[virtio-comment] [PATCH v4] clarify device reset

[virtio-comment] [PATCH v4] clarify device reset

[Cornelia Huck]

Properly specify that the method for the driver to request a
device reset is transport specific, and some action the device
has to take.

Signed-off-by: Cornelia Huck <cohuck@redhat.com>
---

Stefan, Halil: I did not apply your R-b due to the amount of changes.

v3 -> v4:
  - moved device status 're-initialize to 0' clause that is now duplicated
    to an informal description
  - more clarifications on when reset may be used and device requirements
  - use \field{device status} consistently
RFC v2 -> v3:
  - re-worded the "must not send notifications" clause to avoid guessing
  - added a driver conformance clause on how a driver should find out
    when reset is complete
RFC -> RFC v2:
  - moved reset spec to basic facilities

---
 conformance.tex |  2 ++
 content.tex     | 24 +++++++++++++++++++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/conformance.tex b/conformance.tex
index e78adfdbd283..17c390d249db 100644
--- a/conformance.tex
+++ b/conformance.tex
@@ -64,6 +64,7 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets}
 \begin{itemize}
 \item \ref{drivernormative:Basic Facilities of a Virtio Device / Device Status Field}
 \item \ref{drivernormative:Basic Facilities of a Virtio Device / Feature Bits}
+\item \ref{drivernormative:Basic Facilities of a Virtio Device / Device Reset}
 \item \ref{drivernormative:Basic Facilities of a Virtio Device / Device Configuration Space}
 \item \ref{drivernormative:Basic Facilities of a Virtio Device / Virtqueues}
 \item \ref{drivernormative:Basic Facilities of a Virtio Device / Message Framing}
@@ -283,6 +284,7 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets}
 \begin{itemize}
 \item \ref{devicenormative:Basic Facilities of a Virtio Device / Device Status Field}
 \item \ref{devicenormative:Basic Facilities of a Virtio Device / Feature Bits}
+\item \ref{devicenormative:Basic Facilities of a Virtio Device / Device Reset}
 \item \ref{devicenormative:Basic Facilities of a Virtio Device / Device Configuration Space}
 \item \ref{devicenormative:Basic Facilities of a Virtio Device / Message Framing}
 \item \ref{devicenormative:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table}
diff --git a/content.tex b/content.tex
index 1ca24c13f2d0..47239b877c6c 100644
--- a/content.tex
+++ b/content.tex
@@ -51,6 +51,9 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev
   an error from which it can't recover.
 \end{description}
 
+The \field{device status} field starts out as 0, and is reinitialized to 0 by
+the device during reset.
+
 \drivernormative{\subsection}{Device Status Field}{Basic Facilities of a Virtio Device / Device Status Field}
 The driver MUST update \field{device status},
 setting bits to indicate the completed steps of the driver
@@ -71,7 +74,6 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev
 \end{note}
 
 \devicenormative{\subsection}{Device Status Field}{Basic Facilities of a Virtio Device / Device Status Field}
-The device MUST initialize \field{device status} to 0 upon reset.
 
 The device MUST NOT consume buffers or send any used buffer
 notifications to the driver before DRIVER_OK.
@@ -193,6 +195,26 @@ \section{Notifications}\label{sec:Basic Facilities of a Virtio Device
 terminology. Occasionally, the term event is used to refer to
 a notification or a receipt of a notification.
 
+\section{Device Reset}\label{sec:Basic Facilities of a Virtio Device / Device Reset}
+
+The driver may want to initiate a device reset at various times; notably,
+it is required to do so during device initialization and device cleanup.
+
+The mechanism used by the driver to initiate the reset is transport specific.
+
+\devicenormative{\subsection}{Device Reset}{Basic Facilities of a Virtio Device / Device Reset}
+
+A device MUST reinitialize \field{device status} to 0 after receiving a reset.
+
+A device MUST NOT send notifications or interact with the queues after
+indicating completion of the reset by reinitializing \field{device status}
+to 0, until the driver re-initializes the device.
+
+\drivernormative{\subsection}{Device Reset}{Basic Facilities of a Virtio Device / Device Reset}
+
+The driver SHOULD consider a driver-initiated reset complete when it
+reads \field{device status} as 0.
+
 \section{Device Configuration Space}\label{sec:Basic Facilities of a Virtio Device / Device Configuration Space}
 
 Device configuration space is generally used for rarely-changing or
-- 
2.26.2


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[virtio-comment] Re: [PATCH v4] clarify device reset

[Jason Wang]

