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

On 09/02/16 11:23, Julien Grall wrote:

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

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Julien,

Hi Marc,

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

[...]

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+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.

No really. It either returns -EINVAL, or the result of
irq_create_fwspec_mapping, which is either going to return a virtual
interrupt number (strictly positive), or zero if the mapping was impossible.

So anything <= 0 is an error, and you can use 0 to indicate it. In
general, there is no such thing as IRQ0 (if you're not convinced, please
argue with Linus: http://yarchive.net/comp/linux/zero.html).

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+	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.

[..]

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@@ -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,

	M.
-- 
Jazz is not dead. It just smells funny...