page_free(huge_size)
        huge_total = self._get_huge_page_total(huge_size)

        # Check if memory reqested by qemu is available on host
        if (mem_size * 1024) > (huge_free * huge_size):
            # If we want to allocate hugepage dynamically
            if allocate:
                mem_needed = abs((huge_free * huge_size) - (mem_size * 1024))
                huge_to_allocate = ((mem_needed / huge_size) * 2) + huge_total
                max_map_count = huge_to_allocate*4
                # Increase maximum number of memory map areas a process may have
                cmd = 'echo "{0}" | sudo tee /proc/sys/vm/max_map_count'.format(
                    max_map_count)
                (ret_code, _, stderr) = self._ssh.exec_command_sudo(cmd)
                # Increase hugepage count
                cmd = 'echo "{0}" | sudo tee /proc/sys/vm/nr_hugepages'.format(
                    huge_to_allocate)
                (ret_code, _, stderr) = self._ssh.exec_command_sudo(cmd)
                if int(ret_code) != 0:
                    logger.debug('Mount huge pages failed {0}'.format(stderr))
                    raise RuntimeError('Mount huge pages failed on {0}'.format(
                        self._node['host']))
            # If we do not want to allocate dynamicaly end with error
            else:
                raise RuntimeError(
                    'Not enough free huge pages: {0}, '
                    '{1} MB'.format(huge_free, huge_free * huge_size)
                )
        # Check if huge pages mount point exist
        has_huge_mnt = False
        (_, output, _) = self._ssh.exec_command('cat /proc/mounts')
        for line in output.splitlines():
            # Try to find something like:
            # none /mnt/huge hugetlbfs rw,relatime,pagesize=2048k 0 0
            mount = line.split()
            if mount[2] == 'hugetlbfs' and mount[1] == huge_mnt:
                has_huge_mnt = True
                break
        # If huge page mount point not exist create one
        if not has_huge_mnt:
            cmd = 'mkdir -p {0}'.format(huge_mnt)
            (ret_code, _, stderr) = self._ssh.exec_command_sudo(cmd)
            if int(ret_code) != 0:
                logger.debug('Create mount dir failed: {0}'.format(stderr))
                raise RuntimeError('Create mount dir failed on {0}'.format(
                    self._node['host']))
            cmd = 'mount -t hugetlbfs -o pagesize=2048k none {0}'.format(
                huge_mnt)
            (ret_code, _, stderr) = self._ssh.exec_command_sudo(cmd)
            if int(ret_code) != 0:
                logger.debug('Mount huge pages failed {0}'.format(stderr))
                raise RuntimeError('Mount huge pages failed on {0}'.format(
                    self._node['host']))

    def _get_huge_page_size(self):
        """Get default size of huge pages in system.

        :returns: Default size of free huge pages in system.
        :rtype: int
        :raises RuntimeError: If reading failed for three times.
        """
        # TODO: remove to dedicated library
        cmd_huge_size = "grep Hugepagesize /proc/meminfo | awk '{ print $2 }'"
        for _ in range(3):
            (ret, out, _) = self._ssh.exec_command_sudo(cmd_huge_size)
            if ret == 0:
                try:
                    huge_size = int(out)
                except ValueError:
                    logger.trace('Reading huge page size information failed')
                else:
                    break
        else:
            raise RuntimeError('Getting huge page size information failed.')
        return huge_size

    def _get_huge_page_free(self, huge_size):
        """Get total number of huge pages in system.

        :param huge_size: Size of hugepages.
        :type huge_size: int
        :returns: Number of free huge pages in system.
        :rtype: int
        :raises RuntimeError: If reading failed for three times.
        """
        # TODO: add numa aware option
        # TODO: remove to dedicated library
        cmd_huge_free = 'cat /sys/kernel/mm/hugepages/hugepages-{0}kB/'\
            'free_hugepages'.format(huge_size)
        for _ in range(3):
            (ret, out, _) = self._ssh.exec_command_sudo(cmd_huge_free)
            if ret == 0:
                try:
                    huge_free = int(out)
                except ValueError:
                    logger.trace('Reading free huge pages information failed')
                else:
                    break
        else:
            raise RuntimeError('Getting free huge pages information failed.')
        return huge_free

    def _get_huge_page_total(self, huge_size):
        """Get total number of huge pages in system.