On 2021/1/28 下午9:52, Cornelia Huck wrote:
> Properly specify that the method for the driver to request a
> device reset is transport specific, and some action the device
> has to take.
>
> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> ---
>
> Stefan, Halil: I did not apply your R-b due to the amount of changes.
>
> v3 -> v4:
>    - moved device status 're-initialize to 0' clause that is now duplicated
>      to an informal description
>    - more clarifications on when reset may be used and device requirements
>    - use \field{device status} consistently
> RFC v2 -> v3:
>    - re-worded the "must not send notifications" clause to avoid guessing
>    - added a driver conformance clause on how a driver should find out
>      when reset is complete
> RFC -> RFC v2:
>    - moved reset spec to basic facilities
>
> ---
>   conformance.tex |  2 ++
>   content.tex     | 24 +++++++++++++++++++++++-
>   2 files changed, 25 insertions(+), 1 deletion(-)


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


>
> diff --git a/conformance.tex b/conformance.tex
> index e78adfdbd283..17c390d249db 100644
> --- a/conformance.tex
> +++ b/conformance.tex
> @@ -64,6 +64,7 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets}
>   \begin{itemize}
>   \item \ref{drivernormative:Basic Facilities of a Virtio Device / Device Status Field}
>   \item \ref{drivernormative:Basic Facilities of a Virtio Device / Feature Bits}
> +\item \ref{drivernormative:Basic Facilities of a Virtio Device / Device Reset}
>   \item \ref{drivernormative:Basic Facilities of a Virtio Device / Device Configuration Space}
>   \item \ref{drivernormative:Basic Facilities of a Virtio Device / Virtqueues}
>   \item \ref{drivernormative:Basic Facilities of a Virtio Device / Message Framing}
> @@ -283,6 +284,7 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets}
>   \begin{itemize}
>   \item \ref{devicenormative:Basic Facilities of a Virtio Device / Device Status Field}
>   \item \ref{devicenormative:Basic Facilities of a Virtio Device / Feature Bits}
> +\item \ref{devicenormative:Basic Facilities of a Virtio Device / Device Reset}
>   \item \ref{devicenormative:Basic Facilities of a Virtio Device / Device Configuration Space}
>   \item \ref{devicenormative:Basic Facilities of a Virtio Device / Message Framing}
>   \item \ref{devicenormative:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table}
> diff --git a/content.tex b/content.tex
> index 1ca24c13f2d0..47239b877c6c 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -51,6 +51,9 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev
>     an error from which it can't recover.
>   \end{description}
>   
> +The \field{device status} field starts out as 0, and is reinitialized to 0 by
> +the device during reset.
> +
>   \drivernormative{\subsection}{Device Status Field}{Basic Facilities of a Virtio Device / Device Status Field}
>   The driver MUST update \field{device status},
>   setting bits to indicate the completed steps of the driver
> @@ -71,7 +74,6 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev
>   \end{note}
>   
>   \devicenormative{\subsection}{Device Status Field}{Basic Facilities of a Virtio Device / Device Status Field}
> -The device MUST initialize \field{device status} to 0 upon reset.
>   
>   The device MUST NOT consume buffers or send any used buffer
>   notifications to the driver before DRIVER_OK.
> @@ -193,6 +195,26 @@ \section{Notifications}\label{sec:Basic Facilities of a Virtio Device
>   terminology. Occasionally, the term event is used to refer to
>   a notification or a receipt of a notification.
>   
> +\section{Device Reset}\label{sec:Basic Facilities of a Virtio Device / Device Reset}
> +
> +The driver may want to initiate a device reset at various times; notably,
> +it is required to do so during device initialization and device cleanup.
> +
> +The mechanism used by the driver to initiate the reset is transport specific.
> +
> +\devicenormative{\subsection}{Device Reset}{Basic Facilities of a Virtio Device / Device Reset}
> +
> +A device MUST reinitialize \field{device status} to 0 after receiving a reset.
> +
> +A device MUST NOT send notifications or interact with the queues after
> +indicating completion of the reset by reinitializing \field{device status}
> +to 0, until the driver re-initializes the device.
> +
> +\drivernormative{\subsection}{Device Reset}{Basic Facilities of a Virtio Device / Device Reset}
> +
> +The driver SHOULD consider a driver-initiated reset complete when it
> +reads \field{device status} as 0.
> +
>   \section{Device Configuration Space}\label{sec:Basic Facilities of a Virtio Device / Device Configuration Space}
>   
>   Device configuration space is generally used for rarely-changing or


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[virtio-comment] Re: [PATCH v4] clarify device reset

[Cornelia Huck]

On Thu, 28 Jan 2021 14:52:35 +0100
Cornelia Huck <cohuck@redhat.com> wrote:

> Properly specify that the method for the driver to request a
> device reset is transport specific, and some action the device
> has to take.

