Re: [virtio-comment] [PATCH v10] virtio-net: support the virtqueue coalescing moderation

[Heng Qi <hengqi@linux.alibaba.com>]

å 2023/3/7 äå6:57, Michael S. Tsirkin åé:
> On Thu, Mar 02, 2023 at 11:36:18AM +0000, David Edmondson wrote:
> > > +                                        for an enabled transmit/receive virtqueue whose number is \field{vqn}.
> > Should this now be "whose index is \field{vqn}"?
> Ugh.  I guess we'll have to fix the number/index mess in the spec
> first. Parav you said you are looking into it?



# Where virtqueue number and virtqueue index are used.
 1. In the Virtqueue Configuration Section, use the virtqueue index: 
"Write the **virtqueue index** (first queue is 0) to queue_select."
 2. Both descriptions are used separately in the Notification Section.
ÂÂÂÂÂ 2.1 Here vqn is called virtqueue index:
ÂÂÂÂÂÂÂÂÂÂÂ "When VIRTIO_F_NOTIFICATION_DATA has not been negotiated, 
the driver sends an available buffer notification
ÂÂÂÂÂÂÂÂÂÂÂÂÂ to the device by writing the **16-bit virtqueue index** 
of this virtqueue to the Queue Notify address.
ÂÂÂÂÂÂÂÂÂÂÂÂÂ ...

ÂÂÂÂÂÂÂÂÂÂÂÂÂ le32 {
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ vqn: 16;
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ next_off : 15;
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ next_wrap: 1;
ÂÂÂÂÂÂÂÂÂÂÂÂ };
ÂÂÂÂÂÂÂÂÂÂÂÂ ...

ÂÂÂÂÂÂÂÂÂÂÂÂ If VIRTIO_F_NOTIFICATION_DATA has not been negotiated, the 
driver MUST use the queue_notify_data value instead of the **virtqueue 
index**."

ÂÂÂÂÂ 2.2 Here vqn is called virtqueue number:
ÂÂÂÂÂÂÂÂÂÂÂ "When VIRTIO_F_NOTIFICATION_DATA has not been negotiated, 
the Notification data contains the **Virtqueue number**.
ÂÂÂÂÂÂÂÂÂÂÂ ...

ÂÂÂÂÂÂÂÂÂÂÂ be32 {
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ vqn: 16;
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ next_off : 15;
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ next_wrap: 1;
ÂÂÂÂÂÂÂÂÂÂÂÂ };
ÂÂÂÂÂÂÂÂÂÂÂ ...

ÂÂÂÂÂÂÂÂÂÂÂ When VIRTIO_F_NOTIFICATION_DATA has not been negotiated, 
this notification involves sending the **virtqueue number** to the 
device (method depending on the transport).
ÂÂÂÂÂÂÂÂÂÂÂ ...

ÂÂÂÂÂÂÂÂÂÂÂ vqn -- **VQ number** to be notified."

# 0-based index and 0-based number are used respectively in the RSS Section:
1. "Field unclassified_queue contains the **0-based index** of the 
receive virtqueue to place unclassified packets in. Index 0 corresponds 
to receiveq1."
2. "use the result as the index in the indirection table to get 
**0-based number** of destination receiveq (value of 0 corresponds to 
receiveq1)."



\field{vqn} has been called '0-based virtqueue index' or '0-based 
virtqueue number',
I think both seem to be friendly to readers, so what are your options?

Thanks.

>