Re: [PATCH RFC v7 4/8] Add admin_queue_index register to PCI common configuration structure

[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>
>
> This new register will be used for querying the index of the admin
> virtqueue of a virtio device. To configure, reset or enable the admin
> virtqueue, the driver should follow existing queue configuration/setup
> sequence.
>
> Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  content.tex | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>
> diff --git a/content.tex b/content.tex
> index 6ce1c07..297cb4a 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -904,6 +904,9 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport
>          le64 queue_device;              /* read-write */
>          le16 queue_notify_data;         /* read-only for driver */
>          le16 queue_reset;               /* read-write */
> +
> +        /* About the administration virtqueue. */
> +        le16 admin_queue_index;         /* read-only for driver */

Is there a chance that we may have multiple admin virtqueues?

Thanks


>  };
>  \end{lstlisting}
>
> @@ -989,6 +992,10 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport
>          This field exists only if VIRTIO_F_RING_RESET has been
>          negotiated. (see \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}).
>
> +\item[\field{admin_queue_index}]
> +        The device uses this to report the index of the administration virtqueue.
> +        This field is valid only if VIRTIO_F_ADMIN_VQ has been negotiated.
> +
>  \end{description}
>
>  \devicenormative{\paragraph}{Common configuration structure layout}{Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Common configuration structure layout}
> @@ -1075,6 +1082,9 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport
>  were used before the queue reset.
>  (see \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}).
>
> +If VIRTIO_F_ADMIN_VQ has been negotiated, the driver MUST
> +configure the administration virtqueue using the value of \field{admin_queue_index}.
> +
>  \subsubsection{Notification structure layout}\label{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Notification capability}
>
>  The notification location is found using the VIRTIO_PCI_CAP_NOTIFY_CFG
> @@ -6947,6 +6957,10 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits}
>    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.
> +  At the moment this feature is only supported for devices using
> +  \ref{sec:Virtio Transport Options / Virtio Over PCI
> +         Bus}~\nameref{sec:Virtio Transport Options / Virtio Over PCI Bus}
> +         as the transport.
>
>  \end{description}
>
> --
> MST
>