[deliverable/linux.git] / arch / x86 / kernel / kvm.c

/*
 * KVM paravirt_ops implementation
 *
 * 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, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
 * Copyright IBM Corporation, 2007
 *   Authors: Anthony Liguori <aliguori@us.ibm.com>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/kvm_para.h>
#include <linux/cpu.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/hardirq.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/hash.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/kprobes.h>
#include <asm/timer.h>
#include <asm/cpu.h>
#include <asm/traps.h>
#include <asm/desc.h>
#include <asm/tlbflush.h>
#include <asm/idle.h>
#include <asm/apic.h>
#include <asm/apicdef.h>
#include <asm/hypervisor.h>

static int kvmapf = 1;

static int parse_no_kvmapf(char *arg)
{
        kvmapf = 0;
        return 0;
}

early_param("no-kvmapf", parse_no_kvmapf);

static int steal_acc = 1;
static int parse_no_stealacc(char *arg)
{
        steal_acc = 0;
        return 0;
}

early_param("no-steal-acc", parse_no_stealacc);

static DEFINE_PER_CPU(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);
static DEFINE_PER_CPU(struct kvm_steal_time, steal_time) __aligned(64);
static int has_steal_clock = 0;

/*
 * No need for any "IO delay" on KVM
 */
static void kvm_io_delay(void)
{
}

#define KVM_TASK_SLEEP_HASHBITS 8
#define KVM_TASK_SLEEP_HASHSIZE (1<<KVM_TASK_SLEEP_HASHBITS)

struct kvm_task_sleep_node {
	struct hlist_node link;
	wait_queue_head_t wq;
	u32 token;
	int cpu;
	bool halted;
};

static struct kvm_task_sleep_head {
	spinlock_t lock;
	struct hlist_head list;
} async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE];

static struct kvm_task_sleep_node *_find_apf_task(struct kvm_task_sleep_head *b,
						  u32 token)
{
	struct hlist_node *p;

	hlist_for_each(p, &b->list) {
		struct kvm_task_sleep_node *n =
			hlist_entry(p, typeof(*n), link);
		if (n->token == token)
			return n;
	}

	return NULL;
}

void kvm_async_pf_task_wait(u32 token)
{
	u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
	struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
	struct kvm_task_sleep_node n, *e;
	DEFINE_WAIT(wait);
	int cpu, idle;

	cpu = get_cpu();
	idle = idle_cpu(cpu);
	put_cpu();

	spin_lock(&b->lock);
	e = _find_apf_task(b, token);
	if (e) {
		/* dummy entry exist -> wake up was delivered ahead of PF */
		hlist_del(&e->link);
		kfree(e);
		spin_unlock(&b->lock);
		return;
	}

	n.token = token;
	n.cpu = smp_processor_id();
	n.halted = idle || preempt_count() > 1;
	init_waitqueue_head(&n.wq);
	hlist_add_head(&n.link, &b->list);
	spin_unlock(&b->lock);

	for (;;) {
		if (!n.halted)
			prepare_to_wait(&n.wq, &wait, TASK_UNINTERRUPTIBLE);
		if (hlist_unhashed(&n.link))
			break;

		if (!n.halted) {
			local_irq_enable();
			schedule();
			local_irq_disable();
		} else {
			/*
			 * We cannot reschedule. So halt.
			 */
			native_safe_halt();
			local_irq_disable();
		}
	}
	if (!n.halted)
		finish_wait(&n.wq, &wait);

	return;
}
EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait);

static void apf_task_wake_one(struct kvm_task_sleep_node *n)
{
	hlist_del_init(&n->link);
	if (n->halted)
		smp_send_reschedule(n->cpu);
	else if (waitqueue_active(&n->wq))
		wake_up(&n->wq);
}

static void apf_task_wake_all(void)
{
	int i;

	for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) {
		struct hlist_node *p, *next;
		struct kvm_task_sleep_head *b = &async_pf_sleepers[i];
		spin_lock(&b->lock);
		hlist_for_each_safe(p, next, &b->list) {
			struct kvm_task_sleep_node *n =
				hlist_entry(p, typeof(*n), link);
			if (n->cpu == smp_processor_id())
				apf_task_wake_one(n);
		}
		spin_unlock(&b->lock);
	}
}

