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 ws5-mx01.kavi.com (ws5-mx01.kavi.com [34.193.7.191]) (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 7241CEB64D7 for ; Fri, 30 Jun 2023 16:09:25 +0000 (UTC) Received: from lists.oasis-open.org (oasis.ws5.connectedcommunity.org [10.110.1.242]) by ws5-mx01.kavi.com (Postfix) with ESMTP id 1AA152AC46 for ; Fri, 30 Jun 2023 16:09:24 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 129FB9866FC for ; Fri, 30 Jun 2023 16:09:24 +0000 (UTC) Received: from host09.ws5.connectedcommunity.org (host09.ws5.connectedcommunity.org [10.110.1.97]) by lists.oasis-open.org (Postfix) with QMQP id 02EB59866ED; Fri, 30 Jun 2023 16:09:24 +0000 (UTC) Mailing-List: contact virtio-dev-help@lists.oasis-open.org; run by ezmlm List-ID: Sender: Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id E42B09866EE; Fri, 30 Jun 2023 16:09:20 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R201e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046051;MF=hengqi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0VmJ4mtq_1688141350; Date: Sat, 1 Jul 2023 00:09:09 +0800 From: Heng Qi To: "Michael S. Tsirkin" Cc: Parav Pandit , "virtio-comment@lists.oasis-open.org" , "virtio-dev@lists.oasis-open.org" , Yuri Benditovich , Xuan Zhuo , Jason Wang Message-ID: <20230630160909.GA43312@h68b04307.sqa.eu95> References: <20230629074627-mutt-send-email-mst@kernel.org> <20230630005420.GC77232@h68b04307.sqa.eu95> <20230630014917-mutt-send-email-mst@kernel.org> <20230630041337-mutt-send-email-mst@kernel.org> <38fe3702-ea32-0d4a-fe23-cc7dbc823415@linux.alibaba.com> <20230630102758-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230630102758-mutt-send-email-mst@kernel.org> User-Agent: Mutt/1.5.21 (2010-09-15) Subject: [virtio-dev] Re: [virtio-comment] Re: [virtio-dev] Re: [virtio-comment] Re: [virtio-dev] RE: [virtio-comment] RE: [PATCH v19] virtio-net: support inner header hash On Fri, Jun 30, 2023 at 10:52:25AM -0400, Michael S. Tsirkin wrote: > On Fri, Jun 30, 2023 at 10:04:08PM +0800, Heng Qi wrote: > > > > > > 在 2023/6/30 下午4:17, Michael S. Tsirkin 写道: > > > On Fri, Jun 30, 2023 at 02:15:13PM +0800, Heng Qi wrote: > > > > > > > > 在 2023/6/30 下午1:59, Michael S. Tsirkin 写道: > > > > > On Fri, Jun 30, 2023 at 09:55:41AM +0800, Heng Qi wrote: > > > > > > 在 2023/6/30 上午9:36, Parav Pandit 写道: > > > > > > > > From: Heng Qi > > > > > > > > Sent: Thursday, June 29, 2023 8:54 PM > > > > > > > > > > > > > > > > On Thu, Jun 29, 2023 at 04:59:28PM +0000, Parav Pandit wrote: > > > > > > > > > > From: Michael S. Tsirkin > > > > > > > > > > Sent: Thursday, June 29, 2023 7:48 AM > > > > > > > > > > > > struct virtio_net_hash_config reserved is fine. > > > > > > > > > > > +1. > > > > > > > > > > > > > > > > > > > > > > Inner header hash is orthogonal to RSS, and it's fine to have its > > > > > > > > > > > own structure and commands. > > > > > > > > > > > There is no need to send additional RSS fields when we configure > > > > > > > > > > > inner header hash. > > > > > > > > > > > > > > > > > > > > > > Thanks. > > > > > > > > > > Not RSS, hash calculations. It's not critical, but I note that > > > > > > > > > > practically you said you will enable this with symmetric hash so it > > > > > > > > > > makes sense to me to send this in the same command with the key. > > > > > > > > > > > > > > > > > > > In the v19, we have, > > > > > > > > > > > > > > > > > > +\item[VIRTIO_NET_F_HASH_TUNNEL] Requires VIRTIO_NET_F_CTRL_VQ > > > > > > > > along with VIRTIO_NET_F_RSS or VIRTIO_NET_F_HASH_REPORT. > > > > > > > > > So it is done along with rss, so in same struct as rss config is fine. > > > > > > > > Do you mean having both virtio_net_rss_config and virtio_net_hash_config > > > > > > > > have enabled_hash_types? > > > > > > > > Like this: > > > > > > > > > > > > > > > > struct virtio_net_rss_config { > > > > > > > > le32 hash_types; > > > > > > > > le16 indirection_table_mask; > > > > > > > > struct rss_rq_id unclassified_queue; > > > > > > > > struct rss_rq_id indirection_table[indirection_table_length]; > > > > > > > > le16 max_tx_vq; > > > > > > > > u8 hash_key_length; > > > > > > > > u8 hash_key_data[hash_key_length]; > > > > > > > > + le32 enabled_tunnel_types; > > > > > > > > }; > > > > > > > > > > > > > > > > struct virtio_net_hash_config { > > > > > > > > le32 hash_types; > > > > > > > > - le16 reserved[4]; > > > > > > > > + le32 enabled_tunnel_types; > > > > > > > > + le16 reserved[2]; > > > > > > > > u8 hash_key_length; > > > > > > > > u8 hash_key_data[hash_key_length]; > > > > > > > > }; > > > > > Oh, I forgot that rss and hash had identical structures. > > > > > And we want to keep that I think. > > > > > > > > > > But now it's not clear to me: does the same enabled_tunnel_types > > > > > apply to both hash calculation and rss? > > > > Yes. What I'm trying to say is that making the inner header hash and > > > > RSS/hash calculation clear delimitation will make everything easier. > > > > The inner header hash just configures enabled_tunnel_types. > > > > The RSS/hash calculation is configured as before without modification. > > > > > > > > > I note we normally have separate configs for hash and rss. > > > > > So to keep it consistent what should we do? two set commands? > > > > As I explained above, like outer udp port hash/symmetric toeplitz hash, > > > > these fall under the umbrella of RSS/hash calculation. > > > Yes but note that symmetric toeplitz hash has to be configured > > > separately for RSS and for hashing. > > > > Yes, this requires a field like \field{mode}, with different values > > corresponding to different hashing algorithms, such as toeplitz or symmetric > > toeplitz. > > The outer port hash belongs to RSS/hash calculation. > > So there will be need for more fields. Yes, the mode field is outside of RSS/hash, as it should be at a higher level than RSS/hash. > To me this implies extending with struct virtio_net_rss_tunnel_config > is a better idea since we then have some reserved space to > put "mode" down the road (in the reserved[6] space below). > > No? > > > > > > > > Let's keep the inner header hash simple. > > > > > > > > > Or does enabled_tunnel_types apply to both rss and hash? > > > > Certainly. See: > > > > > > > >     +\item[VIRTIO_NET_F_HASH_TUNNEL] Requires VIRTIO_NET_F_CTRL_VQ along > > > > with VIRTIO_NET_F_RSS or VIRTIO_NET_F_HASH_REPORT. > > > > > > It does not really say that. > > Oh! I understand now. I think a VIRTIO_NET_CTRL_HASH_TUNNEL_SET command is > > applied to hash and RSS. Yes. > > When one wants to configure inner header hash separately, use > > VIRTIO_NET_CTRL_HASH_TUNNEL_SET command to send enabled_tunnel_types > > separately. > > When one wants to configure both inner header hash and RSS/hash, use > > VIRTIO_NET_CTRL_HASH_TUNNEL_SET together with > > VIRTIO_NET_CTRL_MQ_RSS_CONFIG/VIRTIO_NET_CTRL_MQ_HASH_CONFIG. > > The inner header hash is decoupled from RSS/hash, and no extra fields will > > be sent every configuration. > > But why is tunnel so different? Rest of things can be configured > for hash and for rss separately. > It dawned on me where we were not aligned. Please see more. > > For example I can configure hash for IPv4 and IPv6 but RSS only for > IPv6. Can we have this behavior? I don't think so, RSS and Hash have the same device configuration, which is determined by the *last* *device-received* command of the VIRTIO_NET_CTRL_MQ class. See the spec: "If more than one multiqueue mode is negotiated, the resulting device configuration is defined by the last command sent by the driver." > But for some reason, if I configure tunnel for GRE it will > affect both hash and RSS. Why? It seems quite possible to me that I > was offload for hash for GRE but don't want to use it > for RSS to avoid RX underrun issues we discussed. This makes sense. So the scenario you are referring to should be: The configuration of RSS/HASH is IPV6, but we have configured GRE_rfc2784 (both inner and outer headers are IPv4). When the device receives a GRE_rfc2784 packet, which matches the GRE_rfc2784 encapsulation type, and then the device need to calculate the hash based on RSS/Hash, but it turns out that the configured IPv6 of RSS/hash does not match the inner IPv4. Then nothing happened. ? If yes, I agree to virtio_net_rss_tunnel_config and virtio_net_hash_tunnel_config. > > > > > > > > > > > > > > > > We should have reserved more space. We can still do it if you like: > > > > > > > > > > struct virtio_net_rss_tunnel_config { > > > > > le32 enabled_tunnel_types; > > > > > le16 reserved[6]; > > > > > struct virtio_net_rss_config hash; > > > > > }; > > > > > > > > > > struct virtio_net_hash_tunnel_config { > > > > > le32 enabled_tunnel_types; > > > > > le16 reserved[6]; > > > > > struct virtio_net_hash_config hash; > > > > > }; > > > > > > > > > > ? