Re: [PATCH] xen: change XEN_PLATFORM_PCI to bool default y

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

On Wed, 21 Sep 2011, Konrad Rzeszutek Wilk wrote:
> On Wed, Sep 21, 2011 at 08:08:15PM +0100, Ian Campbell wrote:
> > On Wed, 2011-09-21 at 19:51 +0100, Konrad Rzeszutek Wilk wrote:
> > > On Wed, Sep 21, 2011 at 01:37:50PM +0100, stefano.stabellini@eu.citrix.com wrote:
> > > > From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > > > 
> > > > The xen-platform-pci module is small and for PV on HVM guests is a
> > > 
> > > How small?
> > 
> > IIRC it is single digit numbers of kb.
> > 
> > >  Does it get removed from memory if it never gets loaded?
> > > 
> > > > requirement for xenbus.
> > > 
> > > Ok, should it then have a depency on XenBus as well?
> > 
> > xenbus can't be a module (which is why allowing platform-pci to be is
> > causing problems).
> > 
> > > Linus does not like the 'default y' very much. He actually dislikes
> > > it quite much as I found when he tore Dan's behind about cleancache.
> > 
> > In particular case the option is gated on a dependency on another Xen
> > option (PVHVM) which doesn't default on. But if you do select PVHVM you
> > certainly want this option, so I think that's ok (why else would
> > 'default y' even exist?)
> > 
> > > .. so I think making it 'default n' is a better option or perhaps
> > > making it depend on some other functionality? Or perhaps just remove
> > > the tristate/bool altogether so it gets activated if XEN_PVHVM
> > > is set?
> > > 
> > > Or remove the XEN_PLATFORM_PCI config option completly and make the
> > > config files that build this driver be CONFIG_XENPVHM dependent?
> > 
> > That would work too. Even better would be to make it an invisible
> > Kconfig symbol which PVHVM just selects.
> <nods>
> Or that since you can't really do PVHVM without the platform PCI driver.
> 

Considering that we all agree that XEN_PLATFORM_PCI is needed for PVHVM,
why should we keep around the old XEN_PLATFORM_PCI config option?
I think that Konrad's idea of just using CONFIG_XEN_PVHVM to build
xen-platform-pci.o is the best one.