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authorStefano Stabellini <stefano.stabellini@eu.citrix.com>2012-05-21 16:54:10 +0100
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-05-21 14:11:36 -0400
commit68c2c39a76b094e9b2773e5846424ea674bf2c46 (patch)
treeb3959303806a6228adbbab234c474e16c81738ba /drivers/xen
parent201a52bea928687b7557728b176ac4f8a37d5cbd (diff)
downloadlinux-68c2c39a76b094e9b2773e5846424ea674bf2c46.tar.gz
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>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/events.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 4b33acd8ed4e..faae2f910ad2 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -611,7 +611,7 @@ static void disable_pirq(struct irq_data *data)
 	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 @@ static int find_irq_by_gsi(unsigned gsi)
 
 	return -1;
 }
+EXPORT_SYMBOL_GPL(xen_irq_from_gsi);
 
 /*
  * Do not make any assumptions regarding the relationship between the
@@ -644,7 +645,7 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
 
 	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);