diff mbox

[15/24] xen/arm: receive Xen events on ARM

Message ID 1343316846-25860-15-git-send-email-stefano.stabellini@eu.citrix.com (mailing list archive)
State New, archived
Headers show

Commit Message

Stefano Stabellini July 26, 2012, 3:33 p.m. UTC
Compile events.c on ARM.
Parse, map and enable the IRQ to get event notifications from the device
tree (node "/xen").

On ARM Linux irqs are not enabled by default:

- call enable_percpu_irq for xen_events_irq (drivers are supposed
to call enable_irq after request_irq);

- reset the IRQ_NOAUTOEN and IRQ_NOREQUEST flags that are enabled by
default on ARM. If IRQ_NOAUTOEN is set, __setup_irq doesn't call
irq_startup, that is responsible for calling irq_unmask at startup time.
As a result event channels remain masked.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 arch/arm/xen/enlighten.c |   33 +++++++++++++++++++++++++++++++++
 arch/x86/xen/enlighten.c |    1 +
 arch/x86/xen/irq.c       |    1 +
 arch/x86/xen/xen-ops.h   |    1 -
 drivers/xen/events.c     |   18 +++++++++++++++---
 include/xen/events.h     |    2 ++
 6 files changed, 52 insertions(+), 4 deletions(-)

Comments

Konrad Rzeszutek Wilk Aug. 1, 2012, 2:44 p.m. UTC | #1
On Thu, Jul 26, 2012 at 04:33:57PM +0100, Stefano Stabellini wrote:
> Compile events.c on ARM.
> Parse, map and enable the IRQ to get event notifications from the device
> tree (node "/xen").
> 
> On ARM Linux irqs are not enabled by default:
> 
> - call enable_percpu_irq for xen_events_irq (drivers are supposed
> to call enable_irq after request_irq);
> 
> - reset the IRQ_NOAUTOEN and IRQ_NOREQUEST flags that are enabled by
> default on ARM. If IRQ_NOAUTOEN is set, __setup_irq doesn't call
> irq_startup, that is responsible for calling irq_unmask at startup time.
> As a result event channels remain masked.
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> ---
>  arch/arm/xen/enlighten.c |   33 +++++++++++++++++++++++++++++++++
>  arch/x86/xen/enlighten.c |    1 +
>  arch/x86/xen/irq.c       |    1 +
>  arch/x86/xen/xen-ops.h   |    1 -
>  drivers/xen/events.c     |   18 +++++++++++++++---
>  include/xen/events.h     |    2 ++
>  6 files changed, 52 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index 854af1e..60d6d36 100644
> --- a/arch/arm/xen/enlighten.c
> +++ b/arch/arm/xen/enlighten.c
> @@ -7,8 +7,11 @@
>  #include <xen/grant_table.h>
>  #include <xen/hvm.h>
>  #include <xen/xenbus.h>
> +#include <xen/events.h>
>  #include <asm/xen/hypervisor.h>
>  #include <asm/xen/hypercall.h>
> +#include <linux/interrupt.h>
> +#include <linux/irqreturn.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/of_irq.h>
> @@ -33,6 +36,8 @@ EXPORT_SYMBOL_GPL(xen_have_vector_callback);
>  int xen_platform_pci_unplug = XEN_UNPLUG_ALL;
>  EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
>  
> +static __read_mostly int xen_events_irq = -1;
> +
>  int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
>  			       unsigned long addr,
>  			       unsigned long mfn, int nr,
> @@ -65,6 +70,9 @@ int __init xen_guest_init(void)
>  	if (of_address_to_resource(node, 0, &res))
>  		return -EINVAL;
>  	xen_hvm_resume_frames = res.start >> PAGE_SHIFT;
> +	xen_events_irq = irq_of_parse_and_map(node, 0);
> +	pr_info("Xen support found, events_irq=%d gnttab_frame_pfn=%lx\n",
> +			xen_events_irq, xen_hvm_resume_frames);
>  	xen_domain_type = XEN_HVM_DOMAIN;
>  
>  	xen_setup_features();
> @@ -114,3 +122,28 @@ int __init xen_guest_init(void)
>  }
>  EXPORT_SYMBOL_GPL(xen_guest_init);
>  core_initcall(xen_guest_init);
> +
> +static irqreturn_t xen_arm_callback(int irq, void *arg)
> +{
> +	xen_hvm_evtchn_do_upcall();
> +	return 0;

Um, IRQ_HANDLED?

