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

From: Alexey Kardashevskiy
Subject: Re: [Qemu-trivial] [RFC PATCH] spapr-pci: Enable huge BARs
Date: Tue, 18 Nov 2014 13:37:40 +1100
User-agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0

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


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