[linux-block.git] / arch / x86 / kernel / kvmclock.c

/*  KVM paravirtual clock driver. A clocksource implementation
    Copyright (C) 2008 Glauber de Oliveira Costa, Red Hat Inc.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#include <linux/clocksource.h>
#include <linux/kvm_para.h>
#include <asm/pvclock.h>
#include <asm/msr.h>
#include <asm/apic.h>
#include <linux/percpu.h>
#include <linux/hardirq.h>
#include <linux/sched.h>
#include <linux/sched/clock.h>
#include <linux/mm.h>

#include <asm/mem_encrypt.h>
#include <asm/x86_init.h>
#include <asm/reboot.h>
#include <asm/kvmclock.h>

static int kvmclock __ro_after_init = 1;
static int msr_kvm_system_time = MSR_KVM_SYSTEM_TIME;
static int msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK;
static u64 kvm_sched_clock_offset;

static int parse_no_kvmclock(char *arg)
{
	kvmclock = 0;
	return 0;
}
early_param("no-kvmclock", parse_no_kvmclock);

/* Aligned to page sizes to match whats mapped via vsyscalls to userspace */
#define HV_CLOCK_SIZE	(sizeof(struct pvclock_vsyscall_time_info) * NR_CPUS)

static u8 hv_clock_mem[PAGE_ALIGN(HV_CLOCK_SIZE)] __aligned(PAGE_SIZE);

/* The hypervisor will put information about time periodically here */
static struct pvclock_vsyscall_time_info *hv_clock;
static struct pvclock_wall_clock wall_clock;

/*
 * The wallclock is the time of day when we booted. Since then, some time may
 * have elapsed since the hypervisor wrote the data. So we try to account for
 * that with system time
 */
static void kvm_get_wallclock(struct timespec64 *now)
{
	struct pvclock_vcpu_time_info *vcpu_time;
	int low, high;
	int cpu;

	low = (int)slow_virt_to_phys(&wall_clock);
	high = ((u64)slow_virt_to_phys(&wall_clock) >> 32);

	native_write_msr(msr_kvm_wall_clock, low, high);

	cpu = get_cpu();

	vcpu_time = &hv_clock[cpu].pvti;
	pvclock_read_wallclock(&wall_clock, vcpu_time, now);

	put_cpu();
}

static int kvm_set_wallclock(const struct timespec64 *now)
{
	return -ENODEV;
}

static u64 kvm_clock_read(void)
{
	struct pvclock_vcpu_time_info *src;
	u64 ret;
	int cpu;

	preempt_disable_notrace();
	cpu = smp_processor_id();
	src = &hv_clock[cpu].pvti;
	ret = pvclock_clocksource_read(src);
	preempt_enable_notrace();
	return ret;
}

static u64 kvm_clock_get_cycles(struct clocksource *cs)
{
	return kvm_clock_read();
}

static u64 kvm_sched_clock_read(void)
{
	return kvm_clock_read() - kvm_sched_clock_offset;
}

static inline void kvm_sched_clock_init(bool stable)
{
	if (!stable) {
		pv_time_ops.sched_clock = kvm_clock_read;
		clear_sched_clock_stable();
		return;
	}

	kvm_sched_clock_offset = kvm_clock_read();
	pv_time_ops.sched_clock = kvm_sched_clock_read;

	printk(KERN_INFO "kvm-clock: using sched offset of %llu cycles\n",
			kvm_sched_clock_offset);

	BUILD_BUG_ON(sizeof(kvm_sched_clock_offset) >
	         sizeof(((struct pvclock_vcpu_time_info *)NULL)->system_time));
}

