Re: [virtio-comment] [PATCH v4 2/8] transport-pci: Refer to the vq by its number

[Max Gurtovoy <mgurtovoy@nvidia.com>]

On 22/03/2023 23:52, Parav Pandit wrote:
> Currently specification uses virtqueue index and
> number interchangeably to refer to the virtqueue.
>
> Instead refer to it by its number.
>
> This patch is on top of [1].
>
> [1] https://lists.oasis-open.org/archives/virtio-dev/202302/msg00527.html
>
> Fixes: https://github.com/oasis-tcs/virtio-spec/issues/163
> Reviewed-by: Jiri Pirko <jiri@nvidia.com>
> Signed-off-by: Parav Pandit <parav@nvidia.com>
> ---
> changelog:
> v2->v3:
> - addressed comments from Michael
> - changed vqn to virtqueue number in the Note
> - refer to vqn field instead of virtqueue number
> ---
>   content.tex       |  2 +-
>   transport-pci.tex | 14 ++++++++------
>   2 files changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/content.tex b/content.tex
> index 1ab7794..0f634ac 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -321,7 +321,7 @@ \section{Virtqueues}\label{sec:Basic Facilities of a Virtio Device / Virtqueues}
>   VIRTIO_F_IN_ORDER feature. If negotiated, this knowledge
>   might allow optimizations or simplify driver and/or device code.
>   
> -Each virtqueue is identified as vq number or also referred
> +Each virtqueue is identified by a vq number or also referred
>   to as a virtqueue number; vq number range is from 0 to 65535.
>   

Please squash this to patch 1/8 were you introduced this line.



>   Each virtqueue can consist of up to 3 parts:
> diff --git a/transport-pci.tex b/transport-pci.tex
> index b07a822..044c085 100644
> --- a/transport-pci.tex
> +++ b/transport-pci.tex
> @@ -390,13 +390,15 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport
>   
>   \item[\field{queue_notify_data}]
>           This field exists only if VIRTIO_F_NOTIF_CONFIG_DATA has been negotiated.
> -        The driver will use this value to put it in the 'virtqueue number' field
> -        in the available buffer notification structure.
> +        The driver will use this value to put it in the field
> +        \field{vqn} in the available buffer notification
> +        structure.

why do you add new lines here and bellow ?

>           See section \ref{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Available Buffer Notifications}.
>           \begin{note}
>           This field provides the device with flexibility to determine how virtqueues
>           will be referred to in available buffer notifications.
> -        In a trivial case the device can set \field{queue_notify_data}=vqn. Some devices
> +        In a trivial case the device can set
> +        \field{queue_notify_data}=vq number. Some devices
>           may benefit from providing another value, for example an internal virtqueue
>           identifier, or an internal offset related to the virtqueue number.
>           \end{note}
> @@ -1005,7 +1007,7 @@ \subsubsection{Device Initialization}\label{sec:Virtio Transport Options / Virti
>   The driver typically does this as follows, for each virtqueue a device has:
>   
>   \begin{enumerate}
> -\item Write the virtqueue index (first queue is 0) to \field{queue_select}.
> +\item Write the virtqueue number (first queue is 0) to \field{queue_select}.
>   
>   \item Read the virtqueue size from \field{queue_size}. This controls how big the virtqueue is
>     (see \ref{sec:Basic Facilities of a Virtio Device / Virtqueues}~\nameref{sec:Basic Facilities of a Virtio Device / Virtqueues}). If this field is 0, the virtqueue does not exist.
> @@ -1035,7 +1037,7 @@ \subsubsection{Available Buffer Notifications}\label{sec:Virtio Transport Option
>   
>   When VIRTIO_F_NOTIFICATION_DATA has not been negotiated,
>   the driver sends an available buffer notification to the device by writing
> -the 16-bit virtqueue index
> +the 16-bit virtqueue number
>   of this virtqueue to the Queue Notify address.
>   
>   When VIRTIO_F_NOTIFICATION_DATA has been negotiated,
> @@ -1053,7 +1055,7 @@ \subsubsection{Available Buffer Notifications}\label{sec:Virtio Transport Option
>   If VIRTIO_F_NOTIF_CONFIG_DATA has been negotiated:
>   \begin{itemize}
>   \item If VIRTIO_F_NOTIFICATION_DATA has not been negotiated, the driver MUST use the
> -\field{queue_notify_data} value instead of the virtqueue index.
> +\field{queue_notify_data} value instead of the virtqueue number.
>   \item If VIRTIO_F_NOTIFICATION_DATA has been negotiated, the driver MUST set the
>   \field{vqn} field to the \field{queue_notify_data} value.
>   \end{itemize}

In general, after fixing the above minor comments - looks good.

Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>