From nobody Wed Jun 17 07:20:40 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E8C4D364EB2; Mon, 27 Apr 2026 05:55:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777269329; cv=none; b=oGrHlOVsNXBoguv1Wqu+EIAf6Ys+zAQ7NGrvWtkIJ3QZtohYJU07++bqYjXke6QHXlvmVT1jyd/g05mfqHnqMAmnfdq0Gi5tZLhDGD1GmrmFBfCDNh5Np5H1j3RA7bjTIgPDF5OCQRe5ipHo4whMPTqwvQbXZkiI1zXVa4u9enw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777269329; c=relaxed/simple; bh=3swRvyeNc5AeLtSgBuVCbdTez2sp8DKcDsxRQ7clE/A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kalosC9NgcNU3BZxj1U7y6A+htD3IBPTYVsCjLYOFDVzepmvbijtsFmzKuYRvaTN7rjLe5tPQG9AmshTy4liVXtU/me9/v6sc8Eew6vu2uEqAeOJBSxFp3R8jbEQkYOgW0TjWH7V6CoRkDthHB2I8+ZJF6sIrcc0xicMIR1PTRI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bf3wnpy1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bf3wnpy1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B5F9C4AF0E; Mon, 27 Apr 2026 05:55:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777269328; bh=3swRvyeNc5AeLtSgBuVCbdTez2sp8DKcDsxRQ7clE/A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bf3wnpy1ZnIoumufFYxQYNOjUEKIx6ypx4+OQnsHwHoLalf7AJYdoFXymltjhC9GZ eKLb/2Vwm+VVWce34ZmwNgj9051ppVvmjmGAeurLFkMB7Bnm//8Bmx2ymtomhmDCMZ ZRfvsVzCkwhag9oEUUnsylLcgrzTlRTUFZ7tXS8wmFH3ocAkHhQxsA4+OQ4/ofWJKS 5WmNoKroW8SuFwBkAajYO0vaD9bfjf8fY952PvogyR09FvqUP1XWjM9nol77f9tP1X I2OlyH5uM7axBI3xY5eU9yn3fw8tP354+vmfoV9Ul7pnf/Xs8OQoEF55TDr/HJz6Xu nR1ZeLxBWfA6g== From: "Aneesh Kumar K.V (Arm)" To: iommu@lists.linux.dev, linux-kernel@vger.kernel.org Cc: "Aneesh Kumar K.V (Arm)" , Robin Murphy , Marek Szyprowski , Will Deacon , Marc Zyngier , Steven Price , Suzuki K Poulose , Catalin Marinas , Jiri Pirko , Jason Gunthorpe , Mostafa Saleh , Petr Tesarik , Alexey Kardashevskiy , Dan Williams , Xu Yilun Subject: [PATCH v3 1/9] dma-direct: swiotlb: handle swiotlb alloc/free outside __dma_direct_alloc_pages Date: Mon, 27 Apr 2026 11:25:01 +0530 Message-ID: <20260427055509.898190-2-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260427055509.898190-1-aneesh.kumar@kernel.org> References: <20260427055509.898190-1-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-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Move swiotlb allocation out of __dma_direct_alloc_pages() and handle it in dma_direct_alloc() / dma_direct_alloc_pages(). This is needed for follow-up changes that simplify the handling of memory encryption/decryption based on the DMA attribute flags. swiotlb backing pages are already mapped decrypted by swiotlb_update_mem_attributes() and rmem_swiotlb_device_init(), so dma-direct should not call dma_set_decrypted() on allocation nor dma_set_encrypted() on free for swiotlb-backed memory. Update alloc/free paths to detect swiotlb-backed pages and skip encrypt/decrypt transitions for those paths. Keep the existing highmem rejection in dma_direct_alloc_pages() for swiotlb allocations. Only for "restricted-dma-pool", we currently set `for_alloc =3D true`, while rmem_swiotlb_device_init() decrypts the whole pool up front. This pool is typically used together with "shared-dma-pool", where the shared region is accessed after remap/ioremap and the returned address is suitable for decrypted memory access. So existing code paths remain valid. Signed-off-by: Aneesh Kumar K.V (Arm) --- kernel/dma/direct.c | 44 +++++++++++++++++++++++++++++++++++++------- 1 file changed, 37 insertions(+), 7 deletions(-) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index ec887f443741..b958f150718a 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -125,9 +125,6 @@ static struct page *__dma_direct_alloc_pages(struct dev= ice *dev, size_t size, =20 WARN_ON_ONCE(!PAGE_ALIGNED(size)); =20 - if (is_swiotlb_for_alloc(dev)) - return dma_direct_alloc_swiotlb(dev, size); - gfp |=3D dma_direct_optimal_gfp_mask(dev, &phys_limit); page =3D dma_alloc_contiguous(dev, size, gfp); if (page) { @@ -204,6 +201,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) { bool remap =3D false, set_uncached =3D false; + bool mark_mem_decrypt =3D true; struct page *page; void *ret; =20 @@ -250,11 +248,21 @@ void *dma_direct_alloc(struct device *dev, size_t siz= e, dma_direct_use_pool(dev, gfp)) return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp); =20 + if (is_swiotlb_for_alloc(dev)) { + page =3D dma_direct_alloc_swiotlb(dev, size); + if (page) { + mark_mem_decrypt =3D false; + goto setup_page; + } + return NULL; + } + /* we always manually zero the memory once we are done */ page =3D __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, true); if (!page) return NULL; =20 +setup_page: /* * dma_alloc_contiguous can return highmem pages depending on a * combination the cma=3D arguments and per-arch setup. These need to be @@ -281,7 +289,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, goto out_free_pages; } else { ret =3D page_address(page); - if (dma_set_decrypted(dev, ret, size)) + if (mark_mem_decrypt && dma_set_decrypted(dev, ret, size)) goto out_leak_pages; } =20 @@ -298,7 +306,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, return ret; =20 out_encrypt_pages: - if (dma_set_encrypted(dev, page_address(page), size)) + if (mark_mem_decrypt && dma_set_encrypted(dev, page_address(page), size)) return NULL; out_free_pages: __dma_direct_free_pages(dev, page, size); @@ -310,6 +318,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, void dma_direct_free(struct device *dev, size_t size, void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs) { + bool mark_mem_encrypted =3D true; unsigned int page_order =3D get_order(size); =20 if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) && @@ -338,12 +347,15 @@ void dma_direct_free(struct device *dev, size_t size, dma_free_from_pool(dev, cpu_addr, PAGE_ALIGN(size))) return; =20 + if (swiotlb_find_pool(dev, dma_to_phys(dev, dma_addr))) + mark_mem_encrypted =3D false; + if (is_vmalloc_addr(cpu_addr)) { vunmap(cpu_addr); } else { if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_CLEAR_UNCACHED)) arch_dma_clear_uncached(cpu_addr, size); - if (dma_set_encrypted(dev, cpu_addr, size)) + if (mark_mem_encrypted && dma_set_encrypted(dev, cpu_addr, size)) return; } =20 @@ -359,6 +371,19 @@ struct page *dma_direct_alloc_pages(struct device *dev= , size_t size, if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp)) return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp); =20 + if (is_swiotlb_for_alloc(dev)) { + page =3D dma_direct_alloc_swiotlb(dev, size); + if (!page) + return NULL; + + if (PageHighMem(page)) { + swiotlb_free(dev, page, size); + return NULL; + } + ret =3D page_address(page); + goto setup_page; + } + page =3D __dma_direct_alloc_pages(dev, size, gfp, false); if (!page) return NULL; @@ -366,6 +391,7 @@ struct page *dma_direct_alloc_pages(struct device *dev,= size_t size, ret =3D page_address(page); if (dma_set_decrypted(dev, ret, size)) goto out_leak_pages; +setup_page: memset(ret, 0, size); *dma_handle =3D phys_to_dma_direct(dev, page_to_phys(page)); return page; @@ -378,13 +404,17 @@ void dma_direct_free_pages(struct device *dev, size_t= size, enum dma_data_direction dir) { void *vaddr =3D page_address(page); + bool mark_mem_encrypted =3D true; =20 /* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */ if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) && dma_free_from_pool(dev, vaddr, size)) return; =20 - if (dma_set_encrypted(dev, vaddr, size)) + if (swiotlb_find_pool(dev, page_to_phys(page))) + mark_mem_encrypted =3D false; + + if (mark_mem_encrypted && dma_set_encrypted(dev, vaddr, size)) return; __dma_direct_free_pages(dev, page, size); } --=20 2.43.0 From nobody Wed Jun 17 07:20:40 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 783FC366563; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="B1kzbWu+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2C336C19425; Mon, 27 Apr 2026 05:55:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777269334; bh=4MW7wMvDoqITfLwkJTW6/lwo+jU4h0pFXHWOV1R6rJM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=B1kzbWu+XZa44j2kbKRsnQLPVkZaX63SB0PubV/0a3yrOpaOOVp/WEjNUq/gEEY4h DWUrrbmKcXbm7TlKwR1FBg5KyKQ37oeXAaH+FpFrSgV5Way6DHAiZrHJ4OgAnXz6Uk w48yXV6IYRRbEx7oYCAR3lPWhF0JH1S9JEFdYYKhgC1QXvGZRUkV7Hu+GgKGPYVNYA 4KJxzqzm40qnfQn+QEwvjkU2c/27uYWMDdg4bIxtwMhCgOSQAv2XXOU2Z71AnUigwO N7jR6qXZzK+re7eFazso3GYYePQ5LZ3pNlQa5uXoJzm6a27ePFvCkpyRUkPLaaqqbu c+2BS/LnffA4A== From: "Aneesh Kumar K.V (Arm)" To: iommu@lists.linux.dev, linux-kernel@vger.kernel.org Cc: "Aneesh Kumar K.V (Arm)" , Robin Murphy , Marek Szyprowski , Will Deacon , Marc Zyngier , Steven Price , Suzuki K Poulose , Catalin Marinas , Jiri Pirko , Jason Gunthorpe , Mostafa