Messages in this thread | | | Date | Tue, 6 Aug 2019 18:07:09 +0200 | From | Christoph Hellwig <> | Subject | Re: Regression due to d98849aff879 (dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING in common code) |
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On Tue, Aug 06, 2019 at 03:59:40PM +0000, Lendacky, Thomas wrote: > As long as two different cookie types (page pointer for encrypted DMA > and virtual address returned from page_address() for unencrypted DMA) > is ok. I'm just not familiar with how the cookie is used in any other > functions, if at all.
DMA_ATTR_NO_KERNEL_MAPPING is intended for memory never used in the kernel, either because it is just a buffer for device that are too cheap to enough dram, or because it is a buffer for userspace to device communication that the kernel just mediates.
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