[virtio-comment] [PATCH] virtio-net: introduce admin control virtqueue

[virtio-comment] [PATCH] virtio-net: introduce admin control virtqueue

[Jason Wang]

When implementing multiple (sub)functions virtio device like SRIOV or
sub-function. We're suffering from several issues:

- There's no management interface for management function (PF) to
  configure features, attributes for a (sub)function
- Per (sub)function control virtqueue could be too expensive as the
  number of (sub)functions could be very large
- Virtualize per (sub)function control virtqueue could be very
  challenge as we need the support of DMA isolation at queue level

So this patch introduces the feature of VIRTIO_NET_CTRL_ADMIN_VQ. This
allows the device to implement a single admin control virtqueue to
manage per (sub)function features and attributes.

The idea is simple, a new function id is introduced on top of the
exist virtio_net_ctrl structure. This id is transport or device
specific to uniquely identify a (sub)function.

With this, we get a way of using management function (PF) to configure
per (sub)function features and attributes. And since the admin control
virtqueue belongs to management function (PF), the DMA is naturally
isolated at (sub)function level instead of the queue level for per
(sub)function control vq.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 content.tex | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/content.tex b/content.tex
index 620c0e2..98592a4 100644
--- a/content.tex
+++ b/content.tex
@@ -2940,6 +2940,9 @@ \subsection{Feature bits}\label{sec:Device Types / Network Device / Feature bits
 \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
     channel.
 
+\item[VIRTIO_NET_F_ADMIN_CTRL_VQ(56)] Admin control channel is
+    available.
+
 \item[VIRTIO_NET_F_HASH_REPORT(57)] Device can report per-packet hash
     value and a type of calculated hash.
 
@@ -3864,6 +3867,26 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi
 do except issue a diagnostic if \field{ack} is not
 VIRTIO_NET_OK.
 
+\subsubsection{Admin Control Virtqueue}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue}
+
+When VIRTIO_NET_F_ADMIN_CTRL_VQ is negotiated, the driver can use the
+control virtqueue to manipulate features of individual function where
+the control virtqueues is not easily implemented in each function.
+
+All commands are of the following form:
+
+\begin{lstlisting}
+struct virtio_net_admin_ctrl {
+        u32 function_id;
+        struct virtio_net_ctrl ctrl;
+};
+
+\end{lstlisting}
+
+The \field{function_id} is an unique transport or device specific
+identifier for a function. E.g for the case of PCI SRIOV, it's the id
+of PCI function.
+
 \paragraph{Packet Receive Filtering}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Packet Receive Filtering}
 \label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Setting Promiscuous Mode}%old label for latexdiff
 
-- 
2.25.1


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[virtio-comment] Re: [PATCH] virtio-net: introduce admin control virtqueue

[Michael S. Tsirkin]

On Fri, Jan 22, 2021 at 04:23:25PM +0800, Jason Wang wrote:
> When implementing multiple (sub)functions virtio device like SRIOV or
> sub-function. We're suffering from several issues:
> 
> - There's no management interface for management function (PF) to
>   configure features, attributes for a (sub)function
> - Per (sub)function control virtqueue could be too expensive as the
>   number of (sub)functions could be very large
> - Virtualize per (sub)function control virtqueue could be very
>   challenge as we need the support of DMA isolation at queue level
> 
> So this patch introduces the feature of VIRTIO_NET_CTRL_ADMIN_VQ. This
> allows the device to implement a single admin control virtqueue to
> manage per (sub)function features and attributes.
> 
> The idea is simple, a new function id is introduced on top of the
> exist virtio_net_ctrl structure. This id is transport or device
> specific to uniquely identify a (sub)function.
> 
> With this, we get a way of using management function (PF) to configure
> per (sub)function features and attributes. And since the admin control
> virtqueue belongs to management function (PF), the DMA is naturally
> isolated at (sub)function level instead of the queue level for per
> (sub)function control vq.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>

Let's specify how this works at least for PCI? What about sub-functions
under VF level? How are these specified?

> ---
>  content.tex | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
> 
> diff --git a/content.tex b/content.tex
> index 620c0e2..98592a4 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -2940,6 +2940,9 @@ \subsection{Feature bits}\label{sec:Device Types / Network Device / Feature bits
>  \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
>      channel.
>  
> +\item[VIRTIO_NET_F_ADMIN_CTRL_VQ(56)] Admin control channel is
> +    available.
> +
>  \item[VIRTIO_NET_F_HASH_REPORT(57)] Device can report per-packet hash
>      value and a type of calculated hash.
>  
> @@ -3864,6 +3867,26 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi
>  do except issue a diagnostic if \field{ack} is not
>  VIRTIO_NET_OK.
>  
> +\subsubsection{Admin Control Virtqueue}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue}
> +
> +When VIRTIO_NET_F_ADMIN_CTRL_VQ is negotiated, the driver can use the
> +control virtqueue to manipulate features of individual function where

manipulate features? You don't mean feature bits, do you?

