Release 4.10 arch/x86/xen/time.c

Directory: arch/x86/xen
/*
 * Xen time implementation.
 *
 * This is implemented in terms of a clocksource driver which uses
 * the hypervisor clock as a nanosecond timebase, and a clockevent
 * driver which uses the hypervisor's timer mechanism.
 *
 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
 */
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/pvclock_gtod.h>
#include <linux/timekeeper_internal.h>

#include <asm/pvclock.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>

#include <xen/events.h>
#include <xen/features.h>
#include <xen/interface/xen.h>
#include <xen/interface/vcpu.h>

#include "xen-ops.h"

/* Xen may fire a timer up to this many ns early */

#define TIMER_SLOP	100000

/* Get the TSC speed from Xen */


static unsigned long xen_tsc_khz(void)
{
	struct pvclock_vcpu_time_info *info =
		&HYPERVISOR_shared_info->vcpu_info[0].time;

	return pvclock_tsc_khz(info);
}

Contributors
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jeremy fitzhardinge jeremy fitzhardinge 25 83.33% 1 20.00%
glauber de oliveira costa glauber de oliveira costa 2 6.67% 1 20.00%
stefano stabellini stefano stabellini 1 3.33% 1 20.00%
alok kataria alok kataria 1 3.33% 1 20.00%
gerd hoffmann gerd hoffmann 1 3.33% 1 20.00%
Total 30 100.00% 5 100.00%



u64 xen_clocksource_read(void)
{
        struct pvclock_vcpu_time_info *src;
	u64 ret;

	preempt_disable_notrace();
	src = &__this_cpu_read(xen_vcpu)->time;
	ret = pvclock_clocksource_read(src);
	preempt_enable_notrace();
	return ret;
}

Contributors
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jeremy fitzhardinge jeremy fitzhardinge 30 73.17% 3 42.86%
gerd hoffmann gerd hoffmann 5 12.20% 1 14.29%
boris ostrovsky boris ostrovsky 3 7.32% 1 14.29%
thomas gleixner thomas gleixner 2 4.88% 1 14.29%
christoph lameter christoph lameter 1 2.44% 1 14.29%
Total 41 100.00% 7 100.00%



static u64 xen_clocksource_get_cycles(struct clocksource *cs)
{
	return xen_clocksource_read();
}

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magnus damm magnus damm 14 93.33% 1 50.00%
thomas gleixner thomas gleixner 1 6.67% 1 50.00%
Total 15 100.00% 2 100.00%



static void xen_read_wallclock(struct timespec *ts)
{
	struct shared_info *s = HYPERVISOR_shared_info;
	struct pvclock_wall_clock *wall_clock = &(s->wc);
        struct pvclock_vcpu_time_info *vcpu_time;

	vcpu_time = &get_cpu_var(xen_vcpu)->time;
	pvclock_read_wallclock(wall_clock, vcpu_time, ts);
	put_cpu_var(xen_vcpu);
}

Contributors
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jeremy fitzhardinge jeremy fitzhardinge 33 55.93% 1 50.00%
gerd hoffmann gerd hoffmann 26 44.07% 1 50.00%
Total 59 100.00% 2 100.00%



static void xen_get_wallclock(struct timespec *now)
{
	xen_read_wallclock(now);
}

Contributors
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jeremy fitzhardinge jeremy fitzhardinge 9 56.25% 1 33.33%
david vrabel david vrabel 6 37.50% 1 33.33%
stefano stabellini stefano stabellini 1 6.25% 1 33.33%
Total 16 100.00% 3 100.00%



static int xen_set_wallclock(const struct timespec *now)
{
	return -1;
}

Contributors
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jeremy fitzhardinge jeremy fitzhardinge 11 68.75% 1 33.33%
david vrabel david vrabel 4 25.00% 1 33.33%
stefano stabellini stefano stabellini 1 6.25% 1 33.33%
Total 16 100.00% 3 100.00%



static int xen_pvclock_gtod_notify(struct notifier_block *nb,
				   unsigned long was_set, void *priv)
{
	/* Protected by the calling core code serialization */
	static struct timespec64 next_sync;

	struct xen_platform_op op;
	struct timespec64 now;
	struct timekeeper *tk = priv;
	static bool settime64_supported = true;
	int ret;

	now.tv_sec = tk->xtime_sec;
	now.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);

