Re: [Qemu-devel] [PATCH qemu v7 07/14] spapr_iommu: Add root memory region

[David Gibson <david@gibson.dropbear.id.au>]

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On Sat, Apr 25, 2015 at 10:24:37PM +1000, Alexey Kardashevskiy wrote:
> We are going to have multiple DMA windows at different offsets on
> a PCI bus. For the sake of migration, we will have as many TCE table
> objects pre-created as many windows supported.
> So we need a way to map windows dynamically onto a PCI bus
> when migration of a table is completed but at this stage a TCE table
> object does not have access to a PHB to ask it to map a DMA window
> backed by just migrated TCE table.
> 
> This adds a "root" memory region (UINT64_MAX long) to the TCE object.
> This new region is mapped on a PCI bus with enabled overlapping as
> there will be one root MR per TCE table, each of them mapped at 0.
> The actual IOMMU memory region is a subregion of the root region and
> a TCE table enables/disables this subregion and maps it at
> the specific offset inside the root MR which is 1:1 mapping of
> a PCI address space.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

-- 
David Gibson			| I'll have my music baroque, and my code
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