Commit 4fe87e81 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

dma-mapping: move pgprot_decrypted out of dma_pgprot 



pgprot_decrypted is used by AMD SME systems to allow access to memory
that was set to not encrypted using set_memory_decrypted.  That only
happens for dma-direct memory as the IOMMU solves the addressing
challenges for the encryption bit using its own remapping.

Move the pgprot_decrypted call out of dma_pgprot which is also used
by the IOMMU mappings and into dma-direct so that it is only used with
memory that was set decrypted.

Fixes: f5ff79fd ("dma-mapping: remove CONFIG_DMA_REMAP")
Reported-by: default avatarAlex Xu (Hello71) <alex_y_xu@yahoo.ca>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Tested-by: default avatarAlex Xu (Hello71) <alex_y_xu@yahoo.ca>
parent 05b0ebd0

kernel/dma/direct.c

+8 −2
Original line number Diff line number Diff line
@@ -277,12 +277,16 @@ void *dma_direct_alloc(struct device *dev, size_t size, 
	}



	if (remap) {

		pgprot_t prot = dma_pgprot(dev, PAGE_KERNEL, attrs);



		if (force_dma_unencrypted(dev))

			prot = pgprot_decrypted(prot);



		/* remove any dirty cache lines on the kernel alias */

		arch_dma_prep_coherent(page, size);



		/* create a coherent mapping */

		ret = dma_common_contiguous_remap(page, size,

				dma_pgprot(dev, PAGE_KERNEL, attrs),

		ret = dma_common_contiguous_remap(page, size, prot,

				__builtin_return_address(0));

		if (!ret)

			goto out_free_pages;
@@ -535,6 +539,8 @@ int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma, 
	int ret = -ENXIO;



	vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);

	if (force_dma_unencrypted(dev))

		vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);



	if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))

		return ret;

kernel/dma/mapping.c

+0 −2
Original line number Diff line number Diff line
@@ -407,8 +407,6 @@ EXPORT_SYMBOL(dma_get_sgtable_attrs); 
 */

pgprot_t dma_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs)

{

	if (force_dma_unencrypted(dev))

		prot = pgprot_decrypted(prot);

	if (dev_is_dma_coherent(dev))

		return prot;

#ifdef CONFIG_ARCH_HAS_DMA_WRITE_COMBINE