Saleh , Petr Tesarik , Alexey Kardashevskiy , Dan Williams , Xu Yilun Subject: [PATCH v3 2/9] dma-direct: use DMA_ATTR_CC_SHARED in alloc/free paths Date: Mon, 27 Apr 2026 11:25:02 +0530 Message-ID: <20260427055509.898190-3-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260427055509.898190-1-aneesh.kumar@kernel.org> References: <20260427055509.898190-1-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-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Propagate force_dma_unencrypted() into DMA_ATTR_CC_SHARED 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 | 44 ++++++++++++++++++++++++++++++++++++-------- 1 file changed, 36 insertions(+), 8 deletions(-) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index b958f150718a..0c2e1f8436ce 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -201,16 +201,31 @@ void *dma_direct_alloc(struct device *dev, size_t siz= e, dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) { bool remap =3D false, set_uncached =3D false; - bool mark_mem_decrypt =3D true; + bool mark_mem_decrypt =3D false; struct page *page; void *ret; =20 + /* + * DMA_ATTR_CC_SHARED is not a caller-visible dma_alloc_*() + * attribute. The direct allocator uses it internally after it has + * decided that the backing pages must be shared/decrypted, so the + * rest of the allocation path can consistently select DMA addresses, + * choose compatible pools and restore encryption on free. + */ + if (attrs & DMA_ATTR_CC_SHARED) + return NULL; + + if (force_dma_unencrypted(dev)) { + attrs |=3D DMA_ATTR_CC_SHARED; + mark_mem_decrypt =3D true; + } + size =3D PAGE_ALIGN(size); if (attrs & DMA_ATTR_NO_WARN) gfp |=3D __GFP_NOWARN; =20 - if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) && - !force_dma_unencrypted(dev) && !is_swiotlb_for_alloc(dev)) + if (((attrs & (DMA_ATTR_NO_KERNEL_MAPPING | DMA_ATTR_CC_SHARED)) =3D=3D + DMA_ATTR_NO_KERNEL_MAPPING) && !is_swiotlb_for_alloc(dev)) return dma_direct_alloc_no_mapping(dev, size, dma_handle, gfp); =20 if (!dev_is_dma_coherent(dev)) { @@ -244,7 +259,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, * Remapping or decrypting memory may block, allocate the memory from * the atomic pools instead if we aren't allowed block. */ - if ((remap || force_dma_unencrypted(dev)) && + if ((remap || (attrs & DMA_ATTR_CC_SHARED)) && dma_direct_use_pool(dev, gfp)) return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp); =20 @@ -318,11 +333,20 @@ void *dma_direct_alloc(struct device *dev, size_t siz= e, void dma_direct_free(struct device *dev, size_t size, void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs) { - bool mark_mem_encrypted =3D true; + bool mark_mem_encrypted =3D false; unsigned int page_order =3D get_order(size); =20 - if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) && - !force_dma_unencrypted(dev) && !is_swiotlb_for_alloc(dev)) { + /* + * if the device had requested for an unencrypted buffer, + * convert it to encrypted on free + */ + if (force_dma_unencrypted(dev)) { + attrs |=3D DMA_ATTR_CC_SHARED; + mark_mem_encrypted =3D true; + } + + if (((attrs & (DMA_ATTR_NO_KERNEL_MAPPING | DMA_ATTR_CC_SHARED)) =3D=3D + DMA_ATTR_NO_KERNEL_MAPPING) && !is_swiotlb_for_alloc(dev)) { /* cpu_addr is a struct page cookie, not a kernel address */ dma_free_contiguous(dev, cpu_addr, size); return; @@ -365,10 +389,14 @@ void dma_direct_free(struct device *dev, size_t size, struct page *dma_direct_alloc_pages(struct device *dev, size_t size, dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp) { + unsigned long attrs =3D 0; struct page *page; void *ret; =20 - if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp)) + if (force_dma_unencrypted(dev)) + attrs |=3D DMA_ATTR_CC_SHARED; + + if ((attrs & DMA_ATTR_CC_SHARED) && dma_direct_use_pool(dev, gfp)) return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp); =20 if (is_swiotlb_for_alloc(dev)) { --=20 2.43.0 From nobody Wed Jun 17 07:20:40 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 48F8534A78E; Mon, 27 Apr 2026 05:55:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777269340; cv=none; b=d3Nc5lDegI5XwHO0QTqhIgQVgfM+Gyh13IuXsv+DYikD7rrOX8kGqs26skB//UKN3s3KM3gSywQKtBlOFJSuggqiiQzwig7LtGe7VIrszeSqYpxftgfUXH0McPOqjw3f2p1UCsAc0CGMnNbfj43rF66wl1lK9ECK01BBYl1kP3Q= ARC-Message-Signature: i=1; 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b=JzmYl2uCikmBjuafeflE8Qu7R20TMdAUfqRT+yQYWxPntskOnZOEvaVIR/vwYsaG5 ooCUi9vGBsyIiqdKWTidSqVPIJ4+aUtxHLJqa904qCMwGLt52/ZNNFuWPA+O1dLaWT 1+haHgz2s0dNdIQrCDez0Nk9FCRSXpp4QW8h9xFova4BDrG+Bn+0Z6qoiLT859nF9r otE9bO0j6mRMdfbQVZkeVYOzcOazfrB2YT5Jgk717sbEFpqeip9/cCN77JJpS7rZ1W HSdcXiju9HGop7tF0rzrX9pBKryOwI3TLTrDvTLSAEssQ6mHYJ1ft3J44zq3xIHV2j BmZ9bx4gYteOQ== From: "Aneesh Kumar K.V (Arm)" To: iommu@lists.linux.dev, linux-kernel@vger.kernel.org Cc: "Aneesh Kumar K.V (Arm)" , Robin Murphy , Marek Szyprowski , Will Deacon , Marc Zyngier , Steven Price , Suzuki K Poulose , Catalin Marinas , Jiri Pirko , Jason Gunthorpe , Mostafa Saleh , Petr Tesarik , Alexey Kardashevskiy , Dan Williams , Xu Yilun Subject: [PATCH v3 3/9] dma-pool: track decrypted atomic pools and select them via attrs Date: Mon, 27 Apr 2026 11:25:03 +0530 Message-ID: <20260427055509.898190-4-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260427055509.898190-1-aneesh.kumar@kernel.org> References: <20260427055509.898190-1-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-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Teach the atomic DMA pool code to distinguish between encrypted and decrypted pools, and make pool allocation select the matching pool based on DMA attributes. Introduce a dma_gen_pool wrapper that records whether a pool is decrypted, initialize that state when the atomic pools are created, and use it when expanding and resizing the pools. Update dma_alloc_from_pool() to take attrs and skip pools whose encrypted/decrypted state does not match DMA_ATTR_CC_SHARED. Update dma_free_from_pool() accordingly. Also pass DMA_ATTR_CC_SHARED from the swiotlb atomic allocation path so decrypted swiotlb allocations are taken from the correct atomic pool. Signed-off-by: Aneesh Kumar K.V (Arm) --- drivers/iommu/dma-iommu.c | 2 +- include/linux/dma-map-ops.h | 2 +- kernel/dma/direct.c | 11 ++- kernel/dma/pool.c | 154 +++++++++++++++++++++++------------- kernel/dma/swiotlb.c | 2 + 5 files changed, 109 insertions(+), 62 deletions(-) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 54d96e847f16..c2595bee3d41 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -1673,7 +1673,7 @@ void *iommu_dma_alloc(struct device *dev, size_t size= , dma_addr_t *handle, if (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !gfpflags_allow_blocking(gfp) && !coherent) page =3D dma_alloc_from_pool(dev, PAGE_ALIGN(size), &cpu_addr, - gfp, NULL); + gfp, attrs, NULL); else cpu_addr =3D iommu_dma_alloc_pages(dev, size, &page, gfp, attrs); if (!cpu_addr) diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h index 6a1832a73cad..696b2c3a2305 100644 --- a/include/linux/dma-map-ops.h +++ b/include/linux/dma-map-ops.h @@ -212,7 +212,7 @@ void *dma_common_pages_remap(struct page **pages, size_= t size, pgprot_t prot, void dma_common_free_remap(void *cpu_addr, size_t size); =20 struct page *dma_alloc_from_pool(struct device *dev, size_t size, - void **cpu_addr, gfp_t flags, + void **cpu_addr, gfp_t flags, unsigned long attrs, bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t)); bool dma_free_from_pool(struct device *dev, void *start, size_t size); =20 diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 0c2e1f8436ce..707d410b3669 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -162,7 +162,7 @@ static bool dma_direct_use_pool(struct device *dev, gfp= _t gfp) } =20 static void *dma_direct_alloc_from_pool(struct device *dev, size_t size, - dma_addr_t *dma_handle, gfp_t gfp) + dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) { struct page *page; u64 phys_limit; @@ -172,7 +172,8 @@ static void *dma_direct_alloc_from_pool(struct device *= dev, size_t size, return NULL; =20 gfp |=3D dma_direct_optimal_gfp_mask(dev, &phys_limit); - page =3D dma_alloc_from_pool(dev, size, &ret, gfp, dma_coherent_ok); + page =3D dma_alloc_from_pool(dev, size, &ret, gfp, attrs, + dma_coherent_ok); if (!page) return NULL; *dma_handle =3D phys_to_dma_direct(dev, page_to_phys(page)); @@ -261,7 +262,8 @@ void *dma_direct_alloc(struct device *dev, size_t size, */ if ((remap || (attrs & DMA_ATTR_CC_SHARED)) && dma_direct_use_pool(dev, gfp)) - return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp); + return dma_direct_alloc_from_pool(dev, size, dma_handle, + gfp, attrs); =20 