[PATCH 37 of 38] xen: bind pirq to vector and event channel
From: Jeremy Fitzhardinge
Date:  Thu Nov 13 2008 - 14:46:38 EST
Having converting a dev+pin to a gsi, and that gsi to an irq, and
allocated a vector for the irq, we must program the IO APIC to deliver
an interrupt on a pin to the vector, so Xen can deliver it as an event
channel.
Given the pirq, we can get the gsi and vector.  We map the gsi to a
specific IO APIC's pin, and set the routing entry.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
---
 arch/x86/xen/apic.c |    4 ++--
 arch/x86/xen/pci.c  |   34 +++++++++++++++++++++++++++++++---
 2 files changed, 33 insertions(+), 5 deletions(-)
diff --git a/arch/x86/xen/apic.c b/arch/x86/xen/apic.c
--- a/arch/x86/xen/apic.c
+++ b/arch/x86/xen/apic.c
@@ -4,6 +4,7 @@
 
 #include <asm/io_apic.h>
 #include <asm/acpi.h>
+#include <asm/hw_irq.h>
 
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>
@@ -13,8 +14,7 @@
 
 static void __init xen_io_apic_init(void)
 {
-	printk("xen apic init\n");
-	dump_stack();
+	enable_IO_APIC();
 }
 
 static unsigned int xen_io_apic_read(unsigned apic, unsigned reg)
diff --git a/arch/x86/xen/pci.c b/arch/x86/xen/pci.c
--- a/arch/x86/xen/pci.c
+++ b/arch/x86/xen/pci.c
@@ -2,8 +2,10 @@
 #include <linux/acpi.h>
 #include <linux/pci.h>
 
+#include <asm/mpspec.h>
+#include <asm/io_apic.h>
+
 #include <asm/xen/hypervisor.h>
-
 #include <xen/interface/xen.h>
 #include <xen/events.h>
 
@@ -11,6 +13,31 @@
 
 #include "xen-ops.h"
 
+static void xen_set_io_apic_routing(int irq, int trigger, int polarity)
+{
+	int ioapic, ioapic_pin;
+	int vector, gsi;
+	struct IO_APIC_route_entry entry;
+
+	gsi = xen_gsi_from_irq(irq);
+	vector = xen_vector_from_irq(irq);
+
+	ioapic = mp_find_ioapic(gsi);
+	if (ioapic == -1) {
+		printk(KERN_WARNING "xen_set_ioapic_routing: irq %d gsi %d ioapic %d\n",
+			irq, gsi, ioapic);
+		return;
+	}
+
+	ioapic_pin = mp_find_ioapic_pin(ioapic, gsi);
+
+	printk(KERN_INFO "xen_set_ioapic_routing: irq %d gsi %d vector %d ioapic %d pin %d triggering %d polarity %d\n",
+		irq, gsi, vector, ioapic, ioapic_pin, trigger, polarity);
+
+	setup_ioapic_entry(ioapic, -1, &entry, ~0, trigger, polarity, vector);
+	ioapic_write_entry(ioapic, ioapic_pin, entry);
+}
+
 int xen_register_gsi(u32 gsi, int triggering, int polarity)
 {
 	int irq;
@@ -25,6 +52,9 @@
 
 	printk(KERN_DEBUG "xen: --> irq=%d\n", irq);
 
+	if (irq > 0)
+		xen_set_io_apic_routing(irq, triggering, polarity);
+
 	return irq;
 }
 
@@ -45,8 +75,6 @@
 
 		printk(KERN_INFO "xen: PCI device %s pin %d -> irq %d\n",
 		       pci_name(dev), dev->pin, irq);
-
-		/* install vector in ioapic? */
 	} else
 		printk(KERN_INFO "xen: irq enable for %s failed: rc=%d pin=%d irq=%d\n",
 			pci_name(dev), rc, dev->pin, dev->irq);
--
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