[mirror_ubuntu-artful-kernel.git] / arch / x86 / xen / time.c

/*
 * 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);
}

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;
}

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

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);
}

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

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

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;
}

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;
}

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

	return 0;
}

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;
}

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

	.max_delta_ns		= 0xffffffff,
	.max_delta_ticks	= 0xffffffff,
	.min_delta_ns		= TIMER_SLOP,
	.min_delta_ticks	= 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;
}

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;
}

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;
}

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

	.max_delta_ns = 0xffffffff,
	.max_delta_ticks = 0xffffffff,
	.min_delta_ns = TIMER_SLOP,
	.min_delta_ticks = 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;
}

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

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

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;
}


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

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();
	}
}

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);
}

void __ref 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;
}

#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();
}

void __init xen_hvm_init_time_ops(void)
{
	/*
	 * vector callback is needed otherwise we cannot receive interrupts
	 * on cpu > 0 and at this point we don't know how many cpus are
	 * available.
	 */
	if (!xen_have_vector_callback)
		return;

	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;
}
#endif
Commit	Line	Data
15c84731 JF	1	/*
	2	* Xen time implementation.
	3	*
	4	* This is implemented in terms of a clocksource driver which uses
	5	* the hypervisor clock as a nanosecond timebase, and a clockevent
	6	* driver which uses the hypervisor's timer mechanism.
	7	*
	8	* Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
	9	*/
	10	#include <linux/kernel.h>
	11	#include <linux/interrupt.h>
	12	#include <linux/clocksource.h>
	13	#include <linux/clockchips.h>
5a0e3ad6	14	#include <linux/gfp.h>
c9d76a24	15	#include <linux/slab.h>
5584880e	16	#include <linux/pvclock_gtod.h>
76096863	17	#include <linux/timekeeper_internal.h>
15c84731	18
1c7b67f7	19	#include <asm/pvclock.h>
15c84731 JF	20	#include <asm/xen/hypervisor.h>
	21	#include <asm/xen/hypercall.h>
	22
	23	#include <xen/events.h>
409771d2	24	#include <xen/features.h>
15c84731 JF	25	#include <xen/interface/xen.h>
	26	#include <xen/interface/vcpu.h>
	27
	28	#include "xen-ops.h"
	29
15c84731 JF	30	/* Xen may fire a timer up to this many ns early */
15c84731 JF	31	#define TIMER_SLOP 100000
f91a8b44	32
e93ef949	33	/* Get the TSC speed from Xen */
409771d2	34	static unsigned long xen_tsc_khz(void)
15c84731	35	{
3807f345	36	struct pvclock_vcpu_time_info *info =
15c84731 JF	37	&HYPERVISOR_shared_info->vcpu_info[0].time;
15c84731 JF	38
3807f345	39	return pvclock_tsc_khz(info);
15c84731 JF	40	}
15c84731 JF	41
a5a1d1c2	42	u64 xen_clocksource_read(void)
15c84731	43	{
1c7b67f7	44	struct pvclock_vcpu_time_info *src;
a5a1d1c2	45	u64 ret;
15c84731	46
