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 9FBC0C678D4 for ; Fri, 3 Mar 2023 13:13:44 +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 AFC231EAF0 for ; Fri, 3 Mar 2023 13:13:43 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 8BC6C9867AC for ; Fri, 3 Mar 2023 13:13:43 +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 713929867A1; Fri, 3 Mar 2023 13:13:43 +0000 (UTC) Mailing-List: contact virtio-dev-help@lists.oasis-open.org; run by ezmlm List-Id: 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 617F19867A2 for ; Fri, 3 Mar 2023 13:13:43 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: BLmh7KwoMb2QStY8-ZZPzQ-1 Date: Fri, 3 Mar 2023 08:13:37 -0500 From: Stefan Hajnoczi To: "Michael S. Tsirkin" Cc: virtio-comment@lists.oasis-open.org, virtio-dev@lists.oasis-open.org, jasowang@redhat.com, cohuck@redhat.com, sgarzare@redhat.com, nrupal.jani@intel.com, Piotr.Uminski@intel.com, hang.yuan@intel.com, virtio@lists.oasis-open.org, Zhu Lingshan , pasic@linux.ibm.com, Shahaf Shuler , Parav Pandit , Max Gurtovoy Message-ID: <20230303131337.GA2866370@fedora> References: <910b3607a5f255134d30b3e1233e564f564eafb8.1677761896.git.mst@redhat.com> <20230302201011.GB2554028@fedora> <20230302185214-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="hkbgpoq/+xtB5seq" Content-Disposition: inline In-Reply-To: <20230302185214-mutt-send-email-mst@kernel.org> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Subject: [virtio-dev] Re: [PATCH v10 03/10] admin: introduce group administration commands --hkbgpoq/+xtB5seq Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Mar 02, 2023 at 06:57:24PM -0500, Michael S. Tsirkin wrote: > On Thu, Mar 02, 2023 at 03:10:11PM -0500, Stefan Hajnoczi wrote: > > On Thu, Mar 02, 2023 at 08:05:02AM -0500, Michael S. Tsirkin wrote: > > > This introduces a general structure for group administration commands, > > > used to control device groups through their owner. > > >=20 > > > Following patches will introduce specific commands and an interface f= or > > > submitting these commands to the owner. > > >=20 > > > Signed-off-by: Max Gurtovoy > > > Signed-off-by: Michael S. Tsirkin > > > --- > > > admin.tex | 108 +++++++++++++++++++++++++++++++++++++++++++++= ++ > > > introduction.tex | 3 ++ > > > 2 files changed, 111 insertions(+) > > >=20 > > > diff --git a/admin.tex b/admin.tex > > > index 3dc47be..7e28b77 100644 > > > --- a/admin.tex > > > +++ b/admin.tex > > > @@ -46,4 +46,112 @@ \section{Device groups}\label{sec:Basic Facilitie= s of a Virtio Device / Device g > > > PCI transport (see \ref{sec:Virtio Transport Options / Virtio Over P= CI Bus}). > > > \end{description} > > > =20 > > > +\subsection{Group administration commands}\label{sec:Basic Facilitie= s of a Virtio Device / Device groups / Group administration commands} > > > =20 > > > +The driver sends group administration commands to the owner device of > >=20 > > I notice that the terminology is simply "the driver". "Owner driver" > > and "group member driver" might be clearer because there will be two > > (possibly different) drivers involved. >=20 > Hmm I don't really want to repeat owner everywhere. > I will clarify that in this section simple "driver" and "device" are > owner, "member device" and "member driver" is always called explicitly. Sounds good. > > > +a group to control member devices of the group. > > > +This mechanism can > > > +be used, for example, to configure a member device before it is > > > +initialized by its driver. > > > +\footnote{The term "administration" is intended to be interpreted > > > +widely to include any kind of control. See specific commands > > > +for detail.} > > > + > > > +All the group administration commands are of the following form: > > > + > > > +\begin{lstlisting} > > > +struct virtio_admin_cmd { > > > + /* Device-readable part */ > > > + le16 opcode; > > > + /* > > > + * 1 - SR-IOV > > > + * 2 - 65535 reserved > > > + */ > > > + le16 group_type; > > > + /* unused, reserved for future extensions */ > > > + u8 reserved1[12]; > > > + le64 group_member_id; > > > + u8 command_specific_data[]; > > > + > > > + /* Device-writable part */ > > > + le16 status; > > > + le16 status_qualifier; > > > + /* unused, reserved for future extensions */ > > > + u8 reserved2[4]; > > > + u8 command_specific_result[]; > > > +}; > > > +\end{lstlisting} > > > + > > > +For all commands, \field{opcode}, \field{group_type} and if > > > +necessary \field{group_member_id} and \field{command_specific_data} = are > > > +set by the driver, and the owner device sets \field{status} and if > > > +needed \field{status_qualifier} and > > > +\field{command_specific_result}. > > > + > > > +Generally, any unused device-readable fields are set to zero by the = driver > > > +and ignored by the device. Any unused device-writeable fields are s= et to zero > > > +by the device and ignored