> +the control virtqueues is not easily implemented in each function.
> +
> +All commands are of the following form:
> +
> +\begin{lstlisting}
> +struct virtio_net_admin_ctrl {
> +        u32 function_id;
> +        struct virtio_net_ctrl ctrl;
> +};
> +
> +\end{lstlisting}
> +
> +The \field{function_id} is an unique transport or device specific
> +identifier for a function. E.g for the case of PCI SRIOV, it's the id
> +of PCI function.
> +
>  \paragraph{Packet Receive Filtering}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Packet Receive Filtering}
>  \label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Setting Promiscuous Mode}%old label for latexdiff
>  
> -- 
> 2.25.1


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Re: [virtio-comment] Re: [PATCH] virtio-net: introduce admin control virtqueue

[Jason Wang]

----- Original Message -----
> On Fri, Jan 22, 2021 at 04:23:25PM +0800, Jason Wang wrote:
> > When implementing multiple (sub)functions virtio device like SRIOV or
> > sub-function. We're suffering from several issues:
> > 
> > - There's no management interface for management function (PF) to
> >   configure features, attributes for a (sub)function
> > - Per (sub)function control virtqueue could be too expensive as the
> >   number of (sub)functions could be very large
> > - Virtualize per (sub)function control virtqueue could be very
> >   challenge as we need the support of DMA isolation at queue level
> > 
> > So this patch introduces the feature of VIRTIO_NET_CTRL_ADMIN_VQ. This
> > allows the device to implement a single admin control virtqueue to
> > manage per (sub)function features and attributes.
> > 
> > The idea is simple, a new function id is introduced on top of the
> > exist virtio_net_ctrl structure. This id is transport or device
> > specific to uniquely identify a (sub)function.
> > 
> > With this, we get a way of using management function (PF) to configure
> > per (sub)function features and attributes. And since the admin control
> > virtqueue belongs to management function (PF), the DMA is naturally
> > isolated at (sub)function level instead of the queue level for per
> > (sub)function control vq.
> > 
> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> 
> Let's specify how this works at least for PCI? What about sub-functions
> under VF level? How are these specified?

Ok, will do.

> 
> > ---
> >  content.tex | 23 +++++++++++++++++++++++
> >  1 file changed, 23 insertions(+)
> > 
> > diff --git a/content.tex b/content.tex
> > index 620c0e2..98592a4 100644
> > --- a/content.tex
> > +++ b/content.tex
> > @@ -2940,6 +2940,9 @@ \subsection{Feature bits}\label{sec:Device Types /
> > Network Device / Feature bits
> >  \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
> >      channel.
> >  
> > +\item[VIRTIO_NET_F_ADMIN_CTRL_VQ(56)] Admin control channel is
> > +    available.
> > +
> >  \item[VIRTIO_NET_F_HASH_REPORT(57)] Device can report per-packet hash
> >      value and a type of calculated hash.
> >  
> > @@ -3864,6 +3867,26 @@ \subsubsection{Control Virtqueue}\label{sec:Device
> > Types / Network Device / Devi
> >  do except issue a diagnostic if \field{ack} is not
> >  VIRTIO_NET_OK.
> >  
> > +\subsubsection{Admin Control Virtqueue}\label{sec:Device Types / Network
> > Device / Device Operation / Control Virtqueue}
> > +
> > +When VIRTIO_NET_F_ADMIN_CTRL_VQ is negotiated, the driver can use the
> > +control virtqueue to manipulate features of individual function where
> 
> manipulate features? You don't mean feature bits, do you?

I copy from the control virtqueue paragraph above:

"""
The driver uses the control virtqueue (if VIRTIO_NET_F_CTRL_VQ is
negotiated) to send commands to manipulate various features of
the device which would not easily map into the configuration
space.
"""

Do we need to tweak that part as well?

Thanks

> 
> > +the control virtqueues is not easily implemented in each function.
> > +
> > +All commands are of the following form:
> > +
> > +\begin{lstlisting}
> > +struct virtio_net_admin_ctrl {
> > +        u32 function_id;
> > +        struct virtio_net_ctrl ctrl;
> > +};
> > +
> > +\end{lstlisting}
> > +
> > +The \field{function_id} is an unique transport or device specific
> > +identifier for a function. E.g for the case of PCI SRIOV, it's the id
> > +of PCI function.
> > +
> >  \paragraph{Packet Receive Filtering}\label{sec:Device Types / Network
> >  Device / Device Operation / Control Virtqueue / Packet Receive Filtering}
> >  \label{sec:Device Types / Network Device / Device Operation / Control
> >  Virtqueue / Setting Promiscuous Mode}%old label for latexdiff
> >  
> > --
> > 2.25.1
> 
> 
> This publicly archived list offers a means to provide input to the
> OASIS Virtual I/O Device (VIRTIO) TC.
> 
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> to minimize spam in the list archive, subscription is required
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> 


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Re: [virtio-comment] Re: [PATCH] virtio-net: introduce admin control virtqueue

[Michael S. Tsirkin]

On Fri, Jan 22, 2021 at 03:41:23AM -0500, Jason Wang wrote:
> 
> 
> ----- Original Message -----
> > On Fri, Jan 22, 2021 at 04:23:25PM +0800, Jason Wang wrote:
> > > When implementing multiple (sub)functions virtio device like SRIOV or
> > > sub-function. We're suffering from several issues:
> > > 
> > > - There's no management interface for management function (PF) to
> > >   configure features, attributes for a (sub)function
> > > - Per (sub)function control virtqueue could be too expensive as the
> > >   number of (sub)functions could be very large
> > > - Virtualize per (sub)function control virtqueue could be very
> > >   challenge as we need the support of DMA isolation at queue level
> > > 
> > > So this patch introduces the feature of VIRTIO_NET_CTRL_ADMIN_VQ. This
> > > allows the device to implement a single admin control virtqueue to
> > > manage per (sub)function features and attributes.
> > > 
> > > The idea is simple, a new function id is introduced on top of the
> > > exist virtio_net_ctrl structure. This id is transport or device
> > > specific to uniquely identify a (sub)function.
> > > 
> > > With this, we get a way of using management function (PF) to configure
> > > per (sub)function features and attributes. And since the admin control
> > > virtqueue belongs to management function (PF), the DMA is naturally
> > > isolated at (sub)function level instead of the queue level for per
> > > (sub)function control vq.
> > > 
> > > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > 
> > Let's specify how this works at least for PCI? What about sub-functions
> > under VF level? How are these specified?
> 
> Ok, will do.
> 
> > 
> > > ---
> > >  content.tex | 23 +++++++++++++++++++++++
> > >  1 file changed, 23 insertions(+)
> > > 
> > > diff --git a/content.tex b/content.tex
> > > index 620c0e2..98592a4 100644
> > > --- a/content.tex
> > > +++ b/content.tex
> > > @@ -2940,6 +2940,9 @@ \subsection{Feature bits}\label{sec:Device Types /
> > > Network Device / Feature bits
> > >  \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
> > >      channel.
> > >  
> > > +\item[VIRTIO_NET_F_ADMIN_CTRL_VQ(56)] Admin control channel is
> > > +    available.
> > > +
> > >  \item[VIRTIO_NET_F_HASH_REPORT(57)] Device can report per-packet hash
> > >      value and a type of calculated hash.
> > >  
> > > @@ -3864,6 +3867,26 @@ \subsubsection{Control Virtqueue}\label{sec:Device
> > > Types / Network Device / Devi
> > >  do except issue a diagnostic if \field{ack} is not
> > >  VIRTIO_NET_OK.
> > >  
> > > +\subsubsection{Admin Control Virtqueue}\label{sec:Device Types / Network
> > > Device / Device Operation / Control Virtqueue}
> > > +
> > > +When VIRTIO_NET_F_ADMIN_CTRL_VQ is negotiated, the driver can use the
> > > +control virtqueue to manipulate features of individual function where
> > 
> > manipulate features? You don't mean feature bits, do you?
> 
> I copy from the control virtqueue paragraph above:
> 
> """
> The driver uses the control virtqueue (if VIRTIO_NET_F_CTRL_VQ is
> negotiated) to send commands to manipulate various features of
> the device which would not easily map into the configuration
> space.
> """
> 
> Do we need to tweak that part as well?
> 
> Thanks

Maybe, but let's be a bit more specific. For example,
is it legal to manipulate the MAC of a VF?
When is it legal?


> > 
> > > +the control virtqueues is not easily implemented in each function.
> > > +
> > > +All commands are of the following form:
> > > +
> > > +\begin{lstlisting}
> > > +struct virtio_net_admin_ctrl {
> > > +        u32 function_id;
> > > +        struct virtio_net_ctrl ctrl;
> > > +};
> > > +
> > > +\end{lstlisting}
> > > +
> > > +The \field{function_id} is an unique transport or device specific
> > > +identifier for a function. E.g for the case of PCI SRIOV, it's the id
> > > +of PCI function.
> > > +
> > >  \paragraph{Packet Receive Filtering}\label{sec:Device Types / Network
> > >  Device / Device Operation / Control Virtqueue / Packet Receive Filtering}
> > >  \label{sec:Device Types / Network Device / Device Operation / Control
> > >  Virtqueue / Setting Promiscuous Mode}%old label for latexdiff
> > >  
> > > --
> > > 2.25.1
> > 
> > 
> > This publicly archived list offers a means to provide input to the
> > OASIS Virtual I/O Device (VIRTIO) TC.
> > 
> > In order to verify user consent to the Feedback License terms and
> > to minimize spam in the list archive, subscription is required
> > before posting.
> > 
> > Subscribe: virtio-comment-subscribe@lists.oasis-open.org
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> > Join OASIS: https://www.oasis-open.org/join/
> > 
> > 


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Re: [virtio-comment] Re: [PATCH] virtio-net: introduce admin control virtqueue

[Jason Wang]

----- Original Message -----
> On Fri, Jan 22, 2021 at 03:41:23AM -0500, Jason Wang wrote:
> > 
> > 
> > ----- Original Message -----
> > > On Fri, Jan 22, 2021 at 04:23:25PM +0800, Jason Wang wrote:
> > > > When implementing multiple (sub)functions virtio device like SRIOV or
> > > > sub-function. We're suffering from several issues:
> > > > 
> > > > - There's no management interface for management function (PF) to
> > > >   configure features, attributes for a (sub)function
> > > > - Per (sub)function control virtqueue could be too expensive as the
> > > >   number of (sub)functions could be very large
> > > > - Virtualize per (sub)function control virtqueue could be very
> > > >   challenge as we need the support of DMA isolation at queue level
> > > > 
> > > > So this patch introduces the feature of VIRTIO_NET_CTRL_ADMIN_VQ. This
> > > > allows the device to implement a single admin control virtqueue to
> > > > manage per (sub)function features and attributes.
> > > > 
> > > > The idea is simple, a new function id is introduced on top of the
> > > > exist virtio_net_ctrl structure. This id is transport or device
> > > > specific to uniquely identify a (sub)function.
> > > > 
> > > > With this, we get a way of using management function (PF) to configure
> > > > per (sub)function features and attributes. And since the admin control
> > > > virtqueue belongs to management function (PF), the DMA is naturally
> > > > isolated at (sub)function level instead of the queue level for per
> > > > (sub)function control vq.
> > > > 
> > > > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > > 
> > > Let's specify how this works at least for PCI? What about sub-functions
> > > under VF level? How are these specified?
> > 
> > Ok, will do.
> > 
> > > 
> > > > ---
> > > >  content.tex | 23 +++++++++++++++++++++++
> > > >  1 file changed, 23 insertions(+)
> > > > 
> > > > diff --git a/content.tex b/content.tex
> > > > index 620c0e2..98592a4 100644
> > > > --- a/content.tex
> > > > +++ b/content.tex
> > > > @@ -2940,6 +2940,9 @@ \subsection{Feature bits}\label{sec:Device Types
> > > > /
> > > > Network Device / Feature bits
> > > >  \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
> > > >      channel.
> > > >  
> > > > +\item[VIRTIO_NET_F_ADMIN_CTRL_VQ(56)] Admin control channel is
> > > > +    available.
> > > > +
> > > >  \item[VIRTIO_NET_F_HASH_REPORT(57)] Device can report per-packet hash
> > > >      value and a type of calculated hash.
> > > >  
> > > > @@ -3864,6 +3867,26 @@ \subsubsection{Control
> > > > Virtqueue}\label{sec:Device
> > > > Types / Network Device / Devi
> > > >  do except issue a diagnostic if \field{ack} is not
> > > >  VIRTIO_NET_OK.
> > > >  
> > > > +\subsubsection{Admin Control Virtqueue}\label{sec:Device Types /
> > > > Network
> > > > Device / Device Operation / Control Virtqueue}
> > > > +
> > > > +When VIRTIO_NET_F_ADMIN_CTRL_VQ is negotiated, the driver can use the
> > > > +control virtqueue to manipulate features of individual function where
> > > 
> > > manipulate features? You don't mean feature bits, do you?
> > 
> > I copy from the control virtqueue paragraph above:
> > 
> > """
> > The driver uses the control virtqueue (if VIRTIO_NET_F_CTRL_VQ is
> > negotiated) to send commands to manipulate various features of
> > the device which would not easily map into the configuration
> > space.
> > """
> > 
> > Do we need to tweak that part as well?
> > 
> > Thanks
> 
> Maybe, but let's be a bit more specific. For example,
> is it legal to manipulate the MAC of a VF?

Right, so we can clarify that the admin control virtqueue should be
only used/advertised for the management function like PF. When
neogiated, it's always legal to manipulte the MAC of VF through it.

> When is it legal?

Or do you mean some like "trust" command for iproute2 that allows VF
to change its own mac?

When PF has admin cvq and VF has normal cvq, management software needs
to synrhonize the setting of mac address. E.g management won't set mac
address after VM is launched.

Thanks

> 
> 
> > > 
> > > > +the control virtqueues is not easily implemented in each function.
> > > > +
> > > > +All commands are of the following form:
> > > > +
> > > > +\begin{lstlisting}
> > > > +struct virtio_net_admin_ctrl {
> > > > +        u32 function_id;
> > > > +        struct virtio_net_ctrl ctrl;
> > > > +};
> > > > +
> > > > +\end{lstlisting}
> > > > +
> > > > +The \field{function_id} is an unique transport or device specific
> > > > +identifier for a function. E.g for the case of PCI SRIOV, it's the id
> > > > +of PCI function.
> > > > +
> > > >  \paragraph{Packet Receive Filtering}\label{sec:Device Types / Network
> > > >  Device / Device Operation / Control Virtqueue / Packet Receive
> > > >  Filtering}
> > > >  \label{sec:Device Types / Network Device / Device Operation / Control
> > > >  Virtqueue / Setting Promiscuous Mode}%old label for latexdiff
> > > >  
> > > > --
> > > > 2.25.1
> > > 
> > > 
> > > This publicly archived list offers a means to provide input to the
> > > OASIS Virtual I/O Device (VIRTIO) TC.
> > > 
> > > In order to verify user consent to the Feedback License terms and
> > > to minimize spam in the list archive, subscription is required
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Re: [virtio-comment] Re: [PATCH] virtio-net: introduce admin control virtqueue

[Michael S. Tsirkin]

