Re: [PATCH] KVM: Add KVM_CAP_IRQ_ARCH capability

[Scott Wood <scottwood@freescale.com>]

On 03/14/2013 05:19:17 PM, Paul Mackerras wrote:
> On Thu, Mar 14, 2013 at 01:20:38PM -0500, Scott Wood wrote:
> > On 03/13/2013 08:20:44 PM, Paul Mackerras wrote:
> 
> > >--- a/arch/powerpc/include/asm/kvm_host.h
> > >+++ b/arch/powerpc/include/asm/kvm_host.h
> > >@@ -373,6 +373,9 @@ struct kvmppc_booke_debug_reg {
> > > struct kvm_vcpu_arch {
> > > 	ulong host_stack;
> > > 	u32 host_pid;
> > >+
> > >+	u32 intr_ctrler;
> > >+
> >
> > That abbreviation seems a bit awkward, and we should also have a
> > private-data pointer.
> >
> > How about:
> >
> > 	u32 irq_arch;
> > 	void *irq_priv;
> 
> Regarding the irq_priv - in my patchset the XICS code adds its own
> private data pointer.  That has the advantage that it can be strongly
> typed, and if it is non-NULL then I know it points to XICS data, not
> the data for some other type of controller.  As long as we are only
> going to have a small number of IRQ architectures then it's feasible
> to allow each to have its own data pointer, and we get the advantages
> of strong typing.

OK.

> > >+			switch (cap->args[0]) {
> > >+			case 0:		/* no interrupt controller */
> > >+				break;
> >
> > s/0/KVM_IRQ_ARCH_NONE/
> >
> > ...at least so that this patch makes it clear where other type ids
> > should
> > be defined.
> 
> OK, whatever.

Well, it wouldn't be good for MPIC to end up defined in one place and  
XICS in another, especially if adding a definition is how new IDs are  
allocated...

-Scott