Re: [Qemu-devel] [RFC 01/24] qemu.py: Introduce _create_console() method

[Eduardo Habkost <ehabkost@redhat.com>]

On Fri, Apr 20, 2018 at 03:19:28PM -0300, Eduardo Habkost wrote:
> From: Amador Pahim <apahim@redhat.com>
> 
> This patch adds the QEMUMachine._create_console() method, which
> returns a list with the chardev console device arguments to be
> used in the qemu command line.
> 
> Signed-off-by: Amador Pahim <apahim@redhat.com>
> [ehabkost: reword commit message]
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
>  scripts/qemu.py | 49 ++++++++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 44 insertions(+), 5 deletions(-)
> 
> diff --git a/scripts/qemu.py b/scripts/qemu.py
> index 08a3e9af5a..9e9d502543 100644
> --- a/scripts/qemu.py
> +++ b/scripts/qemu.py
> @@ -55,7 +55,7 @@ class QEMUMachine(object):
>  
>      def __init__(self, binary, args=None, wrapper=None, name=None,
>                   test_dir="/var/tmp", monitor_address=None,
> -                 socket_scm_helper=None):
> +                 socket_scm_helper=None, arch=None):
>          '''
>          Initialize a QEMUMachine
>  
> @@ -91,6 +91,10 @@ class QEMUMachine(object):
>          self._test_dir = test_dir
>          self._temp_dir = None
>          self._launched = False
> +        if arch is None:
> +            arch = binary.split('-')[-1]

This is not good.  We don't want a test case to break only
because we renamed a QEMU binary (e.g. RHEL uses
/usr/libexec/qemu-kvm, and I can imagine people using qemu.py to
write test scripts for it).


> +        self._arch = arch
> +        self._console_address = None
>  
>          # just in case logging wasn't configured by the main script:
>          logging.basicConfig()
> @@ -179,6 +183,39 @@ class QEMUMachine(object):
>                  '-mon', 'chardev=mon,mode=control',
>                  '-display', 'none', '-vga', 'none']
>  
> +    def _create_console(self, console_address):
> +        for item in self._args:
> +            for option in ['isa-serial', 'spapr-vty', 'sclpconsole']:
> +                if option in item:
> +                    return []

This is very fragile.  What's the goal of this chunk of code?


> +
> +        chardev = 'socket,id=console,{address},server,nowait'
> +        if console_address is None:
> +            console_address = tempfile.mktemp()
> +            chardev = chardev.format(address='path=%s' %
> +                                     console_address)
> +        elif isinstance(console_address, tuple):
> +            chardev = chardev.format(address='host=%s,port=%s' %
> +                                     (console_address[0],
> +                                     console_address[1]))
> +        else:
> +            chardev = chardev.format(address='path=%s' % console_address)
> +
> +        self._console_address = console_address
> +
> +        device = '{dev_type},chardev=console'
> +        if '86' in self._arch:
> +            device = device.format(dev_type='isa-serial')
> +        elif 'ppc' in self._arch:
> +            device = device.format(dev_type='spapr-vty')
> +        elif 's390x' in self._arch:
> +            device = device.format(dev_type='sclpconsole')

Why do we need this? Why isn't -serial enough?


> +        else:
> +            return []
> +
> +        return ['-chardev', chardev,
> +                '-device', device]
> +
>      def _pre_launch(self):
>          self._temp_dir = tempfile.mkdtemp(dir=self._test_dir)
>          if self._monitor_address is not None:
> @@ -206,7 +243,7 @@ class QEMUMachine(object):
>              shutil.rmtree(self._temp_dir)
>              self._temp_dir = None
>  
> -    def launch(self):
> +    def launch(self, console_address=None):
>          """
>          Launch the VM and make sure we cleanup and expose the
>          command line/output in case of exception
> @@ -218,7 +255,7 @@ class QEMUMachine(object):
>          self._iolog = None
>          self._qemu_full_args = None
>          try:
> -            self._launch()
> +            self._launch(console_address)
>              self._launched = True
>          except:
>              self.shutdown()
> @@ -230,12 +267,14 @@ class QEMUMachine(object):
>                  LOG.debug('Output: %r', self._iolog)
>              raise
>  
> -    def _launch(self):
> +    def _launch(self, console_address):
>          '''Launch the VM and establish a QMP connection'''
>          devnull = open(os.path.devnull, 'rb')
>          self._pre_launch()
> +        bargs = self._base_args()
> +        bargs.extend(self._create_console(console_address))
>          self._qemu_full_args = (self._wrapper + [self._binary] +
> -                                self._base_args() + self._args)
> +                                bargs + self.args)
>          self._popen = subprocess.Popen(self._qemu_full_args,
>                                         stdin=devnull,
>                                         stdout=self._qemu_log_file,
> -- 
> 2.14.3
> 

-- 
Eduardo