Re: [Qemu-devel] Semantics of DeviceState::realized and BlockDriverState

[Kevin Wolf <kwolf@redhat.com>]

Am 12.06.2012 00:05, schrieb Anthony Liguori:
> To me, realized represents Vcc.  When realized=true, the guest has power and is 
> active.  When realized=false, the guest has lost power.  The realize() event is 
> the rising edge of Vcc, unrealized() is the falling edge.
> 
> realize() should be used to take any actions that require all parameters to be 
> set that need to happen before the guest has power.  This later clause is 
> extremely important.  unrealize() should be used to unset anything setup in 
> realize().

The one thing I'm really unsure about is whether you're combining two
different things into one concept: This Vcc concept and Andreas' OOP
concept (which is btw the same as I understood realize before we
discussed yesterday on IRC - I guess you must have explained it as such
at some point).

Is it really always the power-on event that causes the final check of
properties, setup of device state and makes some properties read-only?
Or is that just a coincidence and happens to be true only with some devices?

> The destructor being invoked does not imply that unrealize() has happened.

Which makes some sense in your Vcc model, but doesn't at all in the OOP
concept model.

Kevin