[GitHub/mt8127/android_kernel_alcatel_ttab.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>
#include <asm/kvm_guest.h>
#include <asm/context_tracking.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 int kvmclock_vsyscall = 1;
static int parse_no_kvmclock_vsyscall(char *arg)
{
        kvmclock_vsyscall = 0;
        return 0;
}

early_param("no-kvmclock-vsyscall", parse_no_kvmclock_vsyscall);

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);

	rcu_irq_enter();

	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);

		rcu_irq_exit();
		return;
	}

	n.token = token;
	n.cpu = smp_processor_id();
	n.halted = is_idle_task(current) || 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.
			 */
			rcu_irq_exit();
			native_safe_halt();
			rcu_irq_enter();
			local_irq_disable();
		}
	}
	if (!n.halted)
		finish_wait(&n.wq, &wait);

	rcu_irq_exit();
	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. */
		exception_enter(regs);
		exit_idle();
		kvm_async_pf_task_wait((u32)read_cr2());
		exception_exit(regs);
		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);

	if (kvmclock_vsyscall)
		kvm_setup_vsyscall_timeinfo();

#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>
3dc4f7cf	45	#include <asm/kvm_guest.h>
9b132fbe	46	#include <asm/context_tracking.h>
096d14a3	47
fd10cde9 GN	48	static int kvmapf = 1;
	49
	50	static int parse_no_kvmapf(char *arg)
	51	{
	52	kvmapf = 0;
	53	return 0;
	54	}
	55
	56	early_param("no-kvmapf", parse_no_kvmapf);
	57
d910f5c1 GC	58	static int steal_acc = 1;
	59	static int parse_no_stealacc(char *arg)
	60	{
	61	steal_acc = 0;
	62	return 0;
	63	}
	64
	65	early_param("no-steal-acc", parse_no_stealacc);
	66
3dc4f7cf MT	67	static int kvmclock_vsyscall = 1;
	68	static int parse_no_kvmclock_vsyscall(char *arg)
	69	{
	70	kvmclock_vsyscall = 0;
	71	return 0;
	72	}
	73
	74	early_param("no-kvmclock-vsyscall", parse_no_kvmclock_vsyscall);
	75
fd10cde9	76	static DEFINE_PER_CPU(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);
d910f5c1 GC	77	static DEFINE_PER_CPU(struct kvm_steal_time, steal_time) __aligned(64);
d910f5c1 GC	78	static int has_steal_clock = 0;
096d14a3	79
0cf1bfd2 MT	80	/*
	81	* No need for any "IO delay" on KVM
	82	*/
	83	static void kvm_io_delay(void)
	84	{
	85	}
	86
631bc487 GN	87	#define KVM_TASK_SLEEP_HASHBITS 8
	88	#define KVM_TASK_SLEEP_HASHSIZE (1<<KVM_TASK_SLEEP_HASHBITS)
	89
	90	struct kvm_task_sleep_node {
	91	struct hlist_node link;
	92	wait_queue_head_t wq;
	93	u32 token;
	94	int cpu;
6c047cd9	95	bool halted;
631bc487 GN	96	};
	97
	98	static struct kvm_task_sleep_head {
	99	spinlock_t lock;
	100	struct hlist_head list;
	101	} async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE];
	102
	103	static struct kvm_task_sleep_node _find_apf_task(struct kvm_task_sleep_head b,
	104	u32 token)
	105	{
	106	struct hlist_node *p;
	107
	108	hlist_for_each(p, &b->list) {
	109	struct kvm_task_sleep_node *n =
	110	hlist_entry(p, typeof(*n), link);
