[virtio-dev][RFC PATCH v1 1/2] content: define what exporting a resource is

[virtio-dev][RFC PATCH v1 1/2] content: define what exporting a resource is

[David Stevens]

Define a mechanism for sharing resources between different virtio
devices.

Signed-off-by: David Stevens <stevensd@chromium.org>
---
 content.tex | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/content.tex b/content.tex
index b1ea9b9..73bd28e 100644
--- a/content.tex
+++ b/content.tex
@@ -373,6 +373,24 @@ \section{Driver Notifications}
\label{sec:Virtqueues / Driver notifications}

 \input{shared-mem.tex}

+\section{Exporting Resources}\label{sec:Basic Facilities of a Virtio
Device / Exporting Resources}
+
+When a resource created by one virtio device needs to be
+shared with a seperate virtio device, the first device can
+export the resource by generating a \field{uuid} which the
+guest can pass to the second device to identify the resource.
+
+What constitutes a resource, how to export resources, and
+how to import resources are defined by the individual device
+types. The generation method of a \field{uuid} is dependent
+upon the implementation of the exporting device.
+
+Whether a particular exported resource can be imported into
+a device is dependent upon the implementations of the exporting
+and importing devices. Generally speaking, the guest should
+have some knowledge of the host configuration before trying to
+use exported resources.
+
 \chapter{General Initialization And Device
Operation}\label{sec:General Initialization And Device Operation}

 We start with an overview of device initialization, then expand on the
-- 
2.24.1.735.g03f4e72817-goog

Re: [virtio-dev][RFC PATCH v1 1/2] content: define what exporting a resource is

[Gerd Hoffmann]

On Wed, Jan 08, 2020 at 06:01:58PM +0900, David Stevens wrote:
> Define a mechanism for sharing resources between different virtio
> devices.
> 
> Signed-off-by: David Stevens <stevensd@chromium.org>
> ---
>  content.tex | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/content.tex b/content.tex
> index b1ea9b9..73bd28e 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -373,6 +373,24 @@ \section{Driver Notifications}
> \label{sec:Virtqueues / Driver notifications}
> 
>  \input{shared-mem.tex}
> 
> +\section{Exporting Resources}\label{sec:Basic Facilities of a Virtio
> Device / Exporting Resources}
> +
> +When a resource created by one virtio device needs to be
> +shared with a seperate virtio device, the first device can
> +export the resource by generating a \field{uuid} which the
> +guest can pass to the second device to identify the resource.
> +
> +What constitutes a resource, how to export resources, and
> +how to import resources are defined by the individual device
> +types. The generation method of a \field{uuid} is dependent
> +upon the implementation of the exporting device.
> +
> +Whether a particular exported resource can be imported into
> +a device is dependent upon the implementations of the exporting
> +and importing devices. Generally speaking, the guest should
> +have some knowledge of the host configuration before trying to
> +use exported resources.

Hmm, I'd suggest to move the whole thing into the virtio-gpu section.
There is no such thing as a "resource" in general virtio context ...

cheers,
  Gerd

Re: [virtio-dev][RFC PATCH v1 1/2] content: define what exporting a resource is

[David Stevens]

[-- Attachment #1: Type: text/plain, Size: 587 bytes --]

>
> Hmm, I'd suggest to move the whole thing into the virtio-gpu section.
> There is no such thing as a "resource" in general virtio context ...
>

If this is moved into the virtio-gpu section, then any device type that
imports resources will have to refer to something defined by the GPU device
type. This would make the GPU device type a sort of special device type
that isn't just a leaf node of the spec. I think it's better to define
'resource' as a top level concept for virtio devices, even if the specifics
of what a 'resource' is are defined by individual device types.

-David

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Re: [virtio-dev][RFC PATCH v1 1/2] content: define what exporting a resource is

[Gerd Hoffmann]

  Hi,

> that isn't just a leaf node of the spec. I think it's better to define
> 'resource' as a top level concept for virtio devices, even if the specifics
> of what a 'resource' is are defined by individual device types.

Your patch doesn't define what a resource is though.  It only refers to
something it calls 'resource' ...

cheers,
  Gerd

Re: [virtio-dev][RFC PATCH v1 1/2] content: define what exporting a resource is

[David Stevens]

> > that isn't just a leaf node of the spec. I think it's better to define
> > 'resource' as a top level concept for virtio devices, even if the specifics
> > of what a 'resource' is are defined by individual device types.
>
> Your patch doesn't define what a resource is though.  It only refers to
> something it calls 'resource' ...

Reading it again, what I wrote was a little ambiguous. Stating things
more clearly, the top level defines an 'exported resource' as a
'resource' associated with a uuid for the purpose of sharing between
different virtio devices. It leaves the definition of what constitutes
a 'resource' to individual device types. Perhaps it would be better to
use 'object' or something instead of 'resource', to avoid the
collision with virtio-gpu resources.

-David