if (is_swiotlb_for_alloc(dev)) { page =3D dma_direct_alloc_swiotlb(dev, size); @@ -397,7 +399,8 @@ struct page *dma_direct_alloc_pages(struct device *dev,= size_t size, attrs |=3D DMA_ATTR_CC_SHARED; =20 if ((attrs & DMA_ATTR_CC_SHARED) && dma_direct_use_pool(dev, gfp)) - return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp); + return dma_direct_alloc_from_pool(dev, size, dma_handle, + gfp, attrs); =20 if (is_swiotlb_for_alloc(dev)) { page =3D dma_direct_alloc_swiotlb(dev, size); diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c index 2b2fbb709242..e41e19701e50 100644 --- a/kernel/dma/pool.c +++ b/kernel/dma/pool.c @@ -12,12 +12,18 @@ #include #include #include +#include =20 -static struct gen_pool *atomic_pool_dma __ro_after_init; +struct dma_gen_pool { + bool decrypted; + struct gen_pool *pool; +}; + +static struct dma_gen_pool atomic_pool_dma __ro_after_init; static unsigned long pool_size_dma; -static struct gen_pool *atomic_pool_dma32 __ro_after_init; +static struct dma_gen_pool atomic_pool_dma32 __ro_after_init; static unsigned long pool_size_dma32; -static struct gen_pool *atomic_pool_kernel __ro_after_init; +static struct dma_gen_pool atomic_pool_kernel __ro_after_init; static unsigned long pool_size_kernel; =20 /* Size can be defined by the coherent_pool command line */ @@ -76,7 +82,7 @@ static bool cma_in_zone(gfp_t gfp) return true; } =20 -static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, +static int atomic_pool_expand(struct dma_gen_pool *dma_pool, size_t pool_s= ize, gfp_t gfp) { unsigned int order; @@ -113,11 +119,14 @@ static int atomic_pool_expand(struct gen_pool *pool, = size_t pool_size, * Memory in the atomic DMA pools must be unencrypted, the pools do not * shrink so no re-encryption occurs in dma_direct_free(). */ - ret =3D set_memory_decrypted((unsigned long)page_to_virt(page), + if (dma_pool->decrypted) { + ret =3D set_memory_decrypted((unsigned long)page_to_virt(page), 1 << order); - if (ret) - goto remove_mapping; - ret =3D gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page), + if (ret) + goto remove_mapping; + } + + ret =3D gen_pool_add_virt(dma_pool->pool, (unsigned long)addr, page_to_ph= ys(page), pool_size, NUMA_NO_NODE); if (ret) goto encrypt_mapping; @@ -126,11 +135,13 @@ static int atomic_pool_expand(struct gen_pool *pool, = size_t pool_size, return 0; =20 encrypt_mapping: - ret =3D set_memory_encrypted((unsigned long)page_to_virt(page), - 1 << order); - if (WARN_ON_ONCE(ret)) { - /* Decrypt succeeded but encrypt failed, purposely leak */ - goto out; + if (dma_pool->decrypted) { + ret =3D set_memory_encrypted((unsigned long)page_to_virt(page), + 1 << order); + if (WARN_ON_ONCE(ret)) { + /* Decrypt succeeded but encrypt failed, purposely leak */ + goto out; + } } remove_mapping: #ifdef CONFIG_DMA_DIRECT_REMAP @@ -142,46 +153,51 @@ static int atomic_pool_expand(struct gen_pool *pool, = size_t pool_size, return ret; } =20 -static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp) +static void atomic_pool_resize(struct dma_gen_pool *dma_pool, gfp_t gfp) { - if (pool && gen_pool_avail(pool) < atomic_pool_size) - atomic_pool_expand(pool, gen_pool_size(pool), gfp); + if (dma_pool->pool && gen_pool_avail(dma_pool->pool) < atomic_pool_size) + atomic_pool_expand(dma_pool, gen_pool_size(dma_pool->pool), gfp); } =20 static void atomic_pool_work_fn(struct work_struct *work) { if (IS_ENABLED(CONFIG_ZONE_DMA)) - atomic_pool_resize(atomic_pool_dma, + atomic_pool_resize(&atomic_pool_dma, GFP_KERNEL | GFP_DMA); if (IS_ENABLED(CONFIG_ZONE_DMA32)) - atomic_pool_resize(atomic_pool_dma32, + atomic_pool_resize(&atomic_pool_dma32, GFP_KERNEL | GFP_DMA32); - atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL); + atomic_pool_resize(&atomic_pool_kernel, GFP_KERNEL); } =20 -static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size, - gfp_t gfp) +static __init struct dma_gen_pool *__dma_atomic_pool_init(struct dma_gen_p= ool *dma_pool, + size_t pool_size, gfp_t gfp) { - struct gen_pool *pool; int ret; =20 - pool =3D gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE); - if (!pool) + dma_pool->pool =3D gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE); + if (!dma_pool->pool) return NULL; =20 - gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL); + gen_pool_set_algo(dma_pool->pool, gen_pool_first_fit_order_align, NULL); + + /* if platform is using memory encryption atomic pools are by default dec= rypted. */ + if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) + dma_pool->decrypted =3D true; + else + dma_pool->decrypted =3D false; =20 - ret =3D atomic_pool_expand(pool, pool_size, gfp); + ret =3D atomic_pool_expand(dma_pool, pool_size, gfp); if (ret) { - gen_pool_destroy(pool); + gen_pool_destroy(dma_pool->pool); pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\= n", pool_size >> 10, &gfp); return NULL; } =20 pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n", - gen_pool_size(pool) >> 10, &gfp); - return pool; + gen_pool_size(dma_pool->pool) >> 10, &gfp); + return dma_pool; } =20 #ifdef CONFIG_ZONE_DMA32 @@ -207,21 +223,22 @@ static int __init dma_atomic_pool_init(void) =20 /* All memory might be in the DMA zone(s) to begin with */ if (has_managed_zone(ZONE_NORMAL)) { - atomic_pool_kernel =3D __dma_atomic_pool_init(atomic_pool_size, - GFP_KERNEL); - if (!atomic_pool_kernel) + __dma_atomic_pool_init(&atomic_pool_kernel, atomic_pool_size, GFP_KERNEL= ); + if (!atomic_pool_kernel.pool) ret =3D -ENOMEM; } + if (has_managed_dma()) { - atomic_pool_dma =3D __dma_atomic_pool_init(atomic_pool_size, - GFP_KERNEL | GFP_DMA); - if (!atomic_pool_dma) + __dma_atomic_pool_init(&atomic_pool_dma, atomic_pool_size, + GFP_KERNEL | GFP_DMA); + if (!atomic_pool_dma.pool) ret =3D -ENOMEM; } + if (has_managed_dma32) { - atomic_pool_dma32 =3D __dma_atomic_pool_init(atomic_pool_size, - GFP_KERNEL | GFP_DMA32); - if (!atomic_pool_dma32) + __dma_atomic_pool_init(&atomic_pool_dma32, atomic_pool_size, + GFP_KERNEL | GFP_DMA32); + if (!atomic_pool_dma32.pool) ret =3D -ENOMEM; } =20 @@ -230,19 +247,38 @@ static int __init dma_atomic_pool_init(void) } postcore_initcall(dma_atomic_pool_init); =20 -static inline struct gen_pool *dma_guess_pool(struct gen_pool *prev, gfp_t= gfp) +static inline struct dma_gen_pool *dma_guess_pool(struct dma_gen_pool *pre= v, gfp_t gfp) { if (prev =3D=3D NULL) { - if (gfp & GFP_DMA) - return atomic_pool_dma ?: atomic_pool_dma32 ?: atomic_pool_kernel; - if (gfp & GFP_DMA32) - return atomic_pool_dma32 ?: atomic_pool_dma ?: atomic_pool_kernel; - return atomic_pool_kernel ?: atomic_pool_dma32 ?: atomic_pool_dma; + if (gfp & GFP_DMA) { + if (atomic_pool_dma.pool) + return &atomic_pool_dma; + if (atomic_pool_dma32.pool) + return &atomic_pool_dma32; + return &atomic_pool_kernel; + } + + if (gfp & GFP_DMA32) { + if (atomic_pool_dma32.pool) + return &atomic_pool_dma32; + if (atomic_pool_dma.pool) + return &atomic_pool_dma; + return &atomic_pool_kernel; + } + if (atomic_pool_kernel.pool) + return &atomic_pool_kernel; + if (atomic_pool_dma32.pool) + return &atomic_pool_dma32; + if (atomic_pool_dma.pool) + return &atomic_pool_dma; } - if (prev =3D=3D atomic_pool_kernel) - return atomic_pool_dma32 ? atomic_pool_dma32 : atomic_pool_dma; - if (prev =3D=3D atomic_pool_dma32) - return atomic_pool_dma; + if (prev =3D=3D &atomic_pool_kernel) { + if (atomic_pool_dma32.pool) + return &atomic_pool_dma32; + return &atomic_pool_dma; + } + if (prev =3D=3D &atomic_pool_dma32) + return &atomic_pool_dma; return NULL; } =20 @@ -272,16 +308,20 @@ static struct page *__dma_alloc_from_pool(struct devi= ce *dev, size_t size, } =20 struct page *dma_alloc_from_pool(struct device *dev, size_t size, - void **cpu_addr, gfp_t gfp, + void **cpu_addr, gfp_t gfp, unsigned long attrs, bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t)) { - struct gen_pool *pool =3D NULL; + struct dma_gen_pool *dma_pool =3D NULL; struct page *page; bool pool_found =3D false; =20 - while ((pool =3D dma_guess_pool(pool, gfp))) { + while ((dma_pool =3D dma_guess_pool(dma_pool, gfp))) { + + if (dma_pool->decrypted !=3D !!