void kvm_async_pf_task_wake(u32 token)
{
	u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
	struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
	struct kvm_task_sleep_node *n;

	if (token == ~0) {
		apf_task_wake_all();
		return;
	}

again:
	spin_lock(&b->lock);
	n = _find_apf_task(b, token);
	if (!n) {
		/*
		 * async PF was not yet handled.
		 * Add dummy entry for the token.
		 */
		n = kzalloc(sizeof(*n), GFP_ATOMIC);
		if (!n) {
			/*
			 * Allocation failed! Busy wait while other cpu
			 * handles async PF.
			 */
			spin_unlock(&b->lock);
			cpu_relax();
			goto again;
		}
		n->token = token;
		n->cpu = smp_processor_id();
		init_waitqueue_head(&n->wq);
		hlist_add_head(&n->link, &b->list);
	} else
		apf_task_wake_one(n);
	spin_unlock(&b->lock);
	return;
}
EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);

u32 kvm_read_and_reset_pf_reason(void)
{
	u32 reason = 0;

	if (__get_cpu_var(apf_reason).enabled) {
		reason = __get_cpu_var(apf_reason).reason;
		__get_cpu_var(apf_reason).reason = 0;
	}

	return reason;
}
EXPORT_SYMBOL_GPL(kvm_read_and_reset_pf_reason);

dotraplinkage void __kprobes
do_async_page_fault(struct pt_regs *regs, unsigned long error_code)
{
	switch (kvm_read_and_reset_pf_reason()) {
	default:
		do_page_fault(regs, error_code);
		break;
	case KVM_PV_REASON_PAGE_NOT_PRESENT:
		/* page is swapped out by the host. */
		rcu_irq_enter();
		exit_idle();
		kvm_async_pf_task_wait((u32)read_cr2());
		rcu_irq_exit();
		break;
	case KVM_PV_REASON_PAGE_READY:
		rcu_irq_enter();
		exit_idle();
		kvm_async_pf_task_wake((u32)read_cr2());
		rcu_irq_exit();
		break;
	}
}

static void __init paravirt_ops_setup(void)
{
	pv_info.name = "KVM";
	pv_info.paravirt_enabled = 1;

	if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
		pv_cpu_ops.io_delay = kvm_io_delay;

#ifdef CONFIG_X86_IO_APIC
	no_timer_check = 1;
#endif
}

static void kvm_register_steal_time(void)
{
	int cpu = smp_processor_id();
	struct kvm_steal_time *st = &per_cpu(steal_time, cpu);

	if (!has_steal_clock)
		return;

	memset(st, 0, sizeof(*st));

	wrmsrl(MSR_KVM_STEAL_TIME, (__pa(st) | KVM_MSR_ENABLED));
	printk(KERN_INFO "kvm-stealtime: cpu %d, msr %lx\n",
		cpu, __pa(st));
}

static DEFINE_PER_CPU(unsigned long, kvm_apic_eoi) = KVM_PV_EOI_DISABLED;

static void kvm_guest_apic_eoi_write(u32 reg, u32 val)
{
	/**
	 * This relies on __test_and_clear_bit to modify the memory
	 * in a way that is atomic with respect to the local CPU.
	 * The hypervisor only accesses this memory from the local CPU so
	 * there's no need for lock or memory barriers.
	 * An optimization barrier is implied in apic write.
	 */
	if (__test_and_clear_bit(KVM_PV_EOI_BIT, &__get_cpu_var(kvm_apic_eoi)))
		return;
	apic_write(APIC_EOI, APIC_EOI_ACK);
}

void __cpuinit kvm_guest_cpu_init(void)
{
	if (!kvm_para_available())
		return;

	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf) {
		u64 pa = __pa(&__get_cpu_var(apf_reason));