/*
 * If we don't do that, there is the possibility that the guest
 * will calibrate under heavy load - thus, getting a lower lpj -
 * and execute the delays themselves without load. This is wrong,
 * because no delay loop can finish beforehand.
 * Any heuristics is subject to fail, because ultimately, a large
 * poll of guests can be running and trouble each other. So we preset
 * lpj here
 */
static unsigned long kvm_get_tsc_khz(void)
{
	struct pvclock_vcpu_time_info *src;
	int cpu;
	unsigned long tsc_khz;

	cpu = get_cpu();
	src = &hv_clock[cpu].pvti;
	tsc_khz = pvclock_tsc_khz(src);
	put_cpu();
	setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
	return tsc_khz;
}

static void kvm_get_preset_lpj(void)
{
	unsigned long khz;
	u64 lpj;

	khz = kvm_get_tsc_khz();

	lpj = ((u64)khz * 1000);
	do_div(lpj, HZ);
	preset_lpj = lpj;
}

bool kvm_check_and_clear_guest_paused(void)
{
	bool ret = false;
	struct pvclock_vcpu_time_info *src;
	int cpu = smp_processor_id();

	if (!hv_clock)
		return ret;

	src = &hv_clock[cpu].pvti;
	if ((src->flags & PVCLOCK_GUEST_STOPPED) != 0) {
		src->flags &= ~PVCLOCK_GUEST_STOPPED;
		pvclock_touch_watchdogs();
		ret = true;
	}

	return ret;
}

struct clocksource kvm_clock = {
	.name = "kvm-clock",
	.read = kvm_clock_get_cycles,
	.rating = 400,
	.mask = CLOCKSOURCE_MASK(64),
	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
EXPORT_SYMBOL_GPL(kvm_clock);

int kvm_register_clock(char *txt)
{
	int cpu = smp_processor_id();
	int low, high, ret;
	struct pvclock_vcpu_time_info *src;

	if (!hv_clock)
		return 0;

	src = &hv_clock[cpu].pvti;
	low = (int)slow_virt_to_phys(src) | 1;
	high = ((u64)slow_virt_to_phys(src) >> 32);
	ret = native_write_msr_safe(msr_kvm_system_time, low, high);
	printk(KERN_INFO "kvm-clock: cpu %d, msr %x:%x, %s\n",
	       cpu, high, low, txt);

	return ret;
}

static void kvm_save_sched_clock_state(void)
{
}

static void kvm_restore_sched_clock_state(void)
{
	kvm_register_clock("primary cpu clock, resume");
}

#ifdef CONFIG_X86_LOCAL_APIC
static void kvm_setup_secondary_clock(void)
{
	/*
	 * Now that the first cpu already had this clocksource initialized,
	 * we shouldn't fail.
	 */
	WARN_ON(kvm_register_clock("secondary cpu clock"));
}
#endif

/*
 * After the clock is registered, the host will keep writing to the
 * registered memory location. If the guest happens to shutdown, this memory
 * won't be valid. In cases like kexec, in which you install a new kernel, this
 * means a random memory location will be kept being written. So before any
 * kind of shutdown from our side, we unregister the clock by writing anything
 * that does not have the 'enable' bit set in the msr
 */
#ifdef CONFIG_KEXEC_CORE
static void kvm_crash_shutdown(struct pt_regs *regs)
{
	native_write_msr(msr_kvm_system_time, 0, 0);
	kvm_disable_steal_time();
	native_machine_crash_shutdown(regs);
}
#endif

static void kvm_shutdown(void)
{
	native_write_msr(msr_kvm_system_time, 0, 0);
	kvm_disable_steal_time();
	native_machine_shutdown();
}

void __init kvmclock_init(void)
{
	struct pvclock_vcpu_time_info *vcpu_time;
	int cpu;
	u8 flags;

	if (!kvm_para_available())
		return;

	if (kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2)) {
		msr_kvm_system_time = MSR_KVM_SYSTEM_TIME_NEW;
		msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK_NEW;
	} else if (!(kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE)))
		return;

	hv_clock = (struct pvclock_vsyscall_time_info *)hv_clock_mem;

	if (kvm_register_clock("primary cpu clock")) {
		hv_clock = NULL;
		return;
	}

	printk(KERN_INFO "kvm-clock: Using msrs %x and %x",
		msr_kvm_system_time, msr_kvm_wall_clock);

	pvclock_set_pvti_cpu0_va(hv_clock);

	if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE_STABLE_BIT))
		pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT);

	cpu = get_cpu();
	vcpu_time = &hv_clock[cpu].pvti;
	flags = pvclock_read_flags(vcpu_time);

	kvm_sched_clock_init(flags & PVCLOCK_TSC_STABLE_BIT);
	put_cpu();

