Re: [Qemu-trivial] [RFC PATCH] spapr-pci: Enable huge BARs

[Alexey Kardashevskiy]

On 11/17/2014 11:43 PM, Alexander Graf wrote:
> 
> 
> 
>> Am 17.11.2014 um 04:54 schrieb Alexey Kardashevskiy <address@hidden>:
>>
>> At the moment sPAPR only supports 512MB window for MMIO BARs. However
>> modern devices might want bigger 64bit BARs.
>>
>> This adds another 64bit MMIO window per PHB and advertises it via
>> the PHB's "ranges" property in the device tree. The new window is 1TB long
>> and starts from 1TB offset on a PCI address space.
>>
>> Older (<3.12) kernels expect BARs to have the same offset on both bus
>> and memory address spaces. Since we are getting now another MMIO region,
>> we either have to add (0xA000.0000 - 0x8000.0000) offset to
>> its bus offset OR simply put MMIO range at the same offset as on the bus.
>> This puts 32bit MMIO space at 0x8000.0000 offset in RAM and IO space
>> at 0xA000.0000 (used to be vice versa).
>>
>> While we are here, let's increase PHB address spacing from 64GB to 16TB
>> in order not to touch it again any time soon.
>>
>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
> 
> I'll have to digthrough the compatibility matrix details myself still, but 
> please make sure that you don't change address space layouts for pseries-2.2.

Right. Still restoring after Europe :)
Ben suggested better idea about windows so never mind, I'll post another
version.



-- 
Alexey