#ifdef CONFIG_PREEMPT
		pa |= KVM_ASYNC_PF_SEND_ALWAYS;
#endif
		wrmsrl(MSR_KVM_ASYNC_PF_EN, pa | KVM_ASYNC_PF_ENABLED);
		__get_cpu_var(apf_reason).enabled = 1;
		printk(KERN_INFO"KVM setup async PF for cpu %d\n",
		       smp_processor_id());
	}

	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) {
		unsigned long pa;
		/* Size alignment is implied but just to make it explicit. */
		BUILD_BUG_ON(__alignof__(kvm_apic_eoi) < 4);
		__get_cpu_var(kvm_apic_eoi) = 0;
		pa = __pa(&__get_cpu_var(kvm_apic_eoi)) | KVM_MSR_ENABLED;
		wrmsrl(MSR_KVM_PV_EOI_EN, pa);
	}

	if (has_steal_clock)
		kvm_register_steal_time();
}

static void kvm_pv_disable_apf(void)
{
	if (!__get_cpu_var(apf_reason).enabled)
		return;

	wrmsrl(MSR_KVM_ASYNC_PF_EN, 0);
	__get_cpu_var(apf_reason).enabled = 0;

	printk(KERN_INFO"Unregister pv shared memory for cpu %d\n",
	       smp_processor_id());
}

static void kvm_pv_guest_cpu_reboot(void *unused)
{
	/*
	 * We disable PV EOI before we load a new kernel by kexec,
	 * since MSR_KVM_PV_EOI_EN stores a pointer into old kernel's memory.
	 * New kernel can re-enable when it boots.
	 */
	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
		wrmsrl(MSR_KVM_PV_EOI_EN, 0);
	kvm_pv_disable_apf();
	kvm_disable_steal_time();
}

static int kvm_pv_reboot_notify(struct notifier_block *nb,
				unsigned long code, void *unused)
{
	if (code == SYS_RESTART)
		on_each_cpu(kvm_pv_guest_cpu_reboot, NULL, 1);
	return NOTIFY_DONE;
}

static struct notifier_block kvm_pv_reboot_nb = {
	.notifier_call = kvm_pv_reboot_notify,
};

static u64 kvm_steal_clock(int cpu)
{
	u64 steal;
	struct kvm_steal_time *src;
	int version;

	src = &per_cpu(steal_time, cpu);
	do {
		version = src->version;
		rmb();
		steal = src->steal;
		rmb();
	} while ((version & 1) || (version != src->version));

	return steal;
}

void kvm_disable_steal_time(void)
{
	if (!has_steal_clock)
		return;

	wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
}

#ifdef CONFIG_SMP
static void __init kvm_smp_prepare_boot_cpu(void)
{
	WARN_ON(kvm_register_clock("primary cpu clock"));
	kvm_guest_cpu_init();
	native_smp_prepare_boot_cpu();
}

static void __cpuinit kvm_guest_cpu_online(void *dummy)
{
	kvm_guest_cpu_init();
}

static void kvm_guest_cpu_offline(void *dummy)
{
	kvm_disable_steal_time();
	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
		wrmsrl(MSR_KVM_PV_EOI_EN, 0);
	kvm_pv_disable_apf();
	apf_task_wake_all();
}

static int __cpuinit kvm_cpu_notify(struct notifier_block *self,
				    unsigned long action, void *hcpu)
{
	int cpu = (unsigned long)hcpu;
	switch (action) {
	case CPU_ONLINE:
	case CPU_DOWN_FAILED:
	case CPU_ONLINE_FROZEN:
		smp_call_function_single(cpu, kvm_guest_cpu_online, NULL, 0);
		break;
	case CPU_DOWN_PREPARE:
	case CPU_DOWN_PREPARE_FROZEN:
		smp_call_function_single(cpu, kvm_guest_cpu_offline, NULL, 1);
		break;
	default:
		break;
	}
	return NOTIFY_OK;
}

static struct notifier_block __cpuinitdata kvm_cpu_notifier = {
        .notifier_call  = kvm_cpu_notify,
};
#endif

static void __init kvm_apf_trap_init(void)
{
	set_intr_gate(14, &async_page_fault);
}

void __init kvm_guest_init(void)
{
	int i;

	if (!kvm_para_available())
		return;

	paravirt_ops_setup();
	register_reboot_notifier(&kvm_pv_reboot_nb);
	for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++)
		spin_lock_init(&async_pf_sleepers[i].lock);
	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF))
		x86_init.irqs.trap_init = kvm_apf_trap_init;

	if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
		has_steal_clock = 1;
		pv_time_ops.steal_clock = kvm_steal_clock;
	}

