From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Sun, 31 Jul 2022 17:00:35 -0400 From: "Michael S. Tsirkin" Subject: Re: [PATCH v6 3/5] Introduce virtio admin virtqueue Message-ID: <20220731170009-mutt-send-email-mst@kernel.org> References: <20220731154354.15698-1-mgurtovoy@nvidia.com> <20220731154354.15698-4-mgurtovoy@nvidia.com> MIME-Version: 1.0 In-Reply-To: <20220731154354.15698-4-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 06:43:52PM +0300, Max Gurtovoy wrote: > In one of the many use cases a user wants to manipulate features and > configuration of the virtio devices regardless of the device type > (net/block/console). For that the admin command set introduced. The > admin virtqueue will be the first management interface to issue admin > commands. > > Currently virtio specification defines control virtqueue to manipulate > features and configuration of the device it operates on. However, > control virtqueue commands are device type specific, which makes it very > difficult to extend for device agnostic commands. > > To support this requirement in elegant way, this patch introduces a new > admin virtqueue interface. > > Manipulate features via admin virtqueue is asynchronous, scalable, easy > to extend and doesn't require additional and expensive on-die resources > to be allocated for every new feature that will be added in the future. > > Reviewed-by: Parav Pandit > Signed-off-by: Max Gurtovoy > --- > admin.tex | 12 ++++++++++++ > content.tex | 6 ++++-- > 2 files changed, 16 insertions(+), 2 deletions(-) > > diff --git a/admin.tex b/admin.tex > index d14f8f7..26ac60e 100644 > --- a/admin.tex > +++ b/admin.tex > @@ -80,3 +80,15 @@ \section{Administration command set}\label{sec:Basic Facilities of a Virtio Devi > 8000h - FFFFh & Reserved \\ > \hline > \end{tabular} > + > +\section{Admin Virtqueues}\label{sec:Basic Facilities of a Virtio Device / Admin Virtqueues} > + > +An admin virtqueue is a management interface of a device that can be used to send administrative > +commands (see \ref{sec:Basic Facilities of a Virtio Device / Administration command set}) to manipulate > +various features of the device and/or to manipulate various features, if possible, of another device. > + > +An admin virtqueue exists for a certain device if VIRTIO_F_ADMIN_VQ feature is > +negotiated. The index of the admin virtqueue is exposed by the device in a > +transport specific manner. > + > +If VIRTIO_F_ADMIN_VQ has been negotiated, the driver will use the admin virtqueue to send all admin commands. > diff --git a/content.tex b/content.tex > index caab298..c15423e 100644 > --- a/content.tex > +++ b/content.tex > @@ -99,10 +99,10 @@ \section{Feature Bits}\label{sec:Basic Facilities of a Virtio Device / Feature B > \begin{description} > \item[0 to 23, and 50 to 127] Feature bits for the specific device type > > -\item[24 to 40] Feature bits reserved for extensions to the queue and > +\item[24 to 41] Feature bits reserved for extensions to the queue and > feature negotiation mechanisms > > -\item[41 to 49, and 128 and above] Feature bits reserved for future extensions. > +\item[42 to 49, and 128 and above] Feature bits reserved for future extensions. > \end{description} > > \begin{note} > @@ -6841,6 +6841,8 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits} > that the driver can reset a queue individually. > See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}. > > + \item[VIRTIO_F_ADMIN_VQ (41)] This feature indicates that an administration virtqueue is supported. mention here that index is in transport specific manner too? > + > \end{description} > > \drivernormative{\section}{Reserved Feature Bits}{Reserved Feature Bits} > -- > 2.21.0