Orange Pi5 kernel

 // SPDX-License-Identifier: GPL-2.0-or-later
/*  KVM paravirtual clock driver. A clocksource implementation
    Copyright (C) 2008 Glauber de Oliveira Costa, Red Hat Inc.
*/
 
#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/cpuhotplug.h>
#include <linux/sched.h>
#include <linux/sched/clock.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/set_memory.h>
 
#include <asm/hypervisor.h>
#include <asm/mem_encrypt.h>
#include <asm/x86_init.h>
#include <asm/kvmclock.h>
 
static int kvmclock __initdata = 1;
static int kvmclock_vsyscall __initdata = 1;
static int msr_kvm_system_time __ro_after_init = MSR_KVM_SYSTEM_TIME;
static int msr_kvm_wall_clock __ro_after_init = MSR_KVM_WALL_CLOCK;
static u64 kvm_sched_clock_offset __ro_after_init;
 
static int __init parse_no_kvmclock(char *arg)
{
<------>kvmclock = 0;
<------>return 0;
}
early_param("no-kvmclock", parse_no_kvmclock);
 
static int __init parse_no_kvmclock_vsyscall(char *arg)
{
<------>kvmclock_vsyscall = 0;
<------>return 0;
}
early_param("no-kvmclock-vsyscall", parse_no_kvmclock_vsyscall);
 
/* Aligned to page sizes to match whats mapped via vsyscalls to userspace */
#define HV_CLOCK_SIZE	(sizeof(struct pvclock_vsyscall_time_info) * NR_CPUS)
#define HVC_BOOT_ARRAY_SIZE \
<------>(PAGE_SIZE / sizeof(struct pvclock_vsyscall_time_info))
 
static struct pvclock_vsyscall_time_info
<------><------><------>hv_clock_boot[HVC_BOOT_ARRAY_SIZE] __bss_decrypted __aligned(PAGE_SIZE);
static struct pvclock_wall_clock wall_clock __bss_decrypted;
static struct pvclock_vsyscall_time_info *hvclock_mem;
DEFINE_PER_CPU(struct pvclock_vsyscall_time_info *, hv_clock_per_cpu);
EXPORT_PER_CPU_SYMBOL_GPL(hv_clock_per_cpu);
 
/*
 * 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)
{
<------>wrmsrl(msr_kvm_wall_clock, slow_virt_to_phys(&wall_clock));
<------>preempt_disable();
<------>pvclock_read_wallclock(&wall_clock, this_cpu_pvti(), now);
<------>preempt_enable();
}
 
static int kvm_set_wallclock(const struct timespec64 *now)
{
<------>return -ENODEV;
}
 
static u64 kvm_clock_read(void)
{
<------>u64 ret;
 
<------>preempt_disable_notrace();
<------>ret = pvclock_clocksource_read(this_cpu_pvti());
<------>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)
<------><------>clear_sched_clock_stable();
<------>kvm_sched_clock_offset = kvm_clock_read();
<------>pv_ops.time.sched_clock = kvm_sched_clock_read;
 
<------>pr_info("kvm-clock: using sched offset of %llu cycles",
<------><------>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)
{
<------>setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
<------>return pvclock_tsc_khz(this_cpu_pvti());
}
 
static void __init 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)
{
<------>struct pvclock_vsyscall_time_info *src = this_cpu_hvclock();
<------>bool ret = false;
 
<------>if (!src)
<------><------>return ret;
 
<------>if ((src->pvti.flags & PVCLOCK_GUEST_STOPPED) != 0) {
<------><------>src->pvti.flags &= ~PVCLOCK_GUEST_STOPPED;
<------><------>pvclock_touch_watchdogs();
<------><------>ret = true;
<------>}
<------>return ret;
}
 
static int kvm_cs_enable(struct clocksource *cs)
{
<------>vclocks_set_used(VDSO_CLOCKMODE_PVCLOCK);
<------>return 0;
}
 
struct clocksource kvm_clock = {
<------>.name	= "kvm-clock",
<------>.read	= kvm_clock_get_cycles,
<------>.rating	= 400,
<------>.mask	= CLOCKSOURCE_MASK(64),
<------>.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
<------>.enable	= kvm_cs_enable,
};
EXPORT_SYMBOL_GPL(kvm_clock);
 
static void kvm_register_clock(char *txt)
{
<------>struct pvclock_vsyscall_time_info *src = this_cpu_hvclock();
<------>u64 pa;
 
<------>if (!src)
<------><------>return;
 
<------>pa = slow_virt_to_phys(&src->pvti) | 0x01ULL;
<------>wrmsrl(msr_kvm_system_time, pa);
<------>pr_info("kvm-clock: cpu %d, msr %llx, %s", smp_processor_id(), pa, txt);
}
 
