Re: [Qemu-devel] [PATCH] memory: info mtree check mr range overflow

[Mark Cave-Ayland]

On 15/03/17 04:23, Michael S. Tsirkin wrote:

>>>> Could you help elaborate in what case will we really need that 128 bit
>>>> address?
>>>
>>> This is how memory API works. It uses 128 bit addresses (in reality
>>> it typically only needs 64 bit addresses but 128 means it can do
>>> math without worrying about it too much).
>>
>> Yes. To be more specific, could I ask why do we need 128 bits here
>> when doing "info mtree"?
> 
> Because when you add two 64 bit addresses you sometimes get a 67
> bit one. info mtree shows some fictitious data: base/end addresses
> that region would have had if it was fully visible in a flatview.
> 67 bit addresses are never visible there, that is true,
> but that is not the only kind of address that is not visible
> in flatview yet shown by info mtree.

Note that I'm going to send a PR for the OpenBIOS fix hopefully later
today which means the original test case shouldn't occur anymore.

However I will manually test any patches that are submitted to verify
that they work correctly for this particular case.


ATB,

Mark.