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

From: Stefano Stabellini
Date: Mon Aug 06 2012 - 06:31:22 EST

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In reply to: Konrad Rzeszutek Wilk: "Re: [PATCH 15/24] xen/arm: receive Xen events on ARM"
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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@xxxxxxxxxxxxx>
> > ---
> > 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.

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Next message: qiang.liu: "[PATCH v6 0/8] Raid: enable talitos xor offload for improving performance"
Previous message: Tomasz Stanislawski: "Re: [PATCH 2/2] dma-buf: add helpers for attacher dma-parms"
In reply to: Konrad Rzeszutek Wilk: "Re: [PATCH 15/24] xen/arm: receive Xen events on ARM"
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