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)
{
<------>kvm_register_clock("secondary cpu clock");
}
#endif
 
void kvmclock_disable(void)
{
<------>native_write_msr(msr_kvm_system_time, 0, 0);
}
 
static void __init kvmclock_init_mem(void)
{
<------>unsigned long ncpus;
<------>unsigned int order;
<------>struct page *p;
<------>int r;
 
<------>if (HVC_BOOT_ARRAY_SIZE >= num_possible_cpus())
<------><------>return;
 
<------>ncpus = num_possible_cpus() - HVC_BOOT_ARRAY_SIZE;
<------>order = get_order(ncpus * sizeof(*hvclock_mem));
 
<------>p = alloc_pages(GFP_KERNEL, order);
<------>if (!p) {
<------><------>pr_warn("%s: failed to alloc %d pages", __func__, (1U << order));
<------><------>return;
<------>}
 
<------>hvclock_mem = page_address(p);
 
<------>/*
<------> * hvclock is shared between the guest and the hypervisor, must
<------> * be mapped decrypted.
<------> */
<------>if (sev_active()) {
<------><------>r = set_memory_decrypted((unsigned long) hvclock_mem,
<------><------><------><------><------> 1UL << order);
<------><------>if (r) {
<------><------><------>__free_pages(p, order);
<------><------><------>hvclock_mem = NULL;
<------><------><------>pr_warn("kvmclock: set_memory_decrypted() failed. Disabling\n");
<------><------><------>return;
<------><------>}
<------>}
 
<------>memset(hvclock_mem, 0, PAGE_SIZE << order);
}
 
static int __init kvm_setup_vsyscall_timeinfo(void)
{
<------>kvmclock_init_mem();
 
#ifdef CONFIG_X86_64
<------>if (per_cpu(hv_clock_per_cpu, 0) && kvmclock_vsyscall) {
<------><------>u8 flags;
 
<------><------>flags = pvclock_read_flags(&hv_clock_boot[0].pvti);
<------><------>if (!(flags & PVCLOCK_TSC_STABLE_BIT))
<------><------><------>return 0;
 
<------><------>kvm_clock.vdso_clock_mode = VDSO_CLOCKMODE_PVCLOCK;
<------>}
#endif
 
<------>return 0;
}
early_initcall(kvm_setup_vsyscall_timeinfo);
 
static int kvmclock_setup_percpu(unsigned int cpu)
{
<------>struct pvclock_vsyscall_time_info *p = per_cpu(hv_clock_per_cpu, cpu);
 
<------>/*
<------> * The per cpu area setup replicates CPU0 data to all cpu
<------> * pointers. So carefully check. CPU0 has been set up in init
<------> * already.
<------> */
<------>if (!cpu || (p && p != per_cpu(hv_clock_per_cpu, 0)))
<------><------>return 0;
 
<------>/* Use the static page for the first CPUs, allocate otherwise */
<------>if (cpu < HVC_BOOT_ARRAY_SIZE)
<------><------>p = &hv_clock_boot[cpu];
<------>else if (hvclock_mem)
<------><------>p = hvclock_mem + cpu - HVC_BOOT_ARRAY_SIZE;
<------>else
<------><------>return -ENOMEM;
 
<------>per_cpu(hv_clock_per_cpu, cpu) = p;
<------>return p ? 0 : -ENOMEM;
}
 
void __init kvmclock_init(void)
{
<------>u8 flags;
 
<------>if (!kvm_para_available() || !kvmclock)
<------><------>return;
 
<------>if (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 (!kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE)) {
<------><------>return;
<------>}
 
<------>if (cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "kvmclock:setup_percpu",
<------><------><------>      kvmclock_setup_percpu, NULL) < 0) {
<------><------>return;
<------>}
 
<------>pr_info("kvm-clock: Using msrs %x and %x",
<------><------>msr_kvm_system_time, msr_kvm_wall_clock);
 
<------>this_cpu_write(hv_clock_per_cpu, &hv_clock_boot[0]);
<------>kvm_register_clock("primary cpu clock");
<------>pvclock_set_pvti_cpu0_va(hv_clock_boot);
 
<------>if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE_STABLE_BIT))
<------><------>pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT);
 
<------>flags = pvclock_read_flags(&hv_clock_boot[0].pvti);
<------>kvm_sched_clock_init(flags & PVCLOCK_TSC_STABLE_BIT);
 
<------>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;
<------>kvm_get_preset_lpj();
 
