Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state

[Jan Kiszka]

On 2011-01-18 18:31, Anthony Liguori wrote:
>>> It's automatically created as part of the CPUs or as part of the
>>> chipset.  How to enable/disable kvm assistance is a property of the CPU
>>> and/or chipset.
>>>      
>> If we exclude creation via command line / config files, we could also
>> pass the kvm_state directly from the machine or chipset setup code and
>> save us at least the kvm system buses.
>>    
> 
> Which is fine in the short term.

Unless we want to abuse the pointer property for this, and there was
some resistance, we would have to change the sysbus init function
signature. I don't want to propose this for a short-term workaround, we
need a clearer vision and roadmap to avoid multiple invasive changes to
the device model.

>  This is exactly why we don't want the 
> device model to be an ABI.   It gives us the ability to make changes as 
> they make sense instead of trying to be perfect from the start (which we 
> never will be).

The device model will always consist of a stable part, the guest and
management visible topology. That beast needs to be modeled as well,
likely via some new bus objects. If that's the way to go, starting now
is probably the right time as we have an urgent use case, right?

Jan

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