On Thu, Aug 18, 2022 at 04:46:45PM +0800, Jason Wang wrote:
> On Sat, Aug 13, 2022 at 1:19 AM Michael S. Tsirkin <[email protected]> wrote:
> >
> > From: Max Gurtovoy <[email protected]>
> >
> > These commands are used for essential administrative and management
> > operations.
> >
> > Following patches will introduce an interface for submitting these
> > commands to the device.
> >
> > Signed-off-by: Max Gurtovoy <[email protected]>
> > Signed-off-by: Michael S. Tsirkin <[email protected]>
> > ---
> > admin.tex | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
> > 1 file changed, 94 insertions(+), 5 deletions(-)
> >
> > diff --git a/admin.tex b/admin.tex
> > index 6e9434a..4840dd4 100644
> > --- a/admin.tex
> > +++ b/admin.tex
> > @@ -9,8 +9,10 @@ \section{Device groups}\label{sec:Basic Facilities of a
> > Virtio Device / Device g
> > \item[Parent device]
> > or parent, the device controlling the group.
> > \item[Member device]
> > - a device within a group. Parent device itself may, or may
> > - not be a member of the group.
> > + a device within a group. Parent device itself is not
> > + a member of the group. In the future it is envisoned that
> > + new group types may be introduced where the parent
> > + device is a member of the group.
>
> This part should go with patch 1?
>
> > \item[Member identifier]
> > each member has this indentifier, unique within the group
> > and used to address it through the parent device.
> > @@ -20,9 +22,10 @@ \section{Device groups}\label{sec:Basic Facilities of a
> > Virtio Device / Device g
> > and what kind of control does the parent have.
> > \item[Group identifier]
> > each group has this identifier, unique within the parent device.
> > - this specifies the group type and possibly selects the
> > - group if multiple groups of the same type can be controlled by the
> > same
> > - parent device.
> > + This specifies the group type. In the future it is
> > + envisoned that new group types will be introduced where the group
> > + identifier also selects the group if multiple groups of the same
> > + type can be controlled by the same parent device.
> > \end{description}
> >
> > A single group type is currently specified:
> > @@ -46,4 +49,90 @@ \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 / Group administration commands}
> > +
> > +Group administration commands can be issued through a parent
> > +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.
> > +
> > +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_id;
>
> I wonder about the implication of this field. Does it mean:
>
> 1) a single admin virtqueue that manage two group of VFs
>
> or
>
> 2) a single admin virtqueue that manages both VFs and SFs (then
> 'group_type' should be better?)
>
> If it's 1, the group id seems not sufficient. If it's 2, I wonder if
> it scales (using a single admin virtqueue to manage both VF and SF).
>
> Thanks
2 at the moment. Not sure I understand why wouldn't it scale. I don't
see a fundamental difference between 1 or 2 VQs. We are not going to be
adding 1000s of them,
> > + /* unused, reserved for future extensions */
> > + u8 reserved1[12];
> > + le64 group_member_id;
> > + u8 command_specific_data[];
> > +
> > + /* Device-writable part */
> > + u8 status;
> > + u8 command_specific_error;
> > + /* unused, reserved for future extensions */
> > + u8 reserved2[6];
> > + u8 command_specific_result[];
> > +};
> > +\end{lstlisting}
> > +
> > +For all commands, \field{opcode}, \field{group_id} and if
> > +necessary \field{group_member_id} and \field{command_specific_data} are
> > +set by the driver, and the parent device sets \field{status} and if
> > +needed \field{command_specific_error} 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 & Command Description \\
> > +\hline \hline
> > +0000h - 7FFFh & Group administration commands \\
> > +\hline
> > +8000h - FFFFh & Reserved \\
> > +\hline
> > +\end{tabular}
> > +
> > +The \field{group_id} specifies the device group.
> > +The \field{group_member_id} specifies the member device within the group.
> > +See section \ref{sec:Introduction / Terminology / Device group}
> > +for the definition of the group identifier and group member
> > +identifier.
> > +
> > +The following table describes possible \field{status} values:
> > +
> > +\begin{tabular}{|l|l|l|}
> > +\hline
> > +Status & Name & Description \\
> > +\hline \hline
> > +00h & VIRTIO_ADMIN_STATUS_OK & successful completion \\
> > +\hline
> > +01h & VIRTIO_ADMIN_STATUS_CS_ERR & command specific error \\
> > +\hline
> > +02h & VIRTIO_ADMIN_STATUS_OPCODE_UNSUPPORTED & unsupported or invalid
> > \field{opcode} \\
> > +\hline
> > +03h & VIRTIO_ADMIN_STATUS_INVALID_FIELD & invalid field within
> > command specific data \\
> > +\hline
> > +04h & VIRTIO_ADMIN_STATUS_INVALID_GROUP & invalid group identifier
> > was set \\
> > +\hline
> > +05h & VIRTIO_ADMIN_STATUS_INVALID_MEM & invalid group member
> > identifier was set \\
> > +\hline
> > +\end{tabular}
> > +
> > +The \field{command_specific_error} should be inspected by the driver only
> > if \field{status} is set to
> > +VIRTIO_ADMIN_STATUS_CS_ERR by the device. In this case, the
> > +contents of \field{command_specific_error}
> > +holds the command specific error. If \field{status} is not set to
> > VIRTIO_ADMIN_STATUS_CS_ERR, the
> > +\field{command_specific_error} value is undefined and should be ignored by
> > the driver.
> >
> > --
> > MST
> >
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