On Fri, Mar 03, 2023 at 08:18:43AM -0500, Michael S. Tsirkin wrote:
> 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 <mgurto...@nvidia.com>
> > > > > Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
> > > > > ---
> > > > > 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?Yes, thanks. Stefan
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