Re: [Qemu-devel] [PATCH] monitor: Add port write command

[Anthony Liguori <aliguori@us.ibm.com>]

Paul Brook wrote:
>> What would be really cool about this change is that we could introduce a
>> new set of commands to manipulate device state.  We could save/restore
>> individual device state and that would allow us to dump device state via
>> the monitor and to manipulate individual fields of the device state.  I
>> think this could be pretty useful for debugging.
>>     
>
> I'd be reluctant to expose the savevm state to the user.
>
> For debugging qemu I don't see it providing any real benefit over firing up 
> GDB and poking directly at the device directly.
>
> For debugging the guest there is some argument for exposing the device state 
> (preferably via the gdb stub). However I think the savevm data tends to expose 
> too many internal implementation details,

That sounds like an issue with the devices.

The savevm state should not contain internal implementation details as 
that makes backwards compatibility hard to maintain.  I think for a 
large class of devices, the savevm state almost perfectly matches the 
device register state and having a nice interface to that seems like a 
useful thing.

-- 
Regards,

Anthony Liguori