[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH] xen: events: do not unmask polled ipis on restore.
The Xen PV spinlock backend attempts to setup an IPI to IRQ binding which is only to be used via xen_poll_irq rather received directly. Unfortunately restore_cpu_ipis unconditionally unmasks each IPI leading to: [ 21.970432] ------------[ cut here ]------------ [ 21.970432] kernel BUG at /local/scratch/ianc/devel/kernels/linux-2.6/arch/x86/xen/spinlock.c:343! [ 21.970432] invalid opcode: 0000 [#1] SMP [ 21.970432] last sysfs file: /sys/devices/virtual/net/lo/operstate [ 21.970432] Modules linked in: [ 21.970432] [ 21.970432] Pid: 0, comm: swapper Not tainted (2.6.32.24-x86_32p-xen-01034-g787c727 #34) [ 21.970432] EIP: 0061:[<c102e209>] EFLAGS: 00010046 CPU: 3 [ 21.970432] EIP is at dummy_handler+0x3/0x7 [ 21.970432] EAX: 0000021c EBX: dfc16880 ECX: 0000001a EDX: 00000000 [ 21.970432] ESI: dfc02c00 EDI: 00000001 EBP: dfc47e10 ESP: dfc47e10 [ 21.970432] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0069 [ 21.970432] Process swapper (pid: 0, ti=dfc46000 task=dfc39440 task.ti=dfc46000) [ 21.970432] Stack: [ 21.970432] dfc47e30 c10a39f0 0000021c 00000000 00000000 dfc16880 0000021c 00000001 [ 21.970432] <0> dfc47e40 c10a4f08 0000021c 00000000 dfc47e78 c12240a7 c1839284 c1839284 [ 21.970432] <0> 00000200 00000000 00000000 f5720000 c1f3d028 c1f3d02c 00000180 dfc47e90 [ 21.970432] Call Trace: [ 21.970432] [<c10a39f0>] ? handle_IRQ_event+0x5f/0x122 [ 21.970432] [<c10a4f08>] ? handle_percpu_irq+0x2f/0x55 [ 21.970432] [<c12240a7>] ? __xen_evtchn_do_upcall+0xdb/0x15f [ 21.970432] [<c122481e>] ? xen_evtchn_do_upcall+0x20/0x30 [ 21.970432] [<c1030d47>] ? xen_do_upcall+0x7/0xc [ 21.970432] [<c102007b>] ? apic_reg_read+0xd3/0x22d [ 21.970432] [<c1002227>] ? hypercall_page+0x227/0x1005 [ 21.970432] [<c102d30b>] ? xen_force_evtchn_callback+0xf/0x14 [ 21.970432] [<c102da7c>] ? check_events+0x8/0xc [ 21.970432] [<c102da3b>] ? xen_irq_enable_direct_end+0x0/0x1 [ 21.970432] [<c105e485>] ? finish_task_switch+0x62/0xba [ 21.970432] [<c14e3f84>] ? schedule+0x808/0x89d [ 21.970432] [<c1084dc5>] ? hrtimer_start_expires+0x1a/0x22 [ 21.970432] [<c1085154>] ? tick_nohz_restart_sched_tick+0x15a/0x162 [ 21.970432] [<c102f43a>] ? cpu_idle+0x6d/0x6f [ 21.970432] [<c14db29e>] ? cpu_bringup_and_idle+0xd/0xf [ 21.970432] Code: 5d 0f 95 c0 0f b6 c0 c3 55 66 83 78 02 00 89 e5 5d 0f 95 c0 0f b6 c0 c3 55 b2 01 86 10 31 c0 84 d2 89 e5 0f 94 c0 5d c3 55 89 e5 <0f> 0b eb fe 55 80 3d 4c ce 84 c1 00 89 e5 57 56 89 c6 53 74 15 [ 21.970432] EIP: [<c102e209>] dummy_handler+0x3/0x7 SS:ESP 0069:dfc47e10 [ 21.970432] ---[ end trace c0b71f7e12cf3011 ]--- Add a new bind function which explicitly binds a polled-only IPI and track this state in the event channel core so that we can do the right thing on restore. Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx> --- arch/x86/xen/spinlock.c | 16 +++------------- drivers/xen/events.c | 45 ++++++++++++++++++++++++++++++++++++++++----- include/xen/events.h | 4 ++++ 3 files changed, 47 insertions(+), 18 deletions(-) diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c index 36a5141..09655ca 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -338,29 +338,19 @@ static void xen_spin_unlock(struct raw_spinlock *lock) xen_spin_unlock_slow(xl); } -static irqreturn_t dummy_handler(int irq, void *dev_id) -{ - BUG(); - return IRQ_HANDLED; -} - void __cpuinit