Re: [virtio] [PATCH 3/4] ccw: virtio revision vs. virtio feature bits

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Oct 31, 2014 at 03:26:18PM +0100, Cornelia Huck wrote:
> We don't want the VERSION_1 feature bit unless at least revision 1
> has been negotiated. Make this a requirement.
> 
> VIRTIO-119
> 
> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

Sorry about the delay in response.
I think I disagree with this one.

I think this discusses how transitional devices work when
using the legacy interface?
In that case, this needs to go into a separate section,
explicitly labelled "legacy".
Looking into this deeper, how do devices "not accept"
bits when using a legacy interface?

Also, the wording here seems wrong to me.



> ---
>  conformance.tex |    1 +
>  content.tex     |    8 ++++++++
>  2 files changed, 9 insertions(+)
> 
> diff --git a/conformance.tex b/conformance.tex
> index 033481f..b10ce96 100644
> --- a/conformance.tex
> +++ b/conformance.tex
> @@ -182,6 +182,7 @@ A Channel I/O device MUST conform to the following normative statements:
>  \item \ref{devicenormative:Virtio Transport Options / Virtio over channel I/O / Basic Concepts}
>  \item \ref{devicenormative:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Setting the Virtio Revision}
>  \item \ref{devicenormative:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Configuring a Virtqueue}
> +\item \ref{devicenormative:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Handling Device Features}
>  \item \ref{devicenormative:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Setting Up Indicators / Setting Up Two-Stage Queue Indicators}
>  \item \ref{devicenormative:Virtio Transport Options / Virtio over channel I/O / Device Operation / Host->Guest Notification / Notification via Adapter I/O Interrupts}
>  \item \ref{devicenormative:Virtio Transport Options / Virtio over channel I/O / Device Operation / Guest->Host Notification}
> diff --git a/content.tex b/content.tex
> index 6968583..38ae49e 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -2656,6 +2656,14 @@ For communicating its supported features to the device, the driver
>  uses the CCW_CMD_WRITE_FEAT command, denoting a \field{features}/\field{index}
>  combination.
>  
> +\devicenormative{\paragraph}{Handling Device Features}{Virtio Transport Options / Virtio over channel I/O / Device Initialization / Handling Device Features}
> +
> +The device MUST NOT offer VIRTIO_F_VERSION_1 if not at least revision 1 has
> +been negociated.
> +
> +The device MUST NOT accept VIRTIO_F_VERSION_1 if not at least revision 1 has
> +been negociated.
> +
>  \subsubsection{Device Configuration}\label{sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Device Configuration}
>  
>  The device's configuration space is located in host memory.
> -- 
> 1.7.9.5
> 
> 
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