diff mbox series

[v3,1/3] dma: Fix encryption bit clearing for dma_to_phys

Message ID 20250227144150.1667735-2-suzuki.poulose@arm.com (mailing list archive)
State New, archived
Headers show
Series arm64: realm: Fix DMA address for devices | expand

Commit Message

Suzuki K Poulose Feb. 27, 2025, 2:41 p.m. UTC 
phys_to_dma() sets the encryption bit on the translated DMA address. But
dma_to_phys() clears the encryption bit after it has been translated back
to the physical address, which could fail if the device uses DMA ranges.

AMD SME doesn't use the DMA ranges and thus this is harmless. But as we
are about to add support for other architectures, let us fix this.

Reported-by: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Link: https://lkml.kernel.org/r/yq5amsen9stc.fsf@kernel.org
Cc: Will Deacon <will@kernel.org>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Steven Price <steven.price@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 include/linux/dma-direct.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Gavin Shan Feb. 28, 2025, 2:08 a.m. UTC | #1 
On 2/28/25 12:41 AM, Suzuki K Poulose wrote:
> phys_to_dma() sets the encryption bit on the translated DMA address. But
> dma_to_phys() clears the encryption bit after it has been translated back
> to the physical address, which could fail if the device uses DMA ranges.
> 
> AMD SME doesn't use the DMA ranges and thus this is harmless. But as we
> are about to add support for other architectures, let us fix this.
> 
> Reported-by: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
> Link: https://lkml.kernel.org/r/yq5amsen9stc.fsf@kernel.org
> Cc: Will Deacon <will@kernel.org>
> Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Robin Murphy <robin.murphy@arm.com>
> Cc: Steven Price <steven.price@arm.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Marek Szyprowski <m.szyprowski@samsung.com>
> Cc: Tom Lendacky <thomas.lendacky@amd.com>
> Reviewed-by: Robin Murphy <robin.murphy@arm.com>
> Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
>   include/linux/dma-direct.h | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
Reviewed-by: Gavin Shan <gshan@redhat.com>
diff mbox series

Patch

diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index d7e30d4f7503..d20ecc24cb0f 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -101,12 +101,13 @@  static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr)
 {
 	phys_addr_t paddr;
 
+	dma_addr = __sme_clr(dma_addr);
 	if (dev->dma_range_map)
 		paddr = translate_dma_to_phys(dev, dma_addr);
 	else
 		paddr = dma_addr;
 
-	return __sme_clr(paddr);
+	return paddr;
 }
 #endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */