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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9859C77B72 for ; Tue, 4 Apr 2023 12:54:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234430AbjDDMyH convert rfc822-to-8bit (ORCPT ); Tue, 4 Apr 2023 08:54:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235087AbjDDMyF (ORCPT ); Tue, 4 Apr 2023 08:54:05 -0400 Received: from us-smtp-delivery-44.mimecast.com (unknown [207.211.30.44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 80EC6E60 for ; Tue, 4 Apr 2023 05:54:03 -0700 (PDT) Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-25-o99LjM4cOAWcrt0bL_JNdg-1; Tue, 04 Apr 2023 08:53:46 -0400 X-MC-Unique: o99LjM4cOAWcrt0bL_JNdg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id AC39588CC40; Tue, 4 Apr 2023 12:53:45 +0000 (UTC) Received: from hog (unknown [10.39.192.141]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8312C440BC; Tue, 4 Apr 2023 12:53:44 +0000 (UTC) Date: Tue, 4 Apr 2023 14:53:43 +0200 From: Sabrina Dubroca To: Emeel Hakim Cc: Leon Romanovsky , "davem@davemloft.net" , "kuba@kernel.org" , "pabeni@redhat.com" , "edumazet@google.com" , "netdev@vger.kernel.org" Subject: Re: [PATCH net-next v2 1/4] vlan: Add MACsec offload operations for VLAN interface Message-ID: References: <20230329122107.22658-1-ehakim@nvidia.com> <20230329122107.22658-2-ehakim@nvidia.com> <20230329184201.GB831478@unreal> <20230330185656.GZ831478@unreal> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: queasysnail.net Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 2023-04-03, 09:29:28 +0000, Emeel Hakim wrote: > > > > -----Original Message----- > > From: Sabrina Dubroca > > Sent: Thursday, 30 March 2023 23:33 > > To: Leon Romanovsky > > Cc: Emeel Hakim ; davem@davemloft.net; kuba@kernel.org; > > pabeni@redhat.com; edumazet@google.com; netdev@vger.kernel.org > > Subject: Re: [PATCH net-next v2 1/4] vlan: Add MACsec offload operations for VLAN > > interface > > > > External email: Use caution opening links or attachments > > > > > > 2023-03-30, 21:56:56 +0300, Leon Romanovsky wrote: > > > On Thu, Mar 30, 2023 at 07:19:21PM +0200, Sabrina Dubroca wrote: > > > > 2023-03-29, 21:42:01 +0300, Leon Romanovsky wrote: > > > > > On Wed, Mar 29, 2023 at 04:43:59PM +0200, Sabrina Dubroca wrote: > > > > > > 2023-03-29, 15:21:04 +0300, Emeel Hakim wrote: > > > > > > > Add support for MACsec offload operations for VLAN driver to > > > > > > > allow offloading MACsec when VLAN's real device supports > > > > > > > Macsec offload by forwarding the offload request to it. > > > > > > > > > > > > > > Signed-off-by: Emeel Hakim > > > > > > > --- > > > > > > > V1 -> V2: - Consult vlan_features when adding NETIF_F_HW_MACSEC. > > > > > > > > > > > > Uh? You're not actually doing that? You also dropped the changes > > > > > > to vlan_dev_fix_features without explaining why. > > > > > > > > > > vlan_dev_fix_features() relies on real_dev->vlan_features which > > > > > was set in mlx5 part of this patch. > > > > > > > > > > 643 static netdev_features_t vlan_dev_fix_features(struct net_device *dev, > > > > > 644 netdev_features_t features) > > > > > 645 { > > > > > ... > > > > > 649 > > > > > 650 lower_features = netdev_intersect_features((real_dev- > > >vlan_features | > > > > > 651 NETIF_F_RXCSUM), > > > > > 652 real_dev->features); > > > > > > > > > > This part ensure that once real_dev->vlan_features and > > > > > real_dev->features have NETIF_F_HW_MACSEC, the returned features will > > include NETIF_F_HW_MACSEC too. > > > > > > > > Ok, thanks. > > > > > > > > But back to the issue of vlan_features, in vlan_dev_init: I'm not > > > > convinced NETIF_F_HW_MACSEC should be added to hw_features based on > > > > ->features. That would result