Re: [PATCH kernel v11 28/34] vfio: powerpc/spapr: powerpc/powernv/ioda: Define and implement DMA windows API

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

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On Fri, May 29, 2015 at 06:44:52PM +1000, Alexey Kardashevskiy wrote:
> This extends iommu_table_group_ops by a set of callbacks to support
> dynamic DMA windows management.
> 
> create_table() creates a TCE table with specific parameters.
> it receives iommu_table_group to know nodeid in order to allocate
> TCE table memory closer to the PHB. The exact format of allocated
> multi-level table might be also specific to the PHB model (not
> the case now though).
> This callback calculated the DMA window offset on a PCI bus from @num
> and stores it in a just created table.
> 
> set_window() sets the window at specified TVT index + @num on PHB.
> 
> unset_window() unsets the window from specified TVT.
> 
> This adds a free() callback to iommu_table_ops to free the memory
> (potentially a tree of tables) allocated for the TCE table.
> 
> create_table() and free() are supposed to be called once per
> VFIO container and set_window()/unset_window() are supposed to be
> called for every group in a container.
> 
> This adds IOMMU capabilities to iommu_table_group such as default
> 32bit window parameters and others. This makes use of new values in
> vfio_iommu_spapr_tce. IODA1/P5IOC2 do not support DDW so they do not
> advertise pagemasks to the userspace.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> Acked-by: Alex Williamson <alex.williamson@redhat.com>

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

-- 
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