Messages in this thread | | | Date | Tue, 2 Nov 2021 07:43:56 +0100 | From | Christoph Hellwig <> | Subject | Re: [PATCH] dma-direct: fix DMA_ATTR_NO_KERNEL_MAPPING |
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On Tue, Nov 02, 2021 at 11:21:16AM +0800, Walter Wu wrote: > Our platform is arch64. We need a dynamic allocated buffer from CMA is > not to read by CPU peculative execution, so we need to remove its > kernel mapping.
If your CPU speculates into unused kernel direct mappings your have a worse problem than this, because all the dma coherent allocations for non-coherent devices still have a cachable direct mapping. Will mentioned he wanted to look into getting rid of that mapping now that the core dma code has the infrastucture for that, so adding him here.
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