<------>/*
<------> * X86_FEATURE_NONSTOP_TSC is TSC runs at constant rate
<------> * with P/T states and does not stop in deep C-states.
<------> *
<------> * Invariant TSC exposed by host means kvmclock is not necessary:
<------> * can use TSC as clocksource.
<------> *
<------> */
<------>if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) &&
<------>    boot_cpu_has(X86_FEATURE_NONSTOP_TSC) &&
<------>    !check_tsc_unstable())
<------><------>kvm_clock.rating = 299;
 
<------>clocksource_register_hz(&kvm_clock, NSEC_PER_SEC);
<------>pv_info.name = "KVM";
}

	// SPDX-License-Identifier: GPL-2.0-or-later
	/* KVM paravirtual clock driver. A clocksource implementation
	Copyright (C) 2008 Glauber de Oliveira Costa, Red Hat Inc.
	*/

	#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/cpuhotplug.h>
	#include <linux/sched.h>
	#include <linux/sched/clock.h>
	#include <linux/mm.h>
	#include <linux/slab.h>
	#include <linux/set_memory.h>

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

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

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

	static int __init parse_no_kvmclock_vsyscall(char *arg)
	{
	<------>kvmclock_vsyscall = 0;
	<------>return 0;
	}
	early_param("no-kvmclock-vsyscall", parse_no_kvmclock_vsyscall);

	/* Aligned to page sizes to match whats mapped via vsyscalls to userspace */
	#define HV_CLOCK_SIZE (sizeof(struct pvclock_vsyscall_time_info) * NR_CPUS)
	#define HVC_BOOT_ARRAY_SIZE \
	<------>(PAGE_SIZE / sizeof(struct pvclock_vsyscall_time_info))

	static struct pvclock_vsyscall_time_info
	<------><------><------>hv_clock_boot[HVC_BOOT_ARRAY_SIZE] __bss_decrypted __aligned(PAGE_SIZE);
	static struct pvclock_wall_clock wall_clock __bss_decrypted;
	static struct pvclock_vsyscall_time_info *hvclock_mem;
	DEFINE_PER_CPU(struct pvclock_vsyscall_time_info *, hv_clock_per_cpu);
	EXPORT_PER_CPU_SYMBOL_GPL(hv_clock_per_cpu);

	/*
	* 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)
	{
	<------>wrmsrl(msr_kvm_wall_clock, slow_virt_to_phys(&wall_clock));
	<------>preempt_disable();
	<------>pvclock_read_wallclock(&wall_clock, this_cpu_pvti(), now);
	<------>preempt_enable();
	}

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

	static u64 kvm_clock_read(void)
	{
	<------>u64 ret;

	<------>preempt_disable_notrace();
	<------>ret = pvclock_clocksource_read(this_cpu_pvti());
	<------>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)
	<------><------>clear_sched_clock_stable();
	<------>kvm_sched_clock_offset = kvm_clock_read();
	<------>pv_ops.time.sched_clock = kvm_sched_clock_read;

	<------>pr_info("kvm-clock: using sched offset of %llu cycles",
	<------><------>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)
	{
	<------>setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
	<------>return pvclock_tsc_khz(this_cpu_pvti());
	}

	static void __init 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)
	{
	<------>struct pvclock_vsyscall_time_info *src = this_cpu_hvclock();
	<------>bool ret = false;

	<------>if (!src)
	<------><------>return ret;

	<------>if ((src->pvti.flags & PVCLOCK_GUEST_STOPPED) != 0) {
	<------><------>src->pvti.flags &= ~PVCLOCK_GUEST_STOPPED;
	<------><------>pvclock_touch_watchdogs();
	<------><------>ret = true;
	<------>}
	<------>return ret;
	}

	static int kvm_cs_enable(struct clocksource *cs)
	{
	<------>vclocks_set_used(VDSO_CLOCKMODE_PVCLOCK);
	<------>return 0;
	}

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

	static void kvm_register_clock(char *txt)
	{
	<------>struct pvclock_vsyscall_time_info *src = this_cpu_hvclock();
	<------>u64 pa;

	<------>if (!src)
	<------><------>return;

	<------>pa = slow_virt_to_phys(&src->pvti) \| 0x01ULL;
	<------>wrmsrl(msr_kvm_system_time, pa);
	<------>pr_info("kvm-clock: cpu %d, msr %llx, %s", smp_processor_id(), pa, txt);
	}

	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)
	{
	<------>kvm_register_clock("secondary cpu clock");
	}
	#endif

	void kvmclock_disable(void)
	{
	<------>native_write_msr(msr_kvm_system_time, 0, 0);
	}

	static void __init kvmclock_init_mem(void)
	{
	<------>unsigned long ncpus;
	<------>unsigned int order;
	<------>struct page *p;
	<------>int r;

	<------>if (HVC_BOOT_ARRAY_SIZE >= num_possible_cpus())
	<------><------>return;