	/*
         * We only take the expensive HV call when the clock was set
         * or when the 11 minutes RTC synchronization time elapsed.
         */
	if (!was_set && timespec64_compare(&now, &next_sync) < 0)
		return NOTIFY_OK;

again:
	if (settime64_supported) {
		op.cmd = XENPF_settime64;
		op.u.settime64.mbz = 0;
		op.u.settime64.secs = now.tv_sec;
		op.u.settime64.nsecs = now.tv_nsec;
		op.u.settime64.system_time = xen_clocksource_read();
	} else {
		op.cmd = XENPF_settime32;
		op.u.settime32.secs = now.tv_sec;
		op.u.settime32.nsecs = now.tv_nsec;
		op.u.settime32.system_time = xen_clocksource_read();
	}

	ret = HYPERVISOR_platform_op(&op);

	if (ret == -ENOSYS && settime64_supported) {
		settime64_supported = false;
		goto again;
	}
	if (ret < 0)
		return NOTIFY_BAD;

	/*
         * Move the next drift compensation time 11 minutes
         * ahead. That's emulating the sync_cmos_clock() update for
         * the hardware RTC.
         */
	next_sync = now;
	next_sync.tv_sec += 11 * 60;

	return NOTIFY_OK;
}

Contributors
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stefano stabellini stefano stabellini 141 55.95% 4 50.00%
jeremy fitzhardinge jeremy fitzhardinge 57 22.62% 2 25.00%
david vrabel david vrabel 54 21.43% 2 25.00%
Total 252 100.00% 8 100.00%


static struct notifier_block xen_pvclock_gtod_notifier = {
	.notifier_call = xen_pvclock_gtod_notify,
};


static struct clocksource xen_clocksource __read_mostly = {
	.name = "xen",
	.rating = 400,
	.read = xen_clocksource_get_cycles,
	.mask = ~0,
	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};

/*
   Xen clockevent implementation

   Xen has two clockevent implementations:

   The old timer_op one works with all released versions of Xen prior
   to version 3.0.4.  This version of the hypervisor provides a
   single-shot timer with nanosecond resolution.  However, sharing the
   same event channel is a 100Hz tick which is delivered while the
   vcpu is running.  We don't care about or use this tick, but it will
   cause the core time code to think the timer fired too soon, and
   will end up resetting it each time.  It could be filtered, but
   doing so has complications when the ktime clocksource is not yet
   the xen clocksource (ie, at boot time).

   The new vcpu_op-based timer interface allows the tick timer period
   to be changed or turned off.  The tick timer is not useful as a
   periodic timer because events are only delivered to running vcpus.
   The one-shot timer can report when a timeout is in the past, so
   set_next_event is capable of returning -ETIME when appropriate.
   This interface is used when available.
*/


/*
  Get a hypervisor absolute time.  In theory we could maintain an
  offset between the kernel's time and the hypervisor's time, and
  apply that to a kernel's absolute timeout.  Unfortunately the
  hypervisor and kernel times can drift even if the kernel is using
  the Xen clocksource, because ntp can warp the kernel's clocksource.
*/


static s64 get_abs_timeout(unsigned long delta)
{
	return xen_clocksource_read() + delta;
}

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jeremy fitzhardinge jeremy fitzhardinge 16 100.00% 1 100.00%
Total 16 100.00% 1 100.00%



static int xen_timerop_shutdown(struct clock_event_device *evt)
{
	/* cancel timeout */
	HYPERVISOR_set_timer_op(0);

	return 0;
}

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jeremy fitzhardinge jeremy fitzhardinge 14 70.00% 1 50.00%
viresh kumar viresh kumar 6 30.00% 1 50.00%
Total 20 100.00% 2 100.00%



static int xen_timerop_set_next_event(unsigned long delta,
				      struct clock_event_device *evt)
{
	WARN_ON(!clockevent_state_oneshot(evt));

	if (HYPERVISOR_set_timer_op(get_abs_timeout(delta)) < 0)
		BUG();

	/* We may have missed the deadline, but there's no real way of
           knowing for sure.  If the event was in the past, then we'll
           get an immediate interrupt. */

	return 0;
}

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jeremy fitzhardinge jeremy fitzhardinge 39 90.70% 1 50.00%
viresh kumar viresh kumar 4 9.30% 1 50.00%
Total 43 100.00% 2 100.00%


static const struct clock_event_device xen_timerop_clockevent = {
	.name			= "xen",
	.features		= CLOCK_EVT_FEAT_ONESHOT,

