[PATCH v10 00/10] Introduce device group and device management

From
David Edmondson <>
Date
2023-03-07T10:32:00+00:00
ID
Thread
[PATCH v10 00/10] Introduce device group and device management
"Michael S. Tsirkin" <> writes:
> 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
> +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

As before, this formatting is potentially confusing. There should be a
difference between "value X has meaning Y" and "a range from X to Y".

> +
*/
> +
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}
> +
> +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}

"status_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:
> +\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.

Would it make sense to add some advisory text about alignment of the
fields after command_specific_data? It would be annoying if status,
status_qualifier, etc. were poorly aligned for a common hardware
implementation.
> diff --git a/introduction.tex b/introduction.tex
> index 287c5fc..0d849a9 100644
> --- a/introduction.tex
> +++ b/introduction.tex
> @@ -68,6 +68,9 @@ \section{Normative References}\label{sec:Normative References}
>  	\phantomsection\label{intro:FUSE}\textbf{[FUSE]} &
>  	Linux FUSE interface,
>  	\newline\url{https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/fuse.h}\\
> +	\phantomsection\label{intro:errno}\textbf{[errno]} &
> +	Linux error names and numbers,
> +	\newline\url{https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/uapi/asm-generic/errno-base.h}\\
>
\phantomsection\label{intro:eMMC}\textbf{[eMMC]} &
>
eMMC Electrical Standard (5.1), JESD84-B51,
>
\newline\url{http://www.jedec.org/sites/default/files/docs/JESD84-B51.pdf}\\
> --
> MST
>
>
>

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