	x86_platform.calibrate_tsc = kvm_get_tsc_khz;
	x86_platform.calibrate_cpu = kvm_get_tsc_khz;
	x86_platform.get_wallclock = kvm_get_wallclock;
	x86_platform.set_wallclock = kvm_set_wallclock;
#ifdef CONFIG_X86_LOCAL_APIC
	x86_cpuinit.early_percpu_clock_init =
		kvm_setup_secondary_clock;
#endif
	x86_platform.save_sched_clock_state = kvm_save_sched_clock_state;
	x86_platform.restore_sched_clock_state = kvm_restore_sched_clock_state;
	machine_ops.shutdown  = kvm_shutdown;
#ifdef CONFIG_KEXEC_CORE
	machine_ops.crash_shutdown  = kvm_crash_shutdown;
#endif
	kvm_get_preset_lpj();
	clocksource_register_hz(&kvm_clock, NSEC_PER_SEC);
	pv_info.name = "KVM";
}

int __init kvm_setup_vsyscall_timeinfo(void)
{
#ifdef CONFIG_X86_64
	int cpu;
	u8 flags;
	struct pvclock_vcpu_time_info *vcpu_time;

	if (!hv_clock)
		return 0;

	cpu = get_cpu();

	vcpu_time = &hv_clock[cpu].pvti;
	flags = pvclock_read_flags(vcpu_time);

	put_cpu();

	if (!(flags & PVCLOCK_TSC_STABLE_BIT))
		return 1;

