From mboxrd@z Thu Jan 1 00:00:00 1970 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 D464E270EDF; Fri, 17 Apr 2026 08:59:57 +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=1776416397; cv=none; b=qnqEB5rbmPRDA5Yms1Rmz3QehxZZgqusm3adSVSkB2G4dHKHOZochFvCAD1injQNqCpjDeMGQOl+tFouN/LgWlAf9+88cIrvNMG3kLbmqQbb+4nZYJgAjnlyh6dgqvaUmmoB8cOaxdh6uscwGoBTT5v4DwS50MTuHUez5v12tVI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776416397; c=relaxed/simple; bh=Im5Egu+28aJChtCEne+SeNAV/nf1ZLputmBfj4oRyVc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ny1gswm3k1QtcvDOKSocXLxDeLD40Z0afvLi7CNNWNtVW4GTdaSiKLLJ0aqnwZnmCxfxoSumqE4pDbGnlF6CGLqxQ6PejjHe++OiXnDqAuzJHeBZ/8k6ntq6gV32LiWmHKGJ6E346xPphlCKvozteZLGWNs2FRs3dHMsruk0IxU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OSqDYucR; 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="OSqDYucR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E8B1CC19425; Fri, 17 Apr 2026 08:59:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776416397; bh=Im5Egu+28aJChtCEne+SeNAV/nf1ZLputmBfj4oRyVc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OSqDYucRSBjMSaiamJTfgg6YeVGGug8B2EHSGC5n16qIja6KcVoNPvNmvLEOxhLmA QU5cUPX9k/X9m1razPAWASI0RBNrqkuXxDRVKSnu5OB2UsMA94qvhLZMWZnWGoidzl 8QexDIwI/5Yc8gkIKJ8pApveO4AB9wAxcjtqIx/f8yVn1bpVpcH4OqsEHtAnVEOCF2 Rkf29kNznpLyqKv2rx6tDJ2JFlGZfIdzGM9O4PXD9XJRcH92VpkkgAU0bfDiLQasSW 4fwHyoFSZj//Ai/urvIVEzu5gZDiK1Q3jRWnBXc9Lu6uXBSWJmGKCRejku5WL0/oWJ B0XVW+Tk5Rg6A== From: "Aneesh Kumar K.V (Arm)" To: iommu@lists.linux.dev, linux-kernel@vger.kernel.org Cc: robin.murphy@arm.com, m.szyprowski@samsung.com, will@kernel.org, maz@kernel.org, suzuki.poulose@arm.com, catalin.marinas@arm.com, jiri@resnulli.us, jgg@ziepe.ca, aneesh.kumar@kernel.org, Mostafa Saleh Subject: [RFC PATCH 3/7] dma-pool: track decrypted atomic pools and select them via attrs Date: Fri, 17 Apr 2026 14:28:56 +0530 Message-ID: <20260417085900.3062416-4-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260417085900.3062416-1-aneesh.kumar@kernel.org> References: <20260417085900.3062416-1-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 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_DECRYPTED. Update dma_free_from_pool() accordingly. Also pass DMA_ATTR_CC_DECRYPTED 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 94d514169642..ddd5dd244a86 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -1650,7 +1650,7 @@ 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 = dma_alloc_from_pool(dev, PAGE_ALIGN(size), &cpu_addr, - gfp, NULL); + gfp, attrs, NULL); else cpu_addr = 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 60b63756df82..72bc28c0390e 100644 --- a/include/linux/dma-map-ops.h +++ b/include/linux/dma-map-ops.h @@ -217,7 +217,7 @@ 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); 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); diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 3932033f4d8c..ba1c731e001d 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) } 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; gfp |= dma_direct_optimal_gfp_mask(dev, &phys_limit); - page = dma_alloc_from_pool(dev, size, &ret, gfp, dma_coherent_ok); + page = dma_alloc_from_pool(dev, size, &ret, gfp, attrs, + dma_coherent_ok); if (!page) return NULL; *dma_handle = phys_to_dma_direct(dev, page_to_phys(page)); @@ -251,7 +252,8 @@ void *dma_direct_alloc(struct device *dev, size_t size, */ if ((remap || (attrs & DMA_ATTR_CC_DECRYPTED)) && 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); if (is_swiotlb_for_alloc(dev)) { page = dma_direct_alloc_swiotlb(dev, size); @@ -387,7 +389,8 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size, attrs |= DMA_ATTR_CC_DECRYPTED; if ((attrs & DMA_ATTR_CC_DECRYPTED) && 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); if (is_swiotlb_for_alloc(dev)) { page = dma_direct_alloc_swiotlb(dev, size); diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c index 2b2fbb709242..e4dde3e769bf 100644 --- a/kernel/dma/pool.c +++ b/kernel/dma/pool.c @@ -12,12 +12,18 @@ #include #include #include +#include -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; /* Size can be defined by the coherent_pool command line */ @@ -76,7 +82,7 @@ static bool cma_in_zone(gfp_t gfp) return true; } -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_size, 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 = set_memory_decrypted((unsigned long)page_to_virt(page), + if (dma_pool->decrypted) { + ret = set_memory_decrypted((unsigned long)page_to_virt(page), 1 << order); - if (ret) - goto remove_mapping; - ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page), + if (ret) + goto remove_mapping; + } + + ret = gen_pool_add_virt(dma_pool->pool, (unsigned long)addr, page_to_phys(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; encrypt_mapping: - ret = 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 = 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; } -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); } 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); } -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_pool *dma_pool, + size_t pool_size, gfp_t gfp) { - struct gen_pool *pool; int ret; - pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE); - if (!pool) + dma_pool->pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE); + if (!dma_pool->pool) return NULL; - 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 decrypted. */ + if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) + dma_pool->decrypted = true; + else + dma_pool->decrypted = false; - ret = atomic_pool_expand(pool, pool_size, gfp); + ret = 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; } 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; } #ifdef CONFIG_ZONE_DMA32 @@ -207,21 +223,22 @@ static int __init dma_atomic_pool_init(void) /* All memory might be in the DMA zone(s) to begin with */ if (has_managed_zone(ZONE_NORMAL)) { - atomic_pool_kernel = __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 = -ENOMEM; } + if (has_managed_dma()) { - atomic_pool_dma = __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 = -ENOMEM; } + if (has_managed_dma32) { - atomic_pool_dma32 = __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 = -ENOMEM; } @@ -230,19 +247,38 @@ static int __init dma_atomic_pool_init(void) } postcore_initcall(dma_atomic_pool_init); -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 *prev, gfp_t gfp) { if (prev == 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 == atomic_pool_kernel) - return atomic_pool_dma32 ? atomic_pool_dma32 : atomic_pool_dma; - if (prev == atomic_pool_dma32) - return atomic_pool_dma; + if (prev == &atomic_pool_kernel) { + if (atomic_pool_dma32.pool) + return &atomic_pool_dma32; + return &atomic_pool_dma; + } + if (prev == &atomic_pool_dma32) + return &atomic_pool_dma; return NULL; } @@ -272,16 +308,20 @@ static struct page *__dma_alloc_from_pool(struct device *dev, size_t size, } 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 = NULL; + struct dma_gen_pool *dma_pool = NULL; struct page *page; bool pool_found = false; - while ((pool = dma_guess_pool(pool, gfp))) { + while ((dma_pool = dma_guess_pool(dma_pool, gfp))) { + + if (dma_pool->decrypted != !!(attrs & DMA_ATTR_CC_DECRYPTED)) + continue; + pool_found = true; - page = __dma_alloc_from_pool(dev, size, pool, cpu_addr, + page = __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, bool dma_free_from_pool(struct device *dev, void *start, size_t size) { - struct gen_pool *pool = NULL; + struct dma_gen_pool *dma_pool = NULL; - while ((pool = dma_guess_pool(pool, 0))) { - if (!gen_pool_has_addr(pool, (unsigned long)start, size)) + while ((dma_pool = dma_guess_pool(dma_pool, 0))) { + + if (!gen_pool_has_addr(dma_pool->pool, (unsigned long)start, size)) continue; - gen_pool_free(pool, (unsigned long)start, size); + + gen_pool_free(dma_pool->pool, (unsigned long)start, size); return true; } diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 9fd73700ddcf..2373a9f7e21a 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -623,7 +623,9 @@ static struct page *swiotlb_alloc_tlb(struct device *dev, size_t bytes, if (!IS_ENABLED(CONFIG_DMA_COHERENT_POOL)) return NULL; + /* considered decrypted by default */ return dma_alloc_from_pool(dev, bytes, &vaddr, gfp, + DMA_ATTR_CC_DECRYPTED, dma_coherent_ok); } -- 2.43.0