	.max_delta_ns		= 0xffffffff,
	.min_delta_ns		= TIMER_SLOP,

	.mult			= 1,
	.shift			= 0,
	.rating			= 500,

	.set_state_shutdown	= xen_timerop_shutdown,
	.set_next_event		= xen_timerop_set_next_event,
};



static int xen_vcpuop_shutdown(struct clock_event_device *evt)
{
	int cpu = smp_processor_id();

	if (HYPERVISOR_vcpu_op(VCPUOP_stop_singleshot_timer, xen_vcpu_nr(cpu),
			       NULL) ||
	    HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, xen_vcpu_nr(cpu),
			       NULL))
		BUG();

	return 0;
}

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jeremy fitzhardinge jeremy fitzhardinge 29 59.18% 1 33.33%
viresh kumar viresh kumar 14 28.57% 1 33.33%
vitaly kuznetsov vitaly kuznetsov 6 12.24% 1 33.33%
Total 49 100.00% 3 100.00%



static int xen_vcpuop_set_oneshot(struct clock_event_device *evt)
{
	int cpu = smp_processor_id();

	if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, xen_vcpu_nr(cpu),
			       NULL))
		BUG();

	return 0;
}

Contributors
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viresh kumar viresh kumar 19 51.35% 1 33.33%
jeremy fitzhardinge jeremy fitzhardinge 15 40.54% 1 33.33%
vitaly kuznetsov vitaly kuznetsov 3 8.11% 1 33.33%
Total 37 100.00% 3 100.00%



static int xen_vcpuop_set_next_event(unsigned long delta,
				     struct clock_event_device *evt)
{
	int cpu = smp_processor_id();
	struct vcpu_set_singleshot_timer single;
	int ret;

	WARN_ON(!clockevent_state_oneshot(evt));

	single.timeout_abs_ns = get_abs_timeout(delta);
	/* Get an event anyway, even if the timeout is already expired */
	single.flags = 0;

	ret = HYPERVISOR_vcpu_op(VCPUOP_set_singleshot_timer, xen_vcpu_nr(cpu),
				 &single);
	BUG_ON(ret != 0);

	return ret;
}

Contributors
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jeremy fitzhardinge jeremy fitzhardinge 69 88.46% 1 25.00%
viresh kumar viresh kumar 4 5.13% 1 25.00%
vitaly kuznetsov vitaly kuznetsov 3 3.85% 1 25.00%
stefano stabellini stefano stabellini 2 2.56% 1 25.00%
Total 78 100.00% 4 100.00%


static const struct clock_event_device xen_vcpuop_clockevent = {
	.name = "xen",
	.features = CLOCK_EVT_FEAT_ONESHOT,

	.max_delta_ns = 0xffffffff,
	.min_delta_ns = TIMER_SLOP,

	.mult = 1,
	.shift = 0,
	.rating = 500,

	.set_state_shutdown = xen_vcpuop_shutdown,
	.set_state_oneshot = xen_vcpuop_set_oneshot,
	.set_next_event = xen_vcpuop_set_next_event,
};


static const struct clock_event_device *xen_clockevent =
	&xen_timerop_clockevent;


struct xen_clock_event_device {
	
struct clock_event_device evt;
	
char name[16];
};
static DEFINE_PER_CPU(struct xen_clock_event_device, xen_clock_events) = { .evt.irq = -1 };



static irqreturn_t xen_timer_interrupt(int irq, void *dev_id)
{
	struct clock_event_device *evt = this_cpu_ptr(&xen_clock_events.evt);
	irqreturn_t ret;

	ret = IRQ_NONE;
	if (evt->event_handler) {
		evt->event_handler(evt);
		ret = IRQ_HANDLED;
	}

	return ret;
}

Contributors
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jeremy fitzhardinge jeremy fitzhardinge 50 90.91% 1 33.33%
christoph lameter christoph lameter 3 5.45% 1 33.33%
konrad rzeszutek wilk konrad rzeszutek wilk 2 3.64% 1 33.33%
Total 55 100.00% 3 100.00%



void xen_teardown_timer(int cpu)
{
	struct clock_event_device *evt;
	BUG_ON(cpu == 0);
	evt = &per_cpu(xen_clock_events, cpu).evt;

	if (evt->irq >= 0) {
		unbind_from_irqhandler(evt->irq, NULL);
		evt->irq = -1;
	}
}

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konrad rzeszutek wilk konrad rzeszutek wilk 58 100.00% 1 100.00%
Total 58 100.00% 1 100.00%



void xen_setup_timer(int cpu)
{
	struct xen_clock_event_device *xevt = &per_cpu(xen_clock_events, cpu);
	struct clock_event_device *evt = &xevt->evt;
	int irq;