(attrs & DMA_ATTR_CC_SHARED)) + continue; + pool_found =3D true; - page =3D __dma_alloc_from_pool(dev, size, pool, cpu_addr, + page =3D __dma_alloc_from_pool(dev, size, dma_pool->pool, cpu_addr, phys_addr_ok); if (page) return page; @@ -296,12 +336,14 @@ struct page *dma_alloc_from_pool(struct device *dev, = size_t size, =20 bool dma_free_from_pool(struct device *dev, void *start, size_t size) { - struct gen_pool *pool =3D NULL; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SK3CNaH+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A4B78C2BCB7; Mon, 27 Apr 2026 05:55:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777269345; bh=U0ns5F/mbkHG2oJZkVqsPzv+Ectf0NCfJnLo68xgoXY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SK3CNaH+QoBVxyDqxlDoIcQ7e484XpXEfKsB3epWM+7+gEotFi3F3uGKcd0qPTXEA 3IEW3viJDy5uGeOFmTdXzX4BONZQzv68VnZskdISZkkyn5GTlySSTD7fm2w6hQniuL P8inGez2XSJNuQQVI46DtOSDOLJl1WyNchXMpq097kctMU9gOb4NM8DqHdzPK18SA5 uxaKNFcSrxKIIwV1qbjCZtEyAGUiIHRFvEjGljKH24ch5OORIWVQ7mHhZluS5sYff9 1eNm5U0sWNBNppmdrxd859vWyubNbCd/qOKsk8GcfReYTOVXixJR2FDyQYDoFYxX1u LuJujzr3p8z2Q== From: "Aneesh Kumar K.V (Arm)" To: iommu@lists.linux.dev, linux-kernel@vger.kernel.org Cc: "Aneesh Kumar K.V (Arm)" , Robin Murphy , Marek Szyprowski , Will Deacon , Marc Zyngier , Steven Price , Suzuki K Poulose , Catalin Marinas , Jiri Pirko , Jason Gunthorpe , Mostafa Saleh , Petr Tesarik , Alexey Kardashevskiy , Dan Williams , Xu Yilun Subject: [PATCH v3 4/9] dma: swiotlb: track pool encryption state and honor DMA_ATTR_CC_SHARED Date: Mon, 27 Apr 2026 11:25:04 +0530 Message-ID: <20260427055509.898190-5-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260427055509.898190-1-aneesh.kumar@kernel.org> References: <20260427055509.898190-1-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-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Teach swiotlb to distinguish between encrypted and decrypted bounce buffer pools, and make allocation and mapping paths select a pool whose state matches the requested DMA attributes. Add a decrypted flag to io_tlb_mem, initialize it for the default and restricted pools, and propagate DMA_ATTR_CC_SHARED into swiotlb pool allocation. Reject swiotlb alloc/map requests when the selected pool does not match the required encrypted/decrypted state. Also return DMA addresses with the matching phys_to_dma_{encrypted, unencrypted} helper so the DMA address encoding stays consistent with the chosen pool. Signed-off-by: Aneesh Kumar K.V (Arm) --- include/linux/dma-direct.h | 10 +++++ include/linux/swiotlb.h | 7 ++- kernel/dma/direct.c | 14 ++++-- kernel/dma/swiotlb.c | 89 ++++++++++++++++++++++++++++++-------- 4 files changed, 95 insertions(+), 25 deletions(-) diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h index c249912456f9..94fad4e7c11e 100644 --- a/include/linux/dma-direct.h +++ b/include/linux/dma-direct.h @@ -77,6 +77,10 @@ static inline dma_addr_t dma_range_map_max(const struct = bus_dma_region *map) #ifndef phys_to_dma_unencrypted #define phys_to_dma_unencrypted phys_to_dma #endif + +#ifndef phys_to_dma_encrypted +#define phys_to_dma_encrypted phys_to_dma +#endif #else static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t pad= dr) { @@ -90,6 +94,12 @@ static inline dma_addr_t phys_to_dma_unencrypted(struct = device *dev, { return dma_addr_unencrypted(__phys_to_dma(dev, paddr)); } + +static inline dma_addr_t phys_to_dma_encrypted(struct device *dev, + phys_addr_t paddr) +{ + return dma_addr_encrypted(__phys_to_dma(dev, paddr)); +} /* * If memory encryption is supported, phys_to_dma will set the memory encr= yption * bit in the DMA address, and dma_to_phys will clear it. diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index 3dae0f592063..382753ba3f06 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -111,6 +111,7 @@ struct io_tlb_mem { struct dentry *debugfs; bool force_bounce; bool for_alloc; + bool decrypted; #ifdef CONFIG_SWIOTLB_DYNAMIC bool can_grow; u64 phys_limit; @@ -282,7 +283,8 @@ static inline void swiotlb_sync_single_for_cpu(struct d= evice *dev, extern void swiotlb_print_info(void); =20 #ifdef CONFIG_DMA_RESTRICTED_POOL -struct page *swiotlb_alloc(struct device *dev, size_t size); +struct page *swiotlb_alloc(struct device *dev, size_t size, + unsigned long attrs); bool swiotlb_free(struct device *dev, struct page *page, size_t size); =20 static inline bool is_swiotlb_for_alloc(struct device *dev) @@ -290,7 +292,8 @@ static inline bool is_swiotlb_for_alloc(struct device *= dev) return dev->dma_io_tlb_mem->for_alloc; } #else -static inline struct page *swiotlb_alloc(struct device *dev, size_t size) +static inline struct page *swiotlb_alloc(struct device *dev, size_t size, + unsigned long attrs) { return NULL; } diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 707d410b3669..9373b9dcfb7b 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -104,9 +104,10 @@ static void __dma_direct_free_pages(struct device *dev= , struct page *page, dma_free_contiguous(dev, page, size); } =20 -static struct page *dma_direct_alloc_swiotlb(struct device *dev, size_t si= ze) +static struct page *dma_direct_alloc_swiotlb(struct device *dev, size_t si= ze, + unsigned long attrs) { - struct page *page =3D swiotlb_alloc(dev, size); + struct page *page =3D swiotlb_alloc(dev, size, attrs); =20 if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) { swiotlb_free(dev, page, size); @@ -266,8 +267,12 @@ void *dma_direct_alloc(struct device *dev, size_t size, gfp, attrs); =20 if (is_swiotlb_for_alloc(dev)) { - page =3D dma_direct_alloc_swiotlb(dev, size); + page =3D dma_direct_alloc_swiotlb(dev, size, attrs); if (page) { + /* + * swiotlb allocations comes from pool already marked + * decrypted + */ mark_mem_decrypt =3D false; goto setup_page; } @@ -374,6 +379,7 @@ void dma_direct_free(struct device *dev, size_t size, return; =20 if (swiotlb_find_pool(dev, dma_to_phys(dev, dma_addr))) + /* Swiotlb doesn't need a page attribute update on free */ mark_mem_encrypted =3D false; =20 if (is_vmalloc_addr(cpu_addr)) { @@ -403,7 +409,7 @@ struct page *dma_direct_alloc_pages(struct device *dev,= size_t size, gfp, attrs); =20 if (is_swiotlb_for_alloc(dev)) { - page =3D dma_direct_alloc_swiotlb(dev, size); + page =3D dma_direct_alloc_swiotlb(dev, size, attrs); if (!page) return NULL; =20 diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index b215b274a873..dad351988daf 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -262,7 +262,18 @@ void __init swiotlb_update_mem_attributes(void) if (!mem->nslabs || mem->late_alloc) return; bytes =3D PAGE_ALIGN(mem->nslabs << IO_TLB_SHIFT); - set_memory_decrypted((unsigned long)mem->vaddr, bytes >> PAGE_SHIFT); + /* + * if platform support memory encryption, swiotlb buffers are + * decrypted by default. + */ + if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) { + io_tlb_default_mem.decrypted =3D true; + set_memory_decrypted((unsigned long)mem->vaddr, bytes >> PAGE_SHIFT); + } else { + io_tlb_default_mem.decrypted =3D false; + } + + } =20 static void swiotlb_init_io_tlb_pool(struct io_tlb_pool *mem, phys_addr_t = start, @@ -505,8 +516,10 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask, if (!mem->slots) goto error_slots; =20 - set_memory_decrypted((unsigned long)vstart, - (nslabs << IO_TLB_SHIFT) >> PAGE_SHIFT); + if (io_tlb_default_mem.decrypted) + set_memory_decrypted((unsigned long)vstart, + (nslabs << IO_TLB_SHIFT) >> PAGE_SHIFT); + swiotlb_init_io_tlb_pool(mem, virt_to_phys(vstart), nslabs, true, nareas); add_mem_pool(&io_tlb_default_mem, mem); @@ -570,7 +583,8 @@ void __init swiotlb_exit(void) * Return: Decrypted pages, %NULL on allocation failure, or ERR_PTR(-EAGAI= N) * if the allocated physical address was above @phys_limit. */ -static struct page *alloc_dma_pages(gfp_t gfp, size_t bytes, u64 phys_limi= t) +static struct page *alloc_dma_pages(gfp_t gfp, size_t bytes, + u64 phys_limit, bool unencrypted) { unsigned int order =3D get_order(bytes); struct page *page; @@ -588,13 +602,13 @@ static struct page *alloc_dma_pages(gfp_t gfp, size_t= bytes, u64 phys_limit) } =20 vaddr =3D phys_to_virt(paddr); - if (set_memory_decrypted((unsigned long)vaddr, PFN_UP(bytes))) + if (unencrypted && set_memory_decrypted((unsigned long)vaddr, PFN_UP(byte= s))) goto error; return page; =20 error: /* Intentional leak if pages cannot be encrypted again. */ - if (!set_memory_encrypted((unsigned long)vaddr, PFN_UP(bytes))) + if (unencrypted && !set_memory_encrypted((unsigned long)vaddr, PFN_UP(byt= es))) __free_pages(page, order); return NULL; } @@ -604,12 +618,13 @@ static struct page *alloc_dma_pages(gfp_t gfp, size_t= bytes, u64 phys_limit) * @dev: Device for which a memory pool is allocated. * @bytes: Size of the buffer. * @phys_limit: Maximum allowed physical address of the buffer. + * @attrs: DMA attributes for the allocation. * @gfp: GFP flags for the allocation. * * Return: Allocated pages, or %NULL on allocation failure. */ static struct page *swiotlb_alloc_tlb(struct device *dev, size_t bytes, - u64 phys_limit, gfp_t gfp) + u64 phys_limit, unsigned long attrs, gfp_t gfp) { struct page *page; =20 @@ -617,7 +632,7 @@ static struct page *swiotlb_alloc_tlb(struct device *de= v, size_t bytes, * Allocate from the atomic pools if memory is encrypted and * the allocation is atomic, because decrypting may block. */ - if (!gfpflags_allow_blocking(gfp) && dev && force_dma_unencrypted(dev)) { + if (!gfpflags_allow_blocking(gfp) && (attrs & DMA_ATTR_CC_SHARED)) { void *vaddr; =20 if (!IS_ENABLED(CONFIG_DMA_COHERENT_POOL)) @@ -625,8 +640,7 @@ static struct page *swiotlb_alloc_tlb(struct device *de= v, size_t bytes, =20 /* considered decrypted by default */ return dma_alloc_from_pool(dev, bytes, &vaddr, gfp, - DMA_ATTR_CC_SHARED, - dma_coherent_ok); + attrs, dma_coherent_ok); } =20 gfp &=3D ~GFP_ZONEMASK; @@ -635,7 +649,8 @@ static struct page *swiotlb_alloc_tlb(struct device *de= v, size_t bytes, else if (phys_limit <=3D DMA_BIT_MASK(32)) gfp |=3D __GFP_DMA32; =20 - while (IS_ERR(page =3D alloc_dma_pages(gfp, bytes, phys_limit))) { + while (IS_ERR(page =3D alloc_dma_pages(gfp, bytes, phys_limit, + !!