On Fri, 07 Nov 2025 10:11:05 -0600, Gaurav Batra wrote:

Leverage ARCH_HAS_DMA_MAP_DIRECT config option for coherent allocations as
well. This will bypass DMA ops for memory allocations that have been
pre-mapped.

Always set device bus_dma_limit when memory is pre-mapped. In some
architectures, like PowerPC, pmemory can be converted to regular memory via
daxctl command. This will gate the coherent allocations to pre-mapped RAM
only, by dma_coherent_ok().

[...]

Applied to powerpc/next.

[1/1] powerpc/iommu: bypass DMA APIs for coherent allocations for pre-mapped memory
      https://git.kernel.org/powerpc/c/1471c517cf7dae1a6342fb821d8ed501af956dd0

cheers