> +}
> +
> +static int __init xen_init_events(void)
> +{
> +	if (!xen_domain() || xen_events_irq < 0)
> +		return -ENODEV;
> +
> +	xen_init_IRQ();
> +
> +	if (request_percpu_irq(xen_events_irq, xen_arm_callback,
> +			"events", xen_vcpu)) {
> +		pr_err("Error requesting IRQ %d\n", xen_events_irq);
> +		return -EINVAL;
> +	}
> +
> +	enable_percpu_irq(xen_events_irq, 0);
> +
> +	return 0;
> +}
> +postcore_initcall(xen_init_events);
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index 6131d43..5a30502 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -33,6 +33,7 @@
>  #include <linux/memblock.h>
>  
>  #include <xen/xen.h>
> +#include <xen/events.h>
>  #include <xen/interface/xen.h>
>  #include <xen/interface/version.h>
>  #include <xen/interface/physdev.h>
> diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c
> index 1573376..01a4dc0 100644
> --- a/arch/x86/xen/irq.c
> +++ b/arch/x86/xen/irq.c
> @@ -5,6 +5,7 @@
>  #include <xen/interface/xen.h>
>  #include <xen/interface/sched.h>
>  #include <xen/interface/vcpu.h>
> +#include <xen/events.h>
>  
>  #include <asm/xen/hypercall.h>
>  #include <asm/xen/hypervisor.h>
> diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
> index 202d4c1..2368295 100644
> --- a/arch/x86/xen/xen-ops.h
> +++ b/arch/x86/xen/xen-ops.h
> @@ -35,7 +35,6 @@ void xen_set_pat(u64);
>  
>  char * __init xen_memory_setup(void);
>  void __init xen_arch_setup(void);
> -void __init xen_init_IRQ(void);
>  void xen_enable_sysenter(void);
>  void xen_enable_syscall(void);
>  void xen_vcpu_restore(void);
> diff --git a/drivers/xen/events.c b/drivers/xen/events.c
> index 7da65d3..9b506b2 100644
> --- a/drivers/xen/events.c
> +++ b/drivers/xen/events.c
> @@ -31,14 +31,16 @@
>  #include <linux/irqnr.h>
>  #include <linux/pci.h>
>  
> +#ifdef CONFIG_X86
>  #include <asm/desc.h>
>  #include <asm/ptrace.h>
>  #include <asm/irq.h>
>  #include <asm/idle.h>
>  #include <asm/io_apic.h>
> -#include <asm/sync_bitops.h>
>  #include <asm/xen/page.h>
>  #include <asm/xen/pci.h>
> +#endif
> +#include <asm/sync_bitops.h>
>  #include <asm/xen/hypercall.h>
>  #include <asm/xen/hypervisor.h>
>  
> @@ -50,6 +52,9 @@
>  #include <xen/interface/event_channel.h>
>  #include <xen/interface/hvm/hvm_op.h>
>  #include <xen/interface/hvm/params.h>
> +#include <xen/interface/physdev.h>
> +#include <xen/interface/sched.h>
> +#include <asm/hw_irq.h>
>  
>  /*
>   * This lock protects updates to the following mapping and reference-count
> @@ -834,6 +839,7 @@ int bind_evtchn_to_irq(unsigned int evtchn)
>  		struct irq_info *info = info_for_irq(irq);
>  		WARN_ON(info == NULL || info->type != IRQT_EVTCHN);
>  	}
> +	irq_clear_status_flags(irq, IRQ_NOREQUEST|IRQ_NOAUTOEN);

I feel that this should be its own commit by itself. I am not certain
of the implication of this on x86 and I think it deserves some explanation.


>  
>  out:
>  	mutex_unlock(&irq_mapping_update_lock);
> @@ -1377,7 +1383,9 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
>  {
>  	struct pt_regs *old_regs = set_irq_regs(regs);
>  
> +#ifdef CONFIG_X86
>  	exit_idle();
> +#endif

Doesn't exist? Or is that it does not need it?

>  	irq_enter();
>  
>  	__xen_evtchn_do_upcall();
> @@ -1786,9 +1794,9 @@ void xen_callback_vector(void)
>  void xen_callback_vector(void) {}
>  #endif
>  
> -void __init xen_init_IRQ(void)
> +void xen_init_IRQ(void)
>  {
> -	int i, rc;
> +	int i;
>  
>  	evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
>  				    GFP_KERNEL);
> @@ -1804,6 +1812,7 @@ void __init xen_init_IRQ(void)
>  
>  	pirq_needs_eoi = pirq_needs_eoi_flag;
>  
> +#ifdef CONFIG_X86
>  	if (xen_hvm_domain()) {
>  		xen_callback_vector();
>  		native_init_IRQ();
> @@ -1811,6 +1820,7 @@ void __init xen_init_IRQ(void)
>  		 * __acpi_register_gsi can point at the right function */
>  		pci_xen_hvm_init();
>  	} else {
> +		int rc;
>  		struct physdev_pirq_eoi_gmfn eoi_gmfn;
>  
>  		irq_ctx_init(smp_processor_id());
> @@ -1826,4 +1836,6 @@ void __init xen_init_IRQ(void)
>  		} else
>  			pirq_needs_eoi = pirq_check_eoi_map;
>  	}
> +#endif
>  }
> +EXPORT_SYMBOL_GPL(xen_init_IRQ);
> diff --git a/include/xen/events.h b/include/xen/events.h
> index 04399b2..c6bfe01 100644
> --- a/include/xen/events.h
> +++ b/include/xen/events.h
> @@ -109,4 +109,6 @@ 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);
>  
> +/* initialize Xen IRQ subsystem */
> +void xen_init_IRQ(void);
>  #endif	/* _XEN_EVENTS_H */
> -- 
> 1.7.2.5
Stefano Stabellini Aug. 6, 2012, 10:31 a.m. UTC | #2
On Wed, 1 Aug 2012, Konrad Rzeszutek Wilk wrote:
> On Thu, Jul 26, 2012 at 04:33:57PM +0100, Stefano Stabellini wrote:
> > Compile events.c on ARM.
> > Parse, map and enable the IRQ to get event notifications from the device
> > tree (node "/xen").
> > 
> > On ARM Linux irqs are not enabled by default:
> > 
> > - call enable_percpu_irq for xen_events_irq (drivers are supposed
> > to call enable_irq after request_irq);
> > 
> > - reset the IRQ_NOAUTOEN and IRQ_NOREQUEST flags that are enabled by
> > default on ARM. If IRQ_NOAUTOEN is set, __setup_irq doesn't call
> > irq_startup, that is responsible for calling irq_unmask at startup time.
> > As a result event channels remain masked.
> > 
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > ---
> >  arch/arm/xen/enlighten.c |   33 +++++++++++++++++++++++++++++++++
> >  arch/x86/xen/enlighten.c |    1 +
> >  arch/x86/xen/irq.c       |    1 +
> >  arch/x86/xen/xen-ops.h   |    1 -
> >  drivers/xen/events.c     |   18 +++++++++++++++---
> >  include/xen/events.h     |    2 ++
> >  6 files changed, 52 insertions(+), 4 deletions(-)
> > 
> > diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> > index 854af1e..60d6d36 100644
> > --- a/arch/arm/xen/enlighten.c
> > +++ b/arch/arm/xen/enlighten.c
> > @@ -7,8 +7,11 @@
> >  #include <xen/grant_table.h>
> >  #include <xen/hvm.h>
> >  #include <xen/xenbus.h>
> > +#include <xen/events.h>
> >  #include <asm/xen/hypervisor.h>
> >  #include <asm/xen/hypercall.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/irqreturn.h>
> >  #include <linux/module.h>
> >  #include <linux/of.h>
> >  #include <linux/of_irq.h>
> > @@ -33,6 +36,8 @@ EXPORT_SYMBOL_GPL(xen_have_vector_callback);
> >  int xen_platform_pci_unplug = XEN_UNPLUG_ALL;
> >  EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
> >  
> > +static __read_mostly int xen_events_irq = -1;
> > +
> >  int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
> >  			       unsigned long addr,
> >  			       unsigned long mfn, int nr,
> > @@ -65,6 +70,9 @@ int __init xen_guest_init(void)
> >  	if (of_address_to_resource(node, 0, &res))
> >  		return -EINVAL;
> >  	xen_hvm_resume_frames = res.start >> PAGE_SHIFT;
> > +	xen_events_irq = irq_of_parse_and_map(node, 0);
> > +	pr_info("Xen support found, events_irq=%d gnttab_frame_pfn=%lx\n",
> > +			xen_events_irq, xen_hvm_resume_frames);
> >  	xen_domain_type = XEN_HVM_DOMAIN;
> >  
> >  	xen_setup_features();
> > @@ -114,3 +122,28 @@ int __init xen_guest_init(void)
> >  }
> >  EXPORT_SYMBOL_GPL(xen_guest_init);
> >  core_initcall(xen_guest_init);
> > +
> > +static irqreturn_t xen_arm_callback(int irq, void *arg)
> > +{
> > +	xen_hvm_evtchn_do_upcall();
> > +	return 0;
> 
> Um, IRQ_HANDLED?

Yep


> > +}
> > +
> > +static int __init xen_init_events(void)
> > +{
> > +	if (!xen_domain() || xen_events_irq < 0)
> > +		return -ENODEV;
> > +
> > +	xen_init_IRQ();
> > +
> > +	if (request_percpu_irq(xen_events_irq, xen_arm_callback,
> > +			"events", xen_vcpu)) {
> > +		pr_err("Error requesting IRQ %d\n", xen_events_irq);
> > +		return -EINVAL;
> > +	}
> > +
> > +	enable_percpu_irq(xen_events_irq, 0);
> > +
> > +	return 0;
> > +}
> > +postcore_initcall(xen_init_events);
> > diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> > index 6131d43..5a30502 100644
> > --- a/arch/x86/xen/enlighten.c
> > +++ b/arch/x86/xen/enlighten.c
> > @@ -33,6 +33,7 @@
> >  #include <linux/memblock.h>
> >  
> >  #include <xen/xen.h>
> > +#include <xen/events.h>
> >  #include <xen/interface/xen.h>
> >  #include <xen/interface/version.h>
> >  #include <xen/interface/physdev.h>
> > diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c
> > index 1573376..01a4dc0 100644
> > --- a/arch/x86/xen/irq.c
> > +++ b/arch/x86/xen/irq.c
> > @@ -5,6 +5,7 @@
> >  #include <xen/interface/xen.h>
> >  #include <xen/interface/sched.h>
> >  #include <xen/interface/vcpu.h>
> > +#include <xen/events.h>
> >  
> >  #include <asm/xen/hypercall.h>
> >  #include <asm/xen/hypervisor.h>
> > diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
> > index 202d4c1..2368295 100644
> > --- a/arch/x86/xen/xen-ops.h
> > +++ b/arch/x86/xen/xen-ops.h
> > @@ -35,7 +35,6 @@ void xen_set_pat(u64);
> >  
> >  char * __init xen_memory_setup(void);
> >  void __init xen_arch_setup(void);
> > -void __init xen_init_IRQ(void);
> >  void xen_enable_sysenter(void);
> >  void xen_enable_syscall(void);
> >  void xen_vcpu_restore(void);
> > diff --git a/drivers/xen/events.c b/drivers/xen/events.c
> > index 7da65d3..9b506b2 100644
> > --- a/drivers/xen/events.c
> > +++ b/drivers/xen/events.c
> > @@ -31,14 +31,16 @@
> >  #include <linux/irqnr.h>
> >  #include <linux/pci.h>
> >  
> > +#ifdef CONFIG_X86
> >  #include <asm/desc.h>
> >  #include <asm/ptrace.h>
> >  #include <asm/irq.h>
> >  #include <asm/idle.h>
> >  #include <asm/io_apic.h>
> > -#include <asm/sync_bitops.h>
> >  #include <asm/xen/page.h>
> >  #include <asm/xen/pci.h>
> > +#endif
> > +#include <asm/sync_bitops.h>
> >  #include <asm/xen/hypercall.h>
> >  #include <asm/xen/hypervisor.h>
> >  
> > @@ -50,6 +52,9 @@
> >  #include <xen/interface/event_channel.h>
> >  #include <xen/interface/hvm/hvm_op.h>
> >  #include <xen/interface/hvm/params.h>
> > +#include <xen/interface/physdev.h>
> > +#include <xen/interface/sched.h>
> > +#include <asm/hw_irq.h>
> >  
> >  /*
> >   * This lock protects updates to the following mapping and reference-count
> > @@ -834,6 +839,7 @@ int bind_evtchn_to_irq(unsigned int evtchn)
> >  		struct irq_info *info = info_for_irq(irq);
> >  		WARN_ON(info == NULL || info->type != IRQT_EVTCHN);
> >  	}
> > +	irq_clear_status_flags(irq, IRQ_NOREQUEST|IRQ_NOAUTOEN);
> 
> I feel that this should be its own commit by itself. I am not certain
> of the implication of this on x86 and I think it deserves some explanation.