	kvm_clock.archdata.vclock_mode = VCLOCK_PVCLOCK;
#endif
	return 0;
}
Commit	Line	Data
790c73f6 GOC	1	/* KVM paravirtual clock driver. A clocksource implementation
	2	Copyright (C) 2008 Glauber de Oliveira Costa, Red Hat Inc.
	3
	4	This program is free software; you can redistribute it and/or modify
	5	it under the terms of the GNU General Public License as published by
	6	the Free Software Foundation; either version 2 of the License, or
	7	(at your option) any later version.
	8
	9	This program is distributed in the hope that it will be useful,
	10	but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	GNU General Public License for more details.
	13
	14	You should have received a copy of the GNU General Public License
	15	along with this program; if not, write to the Free Software
	16	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	17	*/
	18
	19	#include <linux/clocksource.h>
	20	#include <linux/kvm_para.h>
f6e16d5a	21	#include <asm/pvclock.h>
790c73f6 GOC	22	#include <asm/msr.h>
	23	#include <asm/apic.h>
	24	#include <linux/percpu.h>
3b5d56b9	25	#include <linux/hardirq.h>
0ad83caa	26	#include <linux/sched.h>
e6017571	27	#include <linux/sched/clock.h>
368a540e	28	#include <linux/mm.h>
736decac	29
819aeee0	30	#include <asm/mem_encrypt.h>
736decac	31	#include <asm/x86_init.h>
1e977aa1	32	#include <asm/reboot.h>
f4066c2b	33	#include <asm/kvmclock.h>
790c73f6	34
404f6aac	35	static int kvmclock __ro_after_init = 1;
838815a7 GC	36	static int msr_kvm_system_time = MSR_KVM_SYSTEM_TIME;
838815a7 GC	37	static int msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK;
a5a1d1c2	38	static u64 kvm_sched_clock_offset;
790c73f6 GOC	39
	40	static int parse_no_kvmclock(char *arg)
	41	{
	42	kvmclock = 0;
	43	return 0;
	44	}
	45	early_param("no-kvmclock", parse_no_kvmclock);
	46
368a540e PT	47	/* Aligned to page sizes to match whats mapped via vsyscalls to userspace */
368a540e PT	48	#define HV_CLOCK_SIZE (sizeof(struct pvclock_vsyscall_time_info) * NR_CPUS)
368a540e PT	49
368a540e PT	50	static u8 hv_clock_mem[PAGE_ALIGN(HV_CLOCK_SIZE)] __aligned(PAGE_SIZE);
368a540e	51
790c73f6	52	/* The hypervisor will put information about time periodically here */
3dc4f7cf	53	static struct pvclock_vsyscall_time_info *hv_clock;
7ef363a3	54	static struct pvclock_wall_clock wall_clock;
790c73f6	55
790c73f6 GOC	56	/*
	57	* The wallclock is the time of day when we booted. Since then, some time may
	58	* have elapsed since the hypervisor wrote the data. So we try to account for
	59	* that with system time
	60	*/
e27c4929	61	static void kvm_get_wallclock(struct timespec64 *now)
790c73f6	62	{
f6e16d5a	63	struct pvclock_vcpu_time_info *vcpu_time;
790c73f6	64	int low, high;
7069ed67	65	int cpu;
790c73f6	66
7ef363a3 TG	67	low = (int)slow_virt_to_phys(&wall_clock);
7ef363a3 TG	68	high = ((u64)slow_virt_to_phys(&wall_clock) >> 32);
838815a7 GC	69
838815a7 GC	70	native_write_msr(msr_kvm_wall_clock, low, high);
790c73f6	71
c6338ce4	72	cpu = get_cpu();
7069ed67	73
3dc4f7cf	74	vcpu_time = &hv_clock[cpu].pvti;
7ef363a3	75	pvclock_read_wallclock(&wall_clock, vcpu_time, now);
7069ed67	76
c6338ce4	77	put_cpu();
790c73f6 GOC	78	}
790c73f6 GOC	79
e27c4929	80	static int kvm_set_wallclock(const struct timespec64 *now)
790c73f6	81	{
00875520	82	return -ENODEV;
790c73f6 GOC	83	}
790c73f6 GOC	84
a5a1d1c2	85	static u64 kvm_clock_read(void)
790c73f6	86	{
f6e16d5a	87	struct pvclock_vcpu_time_info *src;
a5a1d1c2	88	u64 ret;
7069ed67	89	int cpu;
790c73f6	90
95ef1e52	91	preempt_disable_notrace();
7069ed67	92	cpu = smp_processor_id();
3dc4f7cf	93	src = &hv_clock[cpu].pvti;
f6e16d5a	94	ret = pvclock_clocksource_read(src);
95ef1e52	95	preempt_enable_notrace();
f6e16d5a	96	return ret;
790c73f6	97	}
f6e16d5a	98
a5a1d1c2	99	static u64 kvm_clock_get_cycles(struct clocksource *cs)
8e19608e MD	100	{
	101	return kvm_clock_read();
	102	}