	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
		apic_set_eoi_write(kvm_guest_apic_eoi_write);

#ifdef CONFIG_SMP
	smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
	register_cpu_notifier(&kvm_cpu_notifier);
#else
	kvm_guest_cpu_init();
#endif
}

static bool __init kvm_detect(void)
{
	if (!kvm_para_available())
		return false;
	return true;
}

const struct hypervisor_x86 x86_hyper_kvm __refconst = {
	.name			= "KVM",
	.detect			= kvm_detect,
};
EXPORT_SYMBOL_GPL(x86_hyper_kvm);

static __init int activate_jump_labels(void)
{
	if (has_steal_clock) {
		static_key_slow_inc(&paravirt_steal_enabled);
		if (steal_acc)
			static_key_slow_inc(&paravirt_steal_rq_enabled);
	}

	return 0;
}
arch_initcall(activate_jump_labels);
Commit	Line	Data
0cf1bfd2 MT	1	/*
	2	* KVM paravirt_ops implementation
	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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
	17	*
	18	* Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
	19	* Copyright IBM Corporation, 2007
	20	* Authors: Anthony Liguori <aliguori@us.ibm.com>
	21	*/
	22
	23	#include <linux/module.h>
	24	#include <linux/kernel.h>
	25	#include <linux/kvm_para.h>
	26	#include <linux/cpu.h>
	27	#include <linux/mm.h>
1da8a77b	28	#include <linux/highmem.h>
096d14a3	29	#include <linux/hardirq.h>
fd10cde9 GN	30	#include <linux/notifier.h>
fd10cde9 GN	31	#include <linux/reboot.h>
631bc487 GN	32	#include <linux/hash.h>
	33	#include <linux/sched.h>
	34	#include <linux/slab.h>
	35	#include <linux/kprobes.h>
a90ede7b	36	#include <asm/timer.h>
fd10cde9	37	#include <asm/cpu.h>
631bc487 GN	38	#include <asm/traps.h>
631bc487 GN	39	#include <asm/desc.h>
6c047cd9	40	#include <asm/tlbflush.h>
e0875921	41	#include <asm/idle.h>
ab9cf499 MT	42	#include <asm/apic.h>
ab9cf499 MT	43	#include <asm/apicdef.h>
fc73373b	44	#include <asm/hypervisor.h>
096d14a3	45
fd10cde9 GN	46	static int kvmapf = 1;
	47
	48	static int parse_no_kvmapf(char *arg)
	49	{
	50	kvmapf = 0;
	51	return 0;
	52	}
	53
	54	early_param("no-kvmapf", parse_no_kvmapf);
	55
d910f5c1 GC	56	static int steal_acc = 1;
	57	static int parse_no_stealacc(char *arg)
	58	{
	59	steal_acc = 0;
	60	return 0;
	61	}
	62
	63	early_param("no-steal-acc", parse_no_stealacc);
	64
fd10cde9	65	static DEFINE_PER_CPU(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);
d910f5c1 GC	66	static DEFINE_PER_CPU(struct kvm_steal_time, steal_time) __aligned(64);
d910f5c1 GC	67	static int has_steal_clock = 0;
096d14a3	68
0cf1bfd2 MT	69	/*
	70	* No need for any "IO delay" on KVM
	71	*/
	72	static void kvm_io_delay(void)
	73	{
	74	}
	75
631bc487 GN	76	#define KVM_TASK_SLEEP_HASHBITS 8
	77	#define KVM_TASK_SLEEP_HASHSIZE (1<<KVM_TASK_SLEEP_HASHBITS)
	78
	79	struct kvm_task_sleep_node {
	80	struct hlist_node link;
	81	wait_queue_head_t wq;
	82	u32 token;
	83	int cpu;
6c047cd9	84	bool halted;
631bc487 GN	85	};
	86
	87	static struct kvm_task_sleep_head {
	88	spinlock_t lock;
	89	struct hlist_head list;
	90	} async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE];
	91
	92	static struct kvm_task_sleep_node _find_apf_task(struct kvm_task_sleep_head b,
	93	u32 token)
	94	{
	95	struct hlist_node *p;
	96
	97	hlist_for_each(p, &b->list) {
	98	struct kvm_task_sleep_node *n =
	99	hlist_entry(p, typeof(*n), link);
	100	if (n->token == token)
	101	return n;
	102	}
	103
	104	return NULL;
	105	}
	106
	107	void kvm_async_pf_task_wait(u32 token)
	108	{
	109	u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
	110	struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
	111	struct kvm_task_sleep_node n, *e;
	112	DEFINE_WAIT(wait);
6c047cd9 GN	113	int cpu, idle;
	114
	115	cpu = get_cpu();
	116	idle = idle_cpu(cpu);
	117	put_cpu();
631bc487 GN	118
	119	spin_lock(&b->lock);
	120	e = _find_apf_task(b, token);
	121	if (e) {
	122	/* dummy entry exist -> wake up was delivered ahead of PF */
	123	hlist_del(&e->link);
	124	kfree(e);
	125	spin_unlock(&b->lock);
	126	return;
	127	}
	128
	129	n.token = token;
	130	n.cpu = smp_processor_id();
6c047cd9	131	n.halted = idle \|\| preempt_count() > 1;
631bc487 GN	132	init_waitqueue_head(&n.wq);
	133	hlist_add_head(&n.link, &b->list);
	134	spin_unlock(&b->lock);
	135
	136	for (;;) {
6c047cd9 GN	137	if (!n.halted)
6c047cd9 GN	138	prepare_to_wait(&n.wq, &wait, TASK_UNINTERRUPTIBLE);
631bc487 GN	139	if (hlist_unhashed(&n.link))
631bc487 GN	140	break;
6c047cd9 GN	141
	142	if (!n.halted) {
	143	local_irq_enable();
	144	schedule();
	145	local_irq_disable();
	146	} else {
	147	/*
	148	* We cannot reschedule. So halt.
	149	*/
	150	native_safe_halt();
	151	local_irq_disable();
	152	}
631bc487	153	}
6c047cd9 GN	154	if (!n.halted)
6c047cd9 GN	155	finish_wait(&n.wq, &wait);
631bc487 GN	156
	157	return;
	158	}
	159	EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait);
	160
	161	static void apf_task_wake_one(struct kvm_task_sleep_node *n)
	162	{
	163	hlist_del_init(&n->link);
6c047cd9 GN	164	if (n->halted)
	165	smp_send_reschedule(n->cpu);
	166	else if (waitqueue_active(&n->wq))
631bc487 GN	167	wake_up(&n->wq);
	168	}
	169
	170	static void apf_task_wake_all(void)
	171	{
	172	int i;
	173
	174	for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) {
	175	struct hlist_node p, next;
	176	struct kvm_task_sleep_head *b = &async_pf_sleepers[i];
	177	spin_lock(&b->lock);
	178	hlist_for_each_safe(p, next, &b->list) {
	179	struct kvm_task_sleep_node *n =
	180	hlist_entry(p, typeof(*n), link);
	181	if (n->cpu == smp_processor_id())
	182	apf_task_wake_one(n);
	183	}
	184	spin_unlock(&b->lock);
	185	}
	186	}
	187
	188	void kvm_async_pf_task_wake(u32 token)
	189	{
	190	u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
	191	struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
	192	struct kvm_task_sleep_node *n;
	193
	194	if (token == ~0) {
	195	apf_task_wake_all();
	196	return;
	197	}
	198
	199	again:
	200	spin_lock(&b->lock);
	201	n = _find_apf_task(b, token);
	202	if (!n) {
	203	/*
	204	* async PF was not yet handled.
	205	* Add dummy entry for the token.
	206	*/
62c49cc9	207	n = kzalloc(sizeof(*n), GFP_ATOMIC);
631bc487 GN	208	if (!n) {
	209	/*
	210	* Allocation failed! Busy wait while other cpu
	211	* handles async PF.
	212	*/
	213	spin_unlock(&b->lock);
	214	cpu_relax();
	215	goto again;
	216	}
	217	n->token = token;
	218	n->cpu = smp_processor_id();
	219	init_waitqueue_head(&n->wq);
	220	hlist_add_head(&n->link, &b->list);
	221	} else
	222	apf_task_wake_one(n);
	223	spin_unlock(&b->lock);
	224	return;
	225	}
	226	EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);
	227
	228	u32 kvm_read_and_reset_pf_reason(void)
	229	{
	230	u32 reason = 0;
	231
	232	if (__get_cpu_var(apf_reason).enabled) {
	233	reason = __get_cpu_var(apf_reason).reason;
	234	__get_cpu_var(apf_reason).reason = 0;
	235	}
	236
	237	return reason;
	238	}
	239	EXPORT_SYMBOL_GPL(kvm_read_and_reset_pf_reason);
	240
	241	dotraplinkage void __kprobes
	242	do_async_page_fault(struct pt_regs *regs, unsigned long error_code)
	243	{
	244	switch (kvm_read_and_reset_pf_reason()) {
	245	default:
	246	do_page_fault(regs, error_code);
	247	break;
	248	case KVM_PV_REASON_PAGE_NOT_PRESENT:
	249	/* page is swapped out by the host. */
c5e015d4 SL	250	rcu_irq_enter();
c5e015d4 SL	251	exit_idle();
631bc487	252	kvm_async_pf_task_wait((u32)read_cr2());
c5e015d4	253	rcu_irq_exit();
631bc487 GN	254	break;
631bc487 GN	255	case KVM_PV_REASON_PAGE_READY:
e0875921 GN	256	rcu_irq_enter();
e0875921 GN	257	exit_idle();
631bc487	258	kvm_async_pf_task_wake((u32)read_cr2());
e0875921	259	rcu_irq_exit();
631bc487 GN	260	break;
	261	}
	262	}
	263
d3ac8815	264	static void __init paravirt_ops_setup(void)
0cf1bfd2 MT	265	{
	266	pv_info.name = "KVM";
	267	pv_info.paravirt_enabled = 1;
	268
	269	if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
	270	pv_cpu_ops.io_delay = kvm_io_delay;
	271
a90ede7b MT	272	#ifdef CONFIG_X86_IO_APIC
	273	no_timer_check = 1;
	274	#endif
0cf1bfd2 MT	275	}
0cf1bfd2 MT	276
d910f5c1 GC	277	static void kvm_register_steal_time(void)
	278	{
	279	int cpu = smp_processor_id();
	280	struct kvm_steal_time *st = &per_cpu(steal_time, cpu);
	281
	282	if (!has_steal_clock)
	283	return;
	284
	285	memset(st, 0, sizeof(*st));
	286
	287	wrmsrl(MSR_KVM_STEAL_TIME, (__pa(st) \| KVM_MSR_ENABLED));
	288	printk(KERN_INFO "kvm-stealtime: cpu %d, msr %lx\n",
	289	cpu, __pa(st));
	290	}
	291
ab9cf499 MT	292	static DEFINE_PER_CPU(unsigned long, kvm_apic_eoi) = KVM_PV_EOI_DISABLED;
	293
	294	static void kvm_guest_apic_eoi_write(u32 reg, u32 val)
	295	{
	296	/**
	297	* This relies on __test_and_clear_bit to modify the memory
	298	* in a way that is atomic with respect to the local CPU.
	299	* The hypervisor only accesses this memory from the local CPU so
	300	* there's no need for lock or memory barriers.
	301	* An optimization barrier is implied in apic write.
	302	*/
	303	if (__test_and_clear_bit(KVM_PV_EOI_BIT, &__get_cpu_var(kvm_apic_eoi)))
	304	return;
