Re: [PATCH v2 12/13] iommu/vt-d: Add an irq_chip for posted MSIs

[Jacob Pan <jacob.jun.pan@linux.intel.com>]

Hi Kevin,

On Fri, 12 Apr 2024 09:36:10 +0000, "Tian, Kevin" <kevin.tian@intel.com>
wrote:

> > From: Jacob Pan <jacob.jun.pan@linux.intel.com>
> > Sent: Saturday, April 6, 2024 6:31 AM
> > 
> > + *
> > + * For the example below, 3 MSIs are coalesced into one CPU
> > notification. Only
> > + * one apic_eoi() is needed.
> > + *
> > + * __sysvec_posted_msi_notification()
> > + *	irq_enter();
> > + *		handle_edge_irq()
> > + *			irq_chip_ack_parent()
> > + *				dummy(); // No EOI
> > + *			handle_irq_event()
> > + *				driver_handler()
> > + *	irq_enter();
> > + *		handle_edge_irq()
> > + *			irq_chip_ack_parent()
> > + *				dummy(); // No EOI
> > + *			handle_irq_event()
> > + *				driver_handler()
> > + *	irq_enter();
> > + *		handle_edge_irq()
> > + *			irq_chip_ack_parent()
> > + *				dummy(); // No EOI
> > + *			handle_irq_event()
> > + *				driver_handler()  
> 
> typo: you added three irq_enter()'s here
right, will remove the middle two.

> 
> > + *	apic_eoi()
> > + * irq_exit()
> > + */
> > +static struct irq_chip intel_ir_chip_post_msi = {
> > +	.name			= "INTEL-IR-POST",
> > +	.irq_ack		= dummy,
> > +	.irq_set_affinity	= intel_ir_set_affinity,
> > +	.irq_compose_msi_msg	= intel_ir_compose_msi_msg,
> > +	.irq_set_vcpu_affinity	= intel_ir_set_vcpu_affinity,
> > +};  
> 
> What about putting this patch at end of the series (combining the
> change in intel_irq_remapping_alloc()) to finally enable this
> feature?
> 
> It reads slightly better to me to first get those callbacks extended
> to deal with the new mechanism (i.e. most changes in patch13)
> before using them in the new irqchip. 😊

makes sense, will do.

Thanks,

Jacob