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 3F8D0EB64DC for ; Fri, 30 Jun 2023 14:05:34 +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 3D26D2AC4A for ; Fri, 30 Jun 2023 14:05:32 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id AAA9098685E for ; Fri, 30 Jun 2023 14:05:31 +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 09FAE9866EE; Fri, 30 Jun 2023 14:05:31 +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 334D19866ED; Fri, 30 Jun 2023 14:04:19 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R111e4;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_---0VmIpUy0_1688133852; Message-ID: <38fe3702-ea32-0d4a-fe23-cc7dbc823415@linux.alibaba.com> Date: Fri, 30 Jun 2023 22:04:08 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 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 References: <20230628152125-mutt-send-email-mst@kernel.org> <4132affe-9b97-a81f-ad57-50ed4341678b@linux.alibaba.com> <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> From: Heng Qi In-Reply-To: <20230630041337-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 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 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. > >> 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. > > > >>> 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. > >>> 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