xen: use percpu interrupts for IPIs and VIRQs
IPIs and VIRQs are inherently per-cpu event types, so treat them as such:
- use a specific percpu irq_chip implementation, and
- handle them with handle_percpu_irq
This makes the path for delivering these interrupts more efficient
(no masking/unmasking, no locks), and it avoid problems with attempts
to migrate them.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 72f91bf..0923ccb 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -112,6 +112,7 @@
#define VALID_EVTCHN(chn) ((chn) != 0)
static struct irq_chip xen_dynamic_chip;
+static struct irq_chip xen_percpu_chip;
/* Constructor for packed IRQ information. */
static struct irq_info mk_unbound_info(void)
@@ -403,8 +404,8 @@
if (irq < 0)
goto out;
- set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
- handle_level_irq, "ipi");
+ set_irq_chip_and_handler_name(irq, &xen_percpu_chip,
+ handle_percpu_irq, "ipi");
bind_ipi.vcpu = cpu;
if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
@@ -444,8 +445,8 @@
irq = find_unbound_irq();
- set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
- handle_level_irq, "virq");
+ set_irq_chip_and_handler_name(irq, &xen_percpu_chip,
+ handle_percpu_irq, "virq");
evtchn_to_irq[evtchn] = irq;
irq_info[irq] = mk_virq_info(evtchn, virq);
@@ -964,6 +965,16 @@
.retrigger = retrigger_dynirq,
};
+static struct irq_chip xen_percpu_chip __read_mostly = {
+ .name = "xen-percpu",
+
+ .disable = disable_dynirq,
+ .mask = disable_dynirq,
+ .unmask = enable_dynirq,
+
+ .ack = ack_dynirq,
+};
+
int xen_set_callback_via(uint64_t via)
{
struct xen_hvm_param a;