Fixes: https://github.com/oasis-tcs/virtio-spec/issues/93

> 
> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> ---
> 
> Stefan, Halil: I did not apply your R-b due to the amount of changes.
> 
> v3 -> v4:
>   - moved device status 're-initialize to 0' clause that is now duplicated
>     to an informal description
>   - more clarifications on when reset may be used and device requirements
>   - use \field{device status} consistently
> RFC v2 -> v3:
>   - re-worded the "must not send notifications" clause to avoid guessing
>   - added a driver conformance clause on how a driver should find out
>     when reset is complete
> RFC -> RFC v2:
>   - moved reset spec to basic facilities
> 
> ---
>  conformance.tex |  2 ++
>  content.tex     | 24 +++++++++++++++++++++++-
>  2 files changed, 25 insertions(+), 1 deletion(-)
> 
> diff --git a/conformance.tex b/conformance.tex
> index e78adfdbd283..17c390d249db 100644
> --- a/conformance.tex
> +++ b/conformance.tex
> @@ -64,6 +64,7 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets}
>  \begin{itemize}
>  \item \ref{drivernormative:Basic Facilities of a Virtio Device / Device Status Field}
>  \item \ref{drivernormative:Basic Facilities of a Virtio Device / Feature Bits}
> +\item \ref{drivernormative:Basic Facilities of a Virtio Device / Device Reset}
>  \item \ref{drivernormative:Basic Facilities of a Virtio Device / Device Configuration Space}
>  \item \ref{drivernormative:Basic Facilities of a Virtio Device / Virtqueues}
>  \item \ref{drivernormative:Basic Facilities of a Virtio Device / Message Framing}
> @@ -283,6 +284,7 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets}
>  \begin{itemize}
>  \item \ref{devicenormative:Basic Facilities of a Virtio Device / Device Status Field}
>  \item \ref{devicenormative:Basic Facilities of a Virtio Device / Feature Bits}
> +\item \ref{devicenormative:Basic Facilities of a Virtio Device / Device Reset}
>  \item \ref{devicenormative:Basic Facilities of a Virtio Device / Device Configuration Space}
>  \item \ref{devicenormative:Basic Facilities of a Virtio Device / Message Framing}
>  \item \ref{devicenormative:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table}
> diff --git a/content.tex b/content.tex
> index 1ca24c13f2d0..47239b877c6c 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -51,6 +51,9 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev
>    an error from which it can't recover.
>  \end{description}
>  
> +The \field{device status} field starts out as 0, and is reinitialized to 0 by
> +the device during reset.
> +
>  \drivernormative{\subsection}{Device Status Field}{Basic Facilities of a Virtio Device / Device Status Field}
>  The driver MUST update \field{device status},
>  setting bits to indicate the completed steps of the driver
> @@ -71,7 +74,6 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev
>  \end{note}
>  
>  \devicenormative{\subsection}{Device Status Field}{Basic Facilities of a Virtio Device / Device Status Field}
> -The device MUST initialize \field{device status} to 0 upon reset.
>  
>  The device MUST NOT consume buffers or send any used buffer
>  notifications to the driver before DRIVER_OK.
> @@ -193,6 +195,26 @@ \section{Notifications}\label{sec:Basic Facilities of a Virtio Device
>  terminology. Occasionally, the term event is used to refer to
>  a notification or a receipt of a notification.
>  
> +\section{Device Reset}\label{sec:Basic Facilities of a Virtio Device / Device Reset}
> +
> +The driver may want to initiate a device reset at various times; notably,
> +it is required to do so during device initialization and device cleanup.
> +
> +The mechanism used by the driver to initiate the reset is transport specific.
> +
> +\devicenormative{\subsection}{Device Reset}{Basic Facilities of a Virtio Device / Device Reset}
> +
> +A device MUST reinitialize \field{device status} to 0 after receiving a reset.
> +
> +A device MUST NOT send notifications or interact with the queues after
> +indicating completion of the reset by reinitializing \field{device status}
> +to 0, until the driver re-initializes the device.
> +
> +\drivernormative{\subsection}{Device Reset}{Basic Facilities of a Virtio Device / Device Reset}
> +
> +The driver SHOULD consider a driver-initiated reset complete when it
> +reads \field{device status} as 0.
> +
>  \section{Device Configuration Space}\label{sec:Basic Facilities of a Virtio Device / Device Configuration Space}
>  
>  Device configuration space is generally used for rarely-changing or


