[Xen-devel] [PATCH v4 2/7] xen: get the maximum number of pirqs from xen

[stefano.stabellini@xxxxxxxxxxxxx]

From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

Use PHYSDEVOP_get_nr_pirqs to get the maximum number of pirqs from xen.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 drivers/xen/events.c            |   30 ++++++++++++++++++++++++++----
 include/xen/interface/physdev.h |    6 ++++++
 2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 943f140..c77a44b 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -102,6 +102,7 @@ struct irq_info
 
 static struct irq_info *irq_info;
 static int *pirq_to_irq;
+static int nr_pirqs;
 
 static int *evtchn_to_irq;
 struct cpu_evtchn_s {
@@ -378,10 +379,12 @@ static int get_nr_hw_irqs(void)
        return ret;
 }
 
+/* callers of this function should make sure that PHYSDEVOP_get_nr_pirqs
+ * succeeded otherwise nr_pirqs won't hold the right value */
 static int find_unbound_pirq(void)
 {
        int i;
-       for (i = 0; i < nr_irqs; i++) {
+       for (i = nr_pirqs-1; i >= 0; i--) {
                if (pirq_to_irq[i] < 0)
                        return i;
        }
@@ -603,6 +606,13 @@ int xen_map_pirq_gsi(unsigned pirq, unsigned gsi, int 
shareable, char *name)
 
        spin_lock(&irq_mapping_update_lock);
 
+       if ((pirq > nr_pirqs) || (gsi > nr_irqs)) {
+               printk(KERN_WARNING "xen_map_pirq_gsi: %s %s is incorrect!\n",
+                       pirq > nr_pirqs ? "nr_pirqs" :"",
+                       gsi > nr_irqs ? "nr_irqs" : "");
+               goto out;
+       }
+
        irq = find_irq_by_gsi(gsi);
        if (irq != -1) {
                printk(KERN_INFO "xen_map_pirq_gsi: returning irq %d for gsi 
%u\n",
@@ -1351,14 +1361,26 @@ void xen_callback_vector(void) {}
 
 void __init xen_init_IRQ(void)
 {
-       int i;
+       int i, rc;
+       struct physdev_nr_pirqs op_nr_pirqs;
 
        cpu_evtchn_mask_p = kcalloc(nr_cpu_ids, sizeof(struct cpu_evtchn_s),
                                    GFP_KERNEL);
        irq_info = kcalloc(nr_irqs, sizeof(*irq_info), GFP_KERNEL);
 
-       pirq_to_irq = kcalloc(nr_irqs, sizeof(*pirq_to_irq), GFP_KERNEL);
-       for (i = 0; i < nr_irqs; i++)
+       rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_nr_pirqs, &op_nr_pirqs);
+       if (rc < 0) {
+               nr_pirqs = nr_irqs;
+               if (rc != -ENOSYS)
+                       printk(KERN_WARNING "PHYSDEVOP_get_nr_pirqs returned 
rc=%d\n", rc);
+       } else {
+               if (xen_pv_domain() && !xen_initial_domain())
+                       nr_pirqs = max((int)op_nr_pirqs.nr_pirqs, nr_irqs);
+               else
+                       nr_pirqs = op_nr_pirqs.nr_pirqs;
+       }
+       pirq_to_irq = kcalloc(nr_pirqs, sizeof(*pirq_to_irq), GFP_KERNEL);
+       for (i = 0; i < nr_pirqs; i++)
                pirq_to_irq[i] = -1;
 
        evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
index cd69391..fbb5883 100644
--- a/include/xen/interface/physdev.h
+++ b/include/xen/interface/physdev.h
@@ -121,6 +121,12 @@ struct physdev_op {
        } u;
 };
 
+#define PHYSDEVOP_get_nr_pirqs    22
+struct physdev_nr_pirqs {
+    /* OUT */
+    uint32_t nr_pirqs;
+};
+
 /*
  * Notify that some PIRQ-bound event channels have been unmasked.
  * ** This command is obsolete since interface version 0x00030202 and is **
-- 
1.5.6.5


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