Re: [Qemu-ppc] [PATCH qemu v7 06/14] spapr_iommu: Introduce "enabled" state for TCE table

[Paolo Bonzini]

On 26/05/2015 14:33, Alexey Kardashevskiy wrote:
> 
>>>> If it's not true now that they can be unparented at any time like
>>>> alias regions, we should probably try to make it true.
>>>
>>> Unfortunately it's not so easy...
> 
> 
> Uff. Tricky :)
> 
> memory_region_del_subregion() is not unparenting but just a wrapped
> object_unref(), right?

Right.  The problematic thing to do is explicit object_unparent followed
by one of the following:

1) memory_region_init for the same memory region that has been unparented

2) g_free of some dynamically-allocated data structure that contained
the memory region.

> But since iommu MR are resolved dynamically, the
> whole conversation we are having here now has nothing to do with my&Mike
> concern what we can and cannot do with DMA windows here. Is this correct?

I don't understand what you're asking here, sorry.

Paolo