kernel.git/kernel/dma/direct.c, branch linux-5.17.y

dma-direct: don't over-decrypt memory

2022-06-09T08:25:58Z

[ Upstream commit 4a37f3dd9a83186cb88d44808ab35b78375082c9 ] The original x86 sev_alloc() only called set_memory_decrypted() on memory returned by alloc_pages_node(), so the page order calculation fell out of that logic. However, the common dma-direct code has several potential allocators, not all of which are guaranteed to round up the underlying allocation to a power-of-two size, so carrying over that calculation for the encryption/decryption size was a mistake. Fix it by rounding to a *number* of pages, rather than an order. Until recently there was an even worse interaction with DMA_DIRECT_REMAP where we could have ended up decrypting part of the next adjacent vmalloc area, only averted by no architecture actually supporting both configs at once. Don't ask how I found that one out... Fixes: c10f07aa27da ("dma/direct: Handle force decryption for DMA coherent buffers in common code") Signed-off-by: Robin Murphy Signed-off-by: Christoph Hellwig Acked-by: David Rientjes Signed-off-by: Sasha Levin

dma-direct: don't fail on highmem CMA pages in dma_direct_alloc_pages

2022-06-09T08:25:50Z

[ Upstream commit 92826e967535db2eb117db227b1191aaf98e4bb3 ] When dma_direct_alloc_pages encounters a highmem page it just gives up currently. But what we really should do is to try memory using the page allocator instead - without this platforms with a global highmem CMA pool will fail all dma_alloc_pages allocations. Fixes: efa70f2fdc84 ("dma-mapping: add a new dma_alloc_pages API") Reported-by: Mark O'Neill Signed-off-by: Christoph Hellwig Signed-off-by: Sasha Levin

dma-direct: add a dma_direct_use_pool helper

2021-12-08T15:46:35Z

Add a helper to check if a potentially blocking operation should dip into the atomic pools. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

dma-direct: factor the swiotlb code out of __dma_direct_alloc_pages

2021-12-07T11:50:10Z

Add a new helper to deal with the swiotlb case. This keeps the code nicely boundled and removes the not required call to dma_direct_optimal_gfp_mask for the swiotlb case. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

dma-direct: drop two CONFIG_DMA_RESTRICTED_POOL conditionals

2021-12-07T11:50:10Z

swiotlb_alloc and swiotlb_free are properly stubbed out if CONFIG_DMA_RESTRICTED_POOL is not set, so skip the extra checks. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

dma-direct: warn if there is no pool for force unencrypted allocations

2021-12-07T11:50:10Z

Instead of blindly running into a blocking operation for a non-blocking gfp, return NULL and spew an error. Note that Kconfig prevents this for all currently relevant platforms, and this is just a debug check. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

dma-direct: fail allocations that can't be made coherent

2021-12-07T11:50:06Z

If the architecture can't remap or set an address uncached there is no way to fullfill a request for a coherent allocation. Return NULL in that case. Note that this case currently does not happen, so this is a theoretical fixup and/or a preparation for eventually supporting platforms that can't support coherent allocations with the generic code. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

dma-direct: refactor the !coherent checks in dma_direct_alloc

2021-12-07T11:49:57Z

Add a big central !dev_is_dma_coherent(dev) block to deal with as much as of the uncached allocation schemes and document the schemes a bit better. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

dma-direct: factor out a helper for DMA_ATTR_NO_KERNEL_MAPPING allocations

2021-12-07T11:49:50Z

Split the code for DMA_ATTR_NO_KERNEL_MAPPING allocations into a separate helper to make dma_direct_alloc a little more readable. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy Acked-by: David Rientjes

dma-direct: clean up the remapping checks in dma_direct_alloc

2021-12-07T11:48:09Z

Add two local variables to track if we want to remap the returned address using vmap or call dma_set_uncached and use that to simplify the code flow. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy