[virtio-dev] [PATCH v4] virtio-net: support reset queue

[virtio-dev] [PATCH v4] virtio-net: support reset queue

[Xuan Zhuo]

This patch defines some requirements for virtio-net to support reset
queues.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 content.tex | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/content.tex b/content.tex
index c6f116c..45751f4 100644
--- a/content.tex
+++ b/content.tex
@@ -4337,6 +4337,10 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi
 \field{virtqueue_pairs} once it has placed the
 VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET command in a used buffer.
 
+If the destination receive queue is in reset state(See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}),
+the device SHOULD re-select a different random queue. If all receive queues are
+in reset state, the device MUST drop the packet.
+
 \subparagraph{Legacy Interface: Automatic receive steering in multiqueue mode}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Automatic receive steering in multiqueue mode / Legacy Interface: Automatic receive steering in multiqueue mode}
 When using the legacy interface, transitional devices and drivers
 MUST format \field{virtqueue_pairs}
@@ -4425,6 +4429,7 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi
 \item Calculate the hash of the packet as defined in \ref{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets}.
 \item If the device did not calculate the hash for the specific packet, the device directs the packet to the receiveq specified by \field{unclassified_queue} of virtio_net_rss_config structure (value of 0 corresponds to receiveq1).
 \item Apply \field{indirection_table_mask} to the calculated hash and use the result as the index in the indirection table to get 0-based number of destination receiveq (value of 0 corresponds to receiveq1).
+\item If the destination receive queue is in reset state(See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}), the device MUST drop the packet.
 \end{itemize}
 
 \paragraph{Offloads State Configuration}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Offloads State Configuration}
-- 
2.31.0


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Re: [virtio-dev] [PATCH v4] virtio-net: support reset queue

[Xuan Zhuo]

On Tue, 22 Feb 2022 14:52:41 +0800, Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote:
> This patch defines some requirements for virtio-net to support reset
> queues.

Is there any problem with this?

Thanks.

>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> ---
>  content.tex | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/content.tex b/content.tex
> index c6f116c..45751f4 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -4337,6 +4337,10 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi
>  \field{virtqueue_pairs} once it has placed the
>  VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET command in a used buffer.
>
> +If the destination receive queue is in reset state(See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}),
> +the device SHOULD re-select a different random queue. If all receive queues are
> +in reset state, the device MUST drop the packet.
> +
>  \subparagraph{Legacy Interface: Automatic receive steering in multiqueue mode}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Automatic receive steering in multiqueue mode / Legacy Interface: Automatic receive steering in multiqueue mode}
>  When using the legacy interface, transitional devices and drivers
>  MUST format \field{virtqueue_pairs}
> @@ -4425,6 +4429,7 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi
>  \item Calculate the hash of the packet as defined in \ref{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets}.
>  \item If the device did not calculate the hash for the specific packet, the device directs the packet to the receiveq specified by \field{unclassified_queue} of virtio_net_rss_config structure (value of 0 corresponds to receiveq1).
>  \item Apply \field{indirection_table_mask} to the calculated hash and use the result as the index in the indirection table to get 0-based number of destination receiveq (value of 0 corresponds to receiveq1).
> +\item If the destination receive queue is in reset state(See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}), the device MUST drop the packet.
>  \end{itemize}
>
>  \paragraph{Offloads State Configuration}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Offloads State Configuration}
> --
> 2.31.0
>
>
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[virtio-dev] Re: [PATCH v4] virtio-net: support reset queue

[Jason Wang]

在 2022/2/22 14:52, Xuan Zhuo 写道:
> This patch defines some requirements for virtio-net to support reset
> queues.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> ---


Reviewed-by: Jason Wang <jasowang@redhat.com>


>   content.tex | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/content.tex b/content.tex
> index c6f116c..45751f4 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -4337,6 +4337,10 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi
>   \field{virtqueue_pairs} once it has placed the
>   VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET command in a used buffer.
>   
> +If the destination receive queue is in reset state(See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}),
> +the device SHOULD re-select a different random queue. If all receive queues are
> +in reset state, the device MUST drop the packet.
> +
>   \subparagraph{Legacy Interface: Automatic receive steering in multiqueue mode}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Automatic receive steering in multiqueue mode / Legacy Interface: Automatic receive steering in multiqueue mode}
>   When using the legacy interface, transitional devices and drivers
>   MUST format \field{virtqueue_pairs}
> @@ -4425,6 +4429,7 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi
>   \item Calculate the hash of the packet as defined in \ref{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets}.
>   \item If the device did not calculate the hash for the specific packet, the device directs the packet to the receiveq specified by \field{unclassified_queue} of virtio_net_rss_config structure (value of 0 corresponds to receiveq1).
>   \item Apply \field{indirection_table_mask} to the calculated hash and use the result as the index in the indirection table to get 0-based number of destination receiveq (value of 0 corresponds to receiveq1).
> +\item If the destination receive queue is in reset state(See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}), the device MUST drop the packet.
>   \end{itemize}
>   
>   \paragraph{Offloads State Configuration}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Offloads State Configuration}


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[virtio-dev] Re: [PATCH v4] virtio-net: support reset queue

[Michael S. Tsirkin]

On Tue, Feb 22, 2022 at 02:52:41PM +0800, Xuan Zhuo wrote:
> This patch defines some requirements for virtio-net to support reset
> queues.
> 
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>

Suggest creating a github issue documenting that it is not defined
what the behaviour is, so we rememeber to list this as a known issue
in 1.2.


> ---
>  content.tex | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/content.tex b/content.tex
> index c6f116c..45751f4 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -4337,6 +4337,10 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi
>  \field{virtqueue_pairs} once it has placed the
>  VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET command in a used buffer.
>  
> +If the destination receive queue is in reset state(See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}),

Should this be "a reset state"? Also, I do not see any definition of "reset state" in
the linked chapter. That chapter should really be cleaned up btw.

> +the device SHOULD re-select a different random queue.

different from what?

I suspect we want to move this:

When multiqueue is enabled by VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET command, the device MUST use automatic receive steering
based on packet flow. Programming of the receive steering
classificator is implicit. After the driver transmitted a packet of a
flow on transmitqX, the device SHOULD cause incoming packets for that flow to
be steered to receiveqX. For uni-directional protocols, or where
no packets have been transmitted yet, the device MAY steer a packet
to a random queue out of the specified receiveq1\ldots receiveqn.



to a conformance chapter, and be replaced with a general description
avoiding conformance keyworkds like MUST and SHOULD.


Generally, whenever we have conformance keywords out of conformance
clauses it's a bug and source of confusion at some point.


> If all receive queues are
> +in reset state, the device MUST drop the packet.
> +
>  \subparagraph{Legacy Interface: Automatic receive steering in multiqueue mode}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Automatic receive steering in multiqueue mode / Legacy Interface: Automatic receive steering in multiqueue mode}
>  When using the legacy interface, transitional devices and drivers
>  MUST format \field{virtqueue_pairs}
> @@ -4425,6 +4429,7 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi
>  \item Calculate the hash of the packet as defined in \ref{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets}.
>  \item If the device did not calculate the hash for the specific packet, the device directs the packet to the receiveq specified by \field{unclassified_queue} of virtio_net_rss_config structure (value of 0 corresponds to receiveq1).
>  \item Apply \field{indirection_table_mask} to the calculated hash and use the result as the index in the indirection table to get 0-based number of destination receiveq (value of 0 corresponds to receiveq1).
> +\item If the destination receive queue is in reset state(See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}), the device MUST drop the packet.
>  \end{itemize}
>  
>  \paragraph{Offloads State Configuration}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Offloads State Configuration}
> -- 
> 2.31.0


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[virtio-dev] Re: [PATCH v4] virtio-net: support reset queue

[Xuan Zhuo]

On Sun, 24 Apr 2022 02:53:46 -0400, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> On Tue, Feb 22, 2022 at 02:52:41PM +0800, Xuan Zhuo wrote:
> > This patch defines some requirements for virtio-net to support reset
> > queues.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
>
> Suggest creating a github issue documenting that it is not defined
> what the behaviour is, so we rememeber to list this as a known issue
> in 1.2.

OK.


>
>
> > ---
> >  content.tex | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/content.tex b/content.tex
> > index c6f116c..45751f4 100644
> > --- a/content.tex
> > +++ b/content.tex
> > @@ -4337,6 +4337,10 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi
> >  \field{virtqueue_pairs} once it has placed the
> >  VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET command in a used buffer.
> >
> > +If the destination receive queue is in reset state(See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}),
>
> Should this be "a reset state"? Also, I do not see any definition of "reset state" in
> the linked chapter. That chapter should really be cleaned up btw.

Oh, I will try to clean that.

>
> > +the device SHOULD re-select a different random queue.
>
> different from what?
>
> I suspect we want to move this:
>
> When multiqueue is enabled by VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET command, the device MUST use automatic receive steering
> based on packet flow. Programming of the receive steering
> classificator is implicit. After the driver transmitted a packet of a
> flow on transmitqX, the device SHOULD cause incoming packets for that flow to
> be steered to receiveqX. For uni-directional protocols, or where
> no packets have been transmitted yet, the device MAY steer a packet
> to a random queue out of the specified receiveq1\ldots receiveqn.
>
>
>
> to a conformance chapter, and be replaced with a general description
> avoiding conformance keyworkds like MUST and SHOULD.
>
>
> Generally, whenever we have conformance keywords out of conformance
> clauses it's a bug and source of confusion at some point.

Agreed, can we do some cleanup for these cases before 1.3.

Thanks.


>
>
> > If all receive queues are
> > +in reset state, the device MUST drop the packet.
> > +
> >  \subparagraph{Legacy Interface: Automatic receive steering in multiqueue mode}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Automatic receive steering in multiqueue mode / Legacy Interface: Automatic receive steering in multiqueue mode}
> >  When using the legacy interface, transitional devices and drivers
> >  MUST format \field{virtqueue_pairs}
> > @@ -4425,6 +4429,7 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi
> >  \item Calculate the hash of the packet as defined in \ref{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets}.
> >  \item If the device did not calculate the hash for the specific packet, the device directs the packet to the receiveq specified by \field{unclassified_queue} of virtio_net_rss_config structure (value of 0 corresponds to receiveq1).
> >  \item Apply \field{indirection_table_mask} to the calculated hash and use the result as the index in the indirection table to get 0-based number of destination receiveq (value of 0 corresponds to receiveq1).
> > +\item If the destination receive queue is in reset state(See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}), the device MUST drop the packet.
> >  \end{itemize}
> >
> >  \paragraph{Offloads State Configuration}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Offloads State Configuration}
> > --
> > 2.31.0
>

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