(attrs & DMA_ATTR_CC_SHARED)))) { if (IS_ENABLED(CONFIG_ZONE_DMA32) && phys_limit < DMA_BIT_MASK(64) && !(gfp & (__GFP_DMA32 | __GFP_DMA))) @@ -673,6 +688,7 @@ static void swiotlb_free_tlb(void *vaddr, size_t bytes) * @nslabs: Desired (maximum) number of slabs. * @nareas: Number of areas. * @phys_limit: Maximum DMA buffer physical address. + * @attrs: DMA attributes for the allocation. * @gfp: GFP flags for the allocations. * * Allocate and initialize a new IO TLB memory pool. The actual number of @@ -683,7 +699,8 @@ static void swiotlb_free_tlb(void *vaddr, size_t bytes) */ static struct io_tlb_pool *swiotlb_alloc_pool(struct device *dev, unsigned long minslabs, unsigned long nslabs, - unsigned int nareas, u64 phys_limit, gfp_t gfp) + unsigned int nareas, u64 phys_limit, unsigned long attrs, + gfp_t gfp) { struct io_tlb_pool *pool; unsigned int slot_order; @@ -703,7 +720,7 @@ static struct io_tlb_pool *swiotlb_alloc_pool(struct de= vice *dev, pool->areas =3D (void *)pool + sizeof(*pool); =20 tlb_size =3D nslabs << IO_TLB_SHIFT; - while (!(tlb =3D swiotlb_alloc_tlb(dev, tlb_size, phys_limit, gfp))) { + while (!(tlb =3D swiotlb_alloc_tlb(dev, tlb_size, phys_limit, attrs, gfp)= )) { if (nslabs <=3D minslabs) goto error_tlb; nslabs =3D ALIGN(nslabs >> 1, IO_TLB_SEGSIZE); @@ -739,7 +756,9 @@ static void swiotlb_dyn_alloc(struct work_struct *work) struct io_tlb_pool *pool; =20 pool =3D swiotlb_alloc_pool(NULL, IO_TLB_MIN_SLABS, default_nslabs, - default_nareas, mem->phys_limit, GFP_KERNEL); + default_nareas, mem->phys_limit, + mem->decrypted ? DMA_ATTR_CC_SHARED : 0, + GFP_KERNEL); if (!pool) { pr_warn_ratelimited("Failed to allocate new pool"); return; @@ -1229,6 +1248,7 @@ static int swiotlb_find_slots(struct device *dev, phy= s_addr_t orig_addr, nslabs =3D nr_slots(alloc_size); phys_limit =3D min_not_zero(*dev->dma_mask, dev->bus_dma_limit); pool =3D swiotlb_alloc_pool(dev, nslabs, nslabs, 1, phys_limit, + mem->decrypted ? DMA_ATTR_CC_SHARED : 0, GFP_NOWAIT); if (!pool) return -1; @@ -1391,6 +1411,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev= , phys_addr_t orig_addr, enum dma_data_direction dir, unsigned long attrs) { struct io_tlb_mem *mem =3D dev->dma_io_tlb_mem; + bool require_decrypted =3D false; unsigned int offset; struct io_tlb_pool *pool; unsigned int i; @@ -1408,6 +1429,17 @@ phys_addr_t swiotlb_tbl_map_single(struct device *de= v, phys_addr_t orig_addr, if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) pr_warn_once("Memory encryption is active and system is using DMA bounce= buffers\n"); =20 + /* + * if we are trying to swiotlb map a decrypted paddr or the paddr is encr= ypted + * but the device is forcing decryption, use decrypted io_tlb_mem + */ + if ((attrs & DMA_ATTR_CC_SHARED) || + (!(attrs & DMA_ATTR_CC_SHARED) && force_dma_unencrypted(dev))) + require_decrypted =3D true; + + if (require_decrypted !=3D mem->decrypted) + return (phys_addr_t)DMA_MAPPING_ERROR; + /* * The default swiotlb memory pool is allocated with PAGE_SIZE * alignment. If a mapping is requested with larger alignment, @@ -1605,8 +1637,14 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr= _t paddr, size_t size, if (swiotlb_addr =3D=3D (phys_addr_t)DMA_MAPPING_ERROR) return DMA_MAPPING_ERROR; =20 - /* Ensure that the address returned is DMA'ble */ - dma_addr =3D phys_to_dma_unencrypted(dev, swiotlb_addr); + /* + * Use the allocated io_tlb_mem encryption type to determine dma addr. + */ + if (dev->dma_io_tlb_mem->decrypted) + dma_addr =3D phys_to_dma_unencrypted(dev, swiotlb_addr); + else + dma_addr =3D phys_to_dma_encrypted(dev, swiotlb_addr); + if (unlikely(!dma_capable(dev, dma_addr, size, true))) { __swiotlb_tbl_unmap_single(dev, swiotlb_addr, size, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC, @@ -1770,7 +1808,8 @@ static inline void swiotlb_create_debugfs_files(struc= t io_tlb_mem *mem, =20 #ifdef CONFIG_DMA_RESTRICTED_POOL =20 -struct page *swiotlb_alloc(struct device *dev, size_t size) +struct page *swiotlb_alloc(struct device *dev, size_t size, + unsigned long attrs) { struct io_tlb_mem *mem =3D dev->dma_io_tlb_mem; struct io_tlb_pool *pool; @@ -1781,6 +1820,9 @@ struct page *swiotlb_alloc(struct device *dev, size_t= size) if (!mem) return NULL; =20 + if (mem->decrypted !=3D !!(attrs & DMA_ATTR_CC_SHARED)) + return NULL; + align =3D (1 << (get_order(size) + PAGE_SHIFT)) - 1; index =3D swiotlb_find_slots(dev, 0, size, align, &pool); if (index =3D=3D -1) @@ -1850,9 +1892,18 @@ static int rmem_swiotlb_device_init(struct reserved_= mem *rmem, kfree(mem); return -ENOMEM; } + /* + * if platform supports memory encryption, + * restricted mem pool is decrypted by default + */ + if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) { + mem->decrypted =3D true; + set_memory_decrypted((unsigned long)phys_to_virt(rmem->base), + rmem->size >> PAGE_SHIFT); + } else { + mem->decrypted =3D false; + } =20 - set_memory_decrypted((unsigned long)phys_to_virt(rmem->base), - rmem->size >> PAGE_SHIFT); swiotlb_init_io_tlb_pool(pool, rmem->base, nslabs, false, nareas); mem->force_bounce =3D true; --=20 2.43.0 From nobody Wed Jun 17 07:20:40 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A44B134B1A3; 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charset="utf-8" Fold encrypted/decrypted pgprot selection into dma_pgprot() so callers do not need to adjust the page protection separately. Update dma_pgprot() to apply pgprot_decrypted() when DMA_ATTR_CC_SHARED is set and pgprot_encrypted() otherwise Convert the dma-direct allocation and mmap paths to pass DMA_ATTR_CC_SHARED instead of open-coding force_dma_unencrypted() handling around dma_pgprot(). Signed-off-by: Aneesh Kumar K.V (Arm) --- kernel/dma/direct.c | 8 +++----- kernel/dma/mapping.c | 16 ++++++++++++---- 2 files changed, 15 insertions(+), 9 deletions(-) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 9373b9dcfb7b..a4aa7e1df2bb 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -298,9 +298,6 @@ void *dma_direct_alloc(struct device *dev, size_t size, if (remap) { pgprot_t prot =3D dma_pgprot(dev, PAGE_KERNEL, attrs); =20 - if (force_dma_unencrypted(dev)) - prot =3D pgprot_decrypted(prot); - /* remove any dirty cache lines on the kernel alias */ arch_dma_prep_coherent(page, size); =20 @@ -603,9 +600,10 @@ int dma_direct_mmap(struct device *dev, struct vm_area= _struct *vma, unsigned long pfn =3D PHYS_PFN(dma_to_phys(dev, dma_addr)); int ret =3D -ENXIO; =20 - vma->vm_page_prot =3D dma_pgprot(dev, vma->vm_page_prot, attrs); if (force_dma_unencrypted(dev)) - vma->vm_page_prot =3D pgprot_decrypted(vma->vm_page_prot); + attrs |=3D DMA_ATTR_CC_SHARED; + + vma->vm_page_prot =3D dma_pgprot(dev, vma->vm_page_prot, attrs); =20 if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret)) return ret; diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 23ed8eb9233e..44f715f3aa2d 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -543,13 +543,21 @@ EXPORT_SYMBOL(dma_get_sgtable_attrs); */ pgprot_t dma_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs) { + pgprot_t dma_prot; + if (dev_is_dma_coherent(dev)) - return prot; + dma_prot =3D prot; #ifdef CONFIG_ARCH_HAS_DMA_WRITE_COMBINE - if (attrs & DMA_ATTR_WRITE_COMBINE) - return pgprot_writecombine(prot); + else if (attrs & DMA_ATTR_WRITE_COMBINE) + dma_prot =3D pgprot_writecombine(prot); #endif - return pgprot_dmacoherent(prot); + else + dma_prot =3D pgprot_dmacoherent(prot); + + if (attrs & DMA_ATTR_CC_SHARED) + return pgprot_decrypted(dma_prot); + else + return pgprot_encrypted(dma_prot); } #endif /* CONFIG_MMU */ =20 --=20 2.43.0 From nobody Wed Jun 17 07:20:40 