Re: [Qemu-devel] [PATCH v5 3/6] vl: allow customizing the class of /machine

[Andreas Färber]

Am 20.02.2014 14:58, schrieb Paolo Bonzini:
> Il 20/02/2014 14:50, Alexey Kardashevskiy ha scritto:
>> From: Paolo Bonzini <address@hidden>
>>
>> This is a first step towards QOMifying /machine.
>>
>> Signed-off-by: Paolo Bonzini <address@hidden>
> 
> The patch was originally mine, so I could get it in if Andreas wants me
> to handle patches 2-3.  But for anyone else it would be missing your
> S-o-b line.

With this patch I have been plagued by doubts of whether we can run into
a race of creating /machine through qdev_get_machine() via command line
option handling or whatever other code paths. I'm at a conference and
did not find time yet to test this out - if you two could investigate
and clarify, that would be helpful in moving forward.

Also I thought that someone else had looked into replacing the whole of
machine_init and QEMUMachine with QOM infrastructure? Anyway it was an
idea that I once had, Anthony didn't like at first and then someone else
(Luiz?) convinced Anthony to do it after all but then somehow it got
stuck with no patches posted... The discussed approach was instead of
creating a type in machine init depending on some
QEMUMachine::class_name, always create the type. But either approach
conflicts with creating /machine as Container type, as mentioned above.
If we go with such an interim solution then at least qdev.c needs to
grow an assert.

Regards,
Andreas

> 
> Paolo
> 
>> ---
>>  include/hw/boards.h | 1 +
>>  vl.c                | 5 +++++
>>  2 files changed, 6 insertions(+)
>>
>> diff --git a/include/hw/boards.h b/include/hw/boards.h
>> index c2096e6..8640272 100644
>> --- a/include/hw/boards.h
>> +++ b/include/hw/boards.h
>> @@ -29,6 +29,7 @@ struct QEMUMachine {
>>      const char *name;
>>      const char *alias;
>>      const char *desc;
>> +    const char *class_name;
>>      QEMUMachineInitFunc *init;
>>      QEMUMachineResetFunc *reset;
>>      QEMUMachineHotAddCPUFunc *hot_add_cpu;
>> diff --git a/vl.c b/vl.c
>> index 01ab7e4..b300721 100644
>> --- a/vl.c
>> +++ b/vl.c
>> @@ -4034,6 +4034,11 @@ int main(int argc, char **argv, char **envp)
>>          qtest_init(qtest_chrdev, qtest_log);
>>      }
>>
>> +    if (machine->class_name) {
>> +        Object *m = object_new(machine->class_name);
>> +        object_property_add_child(object_get_root(), "machine", m,
>> NULL);
>> +    }
>> +
>>      machine_opts = qemu_get_machine_opts();
>>      kernel_filename = qemu_opt_get(machine_opts, "kernel");
>>      initrd_filename = qemu_opt_get(machine_opts, "initrd");
>>
> 
> 


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