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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

    --
    AMD Operating System Research Center

    Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
    General Managers: Alberto Bozzo
    Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632



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