90536664	305	apic_write(APIC_EOI, APIC_EOI_ACK);
ab9cf499 MT	306	}
ab9cf499 MT	307
fd10cde9 GN	308	void __cpuinit kvm_guest_cpu_init(void)
	309	{
	310	if (!kvm_para_available())
	311	return;
	312
	313	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf) {
	314	u64 pa = __pa(&__get_cpu_var(apf_reason));
	315
6adba527 GN	316	#ifdef CONFIG_PREEMPT
	317	pa \|= KVM_ASYNC_PF_SEND_ALWAYS;
	318	#endif
fd10cde9 GN	319	wrmsrl(MSR_KVM_ASYNC_PF_EN, pa \| KVM_ASYNC_PF_ENABLED);
	320	__get_cpu_var(apf_reason).enabled = 1;
	321	printk(KERN_INFO"KVM setup async PF for cpu %d\n",
	322	smp_processor_id());
	323	}
d910f5c1	324
ab9cf499 MT	325	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) {
	326	unsigned long pa;
	327	/* Size alignment is implied but just to make it explicit. */
	328	BUILD_BUG_ON(__alignof__(kvm_apic_eoi) < 4);
	329	__get_cpu_var(kvm_apic_eoi) = 0;
	330	pa = __pa(&__get_cpu_var(kvm_apic_eoi)) \| KVM_MSR_ENABLED;
	331	wrmsrl(MSR_KVM_PV_EOI_EN, pa);
	332	}
	333
d910f5c1 GC	334	if (has_steal_clock)
d910f5c1 GC	335	kvm_register_steal_time();
fd10cde9 GN	336	}
fd10cde9 GN	337
ab9cf499	338	static void kvm_pv_disable_apf(void)
fd10cde9 GN	339	{
	340	if (!__get_cpu_var(apf_reason).enabled)
	341	return;
	342
	343	wrmsrl(MSR_KVM_ASYNC_PF_EN, 0);
	344	__get_cpu_var(apf_reason).enabled = 0;
	345
	346	printk(KERN_INFO"Unregister pv shared memory for cpu %d\n",
	347	smp_processor_id());
	348	}
	349
ab9cf499 MT	350	static void kvm_pv_guest_cpu_reboot(void *unused)
	351	{
	352	/*
	353	* We disable PV EOI before we load a new kernel by kexec,
	354	* since MSR_KVM_PV_EOI_EN stores a pointer into old kernel's memory.
	355	* New kernel can re-enable when it boots.
	356	*/
	357	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
	358	wrmsrl(MSR_KVM_PV_EOI_EN, 0);
	359	kvm_pv_disable_apf();
8fbe6a54	360	kvm_disable_steal_time();
ab9cf499 MT	361	}
ab9cf499 MT	362
fd10cde9 GN	363	static int kvm_pv_reboot_notify(struct notifier_block *nb,
	364	unsigned long code, void *unused)
	365	{
	366	if (code == SYS_RESTART)
ab9cf499	367	on_each_cpu(kvm_pv_guest_cpu_reboot, NULL, 1);
fd10cde9 GN	368	return NOTIFY_DONE;
	369	}
	370
	371	static struct notifier_block kvm_pv_reboot_nb = {
	372	.notifier_call = kvm_pv_reboot_notify,
	373	};
	374
d910f5c1 GC	375	static u64 kvm_steal_clock(int cpu)
	376	{
	377	u64 steal;
	378	struct kvm_steal_time *src;
	379	int version;
	380
	381	src = &per_cpu(steal_time, cpu);
	382	do {
	383	version = src->version;
	384	rmb();
	385	steal = src->steal;
	386	rmb();
	387	} while ((version & 1) \|\| (version != src->version));
	388
	389	return steal;
	390	}
	391
	392	void kvm_disable_steal_time(void)
	393	{
	394	if (!has_steal_clock)
	395	return;
	396
	397	wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
	398	}
	399
ca3f1017 GN	400	#ifdef CONFIG_SMP
	401	static void __init kvm_smp_prepare_boot_cpu(void)
	402	{
	403	WARN_ON(kvm_register_clock("primary cpu clock"));
fd10cde9	404	kvm_guest_cpu_init();