        :param huge_size: Size of hugepages.
        :type huge_size: int
        :returns: Total number of huge pages in system.
        :rtype: int
        :raises RuntimeError: If reading failed for three times.
        """
        # TODO: add numa aware option
        # TODO: remove to dedicated library
        cmd_huge_total = 'cat /sys/kernel/mm/hugepages/hugepages-{0}kB/'\
            'nr_hugepages'.format(huge_size)
        for _ in range(3):
            (ret, out, _) = self._ssh.exec_command_sudo(cmd_huge_total)
            if ret == 0:
                try:
                    huge_total = int(out)
                except ValueError:
                    logger.trace('Reading total huge pages information failed')
                else:
                    break
        else:
            raise RuntimeError('Getting total huge pages information failed.')
        return huge_total

    def qemu_start(self):
        """Start QEMU and wait until VM boot.

        .. note:: First set at least node to run QEMU on.
        .. warning:: Starts only one VM on the node.

        :returns: VM node info.
        :rtype: dict
        """
        # Qemu binary path
        bin_path = '{0}{1}'.format(self._qemu_path, self._qemu_bin)

        # SSH forwarding
        ssh_fwd = '-net user,hostfwd=tcp::{0}-:22'.format(
            self._qemu_opt.get('ssh_fwd_port'))
        # Memory and huge pages
        mem = '-object memory-backend-file,id=mem,size={0}M,mem-path={1},' \
            'share=on -m {0} -numa node,memdev=mem'.format(
                self._qemu_opt.get('mem_size'), self._qemu_opt.get('huge_mnt'))

        # By default check only if hugepages are available.
        # If 'huge_allocate' is set to true try to allocate as well.
        self._huge_page_check(allocate=self._qemu_opt.get('huge_allocate'))

        # Disk option
        drive = '-drive file={0},format=raw,cache=none,if=virtio'.format(
            self._qemu_opt.get('disk_image'))
        # Setup QMP via unix socket
        qmp = '-qmp unix:{0},server,nowait'.format(self._qmp_sock)
        # Setup serial console
        serial = '-chardev socket,host=127.0.0.1,port={0},id=gnc0,server,' \
            'nowait -device isa-serial,chardev=gnc0'.format(
                self._qemu_opt.get('serial_port'))
        # Setup QGA via chardev (unix socket) and isa-serial channel
        qga = '-chardev socket,path={0},server,nowait,id=qga0 ' \
            '-device isa-serial,chardev=qga0'.format(self._qga_sock)
        # Graphic setup
        graphic = '-monitor none -display none -vga none'
        # PID file
        pid = '-pidfile {}'.format(self._pid_file)

        # Run QEMU
        cmd = '{0} {1} {2} {3} {4} {5} {6} {7} {8} {9} {10}'.format(bin_path,
            self._qemu_opt.get('smp'), mem, ssh_fwd,
            self._qemu_opt.get('options'), drive, qmp, serial, qga, graphic,
            pid)
        try:
            (ret_code, _, _) = self._ssh.exec_command_sudo(cmd, timeout=300)
            if int(ret_code) != 0:
                raise RuntimeError('QEMU start failed on {0}'.format(
                    self._node['host']))
            # Wait until VM boot
            self._wait_until_vm_boot()
        except (RuntimeError, SSHTimeout):
            self.qemu_kill_all()
            self.qemu_clear_socks()
            raise
        logger.trace('QEMU started successfully.')
        # Update interface names in VM node dict
        self._update_vm_interfaces()
        # Return VM node dict
        return self._vm_info

    def qemu_quit(self):
        """Quit the QEMU emulator."""
        out = self._qemu_qmp_exec('quit')
        err = out.get('error')
        if err is not None:
            raise RuntimeError('QEMU quit failed on {0}, error: {1}'.format(
                self._node['host'], json.dumps(err)))

    def qemu_system_powerdown(self):
        """Power down the system (if supported)."""
        out = self._qemu_qmp_exec('system_powerdown')
        err = out.get('error')
        if err is not None:
            raise RuntimeError(
                'QEMU system powerdown failed on {0}, '
                'error: {1}'.format(self._node['host'], json.dumps(err))
            )

