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

[Suzuki K Poulose]

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

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 */
 
-- 
2.43.0