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[47.54.130.67]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8e7d5fe90afsm155521685a.3.2026.04.17.08.28.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 17 Apr 2026 08:28:28 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1wDl7M-0000000DQhO-16Cq; Fri, 17 Apr 2026 12:28:28 -0300 Date: Fri, 17 Apr 2026 12:28:28 -0300 From: Jason Gunthorpe To: "Aneesh Kumar K.V (Arm)" Cc: iommu@lists.linux.dev, linux-kernel@vger.kernel.org, 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, Mostafa Saleh Subject: Re: [RFC PATCH 2/7] dma-direct: use DMA_ATTR_CC_DECRYPTED in alloc/free paths Message-ID: <20260417152828.GJ2577880@ziepe.ca> References: <20260417085900.3062416-1-aneesh.kumar@kernel.org> <20260417085900.3062416-3-aneesh.kumar@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260417085900.3062416-3-aneesh.kumar@kernel.org> On Fri, Apr 17, 2026 at 02:28:55PM +0530, Aneesh Kumar K.V (Arm) wrote: > Propagate force_dma_unencrypted() into DMA_ATTR_CC_DECRYPTED in the > dma-direct allocation path and use the attribute to drive the related > decisions. > > This updates dma_direct_alloc(), dma_direct_free(), and > dma_direct_alloc_pages() to fold the forced unencrypted case into attrs. > > Signed-off-by: Aneesh Kumar K.V (Arm) > --- > kernel/dma/direct.c | 34 ++++++++++++++++++++++++++-------- > 1 file changed, 26 insertions(+), 8 deletions(-) > > diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c > index c2a43e4ef902..3932033f4d8c 100644 > --- a/kernel/dma/direct.c > +++ b/kernel/dma/direct.c > @@ -201,16 +201,21 @@ void *dma_direct_alloc(struct device *dev, size_t size, > dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) > { > bool remap = false, set_uncached = false; > - bool mark_mem_decrypt = true; > + bool mark_mem_decrypt = !!(attrs & DMA_ATTR_CC_DECRYPTED); > struct page *page; This is changing the API, I think it should not be hidden in a patch like this, also not sure it even makes sense.. DMA_ATTR_CC_DECRYPTED only says the address passed to mapping is decrypted. It is like DMA_ATTR_MMIO in this regard. Passing it to dma_alloc_attrs() is currently invalid, and I think it should remain invalid, or at least this new behavior introduced in its own patch deliberately. Meaning, if you call dma_direct_alloc() force_dma_decrypted decides what setting DMA_ATTR_CC_DECRYPTED takes and it is EOPNOTSUPP if the user passes it in. Jason