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > If yes, this should have been discussed in v10 [1] before, enabled_tunnel_types > > > > > > > > in virtio_net_rss_config will follow the variable length field and cause > > > > > > > > misalignment. > > > > > > > > > > > > > > > > If we let the inner header hash reuse the virtio_net_hash_config structure, it > > > > > > > > can work, but the only disadvantage is that the configuration of the inner > > > > > > > > header hash and *RSS*(not hash calculations) becomes somewhat coupled. > > > > > > > > Just imagine: > > > > > > > > If the driver and the device negotiated VIRTIO_NET_F_HASH_TUNNEL and > > > > > > > > VIRTIO_NET_F_RSS, but did not negotiate VIRTIO_NET_F_HASH_REPORT, 1. > > > > > > > > then if we only want to configure the inner header hash (such as > > > > > > > > enabled_tunnel_types), it is good for us to send virtio_net_hash_config alone; > > > > > > > > 2. but then if we want to configure the inner header hash and RSS (such as > > > > > > > > indirection table), we need to send all virtio_net_rss_config and > > > > > > > > virtio_net_hash_config once, because virtio_net_rss_config now does not carry > > > > > > > > enabled_tunnel_types due to misalignment. > > > > > > > > > > > > > > > > So, I think the following structure will make it clearer to configure inner header > > > > > > > > hash and RSS/hash calculation. > > > > > > > > But in any case, if we still propose to reuse virtio_net_hash_config proposal, I > > > > > > > > am ok, no objection: > > > > > > > > > > > > > > > > 1. The supported_tunnel_types are placed in the device config space; > > > > > > > > > > > > > > > Yes. I forgot the variable length part. > > > > > > > The second disadvantage I remember now is one need to resupply all the rss hash config parameter and device needs to compare and modify for this one field. > > > > > Or it could be an advantage since one normally wants to configure a > > > > > symmetric key with this. Further device can just use the new config > > > > When we want to configure the hash key, he continues to use the previous > > > > rss/hash calculation interface. This is ok. > > > > > > > > Thanks. > > > I don't understand this sentence. My point is simply that > > > to use the tunnel key has to be symmetric. So two commands > > > will be required: one to set tunnel types, one to > > > set the key. > > > > Yes, you are right. Then one should be VIRTIO_NET_CTRL_HASH_TUNNEL_SET and > > the other > > should be VIRTIO_NET_CTRL_MQ_RSS_CONFIG/VIRTIO_NET_CTRL_MQ_HASH_CONFIG. > > > > Thanks. > > Well that is still 1 command for tunnels that affects both rss and > hashing. Why not 2 commands for rss and for hashing? > I think I get you now. If the above is correct, then I think we should have the following: VIRTIO_NET_CTRL_TUNNEL_RSS -> virtio_net_rss_tunnel_config VIRTIO_NET_CTRL_TUNNEL_HASH -> virtio_net_hash_tunnel_config ? Thanks! > > > > > > > > > with no need to check what the old one was. I'd call it a wash. > > > > > > > > > > > > Given these two disadvantages, I also prefer independent SET command the way you have it. > > > > > > OK, let's wait for Michael's input again. > > > > > > > > > > > > Thanks. > > > > > This part is not critical to me, but now I understand we need two sets of SET commands. > > > > > > > > > > > > > > > > > > 2. > > > > > > > > Reserve the following structure: > > > > > > > > > > > > > > > > struct virtnet_hash_tunnel { > > > > > > > > le32 enabled_tunnel_types; > > > > > > > > }; > > > > > > > > > > > > > > > > 3. Reserve the SET command for enabled_tunnel_types and remove the GET > > > > > > > > command for enabled_tunnel_types. > > > > > > > > > > > > > > > > [1] https://lists.oasis-open.org/archives/virtio-dev/202303/msg00317.html > > > > > > > > > > > > > > > > Thanks a lot! > > > > > --------------------------------------------------------------------- > > > > > To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org > > > > > For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org > > > > > > This publicly archived list offers a means to provide input to the > > > OASIS Virtual I/O Device (VIRTIO) TC. > > > > > > In order to verify user consent to the Feedback License terms and > > > to minimize spam in the list archive, subscription is required > > > before posting. > > > > > > Subscribe: virtio-comment-subscribe@lists.oasis-open.org > > > Unsubscribe: virtio-comment-unsubscribe@lists.oasis-open.org > > > List help: virtio-comment-help@lists.oasis-open.org > > > List archive: https://lists.oasis-open.org/archives/virtio-comment/ > > > Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf > > > List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lists > > > Committee: https://www.oasis-open.org/committees/virtio/ > > > Join OASIS: https://www.oasis-open.org/join/ --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org