	103
a5a1d1c2	104	static u64 kvm_sched_clock_read(void)
72c930dc RK	105	{
	106	return kvm_clock_read() - kvm_sched_clock_offset;
	107	}
	108
	109	static inline void kvm_sched_clock_init(bool stable)
	110	{
	111	if (!stable) {
	112	pv_time_ops.sched_clock = kvm_clock_read;
acb04058	113	clear_sched_clock_stable();
72c930dc RK	114	return;
	115	}
	116
	117	kvm_sched_clock_offset = kvm_clock_read();
	118	pv_time_ops.sched_clock = kvm_sched_clock_read;
72c930dc RK	119
	120	printk(KERN_INFO "kvm-clock: using sched offset of %llu cycles\n",
	121	kvm_sched_clock_offset);
	122
	123	BUILD_BUG_ON(sizeof(kvm_sched_clock_offset) >
	124	sizeof(((struct pvclock_vcpu_time_info *)NULL)->system_time));
	125	}
	126
0293615f GC	127	/*
	128	* If we don't do that, there is the possibility that the guest
	129	* will calibrate under heavy load - thus, getting a lower lpj -
	130	* and execute the delays themselves without load. This is wrong,
	131	* because no delay loop can finish beforehand.
	132	* Any heuristics is subject to fail, because ultimately, a large
	133	* poll of guests can be running and trouble each other. So we preset
	134	* lpj here
	135	*/
	136	static unsigned long kvm_get_tsc_khz(void)
	137	{
e93353c9	138	struct pvclock_vcpu_time_info *src;
7069ed67 MT	139	int cpu;
	140	unsigned long tsc_khz;
	141
c6338ce4	142	cpu = get_cpu();
3dc4f7cf	143	src = &hv_clock[cpu].pvti;
7069ed67	144	tsc_khz = pvclock_tsc_khz(src);
c6338ce4	145	put_cpu();
e10f7805	146	setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
7069ed67	147	return tsc_khz;
0293615f GC	148	}
	149
	150	static void kvm_get_preset_lpj(void)
	151	{
0293615f GC	152	unsigned long khz;
	153	u64 lpj;
	154
e93353c9	155	khz = kvm_get_tsc_khz();
0293615f GC	156
	157	lpj = ((u64)khz * 1000);
	158	do_div(lpj, HZ);
	159	preset_lpj = lpj;
	160	}
	161
3b5d56b9 EM	162	bool kvm_check_and_clear_guest_paused(void)
	163	{
	164	bool ret = false;
	165	struct pvclock_vcpu_time_info *src;
7069ed67 MT	166	int cpu = smp_processor_id();
	167
	168	if (!hv_clock)
	169	return ret;
3b5d56b9	170
3dc4f7cf	171	src = &hv_clock[cpu].pvti;
3b5d56b9	172	if ((src->flags & PVCLOCK_GUEST_STOPPED) != 0) {
7069ed67	173	src->flags &= ~PVCLOCK_GUEST_STOPPED;
d63285e9	174	pvclock_touch_watchdogs();
3b5d56b9 EM	175	ret = true;
	176	}
	177
	178	return ret;
	179	}
3b5d56b9	180
f4066c2b	181	struct clocksource kvm_clock = {
790c73f6	182	.name = "kvm-clock",
8e19608e	183	.read = kvm_clock_get_cycles,
790c73f6 GOC	184	.rating = 400,
790c73f6 GOC	185	.mask = CLOCKSOURCE_MASK(64),
790c73f6 GOC	186	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
790c73f6 GOC	187	};
f4066c2b	188	EXPORT_SYMBOL_GPL(kvm_clock);
790c73f6	189
ca3f1017	190	int kvm_register_clock(char *txt)
790c73f6 GOC	191	{
790c73f6 GOC	192	int cpu = smp_processor_id();
19b6a85b	193	int low, high, ret;
fe1140cc JK	194	struct pvclock_vcpu_time_info *src;
	195
	196	if (!hv_clock)
	197	return 0;
19b6a85b	198
fe1140cc	199	src = &hv_clock[cpu].pvti;
5dfd486c DH	200	low = (int)slow_virt_to_phys(src) \| 1;
5dfd486c DH	201	high = ((u64)slow_virt_to_phys(src) >> 32);
19b6a85b	202	ret = native_write_msr_safe(msr_kvm_system_time, low, high);
f6e16d5a GH	203	printk(KERN_INFO "kvm-clock: cpu %d, msr %x:%x, %s\n",
f6e16d5a GH	204	cpu, high, low, txt);
838815a7	205
19b6a85b	206	return ret;
790c73f6 GOC	207	}
790c73f6 GOC	208
b74f05d6 MT	209	static void kvm_save_sched_clock_state(void)
	210	{
	211	}
	212
	213	static void kvm_restore_sched_clock_state(void)
	214	{
	215	kvm_register_clock("primary cpu clock, resume");
	216	}
	217
b8ba5f10	218	#ifdef CONFIG_X86_LOCAL_APIC
148f9bb8	219	static void kvm_setup_secondary_clock(void)
790c73f6 GOC	220	{
	221	/*
	222	* Now that the first cpu already had this clocksource initialized,
	223	* we shouldn't fail.
	224	*/
f6e16d5a	225	WARN_ON(kvm_register_clock("secondary cpu clock"));
