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 1DB5DC64EC4 for ; Fri, 3 Mar 2023 13:18:53 +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 3D25C2AC58 for ; Fri, 3 Mar 2023 13:18:53 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 275EE9867AC for ; Fri, 3 Mar 2023 13:18:53 +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 1A47E9867A1; Fri, 3 Mar 2023 13:18:53 +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 099FB9867A2 for ; Fri, 3 Mar 2023 13:18:53 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: eFqx_qyWN5O1kwfcuo043g-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1677849528; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=KTHkenJsHD8kvEiOtnajHo3UxPPaqr1sFVjiEMU8YEU=; b=FHLpCGcL4PyGmVEWaG39R5hDjf1DMvJ8zHcsUIp7E5G1B7QupT/QbzzEnKKqAJVy3b Fmf3E6gKgQiwb3+IvJ/OC4B99QgPWcNG2vEGuUZO+E8cXvlZrlBNuS8eLD7P3z3pCcrA 87+Yf9qfu23gDbk7Bfvcic/40VmtcUrnwrT9aRx2OPpzBxFhx6L+J2NX4Ah+nHclhdhQ FvpwFwQH3J2e2BedJNPl6Kt9W7jwq/a0Y5n6myffOa/PDGEW9aiu2CIWnvS9PFgxHiEE yzM/LcJLpR8Habzx5aG2Ne2xl3gNGOwiepEx7dZw5F/lmOSlZOY17pyOIpNehus3FNd2 3myg== X-Gm-Message-State: AO0yUKXF+Ckd7p0u/+GE7bWEYwDu3Btw7Z1opFpbW+I6a3KU8Z88GhBx 44EBacXZt11km9pwtFuVtDaWBZAuZxpPfONuzMa7uHF8cp2kcp9unEPPK0FPltah1DEZeGVo1Hn wB6gnlCRwLHeGLfl3UuU+Do67ma0A X-Received: by 2002:a05:600c:1d1a:b0:3eb:3e75:5d6e with SMTP id l26-20020a05600c1d1a00b003eb3e755d6emr1186419wms.18.1677849527742; Fri, 03 Mar 2023 05:18:47 -0800 (PST) X-Google-Smtp-Source: AK7set9lvlkzgh29NJx71lNZ23M4VaLsIVdKsd03A9WtMjUPpV7Xw4jP6n8eNfCWf489fzweCw8bCA== X-Received: by 2002:a05:600c:1d1a:b0:3eb:3e75:5d6e with SMTP id l26-20020a05600c1d1a00b003eb3e755d6emr1186400wms.18.1677849527428; Fri, 03 Mar 2023 05:18:47 -0800 (PST) Date: Fri, 3 Mar 2023 08:18:43 -0500 From: "Michael S. Tsirkin" To: Stefan Hajnoczi 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: <20230303081515-mutt-send-email-mst@kernel.org> References: <910b3607a5f255134d30b3e1233e564f564eafb8.1677761896.git.mst@redhat.com> <20230302201011.GB2554028@fedora> <20230302185214-mutt-send-email-mst@kernel.org> <20230303131337.GA2866370@fedora> MIME-Version: 1.0 In-Reply-To: <20230303131337.GA2866370@fedora> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: [virtio-dev] Re: [PATCH v10 03/10] admin: introduce group administration commands On Fri, Mar 03, 2023 at 08:13:37AM -0500, Stefan Hajnoczi wrote: > 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. > > > > > > > > Following patches will introduce specific commands and an interface for > > > > submitting these commands to the owner. > > > > > > > > Signed-off-by: Max Gurtovoy > > > > Signed-off-by: Michael S. Tsirkin > > > > --- > > > > admin.tex | 108 +++++++++++++++++++++++++++++++++++++++++++++++ > > > > introduction.tex | 3 ++ > > > > 2 files changed, 111 insertions(+) > > > > > > > > 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 Facilities of a Virtio Device / Device g > > > > PCI transport (see \ref{sec:Virtio Transport Options / Virtio Over PCI Bus}). > > > > \end{description} > > > > > > > > +\subsection{Group administration commands}\label{sec:Basic Facilities of a Virtio Device / Device groups / Group administration commands} > > > > > > > > +The driver sends group administration commands to the owner device of > > > > > > 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. > > > > 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 set 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} > > > > > > 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. > > > > 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? I am not good in predicting future ... > 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) What if I just write it like this: > > > > +\hline \hline > > > > +0x0000 - 0x7FFF & - & commands using struct virtio_admin_cmd \\ > > > > +\hline > > > > +0x8000 - 0xFFFF & - & Reserved for future commands (possibly using a different structure) \\ will this address the comment? > > > > + > > > > +The \field{group_type} specifies the group type identifier. > > > > +The \field{group_member_id} specifies the member identifier within the 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_qialifier} > > > > > > s/qialifier/qualifier/ > > > > > > > +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} values: > > > > > > s/qialifier/qualifier/ > > > > > > > +\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 invalid \field{opcode} \\ > > > > +\hline > > > > +0x02 & VIRTIO_ADMIN_STATUS_Q_INVALID_FIELD & unsupported or invalid field within \field{command_specific_data} \\ > > > > +\hline > > > > +0x03 & VIRTIO_ADMIN_STATUS_Q_INVALID_GROUP & unsupported or invalid \field{group_type} \\ > > > > +\hline > > > > +0x04 & VIRTIO_ADMIN_STATUS_Q_INVALID_MEMBER & unsupported or invalid \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. > > > > > > On more thing: > > > > > > Does the owner device see commands in order but may complete them in any > > > order? > > > > > > 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. > > > > 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 --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org