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

[Ian Campbell]

On Tue, 2013-07-02 at 11:49 +0100, Tim Deegan wrote:
> 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.

I think part of the problem here is that it is unclear who the target
audience for these drivers are.

Paul, are you intending that these drivers be only for XenServer users
or are you intending for them to be used by the broader community on a
variety of different Xen platforms?

Ian.