Re: [RFC PATCH v4 18/21] x86/apic: Add a parameter for the APIC delivery mode

[Ricardo Neri]

On Sun, Jun 16, 2019 at 11:55:03AM +0200, Thomas Gleixner wrote:
> On Thu, 23 May 2019, Ricardo Neri wrote:
> >  
> >  struct irq_cfg {
> > -	unsigned int		dest_apicid;
> > -	unsigned int		vector;
> > +	unsigned int				dest_apicid;
> > +	unsigned int				vector;
> > +	enum ioapic_irq_destination_types	delivery_mode;
> 
> And how is this related to IOAPIC?

In my view, IOAPICs can also be programmed with a delivery mode. Mode
values are the same for MSI interrupts.

> I know this enum exists already, but in
> connection with MSI this does not make any sense at all.

Is the issue here the name of the enumeration?

> 
> > +
> > +		/*
> > +		 * Initialize the delivery mode of this irq to match the
> > +		 * default delivery mode of the APIC. This is useful for
> > +		 * children irq domains which want to take the delivery
> > +		 * mode from the individual irq configuration rather
> > +		 * than from the APIC.
> > +		 */
> > +		 apicd->hw_irq_cfg.delivery_mode = apic->irq_delivery_mode;
> 
> And here it's initialized from apic->irq_delivery_mode, which is an
> u32. Intuitive and consistent - NOT!

Yes, this is wrong. Then should the member in the structure above be an
u32 instead of enum ioapic_irq_destination_types?

Thanks and BR,
Ricardo