	WARN(evt->irq >= 0, "IRQ%d for CPU%d is already allocated\n", evt->irq, cpu);
	if (evt->irq >= 0)
		xen_teardown_timer(cpu);

	printk(KERN_INFO "installing Xen timer for CPU %d\n", cpu);

	snprintf(xevt->name, sizeof(xevt->name), "timer%d", cpu);

	irq = bind_virq_to_irqhandler(VIRQ_TIMER, cpu, xen_timer_interrupt,
				      IRQF_PERCPU|IRQF_NOBALANCING|IRQF_TIMER|
				      IRQF_FORCE_RESUME|IRQF_EARLY_RESUME,
				      xevt->name, NULL);
	(void)xen_set_irq_priority(irq, XEN_IRQ_PRIORITY_MAX);

	memcpy(evt, xen_clockevent, sizeof(*evt));

	evt->cpumask = cpumask_of(cpu);
	evt->irq = irq;
}


Contributors
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jeremy fitzhardinge jeremy fitzhardinge 72 46.45% 2 18.18%
konrad rzeszutek wilk konrad rzeszutek wilk 38 24.52% 3 27.27%
vitaly kuznetsov vitaly kuznetsov 28 18.06% 1 9.09%
david vrabel david vrabel 12 7.74% 2 18.18%
ian campbell ian campbell 4 2.58% 2 18.18%
rusty russell rusty russell 1 0.65% 1 9.09%
Total 155 100.00% 11 100.00%



void xen_setup_cpu_clockevents(void)
{
	clockevents_register_device(this_cpu_ptr(&xen_clock_events.evt));
}

Contributors
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jeremy fitzhardinge jeremy fitzhardinge 13 72.22% 2 50.00%
christoph lameter christoph lameter 3 16.67% 1 25.00%
konrad rzeszutek wilk konrad rzeszutek wilk 2 11.11% 1 25.00%
Total 18 100.00% 4 100.00%



void xen_timer_resume(void)
{
	int cpu;

	pvclock_resume();

	if (xen_clockevent != &xen_vcpuop_clockevent)
		return;

	for_each_online_cpu(cpu) {
		if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer,
				       xen_vcpu_nr(cpu), NULL))
			BUG();
	}
}

Contributors
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jeremy fitzhardinge jeremy fitzhardinge 41 93.18% 2 66.67%
vitaly kuznetsov vitaly kuznetsov 3 6.82% 1 33.33%
Total 44 100.00% 3 100.00%


static const struct pv_time_ops xen_time_ops __initconst = {
	.sched_clock = xen_clocksource_read,
	.steal_clock = xen_steal_clock,
};



static void __init xen_time_init(void)
{
	int cpu = smp_processor_id();
	struct timespec tp;

	/* As Dom0 is never moved, no penalty on using TSC there */
	if (xen_initial_domain())
		xen_clocksource.rating = 275;

	clocksource_register_hz(&xen_clocksource, NSEC_PER_SEC);

	if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, xen_vcpu_nr(cpu),
			       NULL) == 0) {
		/* Successfully turned off 100Hz tick, so we have the
                   vcpuop-based timer interface */
		printk(KERN_DEBUG "Xen: using vcpuop timer interface\n");
		xen_clockevent = &xen_vcpuop_clockevent;
	}

	/* Set initial system time with full resolution */
	xen_read_wallclock(&tp);
	do_settimeofday(&tp);

	setup_force_cpu_cap(X86_FEATURE_TSC);

	xen_setup_runstate_info(cpu);
	xen_setup_timer(cpu);
	xen_setup_cpu_clockevents();

	xen_time_setup_guest();

	if (xen_initial_domain())
		pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier);
}

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jeremy fitzhardinge jeremy fitzhardinge 64 56.14% 3 23.08%
imre palik imre palik 12 10.53% 1 7.69%
david vrabel david vrabel 11 9.65% 1 7.69%
john stultz john stultz 10 8.77% 2 15.38%
ian campbell ian campbell 5 4.39% 1 7.69%
andi kleen andi kleen 4 3.51% 1 7.69%
vitaly kuznetsov vitaly kuznetsov 3 2.63% 1 7.69%
juergen gross juergen gross 3 2.63% 1 7.69%
stefano stabellini stefano stabellini 1 0.88% 1 7.69%
daniel kiper daniel kiper 1 0.88% 1 7.69%
Total 114 100.00% 13 100.00%



void __init xen_init_time_ops(void)
{
	pv_time_ops = xen_time_ops;

	x86_init.timers.timer_init = xen_time_init;
	x86_init.timers.setup_percpu_clockev = x86_init_noop;
	x86_cpuinit.setup_percpu_clockev = x86_init_noop;

	x86_platform.calibrate_tsc = xen_tsc_khz;
	x86_platform.get_wallclock = xen_get_wallclock;
	/* Dom0 uses the native method to set the hardware RTC. */
	if (!xen_initial_domain())
		x86_platform.set_wallclock = xen_set_wallclock;
}

