Re: [qemu-s390x] [PATCH/RFC] s390x: split memory into 4TB chunks

[David Hildenbrand]

>>>> This will most certainly break migration, no?
>>>
>>> Probably yes. Thats why the patch has RFC. I was looking for ideas.
>>
>> As other architectures might also run into this problem, wonder if
>>
>> a) bumping up KVM_MEM_MAX_NR_PAGES makes sense.
> 
> The original limitation comes from the fact that this define is used to limit
> the number of bits in the dirty bitmap as some architectures do not provide
> bitops beyond 2^32.

Then my question would be if we can bump it up for all architectures
that support it.

> 
>> b) as I said, transparently handle it in kvm slot handling code.
> 
> adding Paolo to check what he thinks.
>>
>>>>
>>>> 1. I remember the name being used for migration, I might be wrong.
>>>> 2. Migration of guests > 4TB is certainly broken ;)
>>>>
>>>> I wonder if this should rather be handled in the kvm_slot code.
>>>> (silently create an manage two slots)
>>>
>>
>>
> 


-- 

Thanks,

David / dhildenb