[ 097/117] xen: do not map the same GSI twice in PVHVM guests.
From: Ben Hutchings <hidden>
Date: 2012-05-28 03:30:49
Also in:
lkml
Subsystem:
pci subsystem, the rest, x86 architecture (32-bit and 64-bit), xen hypervisor interface, xen pci subsystem · Maintainers:
Bjorn Helgaas, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Juergen Gross, Stefano Stabellini
3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stefano Stabellini <redacted> commit 68c2c39a76b094e9b2773e5846424ea674bf2c46 upstream. 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. Signed-off-by: Stefano Stabellini <redacted> Signed-off-by: Konrad Rzeszutek Wilk <redacted> Signed-off-by: Ben Hutchings <redacted> --- arch/x86/pci/xen.c | 4 ++++ drivers/xen/events.c | 5 +++-- include/xen/events.h | 3 +++ 3 files changed, 10 insertions(+), 2 deletions(-)
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 @@ 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;
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 @@ 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);
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 @@ 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);