Contributors
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stefano stabellini stefano stabellini 51 86.44% 1 33.33%
david vrabel david vrabel 7 11.86% 1 33.33%
daniel kiper daniel kiper 1 1.69% 1 33.33%
Total 59 100.00% 3 100.00%

#ifdef CONFIG_XEN_PVHVM


static void xen_hvm_setup_cpu_clockevents(void)
{
	int cpu = smp_processor_id();
	xen_setup_runstate_info(cpu);
	/*
         * xen_setup_timer(cpu) - snprintf is bad in atomic context. Hence
         * doing it xen_hvm_cpu_notify (which gets called by smp_init during
         * early bootup and also during CPU hotplug events).
         */
	xen_setup_cpu_clockevents();
}

Contributors
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stefano stabellini stefano stabellini 22 95.65% 1 50.00%
konrad rzeszutek wilk konrad rzeszutek wilk 1 4.35% 1 50.00%
Total 23 100.00% 2 100.00%



void __init xen_hvm_init_time_ops(void)
{
	if (!xen_feature(XENFEAT_hvm_safe_pvclock)) {
		printk(KERN_INFO "Xen doesn't support pvclock on HVM,"
				"disable pv timer\n");
		return;
	}

	pv_time_ops = xen_time_ops;
	x86_init.timers.setup_percpu_clockev = xen_time_init;
	x86_cpuinit.setup_percpu_clockev = xen_hvm_setup_cpu_clockevents;

	x86_platform.calibrate_tsc = xen_tsc_khz;
	x86_platform.get_wallclock = xen_get_wallclock;
	x86_platform.set_wallclock = xen_set_wallclock;
}
Contributors
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stefano stabellini stefano stabellini 61 98.39% 1 50.00%
daniel kiper daniel kiper 1 1.61% 1 50.00%
Total 62 100.00% 2 100.00%

#endif
Overall Contributors
Person Tokens Prop Commits CommitProp
jeremy fitzhardinge jeremy fitzhardinge 779 50.52% 8 17.02%
stefano stabellini stefano stabellini 304 19.71% 7 14.89%
konrad rzeszutek wilk konrad rzeszutek wilk 127 8.24% 5 10.64%
david vrabel david vrabel 109 7.07% 5 10.64%
viresh kumar viresh kumar 56 3.63% 1 2.13%
vitaly kuznetsov vitaly kuznetsov 49 3.18% 2 4.26%
gerd hoffmann gerd hoffmann 35 2.27% 1 2.13%
magnus damm magnus damm 15 0.97% 1 2.13%
imre palik imre palik 12 0.78% 1 2.13%
john stultz john stultz 10 0.65% 2 4.26%
ian campbell ian campbell 9 0.58% 3 6.38%
juergen gross juergen gross 8 0.52% 2 4.26%
christoph lameter christoph lameter 7 0.45% 1 2.13%
andi kleen andi kleen 4 0.26% 1 2.13%
daniel kiper daniel kiper 4 0.26% 1 2.13%
thomas gleixner thomas gleixner 3 0.19% 1 2.13%
tejun heo tejun heo 3 0.19% 1 2.13%
boris ostrovsky boris ostrovsky 3 0.19% 1 2.13%
alok kataria alok kataria 2 0.13% 1 2.13%
glauber de oliveira costa glauber de oliveira costa 2 0.13% 1 2.13%
rusty russell rusty russell 1 0.06% 1 2.13%
Total 1542 100.00% 47 100.00%
Directory: arch/x86/xen

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	Person	Tokens	Prop	Commits	CommitProp
jeremy fitzhardinge	jeremy fitzhardinge	25	83.33%	1	20.00%
glauber de oliveira costa	glauber de oliveira costa	2	6.67%	1	20.00%
stefano stabellini	stefano stabellini	1	3.33%	1	20.00%
alok kataria	alok kataria	1	3.33%	1	20.00%
gerd hoffmann	gerd hoffmann	1	3.33%	1	20.00%
	Total	30	100.00%	5	100.00%
cregit-Linux how code gets into the kernel

Release 4.10 arch/x86/xen/time.c

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