From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Sun, 31 Jul 2022 16:38:38 -0400 From: "Michael S. Tsirkin" Subject: Re: [PATCH v6 1/5] Introduce device group Message-ID: <20220731163029-mutt-send-email-mst@kernel.org> References: <20220731154354.15698-1-mgurtovoy@nvidia.com> <20220731154354.15698-2-mgurtovoy@nvidia.com> MIME-Version: 1.0 In-Reply-To: <20220731154354.15698-2-mgurtovoy@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline To: Max Gurtovoy Cc: jasowang@redhat.com, virtio-comment@lists.oasis-open.org, cohuck@redhat.com, virtio-dev@lists.oasis-open.org, oren@nvidia.com, parav@nvidia.com, shahafs@nvidia.com, aadam@redhat.com, virtio@lists.oasis-open.org, eperezma@redhat.com List-ID: On Sun, Jul 31, 2022 at 06:43:50PM +0300, Max Gurtovoy wrote: > Each device group has a type. For now, define 2 initial types of device > groups: Self type and SR-IOV type. > > Self type - A group that has a single virtio device as a member. > > 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 (group_id). > > Each device within a device group has a unique identifier. This identifier > is the group member identifier (group_member_id). > > Reviewed-by: Parav Pandit > Signed-off-by: Max Gurtovoy This looks good to me. Minor corrections below. > --- > introduction.tex | 24 ++++++++++++++++++++++++ > 1 file changed, 24 insertions(+) > > diff --git a/introduction.tex b/introduction.tex > index aa9ec1b..e8bde45 100644 > --- a/introduction.tex > +++ b/introduction.tex > @@ -156,6 +156,30 @@ \subsection{Transition from earlier specification drafts}\label{sec:Transition f > sections tagged "Legacy Interface" in the section title. > These highlight the changes made since the earlier drafts. > > +\subsection{Device group}\label{sec:Introduction / Terminology / Device group} > + Maybe an introductory sentence. "It is occasionally useful to manage multiple virtio devices as a group." > +A device group includes one or more virtio devices. Each device group has a unique group identifier (group_id). Wait a second. Is this true? To me it looks like group identifier should actually be group type identifier. And it's not unique. This rename will of course ripple to follow up patches. > +A device can be a member of one or more device groups. > +A device within a group is identified by a unique group member identifier (group_member_id). group_member_id and group_id seem unused here. Drop? > +The scope of the group member identifier is within the group. In other words, two device groups can have overlap group member identifiers. > +A group member identifier is a 64-bit value in range of 0x0 - 0xFFFFFFFFFFFFFFF0. in the range between 0x0 and 0xFFFFFFFFFFFFFFF0 inclusive. > +A special group member identifier value of 0xFFFFFFFFFFFFFFFF refers to all the devices in a device group. all devices in the device group. > + > +The supported device groups are: > +\begin{enumerate} > +\item Self type (group identifier = 0) - this group has only one device in the group. Each virtio device is a member of at least one device group, the Self type group. > +For this group type, the device is identified by group member identifier of 0. by a group member identifier > + > +\item SR-IOV type (group identifier = 1) - this group includes a virtio PCI SR-IOV physical function (PF) and all its virtual functions (VFs). > +For this group type, the PF device has group member identifier of 0. Each VF group member identifier equals the PCI VF number according to the PCI Express Base Specification > +(Single Root I/O Virtualization and Sharing chapter). Devices that are members in this group use the Virtio PCI transport (for more details see \ref{sec:Virtio Transport Options / Virtio Over PCI Bus}). > +\end{enumerate} > + > +\begin{note} > + The same device can be identified by different identifiers within different groups. For example, A virtual function device has a group > + member identifier equals to 0 within Self type group and a group member identifier equals to VF number (e.g 4) within SR-IOV type group. > +\end{note} > + > \section{Structure Specifications}\label{sec:Structure Specifications} > > Many device and driver in-memory structure layouts are documented using > -- > 2.21.0