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5086434A78E; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ohS2YRWY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3998C19425; Mon, 27 Apr 2026 05:55:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777269356; bh=AKZl3hyjk4W1rC0aLWScXZTr07h4gBnRtI18zLYuxp0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ohS2YRWYZOk+mbH14uaSWgTPUGXxh4Fjfd/qMnTWcNvHdBrHlyGaAClhxAXqBr3ho kBT5YATwCKY3M9l8zfY0u4d17QGd3uRYkdGH+bYcDT27RiPO1jMn/RFYoG489rIX8G DfVVm/K1zoUiJOsskdlWJhSd96YUVQRud+2PQNxAf4zcqEJ7RmzQIUzjq3/R3Q2sC6 k3GnTWuQdcjv+U69NslnSgtxi6lFBOQPZPQTDR85IhVYj8wKSDA5SyWI0BqlFrzzFm 4oGA30DIDFg5n1X+4bCNcom4K7MasXk8hIE8kbHWKVctuE7NYm2kblH7CznpwaOEGe l4z3EESxvloww== From: "Aneesh Kumar K.V (Arm)" To: iommu@lists.linux.dev, linux-kernel@vger.kernel.org Cc: "Aneesh Kumar K.V (Arm)" , Robin Murphy , Marek Szyprowski , Will Deacon , Marc Zyngier , Steven Price , Suzuki K Poulose , Catalin Marinas , Jiri Pirko , Jason Gunthorpe , Mostafa Saleh , Petr Tesarik , Alexey Kardashevskiy , Dan Williams , Xu Yilun Subject: [PATCH v3 6/9] dma-direct: pass attrs to dma_capable() for DMA_ATTR_CC_SHARED checks Date: Mon, 27 Apr 2026 11:25:06 +0530 Message-ID: <20260427055509.898190-7-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260427055509.898190-1-aneesh.kumar@kernel.org> References: <20260427055509.898190-1-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-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Teach dma_capable() about DMA_ATTR_CC_SHARED so the capability check can reject encrypted DMA addresses for devices that require unencrypted/shared DMA. Also propagate DMA_ATTR_CC_SHARED in swiotlb_map() when the selected SWIOTLB pool is decrypted so the capability check sees the correct DMA address attribute. Signed-off-by: Aneesh Kumar K.V (Arm) --- arch/x86/kernel/amd_gart_64.c | 30 ++++++++++++++++-------------- drivers/xen/swiotlb-xen.c | 9 ++++++--- include/linux/dma-direct.h | 9 ++++++++- kernel/dma/direct.h | 6 +++--- kernel/dma/swiotlb.c | 8 +++++--- 5 files changed, 38 insertions(+), 24 deletions(-) diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c index e8000a56732e..b5f1f031d45b 100644 --- a/arch/x86/kernel/amd_gart_64.c +++ b/arch/x86/kernel/amd_gart_64.c @@ -180,22 +180,23 @@ static void iommu_full(struct device *dev, size_t siz= e, int dir) } =20 static inline int -need_iommu(struct device *dev, unsigned long addr, size_t size) +need_iommu(struct device *dev, unsigned long addr, size_t size, unsigned l= ong attrs) { - return force_iommu || !dma_capable(dev, addr, size, true); + return force_iommu || !dma_capable(dev, addr, size, true, attrs); } =20 static inline int -nonforced_iommu(struct device *dev, unsigned long addr, size_t size) +nonforced_iommu(struct device *dev, unsigned long addr, size_t size, + unsigned long attrs) { - return !dma_capable(dev, addr, size, true); + return !dma_capable(dev, addr, size, true, attrs); } =20 /* Map a single continuous physical area into the IOMMU. * Caller needs to check if the iommu is needed and flush. */ static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem, - size_t size, int dir, unsigned long align_mask) + size_t size, int dir, unsigned long align_mask, unsigned long attrs) { unsigned long npages =3D iommu_num_pages(phys_mem, size, PAGE_SIZE); unsigned long iommu_page; @@ -206,7 +207,7 @@ static dma_addr_t dma_map_area(struct device *dev, dma_= addr_t phys_mem, =20 iommu_page =3D alloc_iommu(dev, npages, align_mask); if (iommu_page =3D=3D -1) { - if (!nonforced_iommu(dev, phys_mem, size)) + if (!nonforced_iommu(dev, phys_mem, size, attrs)) return phys_mem; if (panic_on_overflow) panic("dma_map_area overflow %lu bytes\n", size); @@ -231,10 +232,10 @@ static dma_addr_t gart_map_phys(struct device *dev, p= hys_addr_t paddr, if (unlikely(attrs & DMA_ATTR_MMIO)) return DMA_MAPPING_ERROR; =20 - if (!need_iommu(dev, paddr, size)) + if (!need_iommu(dev, paddr, size, attrs)) return paddr; =20 - bus =3D dma_map_area(dev, paddr, size, dir, 0); + bus =3D dma_map_area(dev, paddr, size, dir, 0, attrs); flush_gart(); =20 return bus; @@ -289,7 +290,7 @@ static void gart_unmap_sg(struct device *dev, struct sc= atterlist *sg, int nents, =20 /* Fallback for dma_map_sg in case of overflow */ static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg, - int nents, int dir) + int nents, int dir, unsigned long attrs) { struct scatterlist *s; int i; @@ -301,8 +302,8 @@ static int dma_map_sg_nonforce(struct device *dev, stru= ct scatterlist *sg, for_each_sg(sg, s, nents, i) { unsigned long addr =3D sg_phys(s); =20 - if (nonforced_iommu(dev, addr, s->length)) { - addr =3D dma_map_area(dev, addr, s->length, dir, 0); + if (nonforced_iommu(dev, addr, s->length, attrs)) { + addr =3D dma_map_area(dev, addr, s->length, dir, 0, attrs); if (addr =3D=3D DMA_MAPPING_ERROR) { if (i > 0) gart_unmap_sg(dev, sg, i, dir, 0); @@ -401,7 +402,7 @@ static int gart_map_sg(struct device *dev, struct scatt= erlist *sg, int nents, s->dma_address =3D addr; BUG_ON(s->length =3D=3D 0); =20 - nextneed =3D need_iommu(dev, addr, s->length); + nextneed =3D need_iommu(dev, addr, s->length, attrs); =20 /* Handle the previous not yet processed entries */ if (i > start) { @@ -449,7 +450,7 @@ static int gart_map_sg(struct device *dev, struct scatt= erlist *sg, int nents, =20 /* When it was forced or merged try again in a dumb way */ if (force_iommu || iommu_merge) { - out =3D dma_map_sg_nonforce(dev, sg, nents, dir); + out =3D dma_map_sg_nonforce(dev, sg, nents, dir, attrs); if (out > 0) return out; } @@ -473,7 +474,8 @@ gart_alloc_coherent(struct device *dev, size_t size, dm= a_addr_t *dma_addr, return vaddr; =20 *dma_addr =3D dma_map_area(dev, virt_to_phys(vaddr), size, - DMA_BIDIRECTIONAL, (1UL << get_order(size)) - 1); + DMA_BIDIRECTIONAL, + (1UL << get_order(size)) - 1, attrs); flush_gart(); if (unlikely(*dma_addr =3D=3D DMA_MAPPING_ERROR)) goto out_free; diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index 2cbf2b588f5b..7584c6f42141 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -212,7 +212,7 @@ static dma_addr_t xen_swiotlb_map_phys(struct device *d= ev, phys_addr_t phys, BUG_ON(dir =3D=3D DMA_NONE); =20 if (attrs & DMA_ATTR_MMIO) { - if (unlikely(!dma_capable(dev, phys, size, false))) { + if (unlikely(!dma_capable(dev, phys, size, false, attrs))) { dev_err_once( dev, "DMA addr %pa+%zu overflow (mask %llx, bus limit %llx).\n", @@ -231,7 +231,7 @@ static dma_addr_t xen_swiotlb_map_phys(struct device *d= ev, phys_addr_t phys, * we can safely return the device addr and not worry about bounce * buffering it. */ - if (dma_capable(dev, dev_addr, size, true) && + if (dma_capable(dev, dev_addr, size, true, attrs) && !dma_kmalloc_needs_bounce(dev, size, dir) && !range_straddles_page_boundary(phys, size) && !xen_arch_need_swiotlb(dev, phys, dev_addr) && @@ -250,10 +250,13 @@ static dma_addr_t xen_swiotlb_map_phys(struct device = *dev, phys_addr_t phys, phys =3D map; dev_addr =3D xen_phys_to_dma(dev, map); =20 + if (dev->dma_io_tlb_mem->decrypted) + attrs |=3D DMA_ATTR_CC_SHARED; + /* * Ensure that the address returned is DMA'ble */ - if (unlikely(!dma_capable(dev, dev_addr, size, true))) { + if (unlikely(!dma_capable(dev, dev_addr, size, true, attrs))) { __swiotlb_tbl_unmap_single(dev, map, size, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC, swiotlb_find_pool(dev, map)); diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h index 94fad4e7c11e..1281d91050a4 100644 --- a/include/linux/dma-direct.h +++ b/include/linux/dma-direct.h @@ -135,12 +135,19 @@ static inline bool force_dma_unencrypted(struct devic= e *dev) #endif /* CONFIG_ARCH_HAS_FORCE_DMA_UNENCRYPTED */ =20 static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t= size, - bool is_ram) + bool is_ram, unsigned long attrs) { dma_addr_t end =3D addr + size - 1; =20 if (addr =3D=3D DMA_MAPPING_ERROR) return false; + /* + * if phys addr attribute is encrypted but the + * device is forcing an encrypted dma addr + */ + if (!(attrs & DMA_ATTR_CC_SHARED) && force_dma_unencrypted(dev)) + return false; + if (is_ram && !IS_ENABLED(CONFIG_ARCH_DMA_ADDR_T_64BIT) && min(addr, end) < phys_to_dma(dev, PFN_PHYS(min_low_pfn))) return false; diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h index 7140c208c123..e05dc7649366 100644 --- a/kernel/dma/direct.h +++ b/kernel/dma/direct.h @@ -101,15 +101,15 @@ static inline dma_addr_t dma_direct_map_phys(struct d= evice *dev, =20 if (attrs & DMA_ATTR_MMIO) { dma_addr =3D phys; - if (unlikely(!dma_capable(dev, dma_addr, size, false))) + if (unlikely(!dma_capable(dev, dma_addr, size, false, attrs))) goto err_overflow; } else if (attrs & DMA_ATTR_CC_SHARED) { dma_addr =3D phys_to_dma_unencrypted(dev, phys); - if (unlikely(!dma_capable(dev, dma_addr, size, false))) + if (unlikely(!dma_capable(dev, dma_addr, size, false, attrs))) goto err_overflow; } else { dma_addr =3D phys_to_dma(dev, phys); - if (unlikely(!dma_capable(dev, dma_addr, size, true)) || + if (unlikely(!dma_capable(dev, dma_addr, size, true, attrs)) || dma_kmalloc_needs_bounce(dev, size, dir)) { if (is_swiotlb_active(dev) && !