Re: [RFC v2 01/20] Hierarchical memory region API

Jan Kiszka
2011-06-28T12:46:52Z

On 2011-06-28 14:09, Avi Kivity wrote:
> On 06/28/2011 03:07 PM, Jan Kiszka wrote:
>>>
>>> The point is that different buses have different widths.
>>> target_phys_addr_t matches just one bus in the system. It needs to be
>>> the maximum size of all buses present to be useful.
>>
>> Then we need a type for that. Or we need to demand that
>> target_phys_addr_t is defined large enough to support all buses that the
>> particular arch wants to address. Hardcoding 64 bit or anything is not
>> appropriate for a generic subsystem.
>
> Okay, let's make t_p_a_t max(bus size in system). Do we have 32-bit
> targets that don't support pci (I guess, pc-isa with cpu < ppro?).

At least lm32 and microblaze appear to fall into that category.

> Do we want to support a 32-bit variant of pci? It certainly existed at
> some point.

As long as making everything 64 bit in the implementation of the device
models is not guest visible, I don't think that should be a problem.

Jan

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