xen: do not map the same GSI twice in PVHVM guests.
PV on HVM guests map GSIs into event channels. At restore time the
event channels are resumed by restore_pirqs.
Device drivers might try to register the same GSI again through ACPI at
restore time, but the GSI has already been mapped and bound by
restore_pirqs. This patch detects these situations and avoids
mapping the same GSI multiple times.
Without this patch we get:
(XEN) irq.c:2235: dom4: pirq 23 or emuirq 28 already mapped
and waste a pirq.
CC: stable@kernel.org
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 7415aa9..56ab749 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -64,6 +64,10 @@
int shareable = 0;
char *name;
+ irq = xen_irq_from_gsi(gsi);
+ if (irq > 0)
+ return irq;
+
if (set_pirq)
pirq = gsi;
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 4b33acd..faae2f9 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -611,7 +611,7 @@
disable_dynirq(data);
}
-static int find_irq_by_gsi(unsigned gsi)
+int xen_irq_from_gsi(unsigned gsi)
{
struct irq_info *info;
@@ -625,6 +625,7 @@
return -1;
}
+EXPORT_SYMBOL_GPL(xen_irq_from_gsi);
/*
* Do not make any assumptions regarding the relationship between the
@@ -644,7 +645,7 @@
mutex_lock(&irq_mapping_update_lock);
- irq = find_irq_by_gsi(gsi);
+ irq = xen_irq_from_gsi(gsi);
if (irq != -1) {
printk(KERN_INFO "xen_map_pirq_gsi: returning irq %d for gsi %u\n",
irq, gsi);
diff --git a/include/xen/events.h b/include/xen/events.h
index 0f77370..04399b2 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -103,6 +103,9 @@
/* Return the pirq allocated to the irq. */
int xen_pirq_from_irq(unsigned irq);
+/* Return the irq allocated to the gsi */
+int xen_irq_from_gsi(unsigned gsi);
+
/* Determine whether to ignore this IRQ if it is passed to a guest. */
int xen_test_irq_shared(int irq);