xen_init_lock_cpu(int cpu) { int irq; const char *name; name = kasprintf(GFP_KERNEL, "spinlock%d", cpu); - irq = bind_ipi_to_irqhandler(XEN_SPIN_UNLOCK_VECTOR, + irq = bind_polled_ipi_to_irq(XEN_SPIN_UNLOCK_VECTOR, cpu, - dummy_handler, IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING, - name, - NULL); + name); - if (irq >= 0) { - disable_irq(irq); /* make sure it's never delivered */ + if (irq >= 0) per_cpu(lock_kicker_irq, cpu) = irq; - } printk("cpu %d spinlock event irq %d\n", cpu, irq); } diff --git a/drivers/xen/events.c b/drivers/xen/events.c index 7b29ae1..f8b53b5 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -94,7 +94,10 @@ struct irq_info union { unsigned short virq; - enum ipi_vector ipi; + struct { + enum ipi_vector vector; + unsigned char polled; + } ipi; struct { unsigned short gsi; unsigned char vector; @@ -148,7 +151,7 @@ static struct irq_info mk_evtchn_info(unsigned short evtchn) static struct irq_info mk_ipi_info(unsigned short evtchn, enum ipi_vector ipi) { return (struct irq_info) { .type = IRQT_IPI, .evtchn = evtchn, - .cpu = 0, .u.ipi = ipi }; + .cpu = 0, .u.ipi.vector = ipi, .u.ipi.polled = 0 }; } static struct irq_info mk_virq_info(unsigned short evtchn, unsigned short virq) @@ -191,7 +194,7 @@ static enum ipi_vector ipi_from_irq(unsigned irq) BUG_ON(info == NULL); BUG_ON(info->type != IRQT_IPI); - return info->u.ipi; + return info->u.ipi.vector; } static unsigned virq_from_irq(unsigned irq) @@ -971,6 +974,33 @@ int bind_ipi_to_irqhandler(enum ipi_vector ipi, return irq; } + +static irqreturn_t polled_ipi_handler(int irq, void *dev_id) +{ + BUG(); + return IRQ_HANDLED; +} + +int bind_polled_ipi_to_irq(enum ipi_vector ipi, + unsigned int cpu, + unsigned long irqflags, + const char *devname) +{ + int irq, retval; + + irq = bind_ipi_to_irqhandler(ipi, cpu, polled_ipi_handler, + irqflags, devname, NULL); + if (irq < 0) + return irq; + + info_for_irq(irq)->u.ipi.polled = 1; + + disable_irq(irq); /* make sure it's never delivered */ + + return irq; + +} + void unbind_from_irqhandler(unsigned int irq, void *dev_id) { free_irq(irq, dev_id); @@ -1290,6 +1320,7 @@ static void restore_cpu_virqs(unsigned int cpu) static void restore_cpu_ipis(unsigned int cpu) { struct evtchn_bind_ipi bind_ipi; + int polled; int ipi, irq, evtchn; for (ipi = 0; ipi < XEN_NR_IPIS; ipi++) { @@ -1306,12 +1337,16 @@ static void restore_cpu_ipis(unsigned int cpu) evtchn = bind_ipi.port; /* Record the new mapping. */ + polled = info_for_irq(irq)->u.ipi.polled; evtchn_to_irq[evtchn] = irq; irq_info[irq] = mk_ipi_info(evtchn, ipi); bind_evtchn_to_cpu(evtchn, cpu); - /* Ready for use. */ - unmask_evtchn(evtchn); + /* Ready for use. Polled IPIs remain masked */ + if (polled) + info_for_irq(irq)->u.ipi.polled = 1; + else + unmask_evtchn(evtchn); } } diff --git a/include/xen/events.h b/include/xen/events.h index 7e17e2a..b2f09ad 100644 --- a/include/xen/events.h +++ b/include/xen/events.h @@ -24,6 +24,10 @@ int bind_ipi_to_irqhandler(enum ipi_vector ipi, unsigned long irqflags, const char *devname, void *dev_id); +int bind_polled_ipi_to_irq(enum ipi_vector ipi, + unsigned int cpu, + unsigned long irqflags, + const char *devname); int bind_interdomain_evtchn_to_irqhandler(unsigned int remote_domain, unsigned int remote_port, irq_handler_t handler, -- 1.5.6.5 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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