(attrs & DMA_ATTR_REQUIRE_COHERENT)) diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index dad351988daf..0d3ae9a0130a 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -1640,12 +1640,14 @@ dma_addr_t swiotlb_map(struct device *dev, phys_add= r_t paddr, size_t size, /* * Use the allocated io_tlb_mem encryption type to determine dma addr. */ - if (dev->dma_io_tlb_mem->decrypted) + if (dev->dma_io_tlb_mem->decrypted) { dma_addr =3D phys_to_dma_unencrypted(dev, swiotlb_addr); - else + attrs |=3D DMA_ATTR_CC_SHARED; + } else { dma_addr =3D phys_to_dma_encrypted(dev, swiotlb_addr); + } =20 - if (unlikely(!dma_capable(dev, dma_addr, size, true))) { + if (unlikely(!dma_capable(dev, dma_addr, size, true, attrs))) { __swiotlb_tbl_unmap_single(dev, swiotlb_addr, size, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC, swiotlb_find_pool(dev, swiotlb_addr)); --=20 2.43.0 From nobody Wed Jun 17 07:20:40 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D5ABE34A78E; Mon, 27 Apr 2026 05:56:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777269362; cv=none; b=UnfOg2P0J8fozoriAqVfc5j9HSdDhUwe2eiBhYNE/SwH+GfA8QZiVmqBEUbzk9nhS2OaXVYn9isC7NZ9S2dfsl7QeCeDcK04Rrzs06nC+rhNm4FRbMYRWaHCbzozfvlXgAMtVa/fwT1iG0wncbNfJmN6g3a89g3JZ1TItWk5RMg= ARC-Message-Signature: i=1; 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b=ogn9yO/uhMSezYS7gKoB+sg2gd24X8EySsDh16adgVX2de23DkdDnFhEXDukXQYUx OMoYjXjr2enJxtaYflfAbviarbcs3ez3LMRUvQn+2IUQ/doMgrTsPHPuqmhE9nwGY8 ZP/cuPInKKCB54NDiVo0ROUpdy7cnGpoZqwwn5JaV2LUgOd2EA4xs4pgWNrU1gHnWQ cAPi/92x+rBc7cjvlPdLj2HhcDlCJDagkY3/+VrG5x9j0RPncPWMfkolaicWHLINOF CHpPRwoy9uCb0TgUCRlCcVuxRiBNpHdE1miDvWMWshqmrd1rBfGE5dkWSjF1h48kil LzPTyal0wCFVQ== From: "Aneesh Kumar K.V (Arm)" To: iommu@lists.linux.dev, linux-kernel@vger.kernel.org Cc: "Aneesh Kumar K.V (Arm)" , Robin Murphy , Marek Szyprowski , Will Deacon , Marc Zyngier , Steven Price , Suzuki K Poulose , Catalin Marinas , Jiri Pirko , Jason Gunthorpe , Mostafa Saleh , Petr Tesarik , Alexey Kardashevskiy , Dan Williams , Xu Yilun Subject: [PATCH v3 7/9] dma-direct: make dma_direct_map_phys() honor DMA_ATTR_CC_SHARED Date: Mon, 27 Apr 2026 11:25:07 +0530 Message-ID: <20260427055509.898190-8-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260427055509.898190-1-aneesh.kumar@kernel.org> References: <20260427055509.898190-1-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-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Teach dma_direct_map_phys() to select the DMA address encoding based on DMA_ATTR_CC_SHARED. Use phys_to_dma_unencrypted() for decrypted mappings and phys_to_dma_encrypted() otherwise. If a device requires unencrypted DMA but the source physical address is still encrypted, force the mapping through swiotlb so the DMA address and backing memory attributes remain consistent. Update the arm64 and x86 CC-guest setup to not use swiotlb force option Signed-off-by: Aneesh Kumar K.V (Arm) --- arch/arm64/mm/init.c | 4 +--- arch/x86/kernel/pci-dma.c | 4 +--- kernel/dma/direct.c | 4 +++- kernel/dma/direct.h | 30 +++++++++++++----------------- 4 files changed, 18 insertions(+), 24 deletions(-) diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 97987f850a33..acf67c7064db 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -338,10 +338,8 @@ void __init arch_mm_preinit(void) unsigned int flags =3D SWIOTLB_VERBOSE; bool swiotlb =3D max_pfn > PFN_DOWN(arm64_dma_phys_limit); =20 - if (is_realm_world()) { + if (is_realm_world()) swiotlb =3D true; - flags |=3D SWIOTLB_FORCE; - } =20 if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && !swiotlb) { /* diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index 6267363e0189..75cf8f6ae8cd 100644 --- a/arch/x86/kernel/pci-dma.c +++ b/arch/x86/kernel/pci-dma.c @@ -59,10 +59,8 @@ static void __init pci_swiotlb_detect(void) * bounce buffers as the hypervisor can't access arbitrary VM memory * that is not explicitly shared with it. */ - if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) { + if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) x86_swiotlb_enable =3D true; - x86_swiotlb_flags |=3D SWIOTLB_FORCE; - } } #else static inline void __init pci_swiotlb_detect(void) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index a4aa7e1df2bb..7d51dd93513d 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -691,8 +691,10 @@ size_t dma_direct_max_mapping_size(struct device *dev) { /* If SWIOTLB is active, use its maximum mapping size */ if (is_swiotlb_active(dev) && - (dma_addressing_limited(dev) || is_swiotlb_force_bounce(dev))) + (dma_addressing_limited(dev) || is_swiotlb_force_bounce(dev) || + force_dma_unencrypted(dev))) return swiotlb_max_mapping_size(dev); + return SIZE_MAX; } =20 diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h index e05dc7649366..af035dc935ab 100644 --- a/kernel/dma/direct.h +++ b/kernel/dma/direct.h @@ -89,36 +89,32 @@ static inline dma_addr_t dma_direct_map_phys(struct dev= ice *dev, dma_addr_t dma_addr; =20 if (is_swiotlb_force_bounce(dev)) { - if (!(attrs & DMA_ATTR_CC_SHARED)) { - if (attrs & (DMA_ATTR_MMIO | DMA_ATTR_REQUIRE_COHERENT)) - return DMA_MAPPING_ERROR; + if (attrs & (DMA_ATTR_MMIO | DMA_ATTR_REQUIRE_COHERENT)) + return DMA_MAPPING_ERROR; =20 - return swiotlb_map(dev, phys, size, dir, attrs); - } - } else if (attrs & DMA_ATTR_CC_SHARED) { - return DMA_MAPPING_ERROR; + return swiotlb_map(dev, phys, size, dir, attrs); } =20 if (attrs & DMA_ATTR_MMIO) { dma_addr =3D phys; if (unlikely(!dma_capable(dev, dma_addr, size, false, attrs))) goto err_overflow; + goto dma_mapped; } else if (attrs & DMA_ATTR_CC_SHARED) { dma_addr =3D phys_to_dma_unencrypted(dev, phys); - if (unlikely(!dma_capable(dev, dma_addr, size, false, attrs))) - goto err_overflow; } else { - dma_addr =3D phys_to_dma(dev, phys); - if (unlikely(!dma_capable(dev, dma_addr, size, true, attrs)) || - dma_kmalloc_needs_bounce(dev, size, dir)) { - if (is_swiotlb_active(dev) && - !(attrs & DMA_ATTR_REQUIRE_COHERENT)) - return swiotlb_map(dev, phys, size, dir, attrs); + dma_addr =3D phys_to_dma_encrypted(dev, phys); + } =20 - goto err_overflow; - } + if (unlikely(!dma_capable(dev, dma_addr, size, true, attrs)) || + dma_kmalloc_needs_bounce(dev, size, dir)) { + if (is_swiotlb_active(dev) && + !(attrs & DMA_ATTR_REQUIRE_COHERENT)) + return swiotlb_map(dev, phys, size, dir, attrs); + goto err_overflow; } =20 +dma_mapped: if (!dev_is_dma_coherent(dev) && !(attrs & (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_MMIO))) { arch_sync_dma_for_device(phys, size, dir); --=20 2.43.0 From nobody Wed Jun 17 07:20:40 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3E33D34A78E; Mon, 27 Apr 2026 05:56:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777269368; cv=none; b=i3RmZNVqs0INQALEZ5+mqA2sE+bjbGRKraAOj4t7VkXxbZjN+MhAGHa0oHeY45XiHdBD3Q2BkINvdFqDoELTmMwshsmV1iN4TnFFKEJvjoX8fDEgheM9YV+JzW+8CIXwH8n6+YbpCdIFOjQhN4yYHQfitqssj3QCJseJIXu+6Rk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777269368; c=relaxed/simple; bh=xibEEWJCVBE55hyDt+ak85NFqZSAoVj9pQeBEuJT7FY=; 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charset="utf-8" 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. Fix dma_direct_alloc() and dma_direct_free() to apply set_memory_*() to the linear-map alias of the backing pages instead of the remapped CPU address. Also disallow highmem pages for DMA_ATTR_CC_SHARED, because highmem buffers do not provide a usable linear-map address. Fixes: f3c962226dbe ("dma-direct: clean up the remapping checks in dma_dire= ct_alloc") Signed-off-by: Aneesh Kumar K.V (Arm) --- kernel/dma/direct.c | 30 +++++++++++++++++++++++++++--- 1 file changed, 27 insertions(+), 3 deletions(-) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 7d51dd93513d..f874be2d85c2 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -204,6 +204,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, { bool remap =3D false, set_uncached =3D false; bool mark_mem_decrypt =3D false; + bool allow_highmem =3D true; struct page *page; void *ret; =20 @@ -222,6 +223,15 @@ void *dma_direct_alloc(struct device *dev, size_t size, mark_mem_decrypt =3D true; } =20 + if (attrs & DMA_ATTR_CC_SHARED) + /* + * Unencrypted/shared DMA requires a linear-mapped buffer + * address to look up the PFN and