f1c39625	47	preempt_disable_notrace();
3251f20b	48	src = &__this_cpu_read(xen_vcpu)->time;
1c7b67f7	49	ret = pvclock_clocksource_read(src);
f1c39625	50	preempt_enable_notrace();
15c84731 JF	51	return ret;
	52	}
	53
a5a1d1c2	54	static u64 xen_clocksource_get_cycles(struct clocksource *cs)
8e19608e MD	55	{
	56	return xen_clocksource_read();
	57	}
	58
15c84731 JF	59	static void xen_read_wallclock(struct timespec *ts)
15c84731 JF	60	{
1c7b67f7 GH	61	struct shared_info *s = HYPERVISOR_shared_info;
	62	struct pvclock_wall_clock *wall_clock = &(s->wc);
	63	struct pvclock_vcpu_time_info *vcpu_time;
15c84731	64
1c7b67f7 GH	65	vcpu_time = &get_cpu_var(xen_vcpu)->time;
	66	pvclock_read_wallclock(wall_clock, vcpu_time, ts);
	67	put_cpu_var(xen_vcpu);
15c84731 JF	68	}
15c84731 JF	69
3565184e	70	static void xen_get_wallclock(struct timespec *now)
15c84731	71	{
3565184e	72	xen_read_wallclock(now);
15c84731	73	}
15c84731	74
3565184e	75	static int xen_set_wallclock(const struct timespec *now)
15c84731	76	{
47433b8c	77	return -1;
15c84731 JF	78	}
15c84731 JF	79
47433b8c DV	80	static int xen_pvclock_gtod_notify(struct notifier_block *nb,
47433b8c DV	81	unsigned long was_set, void *priv)
15c84731	82	{
47433b8c	83	/* Protected by the calling core code serialization */
187b26a9	84	static struct timespec64 next_sync;
5584880e	85
fdb9eb9f	86	struct xen_platform_op op;
76096863 SS	87	struct timespec64 now;
	88	struct timekeeper *tk = priv;
	89	static bool settime64_supported = true;
	90	int ret;
fdb9eb9f	91
76096863 SS	92	now.tv_sec = tk->xtime_sec;
76096863 SS	93	now.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
5584880e	94
47433b8c DV	95	/*
	96	* We only take the expensive HV call when the clock was set
	97	* or when the 11 minutes RTC synchronization time elapsed.
	98	*/
187b26a9	99	if (!was_set && timespec64_compare(&now, &next_sync) < 0)
47433b8c	100	return NOTIFY_OK;
fdb9eb9f	101
76096863 SS	102	again:
	103	if (settime64_supported) {
	104	op.cmd = XENPF_settime64;
	105	op.u.settime64.mbz = 0;
	106	op.u.settime64.secs = now.tv_sec;
	107	op.u.settime64.nsecs = now.tv_nsec;
	108	op.u.settime64.system_time = xen_clocksource_read();
	109	} else {
	110	op.cmd = XENPF_settime32;
	111	op.u.settime32.secs = now.tv_sec;
	112	op.u.settime32.nsecs = now.tv_nsec;
	113	op.u.settime32.system_time = xen_clocksource_read();
	114	}
	115
	116	ret = HYPERVISOR_platform_op(&op);
	117
	118	if (ret == -ENOSYS && settime64_supported) {
	119	settime64_supported = false;
	120	goto again;
	121	}
	122	if (ret < 0)
	123	return NOTIFY_BAD;
fdb9eb9f	124
47433b8c DV	125	/*
	126	* Move the next drift compensation time 11 minutes
	127	* ahead. That's emulating the sync_cmos_clock() update for
	128	* the hardware RTC.
	129	*/
	130	next_sync = now;
	131	next_sync.tv_sec += 11 * 60;
	132
5584880e	133	return NOTIFY_OK;
15c84731 JF	134	}
15c84731 JF	135
5584880e DV	136	static struct notifier_block xen_pvclock_gtod_notifier = {
	137	.notifier_call = xen_pvclock_gtod_notify,
	138	};
	139
15c84731 JF	140	static struct clocksource xen_clocksource __read_mostly = {
	141	.name = "xen",
	142	.rating = 400,
8e19608e	143	.read = xen_clocksource_get_cycles,
15c84731	144	.mask = ~0,
15c84731 JF	145	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
	146	};
	147
	148	/*
	149	Xen clockevent implementation
	150
	151	Xen has two clockevent implementations:
	152
	153	The old timer_op one works with all released versions of Xen prior
	154	to version 3.0.4. This version of the hypervisor provides a
