Re: [PATCH v12 02/19] multi-process: add configure and usage information

[Jag Raman]

> On Dec 4, 2020, at 9:37 AM, Daniel P. Berrangé <berrange@redhat.com> wrote:
> 
> On Tue, Dec 01, 2020 at 03:22:37PM -0500, Jagannathan Raman wrote:
>> From: Elena Ufimtseva <elena.ufimtseva@oracle.com>
>> 
>> Adds documentation explaining the command-line arguments needed
>> to use multi-process. Also adds a python script that illustrates the
>> usage.
>> 
>> Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
>> Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
>> Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
>> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
>> ---
>> docs/multi-process.rst                        | 66 +++++++++++++++++++
>> MAINTAINERS                                   |  1 +
>> tests/multiprocess/multiprocess-lsi53c895a.py | 92 
>> +++++++++++++++++++++++++++
>> 3 files changed, 159 insertions(+)
>> create mode 100644 docs/multi-process.rst
>> create mode 100755 tests/multiprocess/multiprocess-lsi53c895a.py
> 
> 
>> diff --git a/tests/multiprocess/multiprocess-lsi53c895a.py 
>> b/tests/multiprocess/multiprocess-lsi53c895a.py
>> new file mode 100755
>> index 0000000..bfe4f66
>> --- /dev/null
>> +++ b/tests/multiprocess/multiprocess-lsi53c895a.py
>> @@ -0,0 +1,92 @@
>> +#!/usr/bin/env python3
>> +
>> +import urllib.request
>> +import subprocess
>> +import argparse
>> +import socket
>> +import sys
>> +import os
>> +
>> +arch = os.uname()[4]
>> +proc_path = os.path.join(os.getcwd(), '..', '..', 'build', arch+'-softmmu',
>> +                         'qemu-system-'+arch)
>> +
>> +parser = argparse.ArgumentParser(description='Launcher for multi-process 
>> QEMU')
>> +parser.add_argument('--bin', required=False, help='location of QEMU binary',
>> +                    metavar='bin');
>> +args = parser.parse_args()
>> +
>> +if args.bin is not None:
>> +    proc_path = args.bin
>> +
>> +if not os.path.isfile(proc_path):
>> +    sys.exit('QEMU binary not found')
>> +
>> +kernel_path = os.path.join(os.getcwd(), 'vmlinuz')
>> +initrd_path = os.path.join(os.getcwd(), 'initrd')
>> +
>> +proxy_cmd = [ proc_path,                                                    
>> \
>> +              '-name', 'Fedora', '-smp', '4', '-m', '2048', '-cpu', 'host', 
>> \
> 
> I wonder if setting 2 GB of RAM is too large for something that runs by
> default as a test.
> 
>> +              '-object', 'memory-backend-memfd,id=sysmem-file,size=2G',     
>> \
>> +              '-numa', 'node,memdev=sysmem-file',                           
>> \
>> +              '-kernel', kernel_path, '-initrd', initrd_path,               
>> \
>> +              '-vnc', ':0',                                                 
>> \
>> +              '-monitor', 'unix:/home/qemu-sock,server,nowait',             
>> \
>> +            ]
>> +
>> +if arch == 'x86_64':
>> +    print('Downloading images for arch x86_64')
>> +    kernel_url = 'https://dl.fedoraproject.org/pub/fedora/linux/'    \
>> +                 'releases/33/Everything/x86_64/os/images/'          \
>> +                 'pxeboot/vmlinuz'
>> +    initrd_url = 'https://dl.fedoraproject.org/pub/fedora/linux/'    \
>> +                 'releases/33/Everything/x86_64/os/images/'          \
>> +                 'pxeboot/initrd.img'
>> +    proxy_cmd.append('-machine')
>> +    proxy_cmd.append('pc,accel=kvm')
>> +    proxy_cmd.append('-append')
>> +    proxy_cmd.append('rdinit=/bin/bash console=ttyS0 console=tty0')
>> +elif arch == 'aarch64':
>> +    print('Downloading images for arch aarch64')
>> +    kernel_url = 'https://dl.fedoraproject.org/pub/fedora/linux/'    \
>> +                 'releases/33/Everything/aarch64/os/images/'         \
>> +                 'pxeboot/vmlinuz'
>> +    initrd_url = 'https://dl.fedoraproject.org/pub/fedora/linux/'    \
>> +                 'releases/33/Everything/aarch64/os/images/'         \
>> +                 'pxeboot/initrd.img'
>> +    proxy_cmd.append('-machine')
>> +    proxy_cmd.append('virt,gic-version=3')
>> +    proxy_cmd.append('-accel')
>> +    proxy_cmd.append('kvm')
>> +    proxy_cmd.append('-append')
>> +    proxy_cmd.append('rdinit=/bin/bash')
>> +else:
>> +    sys.exit('Arch %s not tested' % arch)
> 
> It doens't look like you really need a full OS here. Rather than
> downloading the fairly large Fedora images, I'd suggest just using
> the kernel that exists on the host OS already in /boot, and then
> building a tiny initrd that contains just a static linked busybox.
> 
> I have this helper script that could be imported into QEMU for
> this purpose:
> 
>  https://gitlab.com/berrange/tiny-vm-tools/-/blob/master/make-tiny-image.py

Hi Daniel,

That’s a nifty script. I was trying to do something similar. Thank you for 
sharing!

—
Jag

> 
> And just skip the test if busybox doesn't exist, or if the vmlinux
> in /boot isn't accessible (Debian restricts it to root only IIRC)
> 
>> +
>> +urllib.request.urlretrieve(kernel_url, kernel_path)
>> +urllib.request.urlretrieve(initrd_url, initrd_path)
>> +
>> +proxy, remote = socket.socketpair(socket.AF_UNIX, socket.SOCK_STREAM)
>> +
>> +proxy_cmd.append('-device')
>> +proxy_cmd.append('x-pci-proxy-dev,id=lsi1,fd='+str(proxy.fileno()))
>> +
>> +remote_cmd = [ proc_path,                                                   
>>    \
>> +               '-machine', 'x-remote',                                      
>>    \
>> +               '-device', 'lsi53c895a,id=lsi1',                             
>>    \
>> +               '-object',                                                   
>>    \
>> +               
>> 'x-remote-object,id=robj1,devid=lsi1,fd='+str(remote.fileno()), \
>> +               '-display', 'none',                                          
>>    \
>> +               '-monitor', 'unix:/home/rem-sock,server,nowait',             
>>    \
>> +             ]
>> +
>> +pid = os.fork();
>> +
>> +if pid:
>> +    # In Proxy
>> +    print('Launching QEMU with Proxy object');
>> +    process = subprocess.Popen(proxy_cmd, pass_fds=[proxy.fileno()])
>> +else:
>> +    # In remote
>> +    print('Launching Remote process');
>> +    process = subprocess.Popen(remote_cmd, pass_fds=[remote.fileno(), 0, 1, 
>> 2])
> 
> Regards,
> Daniel
> -- 
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