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Re: [virtio-comment] [PATCH v4] clarify device reset

[Halil Pasic]

On Thu, 28 Jan 2021 14:52:35 +0100
Cornelia Huck <cohuck@redhat.com> wrote:

> Properly specify that the method for the driver to request a
> device reset is transport specific, and some action the device
> has to take.
> 
> Signed-off-by: Cornelia Huck <cohuck@redhat.com>

Reviewed-by: Halil Pasic <pasic@linux.ibm.com>

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Re: [virtio-comment] [PATCH v4] clarify device reset

[Michael S. Tsirkin]

On Thu, Jan 28, 2021 at 02:52:35PM +0100, Cornelia Huck wrote:
> Properly specify that the method for the driver to request a
> device reset is transport specific, and some action the device
> has to take.
> 
> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> ---
> 
> Stefan, Halil: I did not apply your R-b due to the amount of changes.
> 
> v3 -> v4:
>   - moved device status 're-initialize to 0' clause that is now duplicated
>     to an informal description
>   - more clarifications on when reset may be used and device requirements
>   - use \field{device status} consistently
> RFC v2 -> v3:
>   - re-worded the "must not send notifications" clause to avoid guessing
>   - added a driver conformance clause on how a driver should find out
>     when reset is complete
> RFC -> RFC v2:
>   - moved reset spec to basic facilities
> 
> ---
>  conformance.tex |  2 ++
>  content.tex     | 24 +++++++++++++++++++++++-
>  2 files changed, 25 insertions(+), 1 deletion(-)
> 
> diff --git a/conformance.tex b/conformance.tex
> index e78adfdbd283..17c390d249db 100644
> --- a/conformance.tex
> +++ b/conformance.tex
> @@ -64,6 +64,7 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets}
>  \begin{itemize}
>  \item \ref{drivernormative:Basic Facilities of a Virtio Device / Device Status Field}
>  \item \ref{drivernormative:Basic Facilities of a Virtio Device / Feature Bits}
> +\item \ref{drivernormative:Basic Facilities of a Virtio Device / Device Reset}
>  \item \ref{drivernormative:Basic Facilities of a Virtio Device / Device Configuration Space}
>  \item \ref{drivernormative:Basic Facilities of a Virtio Device / Virtqueues}
>  \item \ref{drivernormative:Basic Facilities of a Virtio Device / Message Framing}
> @@ -283,6 +284,7 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets}
>  \begin{itemize}
>  \item \ref{devicenormative:Basic Facilities of a Virtio Device / Device Status Field}
>  \item \ref{devicenormative:Basic Facilities of a Virtio Device / Feature Bits}
> +\item \ref{devicenormative:Basic Facilities of a Virtio Device / Device Reset}
>  \item \ref{devicenormative:Basic Facilities of a Virtio Device / Device Configuration Space}
>  \item \ref{devicenormative:Basic Facilities of a Virtio Device / Message Framing}
>  \item \ref{devicenormative:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table}
> diff --git a/content.tex b/content.tex
> index 1ca24c13f2d0..47239b877c6c 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -51,6 +51,9 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev
>    an error from which it can't recover.
>  \end{description}
>  
> +The \field{device status} field starts out as 0, and is reinitialized to 0 by
> +the device during reset.
> +
>  \drivernormative{\subsection}{Device Status Field}{Basic Facilities of a Virtio Device / Device Status Field}
>  The driver MUST update \field{device status},
>  setting bits to indicate the completed steps of the driver
> @@ -71,7 +74,6 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev
>  \end{note}
>  
>  \devicenormative{\subsection}{Device Status Field}{Basic Facilities of a Virtio Device / Device Status Field}
> -The device MUST initialize \field{device status} to 0 upon reset.
>  
>  The device MUST NOT consume buffers or send any used buffer
>  notifications to the driver before DRIVER_OK.

Do we want to keep the part where it starts out as 0 here?

