From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 662E9C7115C for ; Wed, 25 Jun 2025 06:33:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=+4JnsBDmTVO4IHPEs7SpJJ+ekomh2XoOEGIyJQ8TByE=; b=oyS3uwjHM2KUS0 Fp8cU3lBbFGx3+Sx6JMSCz3jA3mk2T2OAdT3/EYUCfkMRKuHrGv0G+sMrt8kC5gl2z35f6g34qpmW xUCwCHLQFATeplsI6i6F9mRlX1JT7F94g0G8VSDfuG6hqFbW9BE1UmTGIqjUuoVTPEFsgMK/Xxw5B VjNBocrpEhgD8oAkAk9nYFpkn6iu5b7epj8JAPuL0cMfl8rLzws3ZvTjpsFO89+hEIhvaT2ME8zSN Hu44JG9wofll+fVFRn/VSmndYiBTTbWfNc5PGBVYlp2Vs6JpZ9SVb+r6GRuWy8B0zwQ8EOCFouU5U 7oVlxIpmS2Adbfarqvjg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uUJhM-00000007fX1-0C4Y; Wed, 25 Jun 2025 06:33:32 +0000 Received: from nyc.source.kernel.org ([2604:1380:45d1:ec00::3]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uUJhI-00000007fWN-31tC for linux-mtd@lists.infradead.org; Wed, 25 Jun 2025 06:33:30 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 71C99A50D35; Wed, 25 Jun 2025 06:33:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D7B4DC4CEEA; Wed, 25 Jun 2025 06:33:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750833207; bh=KvBZdCVe3bjcds3toNzSaotNrJRp/h1SfSaoHVQtlow=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bgakoUfAtI3aZ6TL8fY22KKltCf5IxNhnzJ2oiyuuI/GEIHZVXnwJ10tWdkSvPitL /7bgjo9d0xQe1/8gpM9TBWDxFi/Ea0rEL81mSYagOjUKrHIXs7lqZdbBqzmHFzyv8u ZWO+dWfZgHmJ/TMTmP0277ODQYtrlhMqpajvswJ8zCCo09C9Bj7uSHR7SGVz+9SwGl KSwIFk6u+iudkaHqeTJb2dbajWY0742z1b6HWGCzoj5/myPz3cCTRLT7guhEKxa1Ue qWBczEoXOLdeLmUv9Qp8JOrF2q6gevGPPGRKDXQ/LfFR2ZmiDmtFXt9weQocqTrCp1 Hz6xQ9sygvLRQ== Date: Tue, 24 Jun 2025 23:32:52 -0700 From: Eric Biggers To: Simon Richter Cc: linux-fscrypt@vger.kernel.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, ceph-devel@vger.kernel.org Subject: Re: [PATCH] fscrypt: don't use hardware offload Crypto API drivers Message-ID: <20250625063252.GD8962@sol> References: <20250611205859.80819-1-ebiggers@kernel.org> <7f63be76-289b-4a99-b802-afd72e0512b8@hogyros.de> <20250612005914.GA546455@google.com> <20250612062521.GA1838@sol> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20250612062521.GA1838@sol> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250624_233328_886875_D290404C X-CRM114-Status: GOOD ( 21.34 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Wed, Jun 11, 2025 at 11:25:21PM -0700, Eric Biggers wrote: > On Thu, Jun 12, 2025 at 12:59:14AM +0000, Eric Biggers wrote: > > On Thu, Jun 12, 2025 at 09:21:26AM +0900, Simon Richter wrote: > > > Hi, > > > > > > On 6/12/25 05:58, Eric Biggers wrote: > > > > > > > But > > > > otherwise this style of hardware offload is basically obsolete and has > > > > been superseded by hardware-accelerated crypto instructions directly on > > > > the CPU as well as inline storage encryption (UFS/eMMC). > > > > > > For desktop, yes, but embedded still has quite a few of these, for example > > > the STM32 crypto offload engine > > By the way, I noticed you specifically mentioned STM32. I'm not sure if you > looked at the links I had in my commit message, but one of them > (https://github.com/google/fscryptctl/issues/32) was actually for the STM32 > driver being broken and returning the wrong results, which broke filename > encryption. The user fixed the issue by disabling the STM32 driver, and they > seemed okay with that. > > That doesn't sound like something useful, IMO. It sounds more like something > actively harmful to users. > > Here's another one I forgot to mention: > https://github.com/google/fscryptctl/issues/9 > > I get blamed for these issues, because it's fscrypt that breaks. Since two people were pushing the STM32 crypto engine in this thread: I measured decryption throughput on 4 KiB messages on an STM32MP157F-DK2. This is an embedded evaluation board that includes an STM32 crypto engine and has an 800 MHz Cortex-A7 processor. Cortex-A7 doesn't have AES instructions: AES-128-CBC-ESSIV: essiv(stm32-cbc-aes,sha256-arm): 3.1 MB/s essiv(cbc-aes-neonbs,sha256-arm): 15.5 MB/s AES-256-XTS: xts(stm32-ecb-aes): 3.1 MB/s xts-aes-neonbs: 11.0 MB/s Adiantum: adiantum(xchacha12-arm,aes-arm,nhpoly1305-neon): 53.1 MB/s That was the synchronous throughput. However, submitting multiple requests asynchronously (which again, fscrypt doesn't actually do) barely helps. Apparently the STM32 crypto engine has only one hardware queue. I already strongly suspected that these non-inline crypto engines aren't worth using. But I didn't realize they are quite this bad. Even with AES on a Cortex-A7 CPU that lacks AES instructions, the CPU is much faster! But of course Adiantum is even faster, as it was specifically designed for CPUs that don't have AES instructions. - Eric ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/