Re: [virtio-dev] Re: [PATCH v2] content: Introduce VIRTIO_NET_F_STANDBY feature

["Samudrala, Sridhar" <sridhar.samudrala@intel.com>]

On 7/24/2018 5:43 AM, Cornelia Huck wrote:
> On Mon, 23 Jul 2018 10:02:35 -0700
> Sridhar Samudrala <sridhar.samudrala@intel.com> wrote:
>
> > VIRTIO_NET_F_STANDBY feature enables hypervisor to indicate virtio_net
> > device to act as a standby for a primary device with the same MAC address.
> >
> > Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com
> > ---
> >   content.tex | 8 ++++++++
> >   1 file changed, 8 insertions(+)
> >
> > v2: updated standby description based on Cornelia's feedback.
> >
> > diff --git a/content.tex b/content.tex
> > index be18234..b729857 100644
> > --- a/content.tex
> > +++ b/content.tex
> > @@ -2525,6 +2525,9 @@ features.
> >   
> >   \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
> >       channel.
> > +
> > +\item[VIRTIO_NET_F_STANDBY(62)] Device MAY act as a standby for a primary
> > +    device with the same MAC
> I don't think you should use MAY etc. outside a normative section, so
> s/MAY/may/

ok.


> >   \end{description}
> >   
> >   \subsubsection{Feature bit requirements}\label{sec:Device Types / Network Device / Feature bits / Feature bit requirements}
> > @@ -2636,6 +2639,11 @@ If the driver negotiates VIRTIO_NET_F_MTU, it MUST NOT transmit packets of
> >   size exceeding the value of \field{mtu} (plus low level ethernet header length)
> >   with \field{gso_type} NONE or ECN.
> >   
> > +A driver SHOULD negotiate VIRTIO_NET_F_STANDBY feature if the device offers it.
> s/VIRTIO_NET_F_STANDBY feature/the VIRTIO_NET_F_STANDBY feature/

ok.


> > +
> > +If the driver negotiates VIRTIO_NET_F_STANDBY, the device MAY act as a standby
> > +device for a primary device with the same MAC address.
> I think the first statement needs to go into a driver normative
> section, while the second needs to go into a device normative section.

ok.


> > +
> >   \subsubsection{Legacy Interface: Device configuration layout}\label{sec:Device Types / Network Device / Device configuration layout / Legacy Interface: Device configuration layout}
> >   \label{sec:Device Types / Block Device / Feature bits / Device configuration layout / Legacy Interface: Device configuration layout}
> >   When using the legacy interface, transitional devices and drivers
> I still think we need a more detailed description of how this is
> supposed to work elsewhere (i.e., outside of the normative section).
> But we can probably merge an updated version of this patch to get at
> least the feature bit reserved and documented. Thoughts?

Sure. I can submit a v3 version with the minor changes you suggested.
The detailed description of the failover mechanism can be added once qemu
patch to handle the standby feature bit is submitted and reviewed.
I am assuming someone in RH is looking into the qemu enablement patch.


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