[virtio-dev] Re: [PATCH v11 05/10] pci: add admin vq registers to virtio over pci

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Mon, Apr 03, 2023 at 11:03:29AM -0400, Michael S. Tsirkin wrote:
> @@ -1033,6 +1037,19 @@ \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 first administration virtqueue.
> +        This field is valid only if VIRTIO_F_ADMIN_VQ has been negotiated.
> +\item[\field{admin_queue_num}]
> +	The device uses this to report the number of the
> +	supported administration virtqueues.
> +	Virtqueues with index
> +	between \field{admin_queue_index} and (\field{admin_queue_index} +
> +	\field{admin_queue_num} - 1) inclusive serve as administration
> +	virtqueues.
> +	The value 0 indicates no supported administration virtqueues.
> +	This field is valid only if VIRTIO_F_ADMIN_VQ has been
> +	negotiated.
>  \end{description}

Maybe add a device-normative statement that [admin_queue_index,
admin_queue_index + admin_queue_num) must be located after
device-specific virtqueues?

That would remind implementers that the device-specific virtqueue layout
needs to be followed and cannot be modified by the presence of
Administration Virtqueues.

>  \devicenormative{\paragraph}{Common configuration structure layout}{Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Common configuration structure layout}
> @@ -1119,6 +1136,14 @@ \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, and if the driver
> +configures any administration virtqueues, the driver MUST
> +configure the administration virtqueues using the index
> +in the range \field{admin_queue_index} to
> +\field{admin_queue_index} + \field{admin_queue_num} - 1 inclusive.
> +The driver MAY configure less administration virtqueues than

s/less/fewer/

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