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xen: do not map the same GSI twice in PVHVM guests.

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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>
This commit is contained in:
Stefano Stabellini 2012-05-21 16:54:10 +01:00 committed by Konrad Rzeszutek Wilk
parent 201a52bea9
commit 68c2c39a76
3 changed files with 10 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
arch/x86/pci/xen.c
View file

@ -64,6 +64,10 @@ static int xen_register_pirq(u32 gsi, int gsi_override, int triggering,
int shareable = 0;
char *name;
irq = xen_irq_from_gsi(gsi);
if (irq > 0)
return irq;
if (set_pirq)
pirq = gsi;

5
drivers/xen/events.c
View file

@ -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);

3
include/xen/events.h
View file

@ -103,6 +103,9 @@ int xen_irq_from_pirq(unsigned pirq);
/* 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);