Re: [Xen-devel] [patch xen.git xen-tip/master] xen: fix xenbus frontend build

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

M A Young wrote:
> On Tue, 5 May 2009, Randy Dunlap wrote:
>
> > From: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
> >
> > When a driver kconfig symbol =m and it selects another symbol,
> > that other symbol will also be =m (unless something else
> > causes it to be =y), so when XEN_BLKDEV_FRONTEND=m and/or
> > XEN_NETDEV_FRONTEND=m, then XEN_XENBUS_FRONTEND=m, but that
> > won't build (build error message below).  Changing
> > XEN_XENBUS_FRONTEND from a tristate to a bool makes it be
> > =y (builtin) any time that it is selected, so there is
> > no build error.
> That isn't the right solution. The real problem is that something you 
> have selected as "y" does depend on XEN_XENBUS_FRONTEND but doesn't 
> select it. Switching XEN_XENBUS_FRONTEND from tristate to bool might 
> fix your particular compile problem, but it means that the situation 
> you would get if you changed your configuration so that 
> XEN_BLKDEV_FRONTEND=n and XEN_NETDEV_FRONTEND=n (likewise any other 
> options that do select XEN_XENBUS_FRONTEND) would still broken because 
> then XEN_XENBUS_FRONTEND won't be selected at all.
> If your configuration has XEN_PCI_PASSTHROUGH=y then I posted a patch 
> for this very situation a few days ago (and it is now in xen-tip/next, 
> though wasn't yet in xen-tip/master when I last checked).
pcifront wasn't meant to go into master yet.  I'd be interested in some 
testing feedback from next.
These xenbus config options seem to be in a bit of a mess, and it would 
be nice if someone could go through and make them sane.  I think the 
ideal outcome should be:
   * the backend and frontend should be independently modular
   * they should be independently selectable (in principle we should
     allow a backend-only kernel, which I don't think is possible atm)
   * rather than having separate configs for frontends and backends,
     and a config frontend/backend xenbus, why not make the drivers
     depend on their appropriate xenbus, and directly configure them?

Anyone?
   J

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel