virtio — archive

[Parav Pandit <parav@nvidia.com>]

On 4/24/2023 12:44 PM, Michael S. Tsirkin wrote: > Each device group has a type. For now, define one initial group type: > > SR-IOV type - PCI SR-IOV virtual functions (VFs) of a given > PCI SR-IOV physical function (PF). This group may contain zero or more > virtio devices according to NumVFs configured. > > Each device within a group has a unique identifier. This identifier > is the group member identifier. > > Note: one can argue both ways whether the new device group handling > functionality (this and following patches) is closer > to a new device type or a new transport type. > > However, it's expected that we will add more features in the near > future. To facilitate this as much as possible of the text is located in > the new admin chapter. > > Effort was made to minimize transport-specific text. > > There's a bit of duplication with 0x1 repeated twice and > no special section for group type identifiers. > It seems ok to defer adding these until we have more group > types. > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> > --- > changes in v12: > stefan's ack > minor commit log tweaks, Parav > use neutral tone, Parav > > changes in v11: > dropped Max's S.O.B. > dropped an unmatched ) as reported by Parav > document that member id is 1 to numvfs > document that vf enable must be set (will also be reflected in > the conformance section) > document that we deferred generalizing text as requested by Parav - > I think we can do it later > minor wording fixes to address comments by David > add concepts of owner and member driver. unused currently > but will come in handy later, as suggested by Stefan > --- > admin.tex | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++ > content.tex | 2 ++ > 2 files changed, 65 insertions(+) > create mode 100644 admin.tex > > diff --git a/admin.tex b/admin.tex > new file mode 100644 > index 0000000..05d506a > --- /dev/null > +++ b/admin.tex > @@ -0,0 +1,63 @@ > +\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[Owner device] > + or owner, the device controlling the group. > +\item[Member device] > + a device within a group. The owner device itself is not > + a member of the group. > +\item[Member identifier] > + each member has this identifier, unique within the group > + and used to address it through the owner device. > +\item[Group type identifier] > + specifies what kind of member devices there are in a > + group, how the member identifier is interpreted > + and what kind of control the owner has. > + A given owner can control multiple groups > + of different types but only a single group of a given type, > + thus the type and the owner together identify the group. > + \footnote{Even though some group types only support > + specific transports, group type identifiers > + are global rather than transport-specific - > + a flood of new group types is not expected.} > +\end{description} > + > +\begin{note} > +Each device only has a single driver, thus for the purposes of > +this section, "the driver" is usually unambiguous and refers to > +the driver of the owner device. When there's ambiguity, "owner > +driver" refers to the driver of the owner device, while "member > +driver" refers to the driver of a member device. > +\end{note} > + > +The following group types, and their identifiers, are currently specified: > +\begin{description} > +\item[SR-IOV group type (0x1)] > +This device group has a PCI Single Root I/O Virtualization > +(SR-IOV) physical function (PF) device as the owner 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. > + > +The group type identifier for this group is 0x1. > + > +A member identifier for this group can have a value from 0x1 to > +\field{NumVFs} as specified in the > +SR-IOV Extended Capability of the owner device > +and equals the SR-IOV VF number of the member device; > +the group only exists when the \field{VF Enable} bit > +in the SR-IOV Control Register within the > +SR-IOV Extended Capability of the owner device is set > +(see \hyperref[intro:PCIe]{[PCIe]}). > + > +Both owner and member devices for this group type use the Virtio > +PCI transport (see \ref{sec:Virtio Transport Options / Virtio Over PCI Bus}). > +\end{description} > + > + Please take care to remove above two empty lines when you merge these changes. We don't need v13 for it. :) > diff --git a/content.tex b/content.tex > index 8098988..04592fb 100644 > --- a/content.tex > +++ b/content.tex > @@ -493,6 +493,8 @@ \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 Reviewed-by: Parav Pandit <parav@nvidia.com>