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Commit aaca4964 authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge
Browse files

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: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
parent 76be97c1

drivers/xen/events.c

+15 −4
Original line number Diff line number Diff line
@@ -112,6 +112,7 @@ static inline unsigned long *cpu_evtchn_mask(int cpu) 
#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 @@ static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu) 
		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 @@ static int bind_virq_to_irq(unsigned int virq, unsigned int cpu) 


		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 @@ static struct irq_chip xen_dynamic_chip __read_mostly = { 
	.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;