[PATCH v2 4/4] dma: direct: set decrypted flag for remapped dma allocations

From: Aneesh Kumar K.V (Arm)

Date: Sun Dec 21 2025 - 11:10:18 EST


Devices that are DMA non-coherent and need a remap were skipping
dma_set_decrypted(), leaving buffers encrypted even when the device
requires unencrypted access. Move the call after the remap
branch so both paths mark the allocation decrypted (or fail cleanly)
before use.

Fixes: f3c962226dbe ("dma-direct: clean up the remapping checks in dma_direct_alloc")
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@xxxxxxxxxx>
---
kernel/dma/direct.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 3448d877c7c6..a62dc25524cc 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -271,9 +271,6 @@ 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);

@@ -284,10 +281,11 @@ void *dma_direct_alloc(struct device *dev, size_t size,
goto out_free_pages;
} else {
ret = page_address(page);
- if (dma_set_decrypted(dev, ret, size))
- goto out_leak_pages;
}

+ if (dma_set_decrypted(dev, ret, size))
+ goto out_leak_pages;
+
memset(ret, 0, size);

if (set_uncached) {
--
2.43.0