	155	single-shot timer with nanosecond resolution. However, sharing the
	156	same event channel is a 100Hz tick which is delivered while the
	157	vcpu is running. We don't care about or use this tick, but it will
	158	cause the core time code to think the timer fired too soon, and
	159	will end up resetting it each time. It could be filtered, but
	160	doing so has complications when the ktime clocksource is not yet
	161	the xen clocksource (ie, at boot time).
	162
	163	The new vcpu_op-based timer interface allows the tick timer period
	164	to be changed or turned off. The tick timer is not useful as a
	165	periodic timer because events are only delivered to running vcpus.
	166	The one-shot timer can report when a timeout is in the past, so
	167	set_next_event is capable of returning -ETIME when appropriate.
	168	This interface is used when available.
	169	*/
	170
	171
	172	/*
	173	Get a hypervisor absolute time. In theory we could maintain an
	174	offset between the kernel's time and the hypervisor's time, and
	175	apply that to a kernel's absolute timeout. Unfortunately the
	176	hypervisor and kernel times can drift even if the kernel is using
	177	the Xen clocksource, because ntp can warp the kernel's clocksource.
	178	*/
	179	static s64 get_abs_timeout(unsigned long delta)
	180	{
	181	return xen_clocksource_read() + delta;
	182	}
	183
955381dd	184	static int xen_timerop_shutdown(struct clock_event_device *evt)
15c84731	185	{
955381dd VK	186	/* cancel timeout */
	187	HYPERVISOR_set_timer_op(0);
	188
	189	return 0;
15c84731 JF	190	}
	191
	192	static int xen_timerop_set_next_event(unsigned long delta,
	193	struct clock_event_device *evt)
	194	{
955381dd	195	WARN_ON(!clockevent_state_oneshot(evt));
15c84731 JF	196
	197	if (HYPERVISOR_set_timer_op(get_abs_timeout(delta)) < 0)
	198	BUG();
	199
	200	/* We may have missed the deadline, but there's no real way of
	201	knowing for sure. If the event was in the past, then we'll
	202	get an immediate interrupt. */
	203
	204	return 0;
	205	}
	206
	207	static const struct clock_event_device xen_timerop_clockevent = {
955381dd VK	208	.name = "xen",
955381dd VK	209	.features = CLOCK_EVT_FEAT_ONESHOT,
15c84731	210
955381dd	211	.max_delta_ns = 0xffffffff,
3d18d661	212	.max_delta_ticks = 0xffffffff,
955381dd	213	.min_delta_ns = TIMER_SLOP,
3d18d661	214	.min_delta_ticks = TIMER_SLOP,
15c84731	215
955381dd VK	216	.mult = 1,
	217	.shift = 0,
	218	.rating = 500,
15c84731	219
955381dd VK	220	.set_state_shutdown = xen_timerop_shutdown,
955381dd VK	221	.set_next_event = xen_timerop_set_next_event,
15c84731 JF	222	};
15c84731 JF	223
955381dd VK	224	static int xen_vcpuop_shutdown(struct clock_event_device *evt)
	225	{
	226	int cpu = smp_processor_id();
15c84731	227
ad5475f9 VK	228	if (HYPERVISOR_vcpu_op(VCPUOP_stop_singleshot_timer, xen_vcpu_nr(cpu),
	229	NULL) \|\|
	230	HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, xen_vcpu_nr(cpu),
	231	NULL))
955381dd	232	BUG();
15c84731	233
955381dd VK	234	return 0;
	235	}
	236
	237	static int xen_vcpuop_set_oneshot(struct clock_event_device *evt)
15c84731 JF	238	{
	239	int cpu = smp_processor_id();
	240
ad5475f9 VK	241	if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, xen_vcpu_nr(cpu),
ad5475f9 VK	242	NULL))
955381dd VK	243	BUG();
	244
	245	return 0;
15c84731 JF	246	}
	247
	248	static int xen_vcpuop_set_next_event(unsigned long delta,
	249	struct clock_event_device *evt)
	250	{
	251	int cpu = smp_processor_id();
	252	struct vcpu_set_singleshot_timer single;
	253	int ret;
	254