    def qemu_system_reset(self):
        """Reset the system."""
        out = self._qemu_qmp_exec('system_reset')
        err = out.get('error')
        if err is not None:
            raise RuntimeError(
                'QEMU system reset failed on {0}, '
                'error: {1}'.format(self._node['host'], json.dumps(err)))

    def qemu_kill(self):
        """Kill qemu process."""
        # Note: in QEMU start phase there are 3 QEMU processes because we
        # daemonize QEMU
        self._ssh.exec_command_sudo('chmod +r {}'.format(self._pid_file))
        self._ssh.exec_command_sudo('kill -SIGKILL $(cat {})'
                                    .format(self._pid_file))
        # Delete PID file
        cmd = 'rm -f {}'.format(self._pid_file)
        self._ssh.exec_command_sudo(cmd)

    def qemu_kill_all(self, node=None):
        """Kill all qemu processes on DUT node if specified.

        :param node: Node to kill all QEMU processes on.
        :type node: dict
        """
        if node:
            self.qemu_set_node(node)
        self._ssh.exec_command_sudo('pkill -SIGKILL qemu')

    def qemu_clear_socks(self):
        """Remove all sockets created by QEMU."""
        # If serial console port still open kill process
        cmd = 'fuser -k {}/tcp'.format(self._qemu_opt.get('serial_port'))
        self._ssh.exec_command_sudo(cmd)
        # Delete all created sockets
        for sock in self._socks:
            cmd = 'rm -f {}'.format(sock)
            self._ssh.exec_command_sudo(cmd)

    def qemu_system_status(self):
        """Return current VM status.

        VM should be in following status:

            - debug: QEMU running on a debugger
            - finish-migrate: paused to finish the migration process
            - inmigrate: waiting for an incoming migration
            - internal-error: internal error has occurred
            - io-error: the last IOP has failed
            - paused: paused
            - postmigrate: paused following a successful migrate
            - prelaunch: QEMU was started with -S and guest has not started
            - restore-vm: paused to restore VM state
            - running: actively running
            - save-vm: paused to save the VM state
            - shutdown: shut down (and -no-shutdown is in use)
            - suspended: suspended (ACPI S3)
            - watchdog: watchdog action has been triggered
            - guest-panicked: panicked as a result of guest OS panic

        :returns: VM status.
        :rtype: str
        """
        out = self._qemu_qmp_exec('query-status')
        ret = out.get('return')
        if ret is not None:
            return ret.get('status')
        else:
            err = out.get('error')
            raise RuntimeError(
                'QEMU query-status failed on {0}, '
                'error: {1}'.format(self._node['host'], json.dumps(err)))

    @staticmethod
    def build_qemu(node, force_install=False, apply_patch=False):
        """Build QEMU from sources.

        :param node: Node to build QEMU on.
        :param force_install: If True, then remove previous build.
        :param apply_patch: If True, then apply patches from qemu_patches dir.
        :type node: dict
        :type force_install: bool
        :type apply_patch: bool
        :raises RuntimeError: If building QEMU failed.
        """
        ssh = SSH()
        ssh.connect(node)

        directory = ' --directory={0}'.format(Constants.QEMU_INSTALL_DIR)
        if apply_patch:
            directory += '-patch'
        else:
            directory += '-base'
        version = ' --version={0}'.format(Constants.QEMU_INSTALL_VERSION)
        force = ' --force' if force_install else ''
        patch = ' --patch' if apply_patch else ''
        arch = Topology.get_node_arch(node)
        target_list = ' --target-list={0}-softmmu'.format(arch)

        (ret_code, stdout, stderr) = \
            ssh.exec_command(
                "sudo -E sh -c '{0}/{1}/qemu_build.sh{2}{3}{4}{5}{6}'"\
                .format(Constants.REMOTE_FW_DIR, Constants.RESOURCES_LIB_SH,
                        version, directory, force, patch, target_list), 1000)

        if int(ret_code) != 0:
            logger.debug('QEMU build failed {0}'.format(stdout + stderr))
            raise RuntimeError('QEMU build failed on {0}'.format(node['host']))