From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-comment-return-1079-cohuck=redhat.com@lists.oasis-open.org Sender: 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 DC5E6985EF2 for ; Thu, 20 Feb 2020 08:10:52 +0000 (UTC) Date: Thu, 20 Feb 2020 03:10:38 -0500 From: "Michael S. Tsirkin" Message-ID: <20200220024832-mutt-send-email-mst@kernel.org> References: <20200219075337.23191-1-yuri.benditovich@daynix.com> <20200219075337.23191-2-yuri.benditovich@daynix.com> <86420fd1-cbb4-0105-4114-ca2d6cb3b8ff@redhat.com> <20200219092244-mutt-send-email-mst@kernel.org> <623f76be-bf87-c473-350e-87fe53b41261@redhat.com> <893990295.7352578.1582184463424.JavaMail.zimbra@redhat.com> MIME-Version: 1.0 In-Reply-To: <893990295.7352578.1582184463424.JavaMail.zimbra@redhat.com> Subject: Re: [virtio-comment] [PATCH v4 1/1] virtio-net: Define per-packet hash reporting feature Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline To: Yuri Benditovich Cc: Jason Wang , Yuri Benditovich , virtio-comment@lists.oasis-open.org List-ID: On Thu, Feb 20, 2020 at 02:41:03AM -0500, Yuri Benditovich wrote: >=20 >=20 > =E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81= =E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2= =94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94= =81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81= =E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2= =94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94= =81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81= =E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2= =94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94= =81=E2=94=81=E2=94=81=E2=94=81=E2=94=81 >=20 > From: "Jason Wang" > To: "Michael S. Tsirkin" > Cc: "Yuri Benditovich" , > virtio-comment@lists.oasis-open.org > Sent: Thursday, February 20, 2020 8:38:50 AM > Subject: Re: [virtio-comment] [PATCH v4 1/1] virtio-net: Define per-p= acket > hash reporting feature >=20 >=20 > On 2020/2/19 =E4=B8=8B=E5=8D=8810:23, Michael S. Tsirkin wrote: > > On Wed, Feb 19, 2020 at 08:27:10PM +0800, Jason Wang wrote: > >> On 2020/2/19 =E4=B8=8B=E5=8D=883:53, Yuri Benditovich wrote: > >>> The device MUST set \field{rss_max_indirection_table_length} t= o at > least 128, if it offers > >>> VIRTIO_NET_F_RSS. > >>> @@ -3195,6 +3180,8 @@ \subsection{Device Operation}\label{sec:Dev= ice > Types / Network Device / Device O > >>> le16 csum_start; > >>> le16 csum_offset; > >>> le16 num_buffers; > >>> + le32 hash_value; (Only if VIRTIO_NET_F_HASH_REPORT negot= iated) > >>> + le16 hash_type; (Only if VIRTIO_NET_F_HASH_REPORT negot= iated) > >>> }; > >>> \end{lstlisting} > >> A question here: > >> > >> Consider we introduce VIRTIO_NET_F_FEATURE_INFORMATION in the futu= re: > >> > >> le32 hash_type; // VIRTIO_NET_F_HASH_REPORT > >> le32 feature_information; // VIRTIO_NET_F_FEATURE_INFORMATION > >> > >> What happens if HASH_REPORT is not negotiated, I believe we expect= a > stable > >> ABI(offset) here for feature_information? > >> > >> Thanks > >> > > We'll have to decide at that point ... any better ideas? >=20 >=20 > Not sure but something that is self descriptive? (which could be an > overkill for fields that only need few bytes). >=20 > The problem is that the driver typically wants to know the header size fr= om the > beginning to configure SG table. > So any self-descriptive layout seems good but in practice not so usable, = IMO. We should also look at packing things more tightly down the road. >=20 >=20 > Thanks >=20 >=20 > This publicly archived list offers a means to provide input to the > OASIS Virtual I/O Device (VIRTIO) TC. >=20 > In order to verify user consent to the Feedback License terms and > to minimize spam in the list archive, subscription is required > before posting. >=20 > 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/ >=20 >=20 >=20 This publicly archived list offers a means to provide input to the=0D OASIS Virtual I/O Device (VIRTIO) TC.=0D =0D In order to verify user consent to the Feedback License terms and=0D to minimize spam in the list archive, subscription is required=0D before posting.=0D =0D Subscribe: virtio-comment-subscribe@lists.oasis-open.org=0D Unsubscribe: virtio-comment-unsubscribe@lists.oasis-open.org=0D List help: virtio-comment-help@lists.oasis-open.org=0D List archive: https://lists.oasis-open.org/archives/virtio-comment/=0D Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf= =0D List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lis= ts=0D Committee: https://www.oasis-open.org/committees/virtio/=0D Join OASIS: https://www.oasis-open.org/join/