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Commit 68c2c39a authored by Stefano Stabellini's avatar Stefano Stabellini Committed by Konrad Rzeszutek Wilk
Browse files

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: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 201a52be

arch/x86/pci/xen.c

+4 −0
Original line number Diff line number Diff line
@@ -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;

drivers/xen/events.c

+3 −2
Original line number Diff line number Diff line
@@ -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);

include/xen/events.h

+3 −0
Original line number Diff line number Diff line
@@ -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);