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 3E2C24AB1AF; Mon, 21 Sep 2026 14:50:14 +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=1790002216; cv=none; b=e/rVepVSXR5hPHom5cK7MDP9BcfjLCZBtT20qGC2wQY/PikAD1r7I5Y+TpBHntk2t5F0+g8ehlCXbllHCsUQoju3uSAfJ0g4b7JpQQ93KAL6IlWchZpvG+6vpgDHkvb3rcitrYd03sls0RHWn7OPEjf7WClUWNnCfmSyPdLCnzk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790002216; c=relaxed/simple; bh=DSsfArB10PIcNzF5fIFeyybye5zWSuucaXodfFVDKmo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Jm+x56HHnFNOYkMLXAzmFg1Q9/gO2W8T0d/Ggsg+OUIsdNHyIOHtuKuFXCfJKNqM0mDiBiMM9qQ3CwUpMNIYyG14lKAm2A8bgw0MGc1rQmxTGciM+SYlFRjLbLWlVD2m5Ddk/omeNeDaAQeXysa5z2lEq+L1x5pmH9R/qBwkKbg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ik8PkMSE; 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="ik8PkMSE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 817AE1F008A1; Mon, 21 Sep 2026 14:50:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790002214; bh=aWYdZ91y2ZIXgzfNWppX/K87BNGkPgAm/JMTyJDzEh4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ik8PkMSEyJLfZFUGTT09e/znzmIj1IQB1TBp51D5k+Yy0ho+aw3/dRdBdIpRmKYnr ZX0EP5g0NObBCy2Gjw2BuyvDeKhrqS+fY/IdnQoAEEECDsWQ3gk00OnyJEj94hJEsS jcs/OA949tuP2PX2vfy+us7YkGRG7OZKcMEHoajnenBSSE1rRr5PMTaippawTE2vpC 678DJsoB1qY8zfYxIX4yfz7lpI2H6IGYT22cB5GPSXDOBmyMgKu3O0QYqM4ivx4SfI Cld32H3UEmro8rXX+UU0djHeoYDylyNw0S8cJfuOsD6TdJzT/bK/IAFSMizS0sB+UB 4AZHXeqwquuiw== 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 , Catalin Marinas , christian.koenig@amd.com, Jason Gunthorpe , Joerg Roedel , Marc Zyngier , Marek Szyprowski , Robin Murphy , Steven Price , Sumit Semwal , Suzuki K Poulose , Thomas Gleixner , Will Deacon , dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-media@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH v7 08/13] dma-direct: Align CoCo shared DMA allocations to the shared granule size Date: Mon, 21 Sep 2026 20:18:42 +0530 Message-ID: <20260921144847.501151-9-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260921144847.501151-1-aneesh.kumar@kernel.org> References: <20260921144847.501151-1-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, pass the required alignment order through the DMA contiguous allocator, and 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. Signed-off-by: Aneesh Kumar K.V (Arm) --- kernel/dma/direct.c | 55 +++++++++++++++++++++++++++++++++++---------- 1 file changed, 43 insertions(+), 12 deletions(-) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index d968a0c81e73..d293198384c3 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 int align_order) { 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, align_order); 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 +205,8 @@ 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; + unsigned int align_order = 0; struct page *page; void *cpu_addr; @@ -285,8 +287,16 @@ 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; + align_order = get_order(layout.alignment); + } + /* 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, align_order); if (!page) return NULL; @@ -305,7 +315,7 @@ 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; } @@ -362,6 +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); /* @@ -406,6 +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 { @@ -417,10 +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) @@ -433,6 +448,8 @@ 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; + unsigned int align_order = 0; struct page *page; void *cpu_addr; @@ -452,7 +469,14 @@ 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 (attrs & __DMA_ATTR_ALLOC_CC_SHARED) { + if (cc_shared_calc_layout(size, &layout)) + return NULL; + size = layout.shared_size; + align_order = get_order(layout.alignment); + } + + page = __dma_direct_alloc_pages(dev, size, gfp, false, align_order); if (!page) return NULL; @@ -476,6 +500,7 @@ 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 @@ -492,6 +517,12 @@ 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