	111	if (n->token == token)
	112	return n;
	113	}
	114
	115	return NULL;
	116	}
	117
	118	void kvm_async_pf_task_wait(u32 token)
	119	{
	120	u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
	121	struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
	122	struct kvm_task_sleep_node n, *e;
	123	DEFINE_WAIT(wait);
	124
9b132fbe LZ	125	rcu_irq_enter();
9b132fbe LZ	126
631bc487 GN	127	spin_lock(&b->lock);
	128	e = _find_apf_task(b, token);
	129	if (e) {
	130	/* dummy entry exist -> wake up was delivered ahead of PF */
	131	hlist_del(&e->link);
	132	kfree(e);
	133	spin_unlock(&b->lock);
9b132fbe LZ	134
9b132fbe LZ	135	rcu_irq_exit();
631bc487 GN	136	return;
	137	}
	138
	139	n.token = token;
	140	n.cpu = smp_processor_id();
859f8450	141	n.halted = is_idle_task(current) \|\| preempt_count() > 1;
631bc487 GN	142	init_waitqueue_head(&n.wq);
	143	hlist_add_head(&n.link, &b->list);
	144	spin_unlock(&b->lock);
	145
	146	for (;;) {
6c047cd9 GN	147	if (!n.halted)
6c047cd9 GN	148	prepare_to_wait(&n.wq, &wait, TASK_UNINTERRUPTIBLE);
631bc487 GN	149	if (hlist_unhashed(&n.link))
631bc487 GN	150	break;
6c047cd9 GN	151
	152	if (!n.halted) {
	153	local_irq_enable();
	154	schedule();
	155	local_irq_disable();
	156	} else {
	157	/*
	158	* We cannot reschedule. So halt.
	159	*/
9b132fbe	160	rcu_irq_exit();
6c047cd9	161	native_safe_halt();
9b132fbe	162	rcu_irq_enter();
6c047cd9 GN	163	local_irq_disable();
6c047cd9 GN	164	}
631bc487	165	}
6c047cd9 GN	166	if (!n.halted)
6c047cd9 GN	167	finish_wait(&n.wq, &wait);
631bc487	168
9b132fbe	169	rcu_irq_exit();
631bc487 GN	170	return;
	171	}
	172	EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait);
	173
	174	static void apf_task_wake_one(struct kvm_task_sleep_node *n)
	175	{
	176	hlist_del_init(&n->link);
6c047cd9 GN	177	if (n->halted)
	178	smp_send_reschedule(n->cpu);
	179	else if (waitqueue_active(&n->wq))
631bc487 GN	180	wake_up(&n->wq);
	181	}
	182
	183	static void apf_task_wake_all(void)
	184	{
	185	int i;
	186
	187	for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) {
	188	struct hlist_node p, next;
	189	struct kvm_task_sleep_head *b = &async_pf_sleepers[i];
	190	spin_lock(&b->lock);
	191	hlist_for_each_safe(p, next, &b->list) {
	192	struct kvm_task_sleep_node *n =
	193	hlist_entry(p, typeof(*n), link);
	194	if (n->cpu == smp_processor_id())
	195	apf_task_wake_one(n);
	196	}
	197	spin_unlock(&b->lock);
	198	}
	199	}
	200
	201	void kvm_async_pf_task_wake(u32 token)
	202	{
	203	u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
	204	struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
	205	struct kvm_task_sleep_node *n;
	206
	207	if (token == ~0) {
	208	apf_task_wake_all();
	209	return;
	210	}
	211
	212	again:
	213	spin_lock(&b->lock);
	214	n = _find_apf_task(b, token);
	215	if (!n) {
	216	/*
	217	* async PF was not yet handled.
	218	* Add dummy entry for the token.
	219	*/
62c49cc9	220	n = kzalloc(sizeof(*n), GFP_ATOMIC);
631bc487 GN	221	if (!n) {
