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From: Mostafa Saleh <smostafa@google.com>
To: iommu@lists.linux.dev, linux-kernel@vger.kernel.org
Cc: robin.murphy@arm.com, m.szyprowski@samsung.com, will@kernel.org,
	 maz@kernel.org, suzuki.poulose@arm.com, catalin.marinas@arm.com,
	 jiri@resnulli.us, jgg@ziepe.ca, aneesh.kumar@kernel.org,
	 Mostafa Saleh <smostafa@google.com>
Subject: [RFC PATCH v2 2/5] dma-mapping: Use the correct phys_to_dma() for DMA_RESTRICTED_POOL
Date: Mon, 30 Mar 2026 14:50:40 +0000	[thread overview]
Message-ID: <20260330145043.1586623-3-smostafa@google.com> (raw)
In-Reply-To: <20260330145043.1586623-1-smostafa@google.com>

As restricted dma pools are always decrypted, in swiotlb.c it uses
phys_to_dma_unencrypted() for address conversion.

However, in DMA-direct, calls to phys_to_dma_direct() with
force_dma_unencrypted() returning false, will fallback to
phys_to_dma() which is inconsistent for memory allocated from
restricted dma pools.

Fixes: f4111e39a52a ("swiotlb: Add restricted DMA alloc/free support")
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
 kernel/dma/direct.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 27d804f0473f..1a402bb956d9 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -26,7 +26,7 @@ u64 zone_dma_limit __ro_after_init = DMA_BIT_MASK(24);
 static inline dma_addr_t phys_to_dma_direct(struct device *dev,
 		phys_addr_t phys)
 {
-	if (force_dma_unencrypted(dev))
+	if (force_dma_unencrypted(dev) || is_swiotlb_for_alloc(dev))
 		return phys_to_dma_unencrypted(dev, phys);
 	return phys_to_dma(dev, phys);
 }
-- 
2.53.0.1185.g05d4b7b318-goog


  parent reply	other threads:[~2026-03-30 14:51 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-30 14:50 [RFC PATCH v2 0/5] dma-mapping: Fixes for memory encryption Mostafa Saleh
2026-03-30 14:50 ` [RFC PATCH v2 1/5] dma-mapping: Avoid double decrypting with DMA_RESTRICTED_POOL Mostafa Saleh
2026-03-30 15:06   ` Jason Gunthorpe
2026-03-30 20:43     ` Mostafa Saleh
2026-03-31 11:34       ` Suzuki K Poulose
2026-03-31 12:50         ` Mostafa Saleh
2026-03-30 14:50 ` Mostafa Saleh [this message]
2026-03-30 15:09   ` [RFC PATCH v2 2/5] dma-mapping: Use the correct phys_to_dma() for DMA_RESTRICTED_POOL Jason Gunthorpe
2026-03-30 20:47     ` Mostafa Saleh
2026-03-30 22:28       ` Jason Gunthorpe
2026-03-30 14:50 ` [RFC PATCH v2 3/5] dma-mapping: Decrypt memory on remap Mostafa Saleh
2026-03-30 15:19   ` Jason Gunthorpe
2026-03-30 20:49     ` Mostafa Saleh
2026-03-30 22:30       ` Jason Gunthorpe
2026-03-30 14:50 ` [RFC PATCH v2 4/5] dma-mapping: Refactor memory encryption usage Mostafa Saleh
2026-03-30 15:27   ` Jason Gunthorpe
2026-03-30 14:50 ` [RFC PATCH v2 5/5] dma-mapping: Add doc for memory encryption Mostafa Saleh

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