• Benjamin Herrenschmidt's avatar
    powerpc/powernv: Add iommu DMA bypass support for IODA2 · cd15b048
    Benjamin Herrenschmidt authored
    This patch adds the support for to create a direct iommu "bypass"
    window on IODA2 bridges (such as Power8) allowing to bypass iommu
    page translation completely for 64-bit DMA capable devices, thus
    significantly improving DMA performances.
    Additionally, this adds a hook to the struct iommu_table so that
    the IOMMU API / VFIO can disable the bypass when external ownership
    is requested, since in that case, the device will be used by an
    environment such as userspace or a KVM guest which must not be
    allowed to bypass translations.
    Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
pci.c 23 KB