	222	/*
	223	* Allocation failed! Busy wait while other cpu
	224	* handles async PF.
	225	*/
	226	spin_unlock(&b->lock);
	227	cpu_relax();
	228	goto again;
	229	}
	230	n->token = token;
	231	n->cpu = smp_processor_id();
	232	init_waitqueue_head(&n->wq);
	233	hlist_add_head(&n->link, &b->list);
	234	} else
	235	apf_task_wake_one(n);
	236	spin_unlock(&b->lock);
	237	return;
	238	}
	239	EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);
	240
	241	u32 kvm_read_and_reset_pf_reason(void)
	242	{
	243	u32 reason = 0;
	244
	245	if (__get_cpu_var(apf_reason).enabled) {
	246	reason = __get_cpu_var(apf_reason).reason;
	247	__get_cpu_var(apf_reason).reason = 0;
	248	}
	249
	250	return reason;
	251	}
	252	EXPORT_SYMBOL_GPL(kvm_read_and_reset_pf_reason);
	253
	254	dotraplinkage void __kprobes
	255	do_async_page_fault(struct pt_regs *regs, unsigned long error_code)
	256	{
	257	switch (kvm_read_and_reset_pf_reason()) {
	258	default:
	259	do_page_fault(regs, error_code);
	260	break;
	261	case KVM_PV_REASON_PAGE_NOT_PRESENT:
	262	/* page is swapped out by the host. */
9b132fbe	263	exception_enter(regs);
c5e015d4	264	exit_idle();
631bc487	265	kvm_async_pf_task_wait((u32)read_cr2());
9b132fbe	266	exception_exit(regs);
631bc487 GN	267	break;
631bc487 GN	268	case KVM_PV_REASON_PAGE_READY:
e0875921 GN	269	rcu_irq_enter();
e0875921 GN	270	exit_idle();
631bc487	271	kvm_async_pf_task_wake((u32)read_cr2());
e0875921	272	rcu_irq_exit();
631bc487 GN	273	break;
	274	}
	275	}
	276
d3ac8815	277	static void __init paravirt_ops_setup(void)
0cf1bfd2 MT	278	{
	279	pv_info.name = "KVM";
	280	pv_info.paravirt_enabled = 1;
	281
	282	if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
	283	pv_cpu_ops.io_delay = kvm_io_delay;
	284
a90ede7b MT	285	#ifdef CONFIG_X86_IO_APIC
	286	no_timer_check = 1;
	287	#endif
0cf1bfd2 MT	288	}
0cf1bfd2 MT	289
d910f5c1 GC	290	static void kvm_register_steal_time(void)
	291	{
	292	int cpu = smp_processor_id();
	293	struct kvm_steal_time *st = &per_cpu(steal_time, cpu);
	294
	295	if (!has_steal_clock)
	296	return;
	297
	298	memset(st, 0, sizeof(*st));
	299
	300	wrmsrl(MSR_KVM_STEAL_TIME, (__pa(st) \| KVM_MSR_ENABLED));
	301	printk(KERN_INFO "kvm-stealtime: cpu %d, msr %lx\n",
	302	cpu, __pa(st));
	303	}
	304
ab9cf499 MT	305	static DEFINE_PER_CPU(unsigned long, kvm_apic_eoi) = KVM_PV_EOI_DISABLED;
	306
	307	static void kvm_guest_apic_eoi_write(u32 reg, u32 val)
	308	{
	309	/**
	310	* This relies on __test_and_clear_bit to modify the memory
	311	* in a way that is atomic with respect to the local CPU.
	312	* The hypervisor only accesses this memory from the local CPU so
	313	* there's no need for lock or memory barriers.
	314	* An optimization barrier is implied in apic write.
	315	*/
	316	if (__test_and_clear_bit(KVM_PV_EOI_BIT, &__get_cpu_var(kvm_apic_eoi)))
	317	return;
90536664	318	apic_write(APIC_EOI, APIC_EOI_ACK);
ab9cf499 MT	319	}
ab9cf499 MT	320
fd10cde9 GN	321	void __cpuinit kvm_guest_cpu_init(void)
