From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8A9F8E98E10 for ; Mon, 23 Feb 2026 09:51:45 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9EB4210E2D0; Mon, 23 Feb 2026 09:51:44 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=resnulli-us.20230601.gappssmtp.com header.i=@resnulli-us.20230601.gappssmtp.com header.b="02w6FyZ+"; dkim-atps=neutral Received: from mail-wm1-f41.google.com (mail-wm1-f41.google.com [209.85.128.41]) by gabe.freedesktop.org (Postfix) with ESMTPS id CED6010E033 for ; Mon, 23 Feb 2026 09:51:40 +0000 (UTC) Received: by mail-wm1-f41.google.com with SMTP id 5b1f17b1804b1-4834826e5a0so50787355e9.2 for ; Mon, 23 Feb 2026 01:51:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=resnulli-us.20230601.gappssmtp.com; s=20230601; t=1771840299; x=1772445099; darn=lists.freedesktop.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=jZyzh76/vi/WA0Mw21DKfbc+O5VrV1Ds2EV/BZWk6NE=; b=02w6FyZ+DBckTjEwplxe3NNEdXzvJcbx5a47K0KKNUznF7vlZogDJebd1Ala1AhF5V zxUq3/6gqR7duH1h+T2SR9GFsRC9qMcz0h9FyFYWFhK006x1vpahnp+Vbg/k5qaM3tXX Pukp7q3/gDoqQwf+TAtZtMVwOQ8zWdjoubI1IlZvfBY45PV5RGxlpNraslb1SebGrL0B sTYE3bXy+qj4+vJq9MtxA+MNtVuuPPSXbMrSvBIpGnofSWA47VmLy+D/F9DP0atnP0yX UA66mAegRR1ZY0wDp57Qf+jNXrx6mYC7WP4o0BlI+DpADoARL6DPvQCRNdhARBKk07F9 gcyw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771840299; x=1772445099; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=jZyzh76/vi/WA0Mw21DKfbc+O5VrV1Ds2EV/BZWk6NE=; b=EOAzwAh8LwufAFLC5YcVL/nDZg45oQo5iJKtM8BwV0huHqW8Q8OLzlPhiC42erl3b2 poNlSAwyTLEVc0oSFHbQ3y9ZOGMycleD0f2Qxv3QfszlMxexPNGuyDpk7PAyyC6enLEL qK3BNzp4qwCLd3QBZbh0bg5Dt3pIFqXitl3BmslVSAwNUH0hlEuEFI53ojM4N8hPiUVA o/QJRcd6Iyo54ZXXSaMVBDvLLTgSkdMsGpVV9MuZiBY8m1Mt8eRAzKteFlnYjYqK6EOA E7zgTqyPBW692QkiNKI/B9xKp5jeD76zbTcpHb4Cz3v/VwHzpRMX/NMpExPZJBQAYDI2 nclQ== X-Gm-Message-State: AOJu0YwHBZ8DksegPbrHq74/BW+Ar0+S8N74cRWNXdimsc0Re6Wi4GwU MnOECFZBET9JECa9YYEc4F5b765NcaDNa4ogsuHzaHWhoqc8Z8iZSPNkV60zqzdr3Kl9/Z8P23n HP4uH X-Gm-Gg: AZuq6aJ3NR9CT4TxedJaqmSUzCltiMuGJpZ8+Bov4GE03GDYuNPCjXLU4mJaR8y33X0 CbqNNa5UhsNnNdvbFRgcgGTflPtjN7g3KpvgSK+UuZnKfd0ssfCIqjmeYRnlmmgcuYHushDCbrq jytne41H3pzaunzVu5/I2tB1VONin153nBx4U3jJU46qB/3/AgHR1HCgazer66cc9eWr2RRMWau T33w8ApngeV2OeiKF8EaF2oz1Rz20j+WGkgkK9aOkAkGC6QM47ie/nxslVDvC+8qYUSAIMcnrWJ lmTH+5VyhL4+iXIYaey5x4JNG19RuvZWEP65Gjfw6Df0bo6QJ3g+XkKJBnt0GYteVCJSnoFHvA7 NfzwOAQ9Jri1+VQ/IaEL34HenzmArml1pE4dBqNwcwlxeetJgwbQAz1ZzeAoS4s6JBmyYvU4u4P ic6ojnx228RKWgmN9JD10boMSh X-Received: by 2002:a05:600c:1e1d:b0:483:456a:514b with SMTP id 5b1f17b1804b1-483a95befe5mr129473145e9.12.1771840299027; Mon, 23 Feb 2026 01:51:39 -0800 (PST) Received: from localhost ([85.163.81.98]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-483a31b3e0dsm397848795e9.1.2026.02.23.01.51.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 23 Feb 2026 01:51:38 -0800 (PST) From: Jiri Pirko To: dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, iommu@lists.linux.dev, linux-media@vger.kernel.org Cc: sumit.semwal@linaro.org, benjamin.gaignard@collabora.com, Brian.Starkey@arm.com, jstultz@google.com, tjmercier@google.com, christian.koenig@amd.com, m.szyprowski@samsung.com, robin.murphy@arm.com, jgg@ziepe.ca, leon@kernel.org, sean.anderson@linux.dev, ptesarik@suse.com, catalin.marinas@arm.com, aneesh.kumar@kernel.org, suzuki.poulose@arm.com, steven.price@arm.com, thomas.lendacky@amd.com, john.allen@amd.com, ashish.kalra@amd.com, suravee.suthikulpanit@amd.com, linux-coco@lists.linux.dev Subject: [PATCH v2 1/2] dma-mapping: