From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by dpdk.org (Postfix) with ESMTP id C9B3D69D4 for ; Fri, 24 Mar 2017 13:53:14 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=intel.com; i=@intel.com; q=dns/txt; s=intel; t=1490359994; x=1521895994; h=from:to:cc:subject:date:message-id:references: in-reply-to:content-transfer-encoding:mime-version; bh=Qxzkz83NqYU2pe1RaPDtQNp63850HHLxpA6hDswqc5k=; b=eRPgBNlMByiQ9QYt4u8fQfhcX8B4tKLVmCK5vkSl19iKqj1d84pj6JCJ 6VwH2fuAqmmDGhBmp1+FmKMAXNPbZA==; Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Mar 2017 05:53:13 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.36,214,1486454400"; d="scan'208";a="1146479708" Received: from irsmsx107.ger.corp.intel.com ([163.33.3.99]) by fmsmga002.fm.intel.com with ESMTP; 24 Mar 2017 05:53:12 -0700 Received: from irsmsx111.ger.corp.intel.com (10.108.20.4) by IRSMSX107.ger.corp.intel.com (163.33.3.99) with Microsoft SMTP Server (TLS) id 14.3.248.2; Fri, 24 Mar 2017 12:52:30 +0000 Received: from irsmsx101.ger.corp.intel.com ([169.254.1.186]) by irsmsx111.ger.corp.intel.com ([169.254.2.242]) with mapi id 14.03.0248.002; Fri, 24 Mar 2017 12:52:30 +0000 From: "Trahe, Fiona" To: "Doherty, Declan" , "dev@dpdk.org" , "De Lara Guarch, Pablo" CC: "Trahe, Fiona" Thread-Topic: [dpdk-dev] [PATCH] cryptodev: add API note Thread-Index: AQHSo/wAeLEetjuyzE+FTMyzI7NZOqGj0ZUAgAAVjnA= Date: Fri, 24 Mar 2017 12:52:29 +0000 Message-ID: <348A99DA5F5B7549AA880327E580B435891C21F1@IRSMSX101.ger.corp.intel.com> References: <1490290570-14651-1-git-send-email-fiona.trahe@intel.com> <927ebdcb-132e-b1a6-e427-fa60cb8ac3b3@intel.com> In-Reply-To: <927ebdcb-132e-b1a6-e427-fa60cb8ac3b3@intel.com> Accept-Language: en-IE, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiYmUyNjFmNjQtMGU4Zi00MGUzLTg4OWQtZWE0NTZlZjYxNjA5IiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX0lDIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE1LjkuNi42IiwiVHJ1c3RlZExhYmVsSGFzaCI6IjR1OU9yZDk4TUJqbEdVTUp0SERIOVI3QW9hREkzSm13ZGVNYVFzbmFjZFE9In0= x-ctpclassification: CTP_IC x-originating-ip: [163.33.239.181] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [PATCH] cryptodev: add API note X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Mar 2017 12:53:15 -0000 Hi Declan, > -----Original Message----- > From: Doherty, Declan > Sent: Friday, March 24, 2017 10:53 AM > To: Trahe, Fiona ; dev@dpdk.org; De Lara Guarch, > Pablo > Subject: Re: [dpdk-dev] [PATCH] cryptodev: add API note >=20 > On 23/03/2017 5:36 PM, Fiona Trahe wrote: > > Add note to cryptodev API that chained mbufs > > are not supported in DOCSISBPI mode. > > > > Signed-off-by: Fiona Trahe > > --- > ... > > >=20 >=20 > Hey Fiona, >=20 > Is this really a limitation of DOCSISBPI mode or just the PMDs which > currently support these operations. I don't see any reason why DOCSISBPI > mode cipher operation precludes scatter gather operations on the source > payload. >=20 The DOCSISBPI spec in section I.12 Fragmented Packet Encryption https://apps.cablelabs.com/specification/CM-SP-SECv3.1 says "When a packet is fragmented, each fragment is independently encrypted= using CBC mode with residual block processing" Of course that doesn't guarantee that an application won't take one of thos= e fragments and split it across multiple mbufs. But I checked with some sub= ject matter experts who didn't see a use-case for it. Due to the nature of DOCSIS there would be a performance impact in derefere= ncing through chained mbufs to get the address of the residual block, on th= at basis it seems like a better idea to preclude this on the API rather tha= n having every PMD separately document a limitation or implement a less-per= formant path that's unlikely to be used. > If there is some fundamental reason why scatter gather operations can't > be supported I think documenting this in the rte_crypto_cipher_algorithm > enumeration comments make more sense than in the rte_crypto_sym_op > structure, as we already specify extra requirements > RTE_CRYPTO_CIPHER_AES_GCM and RTE_CRYPTO_CIPHER_AES_CCM there. It seems to me that this constraint is similar to the notes on many of the = other fields=20 in rte_crypto_sym_op.=20 The CCM/GCM comments on the other hand would not fit so well on the xform s= truct=20 as they're linking fields on both auth and cipher xforms so the comment wou= ld have to=20 be duplicated in 2 places, so works better on the enum. But I don't feel strongly about where it goes, if you still prefer (and agr= ee it's ok to add this constraint on the API) I can move it to the enum.