	322	{
	323	if (!kvm_para_available())
	324	return;
	325
	326	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf) {
	327	u64 pa = __pa(&__get_cpu_var(apf_reason));
	328
6adba527 GN	329	#ifdef CONFIG_PREEMPT
	330	pa \|= KVM_ASYNC_PF_SEND_ALWAYS;
	331	#endif
fd10cde9 GN	332	wrmsrl(MSR_KVM_ASYNC_PF_EN, pa \| KVM_ASYNC_PF_ENABLED);
	333	__get_cpu_var(apf_reason).enabled = 1;
	334	printk(KERN_INFO"KVM setup async PF for cpu %d\n",
	335	smp_processor_id());
	336	}
d910f5c1	337
ab9cf499 MT	338	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) {
	339	unsigned long pa;
	340	/* Size alignment is implied but just to make it explicit. */
	341	BUILD_BUG_ON(__alignof__(kvm_apic_eoi) < 4);
	342	__get_cpu_var(kvm_apic_eoi) = 0;
	343	pa = __pa(&__get_cpu_var(kvm_apic_eoi)) \| KVM_MSR_ENABLED;
	344	wrmsrl(MSR_KVM_PV_EOI_EN, pa);
	345	}
	346
d910f5c1 GC	347	if (has_steal_clock)
d910f5c1 GC	348	kvm_register_steal_time();
fd10cde9 GN	349	}
fd10cde9 GN	350
ab9cf499	351	static void kvm_pv_disable_apf(void)
fd10cde9 GN	352	{
	353	if (!__get_cpu_var(apf_reason).enabled)
	354	return;
	355
	356	wrmsrl(MSR_KVM_ASYNC_PF_EN, 0);
	357	__get_cpu_var(apf_reason).enabled = 0;
	358
	359	printk(KERN_INFO"Unregister pv shared memory for cpu %d\n",
	360	smp_processor_id());
	361	}
	362
ab9cf499 MT	363	static void kvm_pv_guest_cpu_reboot(void *unused)
	364	{
	365	/*
	366	* We disable PV EOI before we load a new kernel by kexec,
	367	* since MSR_KVM_PV_EOI_EN stores a pointer into old kernel's memory.
	368	* New kernel can re-enable when it boots.
	369	*/
	370	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
	371	wrmsrl(MSR_KVM_PV_EOI_EN, 0);
	372	kvm_pv_disable_apf();
8fbe6a54	373	kvm_disable_steal_time();
ab9cf499 MT	374	}
ab9cf499 MT	375
fd10cde9 GN	376	static int kvm_pv_reboot_notify(struct notifier_block *nb,
	377	unsigned long code, void *unused)
	378	{
	379	if (code == SYS_RESTART)
ab9cf499	380	on_each_cpu(kvm_pv_guest_cpu_reboot, NULL, 1);
fd10cde9 GN	381	return NOTIFY_DONE;
	382	}
	383
	384	static struct notifier_block kvm_pv_reboot_nb = {
	385	.notifier_call = kvm_pv_reboot_notify,
	386	};
	387
d910f5c1 GC	388	static u64 kvm_steal_clock(int cpu)
	389	{
	390	u64 steal;
	391	struct kvm_steal_time *src;
	392	int version;
	393
	394	src = &per_cpu(steal_time, cpu);
	395	do {
	396	version = src->version;
	397	rmb();
	398	steal = src->steal;
	399	rmb();
	400	} while ((version & 1) \|\| (version != src->version));
	401
	402	return steal;
	403	}
	404
	405	void kvm_disable_steal_time(void)
	406	{
	407	if (!has_steal_clock)
	408	return;
	409
	410	wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
	411	}
	412
ca3f1017 GN	413	#ifdef CONFIG_SMP
	414	static void __init kvm_smp_prepare_boot_cpu(void)
	415	{
	416	WARN_ON(kvm_register_clock("primary cpu clock"));
fd10cde9	417	kvm_guest_cpu_init();
ca3f1017 GN	418	native_smp_prepare_boot_cpu();
ca3f1017 GN	419	}
fd10cde9	420
775077a0	421	static void __cpuinit kvm_guest_cpu_online(void *dummy)
