On Fri, May 29, 2015 at 06:44:58PM +1000, Alexey Kardashevskiy wrote:
> This adds create/remove window ioctls to create and remove DMA windows.
> sPAPR defines a Dynamic DMA windows capability which allows
> para-virtualized guests to create additional DMA windows on a PCI bus.
> The existing linux kernels use this new window to map the entire guest
> memory and switch to the direct DMA operations saving time on map/unmap
> requests which would normally happen in a big amounts.
>
> This adds 2 ioctl handlers - VFIO_IOMMU_SPAPR_TCE_CREATE and
> VFIO_IOMMU_SPAPR_TCE_REMOVE - to create and remove windows.
> Up to 2 windows are supported now by the hardware and by this driver.
>
> This changes VFIO_IOMMU_SPAPR_TCE_GET_INFO handler to return additional
> information such as a number of supported windows and maximum number
> levels of TCE tables.
>
> DDW is added as a capability, not as a SPAPR TCE IOMMU v2 unique feature
> as we still want to support v2 on platforms which cannot do DDW for
> the sake of TCE acceleration in KVM (coming soon).
>
> Signed-off-by: Alexey Kardashevskiy <[email protected]>
> [aw: for the vfio related changes]
> Acked-by: Alex Williamson <[email protected]>
Reviewed-by: David Gibson <[email protected]>
--
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