955381dd	255	WARN_ON(!clockevent_state_oneshot(evt));
15c84731 JF	256
15c84731 JF	257	single.timeout_abs_ns = get_abs_timeout(delta);
c06b6d70 SS	258	/* Get an event anyway, even if the timeout is already expired */
c06b6d70 SS	259	single.flags = 0;
15c84731	260
ad5475f9 VK	261	ret = HYPERVISOR_vcpu_op(VCPUOP_set_singleshot_timer, xen_vcpu_nr(cpu),
ad5475f9 VK	262	&single);
c06b6d70	263	BUG_ON(ret != 0);
15c84731 JF	264
	265	return ret;
	266	}
	267
	268	static const struct clock_event_device xen_vcpuop_clockevent = {
	269	.name = "xen",
	270	.features = CLOCK_EVT_FEAT_ONESHOT,
	271
	272	.max_delta_ns = 0xffffffff,
3d18d661	273	.max_delta_ticks = 0xffffffff,
15c84731	274	.min_delta_ns = TIMER_SLOP,
3d18d661	275	.min_delta_ticks = TIMER_SLOP,
15c84731 JF	276
	277	.mult = 1,
	278	.shift = 0,
	279	.rating = 500,
	280
955381dd VK	281	.set_state_shutdown = xen_vcpuop_shutdown,
955381dd VK	282	.set_state_oneshot = xen_vcpuop_set_oneshot,
15c84731 JF	283	.set_next_event = xen_vcpuop_set_next_event,
	284	};
	285
	286	static const struct clock_event_device *xen_clockevent =
	287	&xen_timerop_clockevent;
31620a19 KRW	288
	289	struct xen_clock_event_device {
	290	struct clock_event_device evt;
7be0772d	291	char name[16];
31620a19 KRW	292	};
31620a19 KRW	293	static DEFINE_PER_CPU(struct xen_clock_event_device, xen_clock_events) = { .evt.irq = -1 };
15c84731 JF	294
	295	static irqreturn_t xen_timer_interrupt(int irq, void *dev_id)
	296	{
89cbc767	297	struct clock_event_device *evt = this_cpu_ptr(&xen_clock_events.evt);
15c84731 JF	298	irqreturn_t ret;
	299
	300	ret = IRQ_NONE;
	301	if (evt->event_handler) {
	302	evt->event_handler(evt);
	303	ret = IRQ_HANDLED;
	304	}
	305
	306	return ret;
	307	}
	308
09e99da7 KRW	309	void xen_teardown_timer(int cpu)
	310	{
	311	struct clock_event_device *evt;
09e99da7 KRW	312	evt = &per_cpu(xen_clock_events, cpu).evt;
	313
	314	if (evt->irq >= 0) {
	315	unbind_from_irqhandler(evt->irq, NULL);
	316	evt->irq = -1;
09e99da7 KRW	317	}
	318	}
	319
f87e4cac	320	void xen_setup_timer(int cpu)
15c84731	321	{
7be0772d VK	322	struct xen_clock_event_device *xevt = &per_cpu(xen_clock_events, cpu);
7be0772d VK	323	struct clock_event_device *evt = &xevt->evt;
15c84731 JF	324	int irq;
15c84731 JF	325
ef35a4e6	326	WARN(evt->irq >= 0, "IRQ%d for CPU%d is already allocated\n", evt->irq, cpu);
09e99da7 KRW	327	if (evt->irq >= 0)
09e99da7 KRW	328	xen_teardown_timer(cpu);
ef35a4e6	329
15c84731 JF	330	printk(KERN_INFO "installing Xen timer for CPU %d\n", cpu);
15c84731 JF	331
7be0772d	332	snprintf(xevt->name, sizeof(xevt->name), "timer%d", cpu);
15c84731 JF	333
15c84731 JF	334	irq = bind_virq_to_irqhandler(VIRQ_TIMER, cpu, xen_timer_interrupt,
9d71cee6	335	IRQF_PERCPU\|IRQF_NOBALANCING\|IRQF_TIMER\|
8d5999df	336	IRQF_FORCE_RESUME\|IRQF_EARLY_RESUME,
7be0772d	337	xevt->name, NULL);
8785c676	338	(void)xen_set_irq_priority(irq, XEN_IRQ_PRIORITY_MAX);
15c84731	339
15c84731 JF	340	memcpy(evt, xen_clockevent, sizeof(*evt));
15c84731 JF	341
320ab2b0	342	evt->cpumask = cpumask_of(cpu);
15c84731	343	evt->irq = irq;
f87e4cac JF	344	}
f87e4cac JF	345
d68d82af	346
f87e4cac JF	347	void xen_setup_cpu_clockevents(void)
f87e4cac JF	348	{
89cbc767	349	clockevents_register_device(this_cpu_ptr(&xen_clock_events.evt));
15c84731 JF	350	}
15c84731 JF	351
d07af1f0 JF	352	void xen_timer_resume(void)
	353	{
	354	int cpu;
	355
e7a3481c JF	356	pvclock_resume();
e7a3481c JF	357
d07af1f0 JF	358	if (xen_clockevent != &xen_vcpuop_clockevent)
	359	return;
	360
	361	for_each_online_cpu(cpu) {