fd10cde9 GN	422	{
	423	kvm_guest_cpu_init();
	424	}
	425
	426	static void kvm_guest_cpu_offline(void *dummy)
	427	{
d910f5c1	428	kvm_disable_steal_time();
ab9cf499 MT	429	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
	430	wrmsrl(MSR_KVM_PV_EOI_EN, 0);
	431	kvm_pv_disable_apf();
631bc487	432	apf_task_wake_all();
fd10cde9 GN	433	}
	434
	435	static int __cpuinit kvm_cpu_notify(struct notifier_block *self,
	436	unsigned long action, void *hcpu)
	437	{
	438	int cpu = (unsigned long)hcpu;
	439	switch (action) {
	440	case CPU_ONLINE:
	441	case CPU_DOWN_FAILED:
	442	case CPU_ONLINE_FROZEN:
	443	smp_call_function_single(cpu, kvm_guest_cpu_online, NULL, 0);
	444	break;
	445	case CPU_DOWN_PREPARE:
	446	case CPU_DOWN_PREPARE_FROZEN:
	447	smp_call_function_single(cpu, kvm_guest_cpu_offline, NULL, 1);
	448	break;
	449	default:
	450	break;
	451	}
	452	return NOTIFY_OK;
	453	}
	454
	455	static struct notifier_block __cpuinitdata kvm_cpu_notifier = {
	456	.notifier_call = kvm_cpu_notify,
	457	};
ca3f1017 GN	458	#endif
ca3f1017 GN	459
631bc487 GN	460	static void __init kvm_apf_trap_init(void)
	461	{
	462	set_intr_gate(14, &async_page_fault);
	463	}
	464
0cf1bfd2 MT	465	void __init kvm_guest_init(void)
0cf1bfd2 MT	466	{
631bc487 GN	467	int i;
631bc487 GN	468
0cf1bfd2 MT	469	if (!kvm_para_available())
	470	return;
	471
	472	paravirt_ops_setup();
fd10cde9	473	register_reboot_notifier(&kvm_pv_reboot_nb);
631bc487 GN	474	for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++)
	475	spin_lock_init(&async_pf_sleepers[i].lock);
	476	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF))
	477	x86_init.irqs.trap_init = kvm_apf_trap_init;
	478
d910f5c1 GC	479	if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
	480	has_steal_clock = 1;
	481	pv_time_ops.steal_clock = kvm_steal_clock;
	482	}
	483
90536664 MT	484	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
90536664 MT	485	apic_set_eoi_write(kvm_guest_apic_eoi_write);
ab9cf499	486
3dc4f7cf MT	487	if (kvmclock_vsyscall)
	488	kvm_setup_vsyscall_timeinfo();
	489
ca3f1017 GN	490	#ifdef CONFIG_SMP
ca3f1017 GN	491	smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
fd10cde9 GN	492	register_cpu_notifier(&kvm_cpu_notifier);
	493	#else
	494	kvm_guest_cpu_init();
ca3f1017	495	#endif
0cf1bfd2	496	}
d910f5c1	497
fc73373b PB	498	static bool __init kvm_detect(void)
	499	{
	500	if (!kvm_para_available())
	501	return false;
	502	return true;
	503	}
	504
	505	const struct hypervisor_x86 x86_hyper_kvm __refconst = {
	506	.name = "KVM",
	507	.detect = kvm_detect,
	508	};
	509	EXPORT_SYMBOL_GPL(x86_hyper_kvm);
	510
d910f5c1 GC	511	static __init int activate_jump_labels(void)
	512	{
	513	if (has_steal_clock) {
c5905afb	514	static_key_slow_inc(&paravirt_steal_enabled);
d910f5c1	515	if (steal_acc)
c5905afb	516	static_key_slow_inc(&paravirt_steal_rq_enabled);
d910f5c1 GC	517	}
	518
	519	return 0;
	520	}
	521	arch_initcall(activate_jump_labels);