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Date: Wed, 26 Oct 2011 09:52:20 -0400
From: John Baboval <john.baboval@virtualcomputer.com>
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Subject: [Qemu-devel] New Memory API Question
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To: qemu-devel@nongnu.org, avi@redhat.com

Sorry for coming late to the party on this... I only read qemu-devel 
through a filter so I missed all the discussions on the new memory API. 
I have a question as to how it works and how it's supposed to work in 
certain scenarios.

It's a question of flow. I'm following the code path through the 
creation of a new memory subregion. If I'm reading this properly, it 
would seem that a MemoryRegion - for example the ones used by VGA - go 
through the following flow:

memory_region_init_ram()   - (mr->destructor is set to 
memory_region_destructor_ram)
memory_region_add_subregion(system_memory, ...) ->
    memory_region_update_topology() ->
       address_space_update_topology()
          address_space_update_topology_part()
             as_memory_range_add()   - through the ops vector
                memory_region_prepare_ram_addr()


At this point it seems that the destructor is overwritten with the 
memory_region_destructor_iomem(), and it loses track of the proper way 
to ever free the memory region. Is this correct, or am I missing something?

Or does it not matter because nobody ever calls memory_region_destroy 
for system memory regions?

Thanks,
-John