Re: [GIT PULL 3/6] KVM: arm: use GIC support unconditionally

[Arnd Bergmann <arnd@arndb.de>]

On Wednesday 21 October 2015 15:58:44 Christoffer Dall wrote:
> On Wed, Oct 21, 2015 at 03:45:20PM +0200, Arnd Bergmann wrote:
> > On Tuesday 20 October 2015 15:51:05 Paolo Bonzini wrote:
> > > Should this be "select" or "depends on"? Not a blocker, can always be fixed in 4.4.
> > 
> > We have lots of 'select ARM_GIC' in the tree for platforms that use one, using
> > 'depends on' will limit KVM support to being available only if at least one
> > of them is being used.
> > 
> > The only platform I can think of that uses ARMv7ve without actually having
> > a GIC is BCM2836 (Raspberry Pi 2). Can we actually run KVM on a platform
> > like that? If so, 'depends on' might be better, otherwise let's stay with
> > 'select'.
> 
> Yes you can, just without the VGIC and the timer - you have to emulate
> that in userspace.  Samsung also has a broken platform where they
> integrated things incorrectly, so you cannot use the VGIC, but that
> platform support is out of tree, so I can't see if it uses the GIC in
> general or not.

Ok, my patch should be fine then.
 
> I'm a bit confused why using 'depends on' in this case helps anythign?
> 
> (I know, I suck at dealing with the config system)

Generally speaking, 'select' causes more problems than 'depends on',
in particular when you get conflicting requirements (A selects B,
B depends on C, but A can be enabled without C).

However, symbols that only have 'select' and no 'depends on', and also
are not user-visible, are not problematic. This is the case here.

	Arnd