Re: [PATCH v2 1/3] dma: Fix encryption bit clearing for dma_to_phys
From: Tom Lendacky <thomas.lendacky@amd.com>
Date: 2025-02-25 15:26:23
Also in:
lkml
On 2/19/25 16:07, 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. Hopefully, AMD SME doesn't use it. Anyways, let us fix it, before cleanup the infrastructure for supporting other architectures.
I'm not aware of anything using DMA ranges on SME capable hardware. And as you stated, this would have failed if there was. Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
quoted hunk ↗ jump to hunk
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 <redacted> 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: 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(-)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 */