introduce DMA_ATTR_CC_DECRYPTED for pre-decrypted memory Date: Mon, 23 Feb 2026 10:51:35 +0100 Message-ID: <20260223095136.225277-2-jiri@resnulli.us> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20260223095136.225277-1-jiri@resnulli.us> References: <20260223095136.225277-1-jiri@resnulli.us> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" From: Jiri Pirko Current CC designs don't place a vIOMMU in front of untrusted devices. Instead, the DMA API forces all untrusted device DMA through swiotlb bounce buffers (is_swiotlb_force_bounce()) which copies data into decrypted memory on behalf of the device. When a caller has already arranged for the memory to be decrypted via set_memory_decrypted(), the DMA API needs to know so it can map directly using the unencrypted physical address rather than bounce buffering. Following the pattern of DMA_ATTR_MMIO, add DMA_ATTR_CC_DECRYPTED for this purpose. Like the MMIO case, only the caller knows what kind of memory it has and must inform the DMA API for it to work correctly. Signed-off-by: Jiri Pirko --- v1->v2: - rebased on top of recent dma-mapping-fixes --- include/linux/dma-mapping.h | 6 ++++++ include/trace/events/dma.h | 3 ++- kernel/dma/direct.h | 14 +++++++++++--- 3 files changed, 19 insertions(+), 4 deletions(-) diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 29973baa0581..ae3d85e494ec 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -85,6 +85,12 @@ * a cacheline must have this attribute for this to be considered safe. */ #define DMA_ATTR_CPU_CACHE_CLEAN (1UL << 11) +/* + * DMA_ATTR_CC_DECRYPTED: Indicates memory that has been explicitly decrypted + * (shared) for confidential computing guests. The caller must have + * called set_memory_decrypted(). A struct page is required. + */ +#define DMA_ATTR_CC_DECRYPTED (1UL << 12) /* * A dma_addr_t can hold any valid DMA or bus address for the platform. It can diff --git a/include/trace/events/dma.h b/include/trace/events/dma.h index 33e99e792f1a..b8082d5177c4 100644 --- a/include/trace/events/dma.h +++ b/include/trace/events/dma.h @@ -32,7 +32,8 @@ TRACE_DEFINE_ENUM(DMA_NONE); { DMA_ATTR_ALLOC_SINGLE_PAGES, "ALLOC_SINGLE_PAGES" }, \ { DMA_ATTR_NO_WARN, "NO_WARN" }, \ { DMA_ATTR_PRIVILEGED, "PRIVILEGED" }, \ - { DMA_ATTR_MMIO, "MMIO" }) + { DMA_ATTR_MMIO, "MMIO" }, \ + { DMA_ATTR_CC_DECRYPTED, "CC_DECRYPTED" }) DECLARE_EVENT_CLASS(dma_map, TP_PROTO(struct device *dev, phys_addr_t phys_addr, dma_addr_t dma_addr, diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h index e89f175e9c2d..c047a9d0fda3 100644 --- a/kernel/dma/direct.h +++ b/kernel/dma/direct.h @@ -84,16 +84,24 @@ static inline dma_addr_t dma_direct_map_phys(struct device *dev, dma_addr_t dma_addr; if (is_swiotlb_force_bounce(dev)) { - if (attrs & DMA_ATTR_MMIO) - return DMA_MAPPING_ERROR; + if (!(attrs & DMA_ATTR_CC_DECRYPTED)) { + if (attrs & DMA_ATTR_MMIO) + return DMA_MAPPING_ERROR; - return swiotlb_map(dev, phys, size, dir, attrs); + return swiotlb_map(dev, phys, size, dir, attrs); + } + } else if (attrs & DMA_ATTR_CC_DECRYPTED) { + return DMA_MAPPING_ERROR; } if (attrs & DMA_ATTR_MMIO) { dma_addr = phys; if (unlikely(!dma_capable(dev, dma_addr, size, false))) goto err_overflow; + } else if (attrs & DMA_ATTR_CC_DECRYPTED) { + dma_addr = phys_to_dma_unencrypted(dev, phys); + if (unlikely(!dma_capable(dev, dma_addr, size, false))) + goto err_overflow; } else { dma_addr = phys_to_dma(dev, phys); if (unlikely(!dma_capable(dev, dma_addr, size, true)) || -- 2.51.1