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 A86AEE81BDB for ; Mon, 9 Feb 2026 15:38:17 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id AA08710E41E; Mon, 9 Feb 2026 15:38:16 +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="HULoymcN"; dkim-atps=neutral Received: from mail-wr1-f43.google.com (mail-wr1-f43.google.com [209.85.221.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id 29FA110E41B for ; Mon, 9 Feb 2026 15:38:14 +0000 (UTC) Received: by mail-wr1-f43.google.com with SMTP id ffacd0b85a97d-436309f1ad7so1886356f8f.3 for ; Mon, 09 Feb 2026 07:38:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=resnulli-us.20230601.gappssmtp.com; s=20230601; t=1770651493; x=1771256293; 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=10eo7Xx3UsXznodXP/t6JgtysFzGllvuxfjnxVYXEzw=; b=HULoymcN7dtcuddup6tunDBvPqPvxHikW3601pwmluqHcyGc1zhRKlW3Mx55OZt1LW PNQWO24pyX/il7MLcYEpmzKz58W0GZNoeAk99jKQh1GSiA+qFdPEXjJpjgLCCKblgMWj sjqubgz6PrMzFGTB991YdpzUwcbZVazyuOceQHx16WtD+hwtBwctLIHXmmseBS6lr+s5 OOhZdwA+mh7jIg3ei2LXwIs9fRQRh7lAQYxzjbzFzu47JhR84hjAmDTj9sIaiarvNvKQ KGXg9TJgOBgg+PHJtlDwb7BQLATJV1VbETHuIEPEYQknO9FBBGLr5X5/fYqVYBjKEMbw 9AdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770651493; x=1771256293; 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=10eo7Xx3UsXznodXP/t6JgtysFzGllvuxfjnxVYXEzw=; b=Jv4sK4DNYv1++UPWZ3AovtqB3R2emEJBdTobM8hsOmN8neX66cgjPPn30uTv697EwI QMU13wTkUiIvBYzdHiiXxMENLPOzQoYR+MertVw7e26ysiD6TwDTpiNKS6dPrnAe6MfZ Fnrk82kH6brPiNZCFm0kGAiVgA+8W4wEN2EgMSL/f2zRBbVDFsrFf1y36hbFXSLLcZ7P kCuTnQwHlD9x1WRo7KlW4GEoKpbFzm5x54c78QI1R5z6jPdXvvp4Vpcqr+QcPMx6Io1o NwbSPRBThy3XN/je0A0AF7S0KyVqfZrkJztzBDIfQXhQIXnugDdoSMvkd3VVc11jBFGd q5Qw== X-Gm-Message-State: AOJu0YywUclXU0ra6l0T1eOFxik342AexlwJztycXuX/sRArVFnNA4IL iVFZfo47QmBg+I5C1BbderbrdIV2ExMvVOrBbWEltiYfKy/+sCkl6Kj8SUbBbSw62OY6L53v3dV ATb1s X-Gm-Gg: AZuq6aJaDAiQKzFusu5Z1DkhQ5gPdhjUwtEoPvQeH6TOEtrceVeeUnLp38jDUBik6rq 6xw30gCKbmeLXplktfzM/DuScsHBnDxMVe/hCn1NR6ifZNokZMjebSFNNkCvvh7fsjYKgjZbsdC ObLp9mMjCcJHG4jLWTIZ7rmjEFHNePrMAAdEkWxrbZo1UrIBpQ1MUDPr4InJxMoZ6TQ/v34wCat K/0M/K54izRR6EOoPy0IlwiHyzE3+1vJ9//aMEuhiK+rWFdWwkN7KX6wxwCzSNeDlelsSC7h4yl RAZnm8PvfW+rsP6y6gHSilPgdLt2D8N1cgEL1fB7z2ieGGJ/KLzbTB4JUBtJo3Tyz8+xv7Vi3V4 AULUJuQPXwNv8Ar57O5zYijr+hrEewCkB3QexibLGOquSBFv7HmQpIIADsThz8krMh8mVA8KgHZ 19/w== X-Received: by 2002:a05:6000:4211:b0:435:b755:c67e with SMTP id ffacd0b85a97d-4362938a453mr16934813f8f.49.1770651492550; Mon, 09 Feb 2026 07:38:12 -0800 (PST) Received: from localhost ([85.163.81.98]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-436296bd4a1sm27481147f8f.17.2026.02.09.07.38.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Feb 2026 07:38:12 -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 2/5] dma-mapping: introduce DMA_ATTR_CC_DECRYPTED for pre-decrypted memory Date: Mon, 9 Feb 2026 16:38:06 +0100 Message-ID: <20260209153809.250835-3-jiri@resnulli.us> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20260209153809.250835-1-jiri@resnulli.us> References: <20260209153809.250835-1-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 This is only relevant inside confidential computing (CoCo) virtual machines, not on the hypervisor side. Current CoCo 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 --- include/linux/dma-mapping.h | 7 +++++++ include/trace/events/dma.h | 3 ++- kernel/dma/direct.h | 14 +++++++++++--- 3 files changed, 20 insertions(+), 4 deletions(-) diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index aa36a0d1d9df..052235feb853 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -78,6 +78,13 @@ */ #define DMA_ATTR_MMIO (1UL << 10) +/* + * 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 << 11) + /* * A dma_addr_t can hold any valid DMA or bus address for the platform. It can * be given to a device to use as a DMA source or target. It is specific to a diff --git a/include/trace/events/dma.h b/include/trace/events/dma.h index b3fef140ae15..b3c2cee8841a 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 62f0d9d0ba02..ae5bc1919e1c 100644 --- a/kernel/dma/direct.h +++ b/kernel/dma/direct.h @@ -87,16 +87,24 @@ 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