790c73f6	226	}
b8ba5f10	227	#endif
790c73f6	228
1e977aa1 GC	229	/*
	230	* After the clock is registered, the host will keep writing to the
	231	* registered memory location. If the guest happens to shutdown, this memory
	232	* won't be valid. In cases like kexec, in which you install a new kernel, this
	233	* means a random memory location will be kept being written. So before any
6a6256f9	234	* kind of shutdown from our side, we unregister the clock by writing anything
1e977aa1 GC	235	* that does not have the 'enable' bit set in the msr
1e977aa1 GC	236	*/
2965faa5	237	#ifdef CONFIG_KEXEC_CORE
1e977aa1 GC	238	static void kvm_crash_shutdown(struct pt_regs *regs)
1e977aa1 GC	239	{
838815a7	240	native_write_msr(msr_kvm_system_time, 0, 0);
d910f5c1	241	kvm_disable_steal_time();
1e977aa1 GC	242	native_machine_crash_shutdown(regs);
	243	}
	244	#endif
	245
	246	static void kvm_shutdown(void)
	247	{
838815a7	248	native_write_msr(msr_kvm_system_time, 0, 0);
d910f5c1	249	kvm_disable_steal_time();
1e977aa1 GC	250	native_machine_shutdown();
	251	}
	252
790c73f6 GOC	253	void __init kvmclock_init(void)
790c73f6 GOC	254	{
0ad83caa	255	struct pvclock_vcpu_time_info *vcpu_time;
368a540e	256	int cpu;
0ad83caa	257	u8 flags;
ed55705d	258
790c73f6 GOC	259	if (!kvm_para_available())
	260	return;
	261
838815a7 GC	262	if (kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2)) {
	263	msr_kvm_system_time = MSR_KVM_SYSTEM_TIME_NEW;
	264	msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK_NEW;
	265	} else if (!(kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE)))
	266	return;
	267
368a540e	268	hv_clock = (struct pvclock_vsyscall_time_info *)hv_clock_mem;
7069ed67	269
0d75de4a	270	if (kvm_register_clock("primary cpu clock")) {
7069ed67	271	hv_clock = NULL;
838815a7	272	return;
7069ed67	273	}
72c930dc	274
819aeee0 BS	275	printk(KERN_INFO "kvm-clock: Using msrs %x and %x",
	276	msr_kvm_system_time, msr_kvm_wall_clock);
	277
94ffba48 RK	278	pvclock_set_pvti_cpu0_va(hv_clock);
94ffba48 RK	279
72c930dc RK	280	if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE_STABLE_BIT))
	281	pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT);
	282
	283	cpu = get_cpu();
	284	vcpu_time = &hv_clock[cpu].pvti;
	285	flags = pvclock_read_flags(vcpu_time);
	286
	287	kvm_sched_clock_init(flags & PVCLOCK_TSC_STABLE_BIT);
	288	put_cpu();
	289
838815a7	290	x86_platform.calibrate_tsc = kvm_get_tsc_khz;
a4497a86	291	x86_platform.calibrate_cpu = kvm_get_tsc_khz;
838815a7 GC	292	x86_platform.get_wallclock = kvm_get_wallclock;
838815a7 GC	293	x86_platform.set_wallclock = kvm_set_wallclock;
b8ba5f10	294	#ifdef CONFIG_X86_LOCAL_APIC
df156f90	295	x86_cpuinit.early_percpu_clock_init =
838815a7	296	kvm_setup_secondary_clock;
b8ba5f10	297	#endif
b74f05d6 MT	298	x86_platform.save_sched_clock_state = kvm_save_sched_clock_state;
b74f05d6 MT	299	x86_platform.restore_sched_clock_state = kvm_restore_sched_clock_state;
838815a7	300	machine_ops.shutdown = kvm_shutdown;
2965faa5	301	#ifdef CONFIG_KEXEC_CORE
838815a7	302	machine_ops.crash_shutdown = kvm_crash_shutdown;
1e977aa1	303	#endif
838815a7	304	kvm_get_preset_lpj();
b01cc1b0	305	clocksource_register_hz(&kvm_clock, NSEC_PER_SEC);
838815a7	306	pv_info.name = "KVM";
790c73f6	307	}
3dc4f7cf MT	308
	309	int __init kvm_setup_vsyscall_timeinfo(void)
	310	{
	311	#ifdef CONFIG_X86_64
	312	int cpu;
3dc4f7cf MT	313	u8 flags;
3dc4f7cf MT	314	struct pvclock_vcpu_time_info *vcpu_time;
3dc4f7cf	315
fe1140cc JK	316	if (!hv_clock)
	317	return 0;
	318
c6338ce4	319	cpu = get_cpu();
3dc4f7cf MT	320
	321	vcpu_time = &hv_clock[cpu].pvti;
	322	flags = pvclock_read_flags(vcpu_time);
	323
c6338ce4	324	put_cpu();
3dc4f7cf	325
94ffba48 RK	326	if (!(flags & PVCLOCK_TSC_STABLE_BIT))
	327	return 1;
	328
3dc4f7cf MT	329	kvm_clock.archdata.vclock_mode = VCLOCK_PVCLOCK;
	330	#endif
	331	return 0;
	332	}