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 AF0D723BD02; Fri, 17 Apr 2026 09:56:20 +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=1776419780; cv=none; b=i6te/LIlyFPsioJvahDK+c4y6sWaonI03KTlGSuUutoi9x8g8+QSM8l7t6DJLz8wOMRK9LSuXFk45d9NoAGl1oFa7sV/3tdX9AAanPS9ap3mkenLNJ9NmUH6xUA8vWspifS03T2kRY8m/Cx/g6ygqDbLL3EEqcaKAmi3NdZRU9w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776419780; c=relaxed/simple; bh=59tfoMBqti+0Vm14vEl9sXO5vfXuwKWNjTQwMptc8Qs=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=XWu/R9+t05xeVES7U0HtmviijnUOuUQGs4dREFHMvPSm5g1uwCb4ENzP3b4CUDMi/ZBo7gAzVScAAg98STKVvcD9MqTU61njPSEDR0AE9EZcU3c72xH6e3n8Y+DzUXwpkqbegDbRoM8+97Edd+aX7ae3jFK3jr8n3Kwkju9w7mc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LcKWovGM; 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="LcKWovGM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 98548C19425; Fri, 17 Apr 2026 09:56:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776419780; bh=59tfoMBqti+0Vm14vEl9sXO5vfXuwKWNjTQwMptc8Qs=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=LcKWovGM1ODvjmxpvalDiphgTygEAncSvruAVkOp32BU1+9xs3vzt7oGmpuH2COTe Bqw3NoRWjiK9e3LfzfYBcGP+zBS5AgBaSywvEDXSUSO1CgngE4LpVAZXsMkbQn1G/J xxtMXomrMhyTt38pVfdNpYNjC6sir/oX6CDhgBloDwtM9d9fKPxpBW+zFGbheoYEOe aZm2f8dj7g9y1XZfrfu8SG+EcTYIl3FMypfPXY1i0oO5HodJA/TeblrL5fuDeMKmdG vv/j0V+gi38p0wBWH1iHDkdFDVMheOzm9aCTIoY1w6F7bWribM4N/CerdNkNZBJazk kqTVQHraCtEDw== X-Mailer: emacs 30.2 (via feedmail 11-beta-1 I) From: Aneesh Kumar K.V 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, Mostafa Saleh Subject: [RFC PATCH] dma-direct: select DMA address encoding from DMA_ATTR_CC_DECRYPTED In-Reply-To: <20260417085900.3062416-1-aneesh.kumar@kernel.org> References: <20260417085900.3062416-1-aneesh.kumar@kernel.org> Date: Fri, 17 Apr 2026 15:26:13 +0530 Message-ID: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain From: "Aneesh Kumar K.V (Arm)" Make the dma-direct helpers derive the DMA address encoding from DMA_ATTR_CC_DECRYPTED 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() when DMA_ATTR_CC_DECRYPTED is actually set. Signed-off-by: Aneesh Kumar K.V (Arm) --- Missed doing this conversion in the pervious set. --- kernel/dma/direct.c | 41 ++++++++++++++++++++++++----------------- 1 file changed, 24 insertions(+), 17 deletions(-) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index bb2a32896a9e..70fc9ed9ad1a 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -24,11 +24,11 @@ u64 zone_dma_limit __ro_after_init = DMA_BIT_MASK(24); 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); } static inline struct page *dma_direct_to_page(struct device *dev, @@ -39,8 +39,9 @@ static inline struct page *dma_direct_to_page(struct device *dev, u64 dma_direct_get_required_mask(struct device *dev) { + bool require_decrypted = force_dma_unencrypted(dev); phys_addr_t phys = (phys_addr_t)(max_pfn - 1) << PAGE_SHIFT; - u64 max_dma = phys_to_dma_direct(dev, phys); + u64 max_dma = phys_to_dma_direct(dev, phys, require_decrypted); return (1ULL << (fls64(max_dma) - 1)) * 2 - 1; } @@ -69,7 +70,8 @@ static gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 *phys_limit) bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size) { - dma_addr_t dma_addr = phys_to_dma_direct(dev, phys); + bool require_decrypted = force_dma_unencrypted(dev); + dma_addr_t dma_addr = phys_to_dma_direct(dev, phys, require_decrypted); if (dma_addr == DMA_MAPPING_ERROR) return false; @@ -79,8 +81,6 @@ bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size) 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)); } @@ -88,8 +88,6 @@ static int dma_set_encrypted(struct device *dev, void *vaddr, size_t size) { int ret; - if (!force_dma_unencrypted(dev)) - return 0; ret = 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 +175,8 @@ static void *dma_direct_alloc_from_pool(struct device *dev, size_t size, dma_coherent_ok); if (!page) return NULL; - *dma_handle = phys_to_dma_direct(dev, page_to_phys(page)); + *dma_handle = phys_to_dma_direct(dev, page_to_phys(page), + !!(attrs & DMA_ATTR_CC_DECRYPTED)); return ret; } @@ -193,9 +192,11 @@ 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 = phys_to_dma_direct(dev, page_to_phys(page)); + /* + * return the page pointer as the opaque cookie. + * Never used for unencrypted allocation + */ + *dma_handle = phys_to_dma_direct(dev, page_to_phys(page), false); return page; } @@ -327,7 +328,8 @@ void *dma_direct_alloc(struct device *dev, size_t size, goto out_encrypt_pages; } - *dma_handle = phys_to_dma_direct(dev, page_to_phys(page)); + *dma_handle = phys_to_dma_direct(dev, page_to_phys(page), + !!(attrs & DMA_ATTR_CC_DECRYPTED)); return ret; out_encrypt_pages: @@ -437,11 +439,12 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size, return NULL; ret = page_address(page); - if (dma_set_decrypted(dev, ret, size)) + if ((attrs & DMA_ATTR_CC_DECRYPTED) && dma_set_decrypted(dev, ret, size)) goto out_leak_pages; setup_page: memset(ret, 0, size); - *dma_handle = phys_to_dma_direct(dev, page_to_phys(page)); + *dma_handle = phys_to_dma_direct(dev, page_to_phys(page), + !!(attrs & DMA_ATTR_CC_DECRYPTED)); return page; out_leak_pages: return NULL; @@ -451,8 +454,12 @@ 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 = force_dma_unencrypted(dev); void *vaddr = page_address(page); - bool mark_mem_encrypted = true; /* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */ if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) && -- 2.43.0