On Fri, Jan 22, 2021 at 04:14:19AM -0500, Jason Wang wrote:
> ----- Original Message -----
> > On Fri, Jan 22, 2021 at 03:41:23AM -0500, Jason Wang wrote:
> > > 
> > > 
> > > ----- Original Message -----
> > > > On Fri, Jan 22, 2021 at 04:23:25PM +0800, Jason Wang wrote:
> > > > > When implementing multiple (sub)functions virtio device like SRIOV or
> > > > > sub-function. We're suffering from several issues:
> > > > > 
> > > > > - There's no management interface for management function (PF) to
> > > > >   configure features, attributes for a (sub)function
> > > > > - Per (sub)function control virtqueue could be too expensive as the
> > > > >   number of (sub)functions could be very large
> > > > > - Virtualize per (sub)function control virtqueue could be very
> > > > >   challenge as we need the support of DMA isolation at queue level
> > > > > 
> > > > > So this patch introduces the feature of VIRTIO_NET_CTRL_ADMIN_VQ. This
> > > > > allows the device to implement a single admin control virtqueue to
> > > > > manage per (sub)function features and attributes.
> > > > > 
> > > > > The idea is simple, a new function id is introduced on top of the
> > > > > exist virtio_net_ctrl structure. This id is transport or device
> > > > > specific to uniquely identify a (sub)function.
> > > > > 
> > > > > With this, we get a way of using management function (PF) to configure
> > > > > per (sub)function features and attributes. And since the admin control
> > > > > virtqueue belongs to management function (PF), the DMA is naturally
> > > > > isolated at (sub)function level instead of the queue level for per
> > > > > (sub)function control vq.
> > > > > 
> > > > > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > > > 
> > > > Let's specify how this works at least for PCI? What about sub-functions
> > > > under VF level? How are these specified?
> > > 
> > > Ok, will do.
> > > 
> > > > 
> > > > > ---
> > > > >  content.tex | 23 +++++++++++++++++++++++
> > > > >  1 file changed, 23 insertions(+)
> > > > > 
> > > > > diff --git a/content.tex b/content.tex
> > > > > index 620c0e2..98592a4 100644
> > > > > --- a/content.tex
> > > > > +++ b/content.tex
> > > > > @@ -2940,6 +2940,9 @@ \subsection{Feature bits}\label{sec:Device Types
> > > > > /
> > > > > Network Device / Feature bits
> > > > >  \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
> > > > >      channel.
> > > > >  
> > > > > +\item[VIRTIO_NET_F_ADMIN_CTRL_VQ(56)] Admin control channel is
> > > > > +    available.
> > > > > +
> > > > >  \item[VIRTIO_NET_F_HASH_REPORT(57)] Device can report per-packet hash
> > > > >      value and a type of calculated hash.
> > > > >  
> > > > > @@ -3864,6 +3867,26 @@ \subsubsection{Control
> > > > > Virtqueue}\label{sec:Device
> > > > > Types / Network Device / Devi
> > > > >  do except issue a diagnostic if \field{ack} is not
> > > > >  VIRTIO_NET_OK.
> > > > >  
> > > > > +\subsubsection{Admin Control Virtqueue}\label{sec:Device Types /
> > > > > Network
> > > > > Device / Device Operation / Control Virtqueue}
> > > > > +
> > > > > +When VIRTIO_NET_F_ADMIN_CTRL_VQ is negotiated, the driver can use the
> > > > > +control virtqueue to manipulate features of individual function where
> > > > 
> > > > manipulate features? You don't mean feature bits, do you?
> > > 
> > > I copy from the control virtqueue paragraph above:
> > > 
> > > """
> > > The driver uses the control virtqueue (if VIRTIO_NET_F_CTRL_VQ is
> > > negotiated) to send commands to manipulate various features of
> > > the device which would not easily map into the configuration
> > > space.
> > > """
> > > 
> > > Do we need to tweak that part as well?
> > > 
> > > Thanks
> > 
> > Maybe, but let's be a bit more specific. For example,
> > is it legal to manipulate the MAC of a VF?
> 
> Right, so we can clarify that the admin control virtqueue should be
> only used/advertised for the management function like PF. When
> neogiated, it's always legal to manipulte the MAC of VF through it.
> 
> > When is it legal?
> 
> Or do you mean some like "trust" command for iproute2 that allows VF
> to change its own mac?
> 
> When PF has admin cvq and VF has normal cvq, management software needs
> to synrhonize the setting of mac address. E.g management won't set mac
> address after VM is launched.
> 
> Thanks

Consider.
VF has VIRTIO_NET_F_CTRL_MAC_ADDR. This means guest can set mac address.
This is something PF needs ability to control. How is this done?

Also, does PF allow setting guest MAC? when? when PF has
VIRTIO_NET_F_CTRL_MAC_ADDR? Do we differentiate between
that and ability to set MAC for pf?




