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[159.2.73.22]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8d027f2035esm622941285a.19.2026.03.30.08.19.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Mar 2026 08:19:00 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1w7EOK-00000003SoK-1Tj8; Mon, 30 Mar 2026 12:19:00 -0300 Date: Mon, 30 Mar 2026 12:19:00 -0300 From: Jason Gunthorpe To: Mostafa Saleh 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, aneesh.kumar@kernel.org Subject: Re: [RFC PATCH v2 3/5] dma-mapping: Decrypt memory on remap Message-ID: <20260330151900.GC809900@ziepe.ca> References: <20260330145043.1586623-1-smostafa@google.com> <20260330145043.1586623-4-smostafa@google.com> 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: <20260330145043.1586623-4-smostafa@google.com> On Mon, Mar 30, 2026 at 02:50:41PM +0000, Mostafa Saleh wrote: > @@ -265,6 +266,9 @@ void *dma_direct_alloc(struct device *dev, size_t size, > set_uncached = false; > } > > + if (dma_set_decrypted(dev, page_address(page), size)) > + goto out_leak_pages; > + > if (remap) { > pgprot_t prot = dma_pgprot(dev, PAGE_KERNEL, attrs); > > if (force_dma_unencrypted(dev)) > prot = pgprot_decrypted(prot); It seems confusing, why do we unconditionally call something called dma_set_decrypted() and then conditionally call pgprot_decrypted()? So, I think the same remark, lets not sprinkle these tests all over the place and risk them becoming inconsistent. It should be much more direct, like: page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, allow_highmem, &flags); if (!dev_can_dma_from_encrypted(dev) && !(flags & FLAG_DECRYPTED)) { dma_set_decrypted(dev, page_address(page)); flags = FLAG_DECRYPTED; } if (flags & FLAG_DECRYPTED) prot = pgprot_decrypted(prot); And so on. The one place we should see a force_dma_unencrypted() is directly before setting the flag. Jason