From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 42CCF47140F; Thu, 24 Sep 2026 10:07:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790244483; cv=none; b=X5XfKKfu8jSi0X8aZydPhTYxMHSo1pSRwRZmgn1ZOARKwkAcgofVqCfyZTZ19f9yy64BJs3Yaaxz/GeKI0xqyRkU3T3eBmPcAAXAWSpC+RoAkXTtQT+SBaaMuOHrOxoSEIp3Z5Ww4eKGB8cOL/H14tyTW4Pt58iKHogIsmYMSXc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790244483; c=relaxed/simple; bh=wmWWe2U/E72QDG+2xlM7yuHMbAAZEIXrUVkI/yKGFq8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pVoMhBh1blRazxXbKvIwOLqt/GzC8p8M75eREa5Er+EMJNnkA1AmoWQlwjn/TL92EFvKzmG9JgD1NZPhF0LV7hDMiCMT5I96YoZF2gysfteIwda3JNEi26Hyaqe+V/gxivp/dO0XrLQ3FuSE8sr9yNvMr+n3uoFOm5JyCYNkLp0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hNxRqbRX; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hNxRqbRX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F19E81F00893; Thu, 24 Sep 2026 10:07:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790244468; bh=GJ0WVrMy94SvEspEtHLkpWdnYwmIG1CQN164cHPWINA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hNxRqbRXCBgOSlhg7QIsbDMl/whpfkl0ji4BaBHpuxUxIl14Vx/ArJ7tNq0y1ndJF y9K5awNXnNh1KYw2+eWvCuc/PssjIkDyqaZWu4L877wC/jKUjqJ1vtwayk98/dUizt 3iMzqyg/Nr0Yi1NyIP5FNWknNNPLaEoaD4qY7DkTirbj7N+UPwQVnWdkefhMMilbyX qzg/oa0RKZLl0sPbOB816fgurHhifb89rdCCSvVAa8jEUMDiGPzlFZ1/Pr/Yn3kxKf +J7YuR28nAYg+9+WmWPWuGTOd4kD+JTXcvMadE+gkobA8U2AGqOoDVzjqNn7LAMkRu O52L6EXUAbO6Q== From: "Aneesh Kumar K.V (Arm)" To: linux-coco@lists.linux.dev, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, iommu@lists.linux.dev Cc: "Aneesh Kumar K.V (Arm)" , Andrew Morton , Baoquan He , Mike Rapoport , Pasha Tatashin , Pratyush Yadav , Catalin Marinas , =?UTF-8?q?Christian=20K=C3=B6nig?= , Jason Gunthorpe , Joerg Roedel , Marc Zyngier , Marek Szyprowski , Robin Murphy , Steven Price , Sumit Semwal , Suzuki K Poulose , Thomas Gleixner , Will Deacon , Russell King , Benjamin Gaignard , Brian Starkey , John Stultz , Mark Rutland , Radu Rendec , "T.J. Mercier" , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Ritesh Harjani , Shrikanth Hegde , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Kiryl Shutsemau , Rick Edgecombe , "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Paolo Bonzini , Vitaly Kuznetsov , Andy Lutomirski , Peter Zijlstra , dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-media@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH v8 07/14] dma-direct: Align CoCo shared DMA allocations to the shared granule size Date: Thu, 24 Sep 2026 15:35:22 +0530 Message-ID: <20260924100529.1398790-8-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260924100529.1398790-1-aneesh.kumar@kernel.org> References: <20260924100529.1398790-1-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: 8bit Use the common CoCo shared-memory geometry helpers for allocations backed directly by CMA or the page allocator. Round the backing allocation to a whole shared granule and pass the resolved shared-allocation attribute through the DMA contiguous allocator so it can enforce the mandatory alignment. Transition the complete range through the common shared/private helpers. Recompute the layout before freeing ordinary direct allocations so the transition back to private memory and dma_free_contiguous() cover exactly the range acquired by the allocation path. If restoring private state fails, retain the existing fail-safe behavior and leak the pages rather than returning potentially shared memory to the allocator. This also applies the same rules to dma_direct_alloc_pages(), covering callers which require a struct page result rather than a CPU virtual address. Cc: Marek Szyprowski Cc: Robin Murphy Assisted-by: Codex:gpt-5 Signed-off-by: Aneesh Kumar K.V (Arm) --- kernel/dma/direct.c | 51 ++++++++++++++++++++++++++++++++++----------- 1 file changed, 39 insertions(+), 12 deletions(-) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index cb14419f8a09..09a8a842fc6f 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -11,10 +11,10 @@ #include #include #include -#include #include #include #include +#include #include "direct.h" @@ -85,7 +85,7 @@ static int dma_set_decrypted(struct device *dev, void *vaddr, size_t size) { int ret; - ret = set_memory_decrypted((unsigned long)vaddr, PFN_UP(size)); + ret = cc_make_shared(vaddr, size); if (ret) pr_warn_ratelimited("leaking