Re: [PATCH 3/5] irqchip/gic-v2: Parse and export virtual GIC information

[Julien Grall]

On 08/02/16 18:30, Marc Zyngier wrote:
> Julien,

Hi Marc,

> On 08/02/16 16:47, Julien Grall wrote:

[...]

> > +static void __init gic_of_setup_kvm_info(struct device_node *node)
> > +{
> > +	int ret;
> > +	struct resource r;
> > +	unsigned int irq;
> > +
> > +	gic_v2_kvm_info.type = GIC_V2;
> > +
> > +	irq = irq_of_parse_and_map(node, 0);
> > +	if (!irq)
> > +		gic_v2_kvm_info.maint_irq = -1;
>
> Please don't do that. 0 *is* the value for an invalid interrupt, and
> this is what you should expose here. Same for GICv3.

I decided to use -1, because the function acpi_register_gsi is returning 
a negative value when an error occurred.

AFAICT, returning 0 would be a valid value for acpi_register_gsi.

> > +	else
> > +		gic_v2_kvm_info.maint_irq = irq;
> > +
> > +	ret = of_address_to_resource(node, 2, &r);
> > +	if (!ret) {
> > +		gic_v2_kvm_info.vctrl_base = r.start;
> > +		gic_v2_kvm_info.vctrl_size = resource_size(&r);
> > +	}
> > +
> > +	ret = of_address_to_resource(node, 3, &r);
> > +	if (!ret) {
> > +		if (!PAGE_ALIGNED(r.start))
> > +			pr_warn("GICV physical address 0x%llx not page aligned\n",
> > +				(unsigned long long)r.start);
> > +		else if (!PAGE_ALIGNED(resource_size(&r)))
> > +			pr_warn("GICV size 0x%llx not a multiple of page size 0x%lx\n",
> > +				(unsigned long long)resource_size(&r),
> > +				PAGE_SIZE);
> > +		else {
> > +			gic_v2_kvm_info.vcpu_base = r.start;
> > +			gic_v2_kvm_info.vcpu_size = resource_size(&r);
>
> This tends to make me think that this should actually be a proper
> resource, and not a set of arbitrary fields.

I will give a look.

[..]

> > @@ -1270,6 +1338,12 @@ gic_acpi_parse_madt_cpu(struct acpi_subtable_header *header,
> >   		return -EINVAL;
> >
> >   	cpu_phy_base = gic_cpu_base;
> > +	acpi_data.maint_irq = processor->vgic_interrupt;
> > +	acpi_data.maint_irq_mode = (processor->flags & ACPI_MADT_VGIC_IRQ_MODE) ?
> > +				    ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;
> > +	acpi_data.vctrl_base = processor->gich_base_address;
> > +	acpi_data.vcpu_base = processor->gicv_base_address;
> > +
>
> Maybe you can now move all the ACPI data into this acpi_data structure?
> This would allow for slightly less clutter...

Good idea, I will do it in the next version.

[...]

> Thanks,

Regards,

--
Julien Grall