set architecture-required PFN + * attributes. This is not possible with HighMem. Avoid HighMem + * allocation. + */ + allow_highmem =3D false; + size =3D PAGE_ALIGN(size); if (attrs & DMA_ATTR_NO_WARN) gfp |=3D __GFP_NOWARN; @@ -280,7 +290,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, } =20 /* we always manually zero the memory once we are done */ - page =3D __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, true); + page =3D __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, allow_hig= hmem); if (!page) return NULL; =20 @@ -308,7 +318,13 @@ void *dma_direct_alloc(struct device *dev, size_t size, goto out_free_pages; } else { ret =3D page_address(page); - if (mark_mem_decrypt && dma_set_decrypted(dev, ret, size)) + } + + if (mark_mem_decrypt) { + void *lm_addr; + + lm_addr =3D page_address(page); + if (set_memory_decrypted((unsigned long)lm_addr, PFN_UP(size))) goto out_leak_pages; } =20 @@ -384,8 +400,16 @@ void dma_direct_free(struct device *dev, size_t size, } else { if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_CLEAR_UNCACHED)) arch_dma_clear_uncached(cpu_addr, size); - if (mark_mem_encrypted && dma_set_encrypted(dev, cpu_addr, size)) + } + + if (mark_mem_encrypted) { + void *lm_addr; + + lm_addr =3D phys_to_virt(dma_to_phys(dev, dma_addr)); + if (set_memory_encrypted((unsigned long)lm_addr, PFN_UP(size))) { + pr_warn_ratelimited("leaking DMA memory that can't be re-encrypted\n"); return; + } } =20 __dma_direct_free_pages(dev, dma_direct_to_page(dev, dma_addr), size); --=20 2.43.0 From nobody Wed Jun 17 07:20:40 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0FA2B36897F; Mon, 27 Apr 2026 05:56:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777269374; cv=none; b=qHUHttfHijzrNdj3qfU6JUDgGD7uiaTfBFBM1Bph7ucst2J1PI1JzYnsQVuVzxIDyQ6XED4dvTwshW5ef6cAVicOxVh8ocNcKRu9wU9vR9pNe9VLCTXqAQqVhxUHYoVTUYcZnJNaNe7ibx1Itpufw/HY5iJtY9j8TI2RBFMApak= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777269374; c=relaxed/simple; bh=bFwWw9ornwOfEMIFvLXF0QGVNCkgM8YE0JfxZ/KW67Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UQ8cMdr4mpK0jwKKJQHPVsF6plBTRMcpKDeG/F2p6ymm7+9EeVen4xLBjvEToOcm0KkL/0BgeyDLvS6CKMOaHtIrn8OtxtcFI81mu7pa2atytPkM0d3j5RtVztQXs4WJ5DjNV2CuSHNF0NdkCqOQz0KURtxcbAgc5pU4Q3xbhr4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ytlds4is; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ytlds4is" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BDCCEC2BCB4; Mon, 27 Apr 2026 05:56:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777269373; bh=bFwWw9ornwOfEMIFvLXF0QGVNCkgM8YE0JfxZ/KW67Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ytlds4isRPm11He1sxPy8w+5lT/dqMr4S4YeTl9RAyBzAWszDBX/VnBlsY4AUt4AL r8Rg3bs0stHe1qX7RoSZrtxU47j4Llsmf/+FW1ZxpI6zP5XsNIb6q/13SZ6QtB4Z9N fgGtMHJ5b6bkNVZDiSbhczLmc0ZWrltM6GAHVwCptkFsi1vLscd3NlGTB4YzDAM9+t uAFARLw6NU2B616m6k91PRiREI29VvbwS73VEChpR8Zb5VdUuRGwNmeTkLA65O0ece NTWE/9a6WYkPcb8P3rQozOvEHBXDY3HCcYo8LNvGHhfgeY0oaGhF/vSamN9aRmT2Sj 4YjOdkyNbj6Fg== From: "Aneesh Kumar K.V (Arm)" To: iommu@lists.linux.dev, linux-kernel@vger.kernel.org Cc: "Aneesh Kumar K.V (Arm)" , Robin Murphy , Marek Szyprowski , Will Deacon , Marc Zyngier , Steven Price , Suzuki K Poulose , Catalin Marinas , Jiri Pirko , Jason Gunthorpe , Mostafa Saleh , Petr Tesarik , Alexey Kardashevskiy , Dan Williams , Xu Yilun Subject: [PATCH v3 9/9] dma-direct: select DMA address encoding from DMA_ATTR_CC_SHARED Date: Mon, 27 Apr 2026 11:25:09 +0530 Message-ID: <20260427055509.898190-10-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260427055509.898190-1-aneesh.kumar@kernel.org> References: <20260427055509.898190-1-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-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Make the dma-direct helpers derive the DMA address encoding from DMA_ATTR_CC_SHARED instead of implicitly relying on force_dma_unencrypted() inside phys_to_dma_direct() Pass an explicit unencrypted/decrypted state into phys_to_dma_direct(), make the alloc paths return DMA addresses that match the requested buffer encryption state. Also only call dma_set_decrypted() DMA_ATTR_CC_SHARED is actually set. Signed-off-by: Aneesh Kumar K.V (Arm) --- kernel/dma/direct.c | 48 ++++++++++++++++++++++++++++----------------- 1 file changed, 30 insertions(+), 18 deletions(-) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index f874be2d85c2..cafa6b5ed1c6 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -24,11 +24,11 @@ u64 zone_dma_limit __ro_after_init =3D DMA_BIT_MASK(24); =20 static inline dma_addr_t phys_to_dma_direct(struct device *dev, - phys_addr_t phys) + phys_addr_t phys, bool unencrypted) { - if (force_dma_unencrypted(dev)) + if (unencrypted) return phys_to_dma_unencrypted(dev, phys); - return phys_to_dma(dev, phys); + return phys_to_dma_encrypted(dev, phys); } =20 static inline struct page *dma_direct_to_page(struct device *dev, @@ -39,8 +39,9 @@ static inline struct page *dma_direct_to_page(struct devi= ce *dev, =20 u64 dma_direct_get_required_mask(struct device *dev) { + bool require_decrypted =3D force_dma_unencrypted(dev); phys_addr_t phys =3D (phys_addr_t)(max_pfn - 1) << PAGE_SHIFT; - u64 max_dma =3D phys_to_dma_direct(dev, phys); + u64 max_dma =3D phys_to_dma_direct(dev, phys, require_decrypted); =20 return (1ULL << (fls64(max_dma) - 1)) * 2 - 1; } @@ -69,7 +70,8 @@ static gfp_t dma_direct_optimal_gfp_mask(struct device *d= ev, u64 *phys_limit) =20 bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size) { - dma_addr_t dma_addr =3D phys_to_dma_direct(dev, phys); + bool require_decrypted =3D force_dma_unencrypted(dev); + dma_addr_t dma_addr =3D phys_to_dma_direct(dev, phys, require_decrypted); =20 if (dma_addr =3D=3D DMA_MAPPING_ERROR) return false; @@ -79,17 +81,18 @@ bool dma_coherent_ok(struct device *dev, phys_addr_t ph= ys, size_t size) =20 static int dma_set_decrypted(struct device *dev, void *vaddr, size_t size) { - if (!force_dma_unencrypted(dev)) - return 0; - return set_memory_decrypted((unsigned long)vaddr, PFN_UP(size)); + int ret; + + ret =3D set_memory_decrypted((unsigned long)vaddr, PFN_UP(size)); + if (ret) + pr_warn_ratelimited("leaking DMA memory that can't be decrypted\n"); + return ret; } =20 static int dma_set_encrypted(struct device *dev, void *vaddr, size_t size) { int ret; =20 - if (!force_dma_unencrypted(dev)) - return 0; ret =3D set_memory_encrypted((unsigned long)vaddr, PFN_UP(size)); if (ret) pr_warn_ratelimited("leaking DMA memory that can't be re-encrypted\n"); @@ -177,7 +180,8 @@ static void *dma_direct_alloc_from_pool(struct device *= dev, size_t size, dma_coherent_ok); if (!page) return NULL; - *dma_handle =3D phys_to_dma_direct(dev, page_to_phys(page)); + *dma_handle =3D phys_to_dma_direct(dev, page_to_phys(page), + !!(attrs & DMA_ATTR_CC_SHARED)); return ret; } =20 @@ -193,9 +197,11 @@ static void *dma_direct_alloc_no_mapping(struct device= *dev, size_t size, /* remove any dirty cache lines on the kernel alias */ if (!PageHighMem(page)) arch_dma_prep_coherent(page, size); - - /* return the page pointer as the opaque cookie */ - *dma_handle =3D phys_to_dma_direct(dev, page_to_phys(page)); + /* + * return the page pointer as the opaque cookie. + * Never used for unencrypted allocation + */ + *dma_handle =3D phys_to_dma_encrypted(dev, page_to_phys(page)); return page; } =20 @@ -337,7 +343,8 @@ void *dma_direct_alloc(struct device *dev, size_t size, goto out_encrypt_pages; } =20 - *dma_handle =3D phys_to_dma_direct(dev, page_to_phys(page)); + *dma_handle =3D phys_to_dma_direct(dev, page_to_phys(page), + !!(attrs & DMA_ATTR_CC_SHARED)); return ret; =20 out_encrypt_pages: @@ -447,11 +454,12 @@ struct page *dma_direct_alloc_pages(struct device *de= v, size_t size, return NULL; =20 ret =3D page_address(page); - if (dma_set_decrypted(dev, ret, size)) + if ((attrs & DMA_ATTR_CC_SHARED) && dma_set_decrypted(dev, ret, size)) goto out_leak_pages; setup_page: memset(ret, 0, size); - *dma_handle =3D phys_to_dma_direct(dev, page_to_phys(page)); + *dma_handle =3D phys_to_dma_direct(dev, page_to_phys(page), + !!(attrs & DMA_ATTR_CC_SHARED)); return page; out_leak_pages: return NULL; @@ -461,8 +469,12 @@ void dma_direct_free_pages(struct device *dev, size_t = size, struct page *page, dma_addr_t dma_addr, enum dma_data_direction dir) { + /* + * if the device had requested for an unencrypted buffer, + * convert it to encrypted on free + */ + bool mark_mem_encrypted =3D force_dma_unencrypted(dev); void *vaddr =3D page_address(page); - bool mark_mem_encrypted =3D true; =20 /* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */ if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) && --=20 2.43.0