linux-kernel - Re: [PATCH v2] dma-direct: set decrypted flag for remapped DMA allocations

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Message-ID: <20260105175323.GF125261@ziepe.ca>
Date: Mon, 5 Jan 2026 13:53:23 -0400
From: Jason Gunthorpe <jgg@...pe.ca>
To: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@...nel.org>
Cc: iommu@...ts.linux.dev, linux-kernel@...r.kernel.org,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Robin Murphy <robin.murphy@....com>,
	Arnd Bergmann <arnd@...nel.org>, Linus Walleij <linusw@...nel.org>,
	Matthew Wilcox <willy@...radead.org>,
	Suzuki K Poulose <suzuki.poulose@....com>
Subject: Re: [PATCH v2] dma-direct: set decrypted flag for remapped DMA
 allocations

On Fri, Jan 02, 2026 at 09:20:37PM +0530, Aneesh Kumar K.V (Arm) wrote:
> Devices that are DMA non-coherent and require a remap were skipping
> dma_set_decrypted(), leaving DMA buffers encrypted even when the device
> requires unencrypted access. Move the call after the if (remap) branch
> so that both the direct and remapped allocation paths correctly mark the
> allocation as decrypted (or fail cleanly) before use.

This is probably fine, but IMHO, we should be excluding the
combination of highmem and CC at the kconfig level :\

Jason