ad5475f9 VK	362	if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer,
ad5475f9 VK	363	xen_vcpu_nr(cpu), NULL))
d07af1f0 JF	364	BUG();
	365	}
	366	}
	367
fb6ce5de	368	static const struct pv_time_ops xen_time_ops __initconst = {
ca50a5f3	369	.sched_clock = xen_clocksource_read,
d34c30cc	370	.steal_clock = xen_steal_clock,
409771d2 SS	371	};
409771d2 SS	372
fb6ce5de	373	static void __init xen_time_init(void)
15c84731 JF	374	{
15c84731 JF	375	int cpu = smp_processor_id();
c4507257	376	struct timespec tp;
15c84731	377
94dd85f6 PI	378	/* As Dom0 is never moved, no penalty on using TSC there */
	379	if (xen_initial_domain())
	380	xen_clocksource.rating = 275;
	381
b01cc1b0	382	clocksource_register_hz(&xen_clocksource, NSEC_PER_SEC);
15c84731	383
ad5475f9 VK	384	if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, xen_vcpu_nr(cpu),
ad5475f9 VK	385	NULL) == 0) {
f91a8b44	386	/* Successfully turned off 100Hz tick, so we have the
15c84731 JF	387	vcpuop-based timer interface */
	388	printk(KERN_DEBUG "Xen: using vcpuop timer interface\n");
	389	xen_clockevent = &xen_vcpuop_clockevent;
	390	}
	391
	392	/* Set initial system time with full resolution */
c4507257 JS	393	xen_read_wallclock(&tp);
c4507257 JS	394	do_settimeofday(&tp);
15c84731	395
404ee5b1	396	setup_force_cpu_cap(X86_FEATURE_TSC);
15c84731	397
be012920	398	xen_setup_runstate_info(cpu);
15c84731	399	xen_setup_timer(cpu);
f87e4cac	400	xen_setup_cpu_clockevents();
5584880e	401
ecb23dc6 JG	402	xen_time_setup_guest();
ecb23dc6 JG	403
5584880e DV	404	if (xen_initial_domain())
5584880e DV	405	pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier);
15c84731	406	}
409771d2	407
d162809f	408	void __ref xen_init_time_ops(void)
409771d2 SS	409	{
	410	pv_time_ops = xen_time_ops;
	411
	412	x86_init.timers.timer_init = xen_time_init;
	413	x86_init.timers.setup_percpu_clockev = x86_init_noop;
	414	x86_cpuinit.setup_percpu_clockev = x86_init_noop;
	415
	416	x86_platform.calibrate_tsc = xen_tsc_khz;
	417	x86_platform.get_wallclock = xen_get_wallclock;
47433b8c DV	418	/* Dom0 uses the native method to set the hardware RTC. */
	419	if (!xen_initial_domain())
	420	x86_platform.set_wallclock = xen_set_wallclock;
409771d2 SS	421	}
409771d2 SS	422
ca65f9fc	423	#ifdef CONFIG_XEN_PVHVM
409771d2 SS	424	static void xen_hvm_setup_cpu_clockevents(void)
	425	{
	426	int cpu = smp_processor_id();
	427	xen_setup_runstate_info(cpu);
7918c92a KRW	428	/*
	429	* xen_setup_timer(cpu) - snprintf is bad in atomic context. Hence
	430	* doing it xen_hvm_cpu_notify (which gets called by smp_init during
	431	* early bootup and also during CPU hotplug events).
	432	*/
409771d2 SS	433	xen_setup_cpu_clockevents();
	434	}
	435
fb6ce5de	436	void __init xen_hvm_init_time_ops(void)
409771d2	437	{
84d582d2 BO	438	/*
	439	* vector callback is needed otherwise we cannot receive interrupts
	440	* on cpu > 0 and at this point we don't know how many cpus are
	441	* available.
	442	*/
	443	if (!xen_have_vector_callback)
	444	return;
	445
409771d2 SS	446	if (!xen_feature(XENFEAT_hvm_safe_pvclock)) {
	447	printk(KERN_INFO "Xen doesn't support pvclock on HVM,"
	448	"disable pv timer\n");
	449	return;
	450	}
	451
	452	pv_time_ops = xen_time_ops;
	453	x86_init.timers.setup_percpu_clockev = xen_time_init;
	454	x86_cpuinit.setup_percpu_clockev = xen_hvm_setup_cpu_clockevents;
	455
	456	x86_platform.calibrate_tsc = xen_tsc_khz;
	457	x86_platform.get_wallclock = xen_get_wallclock;
	458	x86_platform.set_wallclock = xen_set_wallclock;
	459	}
ca65f9fc	460	#endif