Re: [Qemu-devel] [Xen-devel] [PATCH] Citrix PV Bus device

[Paul Durrant]

> -----Original Message-----
> From: Tim Deegan [mailto:address@hidden
> Sent: 02 July 2013 11:50
> To: Paul Durrant
> Cc: Ian Campbell; address@hidden; address@hidden
> Subject: Re: [Xen-devel] [PATCH] Citrix PV Bus device
> 
> At 10:31 +0000 on 02 Jul (1372761105), Paul Durrant wrote:
> > > > Well, the WU drivers could refuse to install except as upgrade to
> > > > themselves (i.e. fail if there's any unknown driver bound to the xen
> > > > platform device, and also fail if there's _no_ driver bound).  Then the
> > > > guest admin can choose to install the drivers by hand and get automatic
> > > > updates after that.
> > >
> > > That sounds reasonable. However I thought part of the point of getting
> > > things into WU was then that they could be "inbox" (either figuratively
> > > or literally) such that they would be installed by the Windows
> > > installer. Perhaps that's a separate thing though.
> > >
> >
> > No, that is the eventual aim so I don't think the 'upgrade only'
> > options is really future-proof.
> 
> Well, you can have them install by default on platforms that want it, or
> on new enough Xen versions.  Or, even better, on new enough _windows_
> versions.
> 
> > > > XS, XC and anyone else who chooses could carry a separate patch that
> > > > changes the default to 'install if there are no drivers', signalling
> > > > over xenstore, or ACPI, or a Windows domain policy, or whatever.
> > >
> > > Right.
> > >
> >
> > Surely having a new device for the purposes of hosting Citrix PV
> > drivers is a cleaner option for opting in?
> 
> Only if it's OK that the _host_ admin has to be involved (which was the
> original objection).  Upgrade-only but hooked to the existing ID lets a
> guest admin install the drivers manually without plumbing it through
> $CLOUDPROVIDER's toolstack, and without having it appear suddenly on
> existing VMs in the dead of night.
> 

But for new VMs we *want* the drivers to download and install automatically; we 
just don't want them to do that for existing VMs.

  Paul