xen: events: refactor GSI pirq bindings functions

Following the example set by xen_allocate_pirq_msi and
xen_bind_pirq_msi_to_irq:

xen_allocate_pirq becomes xen_allocate_pirq_gsi and now only allocates
a pirq number and does not bind it.

xen_map_pirq_gsi becomes xen_bind_pirq_gsi_to_irq and binds an
existing pirq.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

3 files changed, 40 insertions, 18 deletions

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 8c4085a95ef1..e37b407a0ee8 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -50,7 +50,7 @@ static int acpi_register_gsi_xen_hvm(struct device *dev, u32 gsi,
                 name = "ioapic-level";
         }
 
-        irq = xen_map_pirq_gsi(map_irq.pirq, gsi, shareable, name);
+        irq = xen_bind_pirq_gsi_to_irq(gsi, map_irq.pirq, shareable, name);
 
         printk(KERN_DEBUG "xen: --> irq=%d, pirq=%d\n", irq, map_irq.pirq);
 
@@ -237,6 +237,7 @@ static int xen_pcifront_enable_irq(struct pci_dev *dev)
 {
         int rc;
         int share = 1;
+        int pirq;
         u8 gsi;
 
         rc = pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &gsi);
@@ -246,13 +247,21 @@ static int xen_pcifront_enable_irq(struct pci_dev *dev)
                 return rc;
         }
 
+        rc = xen_allocate_pirq_gsi(gsi);
+        if (rc < 0) {
+                dev_warn(&dev->dev, "Xen PCI: failed to allocate a PIRQ for GSI%d: %d\n",
+                         gsi, rc);
+                return rc;
+        }
+        pirq = rc;
+
         if (gsi < NR_IRQS_LEGACY)
                 share = 0;
 
-        rc = xen_allocate_pirq(gsi, share, "pcifront");
+        rc = xen_bind_pirq_gsi_to_irq(gsi, pirq, share, "pcifront");
         if (rc < 0) {
-                dev_warn(&dev->dev, "Xen PCI: failed to register GSI%d: %d\n",
-                         gsi, rc);
+                dev_warn(&dev->dev, "Xen PCI: failed to bind GSI%d (PIRQ%d) to IRQ: %d\n",
+                         gsi, pirq, rc);
                 return rc;
         }
 
@@ -309,7 +318,7 @@ int __init pci_xen_hvm_init(void)
 #ifdef CONFIG_XEN_DOM0
 static int xen_register_pirq(u32 gsi, int triggering)
 {
-        int rc, irq;
+        int rc, pirq, irq = -1;
         struct physdev_map_pirq map_irq;
         int shareable = 0;
         char *name;
@@ -325,17 +334,20 @@ static int xen_register_pirq(u32 gsi, int triggering)
                 name = "ioapic-level";
         }
 
-        irq = xen_allocate_pirq(gsi, shareable, name);
-
-        printk(KERN_DEBUG "xen: --> irq=%d\n", irq);
+        pirq = xen_allocate_pirq_gsi(gsi);
+        if (pirq < 0)
+                goto out;
 
+        irq = xen_bind_pirq_gsi_to_irq(gsi, pirq, shareable, name);
         if (irq < 0)
                 goto out;
 
+        printk(KERN_DEBUG "xen: --> pirq=%d -> irq=%d\n", pirq, irq);
+
         map_irq.domid = DOMID_SELF;
         map_irq.type = MAP_PIRQ_TYPE_GSI;
         map_irq.index = gsi;
-        map_irq.pirq = irq;
+        map_irq.pirq = pirq;
 
         rc = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq, &map_irq);
         if (rc) {
@@ -422,13 +434,18 @@ static int __init pci_xen_initial_domain(void)
 
 void __init xen_setup_pirqs(void)
 {
-        int irq;
+        int pirq, irq;
 
         pci_xen_initial_domain();
 
         if (0 == nr_ioapics) {
-                for (irq = 0; irq < NR_IRQS_LEGACY; irq++)
-                        xen_allocate_pirq(irq, 0, "xt-pic");
+                for (irq = 0; irq < NR_IRQS_LEGACY; irq++) {
+                        pirq = xen_allocate_pirq_gsi(irq);
+                        if (WARN(pirq < 0,
+                                 "Could not allocate PIRQ for legacy interrupt\n"))
+                                break;
+                        irq = xen_bind_pirq_gsi_to_irq(irq, pirq, 0, "xt-pic");
+                }
                 return;
         }
 
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index e828456777e5..a40b2a1c6255 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -568,9 +568,9 @@ static int find_irq_by_gsi(unsigned gsi)
         return -1;
 }
 
-int xen_allocate_pirq(unsigned gsi, int shareable, char *name)
+int xen_allocate_pirq_gsi(unsigned gsi)
 {
-        return xen_map_pirq_gsi(gsi, gsi, shareable, name);
+        return gsi;
 }
 
 /*
@@ -580,7 +580,8 @@ int xen_allocate_pirq(unsigned gsi, int shareable, char *name)
  * Note: We don't assign an event channel until the irq actually started
  * up.  Return an existing irq if we've already got one for the gsi.
  */
-int xen_map_pirq_gsi(unsigned pirq, unsigned gsi, int shareable, char *name)
+int xen_bind_pirq_gsi_to_irq(unsigned gsi,
+                             unsigned pirq, int shareable, char *name)
 {
         int irq = -1;
         struct physdev_irq irq_op;
diff --git a/include/xen/events.h b/include/xen/events.h
index 99a64f045732..32ebebacee7f 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -68,12 +68,16 @@ int xen_set_callback_via(uint64_t via);
 void xen_evtchn_do_upcall(struct pt_regs *regs);
 void xen_hvm_evtchn_do_upcall(void);
 
-/* Allocate an irq for a physical interrupt, given a gsi. */
-int xen_allocate_pirq(unsigned gsi, int shareable, char *name);
-int xen_map_pirq_gsi(unsigned pirq, unsigned gsi, int shareable, char *name);
+/* Allocate a pirq for a physical interrupt, given a gsi. */
+int xen_allocate_pirq_gsi(unsigned gsi);
+/* Bind a pirq for a physical interrupt to an irq. */
+int xen_bind_pirq_gsi_to_irq(unsigned gsi,
+                             unsigned pirq, int shareable, char *name);
 
 #ifdef CONFIG_PCI_MSI
+/* Allocate a pirq for a MSI style physical interrupt. */
 int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc);
+/* Bind an PSI pirq to an irq. */
 int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
                              int pirq, int vector, const char *name);
 #endif