	<------>ncpus = num_possible_cpus() - HVC_BOOT_ARRAY_SIZE;
	<------>order = get_order(ncpus * sizeof(*hvclock_mem));

	<------>p = alloc_pages(GFP_KERNEL, order);
	<------>if (!p) {
	<------><------>pr_warn("%s: failed to alloc %d pages", __func__, (1U << order));
	<------><------>return;
	<------>}

	<------>hvclock_mem = page_address(p);

	<------>/*
	<------> * hvclock is shared between the guest and the hypervisor, must
	<------> * be mapped decrypted.
	<------> */
	<------>if (sev_active()) {
	<------><------>r = set_memory_decrypted((unsigned long) hvclock_mem,
	<------><------><------><------><------> 1UL << order);
	<------><------>if (r) {
	<------><------><------>__free_pages(p, order);
	<------><------><------>hvclock_mem = NULL;
	<------><------><------>pr_warn("kvmclock: set_memory_decrypted() failed. Disabling\n");
	<------><------><------>return;
	<------><------>}
	<------>}

	<------>memset(hvclock_mem, 0, PAGE_SIZE << order);
	}

	static int __init kvm_setup_vsyscall_timeinfo(void)
	{
	<------>kvmclock_init_mem();

	#ifdef CONFIG_X86_64
	<------>if (per_cpu(hv_clock_per_cpu, 0) && kvmclock_vsyscall) {
	<------><------>u8 flags;

	<------><------>flags = pvclock_read_flags(&hv_clock_boot[0].pvti);
	<------><------>if (!(flags & PVCLOCK_TSC_STABLE_BIT))
	<------><------><------>return 0;

	<------><------>kvm_clock.vdso_clock_mode = VDSO_CLOCKMODE_PVCLOCK;
	<------>}
	#endif

	<------>return 0;
	}
	early_initcall(kvm_setup_vsyscall_timeinfo);

	static int kvmclock_setup_percpu(unsigned int cpu)
	{
	<------>struct pvclock_vsyscall_time_info *p = per_cpu(hv_clock_per_cpu, cpu);

	<------>/*
	<------> * The per cpu area setup replicates CPU0 data to all cpu
	<------> * pointers. So carefully check. CPU0 has been set up in init
	<------> * already.
	<------> */
	<------>if (!cpu \|\| (p && p != per_cpu(hv_clock_per_cpu, 0)))
	<------><------>return 0;

	<------>/* Use the static page for the first CPUs, allocate otherwise */
	<------>if (cpu < HVC_BOOT_ARRAY_SIZE)
	<------><------>p = &hv_clock_boot[cpu];
	<------>else if (hvclock_mem)
	<------><------>p = hvclock_mem + cpu - HVC_BOOT_ARRAY_SIZE;
	<------>else
	<------><------>return -ENOMEM;

	<------>per_cpu(hv_clock_per_cpu, cpu) = p;
	<------>return p ? 0 : -ENOMEM;
	}

	void __init kvmclock_init(void)
	{
	<------>u8 flags;

	<------>if (!kvm_para_available() \|\| !kvmclock)
	<------><------>return;

	<------>if (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 (!kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE)) {
	<------><------>return;
	<------>}

	<------>if (cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "kvmclock:setup_percpu",
	<------><------><------> kvmclock_setup_percpu, NULL) < 0) {
	<------><------>return;
	<------>}

	<------>pr_info("kvm-clock: Using msrs %x and %x",
	<------><------>msr_kvm_system_time, msr_kvm_wall_clock);

	<------>this_cpu_write(hv_clock_per_cpu, &hv_clock_boot[0]);
	<------>kvm_register_clock("primary cpu clock");
	<------>pvclock_set_pvti_cpu0_va(hv_clock_boot);

	<------>if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE_STABLE_BIT))
	<------><------>pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT);

	<------>flags = pvclock_read_flags(&hv_clock_boot[0].pvti);
	<------>kvm_sched_clock_init(flags & PVCLOCK_TSC_STABLE_BIT);

	<------>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;
	<------>kvm_get_preset_lpj();

	<------>/*
	<------> * X86_FEATURE_NONSTOP_TSC is TSC runs at constant rate
	<------> * with P/T states and does not stop in deep C-states.
	<------> *
	<------> * Invariant TSC exposed by host means kvmclock is not necessary:
	<------> * can use TSC as clocksource.
	<------> *
	<------> */
	<------>if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) &&
	<------> boot_cpu_has(X86_FEATURE_NONSTOP_TSC) &&
	<------> !check_tsc_unstable())
	<------><------>kvm_clock.rating = 299;

	<------>clocksource_register_hz(&kvm_clock, NSEC_PER_SEC);
	<------>pv_info.name = "KVM";
	}