From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 9 Feb 2023 10:13:46 -0500 From: "Michael S. Tsirkin" Subject: Re: [virtio-comment] [PATCH v10 02/10] admin: introduce device group and related concepts Message-ID: <20230209100903-mutt-send-email-mst@kernel.org> References: <20230209121221.15118-1-mst@redhat.com> <20230209121221.15118-3-mst@redhat.com> MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=us-ascii Content-Disposition: inline To: David Edmondson Cc: virtio-dev@lists.oasis-open.org, jasowang@redhat.com, cohuck@redhat.com, sgarzare@redhat.com, stefanha@redhat.com, nrupal.jani@intel.com, Piotr.Uminski@intel.com, hang.yuan@intel.com, virtio@lists.oasis-open.org, Zhu Lingshan , pasic@linux.ibm.com, Shahaf Shuler , Parav Pandit , Max Gurtovoy , virtio-comment@lists.oasis-open.org List-ID: On Thu, Feb 09, 2023 at 03:00:58PM +0000, David Edmondson wrote: > > On Thursday, 2023-02-09 at 07:13:36 -05, Michael S. Tsirkin wrote: > > Each device group has a type. For now, define one initial group: > > > > SR-IOV type - PCI SR-IOV virtual functions (VFs) of a given > > PCI SR-IOV physical function (PF). This group may contain one or more > > virtio devices. > > The specification says zero or more generally and nothing to refine that > for SR-IOV groups. Well it says: (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]}). how can that be zero? > > > > 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, I expect 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. > > > > I did my best to minimize transport-specific text. > > > > Signed-off-by: Max Gurtovoy > > Signed-off-by: Michael S. Tsirkin > > --- > > 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..2bc7322 > > --- /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[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 is the member identifier is interpreted > > + and what kind of control the owner has. > > + A given owner can control 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 - > > + we don't expect a flood of new group types.} > > +\end{description} > > + > > +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 0x1 to 0xFFFF > > +and equals the SR-IOV VF number of the member device (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} > > + > > + > > diff --git a/content.tex b/content.tex > > index 0c2d917..ffe45c4 100644 > > --- a/content.tex > > +++ b/content.tex > > @@ -491,6 +491,8 @@ \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 > -- > Tell her I'll be waiting, in the usual place.