[dpdk-dev] [PATCH v4 1/1] vfio: modify spapr iommu support to use static window sizing

[Thomas Monjalon]

Anatoly, please could you review this patch?

15/10/2020 19:23, David Christensen:
> The SPAPR IOMMU requires that a DMA window size be defined before memory
> can be mapped for DMA. Current code dynamically modifies the DMA window
> size in response to every new memory allocation which is potentially
> dangerous because all existing mappings need to be unmapped/remapped in
> order to resize the DMA window, leaving hardware holding IOVA addresses
> that are temporarily unmapped.  The new SPAPR code statically assigns
> the DMA window size on first use, using the largest physical memory
> memory address when IOVA=PA and the highest existing memseg virtual
> address when IOVA=VA.
> 
> Signed-off-by: David Christensen <drc at linux.vnet.ibm.com>