Re: [PATCH RFC v7 1/8] Introduce device group

[Jason Wang <jasowang@redhat.com>]

On Sat, Aug 13, 2022 at 1:19 AM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> From: Max Gurtovoy <mgurtovoy@nvidia.com>
>
> Each device group has a type. For now, define one initial type of device
> groups: SR-IOV type.
>
> SR-IOV type - A virtio PCI SR-IOV physical function (PF) and its
> PCI SR-IOV virtual functions (VFs). This group may contain one or more
> virtio devices.
>
> Each device group has a unique identifier. This identifier is the group
> identifier.
>
> Each device within a device group has a unique identifier. This identifier
> is the group member identifier.
>
> Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  admin.tex   | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
>  content.tex |  2 ++
>  2 files changed, 51 insertions(+)
>  create mode 100644 admin.tex
>
> diff --git a/admin.tex b/admin.tex
> new file mode 100644
> index 0000000..6e9434a
> --- /dev/null
> +++ b/admin.tex
> @@ -0,0 +1,49 @@
> +\section{Device groups}\label{sec:Basic Facilities of a Virtio Device / Device groups}
> +
> +It is occasionally useful to have a device control a group of
> +other devices. Terminology used in such cases:
> +
> +\begin{description}
> +\item[Device group]
> +        or just group, includes zero or more devices.
> +\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.
> +\item[Member identifier]
> +        each member has this indentifier, unique within the group

Typo, should be "identifier"

> +       and used to address it through the parent device.
> +\item[Group type]
> +       specifies what kind of member devices there are in a
> +       group, how is the member identifier intepreted

"interpreted"

> +       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.
> +\end{description}
> +
> +A single group type is currently specified:
> +\begin{description}
> +\item[SR-IOV group type]
> +This device group has a PCI Single Root I/O Virtualization
> +(SR-IOV) physical function (PF) device as a parent and includes
> +all its SR-IOV virtual functions (VFs) as members (see
> +\hyperref[intro:PCIe]{[PCIe]}).
> +
> +The PF device itself is not a member of the group.
> +
> +At most one group of this type can exist per PF, and
> +the group identifier for a group of this type is always 0x1.
> +
> +A member identifier for this group can have a value 0x1 to 0xFFFF
> +and equals the SR-IOV VF number of the member device (see
> +\hyperref[intro:PCIe]{[PCIe]}).
> +
> +Both parent and member devices for this group type use the Virtio
> +PCI transport (see \ref{sec:Virtio Transport Options / Virtio Over PCI Bus}).
> +\end{description}

I wonder if it's better to reserve types as transport specific ones
and then we can move the above to the part of PCI transport.

Thanks

> +
> +
> diff --git a/content.tex b/content.tex
> index e863709..6e26dff 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -449,6 +449,8 @@ \section{Exporting Objects}\label{sec:Basic Facilities of a Virtio Device / Expo
>  types. It is RECOMMENDED that devices generate version 4
>  UUIDs as specified by \hyperref[intro:rfc4122]{[RFC4122]}.
>
> +\input{admin.tex}
> +
>  \chapter{General Initialization And Device Operation}\label{sec:General Initialization And Device Operation}
>
>  We start with an overview of device initialization, then expand on the
> --
> MST
>