ca3f1017 GN	405	native_smp_prepare_boot_cpu();
ca3f1017 GN	406	}
fd10cde9	407
775077a0	408	static void __cpuinit kvm_guest_cpu_online(void *dummy)
fd10cde9 GN	409	{
	410	kvm_guest_cpu_init();
	411	}
	412
	413	static void kvm_guest_cpu_offline(void *dummy)
	414	{
d910f5c1	415	kvm_disable_steal_time();
ab9cf499 MT	416	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
	417	wrmsrl(MSR_KVM_PV_EOI_EN, 0);
	418	kvm_pv_disable_apf();
631bc487	419	apf_task_wake_all();
fd10cde9 GN	420	}
	421
	422	static int __cpuinit kvm_cpu_notify(struct notifier_block *self,
	423	unsigned long action, void *hcpu)
	424	{
	425	int cpu = (unsigned long)hcpu;
	426	switch (action) {
	427	case CPU_ONLINE:
	428	case CPU_DOWN_FAILED:
	429	case CPU_ONLINE_FROZEN:
	430	smp_call_function_single(cpu, kvm_guest_cpu_online, NULL, 0);
	431	break;
	432	case CPU_DOWN_PREPARE:
	433	case CPU_DOWN_PREPARE_FROZEN:
	434	smp_call_function_single(cpu, kvm_guest_cpu_offline, NULL, 1);
	435	break;
	436	default:
	437	break;
	438	}
	439	return NOTIFY_OK;
	440	}
	441
	442	static struct notifier_block __cpuinitdata kvm_cpu_notifier = {
	443	.notifier_call = kvm_cpu_notify,
	444	};
ca3f1017 GN	445	#endif
ca3f1017 GN	446
631bc487 GN	447	static void __init kvm_apf_trap_init(void)
	448	{
	449	set_intr_gate(14, &async_page_fault);
	450	}
	451
0cf1bfd2 MT	452	void __init kvm_guest_init(void)
0cf1bfd2 MT	453	{
631bc487 GN	454	int i;
631bc487 GN	455
0cf1bfd2 MT	456	if (!kvm_para_available())
	457	return;
	458
	459	paravirt_ops_setup();
fd10cde9	460	register_reboot_notifier(&kvm_pv_reboot_nb);
631bc487 GN	461	for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++)
	462	spin_lock_init(&async_pf_sleepers[i].lock);
	463	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF))
	464	x86_init.irqs.trap_init = kvm_apf_trap_init;
	465
d910f5c1 GC	466	if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
	467	has_steal_clock = 1;
	468	pv_time_ops.steal_clock = kvm_steal_clock;
	469	}
	470
90536664 MT	471	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
90536664 MT	472	apic_set_eoi_write(kvm_guest_apic_eoi_write);
ab9cf499	473
ca3f1017 GN	474	#ifdef CONFIG_SMP
ca3f1017 GN	475	smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
fd10cde9 GN	476	register_cpu_notifier(&kvm_cpu_notifier);
	477	#else
	478	kvm_guest_cpu_init();
ca3f1017	479	#endif
0cf1bfd2	480	}
d910f5c1	481
fc73373b PB	482	static bool __init kvm_detect(void)
	483	{
	484	if (!kvm_para_available())
	485	return false;
	486	return true;
	487	}
	488
	489	const struct hypervisor_x86 x86_hyper_kvm __refconst = {
	490	.name = "KVM",
	491	.detect = kvm_detect,
	492	};
	493	EXPORT_SYMBOL_GPL(x86_hyper_kvm);
	494
d910f5c1 GC	495	static __init int activate_jump_labels(void)
	496	{
	497	if (has_steal_clock) {
c5905afb	498	static_key_slow_inc(&paravirt_steal_enabled);
d910f5c1	499	if (steal_acc)
c5905afb	500	static_key_slow_inc(&paravirt_steal_rq_enabled);
d910f5c1 GC	501	}
	502
	503	return 0;
	504	}
	505	arch_initcall(activate_jump_labels);