> @@ -193,6 +195,26 @@ \section{Notifications}\label{sec:Basic Facilities of a Virtio Device
>  terminology. Occasionally, the term event is used to refer to
>  a notification or a receipt of a notification.
>  
> +\section{Device Reset}\label{sec:Basic Facilities of a Virtio Device / Device Reset}
> +
> +The driver may want to initiate a device reset at various times; notably,
> +it is required to do so during device initialization and device cleanup.
> +
> +The mechanism used by the driver to initiate the reset is transport specific.
> +
> +\devicenormative{\subsection}{Device Reset}{Basic Facilities of a Virtio Device / Device Reset}
> +
> +A device MUST reinitialize \field{device status} to 0 after receiving a reset.
> +
> +A device MUST NOT send notifications or interact with the queues after
> +indicating completion of the reset by reinitializing \field{device status}
> +to 0, until the driver re-initializes the device.
> +
> +\drivernormative{\subsection}{Device Reset}{Basic Facilities of a Virtio Device / Device Reset}
> +
> +The driver SHOULD consider a driver-initiated reset complete when it
> +reads \field{device status} as 0.
> +
>  \section{Device Configuration Space}\label{sec:Basic Facilities of a Virtio Device / Device Configuration Space}
>  
>  Device configuration space is generally used for rarely-changing or
> -- 
> 2.26.2
> 
> 
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Re: [virtio-comment] [PATCH v4] clarify device reset

[Cornelia Huck]

On Wed, 5 May 2021 09:20:45 -0400
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Thu, Jan 28, 2021 at 02:52:35PM +0100, Cornelia Huck wrote:
> > Properly specify that the method for the driver to request a
> > device reset is transport specific, and some action the device
> > has to take.
> > 
> > Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> > ---
> > 
> > Stefan, Halil: I did not apply your R-b due to the amount of changes.
> > 
> > v3 -> v4:
> >   - moved device status 're-initialize to 0' clause that is now duplicated
> >     to an informal description
> >   - more clarifications on when reset may be used and device requirements
> >   - use \field{device status} consistently
> > RFC v2 -> v3:
> >   - re-worded the "must not send notifications" clause to avoid guessing
> >   - added a driver conformance clause on how a driver should find out
> >     when reset is complete
> > RFC -> RFC v2:
> >   - moved reset spec to basic facilities
> > 
> > ---
> >  conformance.tex |  2 ++
> >  content.tex     | 24 +++++++++++++++++++++++-
> >  2 files changed, 25 insertions(+), 1 deletion(-)
> > 

(...)

> > diff --git a/content.tex b/content.tex
> > index 1ca24c13f2d0..47239b877c6c 100644
> > --- a/content.tex
> > +++ b/content.tex
> > @@ -51,6 +51,9 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev
> >    an error from which it can't recover.
> >  \end{description}
> >  
> > +The \field{device status} field starts out as 0, and is reinitialized to 0 by
> > +the device during reset.
> > +
> >  \drivernormative{\subsection}{Device Status Field}{Basic Facilities of a Virtio Device / Device Status Field}
> >  The driver MUST update \field{device status},
> >  setting bits to indicate the completed steps of the driver
> > @@ -71,7 +74,6 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev
> >  \end{note}
> >  
> >  \devicenormative{\subsection}{Device Status Field}{Basic Facilities of a Virtio Device / Device Status Field}
> > -The device MUST initialize \field{device status} to 0 upon reset.
> >  
> >  The device MUST NOT consume buffers or send any used buffer
> >  notifications to the driver before DRIVER_OK.  
> 
> Do we want to keep the part where it starts out as 0 here?

Wouldn't that duplicate the statement in the 'Device Reset' normative
section below?

> 
> > @@ -193,6 +195,26 @@ \section{Notifications}\label{sec:Basic Facilities of a Virtio Device
> >  terminology. Occasionally, the term event is used to refer to
> >  a notification or a receipt of a notification.
> >  
> > +\section{Device Reset}\label{sec:Basic Facilities of a Virtio Device / Device Reset}
> > +
> > +The driver may want to initiate a device reset at various times; notably,
> > +it is required to do so during device initialization and device cleanup.
> > +
> > +The mechanism used by the driver to initiate the reset is transport specific.
> > +
> > +\devicenormative{\subsection}{Device Reset}{Basic Facilities of a Virtio Device / Device Reset}
> > +
> > +A device MUST reinitialize \field{device status} to 0 after receiving a reset.
> > +
> > +A device MUST NOT send notifications or interact with the queues after
> > +indicating completion of the reset by reinitializing \field{device status}
> > +to 0, until the driver re-initializes the device.
> > +
> > +\drivernormative{\subsection}{Device Reset}{Basic Facilities of a Virtio Device / Device Reset}
> > +
> > +The driver SHOULD consider a driver-initiated reset complete when it
> > +reads \field{device status} as 0.
> > +
> >  \section{Device Configuration Space}\label{sec:Basic Facilities of a Virtio Device / Device Configuration Space}
> >  
> >  Device configuration space is generally used for rarely-changing or


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