Linux kernel has a default 32-bit segmentation boundary for
any device that doesn't explicitly configure it. When nvgpu
tries to allocate a larger memory > 4GB, iommu_dma_map_sg()
function in the kernel will take this boundary into account
and add an internal padding to the allocated IOVA space:
|<---IOVA space 1--->|<---padding--->|<---IOVA space 2--->|
When DMA reads/writes the memory using this discountinued
IOVA space, it may end up with accessing the padding part,
instead of the IOVA space 2.
So this patch adds dma_set_seg_boundary() to nvgpu driver,
by maximizing the segmentation boundary up to DMA_BIT_MASK
to ensure a continued IOVA space.
Bug 200558567
Change-Id: I979d56681dddca56f1b02fce83dc81147a6b0d82
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2304150
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Pritesh Raithatha <praithatha@nvidia.com>
Reviewed-by: Puneet Saxena <puneets@nvidia.com>
Reviewed-by: Chris Dragan <kdragan@nvidia.com>
Reviewed-by: Sachin Nikam <snikam@nvidia.com>
Reviewed-by: Alex Waterman <alexw@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
GVS: Gerrit_Virtual_Submit
5e854efa65