[Qemu-devel] when the device property is called?

[Qemu-devel] when the device property is called?

[Wang Dong]

Hi,

I am newbie to qemu. Recently, I am reading the code and found one question.

I can see some property function is added to the object. But I wonder 
when these

property functions are called or triggered. When I try to trace them, 
only the initialization

is found. I found some unclear lines in the doc, I can not figure out 
the details.

*"Device properties in QOM are bound to devices and are implemented by 
closures provided by the device.
***

*A Visitor is passed to the closure which effectively allows properties 
to be set/get through native C types.***

*Mapping to any other type of representation (string or otherwise) is 
done by a Visitor with no knowledge of the device or property.***

  "

I also found this property function has something to do with the 
*Visitor*, and I trace the function *x86_cpu_get_crash_info_qom* along with

Visitor. And I found that these crash information is finally read out to 
log file along with this visitor. *But **still I have no idea when this **
**x86_cpu_get_crash_info_qom is triggered.
*

But as I found that the cpu class is initialized with an another 
function *cc->get_crash_info = x86_cpu_get_crash_info*

And with this function, the crash information will also be put out to 
log file. And this function will return a crash information struct to 
*qemu_system_**guest**_panicked*, which will then print the crash info 
to log file too.

*I wonder what is the difference between them? And when the property 
function is called?
*

*
*

*Any clue will be very appreciated. Thanks in advance.
*

Thanks in advance.



-- 
Best regards.

Wang Dong