Re: [virtio-comment] TAB Comments on Virtual I/O Device (VIRTIO) Version 1.0

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

On Thu, Feb 13, 2014 at 05:01:24PM +1030, Rusty Russell wrote:
> Patrick Durusau <patrick@durusau.net> writes:
> > TAB-556	Conformance targets
> > 
> > 	After reading 2.2.1 Legacy Interface, again, I have a suggestion
> > 	for conformance targets in section 9 (subject to my getting this
> > 	wrong): 1. Non-Transitional Device - enumerate which sections of
> > 	normative text I MUST conform to in order to have a
> > 	Non-Transitional Device. 2. Non-Transitional Driver - enumerate
> > 	which sections of normative text I MUST conform to in order to
> > 	have a Non-Transitional Driver. 3. #1 plus ?? = Transitional
> > 	Device. 4. #2 plus ?? = Transitional Driver with the
> > 	sub-numbering under 1 - 4 specifying the details of
> > 	conformance. Yes?
> 
> I originally wanted to make all the legacy sections non-normative, and
> thus avoid any MUSTs in there.  It's a bit weird, becuase legacy systems
> our outside the scope of the current standard, but we really do want to
> be kind for people in transition.
> 
> I think Michael had objections to this, though.  So here's my
> compromise:

Acked-by: Michael S. Tsirkin <mst@redhat.com>

Let's start opening issues to track comments, OK?

> diff --git a/conformance.tex b/conformance.tex
> index 0e8b321..d564392 100644
> --- a/conformance.tex
> +++ b/conformance.tex
> @@ -6,3 +6,54 @@
>  An implementation conforms to this specification if it satisfies
>  all of the MUST or REQUIRED level requirements defined within
>  this specification.
> +
> +In particular, a device does not need to support legacy drivers, nor
> +a driver support legacy devices to confirm to this specification,
> +ie. non-transitional drivers and devices are fine.  (In fact, the only
> +awareness such non-transitional implementations need that legacy
> +systems ever existed is specified in \ref{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Device Initialization / Non-transitional Device With Legacy Driver}
> +for PCI device implementations).
> +
> +All requirements for such transitional devices and drivers are
> +explicitly noted as such, and contained within sections named ``Legacy
> +Interfaces''.  These sections also function to assuage the guilt of
> +the committee for breaking existing deployments:
> +
> +\begin{itemize}
> +\item Section \ref{sec:Basic Facilities of a Virtio Device / Feature Bits / Legacy Interface: A Note on transitions from earlier drafts}
> +\item Section \ref{sec:Basic Facilities of a Virtio Device / Device Configuration Space / Legacy Interface: A Note on Configuration Space endian-ness}
> +\item Section \ref{sec:Basic Facilities of a Virtio Device / Device Configuration Space / Legacy Interface: Device Configuration Space}
> +\item Section \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Legacy Interfaces: A Note on Virtqueue Layout}
> +\item Section \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Legacy Interfaces: A Note on Virtqueue Endianness}
> +\item Section \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Message Framing / Legacy Interface: Message Framing}
> +\item Section \ref{sec:General Initialization And Device Operation / Device Initialization / Legacy Interface: Device Initialization}
> +\item Section \ref{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Discovery / Legacy Interfaces: A Note on PCI Device Discovery}
> +\item Section \ref{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Legacy Interfaces: A Note on PCI Device Layout}
> +\item Section \ref{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Device Initialization / Virtio Device Configuration Layout Detection / Legacy Interface: A Note on Device Layout Detection}
> +\item Section \ref{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Device Initialization / Virtqueue Configuration / Legacy Interface: A Note on Virtqueue Configuration}
> +\item Section \ref{sec:Virtio Transport Options / Virtio Over MMIO / Legacy interface}
> +\item Section \ref{sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Setting the Virtio Revision / Legacy Interfaces: A Note on Setting the Virtio Revision}
> +\item Section \ref{sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Configuring a Virtqueue / Legacy Interface: A Note on Configuring a Virtqueue}
> +\item Section \ref{sec:Virtio Transport Options / Virtio over channel I/O / Device Operation / Host->Guest Notification / Legacy Interfaces: A Note on Host->Guest Notification}
> +\item Section \ref{sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Setting Up Indicators / Legacy Interfaces: A Note on Setting Up Indicators}
> +\item Section \ref{sec:Device Types / Network Device / Feature bits / Legacy Interface: Feature bits}
> +\item Section \ref{sec:Device Types / Network Device / Device configuration layout / Legacy Interface: Device configuration layout}
> +\item Section \ref{sec:Device Types / Network Device / Device Operation / Legacy Interface: Device Operation}
> +\item Section \ref{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Setting MAC Address Filtering / Legacy Interface: Setting MAC Address Filtering}
> +\item Section \ref{sec:Device Types / Network Device / Device Operation / Control Virtqueue / VLAN Filtering / Legacy Interface: VLAN Filtering}
> +\item Section \ref{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Automatic receive steering in multiqueue mode / Legacy Interface: Automatic receive steering in multiqueue mode}
> +\item Section \ref{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Offloads State Configuration / Setting Offloads State / Legacy Interface: Setting Offloads State}
> +\item Section \ref{sec:Device Types / Block Device / Feature bits / Legacy Interface: Feature bits}
> +\item Section \ref{sec:Device Types / Block Device / Feature bits / Device configuration layout / Legacy Interface: Device configuration layout}
> +\item Section \ref{sec:Device Types / Block Device / Device Initialization / Legacy Interface: Device Initialization}
> +\item Section \ref{sec:Device Types / Block Device / Device Operation / Legacy Interface: Device Operation}
> +\item Section \ref{sec:Device Types / Console Device / Device configuration layout / Legacy Interface: Device configuration layout}
> +\item Section \ref{sec:Device Types / Console Device / Device Operation / Legacy Interface: Device Operation}
> +\item Section \ref{sec:Device Types / Memory Balloon Device / Device configuration layout / Legacy Interface: Device configuration layout}
> +\item Section \ref{sec:Device Types / Memory Balloon Device / Device Operation / Memory Statistics / Legacy Interface: Memory Statistics}
> +\item Section \ref{sec:Device Types / SCSI Host Device / Device configuration layout / Legacy Interface: Device configuration layout}
> +\item Section \ref{sec:Device Types / SCSI Host Device / Device Operation / Device Operation: Request Queues / Legacy Interface: Device Operation: Request Queues}
> +\item Section \ref{sec:Device Types / SCSI Host Device / Device Operation / Device Operation: controlq / Legacy Interface: Device Operation: controlq}
> +\item Section \ref{sec:Device Types / SCSI Host Device / Device Operation / Device Operation: eventq / Legacy Interface: Device Operation: eventq}
> +\item Section \ref{sec:Reserved Feature Bits / Legacy Interface: Reserved Feature Bits}
> +\end{itemize}