OK. It shouldn't have any effects on x86, considering that both
IRQ_NOREQUEST and IRQ_NOAUTOEN are not set there.


> >  
> >  out:
> >  	mutex_unlock(&irq_mapping_update_lock);
> > @@ -1377,7 +1383,9 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
> >  {
> >  	struct pt_regs *old_regs = set_irq_regs(regs);
> >  
> > +#ifdef CONFIG_X86
> >  	exit_idle();
> > +#endif
> 
> Doesn't exist? Or is that it does not need it?

It does not exist.
diff mbox

Patch

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 854af1e..60d6d36 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -7,8 +7,11 @@ 
 #include <xen/grant_table.h>
 #include <xen/hvm.h>
 #include <xen/xenbus.h>
+#include <xen/events.h>
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>
+#include <linux/interrupt.h>
+#include <linux/irqreturn.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
@@ -33,6 +36,8 @@  EXPORT_SYMBOL_GPL(xen_have_vector_callback);
 int xen_platform_pci_unplug = XEN_UNPLUG_ALL;
 EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
 
+static __read_mostly int xen_events_irq = -1;
+
 int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
 			       unsigned long addr,
 			       unsigned long mfn, int nr,
@@ -65,6 +70,9 @@  int __init xen_guest_init(void)
 	if (of_address_to_resource(node, 0, &res))
 		return -EINVAL;
 	xen_hvm_resume_frames = res.start >> PAGE_SHIFT;
+	xen_events_irq = irq_of_parse_and_map(node, 0);
+	pr_info("Xen support found, events_irq=%d gnttab_frame_pfn=%lx\n",
+			xen_events_irq, xen_hvm_resume_frames);
 	xen_domain_type = XEN_HVM_DOMAIN;
 
 	xen_setup_features();
@@ -114,3 +122,28 @@  int __init xen_guest_init(void)
 }
 EXPORT_SYMBOL_GPL(xen_guest_init);
 core_initcall(xen_guest_init);
+
+static irqreturn_t xen_arm_callback(int irq, void *arg)
+{
+	xen_hvm_evtchn_do_upcall();
+	return 0;
+}
+
+static int __init xen_init_events(void)
+{
+	if (!xen_domain() || xen_events_irq < 0)
+		return -ENODEV;
+
+	xen_init_IRQ();
+
+	if (request_percpu_irq(xen_events_irq, xen_arm_callback,
+			"events", xen_vcpu)) {
+		pr_err("Error requesting IRQ %d\n", xen_events_irq);
+		return -EINVAL;
+	}
+
+	enable_percpu_irq(xen_events_irq, 0);
+
+	return 0;
+}
+postcore_initcall(xen_init_events);
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 6131d43..5a30502 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -33,6 +33,7 @@ 
 #include <linux/memblock.h>
 
