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 3DBD741D10A; Wed, 22 Jul 2026 16:20:42 +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=1784737243; cv=none; b=Its2Z1rRimNuq9oQdwvwsY5aJUjylY4QjlNr9fgOg7W+KBiUdcq+UB+8ErsGg9A7rHFdW1Eb05P4d4z+FTM+uGkNcLFYDf2KI4hYDnZEu+JUwB0T6y8tGouOs1ZAfzyy24gDdrVnk4Gj7eSeSbDgM+lXvqK6rb906Hcmn/5sm1U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784737243; c=relaxed/simple; bh=ko1nD3riK0WkNrw9/nLRc62E2PQBCo3M4PL8aYTl7/0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=EzQjef/Xvxu7HUtE6YD4yJ3edJn0NW67ZtSHuMr7IUIhBFBDVvKUoA97jf/pxxi5kJSBlB9HRXpUxSZSAB8Z8z+qgoxwt/FnNGMTtsMY4SNFdRb5qM93ojTbHWQkMgZROYqAz5vnr2iHfKsa5MSzUvJxiosp+8fEa1/WVMh30O8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XFRfUPAB; 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="XFRfUPAB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 830351F000E9; Wed, 22 Jul 2026 16:20:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784737242; bh=1Exwl0AsGwf6M6S13oTNWhmNyTBsKTiqZ5UEvnNJspo=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=XFRfUPABWpzjJ7fOkBcKIqJ4BWV+1eBvjFuNRgixzas8vrIhpRievAN+vHwpRM9tG RfgbtQd3Bu08Vv4/ka0sxj+j+psYSiVNox2dCK5uXC0oJ9L0nM1Wugrpi2YutCqSSJ doFwvVXvqg4TrXdU67FEBE4Srxo8uJxwCynncGWgDm3/dcCbqqKcMm/EYDiZGB3yK+ C9PNJNsepyuoWb1EeN+6hxnUwxSL9HVeLYQ5rxr1STHBu8xDsWO1te4hVGdz9rQZyU BTKfcGrAOtxZYe3xH5y6ZHcdKjWy3P3bkSvEIke5NKhzbRYmnBHnHRRXrJklq7l99l yuquli/u/mWbw== Date: Wed, 22 Jul 2026 16:20:40 +0000 From: Eric Biggers To: Bartosz Golaszewski Cc: Demi Marie Obenour , Bartosz Golaszewski , Herbert Xu , Russell King , "David S. Miller" , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, linux-arm-msm@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v2] drivers/crypto: Mark QCE as BROKEN Message-ID: <20260722162040.GC2794619@google.com> References: <20260712-qce-broken-v2-1-b2dfff47f7f5@gmail.com> <20260721082501.6128-1-bartosz.golaszewski@oss.qualcomm.com> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Jul 22, 2026 at 01:33:51AM -0700, Bartosz Golaszewski wrote: > > Also, what can the current driver do that cannot be done better using > > software crypto? I understand that you have future plans to add more > > features to the driver, but those are not relevant to this discussion. > > > > We can offload crypto operations to the QCE saving CPU cycles but more > importantly, the QCE provides HW based isolation which some vendors care > about. Do you have any concrete proof of anyone using this with a specific Linux kernel feature and actually getting a benefit from it? Just for some additional context, I've been on the Android team for many years and have worked with lots of companies shipping Android devices with Qualcomm SoCs. I also upstreamed the support for the Qualcomm Inline Crypto Engine (ICE) (https://lore.kernel.org/all/20200710072013.177481-6-ebiggers@kernel.org/ https://lore.kernel.org/linux-mmc/20210126001456.382989-9-ebiggers@kernel.org/), which is what people actually use and isn't the same as QCE. The only times the Linux QCE driver has ever come up is when someone used it accidentally and it destroyed their performance (due to the 20-60x slower performance than the CPU) or caused a filesystem hang. These issues get reported to me -- sometimes even from Qualcomm themselves! It's kind of annoying. (Fortunately it's also quite rare, since the vast majority of people just ignore QCE and don't make the mistake of using it in Linux.) As far as I can tell, what actually works and what people actually use in Linux on Qualcomm SoCs is: - The Qualcomm Inline Crypto Engine (ICE) for storage encryption - The ARMv8 Crypto Extensions everywhere else, e.g. dm-verity > These are future plans, yes. But right now we do have active users of this > IP Just because it may be used by the Arm secure world doesn't mean it is useful in Linux. - Eric