xen: use PHYSDEVOP_get_free_pirq to implement find_unbound_pirq
Use the new hypercall PHYSDEVOP_get_free_pirq to ask Xen to allocate a
pirq. Remove the unsupported PHYSDEVOP_get_nr_pirqs hypercall to get the
amount of pirq available.
This fixes find_unbound_pirq that otherwise would return a number
starting from nr_irqs that might very well be out of range in Xen.
The symptom of this bug is that when you passthrough an MSI capable pci
device to a PV on HVM guest, Linux would fail to enable MSIs on the
device.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 2811bb9..7ab43c3 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -105,7 +105,6 @@
static struct irq_info *irq_info;
static int *pirq_to_irq;
-static int nr_pirqs;
static int *evtchn_to_irq;
struct cpu_evtchn_s {
@@ -385,12 +384,17 @@
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)
+static int find_unbound_pirq(int type)
{
- int i;
- for (i = nr_pirqs-1; i >= 0; i--) {
+ int rc, i;
+ struct physdev_get_free_pirq op_get_free_pirq;
+ op_get_free_pirq.type = type;
+
+ rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_free_pirq, &op_get_free_pirq);
+ if (!rc)
+ return op_get_free_pirq.pirq;
+
+ for (i = 0; i < nr_irqs; i++) {
if (pirq_to_irq[i] < 0)
return i;
}
@@ -611,10 +615,10 @@
spin_lock(&irq_mapping_update_lock);
- if ((pirq > nr_pirqs) || (gsi > nr_irqs)) {
+ if ((pirq > nr_irqs) || (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" : "");
+ pirq > nr_irqs ? "pirq" :"",
+ gsi > nr_irqs ? "gsi" : "");
goto out;
}
@@ -672,7 +676,7 @@
if (*irq == -1)
goto out;
- *pirq = find_unbound_pirq();
+ *pirq = find_unbound_pirq(MAP_PIRQ_TYPE_MSI);
if (*pirq == -1)
goto out;
@@ -1506,26 +1510,17 @@
void __init xen_init_IRQ(void)
{
- int i, rc;
- struct physdev_nr_pirqs op_nr_pirqs;
+ int i;
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);
- 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++)
+ /* We are using nr_irqs as the maximum number of pirq available but
+ * that number is actually chosen by Xen and we don't know exactly
+ * what it is. Be careful choosing high pirq numbers. */
+ pirq_to_irq = kcalloc(nr_irqs, sizeof(*pirq_to_irq), GFP_KERNEL);
+ for (i = 0; i < nr_irqs; i++)
pirq_to_irq[i] = -1;
evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),