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

From: Alexander Graf
Subject: Re: [Qemu-trivial] [RFC PATCH] spapr-pci: Enable huge BARs
Date: Mon, 17 Nov 2014 13:43:24 +0100

> 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.


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