Re: [PATCH v9 03/10] admin: introduce group administration commands

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Nov 24, 2022 at 01:52:41PM +0800, Jason Wang wrote:
> On Thu, Nov 24, 2022 at 5:08 AM Michael S. Tsirkin <mst@redhat.com> 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 <mgurtovoy@nvidia.com>
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> >  admin.tex | 98 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 98 insertions(+)
> >
> > diff --git a/admin.tex b/admin.tex
> > index 6ebdd05..1dca136 100644
> > --- a/admin.tex
> > +++ b/admin.tex
> > @@ -42,4 +42,102 @@ \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}
> >
> > +Group administration commands can be issued through an owner
> > +device to control member devices of a group.  This mechanism can
> > +be used, for example, to configure a member device before it is
> > +initialized by its driver.
> 
> This excludes any possible runtime configuration, is this intended?

No idea - what kind of runtime configuration are you talking about?
This explicitly says "to configure a member device" and that's
certainly at runtime.


> 
> > +
> > +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}.
> > +
> > +As a rule, 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.
> 
> So this means there's no way for having a group specific adminq? E.g
> one queue for SR-IOV and another for SIOV.
> 
> > +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 Linux names and error numbers:
> 
> I may miss something but I don't see how it matches Linux error numbers.


include/uapi/asm-generic/errno-base.h:#define   EINVAL          22      /* Invalid argument */


> Thanks
> 
> > +
> > +\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}
> > +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_MEM    & unsupported or invalid \field{group_member_id} \\
> > +\hline
> > +0x05-0xFFFF   & -    & reserved for future use \\
> > +\hline
> > +\end{tabular}
> > --
> > MST
> >