> > 
> > 
> > > > 
> > > > > +the control virtqueues is not easily implemented in each function.
> > > > > +
> > > > > +All commands are of the following form:
> > > > > +
> > > > > +\begin{lstlisting}
> > > > > +struct virtio_net_admin_ctrl {
> > > > > +        u32 function_id;
> > > > > +        struct virtio_net_ctrl ctrl;
> > > > > +};
> > > > > +
> > > > > +\end{lstlisting}
> > > > > +
> > > > > +The \field{function_id} is an unique transport or device specific
> > > > > +identifier for a function. E.g for the case of PCI SRIOV, it's the id
> > > > > +of PCI function.
> > > > > +
> > > > >  \paragraph{Packet Receive Filtering}\label{sec:Device Types / Network
> > > > >  Device / Device Operation / Control Virtqueue / Packet Receive
> > > > >  Filtering}
> > > > >  \label{sec:Device Types / Network Device / Device Operation / Control
> > > > >  Virtqueue / Setting Promiscuous Mode}%old label for latexdiff
> > > > >  
> > > > > --
> > > > > 2.25.1
> > > > 
> > > > 
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Re: [virtio-comment] Re: [PATCH] virtio-net: introduce admin control virtqueue

[Jason Wang]

On 2021/1/22 下午8:14, Michael S. Tsirkin wrote:
> On Fri, Jan 22, 2021 at 04:14:19AM -0500, Jason Wang wrote:
>> ----- Original Message -----
>>> On Fri, Jan 22, 2021 at 03:41:23AM -0500, Jason Wang wrote:
>>>> ----- Original Message -----
>>>>> On Fri, Jan 22, 2021 at 04:23:25PM +0800, Jason Wang wrote:
>>>>>> When implementing multiple (sub)functions virtio device like SRIOV or
>>>>>> sub-function. We're suffering from several issues:
>>>>>>
>>>>>> - There's no management interface for management function (PF) to
>>>>>>    configure features, attributes for a (sub)function
>>>>>> - Per (sub)function control virtqueue could be too expensive as the
>>>>>>    number of (sub)functions could be very large
>>>>>> - Virtualize per (sub)function control virtqueue could be very
>>>>>>    challenge as we need the support of DMA isolation at queue level
>>>>>>
>>>>>> So this patch introduces the feature of VIRTIO_NET_CTRL_ADMIN_VQ. This
>>>>>> allows the device to implement a single admin control virtqueue to
>>>>>> manage per (sub)function features and attributes.
>>>>>>
>>>>>> The idea is simple, a new function id is introduced on top of the
>>>>>> exist virtio_net_ctrl structure. This id is transport or device
>>>>>> specific to uniquely identify a (sub)function.
>>>>>>
>>>>>> With this, we get a way of using management function (PF) to configure
>>>>>> per (sub)function features and attributes. And since the admin control
>>>>>> virtqueue belongs to management function (PF), the DMA is naturally
>>>>>> isolated at (sub)function level instead of the queue level for per
>>>>>> (sub)function control vq.
>>>>>>
>>>>>> Signed-off-by: Jason Wang<jasowang@redhat.com>
>>>>> Let's specify how this works at least for PCI? What about sub-functions
>>>>> under VF level? How are these specified?
>>>> Ok, will do.
>>>>
>>>>>> ---
>>>>>>   content.tex | 23 +++++++++++++++++++++++
>>>>>>   1 file changed, 23 insertions(+)
>>>>>>
>>>>>> diff --git a/content.tex b/content.tex
>>>>>> index 620c0e2..98592a4 100644
>>>>>> --- a/content.tex
>>>>>> +++ b/content.tex
>>>>>> @@ -2940,6 +2940,9 @@ \subsection{Feature bits}\label{sec:Device Types
>>>>>> /
>>>>>> Network Device / Feature bits
>>>>>>   \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
>>>>>>       channel.
>>>>>>   
>>>>>> +\item[VIRTIO_NET_F_ADMIN_CTRL_VQ(56)] Admin control channel is
>>>>>> +    available.
>>>>>> +
>>>>>>   \item[VIRTIO_NET_F_HASH_REPORT(57)] Device can report per-packet hash
>>>>>>       value and a type of calculated hash.
>>>>>>   
>>>>>> @@ -3864,6 +3867,26 @@ \subsubsection{Control
>>>>>> Virtqueue}\label{sec:Device
>>>>>> Types / Network Device / Devi
>>>>>>   do except issue a diagnostic if \field{ack} is not
>>>>>>   VIRTIO_NET_OK.
>>>>>>   
>>>>>> +\subsubsection{Admin Control Virtqueue}\label{sec:Device Types /
>>>>>> Network
>>>>>> Device / Device Operation / Control Virtqueue}
>>>>>> +
>>>>>> +When VIRTIO_NET_F_ADMIN_CTRL_VQ is negotiated, the driver can use the
>>>>>> +control virtqueue to manipulate features of individual function where
>>>>> manipulate features? You don't mean feature bits, do you?
>>>> I copy from the control virtqueue paragraph above:
>>>>
>>>> """
>>>> The driver uses the control virtqueue (if VIRTIO_NET_F_CTRL_VQ is
>>>> negotiated) to send commands to manipulate various features of
>>>> the device which would not easily map into the configuration
>>>> space.
>>>> """
>>>>
>>>> Do we need to tweak that part as well?
>>>>
>>>> Thanks
>>> Maybe, but let's be a bit more specific. For example,
>>> is it legal to manipulate the MAC of a VF?
>> Right, so we can clarify that the admin control virtqueue should be
>> only used/advertised for the management function like PF. When
>> neogiated, it's always legal to manipulte the MAC of VF through it.
>>
>>> When is it legal?
>> Or do you mean some like "trust" command for iproute2 that allows VF
>> to change its own mac?
>>
>> When PF has admin cvq and VF has normal cvq, management software needs
>> to synrhonize the setting of mac address. E.g management won't set mac
>> address after VM is launched.
>>
>> Thanks
> Consider.
> VF has VIRTIO_NET_F_CTRL_MAC_ADDR. This means guest can set mac address.
> This is something PF needs ability to control. How is this done?


This requires a new command to allow/deny the mac address setting from 
the VF.


>
> Also, does PF allow setting guest MAC?


I think the answer is yes.


> when?


It will work as how ip set vf mac work. Usually, it should be done 
before launching the guest. Management should make sure there's no 
conflict in mac address updating.


>   when PF has
> VIRTIO_NET_F_CTRL_MAC_ADDR?


Yes, without this feature. We can't set mac address through admin 
control virtqueue.


> Do we differentiate between
> that and ability to set MAC for pf?


I think not. E.g PF should have a dedicated function_id (or virtual 
device id) like 0. Then we can set mac address of PF through admin cvq.

Thanks

>
>
>
>


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Re: [virtio-comment] [PATCH] virtio-net: introduce admin control virtqueue

[Cornelia Huck]

On Fri, 22 Jan 2021 16:23:25 +0800
Jason Wang <jasowang@redhat.com> wrote:

> When implementing multiple (sub)functions virtio device like SRIOV or
> sub-function. We're suffering from several issues:
> 
> - There's no management interface for management function (PF) to
>   configure features, attributes for a (sub)function
> - Per (sub)function control virtqueue could be too expensive as the
>   number of (sub)functions could be very large
> - Virtualize per (sub)function control virtqueue could be very
>   challenge as we need the support of DMA isolation at queue level
> 
> So this patch introduces the feature of VIRTIO_NET_CTRL_ADMIN_VQ. This
> allows the device to implement a single admin control virtqueue to
> manage per (sub)function features and attributes.
> 
> The idea is simple, a new function id is introduced on top of the
> exist virtio_net_ctrl structure. This id is transport or device
> specific to uniquely identify a (sub)function.
> 
> With this, we get a way of using management function (PF) to configure
> per (sub)function features and attributes. And since the admin control
> virtqueue belongs to management function (PF), the DMA is naturally
> isolated at (sub)function level instead of the queue level for per
> (sub)function control vq.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  content.tex | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
> 
> diff --git a/content.tex b/content.tex
> index 620c0e2..98592a4 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -2940,6 +2940,9 @@ \subsection{Feature bits}\label{sec:Device Types / Network Device / Feature bits
>  \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
>      channel.
>  
> +\item[VIRTIO_NET_F_ADMIN_CTRL_VQ(56)] Admin control channel is
> +    available.
> +
>  \item[VIRTIO_NET_F_HASH_REPORT(57)] Device can report per-packet hash
>      value and a type of calculated hash.
>  
> @@ -3864,6 +3867,26 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi
>  do except issue a diagnostic if \field{ack} is not
>  VIRTIO_NET_OK.
>  
> +\subsubsection{Admin Control Virtqueue}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue}
> +
> +When VIRTIO_NET_F_ADMIN_CTRL_VQ is negotiated, the driver can use the
> +control virtqueue to manipulate features of individual function where
> +the control virtqueues is not easily implemented in each function.

What is a 'function' in the context of the virtio-net device? I don't
think that this term is universal across transports.

> +
> +All commands are of the following form:
> +
> +\begin{lstlisting}
> +struct virtio_net_admin_ctrl {
> +        u32 function_id;
> +        struct virtio_net_ctrl ctrl;
> +};
> +
> +\end{lstlisting}
> +
> +The \field{function_id} is an unique transport or device specific
> +identifier for a function. E.g for the case of PCI SRIOV, it's the id
> +of PCI function.
> +
>  \paragraph{Packet Receive Filtering}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Packet Receive Filtering}
>  \label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Setting Promiscuous Mode}%old label for latexdiff
>  


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Re: [virtio-comment] [PATCH] virtio-net: introduce admin control virtqueue

[Jason Wang]

On 2021/1/22 下午6:11, Cornelia Huck wrote:
> On Fri, 22 Jan 2021 16:23:25 +0800
> Jason Wang<jasowang@redhat.com>  wrote:
>
>> When implementing multiple (sub)functions virtio device like SRIOV or
>> sub-function. We're suffering from several issues:
>>
>> - There's no management interface for management function (PF) to
>>    configure features, attributes for a (sub)function
>> - Per (sub)function control virtqueue could be too expensive as the
>>    number of (sub)functions could be very large
>> - Virtualize per (sub)function control virtqueue could be very
>>    challenge as we need the support of DMA isolation at queue level
>>
>> So this patch introduces the feature of VIRTIO_NET_CTRL_ADMIN_VQ. This
>> allows the device to implement a single admin control virtqueue to
>> manage per (sub)function features and attributes.
>>
>> The idea is simple, a new function id is introduced on top of the
>> exist virtio_net_ctrl structure. This id is transport or device
>> specific to uniquely identify a (sub)function.
>>
>> With this, we get a way of using management function (PF) to configure
>> per (sub)function features and attributes. And since the admin control
>> virtqueue belongs to management function (PF), the DMA is naturally
>> isolated at (sub)function level instead of the queue level for per
>> (sub)function control vq.
>>
>> Signed-off-by: Jason Wang<jasowang@redhat.com>
>> ---
>>   content.tex | 23 +++++++++++++++++++++++
>>   1 file changed, 23 insertions(+)
>>
>> diff --git a/content.tex b/content.tex
>> index 620c0e2..98592a4 100644
>> --- a/content.tex
>> +++ b/content.tex
>> @@ -2940,6 +2940,9 @@ \subsection{Feature bits}\label{sec:Device Types / Network Device / Feature bits
>>   \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
>>       channel.
>>   
>> +\item[VIRTIO_NET_F_ADMIN_CTRL_VQ(56)] Admin control channel is
>> +    available.
>> +
>>   \item[VIRTIO_NET_F_HASH_REPORT(57)] Device can report per-packet hash
>>       value and a type of calculated hash.
>>   
>> @@ -3864,6 +3867,26 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi
>>   do except issue a diagnostic if \field{ack} is not
>>   VIRTIO_NET_OK.
>>   
>> +\subsubsection{Admin Control Virtqueue}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue}
>> +
>> +When VIRTIO_NET_F_ADMIN_CTRL_VQ is negotiated, the driver can use the
>> +control virtqueue to manipulate features of individual function where
>> +the control virtqueues is not easily implemented in each function.
> What is a 'function' in the context of the virtio-net device? I don't
> think that this term is universal across transports.