by the driver. > > > + > > > +\field{opcode} specifies the command. The valid > > > +values for \field{opcode} can be found in the following table: > > > + > > > +\begin{tabular}{|l|l|} > > > +\hline > > > +opcode & Name & Command Description \\ > > > +\hline \hline > > > +0x0000 - 0x7FFF & - & Group administration commands \\ > > > +\hline > > > +0x8000 - 0xFFFF & - & Reserved \\ > > > +\hline > > > +\end{tabular} > >=20 > > I thought all commands are "group administration commands" but this > > table makes it look like they are just a subset (0x0000 - 0x7FFF) of > > group administration commands, which is a paradox. >=20 > Well the rest are reserved, maybe we will have more command types who > knows. No? I see. Does that mean the reserved commands don't need to be in the same format as struct virtio_admin_cmd? The entire section is called "Group administration commands" but I get the impression it's talking both about admin virtqueue commands in general and specifically about group administration commands. Is it possible to structure this as follows: Admin Commands ...common stuff... Group Administration Commands (0x0000-0x7fff) ...specific to group administration commands... Reserved (0x8000-0xffff) > > > + > > > +The \field{group_type} specifies the group type identifier. > > > +The \field{group_member_id} specifies the member identifier within t= he group. > > > +See section \ref{sec:Introduction / Terminology / Device group} > > > +for the definition of the group type identifier and group member > > > +identifier. > > > + > > > +The following table describes possible \field{status} values; > > > +to simplify common implementations, they are intentionally > > > +matching common \hyperref[intro:errno]{Linux error names and numbers= }: > > > + > > > +\begin{tabular}{|l|l|l|} > > > +\hline > > > +Status (decimal) & Name & Description \\ > > > +\hline \hline > > > +00 & VIRTIO_ADMIN_STATUS_OK & successful completion \\ > > > +\hline > > > +22 & VIRTIO_ADMIN_STATUS_EINVAL & invalid command \\ > > > +\hline > > > +other & - & group administration command error \\ > > > +\hline > > > +\end{tabular} > > > + > > > +When \field{status} is VIRTIO_ADMIN_STATUS_OK, \field{status_qialifi= er} > >=20 > > s/qialifier/qualifier/ > >=20 > > > +is reserved and set to zero by the device. > > > + > > > +When \field{status} is VIRTIO_ADMIN_STATUS_EINVAL, > > > +the following table describes possible \field{status_qialifier} valu= es: > >=20 > > s/qialifier/qualifier/ > >=20 > > > +\begin{tabular}{|l|l|l|} > > > +\hline > > > +Status & Name & Description \\ > > > +\hline \hline > > > +0x00 & VIRTIO_ADMIN_STATUS_Q_INVALID_COMMAND & command error: no= additional information \\ > > > +\hline > > > +0x01 & VIRTIO_ADMIN_STATUS_Q_INVALID_OPCODE & unsupported or in= valid \field{opcode} \\ > > > +\hline > > > +0x02 & VIRTIO_ADMIN_STATUS_Q_INVALID_FIELD & unsupported or inv= alid field within \field{command_specific_data} \\ > > > +\hline > > > +0x03 & VIRTIO_ADMIN_STATUS_Q_INVALID_GROUP & unsupported or inv= alid \field{group_type} \\ > > > +\hline > > > +0x04 & VIRTIO_ADMIN_STATUS_Q_INVALID_MEMBER & unsupported or in= valid \field{group_member_id} \\ > > > +\hline > > > +0x05-0xFFFF & - & reserved for future use \\ > > > +\hline > > > +\end{tabular} > > > + > > > +Each command uses a different \field{command_specific_data} and > > > +\field{command_specific_result} structures and the length of > > > +\field{command_specific_data} and \field{command_specific_result} > > > +depends on these structures and is described separately or is > > > +implicit in the structure description. > >=20 > > On more thing: > >=20 > > Does the owner device see commands in order but may complete them in any > > order? > >=20 > > I think this information might be useful just to make it clear that > > driver authors shouldn't make assumptions about ordering and completion > > order, e.g. pipelining a bunch of dependent commands doesn't work > > because the first command is not necessarily completed before the second > > command is started. >=20 > I think this is discussed when we discuss sending commands through vq. > in this section it's just about commands generally whatever the way > to send them to device. no? Okay. I'm reading this patch series linearly and the question popped into my mind here. Glad it's already covered elsewhere. Stefan --hkbgpoq/+xtB5seq Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmQB8oEACgkQnKSrs4Gr c8iEJggAl4TQD1YU+Lx9Ua0jJoS80G6DBZ7tJhvQ/tMXpeva1685SUe3lQoUPAmD PEZLEGw8tc3pqkwRwQMX7D6u/serw4l8/Ve766pJob05pJ8JmSsqo2TmWCe45140 MRj4k9F0cOHujjIrEOIPR+bdv6OZV+DK9R9o21lc6DXuwUZmVSrQH8ztxY0mCKqw f/AKLopmki/MSz4k9EDD8UshIdfo+A3e9yVgvup+yvySC1ViQrkj81N3mM33ZFS+ UNfWZEhEQDKP5oHm+lQyrd0bR1WKMIDDi27LPKGxE+HDVuCHdGLWI39V6jz2qulK 9mMVLRFifhCImCP1vCldKAlEqkcBBg== =FaQR -----END PGP SIGNATURE----- --hkbgpoq/+xtB5seq--