 #include <xen/xen.h>
+#include <xen/events.h>
 #include <xen/interface/xen.h>
 #include <xen/interface/version.h>
 #include <xen/interface/physdev.h>
diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c
index 1573376..01a4dc0 100644
--- a/arch/x86/xen/irq.c
+++ b/arch/x86/xen/irq.c
@@ -5,6 +5,7 @@ 
 #include <xen/interface/xen.h>
 #include <xen/interface/sched.h>
 #include <xen/interface/vcpu.h>
+#include <xen/events.h>
 
 #include <asm/xen/hypercall.h>
 #include <asm/xen/hypervisor.h>
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index 202d4c1..2368295 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -35,7 +35,6 @@  void xen_set_pat(u64);
 
 char * __init xen_memory_setup(void);
 void __init xen_arch_setup(void);
-void __init xen_init_IRQ(void);
 void xen_enable_sysenter(void);
 void xen_enable_syscall(void);
 void xen_vcpu_restore(void);
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 7da65d3..9b506b2 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -31,14 +31,16 @@ 
 #include <linux/irqnr.h>
 #include <linux/pci.h>
 
+#ifdef CONFIG_X86
 #include <asm/desc.h>
 #include <asm/ptrace.h>
 #include <asm/irq.h>
 #include <asm/idle.h>
 #include <asm/io_apic.h>
-#include <asm/sync_bitops.h>
 #include <asm/xen/page.h>
 #include <asm/xen/pci.h>
+#endif
+#include <asm/sync_bitops.h>
 #include <asm/xen/hypercall.h>
 #include <asm/xen/hypervisor.h>
 
@@ -50,6 +52,9 @@ 
 #include <xen/interface/event_channel.h>
 #include <xen/interface/hvm/hvm_op.h>
 #include <xen/interface/hvm/params.h>
+#include <xen/interface/physdev.h>
+#include <xen/interface/sched.h>
+#include <asm/hw_irq.h>
 
 /*
  * This lock protects updates to the following mapping and reference-count
@@ -834,6 +839,7 @@  int bind_evtchn_to_irq(unsigned int evtchn)
 		struct irq_info *info = info_for_irq(irq);
 		WARN_ON(info == NULL || info->type != IRQT_EVTCHN);
 	}
+	irq_clear_status_flags(irq, IRQ_NOREQUEST|IRQ_NOAUTOEN);
 
 out:
 	mutex_unlock(&irq_mapping_update_lock);
@@ -1377,7 +1383,9 @@  void xen_evtchn_do_upcall(struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);
 
+#ifdef CONFIG_X86
 	exit_idle();
+#endif
 	irq_enter();
 
 	__xen_evtchn_do_upcall();
@@ -1786,9 +1794,9 @@  void xen_callback_vector(void)
 void xen_callback_vector(void) {}
 #endif
 
-void __init xen_init_IRQ(void)
+void xen_init_IRQ(void)
 {
-	int i, rc;
+	int i;
 
 	evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
 				    GFP_KERNEL);
@@ -1804,6 +1812,7 @@  void __init xen_init_IRQ(void)
 
 	pirq_needs_eoi = pirq_needs_eoi_flag;
 
+#ifdef CONFIG_X86
 	if (xen_hvm_domain()) {
 		xen_callback_vector();
 		native_init_IRQ();
@@ -1811,6 +1820,7 @@  void __init xen_init_IRQ(void)
 		 * __acpi_register_gsi can point at the right function */
 		pci_xen_hvm_init();
 	} else {
+		int rc;
 		struct physdev_pirq_eoi_gmfn eoi_gmfn;
 
 		irq_ctx_init(smp_processor_id());
@@ -1826,4 +1836,6 @@  void __init xen_init_IRQ(void)
 		} else
 			pirq_needs_eoi = pirq_check_eoi_map;
 	}
+#endif
 }
+EXPORT_SYMBOL_GPL(xen_init_IRQ);
diff --git a/include/xen/events.h b/include/xen/events.h
index 04399b2..c6bfe01 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -109,4 +109,6 @@  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);
 
+/* initialize Xen IRQ subsystem */
+void xen_init_IRQ(void);
 #endif	/* _XEN_EVENTS_H */