Good point. It might have well definition only in PCI.

I wonder whether we can use "virtual device" here? It avoids transport 
specific terminology. And we can explain "virtual device" in one or two 
sentences here.

Thanks


>


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Re: [virtio-comment] [PATCH] virtio-net: introduce admin control virtqueue

[Jason Wang]

----- Original Message -----
> 
> On 2021/1/22 下午6:11, Cornelia Huck wrote:
> > On Fri, 22 Jan 2021 16:23:25 +0800
> > Jason Wang<jasowang@redhat.com>  wrote:
> >
> >> When implementing multiple (sub)functions virtio device like SRIOV or
> >> sub-function. We're suffering from several issues:
> >>
> >> - There's no management interface for management function (PF) to
> >>    configure features, attributes for a (sub)function
> >> - Per (sub)function control virtqueue could be too expensive as the
> >>    number of (sub)functions could be very large
> >> - Virtualize per (sub)function control virtqueue could be very
> >>    challenge as we need the support of DMA isolation at queue level
> >>
> >> So this patch introduces the feature of VIRTIO_NET_CTRL_ADMIN_VQ. This
> >> allows the device to implement a single admin control virtqueue to
> >> manage per (sub)function features and attributes.
> >>
> >> The idea is simple, a new function id is introduced on top of the
> >> exist virtio_net_ctrl structure. This id is transport or device
> >> specific to uniquely identify a (sub)function.
> >>
> >> With this, we get a way of using management function (PF) to configure
> >> per (sub)function features and attributes. And since the admin control
> >> virtqueue belongs to management function (PF), the DMA is naturally
> >> isolated at (sub)function level instead of the queue level for per
> >> (sub)function control vq.
> >>
> >> Signed-off-by: Jason Wang<jasowang@redhat.com>
> >> ---
> >>   content.tex | 23 +++++++++++++++++++++++
> >>   1 file changed, 23 insertions(+)
> >>
> >> diff --git a/content.tex b/content.tex
> >> index 620c0e2..98592a4 100644
> >> --- a/content.tex
> >> +++ b/content.tex
> >> @@ -2940,6 +2940,9 @@ \subsection{Feature bits}\label{sec:Device Types /
> >> Network Device / Feature bits
> >>   \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
> >>       channel.
> >>   
> >> +\item[VIRTIO_NET_F_ADMIN_CTRL_VQ(56)] Admin control channel is
> >> +    available.
> >> +
> >>   \item[VIRTIO_NET_F_HASH_REPORT(57)] Device can report per-packet hash
> >>       value and a type of calculated hash.
> >>   
> >> @@ -3864,6 +3867,26 @@ \subsubsection{Control Virtqueue}\label{sec:Device
> >> Types / Network Device / Devi
> >>   do except issue a diagnostic if \field{ack} is not
> >>   VIRTIO_NET_OK.
> >>   
> >> +\subsubsection{Admin Control Virtqueue}\label{sec:Device Types / Network
> >> Device / Device Operation / Control Virtqueue}
> >> +
> >> +When VIRTIO_NET_F_ADMIN_CTRL_VQ is negotiated, the driver can use the
> >> +control virtqueue to manipulate features of individual function where
> >> +the control virtqueues is not easily implemented in each function.
> > What is a 'function' in the context of the virtio-net device? I don't
> > think that this term is universal across transports.
> 
> 
> Good point. It might have well definition only in PCI.
> 
> I wonder whether we can use "virtual device" here? It avoids transport
> specific terminology. And we can explain "virtual device" in one or two
> sentences here.
> 
> Thanks


Something like:

When VIRTIO_NET_F_ADMIN_CTRL_VQ is negotiated, the driver can use the
admin control virtqueue of the management device to manipulate
features of individual virtual devices where the control virtqueue is
not easily implemented. The definition of management device and
virtual device is totally transport specific. E.g in the case of PCI
transport, the management device is usually the physical function (PF),
and the virtual device is the virtual function (VF).

Thanks

> 
> 
> >
> 
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