Re: Page alignment & memory regions expectations

[David Hildenbrand <david@redhat.com>]

On 25.08.22 13:47, Peter Maydell wrote:
> On Thu, 25 Aug 2022 at 08:27, David Hildenbrand <david@redhat.com> wrote:
>> On 24.08.22 21:55, Peter Maydell wrote:
>>> Lumps of memory can be any size you like and anywhere in
>>> memory you like. Sometimes we are modelling real hardware
>>> that has done something like that. Sometimes it's just
>>> a convenient way to model a device. Generic code in
>>> QEMU does need to cope with this...
>>
>> But we are talking about system RAM here. And judging by the fact that
>> this is the first time dump.c blows up like this, this doesn't seem to
>> very common, no?
> 
> What's your definition of "system RAM", though? The biggest

I'd say any RAM memory region that lives in address_space_memory /
get_system_memory(). That's what softmmu/memory_mapping.c cares about
and where we bail out here.


> bit of RAM in the system? Anything over X bytes? Whatever
> the machine set up as MachineState::ram ? As currently
> written, dump.c is operating on every RAM MemoryRegion
> in the system, which includes a lot of things which aren't
> "system RAM" (for instance, it includes framebuffers and
> ROMs).

Anything in address_space_memory / get_system_memory(), correct. And
this seems to be the first time that we fail here, so it's either a case
we should be handling in dump code (as you indicate) or some case we
shouldn't have to worry about (as I questioned).

> 
> -- PMM
> 


-- 
Thanks,

David / dhildenb