xen: remap GSIs as pirqs when running as initial domain

Implement xen_register_gsi to setup the correct triggering and polarity
properties of a gsi.
Implement xen_register_pirq to register a particular gsi as pirq and
receive interrupts as events.
Call xen_setup_pirqs to register all the legacy ISA irqs as pirqs.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

2 files changed, 142 insertions, 0 deletions

diff --git a/arch/x86/include/asm/xen/pci.h b/arch/x86/include/asm/xen/pci.h
index f89a42aff284..2329b3eaf8d3 100644
--- a/arch/x86/include/asm/xen/pci.h
+++ b/arch/x86/include/asm/xen/pci.h
@@ -13,6 +13,13 @@ static inline int pci_xen_hvm_init(void)
         return -1;
 }
 #endif
+#if defined(CONFIG_XEN_DOM0)
+void __init xen_setup_pirqs(void);
+#else
+static inline void __init xen_setup_pirqs(void)
+{
+}
+#endif
 
 #if defined(CONFIG_PCI_MSI)
 #if defined(CONFIG_PCI_XEN)
diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index b5bd6420851e..dd0b5fdb27b9 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -257,3 +257,138 @@ int __init pci_xen_hvm_init(void)
 #endif
         return 0;
 }
+
+#ifdef CONFIG_XEN_DOM0
+static int xen_register_pirq(u32 gsi, int triggering)
+{
+        int rc, irq;
+        struct physdev_map_pirq map_irq;
+        int shareable = 0;
+        char *name;
+
+        if (!xen_pv_domain())
+                return -1;
+
+        if (triggering == ACPI_EDGE_SENSITIVE) {
+                shareable = 0;
+                name = "ioapic-edge";
+        } else {
+                shareable = 1;
+                name = "ioapic-level";
+        }
+
+        irq = xen_allocate_pirq(gsi, shareable, name);
+
+        printk(KERN_DEBUG "xen: --> irq=%d\n", irq);
+
+        if (irq < 0)
+                goto out;
+
+        map_irq.domid = DOMID_SELF;
+        map_irq.type = MAP_PIRQ_TYPE_GSI;
+        map_irq.index = gsi;
+        map_irq.pirq = irq;
+
+        rc = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq, &map_irq);
+        if (rc) {
+                printk(KERN_WARNING "xen map irq failed %d\n", rc);
+                return -1;
+        }
+
+out:
+        return irq;
+}
+
+static int xen_register_gsi(u32 gsi, int triggering, int polarity)
+{
+        int rc, irq;
+        struct physdev_setup_gsi setup_gsi;
+
+        if (!xen_pv_domain())
+                return -1;
+
+        printk(KERN_DEBUG "xen: registering gsi %u triggering %d polarity %d\n",
+                        gsi, triggering, polarity);
+
+        irq = xen_register_pirq(gsi, triggering);
+
+        setup_gsi.gsi = gsi;
+        setup_gsi.triggering = (triggering == ACPI_EDGE_SENSITIVE ? 0 : 1);
+        setup_gsi.polarity = (polarity == ACPI_ACTIVE_HIGH ? 0 : 1);
+
+        rc = HYPERVISOR_physdev_op(PHYSDEVOP_setup_gsi, &setup_gsi);
+        if (rc == -EEXIST)
+                printk(KERN_INFO "Already setup the GSI :%d\n", gsi);
+        else if (rc) {
+                printk(KERN_ERR "Failed to setup GSI :%d, err_code:%d\n",
+                                gsi, rc);
+        }
+
+        return irq;
+}
+
+static __init void xen_setup_acpi_sci(void)
+{
+        int rc;
+        int trigger, polarity;
+        int gsi = acpi_sci_override_gsi;
+
+        if (!gsi)
+                return;
+
+        rc = acpi_get_override_irq(gsi, &trigger, &polarity);
+        if (rc) {
+                printk(KERN_WARNING "xen: acpi_get_override_irq failed for acpi"
+                                " sci, rc=%d\n", rc);
+                return;
+        }
+        trigger = trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE;
+        polarity = polarity ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
+        
+        printk(KERN_INFO "xen: sci override: global_irq=%d trigger=%d "
+                        "polarity=%d\n", gsi, trigger, polarity);
+
+        gsi = xen_register_gsi(gsi, trigger, polarity);
+        printk(KERN_INFO "xen: acpi sci %d\n", gsi);
+
+        return;
+}
+
+static int acpi_register_gsi_xen(struct device *dev, u32 gsi,
+                                 int trigger, int polarity)
+{
+        return xen_register_gsi(gsi, trigger, polarity);
+}
+
+static int __init pci_xen_initial_domain(void)
+{
+        xen_setup_acpi_sci();
+        __acpi_register_gsi = acpi_register_gsi_xen;
+
+        return 0;
+}
+
+void __init xen_setup_pirqs(void)
+{
+        int irq;
+
+        pci_xen_initial_domain();
+
+        if (0 == nr_ioapics) {
+                for (irq = 0; irq < NR_IRQS_LEGACY; irq++)
+                        xen_allocate_pirq(irq, 0, "xt-pic");
+                return;
+        }
+
+        /* Pre-allocate legacy irqs */
+        for (irq = 0; irq < NR_IRQS_LEGACY; irq++) {
+                int trigger, polarity;
+
+                if (acpi_get_override_irq(irq, &trigger, &polarity) == -1)
+                        continue;
+
+                xen_register_pirq(irq,
+                        trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE);
+        }
+}
+#endif