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SubjectRe: [PATCH 2/5] iommu/amd: Implement DOMAIN_ATTR_GEOMETRY attribute
On Mon, Jan 30, 2012 at 06:27:30AM +0000, Sethi Varun-B16395 wrote:
> Can you please explain how would IOMMU remapping be used, based on the
> force_aperture flag.

If force_aperture is flase the dma-api code needs to check if remapping
is required at all. It performs the following checks:

* Does the physical address of the buffer not overlap with the
aperture?
* Fits the buffer into the device's dma address mask?

If both questions are answered with yes no remapping is required and
dma-api just returns the physical address. Otherwise it calls into the
dma-api to create a mapping.


Joerg

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AMD Operating System Research Center

Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
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