On Wednesday, 2023-02-15 at 02:53:34 +02, Max Gurtovoy wrote:
> On 13/02/2023 14:21, David Edmondson wrote:
>> On Thursday, 2023-02-09 at 07:13:48 -05, Michael S. Tsirkin wrote:
>>> @@ -1031,6 +1035,19 @@ \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}) inclusive serve as administration
>>> + virtqueues.
>>> + Thus the number of administration virtqueues equals
>>> + (\field{admin_queue_num} + 1).
>> Really the number of queues is "admin_queue_num + 1"?
>> That seems ... odd.
>
> It's not odd if we'll mention that this is a zero based value.
> MST, can you add it please for the next version ?
The field is called ...num, which makes it seem like a count of things,
when in reality it's the highest index. Perhaps the name could more
accurately reflect the intent?
>
>>
>>> + 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}
>>> @@ -1117,6 +1134,14 @@ \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} inclusive.
>>> +The driver MAY configure less administration virtqueues than
>>> +supported by the device.
>>> +
>>>
\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
>>> @@ -7684,6 +7709,15 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits}
>>>
\item[VIRTIO_F_ADMIN_VQ(41)] This feature indicates that the
>>> device exposes one or more
>>>
administration virtqueues.
>>> + 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 and is reserved for future use for
>>> + devices using other transports (see
>>> + \ref{drivernormative:Basic Facilities of a Virtio Device / Feature Bits}
>>> + and
>>> + \ref{devicenormative:Basic Facilities of a Virtio Device / Feature Bits} for
>>> + handling features reserved for future use.
>>>
\end{description}
--
Stop the music and go home.