in a new vlan device that can't > > > > ->offload > > > > macsec at all if it was created at the wrong time (while the lower > > > > device's macsec offload was temporarily disabled). > > > > > > Sorry, I'm new to this netdev features zoo, but if I read correctly > > > Documentation/networking/netdev-features.rst, the ->features is the > > > list of enabled ones: > > > > > > 29 2. netdev->features set contains features which are currently enabled > > > 30 for a device. This should be changed only by network core or in > > > 31 error paths of ndo_set_features callback. > > > > > > And user will have a chance to disable it for VLAN because it was > > > added to ->hw_features: > > > > > > 24 1. netdev->hw_features set contains features whose state may possibly > > > 25 be changed (enabled or disabled) for a particular device by user's > > > 26 request. This set should be initialized in ndo_init callback and not > > > 27 changed later. > > > > > > So how can VLAN be created with NETIF_F_HW_MACSEC while real_dev > > > mcasec offload is disabled? > > > > I'm proposing that be VLAN device be created with the capability (->hw_features > > contains NETIF_F_HW_MACSEC) but disabled (->features doesn't contain > > NETIF_F_HW_MACSEC). That way, if NETIF_F_HW_MACSEC is re-enabled on the > > lower device, you don't need to destroy the VLAN device to enable macsec offload > > on it as well. You still won't be able to enable macsec offload on the VLAN device > > unless it's active on the real NIC. > > > > I think whether the lower device currently has NETIF_F_HW_MACSEC should only > > affect whether you can enable the feature on the vlan device right now. What > > feature is enabled at creation time should be irrelevant. > > Thanks for the proposal Sabrina, I'm also new to this netdev features zone so IIUC your'e > proposing that we have NETIF_F_HW_MACSEC added to the dev->hw_features upon > vlan_dev_init, but disabled (we don’t add it to dev->features) , and upon vlan_dev_fix_features > we check if the real_device have NETIF_F_HW_MACSEC enabled (after the intersect with the real_dev->vlan_features) > and if so we add it to the features. > > So something like: > > static int vlan_dev_init(struct net_device *dev) > { > ... > dev->features |= dev->hw_features | NETIF_F_LLTX; > dev->hw_features |= NETIF_F_HW_MACSEC; > ... > } That would be adding the NETIF_F_HW_MACSEC to all VLAN devices, whether the lower device advertises this feature or not. That's wrong. What I had in mind was: if (real_dev->vlan_features & NETIF_F_HW_MACSEC) dev->hw_features |= NETIF_F_HW_MACSEC; And we should enable it by default when the lower device has it enabled, which would be the case with this: @@ -572,6 +572,9 @@ static int vlan_dev_init(struct net_device *dev) NETIF_F_HIGHDMA | NETIF_F_SCTP_CRC | NETIF_F_ALL_FCOE; + if (real_dev->vlan_features & NETIF_F_HW_MACSEC) + dev->hw_features |= NETIF_F_HW_MACSEC; + dev->features |= dev->hw_features | NETIF_F_LLTX; netif_inherit_tso_max(dev, real_dev); if (dev->features & NETIF_F_VLAN_FEATURES) What I meant by "but disabled" in my previous email was that if the lower device currently has NETIF_F_HW_MACSEC, the new vlan device should also have it disabled, not that it should always be disabled on creation. > static netdev_features_t vlan_dev_fix_features(struct net_device *dev, > netdev_features_t features) > { > ... > if (lower_features & NETIF_F_HW_MACSEC) > features |= NETIF_F_HW_MACSEC; > > return features; > } I don't think NETIF_F_HW_MACSEC is "special" enough to require hacks in vlan_dev_fix_features. IMHO modifying vlan_dev_fix_features should only happen if we have no other way to implement a consistent and useful behavior. I don't think that's the case here. -- Sabrina