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

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Message-ID: <20251221160920.297689-5-aneesh.kumar@kernel.org>
Date: Sun, 21 Dec 2025 21:39:20 +0530
From: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@...nel.org>
To: linux-kernel@...r.kernel.org,
	iommu@...ts.linux.dev,
	linux-coco@...ts.linux.dev
Cc: Catalin Marinas <catalin.marinas@....com>,
	will@...nel.org,
	maz@...nel.org,
	tglx@...utronix.de,
	robin.murphy@....com,
	suzuki.poulose@....com,
	akpm@...ux-foundation.org,
	jgg@...pe.ca,
	steven.price@....com,
	"Aneesh Kumar K.V (Arm)" <aneesh.kumar@...nel.org>
Subject: [PATCH v2 4/4] dma: direct: set decrypted flag for remapped dma allocations

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@...nel.org>
---
 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