From 4fe87e818ea492ade079cc01a31d088e445f8539 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Thu, 31 Mar 2022 08:01:21 +0200
Subject: [PATCH] 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: f5ff79fddf0e ("dma-mapping: remove CONFIG_DMA_REMAP")
Reported-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca>
---
kernel/dma/direct.c | 10 ++++++++--
kernel/dma/mapping.c | 2 --
2 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 35a1d29d6a2e9..9743c6ccce1a9 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -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;
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 559461a826bab..db7244291b745 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -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
--
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