DMA memory that can't be decrypted\n"); return ret; @@ -95,7 +95,7 @@ static int dma_set_encrypted(struct device *dev, void *vaddr, size_t size) { int ret; - ret = set_memory_encrypted((unsigned long)vaddr, PFN_UP(size)); + ret = cc_make_private(vaddr, size); if (ret) pr_warn_ratelimited("leaking DMA memory that can't be re-encrypted\n"); return ret; @@ -115,7 +115,7 @@ static struct page *dma_direct_alloc_swiotlb(struct device *dev, size_t size, } static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size, - gfp_t gfp, bool allow_highmem) + gfp_t gfp, bool allow_highmem, unsigned long attrs) { int node = dev_to_node(dev); struct page *page; @@ -124,7 +124,7 @@ static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size, WARN_ON_ONCE(!PAGE_ALIGNED(size)); gfp |= dma_direct_optimal_gfp_mask(dev, &phys_limit); - page = dma_alloc_contiguous(dev, size, gfp, 0); + page = dma_alloc_contiguous(dev, size, gfp, attrs); if (page) { if (dma_coherent_ok(dev, page_to_phys(page), size) && (allow_highmem || !PageHighMem(page))) @@ -184,7 +184,7 @@ static void *dma_direct_alloc_no_mapping(struct device *dev, size_t size, { struct page *page; - page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, true); + page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, true, 0); if (!page) return NULL; @@ -205,6 +205,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, bool remap = false, set_uncached = false; bool mark_mem_decrypt = false; bool allow_highmem = true; + struct cc_shared_layout layout; struct page *page; void *cpu_addr; @@ -285,8 +286,15 @@ void *dma_direct_alloc(struct device *dev, size_t size, return NULL; } + if (mark_mem_decrypt) { + if (cc_shared_calc_layout(size, &layout)) + return NULL; + size = layout.shared_size; + } + /* we always manually zero the memory once we are done */ - page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, allow_highmem); + page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, + allow_highmem, attrs); if (!page) return NULL; @@ -305,7 +313,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, void *lm_addr; lm_addr = page_address(page); - if (set_memory_decrypted((unsigned long)lm_addr, PFN_UP(size))) + if (dma_set_decrypted(dev, lm_addr, size)) goto out_leak_pages; } @@ -364,6 +372,7 @@ void dma_direct_free(struct device *dev, size_t size, phys_addr_t phys; bool mark_mem_encrypted = false; struct io_tlb_pool *swiotlb_pool; + struct cc_shared_layout layout; unsigned int page_order = get_order(size); /* @@ -408,6 +417,12 @@ void dma_direct_free(struct device *dev, size_t size, /* Swiotlb doesn't need a page attribute update on free */ mark_mem_encrypted = false; + if (mark_mem_encrypted) { + if (WARN_ON_ONCE(cc_shared_calc_layout(size, &layout))) + return; + size = layout.shared_size; + } + if (is_vmalloc_addr(cpu_addr)) { vunmap(cpu_addr); } else { @@ -419,10 +434,8 @@ void dma_direct_free(struct device *dev, size_t size, void *lm_addr; lm_addr = phys_to_virt(phys); - if (set_memory_encrypted((unsigned long)lm_addr, PFN_UP(size))) { - pr_warn_ratelimited("leaking DMA memory that can't be re-encrypted\n"); + if (dma_set_encrypted(dev, lm_addr, size)) return; - } } if (swiotlb_pool) @@ -435,6 +448,7 @@ 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 = 0; + struct cc_shared_layout layout; struct page *page; void *cpu_addr; bool mark_mem_decrypt; @@ -458,7 +472,13 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size, goto setup_page; } - page = __dma_direct_alloc_pages(dev, size, gfp, false); + if (mark_mem_decrypt) { + if (cc_shared_calc_layout(size, &layout)) + return NULL; + size = layout.shared_size; + } + + page = __dma_direct_alloc_pages(dev, size, gfp, false, attrs); if (!page) return NULL; @@ -484,6 +504,7 @@ void dma_direct_free_pages(struct device *dev, size_t size, phys_addr_t phys; void *vaddr = page_address(page); struct io_tlb_pool *swiotlb_pool; + struct cc_shared_layout layout; /* * if the device had requested for an unencrypted buffer, * convert it to encrypted on free @@ -500,6 +521,12 @@ void dma_direct_free_pages(struct device *dev, size_t size, if (swiotlb_pool) mark_mem_encrypted = false; + if (mark_mem_encrypted) { + if (WARN_ON_ONCE(cc_shared_calc_layout(size, &layout))) + return; + size = layout.shared_size; + } + if (mark_mem_encrypted && dma_set_encrypted(dev, vaddr, size)) return; -- 2.43.0